Third Generation Mobile System (3G): Cdma2000
Upcoming SlideShare
Loading in...5
×

Like this? Share it with your network

Share
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads

Views

Total Views
1,153
On Slideshare
1,153
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
81
Comments
0
Likes
1

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Mobile Evolution to 3G Third Generation Mobile System (3G): Cdma2000 1) INTRODUCRTION:1.1) Market requirements and services for 3G mobile radio system 2G are very successful world wide in providing services to users. But the customer base increasing much faster than initially expected. UMTS expecting around 400 million mobile subscribers world wide in year 2000, and about 1800 million subscribers in the year 2010, However 2G are limited in maximum data rates, also high percentage of mobile multimedia users will increase after year 2000. UMTS also expected in 2010 that 60% of the traffic in Europe would be created by mobile multimedia. A similar growth of mobile data traffic is expects in worldwide. Market requirements need more advanced services than current voice and low data rate services. Market requirements are classified in three different sections: ١
  • 2. Mobile Evolution to 3G UMTSComputer data Telecommunication audio- video content• Computer data • Mobility • Video on• E-mail • Video demand• Real time image conferencing • Interactive transfer • GSM, ISDN video services• Multimedia service • Electronic document transfer • Video newspaper• Mobile telephony • Telescoping computing • Wide band data • Value-added services internet services Fig 1 Future service will range from low up to high user data rate (maximum 2Mbps for IMT-2000/UMTS systems). The transmission of, for example, a large presentation of a size of 16Mbps would need 8 second with a 2Mbps service compared to current data transmission in GSM with 9.6Kbps, where 28 minutes would be necessary ٢
  • 3. Mobile Evolution to 3G 1.2) Technical requirement and radio environment Mbps 10 M Wireless terminal 1.0 0.1 3G uniting FDD- and TDD-services 2G FDD: e.g. GSM, IS-136, IS-95 CDMA, 2G TDD: PDC E.g. DECT, PHS 0.01 Office or room Building stationary Pedestrian vehicular Indoor Outdoor Fig 2These market requirements and services need results in international technicalrequirement for ongoing definition of third generation mobile radio systems. High data rates requirements are up to at least 144Kbps in vehicular up to at least 384Kbps in outdoor to indoor, and up to 2Mbps indoor and picocell environment. Circuit-switched and packet-switched services for symmetric and asymmetric need to be supported. Third generation systems will operates in all radio environments. In addition, the ability for global roaming has to be supported in the system design. ٣
  • 4. Mobile Evolution to 3G1.3) Comparison between 2G &2.5G and 3G Aspects 2G 2.5G 3G Frequency band They operates at The same as 2G Use of common multiple global frequency frequency bands, band from 800 MHz ,900 1885 to 2025 MHz (cellular MHz and band) and in from 2110 to 1.5GHz, 1.8GHz 2200 MHz (PCS band) Roaming Generally limited The same as 2G Improved in to specific region global roaming due to the use of due to the use of SIM, and UIM common global modules frequency. facilitating border roaming capability Data services Good for voice , Good for voice. Perfect for voice, but limited in But improved in support many data application data services by data services less than 32kbps using GPRS that than 2G and can operates at 2.5G, from 172kbps, EDGE 144kbps in that can operates mobility till a1t 384kbps 2Mcps indoor Digital modulation Use Gaussian GPRS is the Use quadrate phase minimum shift same like GSM, shift keying keying (GMSK) EDGE use 8 for GSM , and phase shift (QPSK) 64 array keying (8PSK) orthogonal modulation for IS-95 ٤
  • 5. Mobile Evolution to 3GCommonality for They are primary The same as 2G A key objectivedifferent optimized for is maximizingoperating specific the commonalityenvironment operating optimization of environment radio (e.g. vehicular & interference for pedestrian and multiple may assign for operating fixed wireless environment, access (FWA) (e.g. vehicular, pedestrian, office, FWA and satellite operation)Quality of Limited quality of Improved QOS Better QOS haveservices services due to compared to 2G 4 classes and presence of(QOS) but still didn’t differ for the blocking, limited capacity meet the market type of data requirement application used. Conversational class used for (e.g. voice call) and streaming class used for (e.g. video on demand) these two classes are used for delay sensitive application. Interactive class used for (e.g. e- mail and telnet) and background class used for (e.g. downloading) the last two types of QOS used for delay insensitive application. ٥
  • 6. Mobile Evolution to 3G Type of Use only circuit Use packet and Use packet and switching switching circuit switching circuit switching Table 11.4) 2G to 3G Evolution GSM Associations ETSI associatio T1 UWCC TIA CDG 2G GSM TDMA IS-95 IS-136 2.5G GPRS/EDGE 1XRTT HDR 3G W-CDMA UWC-136 Cdma2000 3G harmonization 3GPP UWCC 3GPP2 Group Fig 3As we saw from this flow chart that there is three systems for the secondgeneration. GSM from Europe and IS-136 from America that is working overlaidon the old analog system AMPS, and the third one is IS-95 that is completelydigital. And the two main proposals those will path for the 3G Is w-CDMA from Europe, and cdma2000 from America, which is multi- carrier from IS-95? That will be explained later.1.5) Standardizing comminute for 3G mobileInternational Mobile Telecommunications 2000 (IMT-2000), a representativename for third generation (3G) mobile communication system, aims to providean effective solution for the next-generation mobile services. ٦
  • 7. Mobile Evolution to 3GProgressing from the previous two generations, the technologies for the (3G)mobile system have been significantly improved in terms of system capacity,voice quality, and ease of use.3G systems are expected to offer better system capacity and higher data ratetransmission speed to support wireless Internet access and wire-less multimediaservices (including audio, video and images). To bridge 2G technologies to 3Gtechnologies. EDGE and GPRS were introduced; they are typically referred to as2.5G technologies.The initiation of 3G comes from manufactures, not operators. Work on 3Gstarted around 1992, when international telecommunication union (ITU) formedtask group (TG) 8/1 working on FPLMTS, which was later renamed IMT-2000 in1996 or 1997. Work in TG 8/1 was accelerated in 1994, which involvedgovernment agents, manufactures, and operators around the world. In 1996 NTTand Ericsson initiated 3 g developments. In 1997, the U. S. Telecommunicationindustry association (TIA) chose the CDMA technology for the 3G. Europeantelecommunication standards institute (ETSI) also selected the CDMA technologyfor the 3G. In the same year, Wideband CDMA (W-CDMA), cdma2000, and 3Gtime division duplexing (TDD) were developed by the universal mobiletelecommunication system (UMTS), TIA 45.5, and china /Europe, respectively.The 3G technology supports 144kbps bandwidth, with high-speed movement (e.g.in vehicles), 384kbps bandwidth with pedestrian (e.g. on campus), and 2Mbps forstationary (e.g. in buildings). The services will include high- quality voice,Internet / Intranet accesses, and multimedia. ٧
  • 8. Mobile Evolution to 3G1.5.1) Paradigm Shifts in Third-Generation SystemsWireless data transmission via mobile system offers tremendous opportunities fortechnologists and entrepreneurs ensure to provide their services at the right placeand the right time. The concepts of the third-generation systems introduce two paradigm shifts: 1) The shift from voice centric traffic to data centric traffic demands a packet-based infrastructure of the irrational circuit- based infrastructure. 2) Data applications continue to evolve: As a result, advanced application protocols and human interfaces become very crucial in practical applications 3G wireless communications requires a very broadband spectrum and fast data to support high-quality Internet access and multimedia services. Bandwidth, however is always limited the next table lists the existing spectrum used by the 2G systems and new sum Allocated for 3G. According to the table, only 25 percent (155 MHz out of 628 MHz) of the spectrum is newly created for the terrestrial 3G usage. Terrestrial spectrum allocation for 2G and 3G SPECTRUM BANDWIDTH SYSTEMS 50 MHz Amps, IS-95, IS- 800 MHz 136 900 MHz 50 MHz GSM 900 1500 MHz 48 MHz Japan PDC 1700 MHz 60 MHz Korean PCS 1800 MHz 150 MHz GSM 1800 1900 MHz 120 MHz PCS 2100 MHz 155 MHz 3G Table 2 ٨
  • 9. Mobile Evolution to 3G1.6) W-CDMA and cdma2000 The CDMA- based 3G standards selected from numerous proposals to ITU have become the major stream for IMT-2000. In practical, W- CDMA and cdma2000 are two major proposals for the third- generation systems. Even though both systems are CDMA-based, many distinguishing features can be identified, as listed in the next table for one, W-CDMA uses dedicated time division multiplexing (TDM) pilot signal, where by the channel estimation information is collected from another signal stream. This approach reduces the overall pilot power. In contrast, cdma2000 uses common code division multiplexing (CDM) pilot, where by channel estimation information can be collected by signal stream. W-CDMA does not need base station timing synchronization, whereas base station timing synchronization in cdma2000 can provide decreased latency and reduced chance of dropping calls during soft handoff. Comparison between W-CDMA and cdma2000 TECHNOLOGY W-CDMA CDMA2000 Chip rate 4.096 then become 3.6864Mcps 3.84Mcps Forward link pilot Dedicated pilot with Common pilot with structure TDM CDM Base station timing Asynchronous Synchronous using synchronization GPS receivers Forward link modes A multi-carrier mode capable of overlay onto IS-95 carriers Spectrum efficiency 17.8/22.4 for self 36.7/29 for self for forward link evolution evolution /reverse link measured 18.4/22 for chines 26.4/27.2 for chines by Erlang/MHz/cell evolution evolution ٩
  • 10. Mobile Evolution to 3G Table 9.3 The impact of system normalized spectrum efficiency in Erlang/MHz/cell for voice services in a vehicular environment was shown in the previous table shown * Higher Erlang/MHz/Omni cell equates to greater efficiency9.1.7) Harmonization Since both W-CDMA and cdma2000 have been simultaneously adapted for the 3G standard, harmonization of these two systems becomes necessary to make IMT-2000 deployment successful. Two crucial events have significantly enhanced harmonization of W-CDMA and cdma2000. The first is Ericsson’s acquisition of Qualcomm’s infrastructure division, which resolved contention of intellectual property rights (IPR) between the two companies. The second event is the adoption of operator’s harmonization group (OHG) recommendations by all major players. OHG has drawn its harmonization framework heavily from W-CDMA and cdma2000. The goals are: • To provide the foundation for accelerated growth in the 3G millennium • To create a single integrated 3G CDMA specification and process from the separate W-CDMA and cdma2000 proposals being developed by the third generation partnership project (3GPP) and (3GPP2). ١٠
  • 11. Mobile Evolution to 3GOHG’s efforts have result in: • A direct spread mode with 3.84Mcps for new frequency bands, and multi-carrier mode with 3.6864Mcps for operation overlaid to IS-95 signals. • A CDM pilot added to the direct spread mode • A harmonized solution for SCDMA (a TDD mode Third Generation system proposed by china) The manufacturing community has agreed to cross-license intellectual property on fair, reasonable and nondiscriminatory terms for 3G development. However, due to political reasons, the two chip rates and the two synchronous and asynchronous systems are likely to coexist. Furthermore, the equipment Supplies have their own concerns on current markets and wireless technologies. Thus it is likely that the 3G harmonization cannot be achieved at the physical layer. Instead more efforts will be spent on interoperability oh higher layer protocols for W-CDMA and cdma2000, which results in higher costs with degraded performance. The activities of the 3G development so far have focused on physical and MAC layers. Three radio modules (modes) were selected for 3G CDMA radio access: MODE FDD(DS) FDD(MC) TDD Chip rate 3.84MCps 3.6864MCps 3.84MCps Common pilot CDM CDM To be determined Dedicated pilot TDM CDM To be determined Base station Asynchronous/ Synchronous as To be determined synchronization synchronous cdma2000 Table 4 ١١
  • 12. Mobile Evolution to 3G • Direct sequencing (DS) frequency division duplex (FDD) mode 1 • Multi-carrier (MC) FDD mode 2 • Time division duplex (TDD) mode The direct sequence mode will be based on the W-CDMA proposal, and the MC mode will be based on the cdma2000 proposal. The TDD mode is an unpaired band solution to better facilitate indoors cordless communications; it has been studied in china. This mode provides asymmetric data services and is a potential low-cost solution.1.8) Quality of services in 3G From the viewpoint of end users, QOS should be provided on the end- to-end basis. QOS attributes should be general but simple, and their number should be small. From the point of view of the network, QOS will be defined with a set of parameters blocking probability, voice quality, data application, and time of service...Etc. The 3G QOS control mechanism should: 1) Efficiently utilize resources based on the ability to dynamically change QOS parameters during a communication session 2) Interwork with current QOS schemes 3) Present end-to-end QOS to the users with appropriate mapping. The end-to-end service on the application level uses the bearer services of the underlying networks, partitioned into three segments. ١٢
  • 13. Mobile Evolution to 3G1) The local bearer service provides a connection between terminalequipment (TE) and mobile equipment (ME). A TE can be a PC or PADconnected to the 3G network through a MT.2) The 3G-bearer service provides 3G QOS.3) An external bearer service provides the connection to the other partyin the call. This bearer may utilize several network services (e.g. another3G bearer service) connecting to the other party of the communicationsessionThe QOS classes defined for mobile networks are very different fromfixed networks due to the restrictions and limitations of the air interface.Based on delay sensitivity,Four QOS classes have been defined for 3G traffic: conversational,streaming, interactive, and background.Conversational class is defined for the most delay-sensitive applications(traditional voice calls), and the transfer delay is strictly limited.Steaming class is defined for one-way real time video/audio (e.g. video-on-demand).Both conversational and streaming classes will need better channelcoding and retransmission to reduce the error rate in order to meet therequired QOS.Interactive and background classes and defined for delay-insensitiveservices. The interactive class is used for application such as Telnet,interactive e-mail, and web browsing.The background class is defined for activities such as ftp or backgrounddownloading of e-mails.Among traffic classes just listed, the conversational class is most delay-sensitive, and the background class is the most delay-insensitive ١٣
  • 14. Mobile Evolution to 3G 2) Reverse LinkIn CDMA 2000 we have seven different radio configurations, to accommodatedifferent requirements of users; here we summarize these radio configurations Radio Configuration Characteristics for the Reverse CDMA Channel Radio Associated Data Rates, Forward Error Correction, Config Spreading and General Characteristics Rate 1200, 2400, 4800, and 9600 bps data rates with R = 1/3, 1 1 64-ary orthogonal modulation 1800, 3600, 7200, and 14400 bps data rates with 2 1 R = 1/2, 64-ary orthogonal modulation 1500, 2700, 4800, 9600, 19200, 38400, 76800, and 3 1 153600 bps with R = 1/4, 307200 bps data rate with R = 1/2, BPSK modulation with a pilot 1800, 3600, 7200, 14400, 28800, 57600, 115200, and 4 1 230400 with R = 1/4, BPSK modulation with a pilot ١٤
  • 15. Mobile Evolution to 3G 1500, 2700, 4800, 9600, 19200, 38400, 76800, and 5 3 153600 bps with R = 1/4, 307200 and 614400 bps data rate with R = 1/3, BPSK modulation with a pilot 1800, 3600, 7200, 14400, 28800, 57600, 115200, 6 3 230400, and 460800 bps with R = 1/4, 1036800 bps data rate with R = ½, BPSK modulation with a pilot For Radio Configurations 3 through 6, the Reverse Dedicated Control Channel and Reverse Fundamental Channel also allow a 9600 bps, 5 ms format. Table 5 Reverse CDMA Channels Received at the Base Station REVERSE CDMA CHANNEL (1.25 MHz or 5 MHz channel received by base station) Reverse Reverse Reverse Enhanced Access Traffic Common Dedicated Access Channel Channel Control Channel Channel (RC 1 or 2) Channel (RC 3 to 6) Reverse Reverse Reverse Reverse Fundamental Pilot Channel Pilot Channel Pilot Channel Channel 0 to 7 Reverse 0 or 1 Reverse Enhanced Access Reverse Common Supplemental Dedicated Control Channel Control Channel Code Channels Channel 0 or 1 Reverse Fundamental Channel 0 to 2 Reverse Supplemental Channels Power Control Subchannel Fig 52.1) Reverse Link Physical Layer Characteristics 2.1.1) Continuous Waveform ١٥
  • 16. Mobile Evolution to 3G The cdma2000 system provides a continuous waveform for all data rates. This includes a continuous pilot and continuous data-channel waveforms. This continuous waveform minimizes biomedical interference to devices such as hearing aids and pacemakers. It also permits a range increase at lower transmission rates. The continuous waveform also enables the interleaving to be performed over the entire frame, rather than just thePortions that are not gated off. This enables the interleaving to achieve the fullbenefit of the frame time diversity. The base station uses the pilot for multipathsearches, tracking, coherent demodulation, and to measure the quality of the linkfor power-control purposes. The cdma2000 system uses separate orthogonal channels for the pilot and each of the data channels. Hence, the relative levels of the Pilot and the physical data channels can easily be adjusted without changing the frame structure or power levels of some symbols of a frame. Also, this flexibility is provided with no performance degradation relative to an approach where the pilot is only sent in short bursts. 2.1.2) Orthogonal Channels Provided Using Different Length Walsh Sequences (OVSF)The cdma2000 system uses orthogonal channels for the Pilot and the otherphysical data channels. Using different length Walsh sequences, with the higherrate channels using shorter Walsh sequences provides these orthogonal channels.Short Walsh sequences allow high encoder output rates to be accommodated. Thecdma2000 system takes advantage of this by using a low code rate. Thechannelization codes are orthogonal variable spreading factor (OVSF) codes thatpreserve the orthogonality between a users different physical channels and supportmultiple data rates. To generate an orthogonal set of functions, the Walsh and ١٦
  • 17. Mobile Evolution to 3GHadamard sequences make useful sets for wireless-CDMA. Walsh functions aregenerated by mapping codeword rows of special square matrices called HadamardMatrices. The Hadamard matrix of desired length can be generated by thefollowing recursive procedure:The OVSF codes can be generated using code tree below:The generated codes of the same layer form a set of Walsh functions and they areorthogonal. Also, any two codes of different layers are orthogonal except for thecase that one of the two codes is a mother code of the other. We can choose an ١٧
  • 18. Mobile Evolution to 3Gappropriate spreading code according to the transmission rate. However, a code inthe code tree can be used by a mobile station iff no other code on the path from thespecific code to the root of the tree or in the subtree below the specific code isused by the same mobile station. Thus, the information signal Xk (t) is firstlycoded by the channelization code Cok and subsequently scrambled by ascrambling code Cs. All the channels of one cell use the same scrambling codewhereas; the different cells use different, distinct scrambling codes. Use of twocodes in two steps is referred to as Multiple spreading. Similarly, for the uplink,each mobile requires a channelization code for transmission to the base station in aserving cell. Further, a distinct scrambling code is assigned to each mobile. Thus,all the mobiles in a cell have a common set of Channelization codes and aseparate, distinguished scrambling code.Both in the uplink and downlink, the scrambling operation is complex .Thiscomplex scrambling is used to equalize the power levels in the I and Q channelsbecause unequal power levels result in a strange constellation. Mathematically,complex scrambling performs the multiplication of two complex signals: thecomplex signal Ic+jQc which is already spread using channelization code and thecomplex scrambling signal Is+jQs. ١٨
  • 19. Mobile Evolution to 3GThus, the amplitude of the resulting signal I + jQ is the product of amplitude ofboth the signals and phase is the sum of their phase. So, when the two channels (Iand Q) have unequal amplitudes, the amplitude of the resulting constellation isalso constant.The family of scrambling codes : Maximal length PN sequences (m-sequence): The long PN codes used in wireless CDMA are of period N= 2^42-1with feedback characteristic polynomial to be X41+X3+1 .These long codes aretruncated to form a cycle of 2^15 bits for its implementation as a scrambling code.The truncated sequences are selected through computer simulation. Extensivesearch is required for the sequences with minimum cross-correlation values.1) DIRECT SEQUENCE SPREADING CAN BE DONE AT BOTH BASESTATION AND MOBILE STATION ١٩
  • 20. Mobile Evolution to 3GUPLINK SPREADING WITH MORE DETAILS ٢٠
  • 21. Mobile Evolution to 3G2) MULTICARRIER SPREADING ONLY AT BASE STATIONVariable data rate capacity, essential for next generation mobile communicationsystems, is achieved by using orthogonal channelization codes. Two-step multiplespreading provides flexibility and distinguishability amongst all users (uplink & ٢١
  • 22. Mobile Evolution to 3Gdownlink), while complex scrambling helps in equalizing power in the I & Qbranches 2.1.3) Rate Matching The cdma2000 system uses several approaches to match the data rates to the Walsh spreader input rates. These include adjusting the code rate, using puncturing, symbol repetition, and sequence repetition. The general design approach is to first try to use a low rate code, but to not reduce the rate below R = 1/4 since the gains of smaller rates would be small and the decoder implementation complexity would increase. 2.1.4) Low Spectral SidelobesThe cdma2000 system achieves low spectral sidelobes with non-ideal mobilepower amplifiers by splitting the physical channels between the in-phase (I) andquadrature (Q) data channels and by using a complex-multiply-type PN spreadingapproach. 2.1.5) Independent Data Channels The cdma2000 system provides two types of physical data channels (Fundamental and Supplemental) on the reverse link that can each be adapted to a particular type of service. The use of Fundamental and Supplemental Channels enables the system to be optimized for multiple simultaneous services. These channels are separately coded and ٢٢
  • 23. Mobile Evolution to 3G interleaved and may have different transmit power levels and frame error rate set points. Each channel carries different types of services depending on the service scenarios. 2.1.6) Power-Control 2.1.6.1) Reverse Power Control DONE FOR MS.There are three components of reverse power control: open loop, closed loop, andouter loop. Open loop power control sets the transmit power based upon the powerthat is received at the mobile station. Open loop power control compensates for thepath loss from the mobile station to the base station and handles very slow fading.Closed loop power control consists of an 800 bps feedback loop from the basestation to the mobile station to set the transmit power of the mobile station. Closedloop power control compensates for medium to fast fading and for inaccuracies inopen loop power control. Outer loop power control is implementation specific but typically adjusts the closed loop power control threshold in the base station in order to maintain a desired frame error rate. 2.1.6.2) Forward Power Control DONE FOR BS. The power of the forward link channels for a specific user is adjusted at a rate of 800 bits per second. The forward power control information is time-multiplexed with the reverse link pilot. 2.1.7) Separate Dedicated Control Channel ٢٣
  • 24. Mobile Evolution to 3G The cdma2000 reverse link includes a separate low rate, low power, continuous, orthogonal, Dedicated Control Channel. This allows for a flexible Dedicated Control Channel structure that does not impact the other pilot and physical channel frame structures. 2.1.8) Frame LengthThe cdma2000 system supports 5 and 20 ms frames for control information on theFundamental and Dedicated Control Channels, and uses 20 ms frames for othertypes of data (including voice). Interleaving and sequence repetitions are over theentire frame interval. This provides improved time diversity over systems that useshorter frames.The 20 ms frames are used for voice. A shorter frame would reduce onecomponent of the total voice delay, but degrade the demodulation performancedue to the shorter interleaving span. 2.1.9) Direct-Spread Chip RateThe cdma2000 system uses a chip rate that is a multiple of the TIA/EIA-95-B chiprate of 1.2288 Mcps, and nominal channel spacing that are a multiple of 1.25MHz. This channel spacing provides a flexible and convenient spacing for carrierfrequency allocations of 5, 10, 15, and 20 MHz.2.2) Reverse Link Modulation and Coding The cdma2000 reverse link uses direct-sequence spreading with the TIA/EIA-95-B chip rate of 1.2288 Mcps (denoted as a 1X chip rate) or chip rates that are 3, 6, 9, or 12 times the TIA/EIA-95-B chip rate. Higher ٢٤
  • 25. Mobile Evolution to 3Gchip rate systems are denoted as 3X, 6X, 9X, and 12X and they arerespectively operated at 3.6864, 7.3728, 11.0592, and 14.7456 Mcps.The 1X system can be used anywhere that a TIA/EIA-95-B reverse link isused. An IA/EIA-95-B reverse link carrier frequency can also be sharedwith mobiles transmitting the TIA/EIA-95-B waveform and thosetransmitting the 1X cdma2000 waveform. The higher chip rate reverselinks can be used in applications where larger bandwidth allocations areavailable. Mobiles that support a higher chip rate would typically alsosupport the 1X chip rate. This will allow these mobiles to access basestations that only support the 1X chip rate and allow operators with largerbandwidth allocations the flexibility of using a mixture of 1X and higherchip rate systems.Within an operator’s allocated band, the 1X cdma2000 reverse linkswould typically occupy the same bandwidth as TIA/EIA-95-B reverselink systems (i.e., 1.25 MHz) and higher chip rate cdma2000 links wouldtypically occupy a bandwidth that is 1.25 MHzTimes the higher chip rate factor. A guard band of 1.25 MHz/2 = 625 kHzwould typically be used on both sides of the operator’s allocated band.The Reverse CDMA Channel is composed of Reverse Common Channelsand Reverse Dedicated Channels.The mobile station to initiate communications with the base station and torespond to Forward Link Paging Channel messages uses the ReverseCommon Channel. The Reverse Common Channel uses a random-accessprotocol. Reverse Common Channels are uniquely identified by their longcode. ٢٥
  • 26. Mobile Evolution to 3G The Reverse Dedicated Channel may be used for the transmission of user traffic, control, and signaling information to the base station.2.3) Reverse Dedicated Channel 2.3.1) Walsh and PN Spreading Reverse Dedicated Channels consist of up to several physical channels: a Reverse Pilot Channel, which is always used, and a Reverse Fundamental Channel (R-FCH), one or more Reverse Supplemental Channels (R-SCH), and a Reverse Dedicated Control Channel (R-DCCH). The R-FCH, R-SCH, R-DCCH may or may not be used depending on the service scenario. Each physical channel is spread with a Walsh code sequence to provide orthogonal channelization among these physical channels. The spread Pilot and R- DCCH are mapped to the in-phase (I) data channel. The spread R-FCH and R-SCH are mapped to the quadrature (Q) data channel. Then, the I and Q data channels are Spread using a complex-multiply PN spreading approach. Figure 9.6 shows this Reverse Dedicated Channel structure. The Supplemental Channel (R-SCH) is spread using a two bit Walsh function. Optionally two Supplemental Channels (denoted as R-SCH1 and R-SCH2 on Figure 9.6) can be accommodated to support bearer service profiles where more than one R-SCH is needed. In that case both Supplemental Channels are spread using a four bit Walsh functions (reducing the maximum supported data rate of each Supplemental for 1X, ٢٦
  • 27. Mobile Evolution to 3G3X, and 6X). R-SCH1 is mapped to the I Channel and R-SCH2 is mappedto the Q channel.Additional Supplemental Channels can be accommodated by increasingthe Walsh length for Supplemental Channel to 8 bits and mappingadditional R-SCHs to the I and Q channel.The quadrature direct-sequence spreading uses the TIA/EIA-95-BI-channel and Q-channel PN sequences. These sequences have a period of2^15 chips. So for the 1X chip rate they repeat 75 times in 2 seconds(i.e., once every 26.66 ms).The TIA/EIA-95-B long code, with a period of 2^42 – 1 chips, is used forall of the chip rates. ٢٧
  • 28. Mobile Evolution to 3G Reverse Dedicated Channel Walsh Cover (+ + – – ) or (+ + – – – – + +) Complex Multiplier Reverse Relative Supplemental C Gain Channel 2 + + Reverse + Baseband Pilot A Σ Σ Filter Channel + – Reverse Relative Dedicated B cos(2π fct) Gain Control Channel Walsh Cover Σ Gain s(t) (+ + + + + + + + – – – – – – – – ) Reverse Relative Fundamental C Gain Channel + + Baseband Walsh Cover Σ Σ Filter Reverse (+ + + + – – – – + + + + – – – – ) + + Supplemental Channel 1, Reverse Relative C sin(2π fct) Common Control GainChannel, or Enhanced Access Channel Walsh Cover Walsh Cover (+ – ) or (+ + – – ) (+ – ) Notes : for Reverse Supplemental Channel 1. Binary signals are represented with ± 1 values (+ + + + – – – – ) with the mapping +1 for ‘0’ and –1 for ‘1’. for Reverse Common Control Channel Unused channels and gated-off symbols are Decimator and Enhanced Access Channel represented with zero values. by Factor 2. When the Reverse Common Control Channel or of 2 Enhanced Access Channel is used, the only additional channel is the Reverse Pilot Channel. 3. All of the pre-baseband-filter operations occur I-Channel Q-Channel at the chip rate. PN Sequence PN Sequence 1-Chip Delay Long Long Code Code Mask Generator Fig 6Figure 6 shows the physical channels separated by orthogonal Walshfunctions and the I and Q channel in phase quadrature. The I data channeland the Q data channel are labeled as DI and DQ, respectively.The Reverse Pilot Channel is used for initial acquisition, time tracking,Rake-receiver coherent reference recovery, and power-controlmeasurements. The levels of the Fundamental, Supplemental, andDedicated Control Channels are adjusted relative to the Reverse PilotChannel by using the gains GF, GS, and GC. These are slow adjustmentsto adapt to different coding and interleaving and to adapt to differentpropagation conditions. ٢٨
  • 29. Mobile Evolution to 3G2.3.2) Reverse Pilot Channel (R-PICH) The Pilot Channel for the Reverse Dedicated Channels consists of a fixed reference value and multiplexed forward Power-Control (PC) information as illustrated in Figure 34. This time multiplexed forward Power Control information is referred to as the power control sub-channel. This sub- channel provides information on the quality of the forward link at the rate of 1 bit per 1.25 ms Power-Control Group (PCG) and is used by the forward link channels to adjust their power. The power-control symbol repetition means that the 1-bit value is constant for that repeated-symbol duration. The power-control bit uses the last portion of each power- control group. The +1 pilot symbols and the multiplexed power-control symbols are all sent with the same power level. The binary power-control symbols are represented with ±1 values in Figure 7. Gating Rate 1.25 ms 1 Pilot PC 1/2 1/4 5 ms 20 ms Fig 79.2.3.3) Reverse Fundamental Channel (R-FCH) ٢٩
  • 30. Mobile Evolution to 3G Figure 6, Figure 7, and Figure 8 describe the modulation for the Reverse Fundamental Channel (R-FCH). This channel supports 5 and 20 ms frames. The 20 ms frame structures provide rates derived from the TIA/EIA-95-B Rate Set 1 or Rate Set 2 rate sets. The 5 ms frames provide 24 information bits per frame with a 16-bit CRC. Within each 20 ms frame interval, either one 20 ms R-FCH structure, up to four 5 ms R-FCH structure(s), or nothing can be transmitted.2.3.4) Reverse Supplemental Channel (R-SCH) The Supplemental Channel (R-SCH) can be operated in two distinct modes as shown on Figure 6. The first mode is used for data rates not exceeding 14.4 kbps. In the second mode, the base station explicitly knows the rate information. In the first mode, the variable rates provided are those derived from the TIA/EIA-95-B Rate Set 1 (RS1) and Rate Set 2 (RS2). The structures for the variable-rate modes are identical to the 20 ms Reverse Fundamental Channel (R-FCH) structures followed by a 2-symbol repetition factor. This repetition factor compensates for the shorter Walsh sequence of the R-SCH compared to that of the R-FCH. When two Supplemental Channels are used (R-SCH1 and R-SCH2) each Supplemental Channel is spread using a four bit Walsh sequence. Since the R-FCH is also spread by a four bit Walsh sequence, the 2 symbol repetition factor is removed in the case when two Supplemental Channels are being used. ٣٠
  • 31. Mobile Evolution to 3G In the second mode, the high data rate modes can have convolutional coding with K = 9, or turbo coding with two K = 4 component encoders. Figure11, Figure 12, Figure 13, Figure 14, and Figure 15 give the R-SCH structures for the high data rate modes with K = 9 convolutional coding and 1X, 3X, 6X, 9X, and 12X chip rates. With turbo coding, the structures are changed as follows:• The K = 9 encoder is replaced by a turbo encoder with the same basic (before puncturing) rate.• The 8-bit encoder tail is replaced by a 6-bit encoder tail.• Two reserved bits are added after the 6-bit encoder tail to keep the number of information bits constant regardless of the encoding method. Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 3 Channel Bits Add Add 8 Convolutional Frame Reserved/ Symbol Symbol Block or Turbo C Quality Encoder Repetition Puncture Interleaver Encoder Indicator Tail Bits Bits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/4 2× None 384 76.8 16 6 1.5 1/4 16× 1 of 5 1,536 76.8 40 6 2.7 1/4 8× 1 of 9 1,536 76.8 80 8 4.8 1/4 4× None 1,536 76.8 172 12 9.6 1/4 2× None 1,536N 76.8 360 16 19.2 1/4 1× None 1,536N 76.8 744 16 38.4 1/4 1× None 3,072N 153.6 1,512 16 76.8 1/4 1× None 6,144N 307.2 3,048 16 153.6 1/4 1× None 12,288N 614.4 6,120 16 307.2 1/2 1× None 12,288N 614.4 Notes: 1. The 5 ms frame is only used for the Reverse Fundamental Channels, and only rates of 9.6 kbps or less are used for Reverse Fundamental Channels. 2. Turbo coding may be used for the Reverse Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Table 6 Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 4 ٣١
  • 32. Mobile Evolution to 3G Channel Bits Add Add 8 Add Convolutional Frame Reserved/ Symbol Symbol Block Reserved or Turbo C Quality Encoder Repetition Puncture Interleaver Bits Encoder Indicator Tail Bits Bits/Frame Bits Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 0 16 9.6 1/4 2× None 384 76.8 21 1 6 1.8 1/4 16× 8 of 24 1,536 76.8 55 1 8 3.6 1/4 8× 8 of 24 1,536 76.8 125 1 10 7.2 1/4 4× 8 of 24 1,536 76.8 267 1 12 14.4 1/4 2× 8 of 24 1,536N 76.8 552 0 16 28.8 1/4 1× 4 of 12 1,536N 76.8 1,128 0 16 57.6 1/4 1× 4 of 12 3,072N 153.6 2,280 0 16 115.2 1/4 1× 4 of 12 6,144N 307.2 4,584 0 16 230.4 1/4 1× 4 of 12 12,288N 614.4 Notes: 1. The 5 ms frame is only used for the Reverse Fundamental Channels, and only rates of 14.4 kbps or less are used for Reverse Fundamental Channels. 2. Turbo coding may be used for the Reverse Supplemental Channels with rates of 28.8 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Table 7Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 5 Channel Bits Add Add 8 Convolutional Frame Reserved/ Symbol Symbol Block or Turbo C Quality Encoder Repetition Puncture Interleaver Encoder Indicator Tail Bits Bits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/4 2× None 384 76.8 16 6 1.5 1/4 16× 1 of 5 1,536 76.8 40 6 2.7 1/4 8× 1 of 9 1,536 76.8 80 8 4.8 1/4 4× None 1,536 76.8 172 12 9.6 1/4 2× None 1,536N 76.8 360 16 19.2 1/4 1× None 1,536N 76.8 744 16 38.4 1/4 1× None 3,072N 153.6 1,512 16 76.8 1/4 1× None 6,144N 307.2 3,048 16 153.6 1/4 1× None 12,288N 614.4 6,120 16 307.2 1/3 1× None 18,432N 921.6 12,264 16 614.4 1/3 1× None 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Reverse Fundamental Channels, and only rates of 9.6 kbps or less are used for Reverse Fundamental Channels. 2. Turbo coding may be used for the Reverse Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Table8 ٣٢
  • 33. Mobile Evolution to 3G Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 6 Channel Bits Add Add 8 Add Convolutional Frame Reserved/ Symbol Symbol Block Reserved or Turbo C Quality Encoder Repetition Puncture Interleaver Bits Encoder Indicator Tail Bits Bits/Frame Bits Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 0 16 9.6 1/4 2× None 384 76.8 21 1 6 1.8 1/4 16× 8 of 24 1,536 76.8 55 1 8 3.6 1/4 8× 8 of 24 1,536 76.8 125 1 10 7.2 1/4 4× 8 of 24 1,536 76.8 267 1 12 14.4 1/4 2× 8 of 24 1,536N 76.8 552 0 16 28.8 1/4 1× None 2,304N 115.2 1,128 0 16 57.6 1/4 1× None 4,608N 230.4 2,280 0 16 115.2 1/4 1× None 9,216N 460.8 4,584 0 16 230.4 1/4 1× None 18,432N 921.6 9,192 0 16 460.8 1/4 1× None 36,864N 1,843.2 20,712 0 16 1,036.8 1/2 1× 2 of 18 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Reverse Fundamental Channels, and only rates of 14.4 kbps or less are used for Reverse Fundamental Channels. 2. Turbo coding may be used for the Reverse Supplemental Channels with rates of 28.8 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Table 92.3.5) Reverse Common Channel The Reverse Access Channel (R-ACH) and the Reverse Common Control Channel (R-CCCH) are common channels used for communication of messages from the mobile station to the base station. The R-CCCH differs from the R-ACH in that the R-CCCH offers extended capabilities beyond the Reverse Access Channel (R-ACH). The R-ACH and R-CCCH are multiple access channels as mobile stations transmit without explicit authorization by the base station. The Reverse Access Channel and Reverse Common Control Channel use a slotted Aloha type of mechanisms with higher capture probabilities due to the CDMA properties of the channel (simultaneous transmission of multiple users). ٣٣
  • 34. Mobile Evolution to 3G There can be one or more access channels per frequency assignment. Different access channels are distinguished by different long codes. The Reverse Common Control Channel (R-CCCH) uses a physical structure similar to the Reverse Access Channel (R-ACH). The main difference between the R-CCCH and the R-ACH is in the addition of frame sizes of 5 and 10 ms as well as data rates of 19.2 and 38.4 kbps. The R-CCCH may use the same long codes as the R-ACH or they may use different long codes. .2.4) Access Channel The Access Channel is used by the mobile station to initiate communication with the base station and to respond to Paging Channel messages. An Access Channel transmission is a coded, interleaved, and modulated spread-spectrum signal. The Access Channel uses a random- access protocol. Access Channels are uniquely identified by their long codes. The mobile station shall transmit information on the Access Channel at a fixed data rate of 4800 bps. An Access Channel frame shall be 20 ms in duration. An Access Channel frame shall begin only when System Time is an integral multiple of 20 ms. The Reverse CDMA Channel may contain up to 32 Access Channels numbered 0 through 31 per supported Paging Channel. At least one Access Channel exists on the Reverse CDMA Channel for each Paging Channel on the corresponding Forward CDMA Channel. Each Access Channel is associated with a single Paging Channel. ٣٤
  • 35. Mobile Evolution to 3GEach Access Channel frame contains 96 bits (20 ms frame at 4800 bps).Each Access Channel frame shall consist of 88 information bits and eightEncoder Tail Bits (see Figure 8). The channel structure for spreadingrate1 is shown in figure. Access Channel Frame Structure 96 bits (20ms) 4800 bps 88 8 Frame Information Bits T Notation T - Encoder Tail Bits Channel Structure for the Header on the Enhanced Access Channel for spreading Rate 1 fig. 8 Access Repeated Channel Code Code Bits Add 8 Convolutional Symbol Symbol Symbol Encoder Encoder 4.8 kbps Repetition 28.8 ksps 88 Bits/Frame Tail Bits R = 1/3, K = 9 (4.4 kbps) Block Repeated Modulation Symbol Code Symbol 64-ary (Walsh Chip) Interleaver Orthogonal (576 28.8 ksps 4.8 ksps Modulator Symbols) (307.2 kcps) Long Long Code Code Mask 1.2288 Mcps Generator I-Channel PN Sequence cos(2π fct) Signal Point I Mapping Channel Baseband 0 → +1 Gain Filter 1 → –1 s(t) Σ Signal Point Q 1/2 PN Mapping Channel Baseband Chip 0 → +1 Gain Filter Delay 1 → –1 Q-Channel sin(2π fct) PN Sequence Fig 9 ٣٥
  • 36. Mobile Evolution to 3GThe Access Channel preamble shall consist of frames of 96 zeros that aretransmitted at the 4800 bps rate. The Access Channel preamble istransmitted to aid the base station in acquiring an Access Channeltransmission.2.4.1) Enhanced Access ChannelThe Enhanced Access Channel is used by the mobile station to initiatecommunication with the base station or to respond to a mobile stationdirected message. The Enhanced Access Channel can be used in one ofthree possible modes: Basic Access Mode, Power Controlled AccessMode, and Reservation Access Mode.When operating in the Basic Access Mode, the mobile station shall nottransmit the Enhanced Access header on the Enhanced Access Channel.In Basic Access Mode, the access probe shall consist of an EnhancedAccess Channel preamble, followed by Enhanced Access data.When operating in the Power Controlled Access Mode, the EnhancedAccess Channel probe shall consist of an Enhanced Access Channelpreamble, followed by an Enhanced Access header and Enhanced Accessdata.When operating in the Reservation Access Mode, the Enhanced AccessChannel probe shall consist of an Enhanced Access Channel preamble,followed by an Enhanced Access header. Enhanced Access data is sent onthe Reverse Common Control Channel upon receiving permission fromthe base station. ٣٦
  • 37. Mobile Evolution to 3GThe Enhanced Access Channel uses a random-access protocol. EnhancedAccess Channels are uniquely identified by their long codes. TheEnhanced Access Channel probe structure is shown in Figure 9.10 Enhanced Access Channel Probe StructureTx Power Enhanced Access Not transmitted in Not transmitted in Channel Preamble Basic Access Mode Reservation Access Mode Preamble Reverse Pilot Channel Enhanced Enhanced Enhanced Access Access Header Access Data Header Enhanced Access Data Preamble Transmission (See Figure 2.1.3.4.2.3-1) Reverse Pilot Channel Transmission 1.25 ms 5 ms (1 to RACH_MAX_CAP_SZ) x 5 ms Fig 10The mobile station shall transmit the Enhanced Access header on theEnhanced Access Channel at a fixed data rate of 9600 bps. The mobilestation shall transmit the Enhanced Access data on the Enhanced AccessChannel at a fixed data rate of 9600, 19200, or 38400 bps.The frame duration for the Enhanced Access header on the EnhancedAccess Channel shall be 5 ms in duration. The frame duration for theEnhanced Access data on the Enhanced Access Channel shall be 20, 10,or 5 ms in duration. ٣٧
  • 38. Mobile Evolution to 3G An Enhanced Access Channel frame of 20, 10, or 5 ms duration shall begin only when System Time is an integral multiple of 20, 10, or 5 ms respectively. The Reverse CDMA Channel may contain up to 32 Enhanced Access Channels per Forward Common Control Channel supported, numbered 0 through 31. There is a Forward Common Assignment Channel associated with every Enhanced Access Channel operating in the Power Controlled Access Mode or the Reservation Access Mode. Table 10 summarizes the Enhanced Access Channel bit allocations. Enhanced Access Channel Frame Structure Summary Number of Bits per Frame Frame Frame Frame Transmissio Total Informatio Encoder QualityLength (ms) Type n Rate (bps) Bits n Bits Tail Bits Indicator 5 Header 9600 48 32 8 8 20 Data 9600 192 172 12 8 20 Data 19200 384 360 16 8 20 Data 38400 768 744 16 8 10 Data 19200 192 172 12 8 10 Data 38400 384 360 16 8 5 Data 38400 192 172 12 8 Table10 Enhanced Access Channel header frames shall consist of 48 bits. These 48 bits shall be composed of 32 information bits followed by eight frame quality indicator (CRC) bits and eight Encoder Tail Bits, as shown in ٣٨
  • 39. Mobile Evolution to 3GEnhanced Access Channel Frame Structure for the Enhanced AccessHeader 48 bits (5ms) 9600 bps 32 8 8 Frame Information Bits F T Notation F - Frame Quality Indicator (CRC) T - Encoder Tail Bits Fig 11 Channel Structure for the Header on the Enhanced Access Channel for Spreading Rate 1 Modulation Enhanced Add 8-Bit Block Symbols Add 8 Convolutional Symbol Access Frame Interleaver Encoder Encoder Repetition C Channel Quality (768 Tail Bits R = 1/4, K = 9 (4× Factor) Bits Indicator Symbols) 32 Bits per 9.6 kbps 153.6 ksps 5 ms Frame Fig.12 Channel for the Header on the Enhanced Access Channel for Spreading Rate 3 Enhanced Add 8-Bit Block Add 8 Convolutional Symbol Access Frame Interleaver Encoder Encoder Repetition C Channel Quality (768 Tail Bits R = 1/4, K = 9 (4× Factor) Bits Indicator Symbols) 32 Bits per 9.6 kbps 153.6 ksps 5 ms Frame Fig 13 ٣٩
  • 40. Mobile Evolution to 3G Enhanced Access Channel Frame Structure 192 bits (20ms) 9600 bps 172 12 8 Frame Information Bits F T 384 bits (20ms) 19200 bps 360 16 8 Frame Information Bits F T 768 bits (20ms) 38400 bps 744 16 8 Frame Information Bits F T 192 bits (10ms) 19200 bps 172 12 8 Frame Information Bits F T 384 bits (10ms) 38400 bps 360 16 8 Frame Information Bits F T 192 bits (5ms) 38400 bps 172 12 8 Frame Information Bits F T Notation F - Frame Quality Indicator (CRC) T - Encoder Tail Bits Fig 14 ٤٠
  • 41. Mobile Evolution to 3GI and Q Mapping for Enhanced Access Channel, Reverse Common Control Channel, and Reverse Traffic Channel with Radio Configurations 3 and 4 Walsh Cover (+ + – – ) or (+ + – – – – + +) Complex Multiplier Reverse Relative Supplemental C Gain Channel 2 + + Reverse + Baseband Pilot A Σ Σ Filter Channel + – Reverse Relative Dedicated B cos(2π fct) Gain Control Channel Walsh Cover Σ Gain s(t) (+ + + + + + + + – – – – – – – – ) Reverse Relative Fundamental C Gain Channel + + Baseband Walsh Cover Σ Σ Filter Reverse (+ + + + – – – – + + + + – – – – ) + + Supplemental Channel 1, Reverse Relative C sin(2π fct) Common Control Gain Channel, or Enhanced Access Channel Walsh Cover Walsh Cover (+ – ) or (+ + – – ) (+ – ) Notes : for Reverse Supplemental Channel 1. Binary signals are represented with ± 1 values (+ + + + – – – – ) with the mapping +1 for ‘0’ and –1 for ‘1’. for Reverse Common Control Channel Unused channels and gated-off symbols are Decimator and Enhanced Access Channel represented with zero values. by Factor 2. When the Reverse Common Control Channel or of 2 Enhanced Access Channel is used, the only additional channel is the Reverse Pilot Channel. 3. All of the pre-baseband-filter operations occur I-Channel Q-Channel at the chip rate. PN Sequence PN Sequence 1-Chip Delay Long Long Code Code Mask Generator Fig15 Channel Structure for the Data on the Enhanced Access Channel and the Reverse Common Control Channel for Spreading Rate 1 Modulation Reverse Symbols Add Common Add 8 Convolutional Frame Symbol Block Control Encoder Encoder C Quality Repetition Interleaver Channel Tail Bits R = 1/4, K = 9 Indicator Bits Bits/Frame Bits Rate (kbps) Factor Symbols Rate (ksps) 172 (5 ms) 12 38.4 1× 768 153.6 360 (10 ms) 16 38.4 1× 1,536 153.6 172 (10 ms) 12 19.2 2× 1,536 153.6 744 (20 ms) 16 38.4 1× 3,072 153.6 360 (20 ms) 16 19.2 2× 3,072 153.6 172 (20 ms) 12 9.6 4× 3,072 153.6 Fig 16 ٤١
  • 42. Mobile Evolution to 3G Channel Structure for the Data on the Enhanced Access Channel and the Reverse Common Control Channel for Spreading Rate 3 Reverse Add Common Add 8 Convolutional Frame Symbol Block Control Encoder Encoder C Quality Repetition Interleaver Channel Tail Bits R = 1/4, K = 9 Indicator Bits Bits/Frame Bits Rate (kbps) Factor Symbols Rate (ksps) 172 (5 ms) 12 38.4 1× 768 153.6 360 (10 ms) 16 38.4 1× 1,536 153.6 172 (10 ms) 12 19.2 2× 1,536 153.6 744 (20 ms) 16 38.4 1× 3,072 153.6 360 (20 ms) 16 19.2 2× 3,072 153.6 172 (20 ms) 12 9.6 4× 3,072 153.6 Fig 17The last eight bits of each Enhanced Access Channel frame are called theEncoder Tail Bits. These eight bits shall be set to ‘0’.Each transmission on the R-ACH or R-CCCH (denoted as an accessprobe) consists of an Access Preamble and an Access Channel MessageCapsule. The Access Preamble is a transmission of only the non-databearing Reverse Pilot Channel (R-PICH) at an increased power level; theAccess Channel Message Capsule transmission consists of the databearing R-ACH or R-CCCH and the associated, non-data bearing ReversePilot Channel.2.4.2) Reverse Pilot Channel and the Access PreambleThe Reverse Pilot Channel associated with the Reverse Access Channelor Reverse Common Control Channel has a similar structure to theReverse Pilot Channel used when the mobile station is communicatingwith the base station in a dedicated mode. The key difference is that theReverse Pilot Channel associated with the Reverse Access Channels doesnot have a Power Control sub-channel and therefore no Power Controlbits are time-multiplexed with the Reverse Pilot Channel. The Reverse ٤٢
  • 43. Mobile Evolution to 3GPilot Channel associated with the Reverse Access Channels consists of anall ‘0’ channel.The Access preamble consists of transmissions only on the Reverse PilotChannel. The preamble length is an integer number of 1.25 ms intervals.A zero length preamble (no preamble) is permitted. The number of 1.25ms intervals to be used is indicated by the base station. The preamblelength depends upon the rate at which the base station can search the PNspace, the cell radius, and the multipath characteristics of the cell.The base station search rate is dependent upon the hardware configurationof the cell. When more possible PN hypotheses can be searched inparallel, then the base station can acquire the mobile station faster.Similarly, when the cell radius is larger, the number of PN hypothesesincreases. In addition, different multipath conditions may makecombining losses higher or have more fading, resulting in moreaccumulations being required for a given probability of detection.The preamble for the R-ACH and R-CCCH is transmitted at a specifiedpower setting stronger than the Reverse Pilot Channel depending upondata rate and mobile station power limitations. If the mobile station mustreduce its R-ACH or R-CCCH transmission rate due to insufficient outputpower, then the mobile station transmits the preamble(as well as the access probe itself) at the maximum available power. ٤٣
  • 44. Mobile Evolution to 3G2.5) Slotting and Channel Arrangement Access probe transmissions are slotted. The slot is long enough to accommodate the preamble and the longest message. The base station indicates the slot length. The transmission must begin at the beginning of the slot; the transmission is not required to last any longer than the number of frames required to transmit the message. To reduce delay, the slotting for different access channels can be offset. The acquisition process is substantially simpler due to the system slotted design. The base station attempts to acquire mobile station at the beginning of slots, during the time in which the mobile station would send the acquisition preamble. 2.5.1) Reverse Common Control Channel The Reverse Common Control Channel is used for the transmission of user and signaling information to the base station when Reverse Traffic Channels are not in use. A Reverse Common Control Channel transmission is a coded, interleaved, and modulated spread-spectrum signal. The mobile station transmits during intervals specified by the base station. Reverse Common Control Channels are uniquely identified by their long codes. The Reverse Common Control Channel preamble and data transmission structure is shown in Figure 18. ٤٤
  • 45. Mobile Evolution to 3G Preamble and Data Transmission for the Reverse Common Control Channel Tx Power Preamble Reverse Pilot Reverse Common Control Channel Channel Transmission Reverse Common Control Channel Preamble Transmission (See Figure 2.1.3.5.2.3-1) Reverse Pilot Channel Transmission 1.25 ms 20, 10, or 5 ms Reverse Common Reverse Common Control Channel Control Channel Data Preamble Fig 18The mobile station shall transmit information on the Reverse CommonControl Channel at variable data rates of 9600, 19200, and 38400 bps. AReverse Common Control Channel frame shall be 20, 10, or 5 ms induration. A Reverse Common Control Channel frame of 20, 10, or 5 msduration shall begin only when System Time is an integral multiple of 20,10, or 5 ms respectively.The Reverse CDMA Channel may contain up to 32 Reverse CommonControl Channels numbered 0 through 31 per supported ForwardCommon Control Channel. At least one Reverse Common ControlChannel exists on the Reverse CDMA Channel for each ForwardCommon Control Channel on the corresponding Forward CDMA ٤٥
  • 46. Mobile Evolution to 3GChannel. Each Reverse Common Control Channel is associated with asingle Forward Common Control Channel.Table 11 summarizes the Reverse Common Control Channel bitallocations.All frames shall consist of the information bits, followed by a framequality indicator (CRC) and eight Encoder Tail. Reverse Common Control Channel Frame Structure Summary Number of Bits per Frame Frame Transmission Frame Encoder Length Rate Total Information Quality Tail Bits (ms) (bps) Indicator 20 9600 192 172 12 8 20 19200 384 360 16 8 20 38400 768 744 16 8 10 19200 192 172 12 8 10 38400 384 360 16 8 5 38400 192 172 12 8 Table 11The last eight bits of each Reverse Common Control Channel frame arecalled the Encoder Tail Bits. These eight bits shall be set to ‘0’.The Reverse Common Control Channel preamble is transmitted to aid thebase station in acquiring a Reverse Common Control Channeltransmission.The Reverse Common Control Channel preamble is shown inFigure 19. The Reverse Common Control Channel preamble is a ٤٦
  • 47. Mobile Evolution to 3Gtransmission of only the non-data-bearing Reverse Pilot Channel at anincreased power level. The Reverse Pilot Channel associated with theReverse Common Control Channel does not have a power control subchannel. The total preamble length shall be an integer number of 1.25 ms.A zero length preamble (no preamble) is permitted. The ReverseCommon Control Channel preamble shall consist of a sequence offractional preambles and one additional preamble. Preamble for the Reverse Common Control Channel Preamble Transmission (See Figure 2.1.3.5-1) Fractional Fractional Fractional Additional Preamble 1 Preamble 2 Preamble N Preamble P B P P B A T N = RCCCH_PREAMBLE_NUM_FRACs + 1 P = RCCCH_PREAMBLE_FRAC_DURATIONs + 1) * 1.25 ms B = RCCCH_PREAMBLE_OFF_DURATIONs * 1.25 ms A = RCCCH_PREAMBLE_ADD_DURATIONs * 1.25 ms T = N (P + B) + A = RCCCH_PREAMBLE_TOTAL_DURATION * 1.25 ms Fig 199.2.5.2) Reverse Common Channel ProceduresThe procedures for the R-CCCH are essentially the same as the R-ACH. ٤٧
  • 48. Mobile Evolution to 3G9.2.5.3) Access AttemptsThe entire process of sending one message and receiving (or failing toreceive) an acknowledgment for that message on the R-ACH is called anaccess attempt. One access attempt consists of one or more access sub-attempts. Each sub-attempt consists of one or more access probesequences. Each transmission in an access probe sequence is called anaccess probe. The access sub-attempt is shown in more detail in Figure20. ٤٨
  • 49. Mobile Evolution to 3G 2.5.4) Access Probe Sequences Within an access probe sequence, the mobile station transmits at successively higher powers. The first probe of a sequence is transmitted at a power level given by the open loop power level plus two offsets which are indicated to the mobile station by the base station, plus an adjustment for the R-ACH transmission rate. The first offset is the Initial Power (IP) offset which is the nominal offset power that corrects for the open loop power control imbalance between the forward and reverse links. The second offset is the Power Increment (PI). This adjusts the received level at the base station for access probes relative to dedicated channel transmissions. As shown in Figure 20, each successive probe within a probe sequence is transmitted at a level that is PI greater compared to the previous probe (after taking into account the open loop change). The mobile station transmits probes at corresponding higher powers until an acknowledgment is received, a complete sequence of probes is transmitted, it performs an access probe handoff, or it fails the access attempt. The number of probes in a sequence is determined by parameters indicated by the base station. If a complete sequence of probes has been transmitted, then the mobile station can transmit another sequence beginning at the original power setting. The maximum number of sequences is also determined by parameters indicated by the base station.2.6) Access Probe Handoff If the mobile station is unable to receive the forward link or if a neighboring base station is sufficiently strong, the mobile station may ٤٩
  • 50. Mobile Evolution to 3G stop the access probe sequence and perform an access probe handoff. The overhead messages provide the mobile station with the set of base stations to which the mobile station is permitted to perform an access probe handoff. When the mobile station performs an access probe handoff, the mobile station adjusts its receiver, by changing the F-PICH PN offset, to receive the neighboring base station. Depending upon the configuration of the neighboring base station, the mobile station may have to change the code channels or the long codes that it is using. Whether this must be done, and the correct code channels to use, is provided by the overhead messages. When the mobile station performs an access probe handoff, it begins a new access sub-attempt. The overhead messages indicate the maximum number of access sub-attempts that are permitted. Each access sub- attempt also has the mobile station begin a new access probe sequence.2.7) Randomization between Probes and Sequences Because there are collisions (multiple simultaneous transmissions which the bases station cannot simultaneously receive), the time of retransmission should be randomized so that the retransmissions will not collide again. Whenever an acknowledgment is not received to a probe (after a time-out period denoted by TA on Figure 9.20), the mobile station waits a random time, called the probe backoff, before beginning the next access probe. The probe backoff is shown by RT in Figure 20. Between ٥٠
  • 51. Mobile Evolution to 3Gaccess probe sequences, a different random time interval is used (calledthe sequence backoff) which is given by RS in Figure 20.Main blocks in the system physical layer in details:2.7.1) Convolutional Codes :The cdma2000 reverse link uses a K=9, R=1/4 convolutional code for theFundamental Channel (R-FCH). The better codeword distance a propertyof this low rate code provides performance gains versus higher rate codesin fading and Additive White Gaussian Noise (AWGN) channelconditions. The constraint-length K = 9, R = 1/4 convolutional codeprovides a gain of approximately 0.5 dB over a K = 9, R = 1/2 (Used inIS-95) code even in AWGN. The Supplemental Channel (RSCH) usesconvolutional codes for data rates up to 14.4 kbps. Convolutional codesfor higher data rates on the Supplemental Channel are optional and theuse of Turbo codes is preferred. For some of the highest data rates R=1/3and R=1/2 codes are used.The parameters of the convolutional codes used are given in Table 12(polynomials given in octal). Reverse Link Convolutional Codes Polynomials Table 12 Generator Generator Generator Generator ConstraintRate Polynomial Polynomial Polynomial Polynomial Length (K) g0 g1 g2 g3 1/2 9 753 561 N/A N/A 1/3 9 557 663 711 N/A 1/4 9 765 671 513 473 ٥١
  • 52. Mobile Evolution to 3G2.7.2) Turbo CodesA common constituent code is used for reverse link Turbo codes of rate1/4, 1/3, and 1/2 for all Supplemental Channels (R-SCH). The generatorpolynomials for this constituent code are given in Table 13 (polynomialsgiven in octal). Reverse Link Turbo Codes Polynomials Generator Generator Generator ConstraintRate Polynomial d Polynomial n0 Polynomial n1 Length (K) (feedback) (Y0) (Y1) 1/2,1/3,1/4 4 15 13 17 Table 132.7.3) Block InterleavingThe mobile station shall interleave all repeated code symbols andsubsequent puncturing, if used, on the Access Channel, the EnhancedAccess Channel, and the Reverse Common Control Channel, and theReverse Traffic Channel prior to modulation and transmission.For the Reverse Traffic Channel with Radio Configurations 1 and 2, theinterleaver shall be an array with 32 rows and 18 columns (i.e., 576 cells).Repeated code symbols shall be written into the interleaver by columnsfrom the first column to the eighteenth column filling the complete 32matrix. Reverse Traffic Channel repeated code symbols shall be outputfrom the interleaver by rows. For Radio Configuration 1 and 2, theinterleaver rows shall be output in the following order: ٥٢
  • 53. Mobile Evolution to 3G At 9600 or 14400 bps: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 At 4800 or 7200 bps: 1 3 2 4 5 7 6 8 9 11 10 12 13 15 14 16 17 19 18 20 21 23 22 24 25 27 26 28 29 31 30 32 At 2400 or 3600 bps: 1 5 2 6 3 7 4 8 9 13 10 14 11 15 12 16 17 21 18 22 19 23 20 24 25 29 26 30 27 31 28 32 At 1200 or 1800 bps: 1 9 2 10 3 11 4 12 5 13 6 14 7 15 8 16 17 25 18 26 19 27 20 28 21 29 22 30 23 31 24 32 For the Access Channel, the Enhanced Access Channel, the Reverse Common Control Channel, and the Reverse Traffic Channel with Radio Configurations 3, 4, 5, and 6, the symbols input to the interleaver are written sequentially at addresses 0 to the block size (N) minus one. The mobile station may support interleaving over 2 or 4 consecutive frames on the Reverse Supplemental Channel at data rates of 9600 bps or higher as specified by MULTI_FRAME_LENGTHs. The structure of the n-frame block interleaver (n = 2 or 4) is the same as a single frame interleaver. However, the block size of the interleaver is extended to n times the block size for a single interleaver2.8) Orthogonal Modulation and Spreading ٥٣
  • 54. Mobile Evolution to 3GWhen transmitting on the Access Channel or the Reverse Traffic Channelwith Radio Configurations 1 and 2, the mobile station uses orthogonalmodulation. When transmitting on the Enhanced Access Channel, theReverse Common Control Channel, or the Reverse Traffic Channel inRadio Configuration 3 through 6, the mobile station uses orthogonalspreading.2.8.1) Orthogonal ModulationWhen operating in Radio Configuration 1 or 2, modulation for theReverse CDMA Channel shall be 64-ary orthogonal modulation. One of64 possible modulation symbols is transmitted for each six repeated codesymbols. The modulation symbol shall be one of 64 mutually orthogonalwaveforms generated using Walsh functions. The modulation symbolsshall be selected according to the following formula:Modulation symbol index = c0 + 2c1 + 4c2 + 8c3 + 16c4 + 32c5,Where c5 shall represent the last (or most recent) and c0 the first (oroldest) binary valued (‘0’ and ‘1’) repeated code symbol of each group ofsix repeated code symbols that form a modulation symbol index.The period of time required to transmit a single modulation symbol shallbe equal to 1/4800 second (208.333... µs). The period of time associatedwith one sixty-fourth of the modulation symbols is referred to as a Walshchip and shall be equal to 1/307200 second (3.255... µs).Within a modulation symbol, Walsh chips shall be transmitted in theorder of 0, 1, 2... 63 ٥٤
  • 55. Mobile Evolution to 3G2.8.2) Orthogonal SpreadingWhen operating in Radio Configuration 3, 4, 5, or 6, the mobile stationshall use orthogonal spreading. Table 14 specifies the Walsh functionsthat are applied to the Reverse CDMA Channels. Walsh Functions for Reverse CDMA Channels Channel Type Walsh Function Reverse Pilot Channel W032 Enhanced Access Channel W4 8 Reverse Common Control W4 8 Channel Reverse Dedicated Control W816 Channel Reverse Fundamental Channel W416 Reverse Supplemental Channel 1 W12 or W2 4 Reverse Supplemental Channel 2 W2 4 or W6 8 Table 14Since the Walsh function operations occur at the chip rate, this post-interleaver symbol repetition factor is the number of Walsh functionsequence repetitions per interleaver output symbol.When a mobile station only supports one Reverse Supplemental Channel,it should support Reverse Supplemental Channel 1. ReverseSupplemental Channel 1 should use Walsh Function W24 when possible.2.9) Discontinuous Transmission ٥٥
  • 56. Mobile Evolution to 3G2.9.1) Rates and GatingWhen operating with Radio Configuration 1 or 2, the Reverse CodeChannel interleaver output stream is time-gated to allow transmission ofcertain interleaver output symbols and deletion of others. This process isillustrated in Figure 20. As shown in the figure, the duty cycle of thetransmission gate varies with the transmit data rate. When the transmitdata rate is 9600 or 14400 bps, the transmission gate allows all interleaveroutput symbols to be transmitted. When the transmit data rate is 4800 or7200 bps, the transmission gate allows one-half of the interleaver outputsymbols to be transmitted, and so forth. The gating process operates bydividing the 20 ms frame into 16 equal length (i.e., 1.25 ms) periods,called power control groups (PCG). Certain power control groups aregated-on (i.e., transmitted), while other groups are gated-off (i.e., nottransmitted).The assignment of gated-on and gated-off groups, referred to as the databurst randomizing function. The gated-on power control groups arepseudo randomized in their positions within the frame. The data burstrandomizer ensures that every code symbol input to the repetition processis transmitted exactly once.When transmitting on the Access Channel, the code symbols are repeatedonce (each symbol occurs twice) prior to transmission. The data burstrandomizer is not used when the mobile station transmits on the AccessChannel. Therefore, both copies of the repeated code symbols aretransmitted.When transmitting on the Enhanced Access Channel the data rate for theEnhanced Access header shall be fixed at 9600 bps. The data rate for the ٥٦
  • 57. Mobile Evolution to 3Gmessage portion shall not vary over the message when transmitting on theEnhanced Access Channel or the Reverse Common Control Channel.Gating is not used on the Enhanced Access Channel or the ReverseCommon Control Channel.2.9.2) Data Burst Randomizing AlgorithmThe data burst randomizer generates a masking pattern of ‘0’s and ‘1’sthat randomly masks out the redundant data generated by the coderepetition. The masking pattern is determined by the data rate of theframe and by a block of 14 bits taken from the long code. These 14 bitsshall be the last 14 bits of the long code used for spreading in the previousto the last power control group of the previous frame (see Figure 20). Inother words, these are the 14 bits which occur exactly one power controlgroup (1.25 ms) before each Reverse Code Channel frame boundary.These 14 bits are denoted asb0 b1 b2 b3 b4 b5 b6 b7 b8 b9 b10 b11 b12 b13,Where b0 represents the oldest bit and b13 represents the latest bit. Reverse CDMA Channel Variable Data Rate Transmission for Radio Configurations 1 and 2 Example ٥٧
  • 58. Mobile Evolution to 3G 576 code symbols  20 ms = 96 modulation symbols 16 Power Control Groups  36 code symbols  1.25 ms = 6 modulation symbols 1 Power Control Group  Previous Frame 9600 bps and 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 14400 bps frames Power Control Group number Code symbols transmitted: 1 33 65 97 ... 481 513 545 2 34 66 98 ... 482 514 546 Previous Frame 4800 bps and 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 7200 bps frames Code symbols transmitted: 1 17 33 49 ... 241 257 273 2 18 34 50 ... 242 258 274 Previous Frame 2400 bps and 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 3600 bps frames Code symbols transmitted: 1 9 17 25 ... 121 129 137 2 10 18 26 ... 122 130 138 Previous Frame 1200 bps and 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1800 bps frames Code symbols transmitted: 1 5 9 13 ... 61 65 69 2 6 10 14 ... 62 66 70 PN bits used Sample masking streams shown for scrambling are for the 14-bit PN sequence: (b0, b1, ..., b13) = 0 0 1 0 1 1 0 1 1 0 0 1 0 0 b b b b b b b b b b b b b b 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 PCG 14 PCG 15 Fig 202.10) Mobile station Receive diversity:The ordinary rake receiver shown in Fig 21 is modified in Fig 22 to getadvantage of the Orthogonal Transmit Diversity done at the BS. Fig 21 ٥٨
  • 59. Mobile Evolution to 3G Fig 22Additional integrators for the pilot and data channels for OTD.The hot topic today is the use of mobile station receive diversity2 micro strip antennas are embedded in the mobile station forthe purpose of Rx diversity. ٥٩
  • 60. Mobile Evolution to 3G ٦٠
  • 61. Mobile Evolution to 3GUse of diversity reception at the mobile improves thecapacity of forward link.MS Diversity Combining Schemes:• MMSE Combining– Minimum Mean Squared Error Combining– Weights for each path are chosen to give Minimum of the MeanSquare Error (MMSE) between the combined voltage stream andthe signal• MRC Combining– Maximal Ratio Combining– For each path, signals from the antennas are combinedProportional to the SNR of that path– When noise and interference for a path are uncorrelatedbetween the two antennas, MRC is equivalent toMMSE ٦١
  • 62. Mobile Evolution to 3GDiversity Receive Handset• 1900 MHz PCS handset• Modified to include an additional antenna and receiver ٦٢
  • 63. Mobile Evolution to 3G• Primary antenna is the original extendable whip antenna used forboth transmits and receive• Secondary antenna is a Wire Inverted-F Antenna (WIFA) usedonly for second receive chainConclusion Increasing Capacity with ReceiverDiversity:• Only practical with CDMA• Backward compatible with CDMA systems• Does not require a new interoperability standard• Transparent to the operation of the network and users• Can be rolled out at a chosen pace– Geographical distribution– Customer profile ٦٣
  • 64. Mobile Evolution to 3G – Capacity improvement is simply proportional to the usage of diversity handsets Vocoder of CDMA2000The Selectable Mode Vocoder (SMV) is a breakthrough technology thatprovides significant capacity and quality gains on cdmaOne andCDMA2000 systems. A vocoder converts the spoken word into digitalcode and vice versa. The global standards body, 3GPP2, with supportfrom the CDG, recently completed the development of the SMValgorithm and released it for implementation. The state-of-the-arttechnology utilized in SMV will allow CDMA subscribers to enjoysuperior quality while allowing service providers to increase capacity asneeded.Furthermore, SMV offers CDMA carriers the flexibility to tradeoff smallquality losses vs. large system capacity gains. Wireless operators can gainup to 75% increase in system capacity compared to the current CDMAvocoders by using the lower encoding rates of SMV. Wireless operatorscan also provide improvements in voice quality by using data ratessimilar to the current CDMA vocoders. SMV operational mode can becontrolled on a static or dynamic basis, allowing carriers furtherefficiency in service at peak loaded times ٦٤
  • 65. Mobile Evolution to 3G 3) Forward linkThe forward link supports chip rates of N X 1.2288 Mcps (N = 1, 3, 6, 9, 12). ForN = 1, the spreading is similar to IS-95-B, however QPSK modulation and fastclosed loop power control are employed. There are two options for chip ratescorresponding to N > 1: multi-carrier and direct spread.The multi-carrier approach de-multiplexes modulation symbols onto N separate1.25 MHz carriers (N = 3, 6, 9, 12). Each carrier is spread with a 1.2288 Mcpschip rate.The N > 1 direct spread approach transmits modulation symbols on a singlecarrier which is spread with a chip rate of N X 1.2288 Mcps(N = 3, 6, 9, 12). Figure 21 shows both configurations for a system of 3 times theIS-95-B bandwidth. Fig Fig 21 ٦٥
  • 66. Mobile Evolution to 3G 3.1) Forward Link Physical Layer Characteristics3.1.1) Independent Data ChannelsThe cdma2000 system provides two types of forward link physical data channels(Fundamental and Supplemental) that can each be adapted to a particular type ofservice. The use of Fundamental and Supplemental Channels enables the system tobe optimized for multiple simultaneous services. The two physical channels areseparately coded and interleaved and in general have different transmit powerlevels.3.1.2) Orthogonal Modulation:To reduce or eliminate intra-cell interference, each forward link physical channelis modulated by a Walsh code. To increase the number of usable Walsh codes,QPSK modulation is employed prior to spreading. Every two information bits aremapped into a QPSK symbol. As a result, the available number of Walsh codes isincreased by a factor of two relative to BPSK (pre-spreading) symbols.Furthermore, the Walsh code length varies to achieve different information bitrates.The forward link may be interference limited or Walsh code limited depending onthe specific deployment and operating environment. When a Walsh code limitoccurs, additional codes may be created by multiplying Walsh codes by themasking functions. The codes created in this way are called Quasi-OrthogonalFunctions. 3.1.3) Transmit Diversity: ٦٦
  • 67. Mobile Evolution to 3GTransmit diversity can reduce the required Ec/Ior (required transmit power perchannel) and thus enhance capacity. Transmit diversity can be implemented indifferent ways:a) Multi-Carrier Transmit Diversity:Antenna diversity can be implemented in a multi-carrier forward link with noimpact on the subscriber terminal, where a subset of the carriers is transmitted oneach antenna. This provides improved frequency diversity and hence increasesforward link capacity.In addition, antennas can be substantially separated to provide good spatialdiversity. ٦٧
  • 68. Mobile Evolution to 3Gb) Direct-Spread Transmit Diversity:Orthogonal Transmit Diversity (OTD) may be used to provide transmit diversityfor direct spread. The implementation of OTD is as follows. Coded bits are splitinto two data streams and are transmitted via separate antennas. A differentorthogonal code is used per antenna for spreading. This maintains theorthogonality between the two output streams, and hence self-interference iseliminated in flat fading. Note that by splitting the coded data into two separatedata streams, the effective number of spreading codes per user is the same as thecase without OTD because we double the length of the Walsh code used. AnAuxiliary Pilot is introduced for the additional antenna. Note: the data rates areconstant as before the OTD. ٦٨
  • 69. Mobile Evolution to 3GC) The use of smart antennas Beam Switching Overview – Fixed beams technology (from 3 to 4) within existing sectors – Same pilot in one sector illuminates all beams – Compatible with all IS-95A/B, CDMA2000 1X, 1xEV-DV Voice capacity gains estimated to be between 1.8X and 2.3X (Voice) over a 3 sector site ٦٩
  • 70. Mobile Evolution to 3G Beam Steering Overview – Adaptive beam per user – Potential impacts on Asics and requires calibration – More sophisticated method – Voice capacity gains 2X to 3X (Voice) over 3 sector sites • Smart antennas are a cost effective means of increasing voice/data capacity – Increases capacity and/or coverage – Can increase capacity in excess of 2X relative to 3 sectors • Switched/Steered beams yield best performance across technologies given constraints – Number of antennas, cables, amplifiers, visual profile – Standards • Capacity of 1xEV-DV shared channel increased by using switched beams with 2-user CDM Note: Given limitations on resources (antennas, cables, amplifiers), the gains from beamwidth reduction are typically larger than diversity3.1.4) Rate Matching:The cdma2000 system uses several approaches to match the data rates to theWalsh spreader input rates. These include adjusting the code rate, using symbolrepetition with or without symbol puncturing, and sequence repetition.Specifically, sub rates of speech signals are generated by symbol repetition and by ٧٠
  • 71. Mobile Evolution to 3G symbol puncturing when necessary. A Supplemental Channel rate not equal to a given channel data rate is realized by sequence repetition or by symbol repetition with symbol puncturing to match the desired channel data rate. Both of these rate- matching approaches provide flexibility in matching data rates to channel rates. 3.1.5) Frame Length The cdma2000 system supports 5 and 20 ms frames for control information on the Fundamental and Dedicated Control Channels, and uses 20 ms frames for other types of data (including voice). Interleaving and sequence repetition are over the entire frame interval. This provides improved time diversity over systems that use shorter frames. The 20 ms frames are used for voice. 3.1.6) Forward Error Correctiona) Convolutional Codes The cdma2000 forward link uses K=9 convolutional codes for the Fundamental Channel (F-FCH). The Supplemental Channel (F-SCH) uses K=9 convolutional codes for rates up to and including 14.4 kbps. Convolutional codes for higher data rates on the F-SCH are optional and Turbo codes are preferred. The parameters of the convolutional codes used for the forward link are given Turbo Codes: The Forward Supplemental Channel (F-SCH) uses Turbo codes with K=4, R = 1/4, 1/3, and 1/2. Turbo codes for data rates greater than 14.4 kbps are preferred. ٧١
  • 72. Mobile Evolution to 3GTurbo codes have been shown to provide near Shannon capacity limit performanceover Additive White Gaussian Noise (AWGN) channels by means of an iterative,soft-input/soft-output decoding algorithm and, thus, significantly outperformconventional convolutional codes of similar decoding complexity. As the capacityof all CDMA technologies is highly dependent on the operating Eb /No, improvedperformance translates directly to higher capacity. The general Turbo codeencoder is shown in Figure 21 The Turbo encoder employs two systematicrecursive convolutional codes connected in parallel, with an interleaver (the“Turbo interleaver”) preceding the second recursive convolutional encoder. Information bits Parity Bits Constituent encoder #1 Puncture Parity Bits Interleaver Constituent encoder #2 Fig 213.2) Radio configurations for the forward traffic channel:3.3) Channel Structure: ٧٢
  • 73. Mobile Evolution to 3G Forward channel for spreading rates 1 and 3 Pilot Common Sync. Traffic Broadcast Paging Quick channel control Channels channels channels channels paging s channels (RS1) channel Forward Transmit Auxiliary Pilot diversity Pilot Pilot channel channel Channels 0-1 Dedicated 0-1 MS Power 0-7 Supplemental 0-2 Supplemental Control Fundamental Control Sub Code Channels Radio Channels Radio Channel Channel channel configuration 1-2 Configuration 3-9 Fig 22Figure 22 shows the forward CDMA channels transmitted by the base station.Each of these code channels is orthogonally spread by the appropriate Walsh orquasi-orthogonal function and is then spread by a quadrature pair of PN sequencesat a fixed chip rate of 1.2288 Mcps. Multiple Forward CDMA Channels may beused within a base station in a frequency division multiplexed manner.3.4) Forward Common Channels: ٧٣
  • 74. Mobile Evolution to 3GThe forward common channels use a long code mask and spreading that is knownby all mobile stations. The functional capabilities provided by the forwardcommon channels include: soft handoff, coherent detection, paging, andsynchronization and data communications.3.4.1) Pilot Channel (F-PICH):The pilot channel spreads the all 0’s sequence with Walsh code 0. The channel iscontinuously broadcast throughout the cell in order to provide timing and phaseinformation. The pilot is shared between all mobiles in the cell and is used toobtain fast acquisition of new multipath and channel estimation (i.e., phase andmultipath strength).3.4.2) Forward Common Auxiliary Pilot (F-CAPICH):Certain applications such as antenna arrays and antenna transmit diversity requirea separate pilot for channel estimation and phase tracking. Auxiliary Pilots arecode multiplexed with other forward link channels and use orthogonal Walshcodes. Common Auxiliary Pilots are used with antenna beam-forming applicationsto generate spot beams. Spot beams can be used to increase coverage towards aparticular geographical point or to increase capacity towards hot spots. TheCommon Auxiliary Pilot can be shared among multiple mobile stations in thesame spot beam.3.4.3) Forward Sync Channel (F-SYNC):The Sync Channel is used by mobile stations operating within the coverage areaof the base station to acquire initial time synchronization.3.4.4) Forward Paging Channel (F-PCH): ٧٤
  • 75. Mobile Evolution to 3GA cdma2000 system can have multiple Paging Channels per base station. APaging Channel can transmit at a data rate of 9600 bps or 4800 bps. Signal Point Pilot Mapping Channel Channels XI 0 → +1 Gain (All 0’s) 1 → –1 0 XQ Code Modulation Modulation Symbol Symbol Symbol Block Signal Point Sync Convolutional Symbol Symbol Interleaver Mapping Channel Channel Encoder Repetition Repetition XI (128 0 → +1 Gain Bits R = 1/2, K = 9 (2× Factor) (4× Factor) Symbols) 1 → –1 32 Bits/ 2.4 ksps 4.8 ksps 19.2 ksps 26.666... ms Frame (1.2 kbps) 0 XQ Code Modulation Modulation Symbol Symbol Symbol Block Signal Point Paging Convolutional Symbol Interleaver Mapping Channel Channel Encoder XI Repetition (384 0 → +1 Gain Bits R = 1/2, K = 9 Symbols) 1 → –1 Bits/20 ms Rate (kbps) Rate (ksps) Factor Rate (ksps) 96 4.8 9.6 2× 1 9 .2 0 XQ 192 9.6 19.2 1× 1 9 .2 19.2 ksps Long Code Long Mask for Code Decimator Paging Generator 1.2288 Mcps Channel p Figure 23 Figure shows the structure of: Pilot Channels, Sync Channel, and Paging Channels for Spreading Rate 1 ٧٥
  • 76. Mobile Evolution to 3G Signal Point Pilot Mapping Channel Channels XI 0 → +1 Gain (All 0’s) 1 → –1 0 XQ Code Modulation Modulation Symbol Symbol Symbol Block Signal Point Sync Convolutional Symbol Interleaver Mapping Channel Channel Encoder Repetition XI (384 0 → +1 Gain Bits R = 1/3, K = 9 (4× Factor) Symbols) 1 → –1 32 Bits/ 3.6 ksps 14.4 ksps 26.666... ms Frame (1.2 kbps) 0 XQFigure shows the structure of: Forward Pilot Channel, Auxiliary Pilot Channels,and Sync Channel for Spreading Rate 3The modulation parameters for spreading rate 1:3.5) Broadcast Channel:The Broadcast Channel is an encoded, interleaved, spread, and modulated spreadspectrum signal that is used by mobile stations operating within the coverage areaof the base station. The Broadcast Channel shall be spread by a Walsh or quasi-orthogonal function. ٧٦
  • 77. Mobile Evolution to 3G Broadcast Channel Bits Add 16-Bit Add 8-Bit Convolutional Block (744 Information Bits Frame Encoder Encoder Interleaver per 40, 80, or 160 ms Quality Tail R = 1/2, K = 9 (1,536 Symbols) Broadcast Channel Slot) Indicator Modulation Sequence Signal Point Symbol Repetition Mapping Channel X (1, 2, or 4 38.4 ksps 0 → +1 Gain Times) 1 → –1 Long Code Mask for Long Code Decimator Broadcast Generator Channel Broadcast Channel Structure for Spreading Rate 1 Fig 25 Modulation Parameters for Spreading Rate 1 Data Rate (bps) Parameter 19200 9600 4800 Units PN Chip Rate 1.2288 1.2288 1.228 Mcps 8 Code Rate 1/2 1/2 ½ bits/code symbol Code Sequence 1 2 4 modulation Repetition symbols/ code symbol* Modulation Symbol 38,400 38,400 38,40 sps Rate 0 Walsh Length 64 64 64 PN chips/modulation symbol Processing Gain 64 128 256 PN chips/bit Table 17 ٧٧
  • 78. Mobile Evolution to 3G Broadcast Channel Bits Add 16-Bit Add 8-Bit Convolutional Block (744 Information Bits Frame Encoder Encoder Interleaver per 40, 80, or 160 ms Quality Tail R = 1/3, K = 9 (2,304 Symbols) Broadcast Channel Slot) Indicator Modulation Sequence Signal Point Symbol Repetition Mapping Channel X (1, 2, or 4 57.6 ksps 0 → +1 Gain Times) 1 → –1 Long Code Mask for Long Code Decimator Broadcast Generator Channel Broadcast Channel Structure for Spreading Rate 3 Fig 26Broadcast Channel Modulation Parameters for Spreading Rate 39.3.6) Quick Paging Channel:The Quick Paging Channel is an un-coded, spread and on-off Keying modulatedspread spectrum signal that is used by mobile stations operating within thecoverage area of the base station. The base station uses the Quick Paging Channelto inform mobile stations operating in the Slotted mode while in the idle statewhether or not they should the forward Common Control Channel or the PagingChannel starting in the next Forward Common Control Channel or PagingChannel frame. Symbol Modulation Quick Paging Channel Symbol Signal Point Mapping Repetition Channel Indicators +1 When Indicator Enabled X (2× or 4× Gain (9.6 or 4.8 ksps) 0 Otherwise Factor) Fig 27Quick Paging Channel Structure for Spreading Rate 1 ٧٨
  • 79. Mobile Evolution to 3G Symbol ModulationQuick Paging Channel Symbol Signal Point Mapping Repetition Channel Indicators +1 When Indicator Enabled X (3× or 6× Gain (9.6 or 4.8 ksps) 0 Otherwise Factor) Fig 28 Quick Paging Channel Structure for Spreading Rate 33.7) Forward Common Control Channel:The Forward Common Control Channel is an encoded, interleaved, spread, andmodulated spread spectrum signal that is used by the mobile stations operatingwithin the coverage area of the base station. The base Station uses the ForwardCommon Control Channel to transmit system overhead information and mobilestation overhead messages. Forward Modulation Common Add 8-Bit Convolutional Symbols Block Control Encoder Encoder Interleaver Channel Tail R = 1/4, K = 9 Bits Bits/Frame Rate (kbps) Symbols Rate (ksps) 184 (5 ms) 38.4 768 153.6 184 (10 ms) 19.2 768 76.8 376 (10 ms) 38.4 1,536 153.6 184 (20 ms) 9.6 768 38.4 376 (20 ms) 19.2 1,536 76.8 760 (20 ms) 38.4 3,072 153.6 Signal Point Mapping Channel X 0 → +1 Gain 1 → –1 Long Code Mask for Long Code DecimatorForward Common Generator Control Channel Fig 29 Forward Common Control Channel Structure for Spreading Rate 1 with R = 1/4 Mode Forward Common Control Channel Modulation Parameters ٧٩
  • 80. Mobile Evolution to 3G For Spreading Rate 1 with R = 1/4 Data Rate (bps) Parameter 38,400 19,200 9600 Units PN Chip Rate 1.2288 1.2288 1.2288 Mcps Code Rate 1/4 1/4 ¼ bits/code symbol Code Symbol 1 1 1 modulation Repetition symbols/code symbol* Modulation 153,600 76,800 38,400 sps Symbol Rate Walsh Length 16 32 64 PN chips/modulation symbol Processing Gain 32 64 128 PN chips/bit Table 21 . Forward Common Control Channel Structure for Spreading Rate 3 Forward Modulation Common Add 8-Bit Convolutional Symbols Block Control Encoder Encoder Interleaver Channel Tail R = 1/3, K = 9 Bits Bits/Frame Rate (kbps) Symbols Rate (ksps) 184 (5 ms) 38.4 576 115.2 184 (10 ms) 19.2 576 57.6 376 (10 ms) 38.4 1,152 115.2 184 (20 ms) 9.6 576 28.8 376 (20 ms) 19.2 1,152 57.6 760 (20 ms) 38.4 2,304 115.2 Signal Point Mapping Channel X 0 → +1 Gain 1 → –1 Long Code Mask for Long Code Decimator Forward Common Generator Control Channel Fig 30 Table 22 ٨٠
  • 81. Mobile Evolution to 3G3.8) Forward Dedicated Channels:3.8.1) Forward Dedicated Control Channel:The Forward Dedicated Control Channel is used for the transmission of user andsignaling information to a specific mobile station during a call. Each ForwardTraffic Channel may contain one Forward Dedicated Control Channel. The F-DCCH shall be convolutionally encoded. Modulation Forward Symbols Add Dedicated Add 8 Convolutional Frame Block Control Encoder Encoder W Quality Interleaver Channel Tail Bits R = 1/4, K = 9 Indicator Bits Bits/Frame Bits Rate (kbps) Symbols Rate (ksps) 24 (5 ms) 16 9.6 192 38.4 172 (20 ms) 12 9.6 768 38.4 Fig 31 Forward Dedicated Control Channel Modulation Parameters for RadioForward Dedicated Control Channel Structure for Radio Configuration 6 Modulation Forward Symbols Add Dedicated Add 8 Convolutional Frame Block Control Encoder Encoder W Quality Interleaver Channel Tail Bits R = 1/6, K = 9 Indicator Bits Bits/Frame Bits Rate (kbps) Symbols Rate (ksps) 24 (5 ms) 16 9.6 288 57.6 172 (20 ms) 12 9.6 1,152 57.6 Forward Dedicated Control Channel Modulation Parameters for Radio Configuration 6 ٨١
  • 82. Mobile Evolution to 3GForward Dedicated Control Channel Structure for Radio Configuration 7 Modulation Forward Symbols Add Dedicated Add 8 Convolutional Frame Block Control Encoder Encoder W Quality Interleaver Channel Tail Bits R = 1/3, K = 9 Indicator Bits Bits/Frame Bits Rate (kbps) Symbols Rate (ksps) 24 (5 ms) 16 9.6 144 28.8 172 (20 ms) 12 9.6 576 28.8Forward Dedicated Control Channel Structure for Radio Configuration 7 Modulation Forward Symbols Add Dedicated Add 8 Convolutional Frame Block Control Encoder Encoder W Quality Interleaver Channel Tail Bits R = 1/3, K = 9 Indicator Bits Bits/Frame Bits Rate (kbps) Symbols Rate (ksps) 24 (5 ms) 16 9.6 144 28.8 172 (20 ms) 12 9.6 576 28.8 Fig 34 Forward Dedicated Control Channel Modulation Parameters for Radio Configuration 7 Data Rate (bps) Parameter 9600 Units PN Chip Rate 3.6864 Mcps Code Rate 1/3 bits/code symbol Code Symbol Repetition 1 Modulation symbols/code symbol Modulation Symbol 28,800 Sps Rate Walsh Length 256 PN chips/modulation symbol Processing Gain 384 PN chips/bit Table 24 Forward Dedicated Control Channel Structure for Radio Configuration 8 ٨٢
  • 83. Mobile Evolution to 3G Modulation Forward Symbols Add Dedicated Add Add 8 Frame Convolutional Symbol Block Control Reserved Encoder W Quality Encoder Repetition Interleaver Channel Bits Tail Bits Indicator Bits Bits/Frame Bits Bits Rate (kbps) R Factor Symbols Rate (ksps) 24 (5 ms) 0 16 9.6 1/3 2× 288 57.6 267 (20 ms) 1 12 14.4 1/4 1× 1,152 57.6 Fig 353.9) Forward Traffic Channel:They are used to transmit voice and data applications at a variable rate. The TrafficChannel can be classified into two classes which they are the ForwardFundamental Channel and the Forward Supplemental Channel.3.10) Forward Fundamental Channel:This channel is transmitted at variable rate as in IS-95-B and consequentlyrequires rate detection at the receiver. Each F-FCH is transmitted on a differentorthogonal code channel and supports frame sizes corresponding to 20 ms and 5ms. we can find that convolutional encoder is employed with different code rates.The choice of the code rate can be made depending on the radio environment. The1/2 code rate will allow two times the number of Walsh codes as the rate 1/4 codeat the cost of FEC (Forward Error Correction) performance.Forward Supplemental Channel:The Supplemental Channel (F-SCH) can be operated in two distinct modes. Thefirst mode is used for data rates not exceeding 14.4 kbps and uses blind ratedetection (no scheduling or rate information provided). In The second mode the ٨٣
  • 84. Mobile Evolution to 3Grate information is explicitly provided to the base station (no blind rate detection isperformed).In the first mode, the variable rates provided are those derived from the IS-95-BRate Set 1 (RS1) and Rate Set 2 (RS2). The structures for the variable rate modesare identical to the 20 ms F-FCH. In the second mode, the high data rate modescan have K = 9 convolutional coding or turbo coding with K = 4 componentencoders. For the case of convolutional codes, there are 8 tail bits. For the case ofTurbo codes, there are 6 tail bits and 2 reserve bits.There may be more than one F-SCHs in use at a given time. The individual F-SCHtarget FERs may be set independently with respect to the F-FCH and other F-SCHs, since the optimal FER set point for data is in general different than forvoice. For classes of data services that have less stringent delay requirements, theFER may also be managed by retransmissions. Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 3 Channel Modulation Bits Add Add 8 Symbols Convolutional Frame Reserved/ Symbol Symbol Block or Turbo W Quality Encoder Repetition Puncture Interleaver Encoder Indicator Tail Bits Bits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/4 1× None 192 38.4 16 6 1.5 1/4 8× 1 of 5 768 38.4 40 6 2.7 1/4 4× 1 of 9 768 38.4 80 8 4.8 1/4 2× None 768 38.4 172 12 9.6 1/4 1× None 768N 38.4 360 16 19.2 1/4 1× None 1,536N 76.8 744 16 38.4 1/4 1× None 3,072N 153.6 1,512 16 76.8 1/4 1× None 6,144N 307.2 3,048 16 153.6 1/4 1× None 12,288N 614.4 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 9.6 kbps or less are used for Forward Fundamental Channels. 2. Turbo coding may be used for the Forward Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 36 ٨٤
  • 85. Mobile Evolution to 3GForward Fundamental Channel and Forward Supplemental Channel Modulation Parameters for Radio Configuration 3Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 4Channel Modulation Bits Add Add 8 Symbols Convolutional Frame Reserved/ Symbol Symbol Block or Turbo W Quality Encoder Repetition Puncture Interleaver Encoder Indicator Tail BitsBits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/2 1× None 96 19.2 16 6 1.5 1/2 8× 1 of 5 384 19.2 40 6 2.7 1/2 4× 1 of 9 384 19.2 80 8 4.8 1/2 2× None 384 19.2 172 12 9.6 1/2 1× None 384N 19.2 360 16 19.2 1/2 1× None 768N 38.4 744 16 38.4 1/2 1× None 1,536N 76.8 1,512 16 76.8 1/2 1× None 3,072N 153.6 3,048 16 153.6 1/2 1× None 6,144N 307.2 6,120 16 307.2 1/2 1× None 12,288N 614.4 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 9.6 kbps or less are used for Forward Fundamental Channels. 2. Turbo coding may be used for the Forward Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 37 ٨٥
  • 86. Mobile Evolution to 3GForward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 5Channel Modulation Bits Add Symbols Add 8 Frame Convolutional Symbol Symbol Block Encoder W Quality Encoder Repetition Puncture Interleaver Tail Bits IndicatorBits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/6 1× None 288 57.6 16 6 1.5 1/6 8× 1 of 5 1,152 57.6 40 6 2.7 1/6 4× 1 of 9 1,152 57.6 80 8 4.8 1/6 2× None 1,152 57.6 172 12 9.6 1/6 1× None 1,152N 57.6 360 16 19.2 1/6 1× None 2,304N 115.2 744 16 38.4 1/6 1× None 4,608N 230.4 1,512 16 76.8 1/6 1× None 9,216N 460.8 3,048 16 153.6 1/6 1× None 18,432N 921.6 6,120 16 307.2 1/6 1× None 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 9.6 kbps or less are used for Forward Fundamental Channels. 2. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 38Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 6 Channel Modulation Bits Add Symbols Add 8 Frame Convolutional Symbol Symbol Block Encoder W Quality Encoder Repetition Puncture Interleaver Tail Bits Indicator Bits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/6 1× None 288 57.6 16 6 1.5 1/6 8× 1 of 5 1,152 57.6 40 6 2.7 1/6 4× 1 of 9 1,152 57.6 80 8 4.8 1/6 2× None 1,152 57.6 172 12 9.6 1/6 1× None 1,152N 57.6 360 16 19.2 1/6 1× None 2,304N 115.2 744 16 38.4 1/6 1× None 4,608N 230.4 1,512 16 76.8 1/6 1× None 9,216N 460.8 3,048 16 153.6 1/6 1× None 18,432N 921.6 6,120 16 307.2 1/6 1× None 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 9.6 kbps or less are used for Forward Fundamental Channels. 2. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 39 ٨٦
  • 87. Mobile Evolution to 3GForward Fundamental Channel and Forward Supplemental Channel Modulation Parameters for 20 ms Frames for Radio Configuration 6 ٨٧
  • 88. Mobile Evolution to 3G Data Rate (bps) Parameter 9600×N 4800 2700 1500 Units PN Chip Rate 3.6864 3.686 3.686 3.686 Mcps 4 4 4 Code Rate 1/6 1/6 1/6 1/6 bits/code symbol Code Symbol 1 2 4 8 repeated symbols/ Repetition code symbol Puncturing 1 1 8/9 4/5 modulation Rate symbols/ repeated symbol Modulation 57,600× 57,60 57,60 57,60 sps Symbol Rate N 0 0 0 Walsh Length 128/N 128 128 128 PN chips/ modulation symbol Processing 384/N 768 1365. 2457. PN chips/bit Gain 3 6 Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 7 Channel Modulation Bits Add Add 8 Symbols Convolutional Frame Reserved/ Symbol Symbol Block or Turbo W Quality Encoder Repetition Puncture Interleaver Encoder Indicator Tail Bits Bits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 16 9.6 1/3 1× None 144 28.8 16 6 1.5 1/3 8× 1 of 5 576 28.8 40 6 2.7 1/3 4× 1 of 9 576 28.8 80 8 4.8 1/3 2× None 576 28.8 172 12 9.6 1/3 1× None 576N 28.8 360 16 19.2 1/3 1× None 1,152N 57.6 744 16 38.4 1/3 1× None 2,304N 115.2 1,512 16 76.8 1/3 1× None 4,608N 230.4 3,048 16 153.6 1/3 1× None 9,216N 460.8 6,120 16 307.2 1/3 1× None 18,432N 921.6 12,264 16 614.4 1/3 1× None 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 9.6 kbps or less are used for Forward Fundamental Channels. 2. Turbo coding may be used for the Forward Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 40 Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 8 ٨٨
  • 89. Mobile Evolution to 3G Channel Modulation Bits Add Add 8 Symbols Add Convolutional Frame Reserved/ Symbol Block Reserved or Turbo W Quality Encoder Repetition Interleaver Bits Encoder Indicator Tail Bits Bits/Frame Bits Bits Rate (kbps) R Factor Symbols Rate (ksps) 24 (5 ms) 0 16 9.6 1/3 2× 288 57.6 21 1 6 1.8 1/4 8× 1,152 57.6 55 1 8 3.6 1/4 4× 1,152 57.6 125 1 10 7.2 1/4 2× 1,152 57.6 267 1 12 14.4 1/4 1× 1,152N 57.6 552 0 16 28.8 1/4 1× 2,304N 115.2 1,128 0 16 57.6 1/4 1× 4,608N 230.4 2,280 0 16 115.2 1/4 1× 9,216N 460.8 4,584 0 16 230.4 1/4 1× 18,432N 921.6 9,192 0 16 460.8 1/4 1× 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 14.4 kbps or less are used for Forward Fundamental Channels. 2. Turbo coding may be used for the Forward Supplemental Channels with rates of 28.8 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 41Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration Channel Modulation Bits Add Add 8 Symbols Add Convolutional Frame Reserved/ Symbol Symbol Block Reserved or Turbo W Quality Encoder Repetition Puncture Interleaver Bits Encoder Indicator Tail Bits Bits/Frame Bits Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps) 24 (5 ms) 0 16 9.6 1/3 1× None 144 28.8 21 1 6 1.8 1/2 8× None 576 28.8 55 1 8 3.6 1/2 4× None 576 28.8 125 1 10 7.2 1/2 2× None 576 28.8 267 1 12 14.4 1/2 1× None 576N 28.8 552 0 16 28.8 1/2 1× None 1,152N 57.6 1,128 0 16 57.6 1/2 1× None 2,304N 115.2 2,280 0 16 115.2 1/2 1× None 4,608N 230.4 4,584 0 16 230.4 1/2 1× None 9,216N 460.8 9,192 0 16 460.8 1/2 1× None 18,432N 921.6 20,712 0 16 1,036.8 1/2 1× 2 of 18 36,864N 1,843.2 Notes: 1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 14.4 kbps or less are used for Forward Fundamental Channels. 2. Turbo coding may be used for the Forward Supplemental Channels with rates of 28.8 kbps or more; otherwise, K = 9 convolutional coding is used. 3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail. 4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4). Fig 423.11) Power Control Subchannel:A power control sub-channel is transmitted only on the Forward Fundamental ٨٩
  • 90. Mobile Evolution to 3GChannel or the Forward Dedicated Control Channel. When the mobile station isoperating in the transmission mode, the sub-channel shall transmit at a rate of onebit (0 or 1) every 1.25 ms (800 bps). The 20 ms frame is divided into 16 powercontrol groups (PCG). The long code mask is used to determine the location of thepower control bit in each PCG. Long Code Generation, Power Control, and Signal Point Mapping for Forward Traffic Channels Signal Point Mapping Channel W 0 → +1 Gain 1 → –1 Power Control X Power Control Symbol Bits Puncture Power ± 1 Values Control 16 Bits per Subchannel 20 ms Frame Gain or 4 Bits per 5 ms Frame Puncture Timing Control (800 Hz) Power Long Code Long Control Mask Code Decimator Bit Position for User m Generator Extractor Power control symbol puncturing is on the Forward Fundamental Channels and Forward Dedicated Control Channels only. The decimator output rate matches the modulation symbol rate. Fig 433.12) Symbol De-multiplexing:Symbol de-multiplexing is performed on every code channel in the forwardCDMA channels. The Forward Pilot channel, the Transmit Diversity Pilotchannel, the Auxiliary Pilot channel, Paging channel and the Forward Trafficchannel with Radio configurations 1 and 2 shall be de-multiplexed using the non-OTD de-multiplexer only (the OTD and MC de-multiplexers are not allowed). TheBroadcast channels, the Quick Paging, the Forward Common Control channels, ٩٠
  • 91. Mobile Evolution to 3Gand Forward Traffic channels with Radio configuration 3 through 9 shall be de-multiplexed using the non-OTD, OTD, or MC mode. Demultiplexer Structure for Spreading Rate 1 YI XI YI X DEMUX YQ XQ YQ a) Non-OTD Mode YI1 YI1 XI DEMUX YI2 YI2 X DEMUX YQ1 YQ1 XQ DEMUX YQ2 YQ2 b) OTD Mode The DEMUX functions distribute input symbols sequentially from the top to the bottom output paths. Fig 44 De-multiplexer Structure for Spreading Rate 3 ٩١
  • 92. Mobile Evolution to 3G YI XI YI X DEMUX YQ XQ YQ a) DS Non-OTD Mode YI1 YI1 XI DEMUX YI2 YI2 X DEMUX YQ1 YQ1 XQ DEMUX YQ2 YQ2 b) DS OTD Mode YI1 YI1 XI DEMUX YI2 YI2 YI3 YI3 X DEMUX YQ1 YQ1 YQ2 XQ DEMUX YQ2 YQ3 YQ3 c) MC ModeThe DEMUX functions distribute input symbols sequentially from the top to the bottom output paths. Fig 45 3.13) Orthogonal Modulation To reduce or eliminate intra-cell interference, each forward link physical channel is modulated by a Walsh code. To increase the number of usable Walsh codes, QPSK modulation is employed prior to spreading. Every two information bits are mapped into a QPSK symbol. As a result, ٩٢
  • 93. Mobile Evolution to 3Gthe available number of Walsh codes is increased by a factor of tworelative to BPSK (pre-spreading) symbols. Furthermore, the Walsh code length varies to achieve differentinformation bit rates. The forward link may be interference limited orWalsh code limited depending on the specific deployment and operatingenvironment. When a Walsh code limit occurs, additional codes may becreated by multiplying Walsh codes by the masking functions, the codescreated in this way are called Quasi-Orthogonal Functions.3.13.1) Orthogonal and Quasi-Orthogonal spreading Walsh functions shall be used with Radio configuration 1 and 2. Walshfunctions or quasi-orthogonal functions shall be used with Radioconfiguration 3 through 9. Each code channel transmitted on the forward CDMA channel shall bespread with Walsh function or quasi-orthogonal function at a fixed chiprate of 1.2288 Mcps for spreading rate 1 and 3.6864 Mcps for spreadingrate 3 to provide channelization among all code channels on a givenforward CDMA channel.One of N-ary (N≤Nmax) time-orthogonal Walsh functions shall be used.A code channel that is spread using walsh function n from N-aryorthogonal set (0≤n≤N-1) shall be assigned to code channel number n oflength N. The Walsh function spreading sequence shall repeat with aperiod of (N/1.2288) µs for spreading rate 1 and (N/3.6864) µs for ٩٣
  • 94. Mobile Evolution to 3Gspreading rate 3 which is equal; to the duration of one forward trafficchannel modulation symbol. Quasi-orthogonal functions (QOF`S) shall be created using a none zerosign multiplier QOF`S mask and a none zero rotate enable Walsh functionas specified in the next two tables. The repeated sequence of anappropriate Walsh function shall be multiplied by the repeated sequenceof masks with symbols +1 and –1 which correspond to the sign multiplierQOF mask values of 0 and 1, respectively. The sequence shall also bemultiplied by the repeated sequence of 1’s and j’s (j is the complexnumber representing a 90˚ phase shift) which correspond to the rotateenable Walsh function values of 0 or 1, respectively. The sign multiplierQOF masks (QOFsign) and the rotate enable Walsh function (Walshrot)given in the next two tables.Function Masking function Binary representation of QOFsign (hex) Walshrot0 0000000000000000000000000000000 W0256 0000000000000000000000000000000 ٩٤
  • 95. Mobile Evolution to 3G1 7d72141bd7d8beb1727de4eb2728b1be W10256 8d7de414d828b1417d8deb1bd72741b12 7d27e4be82d8e4bed87dbe1bd87d41e4 W213256 4eebd7724eeb288d144e7228ebb172283 7822dd8777d2d2774beeee4bbbe11e44 W111256 1e44bbe111b4b411d27777d2227887ddFunction Masking function Binary representation of QOFsign (hex) Walshrot0 0000000000000000000000000000000 W0512 0000000000000000000000000000000 0000000000000000000000000000000 00000000000000000000000000000001 4bdd442d22b42d44771e78ee1e771187 W214512 b422442ddd4b2d4488e178eee1881187 d244ddb444d24b2211781e8887ee881e d244224b44d2b4dd1178e17787ee77e12 28e4be724172281b28e4be724172281b W117512 1bd78d418dbee4d7e42872be72411b28 824eeb27142782b1824eeb27142782b1 b17dd814d8eb4e7d4e8227eb2714b1823 2be7428e172481b2d4e7427117db7eb2 W375512 7142e7d44d8124e871bd18d4b2812417 18d471bd2417b281e7d4714224e84d81 4271d4e77eb217db428e2be781b21724Code channel number zero shall always be assigned to the forward pilotchannel if the sync. Channel is present; it shall be assigned code W3264 ٩٥
  • 96. Mobile Evolution to 3Gwhen operating in spreading rate 1. If paging channels are present, theyshall be assigned to code channel numbers W164 to W764, consecutively. Other code channels of varying Walsh lengths are usable for auxiliarypilot channels, common control channels, and forward traffic channels,provided that they are chosen to be orthogonal or quasi-orthogonal to allother code channels in use. When operating in OTD mode, the base station shall use two double-length Walsh functions or quasi-orthogonal functions in lieu of the singleWalsh function for the forward traffic channels.3.14) Transmit Diversity Transmit diversity can reduce the required Ec/Ior (required transmitpower per channel) and thus enhance capacity. Transmit diversity can beimplemented in different ways: 1-Multi-Carrier Transmit Diversity Antenna diversity can be implemented in a multi-carrier forward linkwith no impact on the subscriber terminal, where a subset of the carriersis transmitted on each antenna. This provides improved frequencydiversity and hence increases forward link capacity. In addition, antennascan be substantially separated to provide good spatial diversity.2 -Direct-Spread Transmit Diversity ٩٦
  • 97. Mobile Evolution to 3G Orthogonal Transmit Diversity (OTD) may be used to provide transmitdiversity for direct spread. The implementation of OTD is as follows.Coded bits are split into two data streams and are transmitted via separateantennas. A different orthogonal code is used per antenna for spreading.This maintains the orthogonality between the two output streams, andhence self-interference is eliminated in flat fading. Note that by splittingthe coded data into two separate data streams, the effective number ofspreading codes per user is the same as the case without OTD. AnAuxiliary Pilot is introduced for the additional antenna.Block interleaving For the Sync channel, Paging channels, and the Forward Trafficchannels, all the symbols after symbol repetition and subsequentpuncturing, if used, shall be block interleaved.The interleaver parameters m and J are specified in next table.Multi-frame Interleaving The base station may support interleaving over 2 or 4 consecutiveframes on the forward Supplemental channel at data rates of 9600 bps orhigher as specified by MULTI- FRAME- LENGTH. The structure of the n-frame block interleaver (n=2 or 4)is the same asa single frame interleaver.however,the block size of the interleaver is n ٩٧
  • 98. Mobile Evolution to 3Gtimes the block size for a single frame. The interleaver parameters for then-frame block interleaver are the same as the previous table.4) Cdma2000 handoff 4.1) Handoff ProceduresMobile Assisted Soft-Handoff Procedures The mobile station monitors the Forward Pilot Channel level receivedfrom neighboring base stations and reports to the network those F-PICHswhich cross a given set of thresholds. Those thresholds can bedynamically adjusted. Two types of thresholds are used: the first one to report F-PICHs withsufficient power to be used for coherent demodulation, and the secondone to report F-PICHs whose power has declined to a level where it is notbeneficial to be used for coherent demodulation. Based on this information, the network orders the mobile station to addor remove F-PICHs from its Active Set .The same user informationmodulated by the appropriate base station code is sent from multiple basestations. Coherent combining of the different signals from differentsectorized antennas, from different base stations, or from the sameantenna but on different multiple path components is performed in themobile station by the usage of Rake receivers. A mobile station willtypically place at least one Rake receiver finger on the signal from eachbase station in the Active Set. However, this is not required. If the signalfrom the base station is temporarily weak, then the mobile station canassign the finger to a stronger base station. The signal transmitted by a ٩٨
  • 99. Mobile Evolution to 3Gmobile station is processed by base stations with which the mobile stationis in soft handoff. The received signal from different sectors of a basestation (cell) can be combined in the base station (on a symbol by symbolbasis), and the received signal from different base stations (cells) can beselected in the infrastructure (on a frame by frame basis). Soft handoff results in increased coverage range, capacity on thereverse link (soft handoffs require less mobile transmit power)., fewerdropped calls and improved clarity.4.2) Dynamic Soft-Handoff Thresholds While soft handoff improves overall performance, it has been observedin the field that it may in some situations negatively impact systemcapacity and network resources. On the forward link, excessive handoffreduces system capacity (more power amplifier resources required) whileon the reverse link, it costs more network resources (backhaulconnections). Adjusting the handoff thresholds at the base station will not necessarilysolve the problem. Some locations in the cell receive only weak F-PICHs(requiring a lower threshold) and other locations receive a few strong anddominant F-PICHs (requiring higher handoff thresholds). The principle of dynamic threshold for adding F-PICHs (i.e., addingsoft handoff branches to the mobile station) is as follows:The mobile station detects F-PICHs crossing a given static threshold T1.The metric for the F-PICH (signal from a given base station) in this case ٩٩
  • 100. Mobile Evolution to 3Gis the ratio of F-PICH energy per chip to total received power (notedEc/Io).When crossing this threshold the F-PICH is moved to a candidate set. It isthen searched more frequently and tested against a second dynamicthreshold T2. Comparison with this second threshold T2 will determine ifthe F-PICH is worth adding to the Active Set (starting to be used forcoherent demodulation). Threshold T2 is a function of the total energy ofthe F- PICHs demodulated coherently (in the Active Set).When F-PICHs in the Active Set are weak, adding an additional F-PICH(even weak) will improve performance. When there is one or moredominant F-PICHs, adding an additional weaker F-PICH above T1 willnot improve performance but will utilize more network resources. Themethod described above reduces and optimizes the network resourcesutilization. Figure 1 graphically shows the difference between a static anddynamic threshold.Where SOFT_SLOPE and ADD_INTERCEPT are system parameters tobe adjusted.When F-PICHs in the Active Set are weak, adding an additional F-PICH(even weak) will improve performance. When there is one or moredominant F-PICHs, adding an additional weaker F-PICH above T1 willnot improve performance but will utilize more network resources. Themethod described above reduces and optimizes the network resourcesutilization. Figure 1 graphically shows the difference between a static anddynamic threshold. ١٠٠
  • 101. Mobile Evolution to 3GStatic and dynamic thresholdsTime graph of soft handoffs during dynamic range. After detecting an F-PICH above T2, the mobile station will report itback to the network. The network will then set up the handoff resourcesand order the mobile station to coherently demodulate this additional F-PICH. F-PICHs can be dropped from the Active Set (removing a softhandoff connection) according to the same principles. ١٠١
  • 102. Mobile Evolution to 3G When the F-PICH strength decreases below a dynamic threshold T3,the handoff connection is removed. The F-PICH is moved back to thecandidate set. The threshold T3 is a function of the total energy of F-PICHs in the Active Set (similar to T2). F-PICHs not contributingsufficiently to the total F-PICH energy will be dropped. When furtherdecreasing below a static threshold T4 a F-PICH is removed from theCandidate set. An F-PICH dropping below a threshold (e.g., T3 and T4)is reported back to the network only after being below the threshold for aspecific period. This timer allows for a fluctuating F-PICH not to beprematurely reported. Figure 2 shows a time representation of soft handoff and associatedevent when the mobile station moves away from a serving base station(F-PICH 1) towards a new base station (F-PICH 2). Combining static anddynamic thresholds (versus static thresholds only) results in reduced softhandoff regions.The major benefit of this technique is to limit soft handoff to areas andtimes when it is most beneficial.Advantages of CDMA2000CDMA2000 benefited from the extensive experience acquired throughseveral years of operation of cdmaOne systems. As a result, CDMA2000is a very efficient and robust technology. Supporting voice and data, thestandard was devised and tested in various spectrum bands, including thenew IMT-2000 allocations.There is tremendous demand for new services and operators are lookingto provide these to many more subscribers at reasonable prices.The unique features, benefits, and performance of CDMA2000 make it anexcellent technology for high-voice capacity and high-speed packet data.The fact that CDMA2000 1X has the ability to support both voice anddata services on the same carrier makes it cost effective for wirelessoperators. ١٠٢
  • 103. Mobile Evolution to 3GDue to its optimized radio technology, CDMA2000 enables operators toinvest in fewer cell sites and deploy them faster, ultimately allowing theservice providers to increase their revenues with faster Return onInvestment (ROI). Increased revenues, along with a wider array ofservices, make CDMA2000 the technology of choice for serviceproviders.Increased Voice CapacityVoice is the major source of traffic and revenue for wireless operators,but packet data will emerge in coming years as important source ofincremental revenue. CDMA2000 delivers the highest voice capacity andpacket data throughput using the least amount of spectrum for the lowestcost.CDMA2000 1X supports 35 traffic channels per sector per RF (26Erlang/sector/RF) using the EVRC vocoder, which became commercial in1999.Voice capacity improvement in the forward link is attributed to fasterpower control, lower code rates (1/4 rate), and transmit diversity (forsingle path Rayleigh fading). In the reverse link, capacity improvement isprimarily due to coherent reverse link.Higher Data ThroughputTodays commercial CDMA2000 1X networks (phase 1) support a peakdata rate of 153.6 kbps. CDMA2000 1xEV-DO, commercial in Korea,enables peak rates of up to 2.4 Mbps and CDMA2000 1xEV-DV will becapable of delivering data of 3.09 Mbps.Frequency Band FlexibilityCDMA2000 can be deployed in all cellular and PCS spectrum.CDMA2000 networks have already been deployed in the 450 MHz, 800MHz, 1700 MHz, and 1900 MHz bands; deployments in 2100 MHz andother bands are expected in 2004. CDMA2000 can also be implementedin other frequencies such as 900 MHz and 1800 MHz and 2100 MHz.The high spectral efficiency of CDMA2000 permits high trafficdeployments in any 1.25 MHz channel of spectrum.Increased Battery LifeCDMA2000 significantly enhances battery performance. Benefitsinclude: • Quick paging channel operation • Improved reverse link performance ١٠٣
  • 104. Mobile Evolution to 3G • New common channel structure and operation • Reverse link gated transmission • New MAC states for efficient and ubiquitous idle time operationSynchronizationCDMA2000 is synchronized with the Universal Coordinated Time(UCT). The forward link transmission timing of all CDMA2000 basestations worldwide is synchronized within a few microseconds. Basestation synchronization can be achieved through several techniquesincluding self-synchronization, radio beep, or through satellite-basedsystems such as GPS, Galileo, or GLONASS. Reverse link timing isbased on the received timing derived from the first multipath componentused by the terminal.There are several benefits to having all base stations in a networksynchronized: • The common time reference improves acquisition of channels and hand-off procedures since there is no time ambiguity when looking for and adding a new cell in the active set. • It also enables the system to operate some of the common channels in soft hand-off, which improves the efficiency of the common channel operation. • Common network time reference allows implementation of very efficient "position location" techniques.Power ControlThe basic frame length is 20 ms divided into 16 equal power controlgroups. In addition, CDMA2000 defines a 5 ms frame structure,essentially to support signaling bursts, as well as 40 and 80 ms frames,which offer additional interleaving depth and diversity gains for dataservices. Unlike IS-95 where Fast Closed Loop Power Control wasapplied only to the reverse link, CDMA2000 channels can be powercontrolled at up to 800 Hz in both the reverse and forward links. Thereverse link power control command bits are punctured into the F-FCH orthe F-DCCH (explained in later sections) depending on the serviceconfiguration. The forward link power control command bits arepunctured in the last quarter of the R-PICH power control slot.In the reverse link, during gated transmission, the power control rate isreduced to 400 or 200 Hz on both links. The reverse link power controlsub-channel may also be divided into two independent power controlstreams, either both at 400 bps, or one at 200 bps and the other at 600 bps.This allows for independent power control of forward link channels. ١٠٤
  • 105. Mobile Evolution to 3GIn addition to the closed loop power control, the power on the reverse linkof CDMA2000 is also controlled through an Open Loop Power Controlmechanism. This mechanism inverses the slow fading effect due to pathloss and shadowing. It also acts as a safety fuse when the fast powercontrol fails. When the forward link is lost, the closed loop reverse linkpower control is "freewheeling" and the terminal disruptively interfereswith neighboring. In such a case, the open loop reduces the terminaloutput power and limits the impact to the system. Finally the Outer LoopPower drives the closed loop power control to the desired set point basedon error statistics that it collects from the forward link or reverse link.Due to the expanded data rate range and various QoS requirements,different users will have different outer loop thresholds; thus, differentusers will receive different power levels at the base station. In the reverselink, CDMA2000 defines some nominal gain offsets based on variouschannel frame format and coding schemes. The remaining differenceswill be corrected by the outer loop itself.Soft Hand-offEven with dedicated channel operation, the terminal keeps searching fornew cells as it moves across the network. In addition to the active set,neighbor set, and remaining set, the terminal also maintains a candidateset.When a terminal is traveling in a network, the pilot from a new BTS (P2)strength exceeds the minimum threshold TADD for addition in the activeset. However, initially its relative contribution to the total received signalstrength is not sufficient and the terminal moves P2 to the candidate set.The decision threshold for adding a new pilot to the active set is definedby a linear function of signal strength of the total active set. The networkdefines the slope and cross point of the function. When strength of P2 isdetected to be above the dynamic threshold, the terminal signals thisevent to the network. The terminal then receives a hand-off directionmessage from the network requesting the addition of P2 in the active set.The terminal now operates in soft hand-off.The strength of serving BTS (P1) drops below the active set threshold,meaning P1 contribution to the total received signal strength does notjustify the cost of transmitting P1. The terminal starts a hand-off droptimer. The timer expires and the terminal notifies the network that P1dropped below the threshold. The terminal receives a hand-off messagefrom the network moving P1 from the active set to the candidate set.Then P1 strength drops below TDROP and the terminal starts a hand-offdrop timer, which expires after a set time. P1 is then moved from ١٠٥
  • 106. Mobile Evolution to 3Gcandidate set to neighbor set. This step-by-step procedure with multiplethresholds and timers ensures that the resource is only used whenbeneficial to the link and pilots are not constantly added and removedfrom the various lists, therefore limiting the associated signaling.In addition to intrasystem, intrafrequency monitoring, the network maydirect the terminal to look for base stations on a different frequency or adifferent system. CDMA2000 provides a framework to the terminal insupport of the inter- frequency handover measurements consisting ofidentity and system parameters to be measured. The terminal performsrequired measurements as allowed by its hardware capability.In case of a terminal with dual receiver structure, the measurement can bedone in parallel. When a terminal has a single receiver, the channelreception will be interrupted when performing the measurement. In thisinstance, during the measurement, a certain portion of a frame will belost. To improve the chance of successful decoding, the terminal isallowed to bias the FL power control loop and boost the RL transmitpower before performing the measurement. This method increases theenergy per information bit and reduces the risk of losing the link in theinterval. Based on measurement reports provided by the terminal, thenetwork then decides whether or not to hand-off a given terminal to adifferent frequency system. It does not release the resource until itreceives confirmation that hand-off was successful or the timer expires.This enables the terminal to come back in case it could not acquire thenew frequency or the new system.Transmit DiversityTransmit diversity consists of de-multiplexing and modulating data intotwo orthogonal signals, each of them transmitted from a different antennaat the same frequency. The two orthogonal signals are generated usingeither Orthogonal Transmit Diversity (OTD) or Space-Time Spreading(STS). The receiver reconstructs the original signal using the diversitysignals, thus taking advantage of the additional space and/or frequencydiversity.Another transmission option is directive transmission. The base stationdirects a beam towards a single user or a group of users in a specificlocation, thus providing space separation in addition to code separation.Depending on the radio environment, transmit diversity techniques mayimprove the link performance by up to 5 dB. ١٠٦
  • 107. Mobile Evolution to 3GVoice and Data ChannelsThe CDMA2000 forward traffic channel structure may include severalphysical channels: • The Fundamental Channel (F-FCH) is equivalent to functionality Traffic Channel (TCH) for IS-95. It can support data, voice, or signaling multiplexed with one another at any rate from 750 bps to 14.4 kbps. • The Supplemental Channel (F-SCH) supports high rate data services. The network may schedule transmission on the F-SCH on a frame-by- frame basis, if desired. • The Dedicated Control Channel (F-DCCH) is used for signaling or bursty data sessions. This channel allows for sending the signaling information without any impact on the parallel data stream.The reverse traffic channel structure is similar to the forward trafficchannel. It may include R-PICH, a Fundamental Channel (R-FCH),and/or a Dedicated Control Channel (R-DCCH), and one or severalSupplemental Channels (R-SCH). Their functionality and encodingstructure is the same as for the forward link with data rates ranging from1 kbps to 1 Mbps (It is important to note that while the standard supportsa maximum data rate of 1 Mbps, existing products are supporting a peakdata rate of 307 kbps).Traffic ChannelThe traffic channel structure and frame format is very flexible. In order tolimit the signaling load that would be associated with a full frame formatparameter negotiation, CDMA2000 specifies a set of channelconfigurations. It defines a spreading rate and an associated set of framesfor each configuration.The forward traffic channel always includes either a fundamental channelor a dedicated control channel. The main benefit of this multichannelforward traffic structure is the flexibility to independently set up and teardown new services without any complicated multiplexing reconfigurationor code channel juggling. The structure also allows different hand-offconfigurations for different channels. For example, the F-DCCH, whichcarries critical signaling information, may be in soft hand-off, while theassociated F-SCH operation could be based on a best cell strategy.Supplemental ChannelsOne key CDMA2000 1X feature is the ability to support both voice anddata services on the same carrier. CDMA2000 operates at up to 16 or 32times the FCH rate-also referred to as 16x or 32x in Release 0 and A, ١٠٧
  • 108. Mobile Evolution to 3Grespectively. In contrast to voice calls, the traffic generated by packet datacalls is bursty, with small durations of high traffic separated by largerdurations of no traffic. It is very inefficient to dedicate a permanent trafficchannel to a packet data call. This burstiness impacts the amount ofavailable power to the voice calls, possibly degrading their quality if thesystem is not engineered correctly. Hence, a key CDMA2000 designissue is assuring that a CDMA channel carrying voice and data callssimultaneously do so with negligible impact to the QoS of both.Supplemental Channels (SCHs) can be assigned and deassigned at anytime by the base station. The SCH has the additional benefit of improvedmodulation, coding, and power control schemes. This allows a singleSCH to provide a data rate of up to 16 FCH in CDMA2000 Release 0 (or153.6 kbps for Rate Set 1 rates), and up to 32 FCH in CDMA2000Release A (or 307.2 kbps for Rate Set 1 rates). Note that each sector of abase station may transmit multiple SCHs simultaneously if it hassufficient transmit power and Walsh codes. The CDMA2000 standardlimits the number of SCHs a mobile station can support simultaneously totwo. This is in addition to the FCH or DCCH, which are set up for theentire duration of the call since they are used to carry signaling andcontrol frames as well as data. Two approaches are possible: individuallyassigned SCHs, with either finite or infinite assignments, or shared SCHswith infinite assignments.For bursty and delay-tolerant traffic, assigning a few scheduled fat pipesis preferable to dedicating many thin or slow pipes. The fat-pipe approachexploits variations in the channel conditions of different users tomaximize sector throughput. The more sensitive the traffic becomes todelay, such as voice, the more appropriate the dedicated traffic channelapproach becomes.TurbocodingCDMA2000 provides the option of using either turbo coding orconvolutional coding on the forward and reverse SCHs. Both codingschemes are optional for the base station and the mobile station, and thecapability of each is communicated through signaling messages prior tothe set up of the call. In addition to peak rate increase and improved rategranularity, the major improvement to the traffic channel coding inCDMA2000 is the support of turbo coding at rate 1/2, 1/3, or 1/4. The ١٠٨
  • 109. Mobile Evolution to 3Gturbo code is based on 1/8 state parallel structure and can only be used forsupplemental channels and frames with more than 360 bits. Turbo codingprovides a very efficient scheme for data transmission and leads to betterlink performance and system capacity improvements. In general, turbocoding provides a performance gain in terms of power savings overconvolutional coding. This gain is a function of the data rate, with higherdata rates generally providing more turbo coding gain. ١٠٩