High Speed Cellular Technologies over the Internet Guide : Prof. A. Sahoo
Outline <ul><li>Introduction to 1G and 2G Technologies. </li></ul><ul><ul><li>GSM & CDMA. </li></ul></ul><ul><li>2.5G Tech...
1G Technologies <ul><li>Analog cellphone standard introduced in 1980. </li></ul><ul><li>Radio signal used were analog. </l...
2G Technologies <ul><li>GSM. </li></ul><ul><ul><li>Global System for Mobile communications. </li></ul></ul><ul><ul><li>Dig...
GSM Architecture Source : www.gsmworld.com
GMSK <ul><li>In FSK the digital information is transmitted through discrete frequency changes of a carrier wave. </li></ul...
2G Technologies <ul><li>CDMA. </li></ul><ul><ul><li>Code Division Multiple Access. </li></ul></ul><ul><ul><li>Data rates a...
2.5G Technologies <ul><li>Motivation </li></ul><ul><ul><li>2G Technologies are Circuit Switched in which bandwidth  remain...
2.5G Technologies <ul><li>Advantages </li></ul><ul><ul><li>Provides data rate comparable to 3G. </li></ul></ul><ul><ul><li...
<ul><li>General Packet Radio Service. </li></ul><ul><li>GSM Infrastructure Enhancement. </li></ul><ul><li>Packet-oriented ...
GPRS continued <ul><li>Users will pay for actual data transmitted not for the connection time. </li></ul><ul><li>No change...
Source : WS 03/04, TKN TU Berlin, Cornelia Kappler
EDGE <ul><li>Enhanced data rates for GSM evolution. </li></ul><ul><li>GSM/GPRS-Network Enhancementr </li></ul><ul><li>Data...
EDGE continued... <ul><li>Link adaptation scheme is EDGE regularly estimate the link quality and select the appropriate mo...
PSK <ul><li>Phase shift keying is a digital modulation scheme that conveys data by modulating  the phase of the carrier wa...
8-PSK Source : www.gsmworld.com
Why 2.5G Provides Higher Data Rate <ul><li>Packet data capabilities are added in GPRS. </li></ul><ul><li>Some additional n...
3G Technologies <ul><li>Based on ITU standard IMT-2000 </li></ul><ul><li>3G capabilities mainly means supporting higher bi...
IMT - 2000 <ul><li>International Mobile Telecommunications. </li></ul><ul><li>Operates at the frequency of 2000 Mhz. </li>...
UMTS <ul><li>Universal Mobile Telecommunications System. </li></ul><ul><li>UTRAN - UMTS Terrestrial Radio Access Network. ...
UMTS Architecture Source : www.iec.org
UMTS Interfaces <ul><ul><li>The Core Network of UMTS is same as that of GPRS. The air interface is totally different.  </l...
UTRAN <ul><ul><li>The UTRAN is the new Radio interface of UMTS. Its constituting element are RNC, Node-B and UE. </li></ul...
W-CDMA <ul><li>W-CDMA is the air interface of UMTS. </li></ul><ul><li>W-CDMA is coming from GSM side </li></ul><ul><li>Is ...
Why 3G Provides Higher Data Rate than 2.5G <ul><li>New radio interface UTRAN is added which connects to the CN via lu inte...
4G Technologies <ul><li>ITU-R will release the requirements of 4G in 2008. </li></ul><ul><li>Could go beyond the cell phon...
4G continued.... <ul><li>Motivation </li></ul><ul><ul><li>The continuing growth of wireless usage. </li></ul></ul><ul><ul>...
4G continued.... <ul><li>According to ITU recomendations 4G should provide data rates of at least 100 Mbps and use OFDMA a...
4G and ITU <ul><li>LTE, UBM and IEEE 802.16m are the principle 4G candidates. </li></ul><ul><li>They work with various ant...
Modulation Used in 4G. <ul><ul><li>QAM (Quadrature amplitude modulation)‏ </li></ul></ul><ul><ul><ul><li>QAM is a modulati...
OFDMA <ul><ul><li>Orthogonal Frequency Division Multiple Access (OFDMA). </li></ul></ul><ul><ul><li>In OFDMA frequency-div...
Long Term Evolution (LTE)‏ <ul><li>3GPP is developing LTE. </li></ul><ul><li>LTE builds on GSM technology thereby easing m...
Ultra Mobile Broadband (UMB)‏ <ul><li>3GPP2 is developing UMB </li></ul><ul><li>Could be deployed in frequency band betwee...
IEEE 802.16m (WIMAX II)‏ <ul><li>Based of IEEE 802.16e (Mobile WIMAX)‏ </li></ul><ul><li>Built on existing OFDMA technolog...
4G 's Future <ul><li>Barriers </li></ul><ul><ul><li>Cost will hinder adoption </li></ul></ul><ul><ul><li>To achieve this h...
WiMax 802.16d <ul><li>Worldwide interoperability for microwave access. </li></ul><ul><li>MAN technology based on standards...
Physical Layer <ul><li>Operates in the frequency band of 2-11 Ghz. </li></ul><ul><li>256-carrier OFDM scheme is used </li>...
Modulation Vs Bit Rate Source : References [1]
Future Enhancements to 802.16 <ul><li>Spatial multiplexing </li></ul><ul><ul><li>Also known as MIMO. </li></ul></ul><ul><u...
Conclusion <ul><li>WiMax(802.16d/e) becomes a competitor against 3GPP 3.5G(HSDPA, High Speed Downlink Packet Access) for 4...
References <ul><ul><li>A. Ghosh and D. R.Wolter SBC labs & J.G.Andrews and Runhua chen University of Texas, “ Broadband Wi...
References <ul><ul><li>UMTS World :  www.umtsworld.com   </li></ul></ul><ul><ul><li>www.iec.org . </li></ul></ul><ul><ul><...
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High Speed Cellular Technologies Over The Internet

  1. 1. High Speed Cellular Technologies over the Internet Guide : Prof. A. Sahoo
  2. 2. Outline <ul><li>Introduction to 1G and 2G Technologies. </li></ul><ul><ul><li>GSM & CDMA. </li></ul></ul><ul><li>2.5G Technologies. </li></ul><ul><ul><li>GPRS & EDGE . </li></ul></ul><ul><li>3G Technologies. </li></ul><ul><ul><li>W-CDMA (UMTS), HSDPA & MBMS. </li></ul></ul><ul><li>4G Technologies. </li></ul><ul><ul><li>LTE, UMB & WIMAX . </li></ul></ul>
  3. 3. 1G Technologies <ul><li>Analog cellphone standard introduced in 1980. </li></ul><ul><li>Radio signal used were analog. </li></ul><ul><ul><li>voice during a call is modulated to high frequency 150 MHz. </li></ul></ul><ul><li>AMPS (Advanced mobile phone systems) </li></ul><ul><ul><li>Based on FDMA. </li></ul></ul><ul><ul><li>Developed by Bell Labs and deployed in US in 1983. </li></ul></ul><ul><ul><li>No longer exists in the market. </li></ul></ul>
  4. 4. 2G Technologies <ul><li>GSM. </li></ul><ul><ul><li>Global System for Mobile communications. </li></ul></ul><ul><ul><li>Digital cellphone standard. </li></ul></ul><ul><ul><li>Operate in the 900 MHz or 1800 MHz bands. </li></ul></ul><ul><ul><li>Based on TDMA. </li></ul></ul><ul><ul><li>Generally offer data rates of 9.6 kbps. </li></ul></ul><ul><ul><li>Splits the frequency band into multiple channels and increases each channel bandwidth by dividing it into multiple time slots. </li></ul></ul><ul><ul><li>Modulation based on GMSK a variant of FSK. </li></ul></ul>
  5. 5. GSM Architecture Source : www.gsmworld.com
  6. 6. GMSK <ul><li>In FSK the digital information is transmitted through discrete frequency changes of a carrier wave. </li></ul><ul><li>MSK is spectrally efficient form of FSK. </li></ul><ul><li>In MSK the difference between the higher and lower frequency is identical to half the bit rate. As a result, the waveforms used to represent a 0 and a 1 bit differ by exactly half a carrier period. </li></ul><ul><li>In GMSK the digital data stream is first shaped with a Gaussian filter. </li></ul>Source: Wikipedia.org
  7. 7. 2G Technologies <ul><li>CDMA. </li></ul><ul><ul><li>Code Division Multiple Access. </li></ul></ul><ul><ul><li>Data rates are 14.4Kbps to 115K bps. </li></ul></ul><ul><ul><li>Assign codes to seperate transmission which can then run at the same time on a single channel spread across a wide range of radio frequencies. </li></ul></ul><ul><ul><li>Each receiver decodes only the transmission it is supposed to work with. </li></ul></ul><ul><ul><li>CDMA permits several radios to share the same frequencies. </li></ul></ul>
  8. 8. 2.5G Technologies <ul><li>Motivation </li></ul><ul><ul><li>2G Technologies are Circuit Switched in which bandwidth remains idle ample amount of time during communication. </li></ul></ul><ul><ul><li>Why not use this idle time to transfer packets. </li></ul></ul><ul><ul><li>Transfering Packets is Cheaper. </li></ul></ul><ul><li>Use Existing infrastructure while adding some additional node which provide packet functionality to the network </li></ul><ul><li>Evolved During the transition of TDMA based 2G systems to 3G systems. </li></ul>
  9. 9. 2.5G Technologies <ul><li>Advantages </li></ul><ul><ul><li>Provides data rate comparable to 3G. </li></ul></ul><ul><ul><li>Work on the same spectrum allocated to 2G. </li></ul></ul><ul><ul><li>provide an opporunity to players to compete who do not want to invest heavily in 3G. </li></ul></ul><ul><ul><li>GPRS & EDGE are the main drivers. </li></ul></ul>
  10. 10. <ul><li>General Packet Radio Service. </li></ul><ul><li>GSM Infrastructure Enhancement. </li></ul><ul><li>Packet-oriented Data Service. </li></ul><ul><li>Allows IP packets to be sent and received across mobile networks. </li></ul><ul><li>Theoretical maximum speed: 171.2 kbps using all 8 time slots. </li></ul><ul><li>Developed for optimum usage of radio resource which is scrace. </li></ul><ul><li>Small step compared to building a totally new 3G IMT-2000 network. </li></ul>GPRS
  11. 11. GPRS continued <ul><li>Users will pay for actual data transmitted not for the connection time. </li></ul><ul><li>No change in air interface & modulation scheme this is also a limitation for even higher data rate. </li></ul><ul><li>Base Station Subsystem consist of Base Station Controller (BSC) & Packet Control Unit (PCU). </li></ul><ul><li>PCU support all GPRS protocols for communication over the air interface. </li></ul><ul><li>Introduced two new nodes SGSN & GGSN and HLR is enhanced with GPRS subscriber data and routing information. </li></ul>
  12. 12. Source : WS 03/04, TKN TU Berlin, Cornelia Kappler
  13. 13. EDGE <ul><li>Enhanced data rates for GSM evolution. </li></ul><ul><li>GSM/GPRS-Network Enhancementr </li></ul><ul><li>Datarate compareable to UMTS Network (384 kBit/s and more). </li></ul><ul><li>Changing GSM Modulation from GMSK to 8PSK. </li></ul><ul><li>16-QAM was also proposed for EDGE. </li></ul><ul><li>EDGE provide both PS & CS services. </li></ul><ul><li>QoS profile is defined for each sevice with QoS parameters include priority, reliability & delay. </li></ul>
  14. 14. EDGE continued... <ul><li>Link adaptation scheme is EDGE regularly estimate the link quality and select the appropriate modulation and coding scheme to maximize the user bit rate. </li></ul><ul><li>Incremental redundancy is also used. </li></ul><ul><li>RLC/MAC layer of GPRS need to be modified to accomodate features for multiplexing & link adaptation. </li></ul>
  15. 15. PSK <ul><li>Phase shift keying is a digital modulation scheme that conveys data by modulating the phase of the carrier wave. </li></ul><ul><li>PSK uses a finite number of phases, each assigned a unique pattern of binary bits (symbol). </li></ul><ul><li>The demodulator determines the phase of the received signal and maps it back to the symbol. </li></ul><ul><li>BPSK uses 2 phases to transmit data (0's and 1's). </li></ul><ul><ul><li>Able to transmit 1 bit per symbol. </li></ul></ul><ul><li>QPSK (4-PSK) uses 4 phases to transmit data thus forming 4 symbols (00,01,10,11). </li></ul><ul><li>8-PSK uses eight phases forming 8 symbols and is the highest order PSK constellation </li></ul><ul><ul><li>Able to transmit 3 bit per symbol. </li></ul></ul>
  16. 16. 8-PSK Source : www.gsmworld.com
  17. 17. Why 2.5G Provides Higher Data Rate <ul><li>Packet data capabilities are added in GPRS. </li></ul><ul><li>Some additional nodes are added in architecture to facilitate IP functionality. </li></ul><ul><li>In EDGE the modulation scheme is changed to 8-PSK while GSM uses GMSK. </li></ul><ul><li>GSM uses GMSK modulation that can send 1 bit per symbol while EDGE uses 8-PSK which transmits 3 bits per symbol. </li></ul>
  18. 18. 3G Technologies <ul><li>Based on ITU standard IMT-2000 </li></ul><ul><li>3G capabilities mainly means supporting higher bit rates. </li></ul><ul><li>3G capabilities implies the addition of </li></ul><ul><ul><li>Packet Switched Services. </li></ul></ul><ul><ul><li>internet Access & IP Connectivity. </li></ul></ul><ul><li>Provide service at 2 Mbps for stationary users and 384 Kbps for mobile users. </li></ul><ul><li>3G standards are W-CDMA (UMTS) and CDMA-2000. </li></ul>
  19. 19. IMT - 2000 <ul><li>International Mobile Telecommunications. </li></ul><ul><li>Operates at the frequency of 2000 Mhz. </li></ul><ul><li>Bandwidth upto 2000 Mbps. </li></ul><ul><li>Basic services of IMT-2000 network </li></ul><ul><ul><li>High-quality voice transmission. </li></ul></ul><ul><ul><li>Messaging (e-mail, fax, sms, chat). </li></ul></ul><ul><ul><li>Multimedia (playing music, videos). </li></ul></ul><ul><ul><li>Internet access (surfing). </li></ul></ul>
  20. 20. UMTS <ul><li>Universal Mobile Telecommunications System. </li></ul><ul><li>UTRAN - UMTS Terrestrial Radio Access Network. </li></ul><ul><li>UMTS system uses the same core network as the GPRS and uses entirely new radio interface UTRAN. </li></ul><ul><li>UMTS Multiplexing </li></ul><ul><ul><li>Wideband CDMA for air interface. </li></ul></ul><ul><li>Up/Downlink Frequency </li></ul><ul><ul><li>Uplink: 1920 – 1980MHz. </li></ul></ul><ul><ul><li>Downlink: 2110 - 2170MHz. </li></ul></ul><ul><li>The UE is connected to Node-B over high speed Uu (up to 2 Mbps) Interface. </li></ul>
  21. 21. UMTS Architecture Source : www.iec.org
  22. 22. UMTS Interfaces <ul><ul><li>The Core Network of UMTS is same as that of GPRS. The air interface is totally different. </li></ul></ul><ul><ul><li>Uu: UE to Node B (UTRA, the UMTS W-CDMA air interface. </li></ul></ul><ul><ul><li>Iu: RNC to GSM Phase 2+ CN interface (MSC/VLR or SGSN)‏ </li></ul></ul><ul><ul><ul><li>Iu-CS for circuit-switched data. </li></ul></ul></ul><ul><ul><ul><li>Iu-PS for packet-switched data. </li></ul></ul></ul><ul><ul><li>Iub: RNC to Node B interface. </li></ul></ul><ul><ul><li>Iur: RNC to RNC interface, not comparable to any interface in GSM. </li></ul></ul>
  23. 23. UTRAN <ul><ul><li>The UTRAN is the new Radio interface of UMTS. Its constituting element are RNC, Node-B and UE. </li></ul></ul><ul><ul><li>RNC </li></ul></ul><ul><ul><ul><li>The RNCs enables autonomous radio resource management (RRM) by UTRAN. </li></ul></ul></ul><ul><ul><ul><li>RNCs also assist in Soft Handover of the UEs. </li></ul></ul></ul><ul><ul><li>Node B </li></ul></ul><ul><ul><ul><li>The Node-B is physical unit of radio transmission /reception with cells. </li></ul></ul></ul><ul><ul><ul><li>It connects to UE via Uu W-CDMA radio interface and RNC via Iub ATM interface. </li></ul></ul></ul><ul><ul><ul><li>The main task of Node B is forward error correction (FEC), rate adaptation, W-CDMA spreading /despreading, and quadrature phase shift keying (QPSK) modulation on the air interface. </li></ul></ul></ul>
  24. 24. W-CDMA <ul><li>W-CDMA is the air interface of UMTS. </li></ul><ul><li>W-CDMA is coming from GSM side </li></ul><ul><li>Is a part of 3GPP and used in UMTS systems. </li></ul><ul><li>Utilizes the direct sequence Code Division Multiple Access signalling method to achieve higher speeds and support more users </li></ul><ul><li>Radio channels are 5MHz wide.. </li></ul><ul><li>Release 5 came out in 2002 introduced improved support for downlink packet data (HSPDA). </li></ul><ul><li>Release 6 in 05 impoved packet capabilities in Uplink MBMS. </li></ul>
  25. 25. Why 3G Provides Higher Data Rate than 2.5G <ul><li>New radio interface UTRAN is added which connects to the CN via lu interface. </li></ul><ul><li>Introduction of IP based multimedia service in the core network. </li></ul>
  26. 26. 4G Technologies <ul><li>ITU-R will release the requirements of 4G in 2008. </li></ul><ul><li>Could go beyond the cell phone and provide mobile data services to consumer electronics & other devices. </li></ul><ul><li>Example are sending of photos from camera to printer. </li></ul><ul><li>All 4G technologies will be IP-based & packet-switched. </li></ul><ul><li>Spectrally efficient modulation schemes have been developed but they wont work with existing 3G as it requires recievers to work with more complex technology Example 64 QAM. </li></ul><ul><li>The 4G Technology would enable IP-based voice, data and streaming multimedia theoretically at the speed of 288 Mbps. </li></ul>
  27. 27. 4G continued.... <ul><li>Motivation </li></ul><ul><ul><li>The continuing growth of wireless usage. </li></ul></ul><ul><ul><li>Rise of household broadband internet subscription. </li></ul></ul><ul><ul><li>Users want wireless technolgy that approximate the experience they have at home. </li></ul></ul><ul><ul><li>Demand for better quality faster video viewing and quicker downloading even for mobile users with handheld devices. </li></ul></ul>
  28. 28. 4G continued.... <ul><li>According to ITU recomendations 4G should provide data rates of at least 100 Mbps and use OFDMA a multiuser version of OFDM. </li></ul><ul><li>OFDM increases bandwidth by splitting data-bearing radio signal into smaller signal sets and modulating each onto a different subcarrier, transmitting them simultaneously at different frequencies. </li></ul><ul><li>The subcarriers are spaced orthogonally. </li></ul><ul><li>64 QAM is higher order modulation scheme in which each transmitted unit conveys 6 data bits compared to 16 QAM 4 and 8-PSK 3 bits. </li></ul>
  29. 29. 4G and ITU <ul><li>LTE, UBM and IEEE 802.16m are the principle 4G candidates. </li></ul><ul><li>They work with various antenna approaches including MIMO which uses multiple antennas at transmitter & receiver to improve performance. </li></ul><ul><li>ITU-R will select candidate technology in 2008 or 09 and develope detailed specifications in 2009-10. </li></ul><ul><li>Vendors begin implementation between 2010-12 with wide deployment occuring by 2015. </li></ul>
  30. 30. Modulation Used in 4G. <ul><ul><li>QAM (Quadrature amplitude modulation)‏ </li></ul></ul><ul><ul><ul><li>QAM is a modulation scheme which conveys data by modulating the amplitude of two carrier waves. </li></ul></ul></ul><ul><ul><ul><li>These two waves are out of phase to each other. </li></ul></ul></ul><ul><ul><ul><li>Example of 4-QAM. </li></ul></ul></ul><ul><ul><ul><li>64 QAM can send 6 bits at a time. </li></ul></ul></ul><ul><ul><li>OFDM (Orthogonal frequency divison multiplexing)‏ </li></ul></ul><ul><ul><ul><li>OFDM is a is a digital multi-carrier modulation scheme, which uses a large number of closely-spaced orthogonal sub-carriers to carry data. </li></ul></ul></ul><ul><ul><ul><li>These sub-carriers typically overlap in frequency. </li></ul></ul></ul><ul><ul><ul><li>Each sub-carrier is modulated with a conventional modulation scheme as 64-QAM. </li></ul></ul></ul>
  31. 31. OFDMA <ul><ul><li>Orthogonal Frequency Division Multiple Access (OFDMA). </li></ul></ul><ul><ul><li>In OFDMA frequency-division multiple access is achieved by assigning different OFDM sub-channels to different users. </li></ul></ul><ul><ul><li>OFDMA supports differentiated quality-of-service by assigning different number of sub-carriers to different users in a similar fashion as in CDMA. </li></ul></ul>
  32. 32. Long Term Evolution (LTE)‏ <ul><li>3GPP is developing LTE. </li></ul><ul><li>LTE builds on GSM technology thereby easing migration for the many providers – but uses OFDM based air-interface. </li></ul><ul><li>Provides Spectrum flexibility i.e can be deployed in frequency band between 1.25 & 20 Mhz wide </li></ul><ul><li>Maximum data rate is expected to be 250 Mbps in a channel 20-Mhz wide. </li></ul>
  33. 33. Ultra Mobile Broadband (UMB)‏ <ul><li>3GPP2 is developing UMB </li></ul><ul><li>Could be deployed in frequency band between 1.25 & 20 Mhz wide. </li></ul><ul><li>UMB offers data rates for mobile users 288 Mbps downstream & 75 Mbps upstream using 20 Mhz channels. </li></ul><ul><li>The technology would provide a transition path for CDMA based carriers. </li></ul>
  34. 34. IEEE 802.16m (WIMAX II)‏ <ul><li>Based of IEEE 802.16e (Mobile WIMAX)‏ </li></ul><ul><li>Built on existing OFDMA technology. </li></ul><ul><li>Operates in frequencies between 10 and 66 Ghz. </li></ul><ul><li>Offer data rates upto 100 Mbps for mobile application and 1 Gbps for stationary users </li></ul>
  35. 35. 4G 's Future <ul><li>Barriers </li></ul><ul><ul><li>Cost will hinder adoption </li></ul></ul><ul><ul><li>To achieve this higher speed the carriers would have to transmit over wide frequency slices which would be difficult because of limited spectrum availability. </li></ul></ul><ul><ul><li>Carriers are still recovering their cost they have invested in 3G. </li></ul></ul><ul><li>Advantages </li></ul><ul><ul><li>Transmission cost are lower for wireless technologies which are spectrally efficient as 4G promises to be. </li></ul></ul>
  36. 36. WiMax 802.16d <ul><li>Worldwide interoperability for microwave access. </li></ul><ul><li>MAN technology based on standards in IEEE 802.16 specification. </li></ul><ul><li>Used for fixed wireless access with substantially higher bandwidth than most cellular networks. </li></ul><ul><li>Uses orthogonal frequency division multiplexing. </li></ul><ul><li>802.16 will offer a mobile & quickly deployable alternative (Mobile Wimax) to cabled access networks. </li></ul><ul><li>802.16 will provide mobilty upto 70/80 mi/hr. </li></ul>
  37. 37. Physical Layer <ul><li>Operates in the frequency band of 2-11 Ghz. </li></ul><ul><li>256-carrier OFDM scheme is used </li></ul><ul><li>OFDM is a digital multi-carrier modulation scheme, which uses a large number of closely-spaced orthogonal sub-carriers to carry data </li></ul><ul><li>These sub-carriers typically overlap in frequency, but are designed not to interfere with each other </li></ul><ul><li>Each sub-carrier is modulated with a conventional modulation scheme (such as QAM). </li></ul><ul><li>Adaptive modulation and coding is used. </li></ul>
  38. 38. Modulation Vs Bit Rate Source : References [1]
  39. 39. Future Enhancements to 802.16 <ul><li>Spatial multiplexing </li></ul><ul><ul><li>Also known as MIMO. </li></ul></ul><ul><ul><li>Increases the data rate in proportion to number of transmit antennas. </li></ul></ul><ul><li>Hybrid ARQ </li></ul><ul><ul><li>Uses an error control code in conjunction with the retransmission to ensure realiability. </li></ul></ul><ul><ul><li>Subsequent retransmissions are combined with the previous transmissions to improve reliability. </li></ul></ul><ul><ul><li>HARQ greatly increases the data rate. </li></ul></ul>
  40. 40. Conclusion <ul><li>WiMax(802.16d/e) becomes a competitor against 3GPP 3.5G(HSDPA, High Speed Downlink Packet Access) for 4G wireless technology </li></ul><ul><ul><li>WiMAXwill take over the 3G networks and become the 4G wireless technology –AT&T. </li></ul></ul><ul><li>The high cost of adoption may cause hinderance initially but the 4G networks will capture the market by 2015. </li></ul><ul><li>To further increase the data rates above 4G we need to improve the modulation techniques as the spectrum is already congested and limited. </li></ul><ul><li>Backward compatability and Interoperability among different technologies & networks will be the important factor after the Introduction of 4G. </li></ul>
  41. 41. References <ul><ul><li>A. Ghosh and D. R.Wolter SBC labs & J.G.Andrews and Runhua chen University of Texas, “ Broadband Wireless Access with WiMax/802.16,” IEEE Communication Magazine, Feb 2005. </li></ul></ul><ul><ul><li>Sixto Ortiz Jr , “4G Wireless Begins to Take Shape,” IEEE Computer Society Nov 2007. </li></ul></ul><ul><ul><li>S.Parkvall, E. Englund, Lundevall, and J. Torsner Ericsson Research, “Evolving 3G Mobile Systems WCDMA,” IEEE Communication Magazine Feb 2006. </li></ul></ul><ul><ul><li>TE Kolding, KI Pedersen, J. Wigard, F. Frederiksen & PE Mogensen Nokias Networks, “High Speed Downlink Packet Access: WCDMA Evolution, ” IEEE Vehicular Technology Society News FEB 2003. </li></ul></ul><ul><ul><li>GSM World : www.gsmworld.com . </li></ul></ul>
  42. 42. References <ul><ul><li>UMTS World : www.umtsworld.com </li></ul></ul><ul><ul><li>www.iec.org . </li></ul></ul><ul><ul><li>www.wikipedia.org. </li></ul></ul>
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