Modern Wireless Communication System

Dinesh Suresh Bhadane
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Chapter-4
Modern Wireless Communication
System

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4.1 Evolution for 2.5 G TDMA
standards [12]
 HSCSD for 2.5 G GSM
 GPRS for 2.5 G GSM and IS-136
 EDGE for 2.5G GSM and IS-136
 IS-95B for 2.5 G CDMA.
4.2 IMT 2000 [04]
 IMT 2000 Vision and Evolution
Aspects.
 Radio Spectrum for IMT -2000

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 Mr. D. S. Bhadane
 Qualifications
 2016: ME (VLSI & Embedded System)
(SPPU, Pune) Distinction
 2012: BE (E&TC) (University of Pune)
Distinction
 Experience
 Industrial: 0 years
 Academic: 5 years
 dinesh.bhadane@sandippolytechnic.org

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Student will be able to
List out features of 2.5 G GSM Standards HSCSD, GPRS
and IS-136,EDGE and IS 95B.
State features of IMT 2000 Radio spectrum, vision and
Evolution.

© 2015, YCMOU, Nashik. Visit Us: www.ycmou.ac.in
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List four features of HSCSD for 2.5 GSM system.

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High-Speed Circuit-Switched Data
Enhancement of CSD (Circuit-Switched Data) standard
It is a specification for data transfer over GSM networks
First attempt to get high-speed data over GSM
It is a Circuit Switching technology (Circuit switched ⇒ Constant
data rate)
TDMA-based
Offers symmetric or asymmetric data rates.

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HSCSD utilizes up to four 9.6Kb or 14.4Kb time slots
Theoretical bandwidth: 115.2Kbps (8 x 14.4Kbps per timeslot)
Practical bandwidth: 57.6Kbps (4 time slots)
Data rates up to 115 kbps
It is limited to 38.4Kbps on 900Mhz GSM networks.
It can only achieve 57.6Kbps on 1800Mhz GSM networks.
Supports guaranteed quality of service.
It bundles up to 8 GSM traffic channels into one high speed
Channel.

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Lower latency
No need for RTS/CTS
It is a better protocol for timing-sensitive applications such as image
or video transfer.
For an application such as downloading, HSCSD may be preferred,
since circuit-switched data is usually given priority over packet-
switched data on a mobile network, and there are few seconds when
no data is being transferred.
Takes care of Error Control Coding Algorithm.

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Less bandwidth efficient
Expensive wireless links than GPRS
Not suitable for bursty data
Not widely implemented
Not suitable for variable data rate applications.
Only needs the service provider to implement a software
changes at existing GSM base stations.

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Telefax
Image or video transfer
Downloading
Real Time Interactive web sessions
Dedicated streaming Internet Access

11
List four specifications of GPRS 2.5 G GSM standard.

12
Compare GPRS with IS-136. (Any four points)

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 General Packet Radio Service
 Packet-based data network.
 It will be the first service available to offer full instant wireless access
to the Web.
 Support many users (multiuser) than HSCSD, but in a bursty manner.
 Shares individual Radio Channels and Time Slots.
 Provides continuous connection to the Internet for mobile phone and
computer Users.
 Transmission rates - 115Kbps to 171Kbps.

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 The GPRS standard provides a packet network on dedicated GSM or IS-136 radio
channels.
 It retains the original modulation formats specified in the original 2G TDMA
standards.
 Uses a completely redefined air interface in order to better handle packet data access.
 When all 8 time slots of a GSM radio channel are dedicated to GPRS, an individual
user is able to achieve as much as 171.2 kbps (8 time slots * 21.4 kbps of raw
uncoded data throughput).
 GPRS was originally designed to provide a packet data overlay solely for GSM
networks, but at the request of North American IS-136 operators, GPRS was
extended to include both TDMA standards.

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 Users are always connected and online
 Users will be charged only for the amount of data that is transported.
 User is able to download much more data than that it uploads on the internet.
 GPRS Subscribers are automatically tune to dedicated GPRS radio channels
and particular time slots for “Always On” access to the network.
 For GSM providers, this new technology will increase data rates of both
circuit switching [HSCSD] and packet switching (GPRS) by a factor of 10 to
15 times .
 Provides their own error correction schemes.

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 Data throughput decreases when more users attempt to use the network.
 Installation of GPRS requires the GSM operators to install new routers and
Internet gateways at the base station and new software that redefines the base
station air interface standard for GPRS channels and time slots.

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Non-real time Internet usage
Retrieval of email, faxes and asymmetric web browsing

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For EDGE 2.5 G And GPRS Standard State Following Specification (2.5 G GSM) (i)
Data Rate (ii) Channel Bandwidth (iii) Modulation Technique (iv) Number of Voice
Channels.

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Explain EDGE system for 2.5 GSM.

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List the following specifications of EDGE 2.5 G standard.
(1) Backward compatibility (2) Channel bandwidth (3) Data rate (4)
Duplexing method
Ans- Specifications of EDGE 2.5 G standard
1) Backward compatibility – GSM
2) Channel bandwidth – 200 KHz
3) Data rate – 547.2 kbps
4) Duplexing method - FDD

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 Enhanced Data rates for GSM (or Global) Evolution
 EDGE is sometimes referred to as Enhanced GPRS, or EGPRS.
 It is a more advanced upgrade to the GSM standard
 Requires the addition of new hardware and software at existing base
stations.
 EDGE introduces a new digital modulation format, 8 -PSK, which is used
in addition to GSM’s standard GMSK modulation.
 EDGE allows for 9 different (autonomously and rapidly selectable) air
interface formats, known as Multiple Modulation And Coding Schemes
(MCS), with varying degrees of error control protection.

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 Each MCS state may use either GMSK (low data rate) or 8 -PSK (high data
rate) modulation for network access, depending on the instantaneous
demands of the network and the operating condition.
 Because of the higher data rates and relaxed error control covering in many
of the selectable air interface format.
 The coverage range is smaller in EDGE than in HSDRC or GPRS.
 EDGE uses the higher order 8 -PSK modulation and a family of MCSs for
each GSM radio channel time slot.
 So that each user connection may adaptively determine the best MCS setting
for the particular radio propagation conditions and data access requirements
of the user.

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 This adaptive capability to select the “best” air interface is called
Incremental Redundancy.
 Due to it, packets are transmitted first with maximum error protection and
maximum data rate throughput, and then subsequent packets are
transmitted with less error protection (usually using punctured
convolutional codes) and less throughput, until the link has an unacceptable
outage or delay.
 Rapid feedback between the base station and subscriber unit then restores
the previous acceptable air interface state, which is presumably at an
acceptable level but with minimum required coding and minimum
bandwidth and power drain.

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Incremental redundancy maximizes the user capacity on the
network by providing acceptable link quality for each user.
When EDGE uses 8-PSK modulation without any error protection,
and all 8 times slots of a GSM radio channel are dedicated to a
single user, a raw peak throughput data rate of 547.2 kbps can be
provided.
By combining the capacity of different radio channels (e.g., using
multicarrier transmissions), EDGE can provide up to several Mbps
of data throughput to individual data users.

25
List the following specifications of IS-136 standard .
1) Frequency Spectrum 2) Channel Bandwidth 3) Data Rate 4)
Modulation Technique

26
List any 4 features of IS-136.

27
Compare IS 95 with IS 136 with respect to any four technical specifications.

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Compare IS-95 B standard with GPRS with respect to following points.
(1) Backward compatibility (2) Channel bandwidth (3) Duplexing tech (4) No. of voice
channels

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State features of IS - 95B (any four)

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 The interim data solution for CDMA is called IS-95B.
 Also known as TIA/EIA-95
 Combines IS-95A, ANSI-J-STD-008 and TSB-74 into a single document.
 CDMA-One IS-95B was first deployed in September 1999 in Korea and has since
been adopted by operators in Japan and Peru.
 It has a single upgrade path for eventual 3G operation.
 It provides high speed packet and circuit switched data access on a common
CDMA radio channel by dedicating multiple orthogonal user channels (Walsh
functions) for specific users and specific purposes.
 The original IS-95 throughput rate specification of 9.6 kbps was not implemented
in practice, but was improved to the current rate of 14.4 kbps as specified in IS-
95A.

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 IS-95B supports Medium Data Rate (MDR) service by allowing a dedicated user to
command up to 8 different user Walsh codes simultaneously and in parallel for an
instantaneous throughput of 115.2 kbps per user (8*14.4 kbps).
 Practical Throughput- 64 kbps is available to a single user in IS-95B due to the slotting
techniques of the air interface.
 IS-95B also specifies hard handoff procedures that allow subscriber units to search
different radio channels in the network without instruction from the switch so that
subscriber units can rapidly tune to different base stations to maintain link quality.
 Prior to IS-95B, the link quality experienced by each subscriber had to be reported back
to the switch through the serving base station several hundreds of times per second, and
at the appropriate moment, the switch would initiate a soft-handoff between the
subscriber and candidate base stations.

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1. State any four features of IMT 2000.
2. State the radio spectrum for IMT-2000. State vision of
FMT-2000 (Four points)
3. List any four visions of IMT 2000.

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 IMT-2000 systems are considerably different from the 2G mobile and PCS.
 It finds usage in wide range of services and offer global mobility.
 The radio interface or radio transmission technology (RTT) deployed in existing wireless
system requires a change to provide the needed spectrum efficiency and capability.
 There are various RTT those have already been developed around the word.
 These technologies were submitted to ITU-R for evaluation and final selection of technology
by the end of year 1999.
 The primary objective of the evaluation is to confirm that all the ITU requirements are
fulfilled and select the RTT that can cover all the radio operating environments with most
commonality.
 The evolution includes higher data rate, WCDMA air interface, WCDMA high speed packet
access integration of other wireless technologies, such as WLAN ALL-IP network evolution.

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 The rapidly growing internet environment and the service requirement in telecommunication
 services requires support for asymmetric ,interactive ,multimedia traffic based on high
speed packet data transport.
 It is therefore necessary to recognize international or global standards for mobile
telecommunication to ensure seamless global mobility and service delivery as well as
integrating the wireline and wireless network to provide telecomm.
 Services transparent to the users.
 IMT 2000 is that global standard to satisfy market demand for mobile services in the ewnty
first century.
 Also known as International Mobile Telecommunications 2000.
 It is the ITU globally coordinated definition of 3G
 Covering key issues such as- frequency spectrum use and technical standards.

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 A worldwide common spectrum (1.8 to 2.2 GHz)
 Global seamless (Smooth or Coherent) roaming
 Enhanced security and performance
 Full integration of wireless(satellite) and wireline (terrestrial ) system
 Increases spectrum efficiency by having flexible radio bearers.
 Multiple environments, not only limited to cellular, but includes: cordless, satellite,
LANs, wireless local loop (WLL)
 Wide range of telecommunications services (data, voice, multimedia, internet etc.)
 Data rates of: For Mega Cell- ≥9.6Kbps, For Macro Cell- ≥144Kbps, For Micro
Cell- ≥ 384Kbps and For (indoor environments) Pico Cell- up to 2Mbps

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 W-CDMA backward compatible with GSM (called UMTS by the ETSI)
 The IS-95 standard (CDMA-One) is evolving its own vision of 3G:
CDMA2000
 The IS-136 standard is evolving its own migration to 3G, Universal Wireless
Communications, UWC-136 or IS-136 HS

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 In 1992 for IMT-2000, the frequency bands 1.885-2.025 GHz and 2.110-2.200 GHz
were allocated.
 Uplink : 1.885-2.025 GHz (mobile satellite services)
 Downlink : 2.110-2.200 GHz (mobile satellite services)
 The terrestrial IMT-2000 networks will work in the following bands:
 Uplink : 1.920-1.980 GHz and downlink: 2.110-2.170 GHz, FDD with mobile
stations transmitting in the lower sub-band.
 Uplink : 1.885-1.920 GHz and downlink : 2.010-2.025 GHz, unpaired for TDD
operation.
 In Europe the TDD band for uplink is from 1885-1900 MHz not available for
licenses use of IMT-2000, this is used by cordless telephony (DECT).

THANK YOU !
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End of Presentation

Modern Wireless Communication System

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