This is the PDF provided by Mr. Achyuta Nanda Mishra on the topic Overview of Wireless Communications

1. Chapter 1. Overview of Wireless Communications
1.1 Introduction
Wireless personal communications:
- any person (properly equipped)
- anywhere
- anytime
- in any format chosen
Copyright Prentice Hall
wireless link
wired link
MS
base station
mobile station
MSC
mobile switching center
BS
MSC
MSC
BS
MS
Backbone Network
Figure 1: An illustration of wireless communications network
Downlink (forward link): from BS to MS
Uplink (reverse link): from MS to BS
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2. Wireless Communications and Networking Ch1 - Page 2 of 8
Definition of radio cell
A radio cell is a geographical area served by a single base station supporting
the services of many mobile stations.
Depending on the size of the area covered, radio cells are categorized into
picocells, microcells, and macrocells.
The main problems in wireless communications come from
- the hostile wireless propagation medium
- user mobility
The wireless channel:
- Multiplicative interference and distortion are normally signal-dependent, including
fading, intersymbol interference, etc. They cause attenuation, mutilation, etc., of
the transmitted signal. The net result is a reduction in usable frequency spectrum.
This form of disturbance cannot be suppressed using filtering.
- Additive noise is not as severe as multiplicative noise, but still reduces signal de-
tectability. Out-of-band noise can be suppressed by filtering, but in-band noise will
still penetrate through the filter.
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3. Wireless Communications and Networking Ch1 - Page 3 of 8
1.2 Wireless Communications Standards
First Generation Analog Cellular Systems:
Region America Europe Japan
Parameter AMPS ETACS NTT
Multiple Access FDMA FDMA FDMA
Duplexing FDD FDD FDD
Forward Channel 869-894 MHz 935-960 MHz 870-885 MHz
Reverse Channel 824-849 MHz 890-915 MHz 925-940 MHz
Channel Spacing 30 kHz 25 kHz 25 kHz
Data Rate 10 kbps 8 kbps 0.3 kbps
Spectral Efficiency 0.33 bps/Hz 0.33 bps/Hz 0.012 bps/Hz
Capacity 832 channels 1000 channels 600 channels
AMPS: Advanced Mobile Phone System (America and Australia)
ETACS: European Total Access Communications System
NTT: Nippon Telephone and Telegraph System
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4. Wireless Communications and Networking Ch1 - Page 4 of 8
Second Generation Digital Cellular Systems:
Region U.S. Europe Japan U.S.
Parameter IS-54 GSM PDC IS-95
Multiple Access TDMA/FDD TDMA/FDD TDMA/FDD CDMA/FDD
Modulation π/4 DQPSK GMSK π/4 DQPSK QPSK/OQPSK
Forward Channel 869-894 MHz 935-960 MHz 810-826 MHz 869-894 MHz
Reverse Channel 824-849 MHz 890-915 MHz 940-956 MHz 824-849 MHz
Channel Spacing 30 kHz 200 kHz 25 kHz 1,250 kHz
Data/Chip Rate 48.6 kbps 270.833 kbps 42 kbps 1.2288 Mcps
Speech Codec Rate 7.95 kbps 13.4 kbps 6.7 kbps 1.2/2.4/
4.8/9.6 kbps
IS (Interim Standard)-54: North-America TDMA Digital Cellular System
GSM: Groupe Special Mobile −→ Global System for Mobile
PDC: Personal Digital Cellular
IS-95: CDMA Cellular System
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5. Wireless Communications and Networking Ch1 - Page 5 of 8
Third Generation Wireless Communications Networks:
◦ support high rate and variable rate transmission
◦ provide voice, data, and low-rate video multimedia services
◦ use convolutional coding for voice and Turbo coding for data
◦ use wideband CDMA (WCDMA) or multi-carrier CDMA (MC-CDMA)
◦ operate in TDD or FDD
◦ fast power control and reverse link pilot signals
◦ synchronous or asynchronous transmission
◦ will be equipped with the infrastructure to support Personal Communications Systems
(PCS)
◦ The network infrastructure support will likely include
- public land mobile networks (PLMNs),
- Mobile Internet Protocol (Mobile IP),
- wireless asynchronous transfer mode (WATM) networks, and
- low earth orbit (LEO) satellite networks.
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6. Wireless Communications and Networking Ch1 - Page 6 of 8
3G Air Interface Options:
Air interface IMT class Technology Standard Name
CDMA IMT-DS direct spread UTRA-FDD WCDMA
CDMA IMT-MC multicarrier IS-95C/cdma2000 Multicarrier
CDMA IMT-TC time code UTRA-TDD TD-SCDMA
TDMA IMT-SC single carrier UWC-136 n.a.
Partnership Projects:
• Third-Gneration Partnership Project (3GPP)
- comprised primarily of those bodies that were responsible for GSM standards
(mainly Europe and Asia)
- concerned with UTRA-FDD and UTRA-TDD
- support GSM-MAP approach for network signaling
- support WCDMA air interface
• Third-Generation Partnership Project 2 (3GPP2)
- comprised primilarily of those bodies that were responsible for the IS-136 and
IS-95 standards (mainly US)
- concerned with cdma2000 and UWC-136
- support ANSI-41 approach for network signaling
- support multicarrier CDMA
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7. Wireless Communications and Networking Ch1 - Page 7 of 8
High-speed wireless data technologies as of early 2004:
Technologies Gener- Multiple Carrier Peak Data Modulation Data/Voice
ation Access Bandwidth Rate Support
GPRS 2.5G TDMA 0.2MHz 115kbps GMSK data
Designed as overlay on GSM / TDMA Networks
EDGE 2.5G TDMA 2.4Mbps 384kbps 8PSK/GMSK data
Designed as overlay on GSM / TDMA Networks
cdma2000 1x 3G CDMA 1.25Mbps 628kbps BPSK/QPSK data+voice
Rel. 0
IS-856 3G+ CDMA/ 1.25Mbps 2.4576Mbps QPSK/8PSK/ data
(1xEV-DO, TDMA 16QAM
HDR) Designed as high data rate extension to cdma2000
cdma2000 1x 3G+ CDMA 1.25Mbps 3.0912Mbps QPSK/8PSK data+voice
Rel. D 16QAM
(1xEV-DV) Designed as high data rate extension to cdma2000 1x with voice support
UMTS Rel. 5 3G CDMA 3.84MHz 1.96Mbps QPSK/16QAM data+voice
(HSDPA) Designed as high throughput, high peak data rate extension to UMTS Release 99
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8. Wireless Communications and Networking Ch1 - Page 8 of 8
1.3 What we will study in this course?
Focus: principles of wireless communications
- Characterization of the propagation channel (Chapter 2)
- Bandpass signaling techniques (Chapter 3)
- Diversity (Chapter 4)
- Fundamentals of cellular communications (Chapter 5)
- Multiple access techniques (Chapter 6)
- Mobility management (Chapter 7)
- Wireless/wireline interworking (Chapter 8)
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