CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA)...
-
date post
22-Dec-2015 -
Category
Documents
-
view
214 -
download
1
Transcript of CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA)...
![Page 1: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/1.jpg)
CS 218 Fall 2003October 23, 2003
• Cellular Wireless Networks– AMPS (Analog)– D-AMPS (TDMA)– GSM– CDMA
Reference: Tanenbaum Chpt 2 (pg 153-169)
![Page 2: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/2.jpg)
Cellular Wireless Network Evolution
• First Generation: Analog– AMPS: Advance Mobile Phone Systems– Residential cordless phones
• Second Generation: Digital– IS-54: North American Standard - TDMA– IS-95: CDMA (Qualcomm)– GSM: Pan-European Digital Cellular– DECT: Digital European Cordless Telephone
![Page 3: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/3.jpg)
Cellular Evolution (cont)• Third Generation: T/CDMA– combines the functions of: cellular, cordless, wireless
LANs, paging etc.
– supports multimedia services (data, voice, video, image)
– a progression of integrated, high performance systems:
(a) GPRS (for GSM)
(b) EDGE (for GSM)
(c) 1xRTT (for CDMA)
(d) UMTS
![Page 4: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/4.jpg)
![Page 5: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/5.jpg)
![Page 6: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/6.jpg)
![Page 7: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/7.jpg)
Digital Cellular Systems World-wide
GSMD-AMPSJapan DigitalPCS 1900DCS 1800CDMA
![Page 8: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/8.jpg)
![Page 9: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/9.jpg)
Cellular Concept• Geographical separation• Capacity (frequency) reuse• Backbone connectivity
BS BSBS
BSBSBS
Backbone Network
![Page 10: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/10.jpg)
Characteristics of Radio Medium
Path Loss– Attenuation increases with respect to frequency and
distance• Free space loss = square of distance
• Indoor mobile radio = fourth power of distance
Transmitter
R1 Distance
10 100 1000
Pow
er40 dB per decade
20 dB per decade
Distance
![Page 11: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/11.jpg)
Characteristics of Radio Medium (cont’d)
• Fading– Multipath fading– Shadowing
• Delay spread– Intersymbol interference
• Interference– Across channels
Transmitter
Object
Receiver
Pow
er d
B
Deep fade - 40 dB
![Page 12: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/12.jpg)
Invented by Bell Labs; installed In US in 1982; in Europe as TACS
![Page 13: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/13.jpg)
AMPS (Advance Mobile Phone System):
In each cell, 57 channels each for A-side and B -side carrier
respectively; about 800 channels total (across the entire AMPS system)
B
A
ED
C
F
G
B
A
ED
C
F
G
B
A
ED
C
F
G Frequency Reuse: Frequencies are not reused in a group of 7 adjacent cells
FDMA (Frequency Div Multiple Access): one frequencyper user channel
![Page 14: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/14.jpg)
Advanced Mobile Phone System
(a) Frequencies are not reused in adjacent cells.
(b) To add more users, smaller cells can be used.
![Page 15: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/15.jpg)
Channel CategoriesThe channels are divided into four categories:
• Control (base to mobile) to manage the system
• Paging (base to mobile) to alert users to calls for them
• Access (bidirectional) for call setup and channel assignment
• Data (bidirectional) for voice, fax, or data
![Page 16: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/16.jpg)
Handoff• Handoff: Transfer of a mobile from one cell to another
• Each base station constantly monitors the received power from each mobile.
• When power drops below given threshold, base station asks neighbor station (with stronger received power) to pick up the mobile, on a new channel.
• In APMS the handoff process takes about 300 msec.
• Hard handoff: user must switch from one frequency to another (noticeable disruption)
• Soft Handoff (available only with CDMA): no change in frequency.
![Page 17: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/17.jpg)
To register and make a phone call
• When phone is switched on , it scans a preprogrammed list of 21 control channels, to find the most powerful signal.
• It transmits its ID number on it to the MSC – which informs the home MSC (registration is done every 15 min)
• To make a call, user transmits dest Ph # on random access channel; MSC will assign a data channel
• At the same time MSC pages the destination cell for the other party (idle phone listens on all page channels)
![Page 18: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/18.jpg)
(Freq DivisionDuplex)
![Page 19: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/19.jpg)
![Page 20: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/20.jpg)
![Page 21: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/21.jpg)
Digital Cellular: IS-54 TDMA System
• Second generation: digital (as opposed to analog as in AMPS)• Same frequency as AMPS• Each 30 kHz RF channel is used at a rate of 48.6 kbps
– 6 TDM slots/RF band (2 slots per user)– 8 kbps voice coding– 16.2 kbps TDM digital channel (3 channels fit in 30kHz)
• 4 cell frequency reuse (instead of 7 as in AMPS)• Capacity increase per cell per carrier
– 3 x 416 / 4 = 312 (instead of 57 in AMPS)– Additional factor of two with speech activity detection.
![Page 22: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/22.jpg)
![Page 23: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/23.jpg)
![Page 24: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/24.jpg)
![Page 25: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/25.jpg)
![Page 26: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/26.jpg)
![Page 27: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/27.jpg)
IS-54 slot and frame structure
BASE TO MOBILE
SLOT 1 SLOT 2 SLOT 3 SLOT 4 SLOT 5 SLOT 6
Frame1944 bits in 40 ms( 48600 b/s)
G6
R6
DATA16
SYNC28
DATA122
SACCH12
DVCC 12
DATA122
MOBILE TO BASE
DATA130
DATA130
DVCC 12
SACCH 12
SYNC28
RSVD 12
G:GUARD TIME R:RAMP TIMEDVCC: DIGITAL VERIFFICATION COLOR CODERSVD: RESERVE FOR FUTURE USE
![Page 28: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/28.jpg)
![Page 29: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/29.jpg)
GSM (Group Speciale Mobile)
Pan European Cellular StandardSecond Generation: DigitalFrequency Division Duplex (890-915 MHz Upstream; 935-960 MHz Downstream)125 frequency carriers
Carrier spacing: 200 Khz8 channels per carrier (Narrowband Time Division)
Speech coder: linear predictive coding (Source rate = 13 Kbps)
Modulation: phase shift keying (Gaussian minimum shift keying)
Slow frequency hopping to overcome multipath fading
![Page 30: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/30.jpg)
![Page 31: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/31.jpg)
![Page 32: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/32.jpg)
![Page 33: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/33.jpg)
![Page 34: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/34.jpg)
![Page 35: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/35.jpg)
![Page 36: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/36.jpg)
![Page 37: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/37.jpg)
![Page 38: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/38.jpg)
![Page 39: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/39.jpg)
![Page 40: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/40.jpg)
![Page 41: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/41.jpg)
![Page 42: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/42.jpg)
BCCH: Broadcast Control Channel point-to-multipoint unidirectional control
channel broadcasting system information to MS
CCCH: Common Control Channelup-link: RACH (Random
Access CHannel)
down-link: PCH (Paging Channel)
AGCH (Access Grant CHannel)
DCCH: Dedicated Control CHannel point-to-point bidirectional control
channel SACCH (Slow Associated Control CHannel) FACCH (Fast Associated Control CHannel) SDCCH (Stand Alone Dedicated Control
CHannel)
GSM Signalling channels
![Page 43: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/43.jpg)
CDMA (Code Division Multiple Access): IS-95QUALCOMM, San Diego
• Based on DS spread spectrum
• Two frequency bands (1.23 Mhz), one for forward channel (cell-site to subscriber) and one for reverse channel (sub to cell-site)
• CDMA allows reuse of same spectrum over all cells. Net capacity improvement:
– 4 to 6 over digital TDMA (eg. GSM)– 20 over analog FM/FDMA (AMPS)
![Page 44: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/44.jpg)
Access techniques for mobile communications
P - PowerT - TimeF - Frequency
P
T
P
T
F
P
T
F
FDMA (TACS)
TDMA (GSM, DECT)
CDMA (UMTS)
F
ATDMA (UMTS)
![Page 45: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/45.jpg)
CDMA (Code Division Multiple Access)
• unique “code” assigned to each user; i.e., code set partitioning
• all users share same frequency, but each user has own “chipping” sequence (i.e., code) to encode data
• Note: chipping rate >> data rate (eg, 64 chips per data bit)
• encoded signal = (original data bit) X (chipping sequence)
• decoding: inner-product of encoded signal and chipping sequence
• allows multiple users to “coexist” and transmit simultaneously with minimal interference (if codes are “orthogonal”)
![Page 46: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/46.jpg)
CDMA Encode/Decode
![Page 47: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/47.jpg)
CDMA: two-sender interference
![Page 48: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/48.jpg)
CDMA (cont’d)
• One of 64 PS (Pseudo Random) codes assigned to subscriber at call set up time
• RAKE receiver (to overcome multi path-fading)• Pilot tone inserted in forward link for:
– power control
– coherent reference
• Speech activity detection • Voice compression to 8 kbps (16 kbps with FEC)
![Page 49: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/49.jpg)
![Page 50: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/50.jpg)
![Page 51: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/51.jpg)
![Page 52: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/52.jpg)
![Page 53: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/53.jpg)
![Page 54: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/54.jpg)
![Page 55: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/55.jpg)
![Page 56: CS 218 Fall 2003 October 23, 2003 Cellular Wireless Networks –AMPS (Analog) –D-AMPS (TDMA) –GSM –CDMA Reference: Tanenbaum Chpt 2 (pg 153-169)](https://reader038.fdocument.pub/reader038/viewer/2022110207/56649d7d5503460f94a5feb8/html5/thumbnails/56.jpg)