Contents CDMA CDMA CDMA 2000 10 17 CBNU
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![Contents 개요 CDMA 순방향 채널 CDMA 역방향 채널 CDMA 시스템의 특성 2000 -10 -17 Contents 개요 CDMA 순방향 채널 CDMA 역방향 채널 CDMA 시스템의 특성 2000 -10 -17](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-2.jpg)
Contents 개요 CDMA 순방향 채널 CDMA 역방향 채널 CDMA 시스템의 특성 2000 -10 -17 CBNU 2
![개요 디지털 셀룰러 무선 접속 규격 w TDMA(Time Division Multiple Access) : IS-54 w 개요 디지털 셀룰러 무선 접속 규격 w TDMA(Time Division Multiple Access) : IS-54 w](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-3.jpg)
개요 디지털 셀룰러 무선 접속 규격 w TDMA(Time Division Multiple Access) : IS-54 w CDMA(Code Division Multiple Access) : IS-95 w AMPS 시스템과 동일 주파수대에서 호환 가능하도록 이중모드 지원 w Voice Activity에 의한 Traffic Channel에서 Variable data rate 지원 w Rate Set 1 : 1200, 2400, 4800, 9600 bps w Rate Set 2 : 1800, 3600, 7200, 14400 bps w Unbalance Channel Link Structure w Forward Link : Pilot, Sync, Paging, Traffic Channel w Reverse Link : Access, Traffic Channel w Forward 와 Reverse는 서로 다른 변조 및 확산 방식 사용 w Forward : Walsh Code에 의해 확산 w Reverse : Long Code에 의해 확산 w Vocoder w QCELP : 8 K, 13 K 지원 w EVRC : 8 K 지원 2000 -10 -17 CBNU 3
![개요 (2) Frequency Parameter w Forward Link : 869 ~ 894 MHz w Reverse 개요 (2) Frequency Parameter w Forward Link : 869 ~ 894 MHz w Reverse](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-4.jpg)
개요 (2) Frequency Parameter w Forward Link : 869 ~ 894 MHz w Reverse Link : 824 ~ 849 MHz w Channel Spacing : 30 KHz(DCN), 50 KHz(PCS) w Bandwidth : 1. 25 MHz w FA : 1. 25 MHz w Chip Rate : 1. 2288 Mcps 2000 -10 -17 CBNU 4
![개요 (3) Spread Processing w Forward Link w Convolution Coding(1/2), Block Interleaving, Walsh Code 개요 (3) Spread Processing w Forward Link w Convolution Coding(1/2), Block Interleaving, Walsh Code](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-5.jpg)
개요 (3) Spread Processing w Forward Link w Convolution Coding(1/2), Block Interleaving, Walsh Code Spreading, Short PN Code Spreading w Short PN Code : 기지국을 구별, Maximum Length(215 -1) w Pilot Channel 사용 : 이동국에 의해 coherent 검출 w Reverse Link w Convolution Coding(1/3), Block Interleaving, Walsh Modulation, Long PN Code Spreading w Walsh Modulation : 6개 부호와 된 심볼을 Walsh code로 대체 w Long PN Code : 사용자 구분을 위해 사용, Maximum Length(241 -1) 2000 -10 -17 CBNU 5
![개요 (4) Power Control w Open Loop Power Control w Forward Open Loop Power 개요 (4) Power Control w Open Loop Power Control w Forward Open Loop Power](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-6.jpg)
개요 (4) Power Control w Open Loop Power Control w Forward Open Loop Power Control w Reverse Open Loop Power Control w Slow Fading(Log-Normal) 보상 w Reverse Close Loop Power Control : w Fast Fading(Rayleigh fading) 보상 w 800 bps(1. 25 ms) 속도로 전력제어비트를 user data안에 puncturing하여 이 동국으로 전송 Muti-path fading을 위해 기지국과 이동국에 Rake 수신기 사용 w w 기지국 : 4개 이동국 : 3개 2000 -10 -17 CBNU 6
![CDMA 순방향채널 순방향 채널 구성 w 64개의 Walsh Code에 의해 Logical 하게 구분 w CDMA 순방향채널 순방향 채널 구성 w 64개의 Walsh Code에 의해 Logical 하게 구분 w](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-7.jpg)
CDMA 순방향채널 순방향 채널 구성 w 64개의 Walsh Code에 의해 Logical 하게 구분 w Pilot Channel : 1 개, Walsh Code 0사용 w Sync Channel : 1개, Walsh Code 32 사용 w Paging Channel : 1 ~ 7개, Walsh Code 1 ~ 7번 사용 w Traffic Channel : 1개의 Paging을 사용했을 경우 최대 61개 까지 사용 가 능 2000 -10 -17 CBNU 7
![CDMA 순방향채널 – Pilot Channel Transmitted Constantly Allows Mobile to Acquire the System w CDMA 순방향채널 – Pilot Channel Transmitted Constantly Allows Mobile to Acquire the System w](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-8.jpg)
CDMA 순방향채널 – Pilot Channel Transmitted Constantly Allows Mobile to Acquire the System w 코히런트 복조를 하기 위한 위상 기준 제공 Provides Mobile with Signal Strength Comparison w 핸드오프 결정 Has Unique PN Offset for each Cell or Sector w Short PN Code Length : 215=32768 Chip=512 PN Offset w 1 PN Offset = 64 Chip Approximately 20% of radiated power is in the pilot W 0 I PN 1. 2288 Mcps All 0's 2000 -10 -17 CBNU Q PN 8
![CDMA 순방향채널 – Sync Channel Used by Mobile to Synchronize with System Transmits sync CDMA 순방향채널 – Sync Channel Used by Mobile to Synchronize with System Transmits sync](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-9.jpg)
CDMA 순방향채널 – Sync Channel Used by Mobile to Synchronize with System Transmits sync Message with w Pilot PN Offset w System Time w Long PN Code w CAI Rev. Level w System ID w Network ID w Paging Channel Data Rate Tx at 1200 bps W 32 R = 1/2, K=9 1200 bps Convolutional Encoder and Repetition 2000 -10 -17 Block Interleaver 4800 sps CBNU I PN 1. 2288 Mcps Q PN 9
![CDMA 순방향채널 - Paging Channel Provides Mobile with: w System parameter Message w Neighbor CDMA 순방향채널 - Paging Channel Provides Mobile with: w System parameter Message w Neighbor](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-10.jpg)
CDMA 순방향채널 - Paging Channel Provides Mobile with: w System parameter Message w Neighbor List w Access Parameter list w CDMA Channel List Used by Base Station to: w Page Mobile w Transmit Overhead Information w Assign Mobile to Traffic Channel W 32 Tx at 9600 or 4800 BPS R = 1/2, K=9 9600 bps 4800 bps Convolutional Encoder and Repetition Paging Channel Address Mask 2000 -10 -17 Block Interleaver Long Code PN Generator 1. 2288 Mcps 19. 2 ksps 1. 2288 Mcps Decimator CBNU I PN 19. 2 ksps Q PN 10
![CDMA 순방향채널 - Traffic Channel Used to: w Pass voice, commands, and requests from CDMA 순방향채널 - Traffic Channel Used to: w Pass voice, commands, and requests from](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-11.jpg)
CDMA 순방향채널 - Traffic Channel Used to: w Pass voice, commands, and requests from the Base Station to the Mobile Tx up to 9600 bps on Rate set 1 and up to 14400 bps on Rate set 2 For Rate set 2 Power Control Bit Rate set 1 Rate set 2 9600 bps 14400 bps 4800 bps 7200 bps 2400 bps 3600 bps 1200 bps 1800 bps R = 1/2 Convolutional Encoder and Repetition User Address Mask(ESN) 2000 -10 -17 Block Interleaver 19. 2 ksps Wt 1. 2288 Mcps MUX Puncturing + I PN + + + 1. 2288 Mcps Long Decimator Code PN Generator CBNU 19. 2 ksps Decimator 4 800 Hz Q PN 11
![CDMA 순방향채널 Traffic Channel Modulation Parameter Data Rate(bps) User Data Rate 9600 4800 2400 CDMA 순방향채널 Traffic Channel Modulation Parameter Data Rate(bps) User Data Rate 9600 4800 2400](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-12.jpg)
CDMA 순방향채널 Traffic Channel Modulation Parameter Data Rate(bps) User Data Rate 9600 4800 2400 1200 Code Rate 1/2 1/2 사용자 데이터 반복 주기 1 2 4 8 코딩된 심볼 속도(sps) 19, 200 PN chip 수/코딩된 심볼 64 64 PN chip rate (Mcps) 1. 2288 PN chip 수 / 사용자데이터 비트 128 256 512 1024 2000 -10 -17 CBNU 12
![CDMA 순방향채널 - Channel Coding Convolutional Encoder ë Forward Link & Rate set 2 CDMA 순방향채널 - Channel Coding Convolutional Encoder ë Forward Link & Rate set 2](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-13.jpg)
CDMA 순방향채널 - Channel Coding Convolutional Encoder ë Forward Link & Rate set 2 Reverse Link ; R = 1/2, K = 9, g 0 = 753(8)=111101011(2) g 1 = 561(8)=101110001(2) ‘ 1’ : Connection ‘ 0’ : Disconnection ex) Forward link g 0 c 0 Data bits input Code Symbols Output g 1 2000 -10 -17 c 1 CBNU 13
![CDMA 순방향채널 - Symbol Repetition ë Repetition maintains constant symbol rate output Input Data CDMA 순방향채널 - Symbol Repetition ë Repetition maintains constant symbol rate output Input Data](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-14.jpg)
CDMA 순방향채널 - Symbol Repetition ë Repetition maintains constant symbol rate output Input Data Rate Repetition Rate Symbol Rate FL / RL Rate Set 1 9600 4800 2400 1200 No repetition Repeat 1 time (2 symbols) Repeat 3 times (4 symbols) Repeat 7 times (8 symbols) 19200 / 28800 Rate Set 2 14400 7200 3600 1800 No repetition Repeat 1 time (2 symbols) Repeat 3 times (4 symbols) Repeat 7 times (8 symbols) 28800 / 28800 2000 -10 -17 CBNU 14
![CDMA 순방향채널 - Block Interleaving ë The Process of permuting a sequence of symbol CDMA 순방향채널 - Block Interleaving ë The Process of permuting a sequence of symbol](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-15.jpg)
CDMA 순방향채널 - Block Interleaving ë The Process of permuting a sequence of symbol Data Input Data Output 1 13 25 37 49 2 14 26 38 50 3 15 27 39 51 4 16 28 40 52 5 17 29 41 53 6 18 30 42 54 7 19 31 43 55 8 20 32 44 56 9 21 33 45 57 10 22 34 46 58 11 23 35 47 59 12 24 36 48 60 w Changes sequence of data stream w Reduces loss sequential data w Improves ability to reconstruct original data w Burst Error를 Random Error로 변화 시키는 효과 2000 -10 -17 CBNU 15
![CDMA 순방향채널 - Pseudo-random Noise (PN) Two PN Codes w Short code (215) w CDMA 순방향채널 - Pseudo-random Noise (PN) Two PN Codes w Short code (215) w](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-16.jpg)
CDMA 순방향채널 - Pseudo-random Noise (PN) Two PN Codes w Short code (215) w Unique identifier for a cell or a sector w Repeats every 26. 67 msec w Consists of I and Q codes (different polynomials) w Long code (242 -1) w Unique identifier for : w Subscriber w Access channel (Reverse Link) w Paging channel (forward Link) w Performs spreading on reverse channels only w Repeats every 41. 4 days 2000 -10 -17 CBNU 16
![CDMA 순방향채널 - Short PN code 생성 PI Zero argument PQ Zero argument I CDMA 순방향채널 - Short PN code 생성 PI Zero argument PQ Zero argument I](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-17.jpg)
CDMA 순방향채널 - Short PN code 생성 PI Zero argument PQ Zero argument I 위상 시퀀스 PI(x)=x 15+ x 13+ x 9+ x 8+ x 7+ x 5+1 Q 위상 시퀀스 PQ(x)=x 15+ x 12+ x 11+ x 10+ x 6+ x 5+x 4+ x 3+1 Zero argument w 14개의 연속된 ‘ 0’이 나온 후에 하나의 ‘ 0’을 삽입(그러므로 길이는 32768 chip) w Short PN 시퀀스 Chip rate 1. 2288 Mcps, 주기는 32768/1228800=26. 666 ms 2000 -10 -17 CBNU 17
![CDMA 순방향채널 - Long PN code 생성 Long PN Code 발생기 w 42 bit CDMA 순방향채널 - Long PN code 생성 Long PN Code 발생기 w 42 bit](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-18.jpg)
CDMA 순방향채널 - Long PN code 생성 Long PN Code 발생기 w 42 bit mask와 42 bit 상태 백터의 모듈러-2 내적에 의해 생성 용도 : 데이터의 Scrambling 1 42 bit Long code Mask 2 3 4 5 6 7 8 9 10 39 40 41 42 Modula-2 Addition LSB MSB Long Code Long PN Code 생성 다항식 P(x)=x 42+x 35+x 33+x 31+x 27+x 26+x 25+x 22+x 21+x 19+x 18+x 17+x 16+x 10+x 7+x 6+x 5 +x 3 +x 2 +x 1 +1 2000 -10 -17 CBNU 18
![CDMA 순방향채널 – Long Code Mask Bit Traffic Channel w Public Mask : 이동국의 CDMA 순방향채널 – Long Code Mask Bit Traffic Channel w Public Mask : 이동국의](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-19.jpg)
CDMA 순방향채널 – Long Code Mask Bit Traffic Channel w Public Mask : 이동국의 기기번호(ESN: Electronics Serial Number) 기본 w ESN의 순서 뒤바꿔 ESN이 연속될 경우 발생된 PN코드의 상관 관계가 커지는 것을 방지 w 모든 호는 공용마스크로 시작하여 인증 받음. w Private Mask : 이동국의 식별번호(MIN: Mobile Identification Number) 기본 w 가입자 인증이 완료되면 사용됨. Long Code Mask Bit w Public Long Code 11000 치환된 ESN M 41 M 0 w Private Long Code 0 1 M 41 2000 -10 -17 M 0 CBNU 19
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![CDMA 순방향채널 - Walsh 직교 커버링 Walsh Codes w Consist of 64 codes each CDMA 순방향채널 - Walsh 직교 커버링 Walsh Codes w Consist of 64 codes each](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-22.jpg)
CDMA 순방향채널 - Walsh 직교 커버링 Walsh Codes w Consist of 64 codes each 64 bits long w Are orthogonal to each other w Provide each channel with a unique identifier w Pilot(W 0), Sync(W 32), Paging(W 1 ~ W 7), Traffic(W 2 ~W 31, W 33~ W 63) Orthogonal Codes w Two codes are orthogonal if the result of exclusive-OR-ing them Example: results in an equal number of 1's and 0's Creating Orthogonal Codes: 0011010011 01010 011001 2000 -10 -17 0 00 01 • Repeat code - Right - Below • Invert code(diagonally) CBNU 00 00 01 01 00 11 01 10 22
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![CDMA 역방향채널 – Access Channel Convolutional Encoder r=1/3, K=9 4800 bps 코드 심볼 14. CDMA 역방향채널 – Access Channel Convolutional Encoder r=1/3, K=9 4800 bps 코드 심볼 14.](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-25.jpg)
CDMA 역방향채널 – Access Channel Convolutional Encoder r=1/3, K=9 4800 bps 코드 심볼 14. 4 ksps 코드 심볼 symbol Repetition Block Interleaver 28. 8 ksps 코드 심볼 28. 8 ksps Walsh Cover 변조심볼 (Walsh Chip) 4. 8 ksps (307. 2 kcps) I 채널 파일럿 PN 1. 2288 Mcps I 1. 2288 Mcps cos(2 fct) 1/2 PN chip 지연 Q D Long Code PN Generator I(t) Baseband Filter S(t) Q(t) Baseband Filter sin(2 fct) Q 채널 파일럿 PN 1. 2288 Mcps Long Code Mask bit 2000 -10 -17 CBNU 25
![CDMA 역방향채널 - Traffic Channel 9600 bps 4800 bps 2400 bps 1200 bps Convolutional CDMA 역방향채널 - Traffic Channel 9600 bps 4800 bps 2400 bps 1200 bps Convolutional](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-26.jpg)
CDMA 역방향채널 - Traffic Channel 9600 bps 4800 bps 2400 bps 1200 bps Convolutional Encoder r=1/3, K=9 코드 심볼 ksps 28. 8 14. 4 7. 2 3. 6 symbol Repetition 코드 심볼 28. 8 ksps Block Interleaver I Long Code PN Generator 28. 8 ksps Walsh Cover 변조심볼 (Walsh Chip) I 채널 파일럿 PN 1. 2288 Mcps Data Burst Randomizer 1. 2288 Mcps 코드 심볼 4. 8 ksps (307. 2 kcps) cos(2 fct) 1/2 PN chip 지연 D I(t) Baseband Filter Q Q 채널 파일럿 PN 1. 2288 Mcps Q(t) Baseband Filter sin(2 fct) Long Code Mask bit 2000 -10 -17 CBNU 26 S(t)
![CDMA 역방향채널 - 변조파라미터 Parameters Data Rate 사용자 data rate 9600 4800 2400 1200 CDMA 역방향채널 - 변조파라미터 Parameters Data Rate 사용자 data rate 9600 4800 2400 1200](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-27.jpg)
CDMA 역방향채널 - 변조파라미터 Parameters Data Rate 사용자 data rate 9600 4800 2400 1200 Code rate 1/3 1/3 전송 듀티사이클(%) 100 50 25 12. 5 코딩된 심볼 속도(sps) 28, 800 Walsh 심볼당 비트 수 6 6 Walsh symbol rate 4800 Walsh chip rate(kcps) 307. 2 Walsh 심볼 길이(us) 208. 33 PN chip수 / 코드 심볼 42. 67 PN chip수/Walsh 심볼 256 256 PN chip수/Walsh chip 4 4 PN chip rate(Mcps) 1. 2288 2000 -10 -17 CBNU 27
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![CDMA 역방향채널 - 역방향링크에서 가변데이터율 전송 방법 20 ms=96변조심볼=16전력제어그룹 1. 25 ms=12비트=36코드심볼=6변조심볼=1 PCG 이전프레임 CDMA 역방향채널 - 역방향링크에서 가변데이터율 전송 방법 20 ms=96변조심볼=16전력제어그룹 1. 25 ms=12비트=36코드심볼=6변조심볼=1 PCG 이전프레임](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-30.jpg)
CDMA 역방향채널 - 역방향링크에서 가변데이터율 전송 방법 20 ms=96변조심볼=16전력제어그룹 1. 25 ms=12비트=36코드심볼=6변조심볼=1 PCG 이전프레임 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 이전프레임 12 13 14 15 9600 bps 4800 bps 2400 bps 1200 bps 14비트 PN열 = (b 0, b 1, …. b 13) = 001011100100 스크램블링에 사용된 PN비트 b b b b 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 PCG 14 2000 -10 -17 PCG 15 CBNU 30
![CDMA 시스템의 특성 여러 형태의 다이버시티 w 시간 다이버시티 w 인터리빙(burst error -> random CDMA 시스템의 특성 여러 형태의 다이버시티 w 시간 다이버시티 w 인터리빙(burst error -> random](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-31.jpg)
CDMA 시스템의 특성 여러 형태의 다이버시티 w 시간 다이버시티 w 인터리빙(burst error -> random error) w 오류정정부호화 (Encoding(convolution), Decoding(viterbi decoder)) w 주파수 다이버시티 w 신호에너지를 넓은 주파수대역으로 확산 시킴 w 공간 또는 경로 다이버시티 w 기지국 복수안테나 사용, w 레이크 수신기 구성, 소프트 핸드오프 구성(CDMA 시스템에서만 가능) 전력제어 w Open-loop Power Control w Estimate long-term fading, Slow Control w Adjust TX power so that TX power + RX power = -73 d. Bm(DCN), -76(PCS) w Closed-loop Power Control w Refine the estimate by Outer Loop control(800 bps control), Fast Control w BTS measures RX power every 1. 25 ms w BTS commands MS to adjust power in 1 d. B step w Forward Link Power Control w Can adjusts its transmit level based on Mobile’s reported error rate(Rate 1) or EIB(Rate 2) 2000 -10 -17 CBNU 31
![](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-32.jpg)
![](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-33.jpg)
![CDMA 시스템의 특성 - 핸드오프 Softer Handoff(Multi-Sector Handoff) w Can have up to 3 CDMA 시스템의 특성 - 핸드오프 Softer Handoff(Multi-Sector Handoff) w Can have up to 3](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-34.jpg)
CDMA 시스템의 특성 - 핸드오프 Softer Handoff(Multi-Sector Handoff) w Can have up to 3 or 6 sectors involved (same cell) w Voice data is combined at cell and passed as one frame to BSC w Make before break α BSC 보코더 (One voice frame) γ β BTS 채널 (combining & Decoding) 2000 -10 -17 CBNU 34
![CDMA 시스템의 특성 - 핸드오프 Soft Handoff(Multi-Cell Handoff) w Inter BTS, BSC, MSC w CDMA 시스템의 특성 - 핸드오프 Soft Handoff(Multi-Cell Handoff) w Inter BTS, BSC, MSC w](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-35.jpg)
CDMA 시스템의 특성 - 핸드오프 Soft Handoff(Multi-Cell Handoff) w Inter BTS, BSC, MSC w Can have up to 3 cells involved (same FA) w Each cell provides voice data to BSC w Voice data is selected at SVC to vocoder in BSC w Make before break Strength Cell A Cell B Soft Handoff Here BSC Select Best Voice Frame Threshold Level Mobile Assisted Hard Handoff Here Distance Vocoder FM Handoff Here 2000 -10 -17 CBNU 35
![CDMA 시스템의 특성 - 핸드오프 Hard Handoff w Inter Frequency Assignment w Inter Frame CDMA 시스템의 특성 - 핸드오프 Hard Handoff w Inter Frequency Assignment w Inter Frame](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-36.jpg)
CDMA 시스템의 특성 - 핸드오프 Hard Handoff w Inter Frequency Assignment w Inter Frame Offset w Break before make FA 2 FA 1 Cell B 2000 -10 -17 Cell A CBNU 36
![CDMA 시스템의 특성 - Capacity Estimates N= W/R Eb / Io 1 d 1 CDMA 시스템의 특성 - Capacity Estimates N= W/R Eb / Io 1 d 1](http://slidetodoc.com/presentation_image_h2/7820b7361d1251b746c27f0f0e36aa60/image-37.jpg)
CDMA 시스템의 특성 - Capacity Estimates N= W/R Eb / Io 1 d 1 1+f η g Where : N : Calls per Sector W : Spread Spectrum Bandwidth [1. 25 MHz] R : Data Rate [9. 6 Kbps / 14. 4 Kbps] Eb/I 0: Bit Energy / I 0 [7 d. B] (I 0 = Other User Interference Density) d : Voice Activity Gain [40%] f : Other Interference / Same Interference [0. 6] η : Loading Factor [0. 8] g : Reduction for Variable Power [0. 85] 27 Users per Sector for R=9. 6 Kbps 18 Users per Sector for R=14. 4 Kbps 13. 5 Times than AMPS 5 Times than TDMA 2000 -10 -17 CBNU 37
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