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CDMA Seminar

CDMA Seminar. Presenter : Yang Lianghua Contact : Tel : 010-65641733 (W) Email: a1816c@email.mot.com; lhyang@sc.mcel.mot.com 5/5/99. Content. History of cellular communication (The first, second, third generation)

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CDMA Seminar

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  1. CDMA Seminar Presenter : Yang Lianghua Contact : Tel : 010-65641733 (W) Email: a1816c@email.mot.com; lhyang@sc.mcel.mot.com 5/5/99

  2. Content • History of cellular communication (The first, second, third generation) • Comparison among all the multi-address (FDMA TDMA CDMA) • The theory of Spread communication and CDMA • The structure of CdmaOne BSS system (IS-95 system) • The Candidates of Third Generation mobile communication system (Cdma2000, Multi-Code & Multi-Band , WCDMA, WTD-CDMA ) • The structure of Cdma2000 system

  3. History • The First Generation Cellular System • AMPS, TACS, UMTS . . . • The Second Generation Cellular System • GSM, DAMPS, TDMA(IS-136), PDC, CDMA ( IS-95A) . . . • The Second & Half Generation Cellular System • CdmaOne ( IS-95B), GPRS . . . • The Third Generation Cellular System • Cdma2000, WCDMA, WTD-CDMA, Multi-Code & Multi-Band System

  4. Comparison • Human resource for wireless communication • Frequency, Time, Code, Space . . . • Frequency resource and theory of FDMA • Frequency assign (ITU and different country) • Analog System and FDMA • Voice band • Transmission frequent band

  5. Comparison • Multi-Address Frequency . . . Time 0

  6. Comparison • Periodic Time and TDMA • discontinuous transmission Time timeslot

  7. Comparison • Multi-Address Frequency . . . Time 0

  8. Comparison • Multi-Address of CDMA. Frequency Code Time

  9. Spread Communication • Information data modulated by high rate sequence • Narrow band spreading to wide band • Three ways to spread data band. • Frequency Hopping • Time Hopping • Direct sequence spread

  10. Spread Communication • Theory of Spread Communication • Frequency Amplification Amplification GWAN GWAN Frequency Frequency Data Band Spreading Band

  11. Spread Communication • Time sequence Information data spread sequence spreaded data

  12. CDMA • Orthogonal Sequences & their relativity • Self-relation • Correlation 1 • Walsh, m sequence ( Short PN), M sequence (Long PN), Gold . . .

  13. CDMA • Forward Logic Channel ( Identify Path ) • Walsh • Short PN • PN offset (BS ID) • Spreading sequence • Long PN • Long Code Mask (subscriber ID)

  14. IS-95A System • Forward Logic Channel ( 64 Orthogonal Walsh )

  15. IS-95A System • W(0) Pilot Channel • W(32) Sync Channel • W(1)~W(7) Paging Channel • W(8)~W(31) & W(33)~W(63) Traffic Channel • Sub-Channel for power control • Reverse Link Channel • Access Channel • Traffic Channel

  16. IS-95A System • Addressed by Long Code Mask

  17. IS-95A System • Long Code Mask • Forward paging long code mask • Forward traffic long code mask

  18. IS-95A System • Long Code Mask • Reverse access long code mask • Reverse traffic long code mask ( public as following, Private as encryption algorithm )

  19. IS-95A System • Forward Channel Structure • Pilot Channel

  20. IS-95A System • Sync Channel Structure

  21. IS-95A System • Paging Channel Structure

  22. IS-95A System • Traffic Channel Structure

  23. IS-95A System • Reverse Channel Structure • Access Channel

  24. IS-95A System • Traffic Channel Structure

  25. IS-95A System • The characters • Orthogonal 64 Walsh Code

  26. IS-95A System • Short PN • Long PN

  27. IS-95A System • Variable rate power control (VAD & Power Control) • Forward 9600bps Eb/2 4800bps Eb/4 2400bps Eb/8 1200bps Eb/16

  28. IS-95A System • Reverse ( Data burst)

  29. IS-95A System • Power Control • Revese power control • open loop Estimated by MS (Power of Pilot) • Close loop correction by MS and BS

  30. IS-95A System • Close loop correction by MS and BS

  31. IS-95A System • Close loop correction by MS and BS

  32. IS-95A System • Forward power control • open loop Estimated by BS ( the S/N or Power of mobile)

  33. IS-95A System • Long Code Encryption (Private long code encryption, Data scrambling )

  34. IS-95A System • Synchronize in CDMA BTS system

  35. IS-95A System • Frame Structure in CDMA BTS System

  36. IS-95A System • Primary and Signaling Traffic

  37. IS-95A System • Secondary Traffic

  38. IS-95A System • Handoff in IS-95 System • Hard Handoff (inter frequency & Frame) • Soft Handoff • Softer (intra BTS or inter sector) • soft (inter BTS)

  39. IS-95A System • Pilot in Soft handoff

  40. IS-95A System • Paras in Soft handoff • T_ADD • T_ DROP • T_TDROP

  41. IS-95A System • Example of Soft handoff

  42. IS-95A System • Pilot Strength Measurement in Soft handoff

  43. IS-95A System • System Capacity in CDMA • band: 10M • Three sectors in one BTS • 20 physical Channel • Coverage : 5 KM • One Frequency Band: 1.25M • System Capacity in GSM • band: 10M • Three sectors in one BTS • Coverage : 5 KM • Reuse Method 4*3 • One Frequency Band: 200K

  44. CdmaOne System OMCR MM CBSC BTS XC MSC MSC BSS IS-634A (A+) Abis IS-41D Um

  45. CdmaOne System • BTS system

  46. CdmaOne System

  47. CdmaOne System • CBSC system

  48. CdmaOne System • MM system

  49. CdmaOne System • MM Hardware

  50. CdmaOne System • XC system

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