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CDMA Theory Module

CDMA Theory Module. Unit 1 －－ CDMA Overview Unit 2 －－ CDMA Basic Principle Unit 3 －－ CDMA Channel Structure and Modulation Unit 4 －－ CDMA Key Technology. CDMA Theory Unit 1. CDMA Overview. Main Content.

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CDMA Theory Module

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  1. CDMA Theory Module Unit 1－－ CDMA Overview Unit 2－－ CDMA Basic Principle Unit 3－－ CDMA Channel Structure and Modulation Unit 4－－ CDMA Key Technology

  2. CDMA Theory Unit 1 CDMA Overview

  3. Main Content • The history of mobile communication • CDMA evolution path • The advantage of CDMA • CDMA spectrum usage • Role of ZTE in CDMA

  4. Evolution of Mobile Communications System AMPS: Advanced Mobile Phone System TACS: Total Access Communication System GPRS: General Packet Radio Services

  5. Mobile Communication Standards

  6. CDMA Status in The World • At present, CDMA commercial networks are established in about 50 countries or area, almost 20% of all users in the world.

  7. Advantages of CDMA(1) High privacy,hard to wiretapping Each user is below the noise deeply Spread signal Information signal Demodulated signal TX RX Spread code Spread code

  8. Advantages of CDMA(2) Good voice quality, uses 8k QCELP, 13K QCELP,8k EVRC, voice coding - the best coding method in the world. Voice quality (MOS) 13k GSM 13k QCELP CDMA 64k PCM 8k QCELP CDMA 8kEVRC CDMA

  9. AMPS, D-AMPS, N-AMPS 2 1 3 1 Users 3 7 1 6 4 5 30 30 10 kHz Typical Frequency Reuse N=7 GSM 2 1 8 Users 3 4 200 kHz Typical Frequency Reuse N=4 1 CDMA 1 1 1 1 1 1 1 20 Users 1 1 1 1 1 1 1250 kHz Typical Frequency Reuse N=1 Advantages of CDMA (3) Frequency reuse factor is 1; network design and expanding become much easier

  10. Advantages of CDMA Use soft handoff, decrease drop-call rate • CDMA System ”make before break”---- soft handoff • Other systems: “make after break” --------hard handoff

  11. Advantages of CDMA(5) Perfect Power Control and voice activation make the MS Power low, healthy for body—green mobile phone. Mean Power Max Power GSM: 125mW 2W CDMA: 2mW 200mW

  12. Advantages of CDMA(6) large coverage almost 2 times than GSM, save money for operator Example:cover 1000 km2： GSM need 200 BTS ，CDMA only need 50 BTS Attention: exact result need “Link Budget ”

  13. Advantages of CDMA(7) FDMA Power Frequency Time TDMA Power Frequency Time CDMA Power Frequency Time High spectrum capacity，8--10 times than AMPS,4—6 times than GSM FDMA---Different user use different frequency TACS、AMPS TDMA---Different user use different time slot of one frequency GSM、DAMPS CDMA---Different user use same frequency at the same time,but with different spreading code

  14. Advantages of CDMA(8) High speed packet switching structure, smooth migration to 3G ! the operator’s benefit is protected at the most ! 95A  95B • Software update • Replace MS to get new service Almost free 95B  1X • Add 1X channel board • Software update • Replace MS to get new service inexpensive 1X  1XEV • Add 1XEV channel board • Software update • Replace MS to get new service inexpensive Technical Scheme： Economic Scheme：

  15. CDMA 800 MHz Cellular Spectrum Usage Channel Numbers 1 1 991 333 334 666 667 716 717 799 991 333 334 666 667 716 717 799 1023 1023 A” A” A B A’ B’ other uses A B A’ B’ 1 10 10 1.5 2.5 1 10 10 1.5 2.5 824 MHz 849 MHz 869 MHz 894 MHz Reverse link (i.e., mobile transmits) Forward link (i.e., cell site transmits) Possible CDMA Center Freq. Assignments ~300 kHz. “guard bands” possibly required if adjacent-frequency signals are non-CDMA (AMPS, TDMA, ESMR, etc.) • All CDMA RF carriers are 1.25 MHz. Wide • Between CDMA carriers, no guard band

  16. CDMA Frequency ChannelAssignment at 800 MHz Cellular 1023 333 666 715 716 799 991 334 667 1 A” A Band B Band A’ B’ Channel Numbers 736 1019 37 78 119 160 201 242 283 384 425 466 507 548 589 630 691 777 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 9 9 8 * ** * *Requires frequency coordination with non-cellular interferers **Requires frequency coordination with A-band carrier CDMA A-Band Carriers CDMA B-Band Carriers A Band Primary Channel 283 A Band Secondary Channel 691 B Band Primary Channel 384 B Band Secondary Channel 777 Channel number? Up link: 825.00MHz+0.03MHz*N Down link: 870.00MHz+0.03MHz*N Center frequency

  17. ZTE’s Activities in CDMA • In 1995, CDMA mobile telecommunication project was started • In November, 1999, ZTE signed the “Agreement on CDMA R&D” with Qualcomm • In August, 2000, the first field trial was set up. • In September, 2000， ZTE presented the first CDMA handset with UIM (User Identification Module) in the world. • In January, 2001, the first cdma2000-1x call was passed through in lab • In March, 2001, ZTE cdma2000-1x realized the integrated transmission of voice, data & image.The data rate reach up to 153.6Kbps. • In 2003, ZTE first EV-DO all-IP trial network was set up.

  18. PSTN/PLMN MSC/VLR HLR/AUC Abis E1 BTS（IS-95） Um IS95 SC BSC（IS-95） Abis BTS（IS-95） WIN IP HA Um IS2000 Abis BSC/ PCF (1X) OMC E1 Internet E1 STM-1 2G/3G Terminals BTS（1X） Ethernet Router Router IP Abis Ethernet BSC/ PCF (1X) PDSN/FA E1 STM-1 AAA BTS（1X） Server ZTE－A Famous CDMA Brand

  19. Network Optimization Simulation ZTE Supply All Service Network Simulation Wireless Network Optimization Network Planning Maintenance Optimization

  20. ZTE Supply All Products

  21. The End!

  22. CDMA Theory Unit 2 CDMA Basic Principle

  23. Main Content • Definitions of CDMA and How to realize • Spread spectrum modulation • Spreading codes used in CDMA • Vocoding in CDMA

  24. Multiple Access Multiple Access: Simultaneous private use of a transmission medium by multiple, independent users. Since the beginning of telephony and radio, system operators have tried to squeeze the maximum amount of traffic over each circuit. Transmission Medium Each pair of users enjoys a dedicated, private circuit through the transmission medium, unaware that the other users exist. • Types of Media -- Examples: • Twisted pair - copper • Coaxial cable • Fiber optic cable • Air interface (radio signals) • Advantages of Multiple Access • Increased capacity: serve more users • Reduced capital requirements since fewer media can carry the traffic • Decreased per-user expense • Easier to manage and administer

  25. Channels Channel: An individually-assigned, dedicated pathway through a transmission medium for one user’s information. FDMA The transmission medium is a resource that can be subdivided into individual channels according to the technology used. Power Frequency Time TDMA Power Frequency Time CDMA Power Frequency Time • FDMA Frequency Division Multiple Access • Each user on a different frequency • A channel is a frequency • TDMA Time Division Multiple Access • Each user on a different window period in time (“time slot”) • A channel is a specific time slot on a specific frequency • CDMA Code Division Multiple Access • A channel is a unique code pattern • Each user uses the same frequency all the time, but mixed with different distinguishing code patterns

  26. Defining Our Terms CDMA CHANNEL CDMA Reverse Channel 1.25 MHz CDMA Forward Channel 1.25 MHz 45 or 80 MHz • CDMA Channel or CDMA Carrier or CDMA Frequency • Duplex channel made of two 1.25 MHz-wide bands of electromagnetic spectrum, one for Base Station to Mobile Station communication (called the FORWARD LINK or the DOWNLINK) and another for Mobile Station to Base Station communication (called the REVERSE LINK or the UPLINK) • In 800 Cellular these two simplex 1.25 MHz bands are 45 MHz apart • In 1900 MHz PCS they are 80 MHz apart • CDMA Forward Channel • 1.25 MHz Forward Link • CDMA Reverse Channel • 1.25 MHz Reverse Link • CDMA Code Channel • Each individual stream of 0’s and 1’s contained in either the CDMA Forward Channel or in the CDMA Reverse Channel • Code Channels are characterized (made unique) by mathematical codes • Code channels in the forward link: Pilot, Sync, Paging and Forward Traffic channels • Code channels in the reverse link: Access and Reverse Traffic channels

  27. Main Content • Definitions of CDMA and How to realize • Spread spectrum modulation • Spreading codes used in CDMA • Vocoding in CDMA

  28. ORIGINATING SITE DESTINATION Spread Data Stream Input Data Recovered Data Spreading Sequence Spreading Sequence What is Spread Spectrum Definition:Spread spectrum technique ,employ a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth. • Sender combines data with a fast spreading sequence, transmits spread data stream • Receiver intercepts the stream, uses same spreading sequence to extract original data

  29. Spread Spectrum Principles SHANON Formula C=B*log2(1+S/N) Where, C is capacity of channel, b/s B is signal bandwidth, Hz S is average power for signal, W N is average power for noise, W It is the basic principle and theory for spread spectrum communications.

  30. Direct Sequence CDMA Time Frequency User 1 + Code 1 = Composite How DSSS Spectrum Change

  31. CDMA Is a Spread-Spectrum System TRADITIONAL COMMUNICATIONS SYSTEM Spread Spectrum Narrowband Signal Slow Information Sent Slow Information Recovered TX RX SPREAD-SPECTRUM SYSTEM Wideband Signal Slow Information Sent Slow Information Recovered TX RX Fast Spreading Sequence Fast Spreading Sequence Spread Spectrum Payoff:Processing Gain • Traditional technologies try to squeeze the signal into the minimum required bandwidth • Direct-Sequence Spread spectrum systems mix their input data with a fast spreading sequence and transmit a wideband signal • The spreading sequence is independently regenerated at the receiver and mixed with the incoming wideband signal to recover the original data

  32. Spread Spectrum Principles Power is “Spread” Over a Larger Bandwidth 30 KHz 1.25 MHz MATH HAMMER MATH HAMMER

  33. Spread Spectrum Principles Many code channels are individually “spread” and then added together to create a “composite signal”

  34. Anything We Can Do, We Can Undo ORIGINATING SITE DESTINATION Spread Data Stream (Base Band + Spreading Sequence) Recovered Data (Base Band) Input Data (Base Band) Spreading Sequence Spreading Sequence • Any data bit stream can be combined with a spreading sequence • The resulting signal can be de-spread and the data stream recovered if the original spreading sequence is available and properly synchronized • After de-spreading, the original data stream is recovered intact

  35. CDMA Spreading PrincipleUsing Multiple Codes ORIGINATING SITE DESTINATION Spread-Spectrum Chip Streams X+A X+A+B X+A+B+C X+A+B X+A Input Data X Recovered Data X Spreading Sequence A Spreading Sequence B Spreading Sequence C Spreading Sequence C Spreading Sequence B Spreading Sequence A • Multiple spreading sequences can be applied in succession and then reapplied in opposite order to recover the original data stream. • The spreading sequences can have different desired properties. • All spreading sequences originally used must be available in proper synchronization at the recovering destination.

  36. “Shipping and Receiving” via CDMA Shipping Receiving FedEx FedEx Mailer Mailer Data Data • Whether in shipping and receiving or in CDMA, packaging is extremely important! • Cargo is placed inside “nested” containers for protection and to allow addressing. • The shipper packs in a certain order, and the receiver unpacks in the reverse order. • CDMA “containers” are spreading codes.

  37. Main Content • Definitions of CDMA and How to realize • Spread spectrum modulation • Spreading codes used in CDMA • Vocoding in CDMA

  38. Spreading code chip speed：1.2288Mc/s； Spreading codes used： Forward link—Walsh code & Short PN Reverse link—Long PN Spreading Codes in CDMA Spreading codes selection is the key of spread Spectrum modulation!

  39. Walsh Code Definition H H 0 0 0 0 n n = H 0 0 0 1 0 1 2n ___ 0 H H 0 1 0 0 1 1 n n 0 1 1 0 • The Walsh function is named after Walsh, the mathematician who proved it an orthogonal function in 1923. It is expressed as Walsh (n,t), n for the serial number. The CDMA system of IS-95 is differentiated with the Walsh function. • Walsh code is an orthogonal square matrix. It is just composed of +1(0) and –1(1). H4 H2 H1

  40. Walsh Codes WALSH CODES # ---------------------------------- 64-Chip Sequence ------------------------------------------ 0 0000000000000000000000000000000000000000000000000000000000000000 1 0101010101010101010101010101010101010101010101010101010101010101 2 0011001100110011001100110011001100110011001100110011001100110011 3 0110011001100110011001100110011001100110011001100110011001100110 4 0000111100001111000011110000111100001111000011110000111100001111 5 0101101001011010010110100101101001011010010110100101101001011010 6 0011110000111100001111000011110000111100001111000011110000111100 7 0110100101101001011010010110100101101001011010010110100101101001 8 0000000011111111000000001111111100000000111111110000000011111111 9 0101010110101010010101011010101001010101101010100101010110101010 10 0011001111001100001100111100110000110011110011000011001111001100 11 0110011010011001011001101001100101100110100110010110011010011001 12 0000111111110000000011111111000000001111111100000000111111110000 13 0101101010100101010110101010010101011010101001010101101010100101 14 0011110011000011001111001100001100111100110000110011110011000011 15 0110100110010110011010011001011001101001100101100110100110010110 16 0000000000000000111111111111111100000000000000001111111111111111 17 0101010101010101101010101010101001010101010101011010101010101010 18 0011001100110011110011001100110000110011001100111100110011001100 19 0110011001100110100110011001100101100110011001101001100110011001 20 0000111100001111111100001111000000001111000011111111000011110000 21 0101101001011010101001011010010101011010010110101010010110100101 22 0011110000111100110000111100001100111100001111001100001111000011 23 0110100101101001100101101001011001101001011010011001011010010110 24 0000000011111111111111110000000000000000111111111111111100000000 25 0101010110101010101010100101010101010101101010101010101001010101 26 0011001111001100110011000011001100110011110011001100110000110011 27 0110011010011001100110010110011001100110100110011001100101100110 28 0000111111110000111100000000111100001111111100001111000000001111 29 0101101010100101101001010101101001011010101001011010010101011010 30 0011110011000011110000110011110000111100110000111100001100111100 31 0110100110010110100101100110100101101001100101101001011001101001 32 0000000000000000000000000000000011111111111111111111111111111111 33 0101010101010101010101010101010110101010101010101010101010101010 34 0011001100110011001100110011001111001100110011001100110011001100 35 0110011001100110011001100110011010011001100110011001100110011001 36 0000111100001111000011110000111111110000111100001111000011110000 37 0101101001011010010110100101101010100101101001011010010110100101 38 0011110000111100001111000011110011000011110000111100001111000011 39 0110100101101001011010010110100110010110100101101001011010010110 40 0000000011111111000000001111111111111111000000001111111100000000 41 0101010110101010010101011010101010101010010101011010101001010101 42 0011001111001100001100111100110011001100001100111100110000110011 43 0110011010011001011001101001100110011001011001101001100101100110 44 0000111111110000000011111111000011110000000011111111000000001111 45 0101101010100101010110101010010110100101010110101010010101011010 46 0011110011000011001111001100001111000011001111001100001100111100 47 0110100110010110011010011001011010010110011010011001011001101001 48 0000000000000000111111111111111111111111111111110000000000000000 49 0101010101010101101010101010101010101010101010100101010101010101 50 0011001100110011110011001100110011001100110011000011001100110011 51 0110011001100110100110011001100110011001100110010110011001100110 52 0000111100001111111100001111000011110000111100000000111100001111 53 0101101001011010101001011010010110100101101001010101101001011010 54 0011110000111100110000111100001111000011110000110011110000111100 55 0110100101101001100101101001011010010110100101100110100101101001 56 0000000011111111111111110000000011111111000000000000000011111111 57 0101010110101010101010100101010110101010010101010101010110101010 58 0011001111001100110011000011001111001100001100110011001111001100 59 0110011010011001100110010110011010011001011001100110011010011001 60 0000111111110000111100000000111111110000000011110000111111110000 61 0101101010100101101001010101101010100101010110100101101010100101 62 0011110011000011110000110011110011000011001111000011110011000011 63 0110100110010110100101100110100110010110011010010110100110010110 EXAMPLE: Correlation of Walsh Code #23 with Walsh Code #59 #23 0110100101101001100101101001011001101001011010011001011010010110 #59 0110011010011001100110010110011010011001011001100110011010011001 XOR 0000111111110000000011111111000011110000000011111111000000001111 Correlation Results: 32 1’s, 32 0’s: Orthogonal!! • 64 Sequences, each 64 chips long • A chip is a binary digit (0 or 1) • Each Walsh Code is Orthogonal to all other Walsh Codes • This means that it is possible to recognize and therefore extract a particular Walsh code from a mixture of other Walsh codes which are “filtered out” in the process • Two same-length binary strings are orthogonal if the result of XORing them has the same number of 0s as 1s

  41. Walsh Code Table 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 6 6 6 6 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 2 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 3 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 4 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 5 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 6 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 7 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 8 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 9 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 10 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 11 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 12 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 13 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 14 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 15 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 17 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 18 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 19 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 20 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 21 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 22 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 23 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 24 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 25 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 26 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 27 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 28 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 29 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 30 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 31 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 32 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 33 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 34 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 35 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 36 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 37 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 38 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 39 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 40 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 41 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 42 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 43 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 44 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 45 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 46 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 47 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 48 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 49 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 50 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 51 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 52 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 53 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 54 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 55 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 56 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 57 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 58 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 59 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 60 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 61 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 1 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 62 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 1 1 63 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0

  42. Walsh Code Function in Forward Link Pilot Sync FW Traffic (for user #2) FW Traffic (for user #1) Paging FW Traffic (for user #3) • A Mobile Station receives a Forward Channel from a sector in a Base Station. • The Forward Channel carries a composite signal of up to 64 forward code channels. • Some code channels are traffic channels and others are overhead channels. • A set of 64 mathematical codes is needed to differentiate the 64 possible forward code channels. • The codes in this set are called “Walsh Codes”

  43. Short PN: 4-bits register example 0 0 0 1 1 1 0 0 0 1 1 0 p1 p2 p3 p4 0 0 1 1 1 1 0 1 1 0 1 0 0 1 0 1 p4 1 1 1 0 p4 p2 p3 0 1 1 1 p5= p1 + p4 1 1 1 1 1 0 1 1 1 0 0 1 1 0 0 0 0 1 0 0 p4 p5 p2 p3 0 0 1 0 0 0 0 1 The PN sequences are deterministic and periodic. • The length of the generated string is 2n-1, where “n” is the number of elements in the register • The number of ones in the sequence are equal to the number of zeros plus 1

  44. Short PN Sequences 32,768 chips long 26 2/3 ms. (75 repetitions in 2 sec.) I Q Unique Properties: Short PN Sequence vs. Itself @ 0 Offset I Q I Q 100% Correlation: All bits = 0 Short PN Sequence vs. Itself @ Any Offset I Q I Q Orthogonal: 16,384 1’s + 16,384 0’s The two Short PN Sequences, I and Q, are 32,768 chips long • Together, they can be considered a two-dimensional binary “vector” with distinct I and Q component sequences, each 32,768 chips long • Each Short PN Sequence (and, as a matter of fact, any sequence) correlates with itself perfectly if compared at a timing offset of 0 chips • Each Short PN Sequence is special: Orthogonal to a copy of itself that has been offset by any number of chips (other than 0)

  45. Short PN Function in Forward Link Up to 64 Code Channels Up to 64 Code Channels A B • Each Sector in each Base Station is transmitting a Forward Traffic Channel containing up to 64 forward code channels. • A Mobile Station must be able to discriminate between different Sectors of different Base Stations. • Two binary digit sequences called the I and Q Short PN Sequences (or Short PN Codes) are defined for the purpose of identifying sectors of different base stations. • These Short PN Sequences can be used in 512 different ways in a CDMA system. Each one of them constitutes a mathematical code which can be used to identify a particular sector.

  46. Long PN:4-bits shift register example 0 0 0 1 1 1 0 0 0 1 1 0 0 0 1 1 1 1 0 1 1 0 1 0 0 1 0 1 1 1 1 0 0 1 1 1 1 1 1 1 1 0 1 1 1 0 0 1 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 Original PN sequence XOR mask AND AND AND AND ( XOR ) New PN sequence Attention:different mask lead to different offset!

  47. The Long PN Sequence Long Code Register (@ 1.2288 MCPS) AND Public Long Code Mask (STATIC) 1 1 0 0 0 1 1 0 0 0 E S N = User Long Code Sequence (@1.2288 MCPS) S U M Modulo-2 Addition • Each mobile station uses a unique User Long Code Sequence generated by applying a mask, based on its 32-bit ESN, to the 42-bit Long Code Generator which was synchronized with the CDMA system during the mobile station initialization. • Generated at 1.2288 Mcps, this sequence requires 41 days, 10 hours, 12 minutes and 19.4 seconds to complete. • Portions of the User Long Codes generated by different mobile stations for the duration of a call are not exactly orthogonal but are sufficiently different to permit reliable decoding on the reverse link.

  48. Long PN Functionin Reverse Link RV Traffic from M.S. #1837732008 RV Traffic from M.S. #1997061104 RV Traffic from M.S. #1994011508 System Access Attempt by M.S. #2000071301 (on access channel #1) • The CDMA system must be able to identify each Mobile Station that may attempt to communicate with a Base Station. • A very large number of Mobile Stations will be in the market. • One binary digit sequence called the Long PN Sequence (or Long PN Code) is defined for the purpose of uniquely identifying each possible reverse code channel. • This sequence is extremely long and can be used in trillions of different ways. Each one of them constitutes a mathematical code which can be used to identify a particular user (and is then called a User Long Code) or a particular “user Reverse Traffic channel”.

  49. Main Content • Definitions of CDMA and How to realize • Spread spectrum modulation • Spreading codes used in CDMA • Vocoding in CDMA

  50. Variable Rate Vocoding • CDMA uses a superior Variable Rate Vocoder • Full rate during speech • Low rates in speech pauses • Increased capacity • More natural sound • Voice, signaling, and user secondary data may be mixed in CDMA frames

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