1. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 1 of 22 WCDMA Air Interface Training Part 3 CDMA Capacity Considerations

2. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 2 of 22 Cell Planning FDMA systems äFrequency Reuse Planning äSNR Link Budget TDMA systems äFrequency Reuse Planning äTimeslot Allocation äSNR Link Budget CDMA systems äCode Reuse Planning äSNR Link Budget äInterference Link Budget

3. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 3 of 22 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4 Frequency Reuse Basic Reuse Pattern of 7 F1F1 F2F2 F7F7 F3F3 F6F6 F5F5 F4F4

4. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 4 of 22 Frequency Reuse Reuse Patterns of 4, 3 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F4F4 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 Reuse = 4 Reuse = 3

5. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 5 of 22 Frequency Reuse Cell Sectorization 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 1 2 3 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 5 6 Reuse Pattern 7/21

6. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 6 of 22 CDMA Efficiency vs. FDMA, TDMA Notes: [1] GSM also uses frequency reuse of 4, frequency hopping, and other techniques to optimize cell planning efficiencies. [2] Users per cell is calculated in a 5 MHz carrier, assuming a frequency reuse of 7 for FDMA, TDMA; 1 for CDMA [3] All FDMA, TDMA, and CDMA systems can make proportional capacity gains by using cell sectorization patterns such as 7/21, 4/12, etc. [4] Theoretical capacity of cdma2000 and WCDMA depends on Orthogonal Code allocations, and is therefore dependent on the mix of users and data rates. Practical capacity will depend on these and many other factors.

7. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 7 of 22 CDMA Code Planning PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 PN 1 PN 2 PN 7 PN 3 PN 6 PN 5 PN 4 CDMA Frequency Reuse: 1 PN Code Reuse Factor: 7 Sectorization: 3-Sector (7/21) Reuse Codes available for code planning: IS-95: 512* cdma2000:512* WCDMA:512 * IS-95 and cdma2000 use 512 discrete time offsets of the same PN code to facilitate cell planning. In practice, IS-95 consecutive codes are avoided in order prevent potential time overlap of transmissions from widely spaced cells. The maximum number of available codes is therefore 256.

8. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 8 of 22 CDMA Capacity What determines the capacity of an FDMA system? ä ä ä What determines the capacity of a TDMA system? ä ä ä What determines the capacity of a CDMA system? ä ä ä ä

9. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 9 of 22 CDMA Capacity Factors influencing CDMA capacity äE b /N 0 (Energy per bit - to - Noise ratio) Limited by transmit power; All base station transmissions share a single transmit power budget äE b /I 0 (Energy per bit - to Interference Ratio) Uplink: SSMA interference from mobiles in same cell, mobiles in other cells Downlink: SSMA interference from surrounding base stations, distant base stations Excessive interference associated with imperfect power control Spread Spectrum Processing Gain is reduced at higher data rates äMultipath reflections, doppler shift, near-far ratio, obstructions, etc.

10. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 10 of 22 CDMA Capacity Example of E b /N 0 and E b /I o capacity limitations Cell 1 Cell 2 MS1 MS2 MS3    Cell 1 cannot accommodate MS3 because:  Cell 2 cannot accommodate MS2 because:

11. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 11 of 22 CDMA Capacity Digital SNR: E b /N o Energy per bit (E b ) equals the average signal power (S) divided by the data bit rate (R b ) Energy per bit (E b ) - to - Noise Ratio The Signal-to-Noise Ratio (SNR) times the SSMA Processing Gain Noise power density (N 0 ) The total noise power in the signal bandwidth, divided by the signal bandwidth

12. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 12 of 22 CDMA Capacity E b /N o vs. Probability of Error (BPSK, QPSK) 02468101214 10 -12 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 Eb/No (dB) P e (Probability of bit error) For QPSK Modulation, an E b /N 0 of ~ 7.5 dB is required to achieve a Pe of 10 -3

13. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 13 of 22 CDMA Capacity Uplink Capacity Limit due to SSMA Interference Interfering Signals Desired Signal Signal-to-Interference Ratio The signal-to-interference ratio for any single user. (Assumes perfect power control; all users received at the same power) Energy per bit (E b ) - to - Interference Ratio The Signal-to-Interference ratio times the SSMA Processing Gain

14. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 14 of 22 CDMA Capacity Uplink Capacity Limit due to SSMA Interference Solving for M (The number of users that can be accommodated at a given E b /I 0 ): Assuming that M >> 1; The number of users equals the SSMA processing Gain divided by the desired E b /I 0 Taking into account Voice Activity Factor: Voice Activity Factor ranges from 0.35 to 0.65

15. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 15 of 22 CDMA Capacity Theoretical Uplink Capacity Example (one MS, one cell) G p = 128Spread Spectrum Processing Gain; v f = 0.5 Case I: Desired P e = 10 -3 ; E b /I 0 = 7.5 dB = 5.62 Case II: Desired P e = 10 -2 ; E b /I 0 = 5.1 dB = 3.23 Approximately 45 SSMA users can co-exist in a single-cell system with a P e of 10 -3 if each has a processing gain of 128

16. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 16 of 22 CDMA Capacity Uplink Capacity in a multi-cell network Required E b /N o in a single-cell network: Required E b /N o in a multi-cell network: Interference from other cells during soft handover is given by f; Inter-cell interference factor increases with the standard deviation of path loss; typical values of (f) range from 0.4 to 2.6 (V. Garg, “IS-95 and cdma2000”, Table 13-1) Also Taking into account other cell interference

17. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 17 of 22 CDMA Capacity Example 1: Uplink Capacity in a multi-cell IS-95 network SSMA Bandwidth (B)1.25 MHz Intercell Interference f = 0.6 (typical for 3-way soft handover, path loss deviation 8 dB) Voice Activity Factor V f = 0.5 Required P e 10 -3 (E b /I 0 = 7.5 dB = 5.62) for 9.6 kbps 10 -4 (E b /I 0 = 8.5 dB = 7.62) for 14.4 kbps Case I: Data rate = 9.6 kbps; G p = 1.2288 Mcps / 9.6 kbps = 128 Case II: Data rate = 14.4 kbps; G p = 1.2288 Mcps / 14.4 kbps = 85.33

18. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 18 of 22 CDMA Capacity Example 1: Uplink Capacity in WCDMA SSMA Bandwidth (B)3.84 MHz (equal to W-CDMA chip rate for this example) Intercell Interference f = 0.6 (typical for 3-way soft handover, path loss deviation 8 dB) Voice/data activity 0.5 Required P e 10 -3 (E b /I 0 = 5.62) Case I: Data rate = 30 ksps; G p = 3.84 Mcps / (60 kbps/2) = 128 Case II: Data rate = 960 ksps; G p = 3.84 Mcps / (1.92 Mbps/2) = 4 Many other factors will affect actual capacity... see next page

19. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 19 of 22 CDMA Capacity Other factors influencing capacity äOther Factors that increase capacity: Cell Sectorization Antenna Gain Antenna Diversity Soft Handover Macrodiversity Gain Use of higher-strength error protection (e.g., turbo coding) Statistical multiplexing of packet data users äOther Factors that decrease capacity: Imperfect Power Control Downlink Interference from other Base Stations Absorption (body, terrain, structural, atmospheric...) Use of lower strength error protection on high-speed channels Multipath fading Frequency-selective fading

20. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 20 of 22 CDMA Capacity Downlink Capacity äFundamental Capacity Limitation is available RF transmit power One RF power budget must be split between all Mobile Stations! Fixed portion of RF power Budget allocated to Pilot, Broadcast, Paging channels äSSMA interference from other Base Stations Growing problem in Microcellular and Hierarchy topologies äTraffic channel power is allocated based on Mobile Station needs More power allocated to distant MS’s; less to nearby MS’s IS-95B provides 20msec downlink power update for 14.4 kbps data rate WCDMA, cdma2000 use fast power control on the downlink traffic channels

21. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 21 of 22 Soft Blocking Soft vs. Hard Blocking FDMA/TDMA: When all frequencies and/or timeslots are used, calls are blocked CDMA: When interference levels are too high, calls are blocked Making enough money? Adjust Interference Limit Yes No Yes New User requests Access Interference within limits? Grant Access Block Access No Admission Control Interference within limits? Send users to other cells, frequencies, or systems Reduce non-CBR data rates Reduce packet data throughput Reduce error protection Ignore downlink TPC from MS Selectively drop calls Yes No Load (Congestion) Control

22. 3/038 13 - EN/LZU 108 5306 Rev A WCDMA Air Interface Part 3: 22 of 22 Summary: CDMA Capacity Summary äCell capacity not determined by size of Orthogonal Code set! äUplink capacity is usually interference-limited äDownlink capacity limited by both RF power allocation to traffic channels and interference from other base stations Experience from IS-95 äTypical per-sector capacity of 13 to 16 mobile stations Some operators report up to 20 mobiles per sector on a single CDMA carrier äDL capacity sometimes higher, sometimes lower than UL capacity And in the final analysis...