1. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 1 System capacity and cell radius comparison with several high data rate WLANs Satoru Hori, Yasuhiko Inoue, Tetsu Sakata, Masahiro Morikura NTT hori@ansl.ntt.co.jp

2. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 2 Approach to 100 Mbps WLAN PHY Layer Requirements for Next Generation WLAN - Data rate above 100 Mbps - Enough cell radius - Large system capacity Comparison between several candidates - Extension of IEEE 802.11a - Data rate of 108 Mbit/s (twice as 54 Mbit/s in IEEE 802.11a)

3. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 3 Four candidates extending IEEE 802.11 a A: double clock rate clock rate of the system is twice as fast as that of IEEE 802.11 a e.g. clock rate: 20 MHz 40 MHz B: double sub-carrier numbers number of sub-carriers is twice as many as that of IEEE 802.11 a e.g. 52 sub-carriers 104 sub-carriers C: increasing M in M-ary QAM-OFDM increasing the number of bits in M-ary QAM on each sub-carrier e.g. 64 QAM 4096 QAM D: OFDM/SDM (multi-carrier MIMO) system using multiple transmit and receive antennas each antenna transmit different data to increase transmit data rate e.g. 2 transmit antennas and 2 receive antennas Reference A. van Zelst, R. van Nee, and G. A. Awater, “Space Division Multiplexing (SDM) for OFDM systems,” Proc. IEEE VTC2000-spring, vol. 2, pp.1070-1074, May 2000. P.Vandenameele, L. V. D.Perre, M. G. E.engels, B. Gyselinckx, and H. J. D. Man, “A Combined OFDM/SDMA Approach,” IEEE J. Sel. Areas in Commun., vol. 18, no. 11, Nov. 2000.

4. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 4 Parameters of each system A: double clock rate B: double sub-carriers C: 4096 QAM- OFDM D: SDM- OFDM Data rate 108 Mbit/s Band width 33.1 MHz 16.6 MHz Number of channels 6 channels (USA) 6 channels (USA) 12 channels (USA) 12 channels (USA) Number of sub-carriers 52 10452 symbol length 2  s 4  s GI length400 ns 800 ns Mod. scheme64 QAM 4096 QAM64 QAM Number of antennas receiver : 2 (diversity) receiver : 2 (diversity) receiver : 2 (diversity) transmitter : 2 receiver : 2

5. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 5 Cell Radius Calculation d = ( / 4  ) 10 (Lp /10  ) [m] L p = P t + G t + G r - P r [dB] P r = N p + C r + D f [dBm] N p = N f + 10log 10 (kB w T) + 30 [dBm]  : propagation loss coefficient : wave length ( = c/f = 0.0576923 [m] for 5.2GHz ) k : Boltzman coefficient (= 1.38 * 10 -23 [J/K] ) C r : required CNR to realize PER of 1% d : cell radius L p : allowed propagation loss P t, P r : transmit power and required received power, respectively G t, G r : the gain of transmit antenna and receive antenna, respectively (was assumed to be 0 dBi) N p : noise power D f : degradation due to various factors (was assumed to be 6 dB) N f : noise figure of the receiver (was assumed to be 7 dB) B w : bandwidth of signals T : temperature (was assumed to be 300 K)

6. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 6 System Capacity Calculation Th=(R *  * Nch)/C=3sqrt(3) * Nch * R *  /(2  * 10 2CIR/10  ) Th : Maximum throughput R : data rate of PHY layer ( = 108 Mbit/s)  : MAC efficiency for throughput (was assumed to be 1.0) Nch : Number of channels ( = 12 for 20MHz band width and 6 for 40MHz band width ) (Lower, Middle and Upper UNII bands) C : Cluster size ( = Interference area / Cell space ) CIR : Required CIR to achieve PER of 1% Cell space Interference area

7. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 7 Required CNR 10 -3 10 -2 10 10 0 152025303540 CNR [dB] PER A:double clock rate B:double sub-carriersC: 4096 QAM-OFDM D: SDM-OFDM Data rate 108 Mbit/s Packet size 64 byte Exponentially decaying Rayleigh fading (delay spread 100 ns) No space correlation Ideal synchronization Ideal channel estimation FEC coding rate = 3/4 constraint length = 7 5 bit soft-decision diversity (A, B, C) Maximum ratio combining

8. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 8 Required CIR Data rate 108 Mbit/s Packet size 64 byte Exponentially decaying Rayleigh fading (delay spread 100 ns) No space correlation Ideal synchronization Ideal channel estimation FEC coding rate = 3/4 constraint length = 7 5 bit soft-decision diversity (A, B, C) Maximum ratio combining 10 -3 10 -2 10 10 0 152025303540 A:double clock rate B:double sub-carriers C: 4096 QAM-OFDM D: SDM-OFDM CNR [dB] PER

9. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 9 Performance Comparison Required CNR A: double clock rate B: double sub-carriers C: 4096 QAM- OFDM D: SDM- OFDM Transmit power Propagation loss coefficient  Cell radius Required CIR Cluster size System capacity 19.5 dB18.8 dB36.1 dB29.2 dB 13 dBm 3.1 11.4 m12.0 m4.1 m6.9 m 20.3 dB20.0 dB37.2 dB29.8 dB 24.723.6303.7101.2 26.4 Mbit/s27.6 Mbit/s4.2 Mbit/s12.9 Mbit/s

10. doc.: IEEE 802.11-02/159r0 Submission March 2002 S. Hori, Y Inoue, T. Sakata, M. Morikura / NTT. Slide 10 Conclusion Systems with 40 MHz band width (A and B) - CNR and CIR are pragmatic. - Total number of channels is one half of that of IEEE 802.11 a. e.g. 6 channels in USA, only 2 channels in Japan Systems with 20 MHz band width (C and D) - Total number of channels is same as that of IEEE 802.11 a. - CNR and CIR must be improved significantly.