Adjacent Channel results for Four Channels IEEE 802.11-02/365 May 2002 May 2002 Adjacent Channel results for Four Channels Steve Halford Michael Seals Mark Webster Steve Halford, Intersil Steve Halford, Intersil Corp

Background Doc 02/220r0 proposed optional Channel 0 May 2002 Background Doc 02/220r0 proposed optional Channel 0 Allows for 4 20 MHz channels at 2.4 GHz Presented in March Meeting (St. Louis) Two phone conference held to discuss Channel spacing closer than .11b Spacing same as 802.11a 5 GHz has many more channels Can layout channel re-use to avoid adjacent channels 4 channels is insufficient to avoid adjacent Forbidden Band is also 5 MHz closer Will require more back-off to meet Steve Halford, Intersil

May 2002 Simulation Model Used Steve Halford, Intersil

Spectral Control via Masks May 2002 Spectral Control via Masks TGg Draft Spec allows for two different mask Both masks are relative to peak of the main lobe Picture of Masks Steve Halford, Intersil

Power Amplifier Model P_sat= 24.2 dBm P_1dB = 21.5 dBm May 2002 Steve Halford, Intersil

ACI Results ACI increases with narrower spacing May 2002 ACI Results Waveform Power out (dBm) ACI (dBm) ACR (dB) Channel Spacing (MHz) Limit OFDM 19.91 -6.53 26.43 20 .11a Mask QPSK 20.35 -12.36 32.71 .11b Mask -12.66 32.57 25 -19.39 39.74 ACI increases with narrower spacing OFDM increases by 6.13 dB PSK/PBCC increases by 6.73 dB What impact will this have on performance? Steve Halford, Intersil

Forbidden Band Results May 2002 Forbidden Band Results Waveform Power out (dBm) Back-off 1-dB (dB) Channel Spacing (MHz) Distance to FB (MHz) OFDM 11.11 10.39 20 17 QPSK 16.05 5.45 15.95 6.55 25 22 18.83 2.67 PSK/PBCC modes will need 2.78 dB more back-off OFDM modes will need 4.94 dB more back-off Steve Halford, Intersil

Conclusions & Questions May 2002 Conclusions & Questions Narrower spacing increases interference From 6.73 to 12.86 dB increase over existing ACI Forbidden Band compliance is possible Additional Back-off required QPSK: 2.79 dB OFDM: 4.94 dB Is this level of interference acceptable? Is 4-channel the best approach to getting more channels? Ex: 8-channels are possible using half-rate clocks Steve Halford, Intersil