1. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 1 Maximum Received Power for 802.11g Steve Halford Mark Webster

2. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 2 Maximum Received Power Current 802.11g standard requires less than 10% PER for 1000 byte packet with –20dBm input signal measured at the antenna (Subclause 19.3.3.10.2)Current 802.11g standard requires less than 10% PER for 1000 byte packet with –20dBm input signal measured at the antenna (Subclause 19.3.3.10.2) –802.11a requires –30dBm (Subclause 17.3.10.4) for all OFDM data rates –802.11b requires PER less than 8% –10 dBm (Subclause 18.4.8.2 ) for CCK-11 –802.11 requires PER less than 8% at –4 dBm (Subclause 15.4.8.2) for Barker-2 This spec sets the closest placement of two radiosThis spec sets the closest placement of two radios

3. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 3 Received Power Calculation

4. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 4 Assumptions & Values Used Transmit Power: +20dBmTransmit Power: +20dBm –Measured at the antenna –+20 dBm is current FCC limit for TGg at 2.4 GHz Power is limited to maximum of 100 mWattsPower is limited to maximum of 100 mWatts Antenna Gain is assumed to be +2 dBiAntenna Gain is assumed to be +2 dBi Assume free space loss characteristicsAssume free space loss characteristics –No loss due to multipath

5. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 5 Results for +20dBm Transmit Power

6. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 6 Comparison to 5 GHz 802.11a requirement 802.11a requires –30dBm input power802.11a requires –30dBm input power –Greater free space loss for same size antenna at 5.2 GHz –Expect lower receive power for same distance

7. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 7 Summary of Results & Conclusions Lower loss for.11g radios means that a -30 dBm requires radios to be 3.85 m apart!.11a radios can be no closer than 1.8 meters Same distance at 2.4 GHz translates to –23.4 dBm max receive power To improve performance (& make more like.11b) Selected -20 dBm

8. doc.: IEEE 802.11-02/089 Submission January 2002 Steve Halford, IntersilSlide 8 Appendix A: Matlab Code distances = 0.05:0.1:2.5; % distances in meters P_T = 15; % Transmit Power in dBm G_A = 2; % Antenna Gain in dB c = 2.997e8; % Speed of light in m/s f = 2.45e9; % Frequency in Hz lambda = c/f; % wavelength in meters path_loss_vector = 20*log10(lambda./(4*pi*distances)); % Path loss for r^2 loss received_power_vector = P_T + G_A + path_loss_vector; % Received power in dBm % Plotting the results plot(distances,received_power_vector) ylabel('Received Power in dBm') xlabel('Distance in meters') grid