# Doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Range vs. Rate Comparison of Remaining IEEE 802.11g Proposals: PBCC and CCK-OFDM.

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doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Range vs. Rate Comparison of Remaining IEEE 802.11g Proposals: PBCC and CCK-OFDM Matthew B. Shoemake, Ph.D. Anuj Batra, Ph.D. Texas Instruments, Inc. Dallas, TX shoemake@ti.com

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Objective To calculate the Range vs. Rate and Coverage Area vs. Rate for the PBCC proposal and the CCK-OFDM proposal using standard and verifiable methods

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Approach Use PER vs. SNR curves for PBCC and CCK-OFDM in conjunction with standard IEEE 802.15.2 path loss models as well as power amplifier back off and maximum sustainable throughput values from authors of PBCC and CCK-OFDM

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Calculation of Receiver Power The received power is taken as a simple function of the actual Effective Isotropic Radiated Power (EIRP), the path loss using the IEEE 802.15.2 indoor model, and the PA backoff: P RX = P MAX,TX – P Pathloss – P PA Backoff Assume P MAX = 100mW

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI IEEE 802.15.2 Path Loss Model Assumes line of sight for less than 8m: L path = 10 log (4  r 2 / ) dB,r < 8m After 8m, assumes indoor path loss exponent of 3.3: L path = –37.7 + 10 log(4  r 3.3 / ) dB,r > 8m Where: = wavelength @ 2.45 GHz (0.1224 m) r = range (m) Reference: 802.15 doc. 00/134

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Power Amplifier Back-off The PA Backoff for the remaining proposals are: PA BackOff CCK-OFDM = 6 dB PA BackOff BARKER/CCK/PBCC = 4 dB Using the same radio, CCK-OFDM requires 2 dB more back off than Barker/CCK/PBCC systems. Note that CCK-OFDM has lower average power than Barker/CCK/PBCC.

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Calculation of Noise at Receiver The noise is taken as a function of the thermal noise received through an ideal matched filter for each modulation and a noise figure: N = N thermal + N NoiseFigure Assume N NoiseFigure = 6 dB

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Thermal Noise Floor and Spectral Masks The thermal noise floor is: –114dBm/MHz An ideal matched filter will capture a noise power of: –OFDM: –95.9 dBm –PBCC: –103.6 dBm A CCK-OFDM matched filter will capture 7.7 dB more noise than a Barker/CCK/PBCC matched filter!

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Calculation of Received SNR The received SNR is then simply calculated as the ratio of the received power to the noise with the addition of a multipath loss factor SNR = P RX / N – Loss where Loss = Implementation Loss + Multipath Margin Assume Loss = 10 dB

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Calculation of Throughput Maximum Sustainable Throughputs (MST) from doc. 01/059 by Halford, Webster and Zyren are used. –Assumed data length = 1000B –IEEE 802.11b short preamble –With ACK packets –No backoff (only DIFS included; similar to 802.11e HCF) The throughput T PER is calculated as the MST divided by the average number of attempts to successfully send a packet. (Note that this is a function of the PER.)

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI PER vs. SNR for IEEE 802.11b + PBCC 22 Plot relates the Packet Error Rate (PER) for for each modulation to the ratio of the signal strength at the receiver to the noise strength at the receiver.

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI PER vs. SNR for CCK-OFDM

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Range vs. Rate Performance

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Area vs. Rate Performance

doc.: IEEE 802.11-01/286r0 Submission May 2001 Shoemake and Batra, TI Conclusion PBCC-22 has larger range and coverage area than either CCK or CCK-OFDM. 802.11a has higher Maximum Sustainable Throughputs than CCK-OFDM with the same range.

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