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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.

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Presentation on theme: "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."— Presentation transcript:

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

2 doc.: IEEE /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

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

4 doc.: IEEE /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 indoor model, and the PA backoff: P RX = P MAX,TX – P Pathloss – P PA Backoff Assume P MAX = 100mW

5 doc.: IEEE /286r0 Submission May 2001 Shoemake and Batra, TI IEEE 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 = – log(4  r 3.3 / ) dB,r > 8m Where: = 2.45 GHz ( m) r = range (m) Reference: doc. 00/134

6 doc.: IEEE /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.

7 doc.: IEEE /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

8 doc.: IEEE /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!

9 doc.: IEEE /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

10 doc.: IEEE /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 b short preamble –With ACK packets –No backoff (only DIFS included; similar to e 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.)

11 doc.: IEEE /286r0 Submission May 2001 Shoemake and Batra, TI PER vs. SNR for IEEE b + 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.

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

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

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

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


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