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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 1 OFDM System Performance Karen Halford, Steve Halford and Mark Webster
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 2 Outline of Proposal Presentations TGg Regulatory Approval Plan Speaker: Jim Zyren Overview of OFDM for High Rate Speaker: Steve Halford Reuse of 802.11b Preambles with OFDM Speaker: Mark Webster Ultra-short Preamble with HRb OFDM Speaker: Mark Webster OFDM System Performance Speaker: Steve Halford Power Am Effects for HRb OFDM Speaker: Mark Webster Channelization for HRb OFDM Speaker: Mark Webster Phase Noise Sensitivity for HRb OFDM Speaker: Jim Zyren Implementation and Complexity Issues for OFDM Speaker: Steve Halford Why OFDM for the High Rate 802.11b Extension? Speaker: Jim Zyren
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 3 Outline of Presentation 5.1 AWGN Performance 5.2 Rayleigh Fading Performance 5.3 Multipath Performance 5.3.1 Exponential Channel with Flat Fading 5.3.2 Exponential Channel without Flat Fading (Normalized) 5.3.3 PER sweeps from 1% to 10 % 5.4 Throughput Performance 5.5 Performance Against CW Jammer (FCC15.247 Test)
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 4 5.1 AWGN Performance: 100 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 5 5.1 AWGN Performance: 1000 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 6 5.1 AWGN Performance: 2346 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 7 5.1 AWGN Performance: 1% and 10 % PER for 1000 Byte Packets Eb/No required for 1 % PER Eb/No required for 10 % PER
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 8 5.2 Rayleigh Fading Performance: Block Diagram Transmitter Model Packet Length Data Rate Rayleigh Coefficient Receiver Model Measure Packet Error Rate Packet Error Rate Measure energy per bit Calculate Noise Power (N 0 ) Generate Noise x+
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 9 5.2 Rayleigh Fading Performance: 1000 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 10 5.2 Rayleigh Fading Performance: 1% and 10 % PER for 1000 Byte Packets Eb/No required for 1 % PER Eb/No required for 10 % PER
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 11 5.3.1 Multipath Performance with Flat Fading: Block Diagram Exponential Channel Model Transmitter Model Packet Length Data Rate Sample Rate Delay Spread Receiver Model Measure Packet Error Rate Packet Error Rate Measure energy per bit Calculate Noise Power (N 0 ) Generate Noise
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 12 5.3.1 Multipath Performance with Flat Fading: Matlab ® Code
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 13 5.3.1 Multipath Performance with Flat Fading: Eb/No
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 14 5.3.1 Multipath Performance with Flat Fading: SNR
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 15 5.3.2 Multipath Performance without Flat Fading: Block Diagram Exponential Channel Model Transmitter Model Packet Length Data Rate Sample Rate Delay Spread Receiver Model Measure Packet Error Rate Packet Error Rate Generate Noise Measure energy per bit Calculate Noise Power (N 0 )
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 16 5.3.2 Multipath Performance without Flat Fading: Eb/No
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 17 5.3.2 Multipath Performance without Flat Fading: SNR
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 18 5.3.3: Multipath Sweeps: 1% to 10% For each modulation mode detemine and state the SNR (Es/No) at which in AWGN only, the waveform can achieve a PER of 0.01 for packets lengths of 1000B. Using the multipath model used in 23b above, fix the amount of AWGN at the 0.01 PER level for AWGN only. Increase the RMS delay spread until the PER for 1000B packets reach 0.1. State the RMS delay spread at this point. Comparison Item 24 Answer: 0.0 nSeconds for all rates Why ?
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 19 5.3.3 Multipath Sweeps: 1% to 10% PER Curves are very steep -- about 2 dB separates the 1% from the 10 % point
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 20 5.3.3 Multipath Sweeps: 1% to 10% Rayleigh fading causes frequent swings to low SNR level
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 21 5.3.3 Multipath Sweeps: 1% to 10% For each modulation mode detemine and state the SNR (Es/No) at which 25 nSeconds RMS delay, the waveform can achieve a PER of 0.01 for packets lengths of 1000B. Using the multipath model used in 23c above, fix the amount of AWGN at the 0.01 PER level for 25 nSeconds RMS delay. Increase the RMS delay spread until the PER for 1000B packets reach 0.1. State the RMS delay spread at this point. What we ran in place of Comparison Item 24
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 22 5.3.3 Multipath Performance: PER sweeps from 1% to 10%
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 23 5.4 Throughput Performance 5.4.1 Preamble Structures 5.4.2 ACK Assumptions 5.4.3 Throughput Analysis 5.4.3.1 Tables of 100, 1000, 2346 Byte Packets 5.4.3.2 Plots for full range of packet sizes 5.4.4 Throughput analysis for varying durations of overhead
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 24 5.4.1 Preamble Structures: Long and Short Preambles PREAM/HDR 72 BITS @ 1 Mbps PREAMBLE/HEADER 802.11 HRb LONG PREAMBLE 802.11 HRb SHORT PREAMBLE 96 usecs 192 usecs Data Payload 10.9 usecs PSDU SELECTABLE OFDM Symbols @ 6.6, 9.6, 13.2, 19.8, 26.4, 39.3, 52.8 or 59.4 Mbps PSDU SELECTABLE OFDM Symbols @ 6.6, 9.6, 13.2, 19.8, 26.4, 39.3, 52.8 or 59.4 Mbps OFDM SYNC OFDM SYNC 10.9 usecs ~6 usecs Signal Extension ~6 usecs Signal Extension
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 25 5.4.1 Preamble Structures: Ultra-Short Preamble Data Payload PSDU SELECTABLE @ 6.6, 9.9, 13.2, 19.8, 26.4, 39.6, 52.8 or 59.4 Mbps SIGNAL SYMBOL Data Rate # bytes of data Long SYNC 16 usecs3.6 usecs 12 Short Syncs Rep’s Signal Extension ~6 usecs Proposed Ultra-Short Preamble
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 26 5.4.2 ACK Assumptions SIFSFragment 1 SIFSACK 1 source destination DIFSData SIFSACK source destination 1) No RTS/CTS OR MPDU < RTS_Threshold: DIFS RTS SIFSCTS source destination 2) RTS/CTS and/or MPDU > RTS_Threshold: Data SIFSACK 3) Middle of Fragmented Transmission: Many different scenarios, but the constant is: {MPDU, SIFS, ACK} SIFS
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 27 5.4.2 ACK Assumptions (continued) Packet Header PSDU SELECTABLE OFDM Symbols @ 6.6, 9.6, 13.2, 19.8, 26.4, 39.3, 52.8 or 59.4 Mbps OFDM PAD ~6 usecs Packet HeaderACK SIFS 112 Bits @ 6.6 Mbps = 20 usec
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 28 5.4.3.1 Throughput for 100 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 29 5.4.3.1 Throughput for 1000 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 30 5.4.3.1 Throughput for 2346 Byte Packets
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 31 5.4.3.2 Throughput with ACK
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 32 5.4.3.2 Throughput without ACK
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 33 5.4.4 Comparison of Throughput for Variable Overhead for 100 Byte MPDU
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 34 5.4.4 Comparison of Throughput for Variable Overhead for 1000 Byte MPDU
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 35 5.4.4 Comparison of Throughput for Variable Overhead for 2346 Byte MPDU
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 36 5.4.5 Aggregate Throughputs for 2.4 GHz Our proposal allows for 3 channels in US 2.4 GHz band Each channel can coexist in the same area Aggregate throughput is 3 times single channel throughput
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 37 5.5 CW Jammer Test Description CW jammer test steps a CW tone across the signal band in 50 kHz steps. At each step, the jamming level required to to produce the recommended BER is determined. The worst 20% of the J/S levels are discarded and the smallest of the remaining J/S is used as the jamming margin. Processing gain is then calculated according to the following:
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doc.: IEEE 802.11-00/392 Submission November 2000 K. Halford, S. Halford and M. Webster, IntersilSlide 38 5.5 Performance Against CW Jammer G p = (S/N) 0 + M j + L sys
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