OFDM System Performance November 2000 OFDM System Performance Karen Halford, Steve Halford and Mark Webster K. Halford, S. Halford and M. Webster

Outline of Proposal Presentations November 2000 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: Mark Webster Implementation and Complexity Issues for OFDM Speaker: Steve Halford Why OFDM for the High Rate 802.11b Extension? Speaker: Jim Zyren K. Halford, S. Halford and M. Webster

Outline of Presentation November 2000 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) K. Halford, S. Halford and M. Webster

5.1 AWGN Performance: 100 Byte Packets November 2000 5.1 AWGN Performance: 100 Byte Packets K. Halford, S. Halford and M. Webster

5.1 AWGN Performance: 1000 Byte Packets November 2000 5.1 AWGN Performance: 1000 Byte Packets K. Halford, S. Halford and M. Webster

5.1 AWGN Performance: 2346 Byte Packets November 2000 5.1 AWGN Performance: 2346 Byte Packets K. Halford, S. Halford and M. Webster

5.1 AWGN Performance: 1% and 10 % PER for 1000 Byte Packets November 2000 5.1 AWGN Performance: 1% and 10 % PER for 1000 Byte Packets Eb/No required for 1 % PER Eb/No required for 10 % PER K. Halford, S. Halford and M. Webster

5.2 Rayleigh Fading Performance: Block Diagram November 2000 5.2 Rayleigh Fading Performance: Block Diagram Calculate Noise Power (N0) Generate Noise Measure energy per bit Measure Packet Error Rate Transmitter Model Packet Error Rate x + Receiver Model Rayleigh Coefficient Packet Length Data Rate K. Halford, S. Halford and M. Webster

5.2 Rayleigh Fading Performance: 1000 Byte Packets November 2000 5.2 Rayleigh Fading Performance: 1000 Byte Packets K. Halford, S. Halford and M. Webster

5.2 Rayleigh Fading Performance: 1% and 10 % PER for 1000 Byte Packets November 2000 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 K. Halford, S. Halford and M. Webster

5.3.1 Multipath Performance with Flat Fading: Block Diagram November 2000 5.3.1 Multipath Performance with Flat Fading: Block Diagram Calculate Noise Power (N0) Generate Noise Measure energy per bit Measure Packet Error Rate Packet Error Rate Exponential Channel Model Transmitter Model Receiver Model Packet Length Data Rate Sample Rate Delay Spread K. Halford, S. Halford and M. Webster

5.3.1 Multipath Performance with Flat Fading: Matlab® Code November 2000 5.3.1 Multipath Performance with Flat Fading: Matlab® Code K. Halford, S. Halford and M. Webster

5.3.1 Multipath Performance with Flat Fading: Eb/No November 2000 5.3.1 Multipath Performance with Flat Fading: Eb/No K. Halford, S. Halford and M. Webster

5.3.1 Multipath Performance with Flat Fading: SNR November 2000 5.3.1 Multipath Performance with Flat Fading: SNR K. Halford, S. Halford and M. Webster

5.3.2 Multipath Performance without Flat Fading: Block Diagram November 2000 5.3.2 Multipath Performance without Flat Fading: Block Diagram Calculate Noise Power (N0) Generate Noise Measure energy per bit Measure Packet Error Rate Exponential Channel Model Transmitter Model Receiver Model Packet Error Rate Packet Length Data Rate Sample Rate Delay Spread K. Halford, S. Halford and M. Webster

5.3.2 Multipath Performance without Flat Fading: Eb/No November 2000 5.3.2 Multipath Performance without Flat Fading: Eb/No K. Halford, S. Halford and M. Webster

5.3.2 Multipath Performance without Flat Fading: SNR November 2000 5.3.2 Multipath Performance without Flat Fading: SNR K. Halford, S. Halford and M. Webster

5.3.3: Multipath Sweeps: 1% to 10% November 2000 5.3.3: Multipath Sweeps: 1% to 10% Comparison Item 24 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. Answer: 0.0 nSeconds for all rates Why ? K. Halford, S. Halford and M. Webster

5.3.3 Multipath Sweeps: 1% to 10% November 2000 5.3.3 Multipath Sweeps: 1% to 10% PER Curves are very steep -- about 2 dB separates the 1% from the 10 % point K. Halford, S. Halford and M. Webster

5.3.3 Multipath Sweeps: 1% to 10% November 2000 5.3.3 Multipath Sweeps: 1% to 10% Rayleigh fading causes frequent swings to low SNR level K. Halford, S. Halford and M. Webster

5.3.3 Multipath Sweeps: 1% to 10% November 2000 5.3.3 Multipath Sweeps: 1% to 10% What we ran in place of Comparison Item 24 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. K. Halford, S. Halford and M. Webster

5.3.3 Multipath Performance: PER sweeps from 1% to 10% November 2000 5.3.3 Multipath Performance: PER sweeps from 1% to 10% K. Halford, S. Halford and M. Webster

5.4 Throughput Performance November 2000 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 K. Halford, S. Halford and M. Webster

5.4.1 Preamble Structures: Long and Short Preambles November 2000 5.4.1 Preamble Structures: Long and Short Preambles 802.11 HRb LONG PREAMBLE Signal Extension OFDM SYNC PSDU SELECTABLE OFDM Symbols @ 6.6, 9.6, 13.2, 19.8, 26.4, 39.3, 52.8 or 59.4 Mbps PREAMBLE/HEADER 192 usecs 10.9 usecs ~6 usecs Data Payload 802.11 HRb SHORT PREAMBLE Signal Extension PREAM/HDR 72 BITS @ 1 Mbps OFDM SYNC PSDU SELECTABLE OFDM Symbols @ 6.6, 9.6, 13.2, 19.8, 26.4, 39.3, 52.8 or 59.4 Mbps ~6 usecs 96 usecs 10.9 usecs K. Halford, S. Halford and M. Webster

5.4.1 Preamble Structures: Ultra-Short Preamble November 2000 5.4.1 Preamble Structures: Ultra-Short Preamble Proposed Ultra-Short Preamble Signal Extension Data Rate # bytes of data Data Payload 12 Short Syncs Rep’s Long SYNC PSDU SELECTABLE @ 6.6, 9.9, 13.2, 19.8, 26.4, 39.6, 52.8 or 59.4 Mbps SIGNAL SYMBOL 16 usecs 3.6 usecs ~6 usecs K. Halford, S. Halford and M. Webster

5.4.2 ACK Assumptions 1) No RTS/CTS OR MPDU < RTS_Threshold: November 2000 5.4.2 ACK Assumptions 1) No RTS/CTS OR MPDU < RTS_Threshold: Many different scenarios, but the constant is: {MPDU, SIFS, ACK} source DIFS Data destination SIFS ACK 2) RTS/CTS and/or MPDU > RTS_Threshold: source DIFS RTS SIFS Data destination SIFS CTS SIFS ACK 3) Middle of Fragmented Transmission: source SIFS Fragment 1 destination SIFS ACK 1 K. Halford, S. Halford and M. Webster

5.4.2 ACK Assumptions (continued) November 2000 5.4.2 ACK Assumptions (continued) 112 Bits @ 6.6 Mbps = 20 usec SIFS PSDU SELECTABLE OFDM Symbols @ 6.6, 9.6, 13.2, 19.8, 26.4, 39.3, 52.8 or 59.4 Mbps Packet Header Packet Header ACK OFDM PAD ~6 usecs K. Halford, S. Halford and M. Webster

5.4.3.1 Throughput for 100 Byte Packets November 2000 5.4.3.1 Throughput for 100 Byte Packets K. Halford, S. Halford and M. Webster

5.4.3.1 Throughput for 1000 Byte Packets November 2000 5.4.3.1 Throughput for 1000 Byte Packets K. Halford, S. Halford and M. Webster

5.4.3.1 Throughput for 2346 Byte Packets November 2000 5.4.3.1 Throughput for 2346 Byte Packets K. Halford, S. Halford and M. Webster

5.4.3.2 Throughput with ACK November 2000 K. Halford, S. Halford and M. Webster

5.4.3.2 Throughput without ACK November 2000 5.4.3.2 Throughput without ACK K. Halford, S. Halford and M. Webster

5.4.4 Comparison of Throughput for Variable Overhead for 100 Byte MPDU November 2000 5.4.4 Comparison of Throughput for Variable Overhead for 100 Byte MPDU K. Halford, S. Halford and M. Webster

November 2000 5.4.4 Comparison of Throughput for Variable Overhead for 1000 Byte MPDU K. Halford, S. Halford and M. Webster

November 2000 5.4.4 Comparison of Throughput for Variable Overhead for 2346 Byte MPDU K. Halford, S. Halford and M. Webster

5.4.5 Aggregate Throughputs for 2.4 GHz November 2000 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 K. Halford, S. Halford and M. Webster

5.5 CW Jammer Test Description November 2000 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: K. Halford, S. Halford and M. Webster

5.5 Performance Against CW Jammer November 2000 5.5 Performance Against CW Jammer Gp = (S/N)0 + Mj + Lsys K. Halford, S. Halford and M. Webster