1. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 1 A “High Throughput” Partial Proposal Patrik Eriksson, Anders Edman, Christian Kark Wavebreaker AB, Norrkoping, Sweden patrik.eriksson@acreo.se Scott Leyonhjelm, Mike Faulkner, Melvyn Pereira,Jason Gao, Aaron Reid,Tan Ying,Vasantha Crabb. Australian Telecommunication Co-operative Research Centre, Melbourne, Australia. scott.leyonhjelm@vu.edu.au

2. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 2 Presentation Outline Proposal Executive Summary Proposed Frame Format Proposed PHY Design Comparison Criteria Conclusion

3. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 3 Proposal Executive Summary Fully backward compatible with 802.11a/g –All enhancements are simple extensions to 11a/g OFDM structure. –STS and LTS sequences are used in conjunction with progressive cyclic delay per antenna Higher Data Throughput due to combination of PHY technologies –MIMO-OFDM - Spatial Multiplexing, up to 3 transmit spatial streams (mandatory), 4 spatial streams (optional) –Fast Rate adaptation on a per stream (mandatory) or a per subgroup (optional) level –Higher order modulation - 256QAM (mandatory) Higher Data Throughput due to combination of MAC enhancements –Frames with NO short and long training sequences (mandatory) –Frame aggregation (mandatory) –Shorter SIFS, down to 8 us. (Optional) Minimising Hardware Complexity –Frame format designed to increase available time for inverting channel estimate.

4. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 4 Presentation Outline Proposal Executive Summary Proposed Frame Format Proposed PHY Design Comparison Criteria Conclusion

5. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 5 Proposed Frame Format 3 new MIMO frame types are proposed: MIMO - Type 1 frames with Training. –Re-Synchronisation –Note that the STS, LTS and Sig2 sequence can be received by legacy equipment. –S3 is positioned to increase time allowed for calculating and inverting channel estimate MIMO - Type 2 frames without Training. –Preferred for Data carrying frames MIMO – Type 3 frames with Training. –RTS/CTS frames in 5GHz band –Note that the STS, LTS and Sig and Data sequence can be received by legacy equipment. –S3 is positioned to increase time allowed for calculating and inverting channel estimate

6. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 6 Proposed Frame Format 802.11a compatible Sig2LTS1aLTS1bLTS1c Sig2LTS2aLTS2bLTS2c Sig2 LTS3aLTS3bLTS3c Sig2LTS4aLTS4bLTS4c Sig3 D1 D2 STS1 LTS1Sig STS2 LTS2Sig STS3 LTS3Sig STS4 LTS4Sig D1 D2 Dn MIMO part of frame Length field faked Sig symbol MIMO data length Sig2 Symbol - Specify MIMO transmission Mode Adaptive Loading Mode MIMO mode Indicate if Sig3 and Data symbols are present Sig3 Symbol – supports MIMO transmission Reverse link CSI info Data Rate used in transmission Data length Request for retraining R4 – indicates MIMO Extra time for inverting CE Type 2 MIMO Frame (DATA)

7. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 7 Proposed Frame Format Type3 AP: STA: Type3 Type2 Type1 Time Type1 Type2 Training required for initially establishing fast rate adaptation Data carrying with no Training sequence Request for Training sequence Used for Re-transmission Re-synchronising during a RTS/CTS transmission, and Extending the duration of the transmission (CTS to self) Example of RTS/CTS frame transfer: RTS CTS Data ACK DataTraining n*4 us SIFS= 8-16us Updated rate information

8. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 8 Proposed Frame Format Proposed frame format compared to 802.11a –MAC Efficiency 61% vs 47% –PSDU Size = 1.5kbyte Frame Aggregation –9kbyte PSDU size –MAC efficiency >80%

9. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 9 Proposed Frame Format To Achieve Goodput of >100Mbps for PER 10%, PHY average rate =144Mbps Single Frame Transmission Mode –PSDU Size = 5kbyte packet RTS/CTS Transmission Mode –Packet Size > 2kbyte –Transmission Length = 10kbyte Frame Aggregation –Increases MAC efficiency –Proposed max. PSDU 16kbyte

10. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 10 Proposed Frame Format Implementation Details of the Frame Format proposal Channel Models in 802.11n are slowly moving (low Doppler) –Channel sufficiently stable for at least 50 symbols (MSE <-35dB) –Channel F with 40kph Doppler Component Type 2 packets have NO training sequences –Initial STS/LTS sets up Timing grid –Transmissions start at 4us intervals –Receiver uses fast power detection algorithms to determine if packet (sig3 symbol) is present or not –Frequency offset and sampling time offsets must flywheel over non- transmission periods Implementation Requirements –Time, frequency offsets tracked via 4 pilots –Channel Tracking

11. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 11 Presentation Outline Proposal Executive Summary Proposed Frame Format Proposed PHY Design Comparison Criteria Conclusion

12. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 12 Proposed PHY Design Parallel Spatial Multiplexing Architecture Scalable architecture - supports up to 3 (mandatory) or 4 (optional) antennas The mapping function expanded to include 256QAM Cyclic Delay is implemented with a progressive 1 sample delay /per antenna Fast Rate Adaptation DemuxDemux Data Bits Scramble Encode Punct Inter.Map Inter. FFTCP Cyclic Delay To DACs MapFFTCP Cyclic Delay MapFFTCP Cyclic Delay MapFFTCP Cyclic Delay Adaptive Loading Info from Sig3 Symbol ‘CSI’ field MuxMux STS and LTS Preambles MuxMux Pilots

13. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 13 Proposed PHY Design Fast Rate Adaptation Concept => Higher Average Data Throughput Based on Closed loop feedback of CSI transported by ACK frame Optimises Data rate to channel condition on a per packet basis Low implementation cost vs High performance gain Small impact on MAC efficiency –4 bits per spatial stream Overcomes spatial multiplexing singularity in LOS conditions –Naturally falls back to transmission of a single stream

14. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 14 Proposed PHY Design Rate Adaptation Concept –The STA determines the maximum rate per layer (mandatory) or subgroup of carriers (optional) and this is communicated back to the AP, and vice-versa. –Adaptive rate can vary from 0Mbit/s through to 72Mbits/s on a per layer basis. –Fast Adaptation handled at PHY layer, reported to MAC Punct/ Map Data Bits Tx Channel Estimation Rx Data Bits Forward Link SNR (Link Margin/layer) Calculate Maximum Rate Possible on a per layer basis Decode Sig3 Symbol ‘Rev CSI’ field Reverse Link Encode Sig3 Symbol ‘Rev CSI’ field

15. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 15 Proposed PHY Design Short Training Sequences –802.11a STS transmitted on each stream –Cyclic delay ensures good performance characteristics for AGC function Long Training Sequences –Based on current LTS definitions –Orthogonality between TX antennas achieved via Cyclic Delay and ‘Phase Loading’ –Channel Estimation achieved by combining received LTS’s TX1 TX2 TX3 STSLTS STSLTS LTS*exp (j  /3)LTS*exp (j2  /3) STSLTS LTS*exp (j2  /3)LTS*exp (j  /3)

16. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 16 Proposed PHY Design For >100 Mbps Goodput @ 10m: 3 data streams required For >3*3 MIMO : Channel estimation and equalisation begins to dominate Analog increases slightly less than linear due to reuse of functions

17. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 17 Presentation Outline Proposal Executive Summary Proposed Frame Format Proposed PHY Design Comparison Criteria Conclusion

18. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 18 Comparison Criteria –CC58 RTS/CTS frame transmission mode achieves a goodput of more than 100Mbps, The single frame transmission mode achieves a maximum goodput of 80Mbps when the average PHY data rate is 288Mbps !. To get >100Mbps –With frame aggregation a 5.5kbyte packet size transmitted at a average PHY data rate of 144Mbps –With channel bonding (optional) the average PHY data rate is increased by a factor 1.8 Just! with no impairments

19. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 19 Comparison Criteria CC59 –AWGN Channel –Observation : the capacity is a linear function of the number of transmit data streams.

20. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 20 Comparison criteria CC80- The modifications required for a legacy 802.11 PHY are; –The scalable architecture supports up to 3 (mandatory) or 4 (optional) antennas –Rate adaptation modifies the puncturing and Constellation Mapping on a stream basis, –Include 256 QAM –Cyclic Delay implemented with a progressive 1 sample delay /per antenna –The LTS preambles are modified versions of the 802.11a/g defined sequences

21. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 21 Presentation Outline Proposal Executive Summary Proposed Frame Format Proposed PHY Design Comparison Criteria Conclusion

22. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 22 Conclusion – Key Features Higher Data Throughput due to combination of PHY technologies –MIMO-OFDM – 1 to 3 data streams using Spatial Multiplexing –Rate Adaptation –Higher order modulation – 256QAM Higher Data Throughput due to combination of MAC enhancements –Frames with NO training sequences –Frame aggregation – up to 16kbytes/packet

23. doc.: IEEE 802.11-04/0929r1 Submission August 2004 Patrik Eriksson et. al., WaveBreaker ABSlide 23 Conclusion Backward Compatibility is ensured by –Operation within a 20MHz bandwidth with the same 802.11a/g spectral mask. –Single and RTS/CTS frame transmission modes are fully compatible with legacy 802.11a/g devices. All Low Functional Requirements are met Low Overhead Frame formats to increase MAC efficiency 100Mbps Goodput @ 10m achieved when –20MHz and >=3 transmit data streams –> 144Mbps Average PHY data rate –With Rate Adaptation!