1. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 1 WWiSE IEEE 802.11n Proposal August 13, 2004 Airgo Networks, Bermai, Broadcom, Conexant, STMicroelectronics, Texas Instruments

2. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 2 Contributors and contact information Airgo Networks: VK Jones, vkjones@airgonetworks.com Bermai: Neil Hamady, nhamady@bermai.com Broadcom: Jason Trachewsky, jat@broadcom.com Conexant: Michael Seals, michael.seals@conexant.com STMicroelectronics: George Vlantis, George.Vlantis@st.com Texas Instruments: Sean Coffey, coffey@ti.com

3. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 3 Contents WWiSE approach Overview of key features Proposal description –Physical layer design –MAC features Discussion Summary

4. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 4 The WWiSE approach WWiSE = World Wide Spectrum Efficiency The partnership was formed to develop a specification for next generation WLAN technology suitable for worldwide deployment Mandatory modes of the WWiSE proposal comply with current requirements in all major regulatory domains: Europe, Asia, Americas Proposal design emphasizes compatibility with existing installed base, building on experience with interoperability in 802.11g and previous 802.11 amendments All modes are compatible with QoS and 802.11e Maximal spectral efficiency translates to highest performance and throughput in all modes

5. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 5 Overview of key mandatory features The WWiSE proposal’s mandatory modes are: –2 transmit antennas –20 MHz operation –135 Mbps maximum PHY rate –2x1 transmit diversity modes –Mixed mode preambles enabling on-the-air legacy compatibility –Efficient greenfield preambles – no increase in length over legacy –Enhanced efficiency MAC mechanisms –All components based on enhancement of existing COFDM PHY 2x2 MIMO operation in a 20 MHz channel: Goal is a robust, efficient, small-form-factor, universally compliant 100 Mbps mode that fits naturally with the existing installed base

6. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 6 Overview of key optional features The WWiSE proposal’s optional modes are: –3 and 4 transmit antennas –40 MHz operation –Up to 540 Mbps PHY rate –3x2, 4x2, 4x3 transmit diversity modes –Advanced coding: Rate-compatible LDPC code All modes are open-loop

7. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 7 Physical layer design Data modes –Transmitter structure –PHY rates –MIMO interleaving Preambles –Short sequences –Long sequences –SIGNAL fields

8. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 8 Transmitter block diagram FEC encoder, puncturer MIMO interleaver Symbol mapper D/A Interpol., filtering, limiter Upconverter, amplifier IFFT Add cyclic extension (guard) Add pilots Insert training

9. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 9 Mandatory data modes 2 transmitter space-division multiplexing, 20 MHz 2 transmitter space-time transmit diversity, 20 MHz 802.11a/g (OFDM) modes 64-state BCC

10. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 10 2 transmitter SDM, 20 MHz (mandatory) PHY rateData carriers PilotsCode rate Cyclic prefix, ns CodeConstellation 54 Mbps5421/2800BCC16-QAM 81 Mbps5423/4800BCC16-QAM 108 Mbps5422/3800BCC64-QAM 121.5 Mbps5423/4800BCC64-QAM 135 Mbps5425/6800BCC64-QAM

11. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 11 2x1 modes, 20 MHz (mandatory) PHY rateData carriers PilotsCode rate Cyclic prefix, ns CodeConstellation 6.75 Mbps5421/2800BCCBPSK 10.125 Mbps5423/4800BCCBPSK 13.5 Mbps5421/2800BCCQPSK 20.25 Mbps5423/4800BCCQPSK 27 Mbps5421/2800BCC16-QAM 40.5 Mbps5423/4800BCC16-QAM 54 Mbps5422/3800BCC64-QAM 60.75 Mbps5423/4800BCC64-QAM

12. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 12 Optional data modes 20 MHz: –3 Tx space-division multiplexing –4 Tx space division multiplexing –3x2, 4x2, 4x3 space-time transmit diversity 40 MHz: (all 40 MHz modes optional) –1 Tx antenna –2 Tx space division multiplexing –3 Tx space division multiplexing –4 Tx space division multiplexing –2x1, 3x2, 4x2, 4x3 space-time transmit diversity LDPC code option –An option in all proposed MIMO configurations and channel bandwidths

13. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 13 Optional modes, common format Code rate Cyclic prefix, ns CodeConstellation 1/2800BCC, LDPC16-QAM 3/4800BCC, LDPC16-QAM 2/3800BCC, LDPC64-QAM 3/4800BCC, LDPC64-QAM 5/6800BCC, LDPC64-QAM All combinations of 2, 3, 4 transmit antennas and 20/40 MHz offer exactly these 5 modes All 20 MHz modes have 54 data subcarriers, 2 pilots. All 40 MHz modes have 108 data subcarriers, 4 pilots

14. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 14 Optional mode data rates ConfigurationRate ½, 16-QAM Rate ¾, 16-QAM Rate 2/3, 64-QAM Rate ¾, 64-QAM Rate 5/6, 64-QAM 3 Tx, 20 MHz 81121.5162182.25202.5 4 Tx, 20 MHz 108162216243270 ConfigurationRate ½, 16-QAM Rate ¾, 16-QAM Rate 2/3, 64-QAM Rate ¾, 64-QAM Rate 5/6, 64-QAM 1 Tx, 40 MHz 5481108121.5135 2 Tx, 40 MHz 108162216243270 3 Tx, 40 MHz 162243324364.5405 4 Tx, 40 MHz 216364432486540 40 MHz: 20 MHz:

15. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 15 FEC encoder, puncturer MIMO interleaver Symbol mapper D/A Interpol., filtering, limiter Upconverter, amplifier IFFT Add cyclic extension (guard) Add pilots Insert training

16. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 16 Preambles Mixed-mode preambles: –Capable of operation in presence of legacy 11a/g devices –Ensure correct deferral behavior by devices compliant to legacy spec Green-field preambles: –Operate in environment or time interval with only 11n devices on the air –Applicable in combination with protection mechanisms, as in 11g, or in 11n-only BSSs –Greater efficiency than mixed-mode preambles Both preamble types are derived from a common basic structure, providing reuse in algorithms

17. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 17 Short training sequence STRN 400 ns cs STRN 400 ns cs STRN 200 ns cs STRN 400 ns cs STRN 200 ns cs STRN 600 ns cs 2 Transmitters 3 Transmitters 4 Transmitters 20 MHz: STRN = 802.11ag short training sequence 40 MHz mixed mode: STRN = Pair of 802.11ag short sequences separated in frequency by 20 MHz 40 MHz green field: STRN = Newly defined sequence cs = Cyclic shift

18. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 18 Long training sequence and SIGNAL-N, green-field, 2 transmitters 20 MHz: LTRN = 802.11ag long training sequence with four extra tones, 6.4 usec 40 MHz: LTRN = Newly defined sequence, 6.4 usec GI2 1 = GI2 for LTRN with 1600 ns cyclic shift SIGNAL-N = 54 bits, 4 usec GI2 1 STRN 400 ns cs LTRN 1600 ns cs GI2 SIGNAL-N 1600 ns cs

19. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 19 Long training sequence and SIGNAL-N, green-field, 3 and 4 transmitters STRN 400 ns cs STRN 200 ns cs STRN 600 ns cs GI2 1 LTRN 1600 ns cs GI2 GI2 3 LTRN 100 ns cs LTRN 1700 ns cs GI2 2 GI2 1 LTRN 1600 ns cs GI2  GI2 3  LTRN 100 ns cs  LTRN 1700 ns cs  GI2 2 SIGNAL-N 100 ns cs SIGNAL-N 1600 ns cs SIGNAL-N 1700 ns cs For 3 transmitters, the first three rows are used

20. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 20 Long training and SIGNAL fields, mixed mode, 2 transmitters GI2 4 STRN 400 ns cs LTRN  100 ns cs GI2 SIGNAL  100 ns cs 2 transmitter green-field long training and SIGNAL-N; plus short sequence if 40 MHz

21. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 21 Long training and SIGNAL fields, mixed mode, 3 and 4 transmitters STRN LTRN STRN 400 ns cs GI2 4 LTRN  100 ns cs GI2 SIGNAL  100 ns cs 3 or 4 transmitter green-field long training and SIGNAL-N; plus short training if 40 MHz STRN 600 ns cs SIGNAL 200 ns cs GI2 6 LTRN 200 ns cs STRN 200 ns cs LTRN 100 ns cs GI2 5 SIGNAL 100 ns cs For 3 transmitters, the first three rows are used

22. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 22 Preamble lengths (20 & 40 MHz) All space-time block codes follow the pattern with the same number of transmit antennas 8 8 0 0 Second long 284884x4 284883x3 204882x2 204881x1 TotalSIGNALFirst long ShortConfigurationGreen-field

23. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 23 Preamble lengths (20 & 40 MHz), contd. All space-time block codes follow the pattern with the same number of transmit antennas Mixed mode 0/8  /8 Second short 8 8 0 0 Third long 4 4 4 4 Second SIGNAL 8 8 8 8 Second long 40/484884x4 40/484883x3 32/404882x2  /40 4881x1 TotalSIGNALFirst long ShortConfiguration

24. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 24 FEC encoder, puncturer MIMO interleaver Symbol mapper D/A Interpol., filtering, limiter Upconverter, amplifier IFFT Add cyclic extension (guard) Add pilots Insert training

25. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 25 Parallel encoders For 40 MHz modes with more than two spatial streams, two parallel BCC encoders are used: Multiplexing across two encoders (round robin) BCC encoder, puncturer To MIMO interleaver Data payload

26. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 26 Advanced coding option Rate-compatible LDPC code with the following parameters: Transmitter block diagram as for BCC modes, except symbol interleaver, rate-compatible puncturing, and tail bits are not used 194416205/6 194414583/4 194412962/3 19449721/2 Block lengthInformation bitsRate

27. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 27 LDPC code, contd. There is no change required to SIFS or to any other system timing parameters when the advanced coding option is used The block size of 1944 reduces or eliminates the need for pad bits at the end of a packet –Pad bits are eliminated for 2 transmitter operation in 20 MHz channels, and 2x1 and 1x1 in 40 MHz channels The four parity check matrices are derived from the rate-1/2 matrix via row combining The parity check matrices are structured and based on square- shaped building blocks of size 27x27 The parity check matrices are structured to enable efficient encoding

28. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 28 FEC encoder, puncturer MIMO interleaver Symbol mapper D/A Interpol., filtering, limiter Upconverter, amplifier IFFT Add cyclic extension (guard) Add pilots Insert training

29. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 29 MIMO interleaving Coded bits TX 0 interleaved bits TX 1 interleaved bits ConfigurationIdepth 108 tones, 1 Tx, 2x112 All others6 Bit-cycling across N TX transmitters Parameterized 802.11a-style interleaver 5 subcarrier shift, same interleaver... Shift of 5 additional subcarriers for each additional antenna

30. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 30 FEC encoder, puncturer MIMO interleaver Symbol mapper D/A Interpol., filtering, limiter Upconverter, amplifier IFFT Add cyclic extension (guard) Add pilots Insert training

31. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 31 Space-time block codes and asymmetry Simple space-time block codes (STBCs) are used to handle asymmetric antenna configurations –STBC rate always is an integer  No new PHY rates result from STBC encoding of streams –Block size is always two OFDM symbols –STBC encoding follows the stream encoding AP STA

32. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 32 Space-time block codes 2x1: 3x2: 4x2: 4x3: s1*s1* s2*s2* Tx 2 s2s2 s1s1 Tx 1 t2t2 t1t1 s1*s1* s2*s2* Tx 2 s4s4 s3s3 Tx 3 s2s2 s1s1 Tx 1 t2t2 t1t1 s1*s1* s2*s2* Tx 2 s4s4 s3s3 Tx 3 s3*s3* s4*s4* Tx 4 s2s2 s1s1 Tx 1 t2t2 t1t1 s1*s1* s2*s2* Tx 2 s4s4 s3s3 Tx 3 ss ss Tx 4 s2s2 s1s1 Tx 1 t2t2 t1t1 The STBC is applied independently to each OFDM subcarrier

33. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 33 FEC encoder, puncturer MIMO interleaver Symbol mapper D/A Interpol., filtering, limiter Upconverter, amplifier IFFT Add cyclic extension (guard) Add pilots Insert training

34. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 34 Power spectral density, 20 MHz

35. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 35 Power spectral density, 40 MHz

36. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 36 MAC features

37. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 37 New MAC features The WWiSE proposal builds on 802.11e functionality as much as possible, in particular EDCA, HCCA, and Block Ack –Goal is backward compatibility and simplicity –Block Ack is mandatory in the proposal Bursting and Aggregation: –MSDU aggregation –PSDU aggregation –Increased maximum PSDU length, to 8191 octets –HTP burst: sequence of MPDUs from same transmitter, separated by zero interframe spacing (if at same Tx power level and PHY configuration) or 2 usec (otherwise)

38. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 38 New MAC features, contd. Block Ack frames ACK policy –Reduce Block Ack overhead –Allows multiple RA + Block Ack Frames within a single HTP burst Legacy remediation –N-STA detection/advertisement Identification of TGn and non-TGn devices and BSSs –Legacy Protection mechanisms Additions to existing protection mechanisms –40/20 MHz channel switching Equitable sharing of resources with legacy

39. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 39 EDCA Simulation Results EDCA 2x2 – 20MHz 5GHz (max rate = 135 mbps) –QOS goals met, all flows, all scenarios S-1: 54 Mbps (52q/1.5nq), latencies excellent S-4: 44 Mbps (10q/34nq), latencies excellent S-6: 47 Mbps (45q/2nq), latencies very good EDCA 2x2 – 40MHz 5GHz (max rate = 270 mbps) –Even better, e.g. S-1: 56 Mbps (52q/3.5nq), latencies excellent S-4: 65 Mbps (10q/55nq), latencies excellent S-6: 51 Mbps (45q/6nq), latencies excellent * HTP burst employed in sims, but no aggregation used

40. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 40 EDCA Simulation Parameters – AP/STA e.g. scenario 4 CWMINCWMAXAIFSN TXOP LIMIT msec AC_BK31/63511/5114/42.0/1.0 AC_BE31/63127/2554/43.0/2.5 AC_VI15/1531/313/32.5/1.1 AC_VO7/1531/312/21.2/1.0

41. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 41 HCCA Simulation Results HCCA 2x2 – 20MHz 5GHz (max rate = 135 mbps) –QOS goals met, all flows, all scenarios S-1: 80 Mbps (52q/28nq), latencies excellent S-4: 86 Mbps (10q/76nq), latencies very good* S-6: 63 Mbps (45q/18nq), latencies excellent HCCA 2x2 – 40MHz 5GHz (max rate = 270 mbps) –Even better, e.g. S-1: 110 Mbps (52q/58nq), latencies excellent S-4: 135 Mbps (10q/125nq), latencies excellent S-6: 70 Mbps (46q/24nq), latencies excellent * scheduler tuned too much toward BE flows

42. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 42 HCCA Simulation Parameters HTP burst employed, but no aggregation used Very simple scheduler –Round robin Same TXOP value granted to all STA, regardless of flow characteristics, number of flows at STA, or priority of flows Each STA polled once per round No real effort put into making an intelligent scheduler Results quite good –Could be better, if more effort was applied

43. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 43 Discussion

44. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 44 100 Mbps throughput See response to CC 27 in 11/04-0877-00-000n Efficiency upgrades in 802.11e and further enhancements in 11n mean that the 45-50% system efficiencies of old 802.11 systems have evolved to 75-85% in contemporary systems –Many such enhancements are commercially available in firmware upgrades from multiple vendors 100 Mbps throughput is achieved from 135 Mbps PHY rate in a variety of setups –Both EDCA and HCCA allow this efficiency 100 Mbps throughput may even be achieved from 121.5 Mbps PHY rate –This requires HCCA; EDCA does not suffice

45. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 45 100 Mbps throughput, contd. Example scenario: –4000 byte packets –HTP burst transmission, 3 packets –Block ack –10%+ for assorted other users, beacons, etc. BSS share, etc. Preamble SIGNAL-N SIFSDIFS 960 usec Data payload Block ack request/ack 20240 4 4 24 1632 34 106

46. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 46 Robustness of modes 2x2 operation achieving 100 Mbps throughput in a 20 MHz channel is feasible –Requires high-performance signal processing –At highest rates, high performance MIMO detection and/or advanced coding are required 2x3 operation achieving 100 Mbps throughput in a 20 MHz channel is very feasible –Achieves throughput targets with MMSE processing and BCC Balance and approach are up to the implementer and beyond the scope of the standard

47. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 47 Capacity and operating points, 2x2 Channel model D, NLOS, half-wavelength spacing Curves are envelopes of curves for the 5 rates For each constituent curve, capacity is reduced by outage Baseline 108 is a 2 Tx system with 802.11a/g 54 Mbps

48. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 48 Optionality of 40 MHz Reasons why 40 MHz channels are not proposed as mandatory: Limited worldwide applicability –Europe: clause 4.4.2.2 of ETSI EN 301 893 V1.2.3 –Japan: ARIB STD-T71 The repackaging effect: –Halving the number of channels to provide each twice the data rate is of questionable value as an enhancement System and contention overhead: –Double the number of users in a single BSS results in increased contention losses; two separate 20 MHz channels generally provide better network capacity, especially with coordinated management Backward compatibility and interoperability: –In dense legacy network deployments, contiguous 40 MHz transmission bandwidth may not be available or performance may be impaired

49. Submission August 2004 doc.: IEEE 802.11-04/0935r1 S. Coffey, et al., WWiSE group Slide 49 References 1.IEEE 802.11/04-0886-00-000n, “WWiSE group PHY and MAC specification,” M. Singh, B. Edwards et al. 2.IEEE 802.11/04-0877-00-000n, “WWiSE proposal response to functional requirements and comparison criteria,” C. Hansen et al.