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Response to Call For Proposal for P802.11n

Response to Call For Proposal for P802.11n. Hervé Bonneville, Bruno Jechoux, Romain Rollet Mitsubishi ITE 1, allee de Beaulieu, 35700 Rennes, France e-Mail: {bonneville,jechoux}@tcl.ite.mee.com

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Response to Call For Proposal for P802.11n

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  1. Response to Call For Proposal for P802.11n • Hervé Bonneville, Bruno Jechoux, Romain Rollet • Mitsubishi ITE1, allee de Beaulieu, 35700 Rennes, Francee-Mail: {bonneville,jechoux}@tcl.ite.mee.com Alexandre Ribeiro Dias, Stéphanie Rouquette-Léveil, Markus Muck, Marc de Courville, Jean-Noël Patillon, Karine Gosse, Brian Classon Motorola Labs Parc les Algorithmes – Saint Aubin – 91193 Gif sur Yvette Cedex - France e-Mail: {ribeiro,rouquet,muck,courvill,patillon}@crm.mot.com Bonneville,Patillon Mitsubishi/Motorola

  2. Mitsubishi ITE - Motorola Joint ProposalBackground • Complete proposal resulting from a joint effort of Mitsubishi Electric ITE and Motorola to make 802.11n the system of choice for Consumer Electronics market while enhancing the service for 802.11 PC/enterprise historical market. • Goal is to provide an efficient MAC handling of QoS sensitive applications taking full benefit of a high throughput MIMO based PHY while keeping compatibility with legacy systems • Various environments supported • Enterprise • Home environment • Hot Spot • Proven and simple solutions Bonneville,Patillon Mitsubishi/Motorola

  3. Content • Proposal Guide and Overview • PHY Description • Link Performance • MAC Description • System Performance Bonneville,Patillon Mitsubishi/Motorola

  4. Guide to Mitsubishi ITE -MotorolaProposal The complete proposal submitted by MITSUBISHI ITE and MOTOROLA consists of the following four documents: • 11-04-0914-02-000n- mitsubishi-ite-motorola-proposal-response • Response to functional requirements, comparison criteria table. Includes also a technical overview • 11-04-0915-02-000n-mitsubishi-ite-motorola-proposal-detaileddescription • Detailed technical description of the proposal • 11-04-0916-02-000n-mitsubishi-ite-motorola-proposal-presentation • this document • 11-04-0986-01-000n-mitsubishi-ite-motorola-proposal-simresults • Detailed system simulation results (Excel spread sheet) Bonneville,Patillon Mitsubishi/Motorola

  5. Overall goal of the proposed PHY design Modification of IEEE 802.11a-1999 PHY in order to provide new OFDM PHY modes meeting the IEEE802.11n PAR with: • High spectrum efficiency for achieving target performance with increased data rates • Data streams transmitted in parallel using multi-antenna transceivers • Optimized multi-carrier modulation with lower overhead • Enhanced forward error correction schemes • Improved link budget for lower to medium data rates • Providing the IEEE802.11a PHY data rates with increased range/link quality • Adapted to the support of services requiring small packet size such as VoIP • Exploit multi-antenna capabilities for robust transmission modes • Turn gains in spectral efficiency into link budget advantages • Favored short term implementation and deployment with robust, low complexity techniques • Open-loop multi-antenna solutions: simple, robust and without protocol overhead (feedback signalization) • Improve operation in limited Outdoor environments with support of long channel impulse responses Bonneville,Patillon Mitsubishi/Motorola

  6. Key features of the PHY • Multi-antenna extension (mandatory): • MIMO with at least 2Tx/2Rx antennas scaling up to 4Tx combined with combination of Space Division Multiplexing and Space Time Block Coding • Support for asymmetric antenna configurations to accommodate various classes of devices (laptop/phone/PDA) • Open-loop modulation technique to avoid protocol overhead consumed in feedback signalization • Second OFDM modulator (optional): 128 carriers in with 104 data carriers, and double duration guard interval • Provide PHY rate increase of 8% for 20MHz • Operate in larger environments, take better into account Tx/Rx filters due to increased guard interval length • New nPLCP preambles (same for 64- and 128-point IFFT/FFT) for MIMO support • Plus: • High order modulation (optional): 256-QAM • 20MHz bandwidth mandatory • Space/frequency interleaver • IEEE 802.11a convolutional code with code rates 1/2, 2/3, 3/4 and 5/6 Bonneville,Patillon Mitsubishi/Motorola

  7. Proposal Overview: MAC • Full compatibility with legacy 802.11 stations • QoS support with guarantied throughput and stringent delay constraints support even in heavily loaded system • Centralised on demand resource allocation with Resource announcement, • efficient even with simple per priority Round Robin scheduler • TDMA mode embedded in 802.11e superframe • Resource request/grant scheme for allocation in UL • Aggregation at PHY level (1 to several destination) • Fast selective repeat ARQ for low latency and low overhead error correction Bonneville,Patillon Mitsubishi/Motorola

  8. Proposal Overview: MAC(Continued) • Short and fixed size MAC-PDU with MAC Header compression • Flexible architecture for efficient handling of heterogeneous traffics (Bursty, CBR, Elastic) • Support of multiple environments without context-dependent parameter tuning • High efficiency and Scalable architecture (constant overhead when data rate increases) • Low complexity, low power consumption Bonneville,Patillon Mitsubishi/Motorola

  9. Typical system performances • All QoS flows satisfied • Scenario XVI: Use the most efficient PHY mode (3x3 256QAM3/4, Ns=3) (*) bis stands for: “with fully backlogged TCP sources” Bonneville,Patillon Mitsubishi/Motorola

  10. PHY Description Bonneville,Patillon Mitsubishi/Motorola

  11. PHY description: Multi-antenna scheme • Transmission of 1, 2 or 3 parallel streams using: • Space-Time Block Coding (STBC), Spatial Division Multiplexing (SDM) or robust hybrid solutions (STBC/SDM) • optimize the rate vs link budget trade-off • 2, 3 or 4 transmit antennas • The number of receive antennas determines the maximum number of spatial streams that can be transmitted. • The capability of decoding 2 parallel data streams is mandatory • all the devices have to be able to decode all the modes where the number of spatial streams is lower or equal than the number of receive antennas in the device. • It is required for a device to exploit all its antennas in transmission even for optional modes. • 2 or more receive antennas • With STBC or STBC/SDM, asymmetric antenna configurations can be supported • Importance of configurations in which NTx≠ NRx • NTx > NRx e.g. between AP and mobile handset (in DL) • NTx < NRx e.g. between MT and AP (UL), or if MT have upgraded multi-antenna capabilities compared to AP (infrastructure upgrade cost) Bonneville,Patillon Mitsubishi/Motorola

  12. 3 transmit antenna schemes proposed 2 transmit antenna schemes proposed 4 transmit antenna schemes proposed Bonneville,Patillon Mitsubishi/Motorola

  13. OFDM modulation • OFDM modulation based on IEEE802.11a parameters: • 48 data subcarriers, 64-point IFFT/FFT • 180Mbps maximum PHY rate (120Mbps mandatory) • 2nd OFDM modulation (optional extension): • 128-point IFFT/FFT • 104 data subcarriers, 8 pilots • Guard interval duration: 1.6s • Symbol interval: 6.4s • 234Mbps maximum PHY rate Bonneville,Patillon Mitsubishi/Motorola

  14. Data rate (Mbits/s) Data rate (Mbits/s) Number of spatial streams (NS) Number of spatial streams (NS) Modulation Modulation Coding rate (R) Coding rate (R) Coded bits per subcarrier per stream (NBPSC) Coded bits per subcarrier per stream (NBPSC) Coded bits/ symbol (NCBPS) Coded bits/ symbol (NCBPS) Data bits/ symbol (NDBPS) Data bits/ symbol (NDBPS) 6.5Mbps 1 BPSK 1/2 1 104 52 6Mbps 1 BPSK 1/2 1 48 24 13Mbps 1 QPSK 1/2 2 208 104 12Mbps 1 QPSK 1/2 2 96 48 19.5Mbps 1 QPSK 3/4 2 208 156 18Mbps 1 QPSK 3/4 2 96 72 24Mbps 1 16QAM 1/2 4 192 96 26Mbps 1 16QAM 1/2 4 416 208 36Mbps 1 16QAM 3/4 4 192 144 39Mbps 1 16QAM 3/4 4 416 312 48Mbps 1 64QAM 2/3 6 288 192 52Mbps 1 64QAM 2/3 6 624 416 60Mbps 1 64QAM 5/6 6 288 240 65Mbps 1 64QAM 5/6 6 624 520 72Mbps 2 16QAM 3/4 4 192 144 78Mbps 2 16QAM 3/4 4 416 312 96Mbps 2 64QAM 2/3 6 288 192 104Mbps 2 64QAM 2/3 6 624 416 108Mbps 2 64QAM 3/4 6 288 216 117Mbps 2 64QAM 3/4 6 624 468 120Mbps 2 64QAM 5/6 6 288 240 130Mbps 2 64QAM 5/6 6 624 520 144Mbps 2 256QAM 3/4 8 384 288 156Mbps 2 256QAM 3/4 8 832 624 Mode: 2-TX48 carriers Mode: 2-TX104 carriers Bonneville,Patillon Mitsubishi/Motorola

  15. Data rate (Mbits/s) Data rate (Mbits/s) Number of spatial streams (NS) Number of spatial streams (NS) Modulation Modulation Coding rate (R) Coding rate (R) Coded bits per subcarrier per stream (NBPSC) Coded bits per subcarrier per stream (NBPSC) Coded bits per OFDM symbol Coded bits per OFDM symbol Data bits per OFDM symbol Data bits per OFDM symbol 13Mbps 2 BPSK 1/2 1 104 52 12Mbps 2 BPSK 1/2 1 48 24 26Mbps 2 QPSK 1/2 2 208 104 24Mbps 2 QPSK 1/2 2 96 48 39Mbps 2 QPSK 3/4 2 208 156 36Mbps 2 QPSK 3/4 2 96 72 52Mbps 2 16QAM 1/2 4 416 208 48Mbps 2 16QAM 1/2 4 192 96 78Mbps 2 16QAM 3/4 4 416 312 72Mbps 2 16QAM 3/4 4 192 144 104Mbps 2 64QAM 2/3 6 624 416 96Mbps 2 64QAM 2/3 6 288 192 130Mbps 2 64QAM 5/6 6 624 520 120Mbps 2 64QAM 5/6 6 288 240 156Mbps 3 64QAM 2/3 6 624 416 144Mbps 3 64QAM 2/3 6 288 192 175.5Mbps 3 64QAM 3/4 6 624 468 162Mbps 3 64QAM 3/4 6 288 216 180Mbps 3 64QAM 5/6 6 288 240 195Mbps 3 64QAM 5/6 6 624 520 216Mbps 3 256QAM 3/4 8 384 288 234Mbps 3 256QAM 3/4 8 832 624 Mode: 3/4-TX48 carriers Mode: 3/4-TX104 carriers Bonneville,Patillon Mitsubishi/Motorola

  16. Frequency and space interleaver • IEEE802.11a based frequency interleaver defined for both 48 and 104 data subcarriers • Spatial division: • NSD : number of data subcarriers Bonneville,Patillon Mitsubishi/Motorola

  17. nPLCP preamble (I/2) Bonneville,Patillon Mitsubishi/Motorola

  18. nPLCP preamble (II/2) • Overview on different frame structures: Bonneville,Patillon Mitsubishi/Motorola

  19. Link Performance Bonneville,Patillon Mitsubishi/Motorola

  20. Simulation results • AWGN, TGnB, TGnD, TGnE channel comparisons for 20MHz Bandwidth • Essential points • Throughput increase with optional modes (FFT-128) at constant SNR requirements in AWGN channels • Robust modes based on STBC for good coverage and support of asymetric configurations • Unilateral modification of number of antennas in TX and RX can be exploited Useful for independent evolution of AP/MT Bonneville,Patillon Mitsubishi/Motorola

  21. Simulation results - AWGN • 2TX/2RX to 4TX/4RX configuration and SNR ~21dB:120Mbps  180Mbps (130Mbps  195Mbps)  Bonneville,Patillon Mitsubishi/Motorola

  22. Mode/ Mbps SNR for PER=10-1 180 XXX  42dB  34dB 120 36dB  28dB  24.5dB 96 32dB  24dB  21dB 48 20dB  16dB  14dB 12 10dB  7dB  6dB Simulation results - TGnB • Diversity gain for all streams • 120 Mbps lowers SNR ~ 36dB  28dB  24.5dB Bonneville,Patillon Mitsubishi/Motorola

  23. Simulation results - TGnB • For new schemes: Same behaviour is observed for diversity modes as for classical schemes • Clear improvements for 2 streams from 2x2  3x3 mode • Clear improvements for 3 streams from 2x2/3x3  4x4 mode Bonneville,Patillon Mitsubishi/Motorola

  24. Mode/Mbps Mode/Mbps SNR for PER=10-1 SNR for PER=10-1 120 120 31.5dB 26.5dB 96 96 24dB 28dB 48 48 16dB 20dB 12 12 5dB 11dB Simulation results - TGnB • # TX antennas < # RX antennas  e.g. Update of MT • # TX antennas > # RX antennas  e.g. Update of AP Bonneville,Patillon Mitsubishi/Motorola

  25. PHY Throughput Analysis – TGnB • Link adaptation is based on long term average SNR  sub-optimum  inferior bound • Finer grid possible with more modes Bonneville,Patillon Mitsubishi/Motorola

  26. Mode/ Mbps SNR for PER=10-1 180 (effect) XXX  36dB  29dB 180 XXX  36dB  29dB 120 35dB  25.5dB  23dB 96 27.5dB  21dB  19dB 48 18dB  14dB  11dB 12 5dB  4.5dB  3.5dB Simulation results - TGnD • Diversity gain for all streams • 120 Mbps lowers SNR ~ 35dB  25.5dB  23dB Bonneville,Patillon Mitsubishi/Motorola

  27. Mode/Mbps Mode/Mbps SNR for PER=10-1 SNR for PER=10-1 120 120 30dB 24dB 96 96 20dB 25.5dB 48 48 14.5dB 17dB 12 12 2dB 7dB Simulation results - TGnD • # TX antennas < # RX antennas  e.g. Update of MT • # TX antennas > # RX antennas  e.g. Update of AP Bonneville,Patillon Mitsubishi/Motorola

  28. Mode/ Mbps SNR for PER=10-1 180 XXX  43dB  31dB 120 37dB  26.5dB  24dB 96 30dB  22.5dB  20dB 48 19dB  15dB  12dB 12 7dB  5dB  4dB Simulation results - TGnE • Diversity gain for all streams • 120 Mbps lowers SNR ~ 37dB  26.5dB  24dB Bonneville,Patillon Mitsubishi/Motorola

  29. Mode/Mbps Mode/Mbps SNR for PER=10-1 SNR for PER=10-1 120 120 31.5dB 25dB 96 96 21.5dB 26.5dB 48 48 15dB 18dB 12 12 4dB 9dB Simulation results - TGnE • # TX antennas < # RX antennas  e.g. Update of MT • # TX antennas > # RX antennas  e.g. Update of AP Bonneville,Patillon Mitsubishi/Motorola

  30. Simulation results – TGnD/TGnE • Similar to TGnB: • 2Tx: • Diversity gain for 1 stream, but not for 2 streams • 120 Mbps requires SNR ~ 35dB (TGnD) 37dB (TGnE) • 3Tx: • Diversity gain for 2 streams, but not for 3 streams • 120 Mbps lowers SNR: • ~ 36dB  26dB (TGnD) • ~ 37dB  26.5dB (TGnE) • 4Tx: • Diversity gain for all streams • 120 Mbps lowers SNR • ~ 36dB  26dB  23dB (TGnD) • ~ 37dB  26.5dB  24dB (TGnD) Bonneville,Patillon Mitsubishi/Motorola

  31. Simulation results – Offset compensation • No significant impact at 10% PER in channel E (NLOS) Bonneville,Patillon Mitsubishi/Motorola Figure 42 - Offset impact in 4x4 antenna configuration

  32. Antenna configuration Data rate (Mbits/s) PER when carrier offset = -40ppm PER when carrier offset = 0ppm PER when carrier offset =+40ppm 2x2 12Mbps 0.0003 0.0003 0.0002 2x2 48Mbps 0.0016 0.0016 0.0018 2x2 96Mbps 0.0039 0.0037 0.0042 2x2 120Mbps 0.0297 0.0183 0.0298 Simulation results – Offset compensation • Impact of carrier frequency offset and symbol clock offset at SNR=50dB in channel E (LOS): • Small degradation of the PER performance • High data rate modes are more impacted: • PER (+40ppm) = 112/100xPER (0ppm) at 48Mbps • PER (+40ppm) = 163/100xPER (0ppm) at 120Mbps Bonneville,Patillon Mitsubishi/Motorola Figure 42 - Offset impact in 4x4 antenna configuration

  33. Antenna configuration Data rate (Mbits/s) PER when carrier offset = -40ppm PER when carrier offset = 0ppm PER when carrier offset =+40ppm Antenna configuration Data rate (Mbits/s) PER when carrier offset = -40ppm PER when carrier offset = 0ppm PER when carrier offset =+40ppm 3x3 12Mbps 0.0002 0.0001 ~0 4x4 12Mbps ~0 ~0 ~0 3x3 48Mbps 0.0006 0.0006 0.0005 4x4 48Mbps 0.0001 0.0001 0.0001 3x3 96Mbps 0.0041 0.0041 0.0043 4x4 96Mbps 0.0016 0.0016 0.0019 3x3 120Mbps 0.0043 0.0045 0.0050 4x4 120Mbps 0.0021 0.0021 0.0022 3x3 180Mbps 0.0963 0.0617 0.0974 4x4 180Mbps 0.0023 0.0024 0.0029 Simulation results – Offset compensation • High data rate modes are less impacted if spatial diversity: • 3x3: PER (+40ppm) = 158/100xPER (0ppm) at 180Mbps • 4x4: PER (+40ppm) = 121/100xPER (0ppm) at 180Mbps Bonneville,Patillon Mitsubishi/Motorola Figure 42 - Offset impact in 4x4 antenna configuration

  34. Implementation complexity Bonneville,Patillon Mitsubishi/Motorola

  35. Conclusion • Proposal: MIMO extension of IEEE802.11a addressing • Short term implementation needs through mandatory modes relying on a mix of STBC and SDM • Take into account device size constraints allowing asymmetric TX/TX antenna configuration independent upgrade of APs / MTs possible • Enable PHY throughput covering 54Mbits/s  180 (234) Mbps Bonneville,Patillon Mitsubishi/Motorola

  36. MAC Description Bonneville,Patillon Mitsubishi/Motorola

  37. Why a new access mode? • 802.11n scope: Enhance performance, properly serve QoS application and increase efficiency. • Identified weaknesses in legacy MAC: • Collisions and contention overhead (EDCA) • Fixed Inter Frame Spaces (All) • Polling efficiency and latency (HCCA) • MAC-PDU overhead (All) • PLCP overhead (All) • Block ACK limitations (All) • Numerous new patches to legacy required Bonneville,Patillon Mitsubishi/Motorola

  38. Why a new access mode?(cont’d) • Minimum set of modifications • Centralised on-demand resource allocation • Polling enhancement • New frame format • MAC PDUs and PLCP overhead reduction • Flexible and error-resistant frame aggregation • ARQ scheme • More powerful and more flexible than Block ACK • In-band, resource thrifty signaling • Latency reduction and efficiency increase • TDM frame • Collision and contention suppression • A new access mode is preferable Bonneville,Patillon Mitsubishi/Motorola

  39. MAC Design philosophy • Driving idea:Efficient even for Bursty and uncharacterised flows • Solution • TDMA with variable duration time interval (TI) allocation • Fast resource request/grant scheme • In-band signalling in already allocated TI • Dedicated contention access TI for resource requests • Resource announcement • How does ECCF handle mixed traffic? • Fast resource request/grant scheme permits to adapt in real time to application needs variations • Resource request can be sent to the RRM through in-band signalling in any TI allocated to the transmitter (whatever its destination), • Otherwise it can be sent in a signalling-dedicated contention access TI. • TI allocation broadcast at the beginning of each TDM frame Bonneville,Patillon Mitsubishi/Motorola

  40. Stack overview • MAC layer is enhanced with the “Extended Centralised Coordination Function” mode (ECCF). • Functions are distributed over 4 sub-layers 802.2 LLC 802.2 LLC ECCF MAC Legacy 802.11 MAC Packet Sequence Number Assignments MAC Header Compression LLCCS Sequence Number Assignments Fragmentation Encryption MDU Header + CRC SAR Segment Sequence Number Assignments Segmentation/Re-Assembly Error and Flow Control MIS Encryption MPDU Header Signalling Insertion MLS PHY PHY Bonneville,Patillon Mitsubishi/Motorola

  41. Frame structure and timing • 802.11 MAC Super Frame & Beacon kept for compatibility. • A part of the Contention Free Period (CFP) divided into MAC Time Frame (MTF) of fixed duration (for example 2 ms). • Resource scheduling performed on a per MTF basis. Time Intervals (TI) of variable duration dynamically allocated to STAs within an MTF. 802.11 MAC Super Frame CFP CP CFP MTF Period for ECCF Period for PCF/HCCA access Period for DCF/EDCA access Period for ECCF Beacon Beacon Beacon Information CF Parameter Set ECCF Parameter Set Bonneville,Patillon Mitsubishi/Motorola

  42. Frame structure and timing (cont.) • ECCF insertion into CAP: CAP generated by the HC using CF-Poll data frame as defined in the 802.11e extension. • CF-Poll contains the RRM MAC address (HC and RRM can be distinct) as destination address, and allocates a reserved time period for ECCF. • CAP is split by the RRM into successive MTFs of fixed duration, each being described by a PGPM broadcast at the beginning of the MTF. SIFS PIFS MTF DIFS CF-Poll PGPM PGPM Data Data CAP Legacy MAC frame ECCF MAC frame Bonneville,Patillon Mitsubishi/Motorola

  43. Frame structure and timing (cont.) • TI constituted of one MPDU = data unit exchanged with the PHY layer as in legacy 802.11 (i.e. one PLCP preamble per MPDU) • MPDU contains two parts: signalling and data • contents defined by the emitter (source STA) • data and signalling can be intended for one or more destination STAs • Possible long PHY bursts • MTF composition defined in a specific MPDU = PGPM MTF MPDU MPDU MPDU MPDU PGPM Data Data Data Data PGPM TI#0 TI#1 TI#2 TI#3 TI#4 Bonneville,Patillon Mitsubishi/Motorola

  44. Power Saving • Inherent power saving facilities • An active STA doesn’t need to listen to all MPDUs • Only resource grants announcements and traffic it is destined to • STA may be on a low power scheme otherwise • Long-term power saving: • RRM allows an STA to enter sleep mode when it has no more traffic to schedule for it • RRM will grant resource to that STA after the sleeping period • During sleep mode, traffic is buffered in any source STA as there is no resource granted for it • Compatible with direct link communication Bonneville,Patillon Mitsubishi/Motorola

  45. System Performance Bonneville,Patillon Mitsubishi/Motorola

  46. Simulations • Unique MAC configuration (no knob activation nor parameter tuning depending on the context or scenario) • Simulation conditions: • MAC, EC and segmentation overhead fully taken into account • Dynamic resource allocation based on requests from STA • Simple Round Robin scheduler (per priority level), 2 priority classes • No contention period, 2 ms long MTF • PHY modes • Signaling in robust PHY modes • Data in MIMO (2x2 up to 3x3), 20 MHz (from 6 Mbit/s up to 216 Mbit/s) • PHY abstraction in system simulation (preliminary configuration) • PHY mode selected with respect to the average SNR at the receiver • PER uniformly distributed in time Bonneville,Patillon Mitsubishi/Motorola

  47. ECCF Robustness • MAC Efficiency vs PER (Scenario I bis, IV, VI bis) • Slight impact of the PER on MAC efficiency • retransmission with low signalling SR-ARQ • MAC efficiency: • Robust vs PER • > 60% even for harsh conditions (*) • High performance even in bad radio conditions Results valid whatever the application packet size (c.f.segmentation) (*) PER for 134 bytes packets, 1E-1 equivalent to 9.5E-1 for 4000 bytes or 6.9E-1 for 1500 bytes packets Bonneville,Patillon Mitsubishi/Motorola

  48. ECCF Scalability • Goodput at MAC SAP vs PHY data rate (point-to-point scenario) • linear variation • MAC efficiency: • Constant vs PHY rate • High level: [76% ; 86%] • Fully scalable for high bit rates Results valid whatever the application packet size (c.f.segmentation) Bonneville,Patillon Mitsubishi/Motorola

  49. Mixed traffic handling • Capacity usage at MAC-SAP vs. Number of VoIP sessions • 1 TCP data flow transmitted using MIMO 3x3_64QAM2/3 (Ns=3) [144Mbit/s] • VoIP: 120-byte packets emitted every 10 ms (2x96kbit/s) • n VoIP sessions, using either 2x2_64QAM2/3 (Ns=1) [48Mbit/s] or 2x2_16QAM1/2 (Ns=1) [24 Mbit/s] • MAC Efficiency between 78% and 55% • 30 VoIP sessions + at least 65 Mbit/s of TCP traffic Bonneville,Patillon Mitsubishi/Motorola

  50. Delay performances • IEEE TGn Usage models : Scenario I (Home) • Traffic classification based on priority level (VoIP > TCP) • Delay comparison for different error rate [cdf(d>D)] • Strong QoS constraints of VoIP reached: • with a simple centralised scheduling • an efficient ARQ • Max delay below 20 ms for QoS traffic Bonneville,Patillon Mitsubishi/Motorola

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