Ack Bitmap length for Burst ACK July 2001 doc.: IEEE 802.11-01/434r1 January 2002 Ack Bitmap length for Burst ACK Yasuo HARADA, Isaac Lim Wei Lih, Tan Pek Yew (Matsushita Electric Ind.) Isaac, Matsushita Electric Ind. Wei Lih Lim, Matsushita Electric Ind.

HD TV Transmission Requirement July 2001 doc.: IEEE 802.11-01/434r1 January 2002 HD TV Transmission Requirement Streaming rate: 24Mbps 36Mbps OFDM – 802.11a with 16QAM Burst ACK to achieve higher throughput MPDU size = 1402 bytes Fragmentation is not needed Bitmap ACK need to contain enough acknowledgement history to avoid excessive delay caused by lost of Burst ACK frame Burst ACK is a factor feature to support HD TV transmission using 802.11a 16QAM modulation Most of the MSDU size for AV steaming is less than 2403 bytes, so fragmentation is not necessary. In order to avoid excessive delay due to lost of burst ack, bitmap need to carry a certain amount of acknowledgement history Isaac, Matsushita Electric Ind. Wei Lih Lim, Matsushita Electric Ind.

Practical example for ACK Bit map requirement January 2002 Practical example for ACK Bit map requirement Q.CF-Poll Data#01 Data#02 Data#03 Data#04 Data#05 Data#06 Data#07 Data#08 ACK Req. Burst ACK Data Long MPDU (No fragmentation) 1 MSDU = 1 MPDU　(ｅｘ．1402　byte) 8 MSDUs per burst Burst ACK ACK-Bitmap : |01|02|03|04|05|06|07|08||09|10|11|12|13|14|15|16| Draft 2.0 Conventional ACK for 16 MSDUs history length Burst ACK ACK-Bitmap : |01|02|03|04|05|06|07|08||09|10|11|12|13|14|15|16| |17|18|19|20|21|22|23|24||25|26|27|28|29|30|31|32| |33|34|35|36|37|38|39|40||41|42|43|44|44|46|47|48| |49|50|51|52|53|54|55|56||57|58|59|60|61|62|63|64| Required for HD TV ACK for 64 MSDUs history length Isaac, Matsushita Electric Ind.

Simulation for Burst ACK July 2001 doc.: IEEE 802.11-01/434r1 January 2002 Simulation for Burst ACK Objective Throughput and Delay v.s. Bitmap Ack Size Scenario for simulation Data Generation Rate: 24,000,000 bps PHY: OFDM @ 36Mbps MSDU Size: 1402 Bytes Direct Transmission from source to destination (no relaying) Dummy scheduler – AP polls sender and receiver in sequence Data Burst ACK Burst ACK Req QoS CF-Poll Throughput is mac layer throughput Delay is end-to-end delay @ the layer which generate and receive MPDU data payload. Isaac, Matsushita Electric Ind. Wei Lih Lim, Matsushita Electric Ind.

January 2002 Throughput Bitmap ack size of 32 or more is needed to solve throughput variation due to lost/error on Burst Ack frame Isaac, Matsushita Electric Ind.

January 2002 End-to-End Delay Bitmap ack size of 32 or more is needed to solve delay jitter due to lost/error on Burst Ack frame Isaac, Matsushita Electric Ind.

January 2002 Conclusion As shown by the simulation results, acknowledging more than 16 MPDUs in a Burst Ack frame is needed to due with erroneous condition Use addition flag to allow full use of the 32 bytes bitmap ack for unfragmented MPDU for cases where data payload is smaller maxMSDU size. Isaac, Matsushita Electric Ind.

Recommend text change for section 7.2.1.8 January 2002 Recommend text change for section 7.2.1.8 The frame format of the Burst Acknowledgement (BurstAck) frame is defined in Figure 21.4. Octets: 2 2 6 32 4 Frame Control Duration RA TA BA Control Sequence Control Ack Bitmap FCS Bits: 0 to 3 4 – 13 15 TID Reserved Wait 14 Fragment Figure 21.4 – BurstAck Frame Format Use a reserve bit in BA Control field to indicate if fragments are included in Ack Bitmap for acknowledgement. Isaac, Matsushita Electric Ind.

Section 7.2.1.8 Burst Acknowledgement January 2002 Section 7.2.1.8 Burst Acknowledgement The following are recommended insertion to the text in section 7.2.1.8: The Duration, RA and TA fields follows the rules defined in section 7.2.1.3 for the ACK frame. The BA control field consists of the TC, Fragment and Wait sub-fields. The TC contains the traffic class being acknowledged. The Fragment field, if set to 1, means that the Ack Bitmap contains fragments acknowledgement and can acknowledge up to 16 MSDUs. Bit position n of Ack Bitmap, if set to a 1 acknowledges MPDU with MPDU sequence number equal to (Sequence Control + n). Otherwise, each bit in the Ack Bitmap represent an acknowledgement for a sequence number, which can acknowledge up to 256 MSDUs. Bit position n, if set to a 1 acknowledges MPDU with MPDU sequence number equal to (Sequence Control + n * 16). The Wait field, if set to 1, means that the acknowledgement results are not available. The contents of the Sequence Control and Ack Bitmap are reserved in this case. Otherwise, the Sequence Control field contains the fragment number and sequence number for traffic class TC corresponding to bit 0 of the Ack Bitmap. Note: Remove existing line 10 – 13. Isaac, Matsushita Electric Ind.