1. Ack Bitmap length for Burst ACK
July 2001
doc.: IEEE /434r1
January 2002
Ack Bitmap length for Burst ACK
Yasuo HARADA,
Isaac Lim Wei Lih
(Matsushita Electric Ind.)
Yoshihiro OHTANI,
Srinivas KANDALA
( Sharp Corp. )
Matsushita / Sharp
Wei Lih Lim, Matsushita Electric Ind.

2. HD TV Transmission Requirement
July 2001
doc.: IEEE /434r1
January 2002
HD TV Transmission Requirement
Streaming rate: 24Mbps
36Mbps OFDM – a with 16QAM
Burst ACK to achieve higher throughput
MPDU size = 1402 bytes
MPDU Pay load Size = MSDU SIZE
Bitmap ACK need to contain enough acknowledgement history to achieve the high throughput of 24Mbps
Burst ACK is a factor feature to support HD TV transmission using a 16QAM modulation
In order to avoid excessive delay due to lost of burst ack, bitmap need to carry a certain amount of acknowledgement history
Matsushita / Sharp
Wei Lih Lim, Matsushita Electric Ind.

3. 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
Matsushita / Sharp

4. Simulation for Burst ACK
July 2001
doc.: IEEE /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: 36Mbps
MSDU Size: 1402 Bytes
Direct Transmission from source to destination (no relaying)
Data
Burst ACK
Burst ACK Req
QoS CF-Poll
Throughput is mac layer throughput
Delay is end-to-end the layer which generate and receive MPDU data payload.
Matsushita / Sharp
Wei Lih Lim, Matsushita Electric Ind.

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

6. 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
Matsushita / Sharp

7. Suggestion for changing to D2.0
January 2002
Suggestion for changing to D2.0
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 16 bytes bitmap ack for unfragmented MPDU
Matsushita / Sharp

8. Recommend text change for section 7.2.1.8
January 2002
Recommend text change for section
The frame format of the Burst Acknowledgement (BurstAck) frame is defined as follow:
BurstAck Frame Format
Use a reserve bit in Burst Control field to indicate if fragments are included in Ack Bitmap for acknowledgement.
Matsushita / Sharp

9. Section 7.2.1.8 Burst Acknowledgement
January 2002
Section Burst Acknowledgement
The following are recommended insertion to the text in section :
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).
Matsushita / Sharp