1. <author>, <company>
doc.: IEEE <doc#>
<month year>
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Adding BA base sequence number]
Date Submitted: [March 18, 2007]
Source: [Zhou Lan, Chang-woo Pyo, Fumihide Kojima, Hiroyuki Nakase, Shuzo Kato, Gal Basson(2) , Tal Azogui(2)]
Company [National Institutep of Information and Communications Technology (NICT), Wilocity(2)]
Address1[3-4 Hikari-no-oka, Yokosuka-shi, Kanagawa , Japan]
Voice1:[] , FAX1: []
other contributors are listed in “Contributors” slides]
Re: [In response to TG3c comments (IEEE P c)]
Abstract: [Comment resolutions]
Purpose: [To be considered in TG3C baseline document.]
Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributors acknowledge and accept that this contribution becomes the property of IEEE and may be made publicly available by P
<author>, <company>
Page 1

2. Comment # 63 63 GB
DF3
65-66 T
PHY
add a "Block-ACK base sequence field" (to optional MAC header adjuscent to BA field) - in order resolve ACK/NAK correlation ambiguity of corrupted MSDU number and BA-bit-offset

3. Block ACK / aggregated MSDU correlation problem description
current Draft text suggests that correlation of MSDU sequence to Block ACK bit offset, is based on its order-offset in the frame.
MSDU sequence numbers in the MAC frame body are not necessarily consecutive
(e.g. in case of selective retransmit)
there is no way to tell how many MSDU’s are corrupted (assuming MSDU headers are also corrupted)
No way to set/clear the correlated bit in the block-ACK

4. Problem description diagram
DEV1
DEV2
PHY HDR
MAC HDR BA
MSDU
#11
#12
#13
#14
PHY HDR
MAC HDR BA
{0,1,0,1,…}
MSDU
# …
PHY HDR
MAC HDR BA
MSDU
#11
#13
#15
#16
#17
PHY HDR
MAC HDR BA
{???,1,1,1,…}
MSDU
# …
Unknown number of MSDU corrupted from the beginning of the frame

5. Block ACK / aggregated MSDU correlation suggested solution
Add “Block ACK– base sequence number” to the transmitted “MAC optional header”.
Each bit offset in the block ACK, is taken as the offset from the BA-base sequence (in the MAC optional header) to the MSDU sequence number

6. Solution description diagram
DEV1
DEV2
PHY HDR
MAC HDR BA
MSDU
#11
#12
#13
#14
PHY HDR
MAC HDR
BA-BASE
# 12 BA
{1,0,1,…}
MSDU
# …
PHY HDR
MAC HDR BA
MSDU
#11
#13
#15
#16
#17
PHY HDR
MAC HDR
BA-BASE
# 15 BA
{1,1,1,…}
MSDU
# …
Corrupted leading MSDU # are NOT acknowledged –
receiver of the BA required to retransmit non-ACKed MSDU (lower than BA-BASE )

7. Frame Structure Add BA Base Sequence number – 12 bits field
First 3 nibbles- are the base sequence number for the current aggregated MSDU
Last nibble - reserved