1. <January 2002>
doc.: IEEE <02/139r0>
March, 2008
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Performance Issue in terms of ACK policies with/without Aggregation ]
Date Submitted: [March 16, 2008]
Source: [Wooyong Lee1, Jinkyeong Kim1, Yongsun Kim1, Kyeongpyo Kim1, Hyoungjin Kwon1,
Seung-Eun Hong1, Kyungsup Kwak2, Seokho Kim2, Xizhi An2, Saurabh N. Mehta2, Sangkyoon Nam2, Bumjung Kim2 ]
Company: [Electronics and Telecommunications Research Institute (ETRI)1,Inha University2]
Address: [ETRI, 161 Gajeong-dong, Yuseong-gu, Daejeon, , Republic of Korea]1,[ 6-141B, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon, , Republic of Korea]2
Voice: [], FAX: [], (other contributors are listed in “Contributors” slides)]
Re: []
Abstract: [We analyze the performance of “3c” MAC when the frame error is introduced. The effects of ACK policies w/wo aggregation are considered. ]
Purpose: [To be considered in IEEE c standard]
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 contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P
ETRI
Chuck Brabenac, Intel Labs

2. Contributors Name E-mail Affiliation Wooyong Lee wylee@etri.re.kr ETRI
March, 2008
Contributors
Name
Affiliation
Wooyong Lee
ETRI
Jinkyeong Kim
Yongsun Kim
Kyeongpyo Kim
Hyoungjin Kwon
Seung-Eun Hong
Kyungsup Kwak
Inha University
Seokho Kim
Xizhi An
Saurabh N. Mehta
Sangkyoon Nam
Bumjung Kim
ETRI

3. Case Study 1080p video stream 16 ms superframe size
March, 2008
Case Study
1080p video stream
16 ms superframe size
Superframe Sizing Procedure for Uncompressed Video Traffic [doc.: IEEE c]
ETRI

4. Uncompressed Video Streaming
March, 2008
Simulation Model (UM1)
PNC
Control/commands
Beacon
Uncompressed Video Streaming
DEV-0
DEV 1
2000Mbps
Common mode (48.5 Mbps)
Uncompressed Traffic Model :1080p 30f 20b
- 2200( )*1125( )*30*20 = Gbps
- CBR traffic -> 44000bit (2200*20) / 29.63us
ETRI

5. 802.15.3c Performance Metrics Throughput End-to-End Delay
March, 2008
c Performance Metrics
Throughput
measured in terms of bits per second, is the amount of data delivered successfully by the peer MAC-SAP.
End-to-End Delay
measured in terms of second, is the amount of time taken for a MAC SDU to be transferred from the MAC-SAP of the transmitter to the peer MAC-SAP of the receiver.
Memory usage (MAC)
Memory usage represent the minimum buffer size required for continuous video representation
ETRI

6. Considering Superframe Structure
March, 2008
Considering Superframe Structure
ETRI

7. Preamble and PLCP Header
March, 2008
Parameters Assumed
Use common mode beacon to 47.8 Mbps
Random packet error
Set video traffic to CBR traffic mode
One MAC SDU is composed of data bits transmitted in one horizontal line.
Assume no buffer delay due to higher data rate
Assume no propagation delay due to short distance ( < 10 meter)
Consider transmission delay in terms of Overhead & Payload Size
Simulate in the NS-2
Parameters
Value
Superframe Size
16 ms
Beacon Interval us
CAP Duration
0 us
Guard Time
0.02 us
SIFS
2.5 us
Preamble and PLCP Header
8.157 usec
PHY-SAP Rate
2000 Mbps
Payload Size
5.5 KB
Sub-header Size
4 Bytes
ACK Policy
No ACK, Imm-ACK,Dly-ACK
Aggregation Method
Applied
MAC-SDU Size
ETRI

8. MAC Throughput without Aggregation
March, 2008
MAC Throughput without Aggregation
Superframe size = 16 ms, Preferred payload size = 5.5k
ETRI

9. MAC Throughput with Aggregation
March, 2008
MAC Throughput with Aggregation
ETRI

10. March, 2008
ETRI

11. March, 2008
Conclusions
We present the performance comparison in terms of ACK polices with or without aggregation.
Numerical and simulation results show that the aggregation scheme can improve the throughput results to a large extend.
Different ACK policies result in different throughputs.
No ACK has the highest efficiency, but it can not provide reliable data transfer.
Imm-ACK has the lowest performance.
Dly-ACK can improve throughput.
Number of pending frames should not be small
On the other hand, delay jitter may be larger.
ETRI

12. Suggestions for setting ACK policies
March, 2008
Suggestions for setting ACK policies
RT traffic (video streaming)
Constant bandwidth and stringent timing requirement
No ACK policy is preferred
Imm-ACK and Dly-ACK have poor throughput performance.
Retransmission is useless and broken frames are directly discarded.
If a frame error occurs, retransmission doubles the delay.
If n-Dly-ACK is applied, the delay due to retransmission is correspondingly increased n times.
High power consumption to insure that frame can be successfully transmitted and received.
NRT traffic (data transfer)
ACK and retransmission is needed to correct frame errors
n-Dly-ACK is preferred.
Very high reliability (packet delivery ratio is almost 100%), if delay jitter requirement is not strict.
Extend the coverage range or reduce the need for transmit power.
Bi-directional communication
Imp-ACK is preferred.
ETRI

13. March, 2008
Appendix
ETRI

14. Parameters on Video Resolution
March, 2008
Parameters on Video Resolution
Formant
V Freq
HRES
VRES
DE_CNT
DE_LIN
Rate 24bit
Rate 20bit
Hsync (sec)
Vsync (sec)
1080i 30
2200
562/ 563
1920
1080
5760
4800
E-06 /
1080p
1125 60
E-06
ETRI