1. June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [15.3c MAC attributes for enhanced uses]
Date Submitted: [16 Jan, 2007]
Source: [Noriyasu Kikuchi, Tadahiko Maeda, Hideto Ikeda, Kiyohito Tokuda] Company [Oki Electric Industry Co., Ltd.]
Address [3-4 Hikari-no-oka, Yokosuka-shi, Kanagawa, , Japan]
Voice:[ ],
Re: [Request of contributions for Usage Models for UMD subgroup]
Abstract: [Proposal of MAC attributes]
Purpose: [To be adapted in 15.3c MAC recommendation]
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
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

2. Contents Background System Outline System Requirements
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Contents
Background
System Outline
System Requirements
MAC Requirements
High Efficient Media Access
Bandwidth Control
Conclusion
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

3. Wireless Home Video Network (WIS@H:Wireless Integrated Server at Home)
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Background
As one of Usage Models, Oki proposed in ‘Wireless Home Video Network（06/286r3）’ at San Diego meeting in Sep, 2006.
It consists of multiple usage models, which may be any of UM1-UM5.
For efficient operation of such a combined system, additional MAC attributes are essential.
This contribution proposes such enhanced MAC attributes.
15.3c MAC
Basic Part
Enhanced Part
UM1-UM5
Wireless Home Video Network Integrated Server at Home)
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

4. June, 2006
doc.: IEEE /xxxr0
Jan, 2007
System Outline
Basic concept: A server based high-speed video contents distribution system in home.
・A whole system consists of a home video server, AV equipment (like HDTV), PCs, and repeaters deployed in home, which are linked with mmWave radio.
・A home video server, as a home gateway, controls compressed video contents from TV broadcast and NGN as well as those stored in a home library.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

5. System Requirements System Requirement Technical Issue
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
System Requirements
System Requirement
Technical Issue
Simultaneous use of multiple applications, like video streaming and file transfer, from many devices
Requires very high throughput
Estimation of desired throughput, assuming four family members in home Applications：compressed video streaming = 25Mbps file down/upload = Mbps (limited by HDD performance) Total: 25x x4 = 1,300 Mbps
Equivalent quality of service in any room
Repeater function makes quality control more difficult and complex.
Available in any room in home
mmWave cannot penetrate walls between rooms. The range may be less than 5 meter in free space for higher data rate.
The smaller number of repeaters to cover all devices by one to N operation
One to N (one repeater and N devices) operation may cause a hidden terminal problem.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

6. MAC Requirements MAC attributes for satisfying system requirements
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
MAC Requirements
MAC attributes for satisfying system requirements
System Requirement
Simultaneous use of multiple applications, like video streaming and file transfer, from many devices
Equivalent quality of service in any room
Availability in any room in home
The smaller number of repeaters to cover all devices by one to N operation
MAC attribute
Description
High efficiency media access
Allocating short unique backoff length to device in advance.
Throughput Distribution (QoS control)
Using proportional backoff allocation corresponding to the ratio of necessary throughput of devices.
Bridging
Bridging multiple piconets on different channels
Network management
Operating multiple piconets as one network (Cluster network)
Solution of a hidden terminal problem
Avoiding collisions in a situation that carrier sense is not available （ex. RTS/CTS）
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

7. Proposed MAC attributes
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Proposed MAC attributes
We propose that the following attributes should be included in 15.3c MAC Recommendation.
High efficiency media access
Throughput distribution (QoS control)
Bridging (Repeating function at MAC sublayer)
Network management (Cluster network)
Solution of a hidden terminal problem
We have evaluated the first two attributes and show the results.
The last three attributes are now being evaluated.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

8. High Efficiency Media Access
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
High Efficiency Media Access
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

9. Conventional CSMA/CA: Mechanism & Problem
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Conventional CSMA/CA: Mechanism & Problem
●Mechanism
Determine a random backoff length
previous communication
DEV1
ACK
start transmission
backoff length＝2
DATA
DEV2
backoff length＝3
DATA
DEV3
give up transmission
Backoff time = Backoff length * Slot time
●Problem
Backoff length may become longer than expected because of random backoff algorithm.
When backoff length coincides with those of other devices, a collision occurs.
Backoff time is too long
ACK
DEV1
DEV1
DATA
DATA
DEV2
DEV2
Collision
DATA
DEV3
DEV3
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

10. Short Unique Backoff Allocation - Algorithm
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Short Unique Backoff Allocation - Algorithm
This system knows the number of devices in advance. It is not necessary to determine a random backoff length. ⇒ Allocate a short unique backoff length to individual devices in advance.
<Procedure for the event that total number of devices changes> Step1) PNC increases the number of devices when a new device is joining. Decreases it when a associated device is leaving or disappear.
Step2) PNC determines a pattern of backoff of devices such that every device has a unique backoff length anytime and a value is less than the number of devices.
Step3) PNC informs every devices in the Piconet of the pattern.
<Procedure of a data transmission> Step1) A device senses a carrier for BIFS to confirm that other device is not transmitting.
Step2) The device determines a backoff length by using the given pattern. (In case of conventional CSMA/CA, a length is determined independently and at random)
Step3) The device transmits a DATA frame when backoff time expires. If other device starts to transmit a DATA frame earlier, the device gives up the transmission.
Step4) The corresponding device returns an ACK frame for the DATA frame.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

11. Short Unique Backoff Allocation
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Short Unique Backoff Allocation
Backoff length pattern ２
Shortest necessary length for # of DEVs 1
DEV1 １ ０ 2
No duplication A collision never happens because each device has unique backoff length anytime.
backoff length ２ 1
DEV2 １ ０ ２
DEV3 2 １ ０
Media access time chart
When amount of traffic exceeds a threshold , total throughput goes the highest because the minimum backoff length is always 0.
ACK
ACK
DEV1
BIFS
backoff＝1
backoff＝2
DATA
DEV2
backoff＝0
DATA
Backoff length is short (less than 3).
DEV3
backoff＝2
BIFS:Backoff IFS
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

12. Initial setting condition
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Simulation and Result
●System configuration
Initial setting condition
Value
PHY data rate
1 Gbps
SIFS (Short IFS)
0.9 usec
BIFS (Backoff IFS)
1.5 usec
Slot time
CW (Contention Window) # In the case of random backoff 16
DATA frame size
1540byte
Control frame size
64byte
BER
error free
Traffic of each device
unlimited
Server
・・・
DEV1
DEV2
DEV3
DEV8
●Result
Total throughput stays constant around 680Mbps independent of the number of devices.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

13. Throughput distribution （QoS Control）
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Throughput distribution （QoS Control）
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

14. June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Problem on QoS Control
Purpose
To allocate necessary throughput to individual devices.
Problem
15.3 and 15.3b MAC do not have function of the throughput control in CAP.
Throughput allocation is not feasible even by using the QoS control with priority classes (802.11e).
CAP: Contention Access Period
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

15. Weighted Short Unique Backoff Allocation
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Weighted Short Unique Backoff Allocation
Allocate proportional short unique backoff corresponding to the ratio of necessary throughput of individual devices.
●Case
Throughput should be controlled in the following ratio 　　 DEV1: DEV2 : DEV3 = 1 : 2 : 1.
●Method
Frequency that backoff length is 0 of DEV2 doubles that of other devices. ２
DEV1
・・・・ １ ０
backoff length
Double ２
DEV2 １
・・・・ ０ ２
DEV3 １
・・・・ ０
Chance of DEV2 transmission becomes as double as that of other devices.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

16. Initial setting condition
June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Simulation and Result
●System configuration
R1- R4 :Repeater
Initial setting condition
Value
PHY data rate
1 Gbps
SIFS (Short IFS)
0.9 usec
BIFS (Backoff IFS)
1.5 usec
Slot time
CW (Contention Window) # In the case of random backoff 16
DATA frame size
1540byte
Control frame size
64byte
BER
error free
Traffic of each device
100Mbps
CH1 (hop 1)
CH2 (hop 2)
CH3 (hop 3)
CH1 (hop 4)
CH2 (hop 5) R1 R2 R3 R4
server 8 6 4 2 1 1 1 1 1 1 1 1 1 1
DEV ID １ ２ ３ ４ ５ ６ ７ ８ ９ １０
In the case of weighted Short Unique Backoff (6 is the number of devices in downstream)
●Result
By Weighted Short Unique Backoff algorithm, equal throughput was achieved among all devices independent of hop count.
A conventional backoff algorithm did not perform QoS control. Throughput of a device through more hops became lower.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.

17. June, 2006
doc.: IEEE /xxxr0
Jan, 2007
Conclusion
We extracted five MAC attributes necessary for application.
High efficiency media access
Throughput distribution (QoS control)
Bridging (Repeating function at MAC sublayer)
Network management (Cluster network)
Solution of a hidden terminal problem
We proposed them as additional MAC attributes of 15.3c MAC recommendation.
We finished evaluation by simulation to validate solutions of two of them. We continue working for remaining three.
Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.
Tadahiko Maeda, Oki Electric Industry Co., Ltd.