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1、Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 1,Project: IEEE P802.15 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 T
2、okuda Company Oki Electric Industry Co., Ltd. Address 3-4 Hikari-no-oka, Yokosuka-shi, Kanagawa, 239-0847, Japan Voice:+81-46-847-5141, E-Mail:, , , Re: Request of contributions for Usage Models for UMD subgroup Abstract: Proposal of MAC attributes Purpose: To be adapted in 15.3c MAC recommendation
3、 Notice: This document has been prepared to assist the IEEE P802.15. 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
4、(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 P802.15.,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 2,Contents,Backgro
5、und System Outline System Requirements MAC Requirements High Efficient Media Access Bandwidth Control Conclusion,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 3,Background,As one of Usage Models, Oki proposed WISH in Wireless Home Video Network（06/286r3） at San Diego meeting in S
6、ep, 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.,Enhanced Part,UM1-UM5,Wireless Home Video Network (WISH:Wireless Integrate
7、d Server at Home),15.3c MAC,Basic Part,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 4,System Outline,Basic concept: A server based high-speed video contents distribution system in home.,A home video server, as a home gateway, controls compressed video contents from TV broadcast
8、and NGN as well as those stored in a home library.,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.,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 5,System Requirements,Jan, 2007,Nori
9、yasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 6,MAC Requirements,MAC attributes for satisfying system requirements,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 7,Proposed MAC attributes,We propose that the following attributes should be included in 15.3c MAC Recommendation
10、. 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 evalu
11、ated.,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 8,High Efficiency Media Access,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 9,Conventional CSMA/CA: Mechanism & Problem,backoff length2,backoff length3,DEV1,DEV2,DEV3,DATA,ACK,DATA,previous communication,giv
12、e up transmission,Determine a random backoff length,Mechanism,start transmission,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.,DEV1,DEV2,DEV3,Backoff time is too long,DEV1,DEV
13、2,DEV3,Collision,DATA,ACK,DATA,DATA,Backoff time = Backoff length * Slot time,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 10,Short Unique Backoff Allocation - Algorithm, Step1) A device senses a carrier for BIFS to confirm that other device is not transmitting. Step2) The devic
14、e 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 transmi
15、ssion. Step4) The corresponding device returns an ACK frame for the DATA frame., 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
16、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.,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 indivi
17、dual devices in advance.,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 11,Short Unique Backoff Allocation,DEV3,DEV2,DEV1,backoff length,backoff1,backoff2,DEV1,DEV2,DEV3,DATA,ACK,DATA,ACK,backoff2,backoff0,0,Shortest necessary length for # of DEVs,When amount of traffic exceeds a
18、threshold , total throughput goes the highest because the minimum backoff length is always 0.,2,1,1,2,Backoff length pattern,Media access time chart,Backoff length is short (less than 3).,No duplication A collision never happens because each device has unique backoff length anytime.,BIFS,BIFS:Backof
19、f IFS,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 12,Simulation and Result,Total throughput stays constant around 680Mbps independent of the number of devices.,System configuration,DEV1,DEV2,DEV3,DEV8,Server,Result,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Sli
20、de 13,Throughput distribution （QoS Control）,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 14,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 allocat
21、ion is not feasible even by using the QoS control with priority classes (802.11e).,CAP: Contention Access Period,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 15,Weighted Short Unique Backoff Allocation,Allocate proportional short unique backoff corresponding to the ratio of nece
22、ssary throughput of individual devices.,Case,DEV3,DEV2,DEV1,backoff length,Chance of DEV2 transmission becomes as double as that of other devices.,Method,Frequency that backoff length is 0 of DEV2 doubles that of other devices.,Double,Throughput should be controlled in the following ratio DEV1: DEV2
23、 : DEV3 = 1 : 2 : 1.,Jan, 2007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 16,Simulation and 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. Throughp
24、ut of a device through more hops became lower.,CH1 (hop 1),server,1,1,6,DEV ID,CH2 (hop 2),CH3 (hop 3),CH1 (hop 4),CH2 (hop 5),R1,System configuration,Result,R1- R4 :Repeater,R2,R3,R4,In the case of weighted Short Unique Backoff (6 is the number of devices in downstream),1,1,8,1,1,4,1,1,2,1,1,Jan, 2
25、007,Noriyasu Kikuchi, Oki Electric Industry Co., Ltd.,Slide 17,Conclusion,We extracted five MAC attributes necessary for WISH 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.,