IEEE P802.15 Working Group for Wireless Personal Area .ppt

1、March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 1,IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Submission Title: Summary of Mobilian+Symbol Joint Proposal Date Submitted: March 13, 2001 Source: Steve Shellhammer & Jim Lansford Compa

2、ny: Symbol Technology, Inc. & Mobilian Corp. Address1: One Symbol Plaza, Holtsville NY 11742 Address2: 7431 NW Evergreen Parkway, Suite 220, Hillsboro, OR 97124 Voice1: (631) 738-4302, FAX: (631) 738-4618, E-Mail: Voice2: (405) 377-6170, Fax: (425) 671-6099, E-Mail: Jim.L Re: Submission of a Coexis

3、tence Mechanism in response to IEEE 802.15-00/009r4 Abstract: This is a closing summary of the Mobilian+Symbol Proposal for Collaborative Coexistence Purpose: This summary highlights the key issues in the joint proposal. Notice: This document has been prepared to assist the IEEE P802.15. It is offer

4、ed 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

5、contributors acknowledge and accept that this contribution becomes the property of IEEE and may be made publicly available by P802.15.,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 2,IEEE P802.15 Working Group for Wireless Personal Area NetworksTM,Collabo

6、rative Coexistence Mechanism Submission: Mobilians META + Symbols TDMA Summary for Voting,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 3,Examination of the issues,Addressing open issues Fairness of the approaches Switching between modes Actual implementa

7、tion performance Summary,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 4,What about fairness?,Mobilian proposal BT SCO always gets right of way Data traffic takes turns (just like a 4-way stop) but META can be instructed to prefer one over the other (prio

8、rity road) Symbol proposal Acts exactly like a traffic lightTDMA,TI Proposal BT SCO always gets the right of way If two packets come to intersection, light flips a “weighted” coin to decide which goes first-increases latency,WLAN Traffic,BT Traffic,The traffic models can be compared to an intersecti

9、on.,BUT-META is an overpass! Allows simul-taneous BT-WLAN Rx or TxMUCH higher throughput,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 5,What about mode transitions in the merged proposal?,If no Symbol AP present, META devices manage their local bubble If

10、 Symbol AP present, META devices will always follow its lead Symbol APs only go into TDMA mode in high concentration areas, under command of AP management SW This is application specific, and is either/or If Symbol AP doesnt tell STA to do TDMA, it does META This is the normal mode,March 2001,Steve

11、Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 6,The Mobilian Approach is real,Mobilians coexistence technology has been demonstrated in a hardware implementation,Source: Mobilian TrueRadio Demo COMDEX 2000Demo Set-up: * Notebook PC with collocated BT & 802.11b * BT node 1

12、 m away * 802.11b AP 15 m away in walled office environment,802.11b; BT=OFF,802.11b with TrueRadio; BT=ON,802.11b; BT=ON,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 7,Conclusion,The Mobilian+Symbol approach is well researched, simulated, and documented

13、It solves the coexistence problem using TDMA, and works for any number of piconetsThank you for your support,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 8,Backup,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide

14、9,Simulation Program Update,Bluetooth Nodes: +20dBm AP: 802.11b (+20dBm) STA: META (+20dBm),March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 10,Conference Room Usage,Many stations, each with independent piconets Bluetooth speakerphone As before, aggregate th

15、roughput is shared among all users,Back to Single User Scenario,Conference Room Scenario,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 11,Office Usage Model,Cluster of users in cubicles, each of which has an independent piconet Throughput is aggregate thr

16、oughput measured from Access Point,Back to Single User Scenario,Office Scenario,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 12,Individual User,BT headset operating from same laptop as Wi-Fi station,Individual Scenario,March 2001,Steve Shellhammer, Symbo

17、l Technologies Jim Lansford, Mobilian Corporation,Slide 13,WLAN Throughput in an Office Scenario,Cluster of users in cubicles, each of which has an independent piconet Throughput is aggregate throughput measured from Access Point,0,1,2,3,4,5,6,7,8,1,10,100,Distance from AP (m),WLAN Throughput (Mb/s)

18、,no interference,non TR,Office Scenario,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 14,Symbols TDMA,Time,802.11 beacon interval,BT-WLAN boundary (possibly delimited by CTS),Traffic scheduling by fixed intervals or by offered loadCTS command can force WL

19、AN nodes non-hidden nodes to cease operationCan manage unlimited number of piconets,BT,WLAN,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 15,Mobilians META,Dynamic algorithm schedules traffic Knowledge of time-frequency collisions is key Simultaneous tran

20、smission or reception allowed Tx simultaneous with Rx allowed if not in-band (requires good LNA) Critical for SCO operation-WLAN can work around in-band collisions This figure does not show polls/nulls, which often dominates Bluetooth traffic,Time,802.11 beacon interval,(Packet widths are not to sca

21、le),BT,WLAN,March 2001,Steve Shellhammer, Symbol Technologies Jim Lansford, Mobilian Corporation,Slide 16,Benefits of Approaches,Both will operate in the same device, through a common antenna Both techniques can be built into same device TDMA is good for high piconet density META is for BT SCO, and gives better throughput, especially when few piconets are nearby For reference, see 00360r0P802-15_TG2-Mobilian_coexistence_proposal 01025r0P802-15_TG2-TDMA-80211-Bluetooth,