1. IEEE 802.15.2 DRAFT RECOMMENDED PRACTICE Clause 14: Collaborative Coexistence Mechanism – IEEE 802.11 and 802.15.1 Steve Shellhammer (Symbol Technologies) Jim Lansford, Adrian P Stephens (Mobilian Corporation)

2. Outline Introduction (5) Collaborative Mechanism (14) (MAC Layer Solution) Simulation Result (4) Conclusion Reference

3. Introduction (1/5) 4 Task Groups TG1: WPAN/Bluetooth TG2: Coexistence TG3: WPAN High Rate TG4: WPAN Low Rate 1 Public Committee

4. Introduction (2/5) 802.15.2 Scope To develop a recommended practice for an IEEE 802.15 Wireless Personal Area network that coexists with other selected wireless devices operating in unlicensed frequency bands

5. Introduction (3/5) Two Categories: Collaborative Mechanism (Collocated) To be defined as a coexistence mechanism where WPAN and WLAN exchange information between one another to minimize mutual interference Non-Collaborative Mechanism No exchange of information is used between two wireless

6. Introduction (4/5)

7. Introduction (5/5) Non-collaborative mechanism summary: AFH (Adaptive Frequency Hopping) Adaptive Packet Selection and Scheduling Transmit Power Control / Rate Scaling Collaborative mechanism summary : Per-Transmission Request/Confirm TDMA-Base Mechanism

8. Collaborative Mechanism Introduction Collaborative Mechanism (14) (MAC Layer Solution) Simulation Result Conclusion Reference

9. Collaborative Mechanism (1/14) By sharing information between collocated 802.11 and 802.15.1 stacks and locally controlling transmissions to avoid interference No new on-air signaling is required Be interoperable with devices that do not include it

10. Collaborative Mechanism (2/14) Overall Structure: AWMA Control

11. Collaborative Mechanism (3/14) AWMA Control Entity 802.11 AP and 802.15 master are collocated MEHTA Control Entity 802.11 STAs and 802.15 slaves are collocated

12. Collaborative Mechanism (4/14) Alternating Wireless Medium Access Feature: 802.15 master and 802.11 AP should collocated in the same physical unit 802.11 STAs are synchronized by AP 802.11 AP should send a physical synchronization signal to 802.15 master WPAN slavers s ACL data transmission is controlled by 802.15 master Limitation: Could not support SCO link

13. Collaborative Mechanism (5/14) AWMA TBTT

14. Collaborative Mechanism (6/14) Structure of the MEHTA Entity

15. Collaborative Mechanism (7/14) Known Physical-Layer Characteristic 802.11b pass-band 802.15 hopping pattern Local 802.11 Activity Local 802.15.1 Activity TransmitReceive In-bandOut-of-bandIn-bandOut-of-band Transmit NoneTransmit-Receive or None ReceiveTransmit-Receive or None ReceiveNone

16. Collaborative Mechanism (8/14) Known 802.11 States: Current or expected receive and transmit activity Channel number Current State End Time 802.11 Tx Request State: Packet Type Duration

17. Collaborative Mechanism (9/14) Known 802.15 States: Current or expected receive and transmit activity Channel List Duration Time Remaining

18. Decision Logic for 802.11 Tx Request

19. Collaborative Mechanism (11/14) Access Mechanism Effect of Tx Confirm (status=denied) DCFThe denied result appears to be a transient carrier-sense condition that requires a DIFS time to expire before a subsequent transmit request can be made. The denied result has no effect on the contention window (CW) or retry variables because no transmission has occurred. (But its will aggregate collision…) PCF (as CF-pollable STA) No transmission from the STA occurs, and the AP can resume transmission after a PIFS. (But its will cause wasting…) PCF as PCNo transmission from the AP occurs, and the AP can resume transmission after a PIFS.

20. Decision Logic for 802.15 Tx Request

21. Collaborative Mechanism (13/14) Recommended Priority Comparison An 802.11 ACK MPDU should have a higher priority than all 802.15.1 packets An 802.15.1 SCO packet should have a higher priority than 802.11 DATA MPDUs. Other priority comparisons are a implementation-specific

22. Collaborative Mechanism (14/14) Maintaining QoS A device can optionally monitor QoS by defining metrics (such as PER and delay) Maintaining SCO QoS An implementation can optionally attempt to maintain SCO QoS so as not to exceed some level of SCO packet loss by monitoring the SCO PER and comparing with a threshold. The priority of the SCO packet is increased when the SCO PER is above the threshold.

23. Simulation Result (4) Introduction Collaborative Mechanism (MAC Layer Solution) Simulation Result Conclusion Reference

24. Simulation Tool accurately models experimental WLAN / BT performance Experimental Results (1/4)

25. Conference Room Usage (2/4) Many stations, each with independent piconets Bluetooth speakerphone As before, aggregate throughput is shared among all users Back to Single User Scenario Conference Room Scenario

26. Office Usage Model (3/4) Cluster of users in cubicles, each of which has an independent piconet Throughput is aggregate throughput measured from Access Point Back to Single User Scenario Office Scenario

27. Individual User (4/4) BT headset operating from same laptop as Wi- Fi station Individual Scenario

28. Conclusion Introduction Collaborative Mechanism (MAC Layer Solution) Simulation Result Conclusion Reference

29. Conclusion The Combination of two proposal should revise to be more meaningful There might be some research topic address to the coexistence issue in the 802.11 point of view The QoS mechanism under the coexistence condition might be a discussible issue as well.

30. Reference(1/2) TG2 Submission Matrix IEEE P802.15 Doc 01/078r0 TG2 Coexistence Mechanism Summary Matrix IEEE P802.15 Doc 01/078r2 IEEE 802.15.2 Clause 14.1 - Collaborative Coexistence Mechanism IEEE P802.15 Doc 01/340r0 TG2 Mobilian Draft Text IEEE P802.15 Doc 01/300r1 Clause 14.3 - Adaptive Frequency Hopping IEEE P802.15 Doc 01/366r1

31. Reference(2/2) Clause 1 - Scope and Purpose IEEE P802.15 Doc 01/313r1 Clause 5.1 - Description of the Interference Problem IEEE P802.15 Doc 01/314r0 Clause 5.3 - Overview of Coexistence Mechanisms IEEE P802.15 Doc 01/363r0 Clause 14.2 - MAC Scheduling Mechanism IEEE P802.15 Doc 01/316r0 Collaborative Coexistence Mechanism Submission: META + TDMA IEEE P802.15 Doc 01/164r0