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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). Outline. Introduction (5) Collaborative Mechanism (14)
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IEEE 802.15.2 DRAFT RECOMMENDED PRACTICEClause 14: Collaborative Coexistence Mechanism – IEEE 802.11 and 802.15.1 Steve Shellhammer (Symbol Technologies) Jim Lansford, Adrian P Stephens (Mobilian Corporation)
Outline • Introduction (5) • Collaborative Mechanism (14) (MAC Layer Solution) • Simulation Result (4) • Conclusion • Reference
Introduction (1/5) • 4 Task Groups • TG1: WPAN/Bluetooth • TG2: Coexistence • TG3: WPAN High Rate • TG4: WPAN Low Rate • 1 Public Committee
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
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
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
Collaborative Mechanism • Introduction • Collaborative Mechanism (14) (MAC Layer Solution) • Simulation Result • Conclusion • Reference
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
Collaborative Mechanism (2/14) • Overall Structure: AWMA Control
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
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
TBTT Collaborative Mechanism (5/14) • AWMA
Collaborative Mechanism (6/14) • Structure of the MEHTA Entity
Local 802.11 Activity Local 802.15.1 Activity Transmit Receive In-band Out-of-band In-band Out-of-band Transmit Transmit None Transmit-Receive or None Transmit-Receive or None Receive Transmit-Receive or None Transmit-Receive or None Receive None Collaborative Mechanism (7/14) • Known Physical-Layer Characteristic • 802.11b pass-band • 802.15 hopping pattern
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
Collaborative Mechanism (9/14) • Known 802.15 States: • Current or expected receive and transmit activity • Channel List • Duration • Time Remaining
Access Mechanism Effect of Tx Confirm(status=denied) DCF The 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 it’s will aggregate collision…) PCF (as CF-pollable STA) No transmission from the STA occurs, and the AP can resume transmission after a PIFS. (But it’s will cause wasting…) PCF as PC No transmission from the AP occurs, and the AP can resume transmission after a PIFS. Collaborative Mechanism (11/14)
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
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.
Simulation Result (4) • Introduction • Collaborative Mechanism (MAC Layer Solution) • Simulation Result • Conclusion • Reference
Experimental Results (1/4) 8 7 6 5 Throughput (Mb/s) 4 Simulation Tool accurately models experimental WLAN / BT performance 3 2 1 0 0 10 20 30 40 50 60 70 80 90 100 Received Signal Power (-dBm) BT=OFF (measured) BT=1m (measured) BT=OFF (simulated) BT=1m (simulated)
Conference Room Usage (2/4) Many stations, each with independent piconets Bluetooth speakerphone As before, aggregate throughput is shared among all users Conference Room Scenario Back to Single User Scenario
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 Office Scenario Back to Single User Scenario
Individual User (4/4) BT headset operating from same laptop as Wi-Fi station Individual Scenario
Conclusion • Introduction • Collaborative Mechanism (MAC Layer Solution) • Simulation Result • Conclusion • Reference
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.
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
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