Post on 29-Mar-2015
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 (4/5)Presenter Title Non- / Collaborative Author Classification
NIST 802.11b Deterministic Frequency Nulling Collaborative R.E. Van Dyck PHY -- OptionMobilian Method for Coexistence Collaborative J. Lansford Time Domain SchedulingSymbol TDMA of BT and 802.11 Collaborative S. Shellhammer Time Domain Scheduling
TI
Proposal for Collaborative Bluetooth and802.11b MAC Mechanisms for Enhancing
Coexistence Collaborative J. Liang Time Domain Scheduling
TIProposal for Non-Collaborative BluetoothMechanisms for Enhancing coexistence Non-Collaborative J. Liang Adaptive Packet Selection, Scheduling
NISTPower Control and Packet Scheduling for
Bluetooth Non-Collaborative N. Golmie Scheduling, Power Control (PC)
Bandspeed Adaptive Frequency Hopping Non-Collaborative H. Gan, B. Treister AFH -- Adaptive Frequency HoppingIPC, Inc. Selective Hopping for Hit Avoidance Non-Collaborative K.C. Chen AFH, Scheduling
TI Proposal for Intelligent Bluetooth Frequency
Hopping for Enhancing Coexistence Non-CollaborativeA. Batra, J. M. Ho,K. Anim-Appiah AFH
TI Power Control for Enhanced Coexistence Non-Collaborative O. Eliezer AFH
TIProposal for 802.11b Power Control for
Enhancing Coexistence Non-Collaborative M. ShoemakePower Control (PC), Data Rate Scaling(DRS)
Combined proposal
Combined proposal
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:
802.11MAC
802.15.1 LM+ LC
802.11 PLCP+ PHY
802.15.1Baseband
TDMAControl
MEHTAControl
Status Status
Tx Enable Tx Enable
Tx Confirm(status)
Tx Confirm(status)
Tx RequestTx Request
CollaborativeCoexistenceMechanism
802.11 Stack 802.15.1 Stack
AWMAControl
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
Collaborative Mechanism (5/14)
AWMA
W P A N In te rv a lW L A N In te rv a l
T B T T
M ed iu mF ree
T ru e
F a lse
W P A N In te rv a lW L A N In te rv a l
BT
W LA NT W P A NT
T B T T
1T
TBTT
Collaborative Mechanism (6/14)
Structure of the MEHTA Entity
802.11MAC
802.15.1 LM+ LC
802.11 PLCP+ PHY
802.15.1Baseband
802.15.1Control
Status Status
Tx Confirm(status)
Tx Confirm(status)
Tx Request
Tx Request
MEHTAControl
802.11 Stack 802.15.1 Stack
802.11Control
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
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 (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
CurrentCollision? Yes
No
Tx Request
Denied
Yes
FutureCollision?
802.15.1Future slotpriority >
802.11 packetpriority ?
Yes Yes
No
Allowed
No
No Yes
No
802.15.1Current slot
priority >802.11 packet
priority ?
Is 802.15.1Currently
Transmitting?
Decision Logic for 802.11 Tx Request
Collaborative Mechanism (11/14)
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.
Decision Logic for 802.15 Tx Request
Responseor
SCO?
Yes
Collision?
802.11current state
priority >802.15.1 packet
priority ?
Yes
No
No
Collision?Slave SlotCollision?
no
NoNo
Tx Request
Allowed
Denied
Yes Yes
Yes
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
0
1
2
3
4
5
6
7
8
0 10 20 30 40 50 60 70 80 90 100Received Signal Power (-dBm)
Th
rou
gh
pu
t (M
b/s
)
BT=OFF (measured) BT=1m (measured)
BT=OFF (simulated) BT=1m (simulated)
Simulation Tool accurately models
experimental WLAN / BT performance
Experimental Results (1/4)
Conference Room Usage (2/4)
Many stations, each with independent piconets
Bluetooth speakerphone As before, aggregate
throughput is shared among all users
0
1
2
3
4
5
6
7
8
1 10 100 1000
Distance from AP (m)
WL
AN
Th
rou
gh
pu
t (M
b/s
)
no interference non TR TR
Back to Single User Scenario
Conference Room ScenarioConference Room 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
0
1
2
3
4
5
6
7
8
1 10 100
Distance frpom AP (m)
WL
AN
Th
rou
gh
pu
t (M
b/s
)
no interference non TR TR
Back to Single User Scenario
Office ScenarioOffice Scenario
Individual User (4/4)
BT headset operating from same laptop as Wi-Fi station
0
1
2
3
4
5
6
7
8
1 10 100 1000
Distance from AP (m)
WL
AN
Th
rou
gh
pu
t (M
b/s
)
no interference non TR TR
Individual ScenarioIndividual 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