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Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 1
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [The Distributed Contention Access Scheme]Date Submitted: [Feb. 20067]Source: [Pei Liu, Liang Li ] Company: [Hisilicom Technology Co. Ltd, Vinno Technologies Inc. ]Address: [Nan Tian Bld., No.10 Xinxi. Rd Shang-Di Information Industry Base, Hai-Dain District, Beijing,China ]Voice:[86-10-82882552], E-Mail:[[email protected], [email protected]]
Re: [This document is an updated version of IEEE 802. 15-06-0462-01-004c]
Abstract: [Description the upgraded MAC issues on Chinese WPAN Standard Draft]
Purpose: [To encourage discussion.]
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(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.
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 2
The Features of WAPN Communication
Low data rate and small packets of a single node
Large number of nodesCSMA/CA mechanism: slotted and unslotted
ones.• It is necessary to optimize the CAP Scheme to
get the better network throughput)• The Feasibility to Optimize the CAP Scheme
(based on the CAP model and calculation method of throughput)
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 3
Promoting Distributed Contention Access
Distributed CAP is promoted to optimize the CAP scheme for:• The channel model within CAP; And • The calculation method of network
throughput; And • The performance of network throughput; And• Efficiency of total energy utilization of network
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 4
The Distributed Contention Access Scheme (1)
• The model of CAP optimization
• The procedure is same as ones in 15.4-2006
optimization of network
calculate the back off number
optimization
get the time parameters
calculate successful CCA probability
get the network parameters
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 5
The Distributed Contention Access Scheme (2)
• The detail CAP optimization steps：1. Get the number of devices in the network
using the CAP channel model.
2. Calculate the back off number to get optimal network throughput.
3. Optimize the device number in CAP period based on the result of 2nd step
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 6
The Distributed Contention Access Scheme (3)
Get the parameters of a cycle
Calculate throughput and average cycle length
Calculate optimal back off number
Calculate the probability of successful CCA
Estimate the device number based on average successful CCA probability
Revise the device number in the every successful CCA cycle
Optimize the network
• Procedure of optimal contention access
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 7
Simulation Results of the CAP Optimization (1)
• Supposed:Some of devices transmit the fixed size packets to the
coordinator simultaneously, andEach device can use the distributed CAP for
optimization. The initial number of devices is 5, and 80s later, some
additional devices are connected into the networkOther conditions strictly pursue the ones in
CSMA/CA procedure in 802.15.4 std
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 8
Simulation Results of the CAP Optimization (2)
• Case 1: 15 additional devices become active
(a) Optimal throughput
simulation time
norm
alliz
ed th
roug
hput
simulation time
norm
alliz
ed th
roug
hput
(b) 15.4's throughput
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 9
Simulation Results of the CAP Optimization (3)
• Case 2: 35 additional devices become active
(a) Optimal throughput
simulation time
norm
alliz
ed th
roug
hput
simulation time
norm
alliz
ed th
roug
hput
(b) 15.4's throughput
Feb. 2007 doc:IEEE802.15-07-0610-00-004c
Slide 10
Simulation Summary Though the calculating method for parameters of CAP is
optimized, but the procedure, format and parameters of optimized CAP are same as the 15.4-2006
By the CAP optimization from Distributed Contention Access, the throughput of network will reach a new stable optimal value after short-lived fluctuation, even though the device number changes sharply
By the optimization of CAP and throughput, the efficiency of total energy utilization of WPAN is improved.
