Transcript 슬라이드 1

<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Reliable Broadcast for WBAN]
Date Submitted: [September, 2008]
Source: [Sungrae Cho, Wonsuk Choi, Xiangbo Zhang, Laihyuk Park and Dong Dong]
[School of Computer Science and Engineering, Chung-Ang University ]
Address [221 Heukseok, Dongjak, Seoul 156-756, Republic of Korea]
Voice:[+82-2-820-5766], FAX: [+82-2-820-5766], E-Mail:[[email protected]]
Re: [Contribution to IEEE 802.15.6 Meeting, September 2008]
Abstract: [This document is a summary of the proposed Timer-based Reliable Broadcast (TRB) for
WBAN networks.]
Purpose: [Contribution]
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.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 1
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Reliable Broadcast for WBAN
Sungrae Cho, Wonsuk Choi, Xiangbo Zhang, Laihyuk Park, and
Dong Dong
UC LAB
Chung-Ang University
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 2
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Introduction
• Why reliable broadcast is needed?
– Sometimes medical emergency event occurs in
WBAN and needs to be broadcast to entire
network reliably.
– Some control information needs to be delivered to
entire network reliably.
– S/W update needs to be done reliably
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 3
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doc.: IEEE 802. 15-08-0688-00-0006
Different Reliable Broadcast Schemes
• Simple Flooding: it starts with a source node
broadcasting a frame to all neighbors. Each of
neighbors in turn forwards the frame to all its
neighbors exactly one time and this continues
until all reachable network nodes have
received the frame.
• NAK-based: receivers respond with only
negative acknowledgments.
• ACK-based: more reliable scheme where the
transmitter waits for all ACKs from the
receivers until it transmits the next frame
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 4
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doc.: IEEE 802. 15-08-0688-00-0006
MOTIVATION (1/2)
• Suppose that every receiver node acknowledges for
broadcast data, e.g.,
• The broadcast node will be overwhelmed by
acknowledge messages (a.k.a. implosion problem).
• This acknowledgments are generated almost
simultaneously if no control enforced.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 5
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doc.: IEEE 802. 15-08-0688-00-0006
MOTIVATION (2/2)
• This implosion problem also causes the
problems of
– Unnecessary Collision
– Unnecessary Power Consumption
• Solution: randomize the transmission of the
ACKs
• How?:
– Use timers
– Implicit ACK (reduce the # of acks)
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 6
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doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
• Transmitter Behavior
– Transmitter broadcasts data and waits for D T .
– Transmitter maintains a Bit Map indicating whether
it received an ACK from a particular one-hop
neighbor.
– If the Bit Maps are all set (Tx received all ACKs)
before D T expires, the transmitter broadcasts the
next data.
– If any of the Bit Maps are not set after D T expires,
the transmitter rebroadcasts the data.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 7
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doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
• Receiver Behavior (after receiving broadcast data)
– On successful receipt of broadcast data, each
receiver acts as a transmitter by broadcasting the
data using random timer DR.
– This timer randomizes transmission of the received
broadcast data.
– One of the transmissions is considered to be an
implicit ACK to the original broadcaster.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 8
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doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
1
2
7
coordinator
3
4
6
5
8
<September, 2008>
broadcast
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 9
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
1
7
2
coordinator
3
4
6
broadcast
5
8
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Implicitly considered
as anACK
Slide 10
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doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
1
ACK
7
coordinator
2
ACK
ACK
ACK
3
ACK
6
ACK
ACK
4
5
8
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 11
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doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
1
ACK
7
Coordinator
2
ACK
ACK
ACK
3
ACK
ACK
6
ACK
4
ACK
5
8
Collision
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 12
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doc.: IEEE 802. 15-08-0688-00-0006
TRB (Timer based Reliable Broadcast)
1
coordinator
2
7
3
4
6
broadcast
5
8
Random timer
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 13
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doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (1)
Simulations Setup
• Results
•
-- 10 nodes
•
-- 20 nodes
•
-- 30 nodes
•
-- 40 nodes
•
-- 50 nodes
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 14
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doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (2)
Experimental setup
•
•
•
•
•
Simulation platform: NS2 + LR-WPAN
# of nodes: Variable
Neighbor distance: 7 m ~ 11m
Tx range: 12 m
PAN Coordinator (PC): bottom node (or
designated node)
• Network startup:
– PC starts at: 0.0
– Any other node starts at: random time between 1.0 and 3.0
•
Frame error rate : 10%
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 15
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doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (3)
Measured
• Successfully received nodes (%): we
collected # of nodes that received the frame
successfully per each frame. Then, the
percent of successfully received nodes is
calculated as the ratio of # of successfully
received nodes to entire # of nodes.
• Energy consumption: average # of
transmissions of a frame as an energy
budget.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 16
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doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (4)
10 nodes : Reliable Broadcasting
Parent ID
[18]
25
Node ID
PAN Coordinator
Node having associ
ated and being leaf
node
Node having asso
ciated and being
coordinator
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 17
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (5)
20 nodes : Reliable Broadcasting
Parent ID
[18]
25
Node ID
PAN Coordinator
Node having associ
ated and being leaf
node
Node having asso
ciated and being
coordinator
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 18
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (6)
30 nodes : Reliable Broadcasting
Parent ID
[18]
25
Node ID
PAN Coordinator
Node having
associated and
being leaf node
Node having
associated and
being coordinator
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 19
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (7)
40 nodes : Reliable Broadcasting
Parent ID
[18]
25
Node ID
PAN Coordinator
Node having
associated and
being leaf node
Node having
associated and
being coordinator
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 20
<September 2008>
doc.: IEEE 802. 15-08-0688-00-0006
Performance Evaluation (8)
50 nodes : Reliable Broadcasting
Parent ID
[18]
25
Node ID
PAN Coordinator
Node having
associated and
being leaf node
Node having
associated and
being coordinator
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 21
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doc.: IEEE 802. 15-08-0688-00-0006
Successfully received nodes (%)
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 22
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doc.: IEEE 802. 15-08-0688-00-0006
Energy Consumption
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 23
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doc.: IEEE 802. 15-08-0688-00-0006
This work has been supported
by HNRC of IITA.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 24
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doc.: IEEE 802. 15-08-0688-00-0006
Thank You!
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 25