1. < Sungrae Cho >, <Chung-Ang UNIV>
<September 2008>
doc.: IEEE
Project: IEEE P 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 , Republic of Korea]
Voice:[ ], FAX: [ ],
Re: [Contribution to IEEE 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 P 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 P
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>

2. Reliable Broadcast for WBAN
<September 2008>
doc.: IEEE
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

3. < Sungrae Cho >, <Chung-Ang UNIV>
<September 2008>
doc.: IEEE
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

4. Different Reliable Broadcast Schemes
<September 2008>
doc.: IEEE
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

5. < Sungrae Cho >, <Chung-Ang UNIV>
<September 2008>
doc.: IEEE
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

6. < Sungrae Cho >, <Chung-Ang UNIV>
<September 2008>
doc.: IEEE
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

7. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
TRB (Timer based Reliable Broadcast)
Transmitter Behavior
Transmitter broadcasts data and waits for .
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 expires, the transmitter broadcasts the next data.
If any of the Bit Maps are not set after expires, the transmitter rebroadcasts the data.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 7

8. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
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

9. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
TRB (Timer based Reliable Broadcast) 1 2 7
coordinator 3 4 6 5 8
broadcast
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 9

10. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
TRB (Timer based Reliable Broadcast) 1 2 7
coordinator 3 4 6
broadcast 5 8
Implicitly considered
as anACK
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 10

11. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
TRB (Timer based Reliable Broadcast) 1
coordinator 2
ACK
ACK 7
ACK 3
ACK
ACK
ACK 4 6
ACK 5 8
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 11

12. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
TRB (Timer based Reliable Broadcast) 1
Coordinator 2
ACK
ACK 7
ACK 3
ACK
ACK
ACK 4 6
ACK
ACK 5 8
Collision
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 12

13. TRB (Timer based Reliable Broadcast)
<September 2008>
doc.: IEEE
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

14. Performance Evaluation (1)
<September 2008>
doc.: IEEE
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

15. Performance Evaluation (2)
<September 2008>
doc.: IEEE
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

16. Performance Evaluation (3)
<September 2008>
doc.: IEEE
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

17. Performance Evaluation (4)
<September 2008>
doc.: IEEE
Performance Evaluation (4)
10 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 17

18. Performance Evaluation (5)
<September 2008>
doc.: IEEE
Performance Evaluation (5)
20 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 18

19. Performance Evaluation (6)
<September 2008>
doc.: IEEE
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

20. Performance Evaluation (7)
<September 2008>
doc.: IEEE
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

21. Performance Evaluation (8)
<September 2008>
doc.: IEEE
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

22. Successfully received nodes (%)
<September 2008>
doc.: IEEE
Successfully received nodes (%)
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 22

23. < Sungrae Cho >, <Chung-Ang UNIV>
<September 2008>
doc.: IEEE
Energy Consumption
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 23

24. This work has been supported by HNRC of IITA.
<September 2008>
doc.: IEEE
This work has been supported by HNRC of IITA.
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 24

25. < Sungrae Cho >, <Chung-Ang UNIV>
<September 2008>
doc.: IEEE
Thank You!
<September, 2008>
< Sungrae Cho >, <Chung-Ang UNIV>
Slide 25