1. MMLAB NETWORK SEMINAR
Tree-Based Data Broadcast in IEEE and ZigBee Networks
Written by
Gang Ding(Purdue Univ.), Zafer Sahinoglu(MERL), Philip Orlik(MERL), Jinyun Zhang(MERL), Bharat Bhargava(Purdue Univ.)
Presented by Chang, Dukhyun

2. Contents Introduction Background Proposed Algorithms
& ZigBee Networks
Proposed Algorithms
ZigBee On-Tree Self-Pruning Algorithms
ZigBee On-Tree Selection Algorithms
Performance Evaluations
Conclusion

3. Introduction Broadcasting in Ad hoc Networks Flooding
-> broadcasting storm problem
Finding minimum forwarding nodes
-> NP hard
Some heuristic algorithms
algorithms based on greedy forward node selection
algorithms assuming extra info (location, 2-hop neighbor info)
-> inefficient or not practical in ZigBee Networks

4. Introduction Characteristics of ZigBee Networks
limited computation and storage capacity
no sophisticated algorithms
small size & low cost
no accurate location info.
low data rate & low power
no exchanging large neighbor info
Motivated to find localized and light-weight broadcast algorithm

5. & ZigBee Networks
Device Types
FFD, RDD
Network Structure

6. 802.15.4 & ZigBee Networks Routing
Tree Routing
AODVjr
Forming tree structure with assigning address
An = Aparent + Cskipx(n-1) + n (n≥1)
Cskip

7. 802.15.4 & ZigBee Networks Assigning address No Routing tables !
if Cskip= 21 when d=0
Current Broadcasting in ZigBee Networks
only tree neigbors rebroadcast
A0=0
No Routing tables !
A0=1
A0=22

8. ZigBee On-Tree Self-Pruning
Motivation
General Self-Pruning (a Scalable Broadcast Algorithm(SBA))
rebroadcasting after random period
if all neighbors of a node v(=N(v)) are covered, no rebroadcasting
must receive packets from N(v)
2-hop neighbor info is assumed
need to exchange neighbor info.
-> not practical in ZigBee networks
ZigBee On-Tree Self-Pruning
using light info.
tree structure info.
1-hop neighbor’s address
1-hop neighbor’s # of children
when node u is a neighbor node of node v
we cannot know N(u) but on-tree neighbor of node u(=TN(u))

9. ZigBee On-Tree Self-Pruning
ZigBee On-Tree Self-Pruning Algorithm
rebroadcasting after random period
if all On-Tree neighbors of a node v(=TN(v)) are covered, no rebroadcasting
can know coverage rapidly using TN(u)

10. ZigBee On-Tree Selection
Goal
Find the smallest node set subset F(v)
s.t. F(v) is subset of N(v) to on-tree cover TN(N(v))
Motivation
no 2-hop neighbor info. -> using on-tree neighbor info.
solves problem in polynomial time (OOS)
solves problem with polynomial memory (ZOS)
cover the whole network
Consider covering TN(N(v)) -> trade-off!

11. ZigBee On-Tree Selection
Optimal On-Tree Selection Algorithm
Candidate forward nodes of v
To-be-covered nodes of A

12. ZigBee On-Tree Selection
Example
compare with greedy algorithm (Ad Hoc Broadcast Protocol(AHBP))

13. Performance Evaluation
an event-driven simulator in MATLAB
100m x 100m
Comparison
Scalable Broadcast Algorithm(SBA)
Ad Hoc Broadcast Protocol(AHBP)
ZigBee broadcast algorithm currently used
Global algorithm (global network topology is known)

14. Performance Evaluation
Physical topology
ZigBee topology
ZigBee(100)
SBA(85)
OSR(51)
AHBP(36)
ZOS(31)
Global(10)

15. Performance Evaluation
The number of rebroadcasting nodes
Coverage time

16. Performance Evaluation
Average duplicated packets

17. Conclusion
Given only phisical 1-hop neighbor & logical tree neighbors, this paper two roadcast algorithms for IEEE & ZigBee networks
the on-tree self –pruning rebroadcast algorithm
the ZigBee on-tree selection algorithm, ZOS
The proposed schemes outperform other schemes
These schemes are feasible in computation complexity & memory space complexity