1. A Straightforward Path Routing in Wireless Ad Hoc Sensor Networks
Zhen Jiang
Comp. Sci. Dept.
West Chester University
Junchao Ma, Wei Lou
Dept. of Computing
The HK Polytechnic University
Jie Wu
College of Computer & Information Sciences
Temple University
8/28/2018
WWASN'09

2. Outline Introduction Our Approaches Experimental Results Conclusion
8/28/2018
WWASN'09

3. Goal A straightforward path in wireless ad-hoc sensor networks (WASNs)
Fewer hops and detours
Faster data delivery
More energy conserved
destination
source
8/28/2018
WWASN'09

4. Problem Local minimum phenomenon (void) Sparse deployment
Physical obstacles
Node failures
Communication jamming
Power exhaustion
Animus interference
block
void
stuck node
destination
source
8/28/2018
WWASN'09

5. Idea Information helps routing to Predict the ‘void’ ahead
Make a slight turn early to sufficiently avoid being blocked
Non-detour routing, i.e., greedy forwarding without perimeter routing
Change forwarding direction only if necessary
To keep the optimality of a straight forwarding
8/28/2018
WWASN'09

6. Task 1 Identification of the affected area of a void
Relative to the positions of the source and the destination
destination
destination
source
destination
source
source
affected area
destination
affected area
Case 1
Case 2
8/28/2018
WWASN'09

7. Task 2 Mutual impact of void areas
Global optimization achieved by neighborhood optimizations
No routing table, flooding, or broadcasting
Routing decision at each intermediate node
Neighbor information collection and distribution
destination
source
area of mutual impact
8/28/2018
WWASN'09

8. What kind of information and how to conduct a forecast?
Challenge
Unstructured WASNs
Hard to ensure whether the forwarding still achievable ahead
destination ?
What kind of information and how to conduct a forecast?
source
8/28/2018
WWASN'09

9. Our Previous Results (Safety Information Model)
Tradeoff between routing adaptivity and structure regularity
Safety information for such a forwarding
Information based forwarding (SLGF routing) to avoid entering detour areas (local minima)
8/28/2018
WWASN'09

10. Our Approaches (Improvement)
Further study the use of safety information
Increase the adaptivity of safety information based routing
Achieve a straightforward path in more routing cases (a new routing algorithm: SLGF2)
8/28/2018
WWASN'09

11. Tradeoff LAR 1 LAR 2 A forwarding with infrastructure in WASNs LAR2:
Forwarding to a neighbor that is closer to the destination
We adopt LAR1
Forwarding limited in the so-called request zone
destination
destination
forwarding candidate
LAR 1
LAR 2
request zone
current node
current node
8/28/2018
WWASN'09

12. Safety Information Inspired by the safety model for 2-D mesh networks
An unsafe area contains nodes that definitely causing routing detour.
Constructed by information exchanges among neighbors only.
8/28/2018
WWASN'09

13. Estimation of Unsafe Area
A local view at each unsafe node of the blocking effect of local minima (i.e., the topology configuration that makes such a node unsafe)
Ultimate description of all LAR1 forwardings from that unsafe node which are blocked by local minima (in any type)
Simple rectangular shape
Constructed with safety information updates, without extra cost
8/28/2018
WWASN'09

14. Details of the Information Construction
Unsafe node
A node without any neighbor in the request zone
A node without any safe neighbor in the request zone
Unsafe area
Connected unsafe nodes
Estimated as a rectangle at an unsafe node.
4 Different types of unsafe status
Due to 4 different types of request zones
8/28/2018
WWASN'09

15. Type-I Safety Information and the Estimation of Unsafe Area
8/28/2018
WWASN'09

16. SLGF2 Routing (new) Three phases conducted in the order
Safe forwarding
Smartly select appropriate safe nodes as forwarding successors to achieve shorter path around unsafe area
Backup path routing
Guarantee a successful path by multiple safe-forwardings to detour around local minima
Perimeter routing
Be able to detect the network disconnection and avoid unnecessary detours
8/28/2018
WWASN'09

17. SLGF2 Routing Cases
8/28/2018
WWASN'09

18. Simulation To verify whether Forwarding routings
LAR1(-) + Safety Info. (-) + Info. based routing (+) is efficient to achieve straightforward path.
Forwarding routings
GF (LAR2 + boundary information)
LGF (LAR1)
SLGF (LAR1 + safety information)
SLGF2 (LAR1 + new use of safety information)
8/28/2018
WWASN'09

19. 8/28/2018
WWASN'09

20. Result Summary # of hops Length of path
LGF < GF < SLGF < SLGF2
Length of path
8/28/2018
WWASN'09

21. Conclusion
New balance point of the tradeoff between routing adaptivity and information model cost
More accurate safety information
Better forwarding routing to achieve more straight path
8/28/2018
WWASN'09

22. Questions?
Thank you!
8/28/2018
WWASN'09