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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

SLGF2 Routing Cases 8/28/2018 WWASN'09

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

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

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

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