Geographic Routing Protocol In Wireless Sensor Networks

Geographic routing is widely used in wireless sensor networks. However,the problem that most of the geographic routing algorithms which adopt greedy algorithm as their basic routing strategies have to face is the 'local minimal phenomena'.How to reduce the occurance of local minimal and how to design the recovery strategy with better efficiency,is of great significance in the geographic routing.This paper analyzes the geographic routing algorithms in wireless sensor networks.We discuss concrete algorithms and their performance, characters.Besides,the planarization algorithms which are demanded in parameter routing are generalized and analyzed.This paper presents a new geographic routing algorithm,Greedy algorithm based on the geographic information of 2-hop neighbors (Greedy-2).Greedy-2 algorithm makes nodes be aware of the existence of voids before the packet reaches a region where the Greedy forwarding fails,so that the packet can bypass the dead-end node ahead of time to reduce the probability of encountering the routing voids.PATN,a Planarization Algorithm based on Two-hop Neighbors,is also introduced. PATN ensures the success of perimeter routing through the planarization without extra overhead,and guarantees delivery in UDG networks when Greedy-2 algorithm fails.Extensive simulation further shows that Greedy-2 algorithm can signifcantly decrease the routing void phenomena. It obtains better performance than Greedy algorithm based on 1-hop neighbors in aspects of the packet delivery rate and the length of routing path.GPSR-2,which combines Greedy-2 and PATN algorithms,has less average length of routing path than GPSR.This paper also introduces a new geographic routing algorithm—Greedy based on Blind-area Information Routing,GBIR.This algorithm enables each node to know global blind-area information by local blind-area finding algorithm and exchanging neighbors' blind-area information a few times,routes the packets using greedy combined with the blind-area information to keep away from routing void and escape from the "local minimum phenomena",therefore guarantees reliable data delivery.Extensive simulation of GBIR on NS has been conducted. And the results show its better performance than GPSR in routing path and routing load balance.Finally,the author summarizes the routing void problems and provides discussion on some unresolved problems and development trend in this field.