Geometry-based forwarding and broadcast schemes for wireless sensor networks

We propose geometry-based forwarding schemes using location information as well as a broadcast scheme in wireless networks. For reliability, many existing geographic forwarding schemes use an RTS/CTS-based approach but when the size of data delivered is small, the overall overhead in terms of energy consumption and delay of such schemes can be high. Besides, routing holes are significant obstacles to the geographic forwarding. Another issue with the existing approaches is that throughput of the geographic forwarding schemes is limited due to multiple transmissions on a single channel. To improve throughput, many multi-channel switching protocols have also been proposed but in those existing schemes, there is the high overhead caused by sequential channel negotiation in a hop-by-hop manner. In addition, in the channel negotiation, the channel information within three hops which is important to reduce interference, is not considered.;To tackle the first issue, we propose a simple and yet efficient geographic forwarding scheme capable of bypassing routing holes, called Angled relaying with Backoff time and (relay) Cancellation (ABC). ABC is a message based (or non RTS/CTS-based) scheme using implicit acknowledge and has its routing hole bypassing mechanism which is a reactive and soft-state based approach. Based on ABC, to solve the second issue, we propose a new multi-channel geographic forwarding scheme, called Angled relaying with Backoff time and (relay) Cancelation scheme using Multiple Channels (ABC-MC). ABC-MC utilizes a novel channel pre-negotiation mechanism to improve the end-to-end delay and the channel usage within three hops to reduce interference.;We also propose a constant approximation broadcasting algorithm using geometric property. In wireless networks, to solve the broadcast storm problem, many broadcasting protocols have been proposed. However, since their work was based on only collision model without considering the interference ranges, those broadcasting protocols may no longer be applicable to practical problems. Thus, we propose a collision-free and interference-free broadcasting algorithm called Interference Aware Broadcast algorithm (IAB). When the interference range is twice as large as the transmission range, the approximation ratio we achieved is 26.