Algorithm Research For GEOCAST Routing Protocol Improvement Over Wireless Network

Since the widely use of cell phone and laptop has encouraged the fast developing of ad hoc network technology, one important research focuses on the data transmission algorithms in ad hoc network. The GEOCAST protocol based on the geographic location is one of the crucial parts of data transmission algorithms. GEOCAST is a scalable, low overhead technique for building mobile ad hoc wireless networks. By using geographic locations to route packets, GEOCAST can make purely local decision to route packets, avoiding the routing protocol overhead by other ad hoc routing protocols in large networks. This thesis mainly studies some related algorithms on GEOCAST improvement algorithms in mobile ad hoc networks.This thesis firstly introduces general development and some techniques of GEOCAST protocol, analysis and evaluates the original GEOCAST protocols. Under different criterions, some simulations have been made to compare the performances. By theory and experiment analysis mentioned above, this thesis summarizes some factors that affect GEOCAST performance over wireless network.Then a GEOCAST routing protocol based on former analysis is proposed. According to the position of mobile nodes, the proposed protocol divides the flooding of control packets into two parts: nodes in the forwarding zone transmit control packets by flooding, nodes out of the forwarding zone transmit packets with directed data transmission algorithm. The simulation results show that the new protocol improves the performance in good-put ratio and send delay in sparse ad hoc network.In addition, this thesis proposes a new GEOCAST protocol for vehicle network (GRVN). Mobile nodes using this new algorithm automatically decide the GEOCAST nodes and forwarding zone according to the position, speed and the direction. Data is transmitted in two directions. The simulation results show that GRVN can improve the performance of data transmission in highway ad hoc network.Finally, this thesis studies the GEOMULTICAST protocol. By combining the directed GEOCAST routing protocol with the multicast protocols, we proposed two simple GEOMULTICAST algorithms based on multicast tree and mesh distinguishingly. The experiments show that they can get good performance with overhead under control.