Ultrashort Wave Frequency Hopping Protocol For Ad Hoc Network Time Slot Allocation

The VHF frequency hopping ad hoc network, which combines the advantages of VHF frequency hopping communication and mobile ad hoc network. It is interconnected by self-organization and uses VHF channel and Frequency-hopping system to communicate. The VHF-FH-MANET is a perfect military communication network. It has some advantages, such as long distance communication, strong anti-interference and survival ability, flexible networking. TDMA system has good support for the synchronization of the frequency hopping communication, so most of the VHF frequency hopping radios use TDMA system as the media access control.The VHF-FH-MANET does not have a central infrastructure. As the features of multi-hop transmission and multi-point sharing, the traditional centralized TDMA slot allocation protocol does not apply to the MANET. Because of the low channel speed, long synchronization time and the limit of the shortest packet length, many distributed slot allocation protocol cannot work efficiently in the VHF-FH-MANET. This dissertation first analyzes and summarizes the existing slot allocation protocol of the MANET network, then a new on-demand five phase reservation protocol (OD-FPRP), which is apply to the VHF-FH-MANET, is proposed. OD-FPRP records the state of usage for each slot and exchanges the result to its neighbors in next frame. Then, every node can set a slot use list of its own two-hop domain. When the node needs to use the channel to communicate with others, it will find an available free slot and try to reserve the slot using the method of FPRP. If the reservation is successful, the node can use the slot in the follow-up frame until the communication is end. Once the communication is end, the node will release the slot, so other nodes can reserve the slot again. OD-FPRP can work parallel in the different locations of the network in a distributed way. Compared with existing protocol, the overhead of OD-FPRP is smaller.This dissertation depicts the design concept and work processes of the OD-FPRP and implements the protocol through the OPNET simulation platform. According to the result of the simulation testing in different network environment, OD-FPRP has a better performance than the existing protocol in average throughput and media access delay in the VHF-FH-MANET.