The Design And Test Of A Low-power TDMA Protocol In MANETs

A Mobile Ad hoc Network(MANET) is a special kind of wireless mobile communication network that does not need fixed infrastructures. A MANET is composed of a group of devices with wireless transceiver and can establish communication platform quickly. In some application scenarios, these mobile nodes are powered by battery, so how to save energy is a problem which can't be ignored. On the other hand, the protocols and algorithms in the Ad Hoc network are different from those in a traditional mobile communication network, which is decided by its unique characteristics. CSMA is a common random media access protocol, and it makes packets suffer from long access delay because of a large number of collisions under the condition of heavy load. Compared to CSMA,TDMA protocol has a good throughput performance in this situation, so it has become a hot research direction.With the growth of the micro-electronics industry and the progress in the FPGA field, SOPC is gradually becoming the new research focus of embedded systems. Not only it runs fast and occupies less resources, but also has a small size and low power consumption. It is suitable for the power sensitive equipment in self-organized network. Consequently, A SOPC system including a Microblaze soft core based on the Xilinx's Spartan-6 FPGA chip is designed, and it can support the transmission of real-time voice in a multi-hop MANET.Firstly, some SOPC related technology and the whole hardware platform are briefly described. Secondly, the research status of the MAC protocol are discussed concisely. Finally, considering the requirement for low power consumption in our special scenario, a novel MAC algorithm for Ad Hoc Network--BLP-TDMA(Broadcast Low Power Time Division Multiple Access) is presented. Compared with the traditional TDMA algorithm, BLP-TDMA has abandoned the mechanism to send the control frame regularly and replace it with another scheme which will acquire the necessary information by broadcasting the control information in the data packet in the first stage and implement the optimization of slot assignment in the next stage. To obtain the information of the adjacent nodes and leaf nodes within two hops, flooding will be implemented three times in the first stage. In the optimization of slot assignment stage, the slot of all the nodes that need transfer the business will be expanded synchronously or kept the same.In the last, this paper simulates and verifies the correction and efficiency of the BLP-TDMA by designing a simulation scenario where the information exchange between the multi nodes is modeled by multi process communication in LINUX environment. The result shows that the overhead of the BLP-TDMA protocol is smaller and it consumes less power compared with the traditional TDMA protocols which send the control frame regularly.