Design And Implementation Of A Low Power Consumption MAC Protocol In Ad Hoc Networks

An Ad Hoc network is a kind of network with no need of fixed infrastructure and features of rapid deployment,so it can be applied to lots of scenarios.In the Ad Hoc networks that consist of battery-powered nodes,energy consumption decides the network lifetime,and becomes one of the key metrics for measuring network performance.Due to the networking control in a distributed manner and the broadcast characteristic of wireless channels,the performance of the applied Medium Access Control(MAC)protocol becomes a key factor affecting the network lifetime.The MAC protocols with low power consumption that lengthen the network lifetime are studied in this thesis.Of them,the Time Division Multiple Access(TDMA)protocols have certain advantages over other competitive MAC protocols.TDMA protocols can more accurately control the state of the node in future time slots and shorten the unnecessary channel listening time.Moreover,they can also access channel without collision,thereby guaranteeing the successful frame transmission and improving the network throughput.Therefore,in the research of the TDMA protocol with low power consumption,the difficulty is how to allocate and schedule time slots with less overhead under the condition of dynamic topology.Aiming at the power consumption problem of MAC protocol,this paper proposes a low power consumption MAC protocol TLMP(TDMA-based Low power consumption MAC Protocol)based on TDMA.TLMP mainly reduces power consumption in three aspects: First,TLMP dynamically changes the number of available access slots for new incoming nodes,reducing the number of listening slots for nodes in the network when there are no new nodes or only one new node entering the network.Second,based on the fixed allocation time slot,TLMP transfers the remaining time slots of the node to the required neighboring nodes with less overhead and without increasing the number of control information,and completes the time slot redistribution process in the distributed scenario.Finally,when the amount of data transmitted by the node is less than the set threshold,TLMP can also save energy by adjusting the cycle to let the node sleep for a longer period of time.In addition,in order to reduce its own multi-hop transmission delay,TLMP establishes a fast forwarding channel to accelerate the transmission of forwarding data.Based on the OPNET platform,this paper compares and analyzes TLMP and other protocols in both static and mobile environments.Energy consumption,throughput and delay are the three indicators that focus on.The simulation results show that the energy saving effect of TLMP is significant,which the energy consumption is lower than Sensor Medium Access Protocol(S-MAC)with a duty cycle of 20% in many scenarios,and is far lower than Carrier Sense multiple Access/Collision Avoidance(CSMA/CA)protocol.Its throughput is close to the CSMA/CA protocol and is larger than S-MAC.In addition,the allocation protocol TLMP reduces its own multi-hop transmission delay,but due to the existence of the scheduling interval,its delay is still relatively large,which is more suitable for applications that are not sensitive to delay.