Research On Parallel Transmission Methods Of MAC Layer In Wireless Sensor Networks

In the wireless sensor networks,the wireless resources are very limited,and the MAC protocols have become a research focus as it controls the network channel resources allocation.In the design of the MAC protocols,how to make full use of the limited channel resources to complete more data communications must be considered as much as possible.The traditional single-channel MAC protocols do not allow parallel transmission and some of the classic multi-channel MAC protocols also encountered the control channel bottlenecks.In this paper,in view of the advantages and disadvantages of the existing parallel transmission MAC protocols,methods and strategies to solve the parallel transmission problems are deeply studied.In view of the shortcomings of the OPC method on decisions of parallel communications,an opportunistic concurrency transmission MAC protocol based on geographic location information(OPCLI-MAC)is proposed.In view of the shortcomings of the LPR-MAC protocol on conflict handing of multiple nodes in multiple channels,a multi-channel parallel negotiation MAC protocol based on geographic location information(LPRLI-MAC)is proposed.The OPCLI-MAC protocol proposes an improved local parallel mapping table and a parallel control algorithm.The node location information is added to the mapping table.The distance between nodes could be calculated.The parallel control algorithm is carried out using the distance value to take two steps processing,in the transmitter of the parallel transmission link,through the comparison between the power radius and the distance of nodes,the potential interference problem from the sender of the parallel transmission link to the nodes in the two-hop range is solved to ensure that the ongoing data communications would not be affected;in the receiver of the parallel transmission link,through the comparison between the distances from senders to the receiver,the receiver chooses the nearest sender to communicate with and handles the hidden terminal problems.The LPRLI-MAC protocol proposes an improved neighbor table and a P-persistence algorithm.The node location information is added to the neighbor table.The distances between nodes could be calculated.The P-persistence algorithm gives a new probability calculation formula by using the distance value,the closer the distance,the greater the probability that the node insists on sending,thus the conflicting problem of multiple transmitters is dealt with.Experiments show that the OPCLI-MAC protocol reduces the interferences of the newly launched parallel transmission link to the ongoing data communications,optimizes the parallel transmission communication decision,improves the probability of the parallel transmissions,and improves the channel utilization.The LPRLI-MAC protocol optimizes the calculation of the probability values in the P-persistence algorithm,reduces the probability of data collisions on a single channel at a certain time,optimizes the parallel negotiation strategy of multiple transmitters on multiple channels,reduces the probability of collisions between multiple parallel transmissions and improves the success rate of transmissions.The OPCLI-MAC protocol and the LPRLI-MAC protocol significantly improve the network throughput and reduce the end-to-end delay and energy consumption while implementing parallel transmission under the condition of large scale and high data transmission rate.They can be applied in the single-channel and the multi-channel network environments separately.