Research On A Low-latency TDMA Protocol In Ad Hoc Networks

A Mobile Ad Hoc Network(MANET)is a wireless distributed network composed of multiple independent and interconnected mobile nodes.Due to the characteristics of convenient deployment,strong anti-destruction,and wide coverage,MANET is applied to military communications,earthquake relief,and other applications.The non-competitive access feature of TDMA(Time Division Multiple Access)can guarantee the terrific quality of service(Qo S)for low-burst services,which causes an extensive application in MANET.However,owing to the diversified development of services,the growing number of bursty services arrive in MANET,and fixed TDMA supplies unstable data transmission and causes large latency.Besides,the reservation TDMA supports bursty services but leads to huge control overhead,which is also tough to support the services with low-latency requirements.Hence,it becomes an urgent problem for TDMA to guarantee the lower control overhead and support the bursty services with lower latency in MANET.This article proposes a Slot Assignment Base on Neighborhood Information and Priority(SA-NIP).This protocol defines the time slot priority table to realize the conflict-free and fast reservation and guarantee the delay requirements of burst services.Firstly,the protocol obtains the time slot information occupied by the interacting neighbor nodes in the control stage.Secondly,the protocol enables nodes to select the best reserved time slot based on the corresponding neighborhood information and priority when reserving a time slot,thereby reducing the probability of reservation conflicts.Further,the protocol takes the neighborhood information and priority as the basis for conflict judgment,provides an efficient and low latency time slot allocation strategy while ensuring the conflict-free time slot allocation,and ensures the fairness of time slot resource allocation.Finally,this protocol gives the node the highest priority in the reserved time slot when reserving time slots for burst services,so that the burst service can quickly occupy a time slot,which reduces the access delay of the burst service.To verify the effectiveness of the SA-NIP protocol,we simulate the SA-NIP by using OPNET.Then we compare the USAP with FPRP under different service loads in the scenarios of chain topology,network topology,and mobile topology.The simulation results validate that SA-NIP can drastically decrease the average network delay and improve the network throughput due to the low-overhead conflict-free reservations.