Research On The Dynamic Slot Ssignment Algorithm Based On TDMA Ad Hoc Networks

With the development of information technology, people hope a variety of needsfrom the network. Ad hoc networks are different from the traditional networks withinfrastructure, the node is not only a terminal but also a server. Ad hoc networks hassignificant features such as multi-hop communication, distributed control andself-organization, so it has attracted the attention of many researchers, for more than40years of development, the researchers studied much about Ad hoc networks, anddevelop or improve the protocols. These research promote the Ad hoc networks’development and application.At present, the research of Ad hoc networks across multiple areas, including theadaptive technology in physical layer, MAC protocols, routing protocols, QoS assuranceand security issues, especially for the channel access protocols, researchers haveproposed dozens of specialized protocols for Ad hoc networks, most of them base oncompetitive class, such as the widely used802.11DCF. In terms of the competitiveprotocols, when the network’s load increases, the probability of collisions will graduallyincrease, and that will have an influence to throughput, and the channel access delayalso increases, it is difficult to ensure the real-time, but on the other hand, accessprotocol of assign class can be better, therefore, the research about the assignment classchannel access protocol for Ad hoc network is a hotspot.This paper focus on TDMA dynamic slot assignment algorithm, called dynamicTDMA protocol, we introduce two typical dynamic TDMA protocol in detail, FPRP andE-TDMA, for E-TDMA protocol, its time slots allocation based on the dimension of theload of nodes, but it does not take the nodes’priority. In real networks, especially in themilitary networks, the E-TDMA protocol can’t fit the network, for example, somenodes’ traffic in the network is little, but the traffic is important, these nodes need highpriority to ensure the information’ transmission. Therefore, we propose the PE-TDMAbased on the nodes’ priority to improve the E-TDMA protocol, and analysis theprotocol on priority processing.We have set different simulation scenarios in OPNET Modeler, and we set thesimulation in two groups, one is PE-TDMA protocol comparison E-TDMA protocol,and PE-TDMA protocol comparison CSMA/CA protocol. We can get that PE-TDMAprotocol can improve channel utilization in the simulation compared to CSMA/CA,PE-TDMA protocol also maintain a small media access delay time, particularly thenetwork has high load, the PE-TDMA protocol access delay time is much smaller thanthe CSMA/CA, and the PE-TDMA protocol has greater throughput too.