短波地空IP网络的MAC协议设计与仿真

DESIGN AND SIMULATION OF HIGH FREQUENCY GROUND-TO-AIR IP NETWORK MAC PROTOCOL

合适的多址接入MAC(multiple access)协议是提升网络性能的关键。根据短波地空IP网络通信覆盖范围广、难同步,空中节点信息可能丢失的特点,设计出该网络一种新型的带预约短波令牌协议HFTP-R(High Frequency token protocol with reserve)。该协议在初始化时由空中节点随机加入地面节点形成的簇,并通过预约信道向地面节点发送预约信息,从而获取令牌接入信道,地空之间不需要保持逻辑环的"封闭性"。最后,利用OPNET软件构建了HFTP-R的仿真框架,与其他MAC协议作了仿真比较。仿真结果表明,HFTP-R减少了短波令牌协议HFTP(High Frequency token protocol)的令牌丢失次数和传递开销,能提供较好的实时性、较高的网络吞吐量和业务传输成功率,在特定需求下较其他MAC协议更有优势,可满足网络需要。

Appropriate multiple access（ MAC） protocol is the key to promoting the performance of network. The high frequency（ HF）ground-to-air IP network has a large communication coverage area and is hard to get synchronisation,and the air node＇s data may lose.According these characteristics,we design a novel high frequency token protocol with reserve（ HFTP-R） for the network. In its initialisation,the protocol forms the cluster by the air nodes randomly joining in the ground nodes,meanwhile sending reserve data to ground nodes through the reserve channel so that to get the token to access the channel,which doesn＇t need to keep the closure property of logical ring between the air and the ground. Finally,we developed the simulation framework of HFTP-R by OPNET,and compared it with several other MAC protocols in simulation. Simulation results show that,HFTP-R decreases the token loss counts and token passing overhead of high frequency token protocol（ HFTP）,offers better real-time quality,higher network throughput and success rate of traffic transmitting,and has more advantage than other MAC protocols in some scenarios,which meets the requirement of networks.