Research On MAC-PHY Interface Protocol Of LEO Satellite Communication System

With the rapid development of global economy and exchange of information,mankind will also enter the era of personal communication in the future.SLWOP low-orbit satellite mobile communication system currently being studied and designed belongs to the low-orbit broadband satellite communication system and the ground station access side of the user station and gateway station has four layers of protocol:network layer,RLC layer,MAC layer,physical layer.System for the MAC layer and PHY layer protocol was defined in detail,but the communication between the two layers is not involved,so the MAC layer and PHY layer communication problems must be solved for the system.In response to this situation,the main contents and innovations of this paper are as follows:Firstly,the papaer researchs and proposes the MAC-PHY interface protocol based on the SLWOP low-orbit satellite communication system.By studying the structure and framework of the system,the MAC layer and PHY layer structure and protocol functions are analyzed to determine that the MAC-PHY interface is responsible for handling the MAC layer message transmission protocol messages of the SS and the GS of the subscriber station and controlling important functions such as PHY physical layer link processing,further proposes MAC-PHY interface control plane and data plane required functions,proposes based on MAC and PHY frame data encapsulation model.Secondly,the paper establishes the control plane handshake communication mechanism model of SS and GS station and data plane handshake communication mechanism model to establish three kinds of primitives of MAC-PHY interface control plane and data plane,establishes common header and message body structure model.Then the paper proposes the synchronization mechanism of handshake protocol between SS and GS,and numbered each frame to create the control information TransVector,which contains UL-MAP information and MODCOD information of the system physical layer to instruct the assembly of upstream frame and downstream frame,meanwhile,to ensure the order of each frame transmission.The control plane parameter configuration primitives,the start termination primitives,and the data plane transmission start and stop primitives,the reception start and stop primitives,and the contents and functions of the data transmission and reception primitives are designed for the subscriber station SS and the gateway station GS.Thirdly,the paper builds MAC-PHY interface protocol model of OPNET platform.Combining with three node models of user station node,satellite node and gateway station of the system,MAC-PHY interface node,process and state transition of user station SS and gateway station GS are built three-tier model,the establishment of synchronization mechanism model and the mechanism of the queue mechanism,design simulation process flow chart and state transition diagram.Simulation uplink and downlink communication simulation,based on the overall user station SS and the gateway GS via satellite communication process to establish the MAC-PHY interface simulation model validation,and finally it is applied to the location management service,and the MAC-PHY interface protocol is nested into the location paging to simulate the paging success rate,so as to further verify that the MAC-PHY interface protocol designed by the research is feasible.