Research And Development On Multiple Service Access Technology In Wireless Ad Hoc Networks

The Ad Hoc network was originally mainly used in the military field.Now it is beginning to tilt toward civilian use,such as field research,environmental monitoring,medical monitoring,and smart homes.With the increasing number of multimedia application scenarios today,how to solve the fast,efficient,and stable transmission of multimedia services in Ad Hoc becomes an important research topic.The performance of the MAC layer access protocol directly affects the service quality of service(Qo S)and data transmission efficiency.This article focuses on MAC multiple access,and studies the multi-service access technology that supports service quality.Firstly,in the protocol design studied in this dissertation,the links between nodes are singlechannel wireless links,and the nodes have the same status and no central control node.Then the dissertation has a deeper study of various classical MAC access protocols,including the competition,distribution and hybrid protocols,comparing advantages and disadvantages,and makeing an in-depth analysis of the EDCA mechanism that supports Qo S.The classic backoff algorithm and mechanism are briefly introduced at the same time.Secondly,combining the actual application environment and functional requirements of the project,taking into account the different levels of sensitivity of different services to bandwidth,delay,and bit error rate,the dissertation designs a hybrid access method,including enhanced CSMA/CA based on competing DCF,distribution-based TDMA,and dynamic TDMA reservation.and utilize the enhanced distributed channel access EDCA to support business service quality.At the same time,the dissertation elaborates the steps of its design and implementation in several aspects such as the overall framework of the protocol,time slot frame structure,access control module,backoff mechanism,synchronization scheme and Qo S control.Finally,simulation of slot synchronization,collision detection and channel access model of EDCA mechanism is completed on the OMNe T++ platform.The specific access protocol is implemented using SDL mechanism in Visual Studio.The joint testing of protocols and physical layers was performed on the channel simulator and multi-node test platform.And debugging of the access protocol was completed on the Zynq-7030 hardware platform.Through the joint design and debugging of software and hardware,the effectiveness of the multi-service hybrid access protocol in this dissertation is verified and the requirements of system engineering practice are satisfied.