| 摘要: |
| 传统中低轨小卫星群的移动自组织网络中，卫星采用半双工载波侦听/碰撞规避协议（Carrier Sensing Multi-access/Collision Avoidance,CSMA/CA）接入控制信道。为避免半双工模式“盲听”对碰撞感知存在的延时，提升接入效率，卫星需要工作在碰撞检测和数据接收同步进行的全双工模式；同时由于卫星通信特点，残余自干扰带来的不完美碰撞检测不可忽略。针对以上需求，设计了一种全双工CSMA/CA协议，对接入流程和参数进行了详细描述；研究了自干扰抑制度和检测门限等与虚警率、漏检率的数学关系；推导了系统吞吐量的解析表达式，并仿真探究了初始竞争窗口长度等参数的优化设计准则。仿真结果表明，通过合理选取参数，该协议能在存有不完美碰撞检测的情况下，实现吞吐量的提升。 |
| 关键词: 低轨卫星群；移动自组织网；载波侦听/碰撞规避协议(CSMA/CA) 不完美碰撞检测 |
| DOI： |
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| 基金项目: |
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| Throughout analysis of CSMA/CA with imperfect collision detection |
| YU Wei,MA Song,LI Cheng,MA Xu |
| (Southwest China Institute of Electronic Technology,Chengdu 610036,China;Department of Electronic Engineering,Shanghai Jiaotong University,Shanghai 200240,China;Beijing Satellite Navigation Center,Beijing 100094,China) |
| Abstract: |
| Satellites access the signaling channel with half-duplex(HD) carrier sensing multi-access/collision avoidance(CSMA/CA) protocol in traditional mobile ad hoc network(MANET) of miniaturized low Earth orbit(LEO) satellite group.Full-duplex(FD) transmission mode should be used in order to avoid the delayed collision detection introduced by the “blind sensing”(half-duplex),and to promote the efficiency of access.By full-duplex technique,satellites are able to do carrier sensing at the same time of receiving messages.Meanwhile,the collision detection is often imperfect due to the residual self-interference(RSI) because of some features of satellite communications.For the above needs,a full-duplex CSMA/CA protocol is designed,whose access process and some key parameters are discussed in detail.The relationship between RSI suppression,the collision detection threshold and the probability of false alarm and miss detection is analyzed mathematically.The closed-form expression of throughput performance is derived,and the influence of some key parameters,such as the initial contention window,is shown in simulation results.From the simulation results,with proper parameters the proposed FD protocol is able to achieve better throughput performance compared with traditional HD CSMA/CA protocol in the case of imperfect collision detection. |
| Key words: LEO satellite group mobile ad hoc network(MANET) carrier sensing multi-access/collision avoidance(CSMA/CA) imperfect collision detection |
《电讯技术》编辑部 