矿井巷道时频编码协作MC-CDMA自适应功率分配128教程.doc

PAGE 8 PAGE 2 矿井巷道时频编码协作MC-CDMA自适应功率分配 许晶晶，杨维，张琳园 （北京交通大学 电子信息工程学院，北京 100044） 摘要：矿井巷道时频编码协作MC-CDMA无线传输可有效改善矿井巷道中用户的无线通信性能。矿井巷道时频编码协作MC-CDMA无线传输当目标用户与协作伙伴的发送功率之和为定值时，因目标用户、协作伙伴与基站间的信道增益会随用户位置变化而变化，在目标用户和协作伙伴间采用等功率分配方案会造成功率资源的浪费。为充分利用有限的功率，保证目标用户的无线通信性能，在目标用户、协作伙伴和基站处设置接收信噪比门限，目标用户功率对总功率的功率分配比例ρ需满足目标用户、协作伙伴和基站接收的信噪比高于该接收信噪比门限。推导出了矿井巷道时频编码协作MC-CDMA功率分配比例范围，并取分配比例范围的中间值作为目标用户与协作伙伴之间的功率分配比例。推导结果显示，功率分配比例随总功率和平均信道增益变化而变化，从而在用户位置改变或总功率变化时能动态地为目标用户和协作伙伴分配功率，实现了功率的自适应分配。仿真结果表明，与等功率分配方案及其他自适应功率分配方案相比，无论是目标用户位置变化还是总功率变化，采用所提出的自适应功率分配方案显著地减小了矿井巷道时频编码协作MC-CDMA目标用户误比特率性能。 关键词：矿井巷道；编码协作；多载波码分多址；自适应功率分配 中图分类号：TD65+5 文献标识码：A Adaptive power allocation for time-frequency coded cooperation MC-CDMA system in mine tunnel XU Jingjing, YANG Wei, ZHANG Linyuan (School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China) Abstract: Time-frequency coded cooperation MC-CDMA improves the performance of wireless transmission of mine tunnel effectively. The sum of transmission power of the target user and collaborative partner is a fixed value in the system. As the channel gains among target user, collaborative partner and base station vary with the changes of the location of users, the equal power allocation scheme between target user and collaborative partner for the time-frequency coded cooperation MC-CDMA may result in the waste of power resource. In order to make full use of the limited power and ensure the performance of wireless communication of target users, a SNR (signal-to-noise ratio) threshold at the target user,?collaborative partner and?base station?is set up. It should be guaranteed that the received SNRs at the target user,?collaborative partner and?base station are larger than the threshold with the power distribution ratio ρ which is the power of target user to that of total power. The range of power distribution ratio for the time-frequency coded cooperation MC-CDMA is deduced, and the median value of the range is taken as