CAJ | 학술논문

本文主要在认知系统下研究最优功率分配问题，其中主用户和非主用户共享同一频谱资源。在本系统中主用户基于多天线技术，而非主用户基于MIMO-OFDM技术。利用信道感知技术可以使非主用户首先监听主用户的传输信息，其次估计从主用户到非主用户的正交空间。不同于之前的关于 MIMO 认知系统中信道感知技术的研究，本文首次把 OFDM 技术引入MIMO 认知系统中并在本系统中考虑非理想信道估计问题。然而由于信道估计误差，估计信道和实际信道之间有误差，使得从非主用户到主用户终端的干扰没有完全消除。然后本文提出了一种有效的算法，使得我们得到了在保证主用户QoS下最大化非主用户吞吐量的最优的功率分配。仿真结果描述了非主用户的发射功率约束和主用户的干扰功率约束以及非主用户的吞吐量之间的影响。
본문주요재인지계통하연구최우공솔분배문제，기중주용호화비주용호공향동일빈보자원。재본계통중주용호기우다천선기술，이비주용호기우MIMO-OFDM기술。이용신도감지기술가이사비주용호수선감은주용호적전수신식，기차고계종주용호도비주용호적정교공간。불동우지전적관우 MIMO 인지계통중신도감지기술적연구，본문수차파 OFDM 기술인입MIMO 인지계통중병재본계통중고필비이상신도고계문제。연이유우신도고계오차，고계신도화실제신도지간유오차，사득종비주용호도주용호종단적간우몰유완전소제。연후본문제출료일충유효적산법，사득아문득도료재보증주용호QoS하최대화비주용호탄토량적최우적공솔분배。방진결과묘술료비주용호적발사공솔약속화주용호적간우공솔약속이급비주용호적탄토량지간적영향。
This paper is concerned with the optimal power allocation strategy in cognitive radio systems for a cognitive radio (CR) link under spectrum sharing with an existing primary radio (PR) link. The PR is equipped with multi antennas and the CR is in orthogonal frequency division multiplexing (OFDM) based multiple input multiple output (MIMO) cognitive radio systems. It is assumed that in channel learning scheme, CR transmitter first listens to PR transmission and then estimates the spaces that are orthogonal to the channels from PR. Unlike prior study on channel learning in MIMO based cognitive radio systems, this paper is first to bring the OFDM technology to MIMO based cognitive radio systems and consider the imperfect channel learning. Owning to the channel estimation errors, the interference from CR transmitter to PR terminals cannot be canceled completely. Moreover, an effective algorithm is proposed, and we get the optimal power allocation to maximize CR throughput in precondition of assuring PR QoS. Simulation results show the relations among the CR transmit power constraint, the interference power constraint at PR and CR throughput.