摘要
提出一种在MIMO系统中采用自适应调制实现可变速率多用户分集的方案。这种方案在仅需反馈子信道信噪比的条件下 ,最大化系统的总比特率。在发射端利用随机波束成形矩阵对发射信号进行波束成形 ,并根据‘灌水原理’对不同天线的发射信号进行功率分配 ;接受端对接收信号进行相应的线性处理后 ,估计出子信道的有效信噪比并将其反馈回发射端。发射端根据反馈的信噪比 ,采用比例调度算法选出期望用户。最后 ,在满足一定误码率的条件下 ,对期望用户的子信道进行自适应调制。仿真结果表明 ,当小区内的用户数足够多时 。
An adaptive modulation technique for multiuser MIMO systems with multiuser diversity is proposed. This technique maximizes the sum of the instantaneous bit rate under a target BER constraint by feeding back sub-channel SNRs only. By generating a random transmit beamforming matrix with water-filling configuration, each user estimates and feeds back the effective SNRs for its sub-channels. With each user's sub-channel SNRs, the transmitter then schedules the transmission to one particular selected with proportional fair scheduling algorithm. Finally, adaptive modulation is applied to each sub-channel of the selected user based on the BER constraint. The simulation results show that the throughput of proposed method converges to that of eigen-beamforming when the number of users in a cell is large.
出处
《科学技术与工程》
2004年第4期275-281,共7页
Science Technology and Engineering
基金
国家自然科学基金 ( 60 2 72 0 65 )
吉林大学科学基金资助
