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MIMO无线传输技术极大地提高了系统的容量.在实际通信系统中,整个网络是一个干扰受限的系统,小区间干扰对MIMO系统传输的影响是显著的,每个相邻小区的基站天线都可以看成一个干扰源.由于基站端数据处理能力的提升和回程容量的增加,多个小区协同多点传输技术引起了人们的广泛关注.目前的大部分工作都是集中于研究系统的容量(吞吐量),而在实际系统中,每个用户的接收等效信噪比(即公平性)对系统的性能如误帧率等有重要的影响.对于每个用户为单天线的情形,研究了总功率受限和每天线功率受限下采用迫零预编码的系统容量和公平性.对两种功率约束条件下的公平性进行了分析,得到了公平性算法的闭式表达式.当每个用户为多天线的情形,为了降低计算的复杂度,引入了信道范数最大的接收天线选择算法,把每个用户为多天线的情形转化成等效的每个用户单天线情形,推导的每用户为单天线的公平性算法仍然适用.仿真结果显示,采用迫零预编码的多小区协作可以使系统性能显著提升.在相同的迫零预编码下,不同的功率分配策略对系统的容量和公平性有显著的影响.和用户为单天线相比,采用天线选择算法可以提升系统的容量和公平性.考虑了用户公平性时的吞吐量和最大系统吞吐量之间的折中关系,并给出了仿真结果.
MIMO wireless transmission technology greatly improves the capacity of the system.In the actual communication system, the entire network is a system with limited interference and the impact of inter-cell interference on the transmission of the MIMO system is significant. The base station antenna of each neighboring cell has Can be seen as a source of interference.Because of the improvement of data processing capabilities and the increase of backhaul capacity at the base station side, coordinated multi-point transmission technology of multiple cells has aroused widespread concern.Most of the current work focuses on the capacity of the system Throughput), whereas in a real system, the reception equivalent SNR of each user (ie, fairness) has a significant impact on system performance such as frame error rate, etc. For the case where each user is a single antenna, The system capacity and fairness using zero-forcing precoding with limited total power and limited line power are analyzed.The fairness under the two power constraints is analyzed and the closed-form expression of the fairness algorithm is obtained. In the case of multiple antennas for each user, in order to reduce the computational complexity, a receiving antenna selection algorithm with the largest channel norm is introduced to convert each user into multiple antennas into equivalent In the case of single-antenna, the fairness algorithm derived from single-antenna per user is still valid. Simulation results show that the system performance can be significantly improved by using multi-cell cooperation with zero-forcing precoding. Under the same zero-forcing precoding, The power allocation strategy has a significant impact on the capacity and fairness of the system.As compared with the single antenna, the antenna selection algorithm can improve the capacity and fairness of the system.Considering the user throughput and the maximum system throughput The relationship between the compromise, and gives the simulation results.