一种多用户多输入多输出系统下行链路线性预编码方法

Research on a Linear Precoding Method of Multiuser Multiple-Input Multiple-Output Downlink Systems

针对多用户多输入多输出系统下行链路线性预编码的信干噪比最大化方法中,共信道干扰抑制和噪声抑制不能有效平衡的问题,提出将其中的噪声方差项修正为以噪声方差为变量的分段线性函数的改进方案.该方案通过对噪声方差项的分段修正,在噪声方差的值较小时依然能够保持共信道干扰抑制和噪声抑制间的平衡,从而使系统的误比特率性能和容量得到进一步提高.仿真结果表明,与信干噪比最大化法相比,所提方案对于基站天线数为5、移动用户数为3、移动用户天线数均为2的多用户系统,在平均误比特率为10-4水平上可以获得2 dB的性能增益,当信噪比为10dB时,可以使系统的各态历经容量增加1 b.(s.Hz)-1.

For the problem that the suppression of cochannel interference and suppression of noise can＇t be balanced in signal-to-jamming and noise ratio （SJNR） maximization method for the linear precoding of multiuser multiple-input multiple-output （MIMO） downlink systems, an improved scheme that the term of noise variance is modified as a piecewise linear function is proposed, in which the balance between suppression of co-channel interference and suppression of noise can still be maintained even when the noise variance is a small value through piecewise mod- ifying the term of noise variance, and thus the bit error rate and capacity of the systems are further improved. Simulation results show that compared with the SJNR method, for a multiuser MIMO downlink system with five base station antennas and three mobile users with two antennas for each, the proposed scheme can obtain 2 dB gains when the average bit error rate is at 10^- 4 level, and the ergodic capacity can be increased by 1 b · （s · Hz）^-1 if signal-tonoise ratio is 10 dB.