Inter-user interference suppression precoding based on SLNR for multi-user joint transmission in coordinated multi-point system

Joint transmission (JT) allows base stations (BSs) to serve multiple users (UEs) in the same time and frequency resources, wherefore inter-user interference (IUI) will arise. To solve this problem, an inter-user interference suppressed precoding (IUISP) scheme is proposed in this paper. IUISP contains two steps: firstly, we utilize the system degree of freedom to suppress interference generated by the signal of any UE leaking to all others at each BS independently with sharing the linear combination matrixes designed at UEs before precoding; secondly, based on IUI suppression, signal-to-leakage-and-noise ratio (SLNR) criterion is applied to attain better performance. It can be found that IUISP proposed in this paper can't need the channel state information (CSI) interaction between any two BSs in a cooperation cluster. Furthermore, the performance analysis and simulation results show IUISP has application value in noncoherent JT and can improve the system performance.