Reference Signals Power Allocation for Uplink MU-MIMO in LTE System

In this paper, an efficient power allocation scheme of reference signals (RS) for uplink MU-MIMO in LTE system is introduced. In LTE system, some virtual subcarriers at the borders of the allocated bandwidth are used which invalidates the conventional power allocation schemes for uniformly placed reference signal. Further, RS for multiuser are multiplexed by cyclic shift. Constant power is required within one step of cyclic shift which adds more constraint on power allocation. The proposed RS power allocation scheme minimizes the mean square error (MSE) of the least square (LS) estimates considering the effect of virtual subcarriers and the constraint due to the cyclic shift. The effectiveness of the proposed scheme is verified by simulation results, showing that 2 dB SNR gain is achieved as opposed to conventional scheme with equal power reference signal.