New Results on Single User Massive MIMO

*Kasturi Vasudevan, Surendra Kota, Lov Kumar and Himanshu Bhusan Mishra*

### **Abstract**

Achieving high bit rates is the main goal of wireless technologies like 5G and beyond. This translates to obtaining high spectral efficiencies using large number of antennas at the transmitter and receiver (single user massive multiple input multiple output or SU-MMIMO). It is possible to have a large number of antennas in the mobile handset at mm-wave frequencies in the range 30–300 GHz due to the small antenna size. In this work, we investigate the bit-error-rate (BER) performance of SU-MMIMO in two scenarios (a) using serially concatenated turbo code (SCTC) in uncorrelated channel and (b) parallel concatenated turbo code (PCTC) in correlated channel. Computer simulation results indicate that the BER is quite insensitive to retransmissions and wide variations in the number of transmit and receive antennas. Moreover, we have obtained a BER of 10<sup>5</sup> at an average signal-to-interference plus noise ratio (SINR) per bit of just 1.25 dB with 512 transmit and receive antennas (512 512 SU-MMIMO system) with a spectral efficiency of 256 bits/transmission or 256 bits/sec/Hz in an uncorrelated channel. Similar BER results have been obtained for SU-MMIMO using PCTC in correlated channel. A semi-analytic approach to estimating the BER of a turbo code has been derived.

**Keywords:** single user massive multiple input multiple output (SU-MMIMO), Rayleigh fading, serially concatenated turbo code (SCTC), parallel concatenated turbo code (PCTC), spectral efficiency (SE), signal-to-interference plus noise ratio (SINR) per bit, spatial multiplexing, bit-error-rate (BER)
