Fixed-point implementation of interpolation-based MMSE MIMO detector in joint transmission scenario for LTE-A wireless standard

The quality of service for the cell-edge users is degraded by inter-cell interference, preventing fulfillment of the LTE-A requirements. The effects of the cell-edge interference can be suppressed by Coordinated Multi-Point (CoMP) transmission/reception techniques. One approach of CoMP in downlink scenario is joint transmission (JT), which is closely related to MIMO communication concept. This leads to incorporation of conventional MIMO detectors for JT. MIMO tone by tone detection demands an extensive computational power. Recently, interpolation based MMSE MIMO detectors have been proposed to reduce the computational power. In this work, the recently proposed floating-point interpolation based MMSE detector is modified to make it suitable for fixed-point implementation. The optimal word-length is determined by simulation-based optimization. The proposed algorithm is implemented on a Virtex-7 FPGA and achieves a clock frequency of 422 MHz, with an optimal word-length of 20 bits. The throughput of the implemented detector exceeds 1.15 Gbps with 0.6 μs latency.