10 Gbps 8×8 MIMO-OFDM Broadband Experimental System for 11 GHz Band Super High Bit-Rate Mobile Communications

Super high bit-rate mobile communications have been investigated to achieve more than 10 Gbps bitrate, and 5 Gbps 4 × 4 MIMO-OFDM experimental system has been developed. This paper presents a 10 Gbps 8 × 8 MIMO-OFDM experimental system that consists of baseband (BB) circuits supporting 400 MHz bandwidth and 11 GHz band radio frequency (RF) circuits. The BB circuits employ newly developed 800 MHz-sampling ADC circuits, and a BB calibration method compensates for different phases of clock signals provided into ADCs by using an interpolation filter. In addition, the RF circuits are expanded to eight channels, and a RF calibration method copes with IQ imbalance. Transmission performances are evaluated by the 10 Gbps 8 × 8 MIMO-OFDM experimental system employing turbo detection. It is shown that SNR degradation of the experimental results can be limited to 0.4 dB compared to the simulation results, and that the experimental system can achieve 10 Gbps throughput at SNR = 15.9 dB by three iterations of the turbo detection.