Development and performance evaluation of MMSE macrodiversity reception system with delay difference correction

We have been developing a minimum-mean-square-error macrodiversity (MMSE-MD) reception system using distributed remote antennas and radio-on-fiber (RoF) links for use in live broadcasts of road races. The system selects remote antennas with good signal quality and combines their signals based on the MMSE algorithm to combat both small-scale and large-scale fading. For the system to be feasible, we have to consider propagation delay differences among diversity branches due to the RoF links and radio propagation. This paper describes a practical delay difference correction (DDC) technique that can keep signal continuity in any situation, the hardware implementation of an MMSE-MD receiver embodying the technique, and indoor and outdoor performance evaluations. Our prototype receiver perfectly corrected the propagation delay differences among diversity branches without losing signal continuity and maintained MD reception without signal outage across a wide area on an actual road-race course.