Event-based analysis of time diversity at Ka-band with maximal ratio combining

This paper reports on a preliminary study using EutelSat Hotbird 13A (previously known as Hot Bird 6) beacon data at 19.7 GHz and 29.5 GHz (scaled data) to evaluate the benifit of using Time Diversity (TD) and Maximal Ratio Combining (MRC) on an experimental Ka-band (26.5-40 GHz) satellite link in the UK. The benefit of the TD and MRC scheme was measured in terms of percentage enhancement of the link availability. The integration reduces the bit error rate (BER) of the affected data packets during the fades, in order to minimize the link outage. Results were also compared against selection combining (SC). Long-term statistics of rain and atmospheric attenuation were derived from a period of three year's measurements made in Pontypridd, South Wales and in Chilbolton, England, at 19.7 GHz. These were supplemented by meteorological measurements at both sites. A hypothetical Ka-band satellite broadcast link between Pontypridd and Chilbolton has been designed, where the system is configured to use 29.5 GHz as the uplink frequency from Chilbolton while 19.7 GHz is used as the downlink frequency at Pontypridd. The downlink attenuation time series is based entirely on measured data, whereas the synthetic uplink attenuation time series were computed from the measurements at 19.7 GHz using ITU-R frequency scaling formula for rain attenuation. The paper discusses the performance of TD and MRC on the satellite link for 4 different types of fade events, where most of the fading occurs due to intense rain. The integration of TD and MRC provides the capability to continue delivering services at lower carrier-to-noise (C/N) levels by lowering the bit error rate (BER).