Improving QoS of Satellite Broadcasting Against Rain Attenuation by LLR Sharing Method With IP Network Integration at FEC Layer

We are developing a diverse reception system (DRS) to compensate for rain attenuation in satellite broadcasting that utilizes path diversity between a satellite channel and a best-effort (BE)-IP network for end users. The proposed DRS recovers signals lost on a satellite channel due to significant rain attenuation by supplementing them via a BE-IP network. The unique point of the DRS is that it uses a common forward error correction (FEC) for both channels by applying a FEC for satellite broadcasting to the error correction in BE-IP network. This allows both channels to be integrated at the FEC layer and improves the quality of service (QoS) in the satellite broadcasting thanks to sharing the decoding information between the two. In this paper, we propose an advanced error-correction technique that achieves a high QoS in the DRS by sharing each log-likelihood ratio (LLR) utilized for the FEC decoding of bits received over both channels. This technique, which we call the LLR sharing method, enables successful error correction even when neither a satellite channel nor a BE-IP network can individually achieve error-free transmission due to significant rain attenuation or burst packet loss, respectively. Computer simulation results confirm that the LLR sharing method can improve the required C/N in the satellite broadcasting. In addition, we discuss how to suppress the load of the BE-IP network and integrate both channels efficiently.