Adaptive modulation and coding for satellite-UMTS

An adaptive coding and modulation transmission scheme applicable for third-generation mobile satellite systems is proposed. The transmitter dynamically selects the optimum coding and modulation scheme according to the environment in order to maximize the spectrum and power efficiency. A constant average bit error rate (BER) is maintained without changing (or with a very small change to) the transmitted power, and hence the scheme eases the power control requirements. In addition, a higher throughput can be achieved compared to fixed (non-adaptive) systems. Unlike other adaptive transmission systems, in our work the adaptation is based on the Rice factor. The paper also discusses a Rice factor estimation algorithm.