Coding and multiple access techniques for data transmission in land-mobile satellite networks

The authors compare the performance of four different multiple access protocols for land mobile satellite data networks. These access schemes are: slotted ALOHA, slow frequency-hopping, and two reservation schemes. A hybrid automatic-repeat-request (ARQ) scheme based on Reed-Solomon codes is used to combat the error bursts resulting from multipath fading and shadowing. The advantages of using symbol interleaving and erasure decoding are discussed. The effect of parameters such as the rate of forward error correction (FEC) code, the guard time, and the error rate on the acknowledgement channel is evaluated