  In this paper we propose the introduction of adaptive hybrid automatic repeat
request (HARQ) in the context of mobile satellite communications. HARQ schemes
which are commonly used in terrestrial links, can be adapted to improve the
throughput for delay tolerant services. The proposed method uses the estimation
of the mutual information between the received and the sent symbols, in order
to estimate the number of bits necessary to decode the message at next
transmission. We evaluate the performance of our method by simulating a land
mobile satellite (LMS) channel. We compare our results with the static HARQ
scheme, showing that our adaptive retransmission technique has better
efficiency while keeping an acceptable delay for services.
