Connection Admission Control and Comparison of Two Differentiated Resources Allocation Schemes in a Low Earth Orbit LEO Satellite Constellation

The Up/Down Link UDL of a Low Earth Orbit LEO satellite constellation is a scarce radio resource that needs to be shared efficiently between many users with different needs. A suitable Connection Admission Control (CAC) policy is required. In our study we assume that the network handles three types of calls: real time (voice) calls with strict constraints over the delay and over the bandwidth, nonreal time (data) calls delay tolerant but with bandwidth guarantees requirements and Best Effort calls with no guarantees requirements. In order to ensure priorities are respected, two mechanisms are considered: an enhanced extended trunk reservation policy, as well as a combination of trunk reservation with priority scheduling in order to derive the Resources Allocation RA. A differentiated RA scheme is proposed, associated with queuing for the lower priority calls. Different unit bandwidths are associated with calls depending on their requirements. The analytical Markovian models for both the differentiated and the non-differentiated trunk reservation systems are first derived, under simplified hypothesis, in order to point out the advantages of the differentiated RA choice. Then, the model for another RA scheme, the combined differentiated trunk reservation/priority scheduling, is also analytically solved under Markovian hypothesis for the different traffic classes. The performance of the two more general versions of the RA techniques thus solved are compared using simulation. Impact of non-Markovian laws is also studied using simulation.