Performance analysis for a guaranteed handover service in an LEO constellation with a "satellite-fixed cell" system

Abstract

Abstract-It is anticipated that the satellite component of the future universal mobile telecommunications system (UMTS) will be based (partly or totally) on non-GEOstationary (non-GEO) constellations of satellites to serve mixed populations of users, each category being treated through different contracts stipulating different quality of service (QoS). In particular, we envisage a high-quality premium service which guarantees the success of each handover procedure, called guaranteed handover (GH) service, and a low-cost lower quality service called regular service, where handover failures are accepted provided that the probability of a call being unsuccessful does not exceed a given value. This paper proposes a strategy which eliminates forced call terminations due to handover failures, thus allowing the GH service. This procedure applies to low earth orbit (LEO) constellations using the satellite-fixed cell technique. An analytical model has been derived to calculate QoS parameters for a mixed population of GH and regular users. Providing both GH service to some users and regular service to other users requires an increased satellite capacity with respect to the case where all the users are served with the regular service; this capacity increase has been evaluated as a function of the percentage of GH users, the traffic load per cell, and the considered satellite mobility environment. The GH approach has been validated through the comparison with another scheme which envisages the queuing of handover requests for privileged users.

Analytic study of doppler-based handover management in LEO satellite systems

“…Let us consider the simplified case where a cell is approximated by the rectangle in Fig.1, an assumption widely used in the literature ( [2], [3], [6]). DDBHP defines a time interval, called time threshold (t T H ), prior to handover occurrence.…”

“…In order to derive a model for the analytical study of the proposed method, the concept of "street of coverage" [14], [2], [6] is adopted. It refers to a region covered by satellites in the same orbital plane and can be extended to represent a succession of cells ( [6]).…”

“…In this case although no delay is imposed, a cautious planning is needed to avoid an undesirable increase of blocking probability. In [6] G. Maral et al proposed a guaranteed handover service (GH) in systems where channels are fixed allocated to cells. According to the proposed method calls requesting the guaranteed handover service are admitted in the network only if a free channel exists both in the serving and in the next cell.…”

“…The reservation may be predetermined (guard channels- [4], [5]) or based on a prediction of handover requests [6]- [7]. Especially in [7] handover management is considered as part of an end-to-end routing protocol.…”

Satellite handover techniques for LEO networks

“…In [2] a guaranteed handover service was proposed. According to this method a new call is admitted in the network only if there is an available channel in the current cell and simultaneously in the first transit cell.…”