In this paper, we propose a channel reservation mechanism referred
to as time-based channel reservation algorithm (TCRA). The aim of TCRA
is to handle the handover issue in low Earth orbit satellite networks.
These systems face an important number of handover attempts due to the
high satellite velocity when placed in low orbits. The TCRA scheme uses
the deterministic satellite movement pattern to estimate the user
residence time in each cell to be crossed. Two versions of the algorithm
are proposed depending on whether the network disposes of a positioning
system or not. These versions of TCRA allow to guarantee a null handover
failure probability for the users. The performance of TCRA (with its two
versions) is examined by simulations and compared to the guard channel
scheme. The results show the behaviour of the schemes and their
performance in terms of new call and handover blocking probabilities
"It is apparent that the algorithm necessitates satellites with integrated positioning facilities. In  another version of that algorithm was proposed for constellations where a positioning system is not available. "
[Show abstract][Hide abstract] ABSTRACT: Low earth orbit (LEO) satellite systems gained considerable interest towards the end of the previous decade by virtue of some of the appealing features that are endowed with, such as low propagation delay and the ability to communicate with handheld terminals. However, after the limited commercial success of the flrst networks of this kind, future satellite net- works are now conceived as complementary rather than competitive to terrestrial networks. In this paper, we focus on one of the most in∞uential factors in system performance, that is, the handover of a call. First, we provide a succinct review of the handover strategies that have been proposed in the literature. Then we propose two difierent satellite handover tech- niques for broadband LEO satellite systems that capitalize upon the satellite diversity that a system may provide. The proposed schemes cater for multimedia tra-c and are based on the queuing of handover requests. Moreover, a deallocation scheme is also proposed according to which capacity reservation requests are countermanded when the capacity that they strive to reserve is unlikely to be used. Simulation studies further document and conflrm the positive characteristics of the proposed handover schemes.
Telecommunication Systems 08/2006; 32(4):225-245. DOI:10.1007/s11235-006-9000-6 · 0.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Specifying Satellite handover procedures are proposed for investigating the satellite diversity (namely, the existing common coverage area between contiguous satellites) of some satellite constellations in order to provide an efficient handover strategy and QoS in multimedia applications. Based always on a tradeoff of the blocking and forced termination probabilities three different handover criteria are examined for the appropriate selection of the servicing satellite. Each criterion can be applied either to new or handover calls, therefore we investigate nine different service schemes. Extended simulation results provide a deep insight on the system operation and lead to a beneficiary system architecture.
[Show abstract][Hide abstract] ABSTRACT: Due to the high mobility of low earth orbit (LEO) satellites, there is a significant number of handover attempts in a LEO satellite mobile communication system, causing a high handover failure rate. This paper proposes an Adaptive Channel Reservation Scheme (ACRS) which gives an overall optimal success rate for both handover and new call initialisation. ACRS is able to adapt to the local traffic condition and makes the best decision on the timing of sending out a channel reservation request. A simulation model has been built and tested on uneven traffic density condition. Promising results have been obtained and they agree with theoretical expectation.
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