Efficient resource utilization through carrier grouping for half-duplex communication in GSM-based MEO mobile satellite networks

In the near future, existing terrestrial radio networks are envisioned to integrate with satellite systems in order to provide global coverage. In order to establish communication for both nonhand-held and hand-held user terminals, the radio link design must allow full- and half-duplex operation, respectively, where the latter is desirable when radiation power restrictions are imposed. In addition, due to user mobility and wireless channel volatility, sophisticated resource management is required, so as to enhance system capacity. However, a major inherent problem of the satellite link is propagation delay, which may lead to inefficient resource allocation and reduced spectral efficiency. We address the resource allocation problem that arises in the context of a medium-Earth-orbit (MEO) satellite system with half-duplex communication capabilities. MEO satellite systems are characterized by large propagation delays and large intrabeam delay variations, which are shown to result in resource consumption. We propose a channel classification scheme, in which the available carriers are partitioned into classes and each class is associated with a range of propagation delays to the satellite. The suggested infrastructure results in better channel utilization and reduced call blocking rate and can be implemented with low signaling load.