Abstract: An apparatus and method for optimizing multiple access satellite and terrestrial mobile communications network performance using random access or multiple access protocols such as frequency division multiple access (FDMA), random access, code division multiple access (CDMA), or optimally, time division multiple access (TDMA) protocols. Performance is optimized through the use of persistence algorithms in congestion control methods for random access channels in such a network, whereby mobile terminal participation is eliminated from the congestion control procedure. In one aspect, a fixed network dynamically directs the operation of a mobile terminal-based persistence algorithm using only locally derived information which is directly transformed into an accurate estimate of random access channel throughput.

Abstract: A method and apparatus for determining the proper satellite communications service to be provided to a subscriber unit that may be integrated with the geographically defined service areas used in terrestrial cellular communications systems. The pre-existing geographically defined service areas are subdivided into quadrilateral tiles wherein each tile corresponds to a single service area. In addition, the tiles are mapped to a grid having a plurality of regularly spaced grid locations. A lookup table is created that references each grid location to the tiles that overlap the grid locations. The position of the subscriber unit and an approximated region of error within which the subscriber unit is likely to be located are used as input. The approximated region of error is mapped to the grid to identify the grid locations that align with the approximated region of error.

Abstract: A method and apparatus for predicting when to perform spot beam and satellite handover in a mobile satellite communication network that uses the position of the mobile subscriber. The method and apparatus perform all calculations with respect to a satellite-based coordinate system, thereby eliminating the need to model the shape of the geometrically complex spot beams on the surface of the earth. The position of a mobile subscriber unit that initiates a call is tracked relative to a set of spot beam boundaries that are located equidistant between a first spot beam within which the subscriber unit is located at the time of call initiation and a set of adjacent spot beams. An interval during which the subscriber unit will cross over one of the boundaries is estimated.