Abstract: Multiple, different, independent constellations (10, 20) of satellites (2, 21-23) share a portion of a common frequency spectrum such as a single carrier frequency. The satellites' antennas (11) may be either multi-beam or omni-directional, while those of earth stations (13, 14) are directional. When interference occurs between communications of a satellite (31) of a first constellation (10) and a satellite (41) of a second constellation (20), any of several interference-mitigation options may be employed, such as the first satellite (31) handing off communications to a second satellite (32) of the same constellation (10), or temporarily suspending communications. The remedial action may occur in response to either predicted or detected interference.

Abstract: Multiple, different, independent constellations (10, 20) of satellites (2, 21-23) share a portion of a common frequency spectrum such as a single carrier frequency. The satellites' antennas (11) may be either multi-beam or omni-directional, while those of earth stations (13, 14) are directional. When interference occurs between communications of a satellite (31) of a first constellation (10) and a satellite (41) of a second constellation (20), any of several interference-mitigation options may be employed, such as the first satellite (31) handing off communications to a second satellite (32) of the same constellation (10), or temporarily suspending communications. The remedial action may occur in response to either predicted or detected interference.

Abstract: Within a communication system having a plurality of communication system sites, each communication system site has a one cell re-use pattern of a limited number of communication resources. Communication units within the communication system utilize a redundant transmission of information such that the geographic separation of communication system sites utilizing the same communication resources is reduced.

Abstract: Independent communication systems are provided with additional receivers that allow the systems to monitor one another's outbound control signalling channels. Secondary control signalling can be interleaved with the primary control signalling information on this communication resource, which secondary control signalling information is intended for reception and use by the monitoring system.

Abstract: A trunked communication system wherein less than all of the communication units may transmit an identifying data word thereby registering their location to a system controller every time they enter a different coverage area, while the remainder of the communication units do not. The identity of the communication units which operate in each mode is known to the system resource controller in advance. Pre-registration allows the system controller to know the locale of target units in advance when communications to those units is requested. The locale of units that do no pre-register their location are identified through system wide paging. Coordinating the identification of locales of units in both modes permits greater optimization of spectral resources.

Abstract: An improved communication system is disclosed wherein at least one reprogramming station is added to a communication system. The reprogramming station is constructed and arranged to communicate with the subscriber units thereby either reprogramming or regrouping them. The subscribing units receive the reprogramming command and acknowledge individually, altering a memory means until either reprogrammed back to the original state, or to another state. In another mode, the reprogramming station transmits a regrouping command wherein two or more groups are combined to form a super group.