Channel assignment technique for Satellite Mobile Radio Talk-group (SMRT) over MSS band

This paper analyzes the channel assignment protocols for a satellite mobile radio talk-group over S-band Mobile Satellite Services (MSS). The service enables a closed group of mobile radio users to communicate among them, such that a transmission from any user is received by all. A key issue in the design is the efficient allocation of a satellite channel. Satellite telephony uses demand assignment multiple access technique to allocate channels from pool of channels to the users on demand during conversations sessions. Owing to the unique characteristics of the point-to-multipoint group communications where a satellite channel is shared among users, a new protocol technique is required for such a talk-group service. Unlike terrestrial push-to-talk, satellite talk-group exhibits long round-trip delay and encounters channel errors for signaling. Controlled channel access with carrier detection and queued signaling protocols are discussed to arbitrate access contentions so as to improve the utilization of the talk-group satellite channel.