Abstract :
A signaling, supervision and radio technique suitable for multi-channel access in the VHF MTS band is proposed. The logic is based on the continued use of 600/1500 cps transitional signaling and certain existing methods of transmitting supervisory signals to the base terminal. Mobile identification is provided but is neither required or excluded. The availability of a mobile radio equipment which does not detriorate as a result of continuous channel switching is assumed. Signaling tone at either frequency is used to mark the idle channel on which the next call will appear or on which the mobile may seize the terminal. If the mobile is not locked on a channel marked idle, the busy indication is given. The logic of this technique is further detailed in a Table and is illustrated by tracing sequences of calls including special cases such as carrier fade, simultaneous seizure and the persistent caller with no answer. To illustrate feasibility a suitable mobile decoder and control unit is described which provides decoding, supervision and logical control. Component content of this design is tabulated. A possible configuration of a preferred mobile radio transceiver is proposed which employs synthesis type channel switching, linear detection and full duplex operation. The 13 crystals employed are shared by transmitter and receiver and only one is a high accuracy type. It is the object of this paper to encourage the adoption of a multi-channel access standard to serve the interval preceding the development of the broad band service by showing compatibility with existing technique and the feasibility of the required equipment.
