A video signal coding device is provided with unit dividing means (202) for dividing an input picture into units each of which is a coding quantity control unit consisting of one or a plurality of frames to be processed by any one of intra-frame coding, inter-frame forward coding, and inter-frame bidirectional coding; activity calculating means (203) for calculating a frame activity for every frame of the input picture, and calculating a unit activity for every unit from the frame activities of frames belonging to the same unit; target coding quantity deciding means (205) for deciding a target coding quantity of a coding frame on the basis of the frame activity of the coding frame which is a coding object, the unit activity of a coding unit to which the coding unit belongs, and the average unit activity of a unit prior to the coding unit; and coding means (206) for coding the coding frame by the target coding quantity so as to generate coded data.
To address the need for a dispatch mobile (303, 305, 307) to more quickly make a call, in the preferred embodiment of the present invention those remote units operating in a dispatch mode (303, 305, 307) will receive a first slot cycle, while those remote units not operating in a dispatch mode (302, 304, 306, 308) will receive a second slot cycle. The second slot cycle is greater than the first slot cycle, so that those remote units operating in dispatch mode (303, 305, 307) will "wake up" during the slot cycle normally utilized for interconnect calls. Because shorter slot cycles are utilized for remote units operating in dispatch mode (303, 305, 307), the time it takes to make a dispatch call is greatly reduced. Additionally the minimum slot cycle duration typically used for standard calls remains unchanged, greatly conserving battery life.
