Abstract: In a messaging system, message traffic is transmitted on one or more traffic channels T1, T2 and the allocation of groups S1, S2 of receivers to the traffic channels T1, T2 is controlled by information transmitted on a bulletin board channel BB. A predetermined number of frames before a change in the traffic channel allocation, a countdown value is transmitted in the relevant traffic channel T1 and the countdown value is decremented in each subsequent frame. Before the countdown value reaches zero, the groups of receivers S1, S2 retune to the bulletin board channel, receive their new channel allocations and retune to the traffic channel indicated for their group.

Abstract: In a messaging system, message traffic is transmitted on one or more traffic channels T1, T2 and the allocation of groups S1, S2 of receivers to the traffic channels T1, T2 is controlled by information transmitted on a bulletin board channel BB. A predetermined number of frames before a change in the traffic channel allocation, a countdown value is transmitted in the relevant traffic channel T1 and the countdown value is decremented in each subsequent frame. Before the countdown value reaches zero, the groups of receivers S1, S2 retune to the bulletin board channel, receive their new channel allocations and retune to the traffic channel indicated for their group. The frame timings of the different traffic channels T1, T2 are staggered to reduce the peak power required to transmit message bursts in these channels.