Abstract: In a wireless communications system, transceivers transmit short bursts to a base station, which determines timing corrections from the time of receipt of the burst and transmits the timing corrections to the respective transceivers. In one aspect, the base station indicates to the transceivers a plurality of time slots, each transceiver selects one of the time slots at random, formats a burst including an indicator of the selected time slot and transmits the burst in that slot. In another aspect, the base station transmits to each transceiver a timing uncertainty value, which determines how the timing correction will be modified by the tranceiver as the interval since last receiving a timing correction increases. Data bursts are transmitted in a format comprising a first unique word, a content field and a second unique word, in that order. The bursts are transmitted in a TDMA channel format which can accommodate both short and long bursts in a block format of constant periodicity.

Abstract: In a wireless communications system, transceivers transmit short bursts to a base station, which determines timing corrections from the time of receipt of the burst and transmits the timing corrections to the respective transceivers. In one aspect, the base station indicates to the transceivers a plurality of time slots, each transceiver selects one of the time slots at random, formats a burst including an indicator of the selected time slot and transmits the burst in that slot. In another aspect, the base station transmits to each transceiver a timing uncertainty value, which determines how the timing correction will be modified by the tranceiver as the interval since last receiving a timing correction increases. Data bursts are transmitted in a format comprising a first unique word, a content field and a second unique word, in that order. The bursts are transmitted in a TDMA channel format which can accommodate both short and long bursts in a block format of constant periodicity.

Abstract: In a wireless communications system, transceivers transmit short bursts to a base station, which determines timing corrections from the time of receipt of the burst and transmits the timing corrections to the respective transceivers. In one aspect, the base station indicates to the transceivers a plurality of time slots, each transceiver selects one of the time slots at random, formats a burst including an Indicator of the selected time slot and transmits the burst in that slot. In another aspect, the base station transmits to each transceiver a timing uncertainty value, which determines how the timing correction will be modified by the tranceiver as the interval since last receiving a timing correction increases. Data bursts are transmitted in a format comprising a first unique word, a content field and a second unique word, in that order. The bursts are transmitted in a TDMA channel format which can accommodate both short and long bursts in a block format of constant periodicity.

Abstract: A radio frequency paging service has one or more TDMA return channels (R) in which terminals (14) acknowledge receipt of messages having an acknowledge flag set. In one alternative, slots are allocated in the return channel (R) by a slot allocation field in the respective messages. In another alternative, each terminal (14) monitors the messages addressed to other terminals (14) to determine which of them require a response, and determines, from the order of a message addressed to itself among the messages requiring a response, which slot to use for acknowledgement. The TDMA return channels (R) include unreserved slots which terminals (14) access on a contention basis. The frequencies of transmissions in the slots are randomized within a predefined limit to reduce the probability of interference between different terminals (14) in the same unreserved slot. The predefined limit is based on the maximum differential Doppler shift between terminals (14).

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.