Abstract: In a cellular communication system an out-of-lock secondary station scans the physical channels of each of the respective carrier channels in order to find a carrier channel onto which to lock. In order to expedite such scanning, the secondary station follows a scanning sequence such that each scan is of consecutive physical channels of one of a series of non-adjacent carrier channels. Due to spill-over of transmitted beacon signals which may be present in the non-scanned adjoining carrier channels, it is possible during each scan to detect the presence of beacon signals in an adjoining non-scanned carrier channel as well as in the scanned channel. This achieves more rapid identification of an available physical channel in a carrier channel selected by the secondary station, thereby reducing the time to establish lock-on and so saving battery power.

Abstract: A communication system such as a digital cordless telephone system comprises primary (or base) stations (PS) and secondary stations (SS). The primary stations over a local area are coupled to a system controller (14 or 15) which interfaces with the PSTN. A TDMA method is used for forward and reverse transmissions between a primary and a secondary station. For digitized speech transmission normally one duplex voice channel formed by one forward time slot (or physical channel) and one reverse time slot (or physical channel) in each frame is allocated for the transaction. For fast data rates it is desirable that additional duplex voice channels be made available quickly for the transmission of a fast data message, after which the additional duplex voice channels can be relinquished. In order to facilitate the rapid set-up of a data transaction, a map store in each data secondary station lists the usage and quality of all the duplex voice channels.

Abstract: A method of, and system for, data transmission over a time division duplex channel in which at least one duplex voice channel constituted by a pair of non-adjacent time slots (or physical channels) in a succession of time frames is allocated for effecting a data transaction between a first and a second station, one of said pair of time slots (or physical channels) being normally designated for unidirectional transmission of data in a first direction between the first and second stations and the other of the pair of time slots (or physical channels) being normally designated for unidirectional transmission of data in a second direction, opposite to the first direction.