Northern Telecom Limited

British Telecommunications Public Limited Company

International Standard Electric Corporation

Kenwood Corporation

Gpt Limited

Orbitel Mobile Communications Limited

At&t Wireless Communications Products Limited

Brian A Bidwell

Ian A Vance

Nigel Everard Barnes

Peter N Proctor

Andrew Bud

Michael T Dudek

David C Odhams

Rupert Goodings

Malcolm Crisp

Michael John Woodley

Ian Rodgers

David F Leevers

Colin Jeffrey

A communication procedure suitable for a cordless telephone system involves time division duplex radio communication between a handset 11 and a base station 3 using alternating bursts of transmission over a single radio channel. Once a radio link has been set up, initial transmissions carry a synchronisation logical channel S and a signalling logical channel D multiplexed together, but the link may switch to bursts carrying a communications logical channel B for the speech data and the signalling logical channel D. Burst synchronisation is achieved by the asynchronous detection of words in a synchronisation channel S. These words have bit patterns reducing the probability of incorrect asynchronous detection of them. If one part ceases to receive handset signals from the other, it transmits a special signal, informing the other part. This enables both parts to detect the failure of a link at substantially the same time, so that their actions to re-establish the link are synchronised.

Time division duplex telecommunication system

A method of synchronizing a digital radio pager receiver with incoming digital data signals. At switch-on the receiver first attains a 'course' bit synch during the first quarter-word period and then a 'fine' bit synch during the next half-word period. The receiver then examines incoming data bits to determine simultaneously (a) whether valid data is being received and (b) whether the incoming data contains a preamble sequence. If either determination is successful the incoming data is then examined to determine whether it contains a synchronizing word or an address word. The synchronization and address word determination is also carried out while bit synch is obtained and the valid data/preamble determination is effected.

Synchronization of digital radio pager

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Luton, United Kingdom

Brian A Bidwell