U.S. Philips Corporation

Richard C Burbidge

David Keith Roberts

Rodney W Gibson

Anthony K Sharpe

Philip Anthony Jamieson

Andrew T Yule

For battery economizing in a receiving station (CU) having a radio identity code (RIC) consisting of M bits, a base station (MIU) transmits a wake-up message consisting of at least two repetitions of a wake-up sequence having N concatenated parts. Each of the N parts includes a sync code word and a different fraction M/N of bits of a radio identity code (RIC). The receiving station is energized intermittently in order to detect carrier and at least one of the N parts. In response to detecting that one of the N parts is received, the receiving station remains energized and analyzes at least the detected one of the N parts. If the received bits of the transmitted radio identity code do not correspond to the corresponding bits of the receiving station's radio identity code, the receiving station reverts to intermittent energization, otherwise it remains energized to receive a message appended to the transmitted radio identity code. Each of the parts may be appended to a different sync code word identifying the part thereby enabling address identification to be carried out on only that one of the parts. The bits of the transmitted radio identity code may be scrambled prior to being fractionalized into the N parts.

Battery economizing in a communications system

A selective call system comprises at least one base station which transmits address code words at a predetermined data rate. High rate telescript information having a length of more than 500 characters, for example, an E-mail message, is transmitted at a data rate greater than that used for sending address code words. In the event of the system comprising a simulcast system, intersymbol interference (ISI) may occur and in order to reduce the effects of ISI on the decoding the telescript information while avoiding an unnecessarily large drain on a secondary station's batteries, the telescript information as received for a specific secondary station is stored and subsequently equalized in non-real time. The secondary station can comprise a mobile terminal unit and may include a transmitter for transmitting acknowledgement or other response signals, for example, such as spread spectrum signals. The acknowledgement signals may be used for locating the mobile terminal unit.

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Basingstoke, United Kingdom

Richard C Burbidge