U.S. Philips Corporation

Philips Kommunikations Industrie Ag

Werner Schmidt

Christoph Grauel

Ludwig Kittel

Ulrich Wellens

In a communications system with a plurality of subscriber stations independent from each other, where each subscriber station can access according to a multiple access method a joint duplex transmission channel, the probability becomes very large for simultaneous attempts to get access and thereby the probability of signal destruction becomes particularly large. In order to avoid a blockage of the service channel each subscriber station occupies the duplex transmission channel with a short access signal for initiating a transmission starting with the subscriber station. The subscriber station characterized by the position in time and/or the information contents of the signalling short designation call is thereupon invited by the central base station to provide complete identification information.

Accessing of transmission channels of a communication system

In a communications system with a plurality of subscriber stations independent of each other, where each subscriber station can access a joint duplex transmission channel according to a multiple access method, the probability of simultaneous attempts to get access becomes very image, and thereby the probability of signal destruction is particularly increased. In order to avoid a blockage of the service channel each subscriber station occupies the duplex transmission channel with a short access signal for initiating a transmission starting from the subscriber station. The subscriber station characterized by the position in time and/or the information contents of the short access signal is thereupon invited by the central base station to emit an access signal to join practical access to the communication exchange.

In a two-way radio transmission system, a fixed base station transmits and receives over at least one communication channel a plurality of messages for different types of receivers (TGAx) used in different services (DY). The base station transmits an organization data flow identifying the message type (TGAx) and services (DY). A plurality of different subscriber transmitter receiver sets receive each message type (TGAx) and transmits messages to the base station. The receiver sets decode the organizational data flow, and process only those messages and services which are associated with a given message and service type. In this way, different classes of communication services may be offered, using a common base station.

Integrated-services radio transmission system

A method and apparatus for use in a digital radio transmission system comprising stationary radio stations arranged in a cellular network and to which are assigned a plurality of mobile radio stations. Transmission of digital messages from a stationary radio station to the mobile radio stations assigned to it is effected by wide-band code division multiplex modulation, and transmission of digital messages from such mobile radio stations to the stationary radio station is effected by narrow-band frequency multiplex modulation. This reduces bandwidth requirements and improves the signal-to-noise ratio for each direction of transmission.

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Heroldsberg, Germany

Werner Schmidt