TRANSMISSION METHOD IN A RADIO COMMUNICATIONS SYSTEM COMPRISING SEVERAL TRANSMIT AND RECEIVE BRANCHES IN THE BASE STATION

摘要

The invention relates to a radio communications system comprising a base station and a plurality of subscriber stations. Said system uses DS CDM/CDMA with embedded TDM/TDMA and TDD. The base station comprises at least two independent transmit and receive branches and achieves transmit and receive diversity. Various diversity methods are used in the downlink direction for specific data types: an orthogonal transmit diversity (OTD) is used for the preamble symbols of timeslots; a space time transmit diversity (STTD) is used for the data of a broadcast channel (BCH); and traffic data is emitted individually for each subscriber station via a respective transmit branch, which has been identified as the most suitable by the subscriber station. Various diversity methods are also used in the uplink direction: maximum ratio combining is used for data of a random access channels (RACH), (a phase-corrected addition of the receive values of all receive branches); selective combining is used for the preamble symbols of the timeslots (utilisation of the most powerful receive values); and traffic data is only decoded in the receive branch that has been determined as the most suitable upon receipt of the preamble symbols.