Method for operating a radio station in a cellular communication network

A method for operating a plurality primary stations (200, 500) each comprising a transceiver for communicating with at least one secondary station (210, 510), said transceiver including at least two antennas (204a, 204b, 504a, 504b), the method comprising a first one of the plurality of the primary stations transmitting to a secondary station (210, 510) for a single spatial channel (211, 511) a first set of reference symbols with a first precoding vector applied before transmission and a second one of the plurality of the primary stations transmitting to secondary station at least one second set of reference symbols with a corresponding second precoding vector applied before transmission, the at least one second set of reference symbols being orthogonal to the first set of reference symbols.

A method for operating a secondary station (201, 501), the secondary station comprising a transceiver for communicating with at least one primary station (200, 500), the method comprising the secondary station receiving from the primary station for a single spatial channel (211, 511) a first set of reference symbols and at least one second set of reference symbols, the at least one second set of reference symbols being orthogonal to the first set of reference symbols, and the secondary station computing a phase difference between the phase of the received first set of reference symbols and the phase of at least one of the received at least one second set of reference symbols.

A primary station (200, 500) comprising a transceiver for communicating with a plurality of secondary stations, said transceiver including at least two antennas (204a, 204b, 504a, 504b), the transceiver being adapted for transmitting to a secondary station (210, 510) for a single spatial channel (211, 511) a first set of reference symbols with a first precoding vector applied before transmission and at least one second set of reference symbols with a corresponding second precoding vector applied before transmission, the at least one second set of reference symbols being orthogonal to the first set of reference symbols.

A secondary station (210, 510) comprising a transceiver for communicating with at least one primary station (200, 500), the transceiver being adapted for receiving from the primary station for a single spatial channel (211, 511) a first set of reference symbols and at least one second set of reference symbols, the at least one second set of reference symbols being orthogonal to the first set of reference symbols, and the secondary station comprising control means for computing a phase difference between the phase of the received first set of reference symbols and the phase of at least one of the received at least one second set of reference symbols.