Patent ID: 8718157

Claim:
A wireless communications network comprising: first and second wireless transceiving stations, the first station comprising: first storage means storing a first codebook comprising a plurality of entries, each entry being a representation of a precoding for a transmission by that first station, and second storage means storing a second codebook; the second station comprising: a channel state measurement means for measuring state of a channel over which a wireless communication is borne from the first and second stations, third codebook storage means storing a third codebook comprising a plurality of entries, each entry of the third codebook comprising data representative of possible precodings, the entries of the third codebook corresponding to the entries of the first codebook, precoding selection means operable to select an entry from said third codebook; fourth codebook means storing a fourth codebook corresponding with the second codebook of the first station, wherein each entry in said fourth codebook is usable to specify a particular precoding from the possible precoding represented by an entry selected from the third codebook; a selecting device configured to select an entry in said fourth codebook by predicting the channel quality obtained when different entries in the fourth codebook are used to specify a precoding; and channel state indicator feedback means for transmitting from said second station to said first station a first indicator corresponding to the entry selected from the third codebook and a second indicator corresponding to the entry selected from the fourth codebook, to enable said first station to select a precoding on the basis of said indicators; wherein the second indicator enables said first station to select, from said second codebook, data representing criteria for a precoding to meet, such that the first station can construct a precoding within the criteria defined by the data from the second codebook with regard to the indicator corresponding to the entry in the first codebook.