Space multiplex radio communication method and radio communication apparatus

A radio communication apparatus comprising:

• N independent transmitters, said N being an integer equal to or greater than 2;
• a transmitting side training sequence generator for generating a known training sequence;
• a switch for providing said training sequence to said N independent transmitters, sequentially;
• a transmitting antenna provided with N elements which are supplied with N transmitter outputs, respectively;
• a receiving antenna provided with N elements for producing N received signals;
• an N-input-N-output inter-channel interference canceller, supplied with the N received signals from said N elements of said receiving antenna, for dividing each of said N received signals to N divided signals of N×N paths, for weighting said N divided signals of said N×N paths, and for combining said weighted N signals for every N channels to generate N-channel combined signals;
• and
• a select switch for providing a received known training sequence sequentially from the N elements of said receiving antenna to corresponding one of the N inputs of said inter-channel interference canceller, respectively;
• wherein said inter-channel interference canceller comprises:
• N power dividers each for dividing one of the N received signals to N divided signals corresponding to the N channels, thereby producing divided signals of N×N paths;
• weighting factor multipliers for weighting said divided signals of said N×N paths by weighting factors, respectively, to generate weighted signals of N×N paths;
• N power combiners for combining said weighted signals of said N×N paths for every N corresponding to said N channels to obtain N-channel combined signals as signals corresponding to said N-channel transmitted signals;
• a receiving side training sequence generator for generating the known training sequence;
• a correlation detector for detecting correlation between each of weighted training sequences provided thereto as the weighted signals and the known training sequence generated by said receiving side training sequence generator to obtain a correlation matrix of N×N elements;
• and
• a controller for determining the weighting factors of said N×N paths so that the elements other than diagonal elements of said correlation matrix approach zero whereby the cross correlation coefficient between said N-channel combined signals is minimized.

A method for receiving N-channel space multiplex signals transmitted from N elements of a transmitting antenna, said method comprising the steps of:

• (a) receiving N-channel transmitted signals by N elements of a receiving antenna to generate N received signals;
• (b) dividing each of said N received signals into N divided signals corresponding to the N channels to obtain signals of N×N paths;
• (c) multiplying said signals of said N×N paths by weighting factors, respectively, to produce weighted signals of N×N paths;
• and
• (d) combining said weighted signals for every N channels to obtain N-channel combined signals;
• wherein said step (a) includes a step of setting all of the weighting factors to given values and a step of receiving, for each of transmissions of a known training sequence sequentially from N elements of a transmitting antenna, the known training sequence by successive selection of one of said N elements of said receiving antenna corresponding to one of the N channels to produce N received training sequences as said N received signals;
• said step (b) includes a step of dividing each of said N received training sequence into N divided training sequences corresponding to the N channels;
• said step (c) includes a step of multiplying the N divided training sequences by said N weighing factors, respectively, to produce N weighted training sequences for each of the N received training sequences;
• and
• said step (d) includes a step of obtaining correlation between each of the weighted training sequences and the known training sequence generated at the receiving side to thereby produce a correlation matrix of N×N elements, and a step of converging the weighting factors by an adaptive algorithm so that elements other than diagonal elements of said correlation matrix approach zero to thereby minimize cross correlation between said N received signals.

An apparatus for receiving N-channel transmitted signals from N elements of a transmitting antenna, said apparatus comprising:

• a receiving antenna provided with N elements for producing N received signals, said N being an integer equal to or greater than 2;
• an N-input-N-output inter-channel interference canceller supplied with said N received signals from said N elements of said receiving antenna, for dividing each of said N received signals to N divided signals of N×N paths, for weighting said N divided signals of said N×N paths, for combining said weighted N signals for every N channels to generate N-channel combined signals;
• a select switch for providing a received known training sequence sequentially from the N elements of said receiving antenna to corresponding one of the N inputs of said inter-channel interference canceller, respectively;
• wherein said inter-channel interference canceller comprises:
• N power dividers each for dividing one of the N received signals to N divided signals corresponding to the N channels, thereby producing divided signals of N×N paths;
• weighting factor multipliers for weighting said divided signals of said N×N paths by weighting factors, respectively, to generate weighted signals of N×N paths;
• N power combiners for combining said weighted signals of said N×N paths for every N corresponding to said N channels to obtain N-channel combined signals as signals corresponding to said N-channel transmitted signals;
• a receiving side training sequence generator for generating the known training sequence;
• a correlation detector for detecting correlation between each of weighted training sequences provided thereto as the weighted signals and the known training sequence generated by said receiving side training sequence generator to obtain a correlation matrix of N×N elements;
• and
• a controller for determining the weighting factors of said N×N paths so that the elements other than diagonal elements of said correlation matrix approach zero whereby the cross correlation coefficient between said N-channel combined signals is minimized.