Method and apparatus for improving sector to sector isolation in a Fourier transform matrix system

A wireless communication system that provides sector-to-sector isolation when transmitting data between a plurality of Fourier transform matrices, the system comprising:

• first and second Fourier transform matrices;
• plurality of transmit paths between the first and second Fourier transform matrices;
• a signal generator that places a signal into each of the plurality of transmit paths;
• a first phase adjuster interposing the signal generator and each transmit path for providing an appropriate phase adjustment of the generated signal into each transmit path;
• an amplitude modulation (AM) detector that measures an output associated with the second Fourier transform matrix (FTM) due to the input into the transmit paths from the signal generator;
• a correlator that correlates output from the AM detector and the signal generated by the signal generator;
• a second phase shifter interposing the first phase adjuster and each transmit path, the phase shifter provides a phase adjustment of the transmit path phase for establishing a sector-to-sector isolation that is greater than a predetermined amount based upon control signals from the correlator;
• and
• an attenuator on each of the transmit paths, each attenuator provides attenuation for its transmit path in order to determine an appropriate amplification needed for each transmit path for establishing a sector-to-sector isolation that is greater than a predetermined amount, each attenuator receives control signals from the correlator.

A method for providing increased sector-to-sector isolation when transmitting data between a plurality of Fourier transform matrices, each having an input Fourier transform matrix (FTM), an output FTM, and a plurality of transmit paths therebetween, the method comprising:

• applying a tone to one of the plurality of transmit paths so that a correlated output can be produced;
• measuring an output of the output FTM;
• correlating the output of the output FTM against the tone applied to produce a correlated output;
• adjusting a phase of the transmit path such that a direct current value of the correlated output is compensated for errors;
• and
• adjusting an attenuation of the transmit path such that the direct current of the correlated output is compensated for errors.