Frequency reuse scheme with reduced co-channel interference for fixed cellular systems

A new frequency reuse scheme which reduces co-channel interference in comparison with the conventional scheme is presented for use in fixed cellular or wireless local loop systems where the antennas of subscriber units are fixed and directional. The new scheme is evaluated in a three-sector cell plan employing frequency reuse numbers N=4 and N=7 as a function of the subscriber unit antenna directivity. It is shown that a substantial improvement is obtained with the new scheme compared to the conventional scheme if the subscriber unit antenna beam width is narrower than ~150 degrees. For the case of a 60 degree antenna beam width, for example. The improvement is >7 dB in the signal to co-channel interference ratio averaged along the cell boundary for both N=4 and N=7 cases