Optimum sectorization for CDMA 1900 base stations

Since minimizing the co-channel interference in the conventional cellular technologies (AMPS, TDMA, and GSM) leads to better spectral efficiency, these technologies require a systematic frequency planning scheme. Generally, cells are grouped in a cluster of 7 (N=7). Each cluster reuses the same frequency to maximize bandwidth efficiency. To further minimize the co-channel interference from adjacent clusters, sector antennas are used. A cell is typically sectorized into three sectors (K=3) to achieve rapid frequency reuse. The deployment practices include using the N=7, K=3 or using the N=4, K=6 frequency reuse scheme. Because of the flexibility of the CDMA technology, restrictions of using the conventional clusterization and/or sectorization schemes may not be warranted. In fact, to maximize the utilization of existing resources such as cell-site equipment, structures, real-estate, backhauls, etc., employing a non-standard sectorization scheme will yield a more optimum configuration and a more cost-effective solution. We address such non-standard sectorizations.