A High-Capacity Cellular Network by Improved Sectorization and Interleaved Channel Assignment

Abstract

In this paper, we propose an improved sectorization scheme, called Narrow Beam Quad-sector Cell (NBQC), in which each cell is divided into 4 sectors and each sector is covered by a 60° antenna. The NBQC structure allows to implement the concept of interleaved channel assignment (ICA), which can take full advantage of antenna directivity. With ICA, the NBQC system can enhance the system performance from several perspectives. First, the NBQC system with the ICA significantly improves the system capacity and quality of radio links. We demonstrate that in a typical radio environment, the NBQC system can achieve a reuse factor N = 2 with the signal-to-interference ratio (SIR) as high as 11 dB in 90 percent of the cell area. Comparing to the Global System for Mobile telecommunications (GSM) that requires N = 4 to achieve the SIR requirement of 9 dB, our proposed system thus improves the system capacity by a factor of two. Second, the proposed NBQC system can also improves the coverage performance. Third, the proposed system has better handoff performance because it is less sensitive to the impact of handoff hysteresis.