Evaluation of channel assignment strategies for TIA IS-54 system

An interference limited environment is proposed for the evaluation of channel assignment strategies for digital systems based in the IS-54 standard. This environment consists of two rings of co-channel interference cells (133 cells) with uniform and nonuniform traffic distribution. At call initiation the C/I ratio is evaluated. A minimum C/I value in dB is required for attending a call, otherwise, the call is rejected. The propagation model takes into account log normal shadowing losses. The nonuniform traffic distribution is the real traffic distribution in the system of one of the two cellular companies of Mexico City. Results are presented for fixed channel assignment (FCA), borrowing with channel ordering (BCO), borrowing with directional channel-locking (BDCL) and the compact pattern based dynamic channel assignment (CP) strategy. In order to evaluate these strategies in the new digital cellular system, some modifications and combinations with different time slot assignment techniques were used. In the proposed interference limited environment the borrowing with directional channel-locking strategy gave better results with both uniform and nonuniform traffic distribution cases when the AMPS standard was used. However, borrowing with channel ordering outperforms all the other strategies when the IS-54 standard was used.