Performance analysis of borrowing with directional carrier locking strategy in cellular radio systems

Borrowing with directional carrier locking (BDCL) strategy is a carrier borrowing based DCA for FDMA/TDMA cellular systems. When a call arrives at a cell and finds all voice channels busy, a carrier which consists of multiple voice channels can be borrowed from its neighboring cells if such borrowing does not violate the cochannel interference constraint. Analytical models for the BDCL strategy are proposed. Those models are the extensions of previous studies in which single voice channel per carrier were considered. Two approaches are used: cell group decoupling analysis and phantom cell analysis. In cell group decoupling analysis, a cell is decoupled together with its neighbors from the rest of the network for finding its blocking probability. Phantom cell analysis is an approximate analysis that can handle realistic planar cellular systems with a three cell channel reuse pattern. To find the blocking probability of a cell, two phantom cells are used to represent its six neighboring cells. For low to medium traffic loads and small number of voice channels per carrier, we show that both analytical models provide accurate prediction of the system blocking probability