Channel borrowing schemes in sectored cellular systems with worst case SIR analysis

We investigate where a channel can be selected for borrowing in a sectored cellular system with a 3-cell reuse pattern. After classifying the channel borrowing schemes as intra-cell borrowing (intra-CBS) and inter-cell borrowing (inter-CBS), the tradeoff between the received signal quality and the channel locking in sectors is studied for both schemes. It is shown that intra-CBS with 2 sector-locking and inter-CBS with no locking provides comparable SIR performance for the downlink. For the uplink, the worst case SIR using inter-CBS is still found to be 15 dB with no locking requirement. Therefore, the inter-cell borrowing scheme is expected to increase the system capacity at the expense of little quality degradation.