Frequency sharing for reuse partitioning and underlay system in sectorized wireless networks

In a typical mobile network, a group of channel sets identical the number of sectors in a cell is allocated to each cell type and reused symmetrically. Thus, deploying an underlay system requires costly modifications. A frequency allocation scheme called channel alternation and rotation for tiered wireless networks (CART) is proposed to exploit the scarce radio spectrum and current infrastructure build-outs. In CART, each cell type is allocated an extra channel set for rotating and alternating frequency channels among co-channel cells and between the two systems to enhance frequency reuse efficiency. In a typical environment requiring a carrier-to-interference ratio (C/I) about 17 dB, for example, CART increases offered traffic by 69 percent over a traditional two-tiered system. CART is simple and can also be easily modified for other wireless networks. Since infrastructure modification is not required, it incurs no additional costs.