Impact of co-channel small cell deployments on uplink capacity of W-CDMA cellular networks

The operation of wireless cellular networks can be efficiently supported by secondary small cells that are deployed on-demand in traffic hotspots within the coverage area of primary network cells. In view of the growing traffic demand and the limited spectrum available, the objective of this study is to examine the conditions under which the secondary base stations can share the same communication channel with the primary base stations under the constraint of a predefined quality of service, typical for uplink communications. In particular, considering a minimum required signal-to-interference-and-noise ratio (SINR) for each uplink transmission accommodated in a common interference-limited channel, we formally assess the impact of the secondary infrastructure on the global achievability of the target SINRs via distributed closed-loop power control. Both the effects of intra-cell load and inter-cell coupling are investigated with the aim of providing deployment guidelines for the secondary small-cell infrastructure. Analytical conclusions are validated numerically by 3GPP-compliant simulations of a network deployed in Dublin.