Matérn-like model based analysis for power control in user-centric 5G networks

User-centric network (UCN) forms a dynamic femto access point group (FAPG) for each user equipment (UE) to provide consistent user experience in 5G. However, femto access point (FAP) conflict problem occurs in UCN when the same FAP is included in different UEs' FAPGs. This paper proposes a power control strategy in UCN using Matérn-like model to avoid FAP conflict, and derives semi-closed form expression of coverage probability leveraging tools from stochastic geometry. In this user-centric power control strategy, each UE determines its FAPG radius considering the UE's distance to the nearest FAP, and FAPs within UE's FAPG decrease transmission power by a power control factor to mitigate strong interference for the UE. Furthermore, whether a FAP performs power reduction is determined using Matérn-like model, where two FAPs in the same FAPG do not transmit at full power simultaneously in order to avoid severe interference, thus resolving FAP conflict. The analysis shows that, there exist certain values of FAP-to-UE density ratio and FAPG radius where further increasing them would only bring about very small gain in coverage probability. When FAP-to-UE density ratio equals 1 and FAPG radius coefficient equals 1.5, the coverage probability of user-centric power control strategy is improved by about 49% compared with the non-coordination baseline.