Abstract
Heterogeneous wireless networks are a promising technology in next generation wireless communication networks, which has been shown to efficiently reduce the blind area of mobile communication and improve network coverage compared with the traditional wireless communication networks. In this paper, a robust power allocation problem for a two-tier heterogeneous wireless networks is formulated based on orthogonal frequency-division multiplexing technology. Under the consideration of imperfect channel state information (CSI), the robust sum-rate maximization problem is built while avoiding sever cross-tier interference to macrocell user and maintaining the minimum rate requirement of each femtocell user. To be practical, both of channel estimation errors from the femtocells to the macrocell and link uncertainties of each femtocell user are simultaneously considered in terms of outage probabilities of users. The optimization problem is analyzed under no CSI feedback with some cumulative distribution function and partial CSI with Gaussian distribution of channel estimation error. The robust optimization problem is converted into the convex optimization problem which is solved by using Lagrange dual theory and subgradient algorithm. Simulation results demonstrate the effectiveness of the proposed algorithm by the impact of channel uncertainties on the system performance.
Highlights
With the exponential growth of mobile data driven by various communication applications, such as WIFI and smartphones, the traditional wireless network via macrocell base stations (BSs) can not satisfy higher communication requirements
channel state information (CSI) feedback, the outage-based probability constraints are transformed into closed-from expressions by approximate methods
With the Lagrange dual method, the robust power allocation problem has been decomposed into a dual problem
Summary
With the exponential growth of mobile data driven by various communication applications, such as WIFI and smartphones, the traditional wireless network via macrocell base stations (BSs) can not satisfy higher communication requirements (e.g., throughput and coverage). Many femtocells with low-cost and low-energy consumption are distributed around macro BSs randomly femtocell users (FUs) share the same spectrum resource with macrocell users (MUs) to obtain better spectral efficiency (e.g., co-channel development) and supplement traditional single-tier cellular systems. Interference mitigation is very important for which power control-based resource allocation (i.e., power allocation) has been a feasible method for Heterogeneous wireless networks (HetNets) [4,5]. The main task in resource allocation of underlay femtocell networks is to reduce the interference power received at MUs and simultaneously obtain the expected performance
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