Distributed Pricing-Based User Association for Downlink Heterogeneous Cellular Networks

Abstract

Abstract-This paper considers the optimization of the user and base-station (BS) association in a wireless downlink heterogeneous cellular network under the proportional fairness criterion. We first consider the case where each BS has a single antenna and transmits at fixed power, and propose a distributed price update strategy for a pricing-based user association scheme, in which the users are assigned to the BS based on the value of a utility function minus a price. The proposed price update algorithm is based on a coordinate descent method for solving the dual of the network utility maximization problem, and it has a rigorous performance guarantee. The main advantage of the proposed algorithm as compared to the existing subgradient method for price update is that the proposed algorithm is independent of parameter choices and can be implemented asynchronously. Further, this paper considers the joint user association and BS power control problem, and proposes an iterative dual coordinate descent and the power optimization algorithm that significantly outperforms existing approaches. Finally, this paper considers the joint user association and BS beamforming problem for the case where the BSs are equipped with multiple antennas and spatially multiplex multiple users. We incorporate dual coordinate descent with the weighted minimum mean-squared error (WMMSE) algorithm, and show that it achieves nearly the same performance as a computationally more complex benchmark algorithm (which applies the WMMSE algorithm on the entire network for BS association), while avoiding excessive BS handover.

IoT’s Tiny Steps towards 5G: Telco’s Perspective

“…Multi-RAT is defined as the capability of a mobile network to support multiple radio access technology with seamless interworking among them [229]. When deployed in heterogeneous networks (HetNets), with traffic offloading among different RATs, multi-RAT improves capacity [230], supports better communication rates [34,[117][118][119]231,232], better energy efficiency [34,[117][118][119]231,232], and ensures seamless connectivity with higher QoS [230]. In designing a heterogeneous RAT, researches are finding solutions for cell-association and traffic-offloading algorithms [217].…”

Enabling 5G mobile wireless technologies

“…This heterogeneous network architecture also enables efficient traffic offloading among different network tiers and RATs to better support the growing mobile traffic with enhanced QoS, communication rates, and energy efficiency [51][52][53][54][55][56]. In fact, research on multi-tier HetNets where communications among different network tiers (e.g., macro, micro and small-cell tiers) share the same microwave spectrum has been one of the most active research topics over the past years [57].…”

“…Other important research issues for multi-tier HetNets include mobility management and load balancing via dynamic BS association and admission control [51][52][53][54][55][56]. To effectively manage cross-tier interference and perform load balancing in the dense HetNet, distributed solutions using the self-optimization network (SON) techniques are desirable, which typically require reliable and low-delay backhauls for a large number of small cells (i.e., pico and femto cells).…”

QoS-aware User Load Management with Beamforming for Energy Efficiency in Wireless Networks

“…The transport layer based congestion control is tackled by transferring users from loaded cells to less congested cells to avoid the link bottleneck for LTE systems in [3]. Additionally, in [4], [5] a joint optimization of beamforming to maximum and association control was investigated to balance the network load across multiple cells by updating beamforming weight vectors to optimize the selection criteria of serving BTs and beamforming policy. In general, channel variation status can be upgraded into beamforming weight vectors within the cell, but the benefit of the proposed work is to exchange the user association between the cells.…”