Joint User Association and Power Control for Load Balancing in Downlink Heterogeneous Cellular Networks

Abstract

Instead of achievable rate in the conventional association, we utilize the effective rate to design two association schemes for load balancing in heterogeneous cellular networks (HCNs), which are both formulated as such problems with maximizing the sum of effective rates. In these two schemes, the one just considers user association, but the other introduces power control to mitigate interference and reduce energy consumption while performing user association. Since the effective rate is closely related to the load of some BS and the achievable rate of some user, it can be used as a key factor of association schemes for load balancing in HCNs. To solve the association problem without power control, we design a one-layer iterative algorithm, which converts the sum-of-ratio form of original optimization problem into a parameterized polynomial form. By combining this algorithm with power control algorithm, we propose a two-layer iterative algorithm for the association problem with power control. Specially, the outer layer performs user association using the algorithm of problem without power control, and the inner layer updates the transmit power of each BS using a power update function (PUF). At last, we give some convergence and complexity analyses for the proposed algorithms. As shown in simulation results, the proposed schemes have superior performance than the conventional association, and the scheme with joint user association and power control achieves a higher load balancing gain and energy efficiency than conventional scheme and other offloading scheme.

Leveraging mobility and content caching for proactive load balancing in heterogeneous cellular networks

“…For each user u ∈ U, its probability transition matrix P u and sojourn time distribution matrix Θ u are estimated using Equations (10) and (11), respectively. Selected top six cells of the user10 are 516, 517, 521, 522, 528, and 599.…”

“…Various load balancing (LB) solutions have been proposed (eg, see other works) to address the uneven load issue; however, they operate in reactive mode. Under the vast deployment of nodes such as HetNets, these reactive LB policies may become a bottleneck that hinders network to deliver contents seamlessly and leads to worse user experience.…”

“…Among the aforementioned challenges, imbalanced load distribution between macro and small cells is a long-standing problem in these HetNets, which results in inefficient utilization of systems' installed capacity and users' QoE degradation. 7,8 Various load balancing (LB) solutions have been proposed (eg, see other works [7][8][9][10][11][12][13] ) to address the uneven load issue; however, they operate in reactive mode. Under the vast deployment of nodes such as HetNets, these reactive LB policies may become a bottleneck that hinders network to deliver contents seamlessly and leads to worse user experience.…”

Joint backhaul bandwidth and power allocation in heterogeneous cellular networks: A two‐level approach

“…In HCNs, resource allocation, such as power and bandwidth allocation, is an efficient approach to optimize the network performance and guarantee quality of service (QoS) requirements of users. In the literature, resource allocation problem was studied from different viewpoints, such as optimizing the energy efficiency, and maximizing the network throughput or different kinds of utilities . As a new concept of resource, wireless slice allocation was addressed in Kong and Karagiannidis .…”

User Association and Small-Cell Base Station On/Off Strategies for Energy Efficiency of Ultradense Networks

“…Ge et al [15] proposed a joint user association and user scheduling algorithm for load balancing by exploiting a distributed convex optimization technique called the alternating direction method of multipliers. Zhou et al [16] maximized the weighted sum of long-term rates to balance the network load and thus achieved higher load balancing gain and energy efficiency. Shen and Yu [17] investigated pricingbased BS association schemes for heterogeneous networks and proposed a distributed price update strategy based on a coordinate descent algorithm in the dual domain.…”