Backhaul-Aware User Association in FiWi Enhanced LTE-A Heterogeneous Networks

Abstract

In this paper, we shed some light on the latency and reliability issues of mobile backhaul networks, which have been largely ignored in the past, and examine their impact on LTE-A heterogeneous networks (HetNets). Specifically, we propose a backhaul-aware user association algorithm for fiberwireless (FiWi) enhanced LTE-A HetNets. The performance limiting factors of state-of-the-art fiber backhaul infrastructures are highlighted and a variety of solutions are described. In order to mitigate the vulnerability of the backhaul against fiber cuts, we introduce different advanced protection techniques. Accounting for the given conditions of the backhaul in terms of delay and reliability, we present a distributed load-balancing algorithm for user association in FiWi-LTE HetNets. The proposed algorithm is analyzed and evaluated numerically by comparing its performance with state-of-the-art alternative approaches in terms of average delay, blocking probability, average achievable throughput, and service interruption percentage. The obtained results demonstrate that our algorithm outperform its counterparts in terms of delay and service interruption percentage, while its average achievable throughput is the same as that of a backhaul-unaware alternative solution. In addition, the blocking probability of the proposed backhaul-aware load-balancing method is shown to be higher than that of backhaul-unaware ones.

Network utility optimization-based joint user association and content placement in heterogeneous networks

“…In the past few years, user association or cell selection have been studied for HetNets [2][3][4][5][6][7]. In [2], the authors address the user association problem in the downlink transmissions of a multi-tier HetNet and propose a unified distributed algorithm, which aims at maximizing the sum utility of long-term rate and minimizing global outage probability at the same time.…”

“…In [2], the authors address the user association problem in the downlink transmissions of a multi-tier HetNet and propose a unified distributed algorithm, which aims at maximizing the sum utility of long-term rate and minimizing global outage probability at the same time. In [3], the authors examine the latency and reliability issues of fiber-wireless (FiWi)-enhanced LTE-A HetNets and propose a backhaul-aware user association algorithm to achieve inter-cell load balancing and network performance improvement. The authors in [4] investigate the user association and resource allocation problem in HetNets and propose an optimal user association and resource allocation algorithm which minimizes the average packet delay of user traffic across the network.…”

“…Different user association or cell selection strategies may result in different network transmission performance and quality of service (QoS) to users due to the heterogeneity of RANs. While various user association schemes have been proposed for HetNets [2][3][4][5][6][7] and effectively enhanced the transmission performance of the RANs, the backhaul links may still cause challenges and difficulties in offering QoS guaranteed services to UEs. In particular, the demanding requirements of user services, such as multimedia streaming, web browsing applications, and socially interconnected networks, may cause network congestion and long transmission delay in backhaul links [8].…”

“…• The problem of user association or content placement in HetNets has been studied separately in previous works [2][3][4][5][6][7] and [11][12][13][14][15][16]. In this paper, we jointly consider the user association and content placement problem in cache-enabled HetNets and design jointly optimal strategies so that the overall performance of the networks can be maximized.…”

Fuzzy Q-learning-based user-centric backhaul-aware user cell association scheme

“…The idea of decoupled downlink/uplink UA for load balancing under backhaul capacity and cell load constraints is advocated in [14]. Similarly, load balancing with regard to backhaul latency and reliability limitations is studied in [15]. Authors in [16] propose a UA strategy that conserves the overall network energy, at the cost of the reduction in users' throughput, by minimizing both the number of active cells and backhaul switches.…”