Load balancing mechanisms for indoor temporarily overloaded heterogeneous femtocell networks

Abstract

Macrocell and small cell deployments and self-organizing network (SON) techniques work together to increase indoor cellular network capacity and ensure better quality of service (QoS). As a consequence of uneven local user densities and temporal or spatial fluctuations of traffic, the network may suffer overload situations, which partially degrades network performance. Load balancing self-optimization introduces automatic and intelligent mechanisms to tune network parameters in order to improve the overall cellular network performance. This paper proposes novel load balancing methods based on fuzzy logic controllers (FLC) that evaluate temporarily overloaded situations and resize cell coverage areas by an adaptive process of adjusting cell transmission power. To accomplish this goal, classical network indicators are analyzed (e.g., call blocking ratio, available radio resources) while a novel and simple, although powerful, indicator (not mentioned in the literature yet) is additionally proposed as the system input. This indicator is related to the maximum allowed number of users in a femtocell. The proposed methods have been evaluated and compared with the literature in a realistic scenario.

Coordinated location-based self-optimization for indoor femtocell networks

“…The Power Load and User Sharing (PLUS) optimization mechanism presented in [14] has been selected as the state-of-the-art reference method to compare the proposed algorithms. PLUS is aimed at traffic steering at indoor scenarios.…”

“…Moreover, they did not address temporary overloaded situation or context aware information, but permanent long-term situations and network KPIs. The authors in [14] studied the importance of analyzing the available radio resources as well as the maximum capability of users' connections for mobility load balancing in temporal overloaded situations. Nevertheless, that work did not consider the context aware information which could improve the algorithm performance.…”

“…In case that target is positive, the transmission power variation PTx target applied to that target cell is calculated as follows in Eq. (14) , where PTx target is equal to target 2 the first iteration because initial values of PTx target are set to zero. Otherwise, target is negative, this step is skipped.…”

Improving load balancing techniques by location awareness at indoor femtocell networks

“…Nevertheless, temporarily overloaded cells issues were not addressed in that work. The study of [20] analyzed the importance of the femtocell capacity in terms of the number of active users for mobility load balancing in temporal overloaded situations. However, the user location was not considered in that study.…”

Technical advances in the design and deployment of future heterogeneous networks

“…The paper "Load balancing mechanisms for indoor temporarily overloaded heterogeneous networks" by Aguilar-Garcia et al [5] investigates the problem of temporal or spatial fluctuations of traffic in heterogeneous networks that may result to overload situations. It proposes novel load balancing methods based on fuzzy logic controllers (FLC) which evaluate temporarily overloaded situations and resize cell coverage areas by an adaptive process of adjusting cell transmission power.…”