QoS-Aware Load Balancing in 3GPP Long Term Evolution Multi-Cell Networks

Abstract

Abstract-In this paper, we investigate load balancing problem in 3GPP Long Term Evolution (LTE) network. Since LTE network aims to serve heterogeneous users with different Quality of Service (QoS) requirements, the influence of load imbalance is quite different. For those users with minimum rate requirements, it may result in high block probability, while for others without minimum rate requirements, the throughput of boundary users may be degraded. In this paper, we take all the differences into account and formulate the problem as a multi-objective optimization problem. Then we analyze its complexity, and propose our solution framework, which includes QoS-guaranteed hybrid scheduling, QoS-aware handover for users with and without QoS requirements, and call admission control. Extensive simulations are conducted and the results show that the proposed framework leads to significantly better load balancing, and thus the decrease in call block probability of users with QoS requirements, and the increase in throughput of boundary best effort users.Index Terms-3GPP LTE, load balancing, Quality of Service (QoS)

Ripple algorithm: An LTE load balance mechanism with distributed and heuristic approach

“…Some examples of threshold parameters are bandwidth of each base station [6], the variance of the amount of stations connected to a base station [7], the variance of all eNodeBs' bandwidth [5].…”

“…Many algorithms have been proposed [1], [4], [7]- [11]. An interesting technique is the cell breathing technique proposed by [12], [13].…”

On Femto placement and decoupled access for downlink and uplink in enterprise environments

“…Lot of existing literature discuss about the load balancing in LTE systems by varying the handover hysteresis margin, dynamic BS power control [15] and centralized load balance using software defined network (SDN) approaches. In [6,7,19] authors proposed a multiobjective problem with the objective of load balance by meeting QoS requirements and the network utility of other services like voice, video and online gaming, but the running time complexity of the proposed optimization problem is high. So, they proposed a practical algorithm which considers QoS guaranteed hybrid scheduling, handover of users with and without QoS requirements and call admission control.…”

“…The user U t uses Femto 2 for both uplink and downlink communication because the signal strength from Femto 2 is very high for the user U t . Suppose a Femto is fully loaded when compared to its neighboring Femtos, the traditional offloading or load balancing algorithms [6,7] will shift some of the UEs for both uplink and downlink from the loaded cell to one of less loaded cells (target cells) provided that these UEs still could get connected to the target cell. This type of offloading is a forced handover based on the load but not based on signal strength, because the signal strength when connected to the initial serving Femto will be high compared to the target Femto.…”

An improved throughput estimation method and dynamic user association in multi-cell networks

“…Several approaches have been identified in the literature to propose load-aware user association rules [1], [2], [3], [4]. The main idea is summarized simply as the follows: First, users calculate receivable throughput from all of the nearby BSs, as a potential candidate for connection.…”