Load Balancing via Joint Transmission in Heterogeneous LTE: Modeling and Computation

TL;DR

This paper models and optimizes load balancing in LTE HetNets using Joint Transmission, proposing an algorithm that significantly reduces maximum cell load compared to traditional methods.

Contribution

It extends load coupling models to include JT, analyzes optimality in two-cell scenarios, and introduces JT-MinMax for effective load balancing in HetNets.

Findings

JT-MinMax reduces maximum cell load significantly.

Optimality in two-cell case achieved in linear time.

Numerical results show performance gains over non-JT methods.

Abstract

As one of the Coordinated Multipoint (CoMP) techniques, Joint Transmission (JT) can improve the overall system performance. In this paper, from the load balancing perspective, we study how the maximum load can be reduced by optimizing JT pattern that characterizes the association between cells and User Equipments (UEs). To give a model of the interference caused by cells with different time-frequency resource usage, we extend a load coupling model, by taking into account JT. In this model, the mutual interference depends on the load of cells coupled in a non-linear system with each other. Under this model, we study a two-cell case and proved that the optimality is achieved in linear time in the number of UEs. After showing the complexity of load balancing in the general network scenario, an iterative algorithm for minimizing the maximum load, named JT-MinMax, is proposed. We evaluate JT-MinMax in a Heterogeneous Network (HetNet), though it is not limited to this type of scenarios. Numerical results demonstrate the significant performance improvement of JT-MinMax on min-max cell load, compared to the conventional non-JT solution where each UE is served by the cell with best received transmit signal.