Optimal Scheduling across Heterogeneous Air Interfaces of LTE/WiFi Aggregation

TL;DR

This paper proposes an optimized scheduling method for LTE/WiFi aggregation that minimizes licensed spectrum use while maintaining QoS, using a novel semi-Markov model and efficient convex optimization techniques.

Contribution

It introduces a new semi-Markov model for aggregated capacity and an iterative convex optimization algorithm for resource allocation in LWA.

Findings

Significant reduction in licensed spectrum usage.

Effective QoS maintenance across heterogeneous bands.

Superior performance over heuristic methods.

Abstract

LTE/WiFi Aggregation (LWA) provides a promising approach to relieve data traffic congestion in licensed bands by leveraging unlicensed bands. Critical challenges arise from provisioning quality-of-service (QoS) through heterogenous interfaces of licensed and unlicensed bands. In this paper, we minimize the required licensed spectrum without degrading the QoS in the presence of multiple users. Specifically, the aggregated effective capacity of LWA is firstly derived by developing a new semi-Markov model. Multi-band resource allocation with the QoS guarantee between the licensed and unlicensed bands is formulated to minimize the licensed bandwidth, convexified by exploiting Block Coordinate Descent (BCD) and difference of two convex functions (DC) programming, and solved efficiently with a new iterative algorithm. Simulation results demonstrate significant performance gain of the proposed approach over heuristic alternatives.