Joint Power Control, Channel Assignment and Cell Association in Heterogeneous Cellular Networks

TL;DR

This paper proposes a novel iterative scheme for joint power control and channel assignment in HetNets, significantly improving uplink sum rate and reducing interference compared to traditional methods.

Contribution

It introduces a convergent joint optimization scheme for power control and channel assignment in two-tier HetNets, enhancing user rates and reducing interference.

Findings

Almost 50% of users achieve rates above 6 bps/Hz.

Fractional frequency reuse increases average rates by up to 20%.

Scheme outperforms SINR-based schemes in user rate distribution.

Abstract

Heterogeneous network (HetNet) is a promising concept for increasing capacity and alleviating spectrum scarcity. In HetNets, however, channel assignment and transmit power control affect the distribution of users among base stations. We present a novel scheme to maximize the uplink sum rate in two-tier HetNets with one macrocell and several femtocells, where the transmit power of each user is bounded and at least one channel is assigned to each user. We divide the problem into two sub-problems: one for channel assignment and one for transmit power control and solve them by iteratively alternating between the two. Our scheme is convergent and yields a transmission rate above 6 bps/Hz for almost 50% of users as compared to the same for 10% of users in SINR-based schemes. When users are in cell boundaries, the average transmission rate for fractional frequency reuse is up to 20% more compared to the conventional full frequency reuse. This is due to reduced transmit power resulting in less interference.