Location-Aware Cross-Tier Coordinated Multipoint Transmission in Two-Tier Cellular Networks

TL;DR

This paper introduces a location-aware cross-tier cooperation scheme in two-tier cellular networks that improves performance for interference-affected users while reducing backhaul load, using stochastic geometry for analysis.

Contribution

It proposes a novel location-aware CoMP scheme that selectively cooperates based on user interference conditions, reducing backhaul usage compared to traditional methods.

Findings

Significant reduction in outage probability for high interference users.

Improved achievable data rates for users in interference-prone areas.

Lower load per base station due to selective cooperation.

Abstract

Multi-tier cellular networks are considered as an effective solution to enhance the coverage and data rate offered by cellular systems. In a multi-tier network, high power base stations (BSs) such as macro BSs are overlaid by lower power small cells such as femtocells and/or picocells. However, co-channel deployment of multiple tiers of BSs gives rise to the problem of cross-tier interference that significantly impacts the performance of wireless networks. Multicell cooperation techniques, such as coordinated multipoint (CoMP) transmission, have been proposed as a promising solution to mitigate the impact of the cross-tier interference in multi-tier networks. In this paper, we propose a novel scheme for Location-Aware Cross-Tier Cooperation (LA-CTC) between BSs in different tiers for downlink CoMP transmission in two-tier cellular networks. On one hand, the proposed scheme only uses CoMP transmission to enhance the performance of the users who suffer from high cross-tier interference due to the co-channel deployment of small cells such as picocells. On the other hand, users with good signal-to-interference-plus-noise ratio (${\rm SINR}$) conditions are served directly by a single BS from any of the two tiers. Thus, the data exchange between the cooperating BSs over the backhaul network can be reduced when compared to the traditional CoMP transmission scheme. We use tools from stochastic geometry to quantify the performance gains obtained by using the proposed scheme in terms of outage probability, achievable data rate, and load per BS. We compare the performance of the proposed scheme with that of other schemes in the literature such as the schemes which use cooperation to serve all users and schemes that use range expansion to offload users to the small cell tier.