# Virtual Cell Clustering with Optimal Resource Allocation to Maximize Cellular System Capacity

## TL;DR

This paper introduces a novel framework for cellular network optimization using virtual cell clustering and resource allocation schemes, achieving near-centralized performance with distributed methods.

## Contribution

It proposes a hierarchical clustering method for forming virtual cells and two new schemes for joint channel and power allocation in interference coordination.

## Key findings

- Distributed optimization approaches can achieve near-centralized performance.
- Virtual cell clustering reduces the performance gap between distributed and centralized optimization.
- The penalty of distributed optimization can be as high as 50% but can be minimized with proper design.

## Abstract

This work presents a new network optimization framework for cellular networks using neighborhood-based optimization. Under this optimization framework resources are allocated within virtual cells encompassing several base-stations and the users within their coverage areas. We form the virtual cells using hierarchical clustering with a minimax linkage criterion given a particular number of such cells. Once the virtual cells are formed, we consider an interference coordination model in which base-stations in a virtual cell jointly allocate the channels and power to users within the virtual cell. We propose two new schemes for solving this mixed integer NP-hard resource allocation problem. The first scheme transforms the problem into a continuous variables problem; the second scheme proposes a new channel allocation method and then alternately solves the channel allocation problem using this new method, and the power allocation problem. We evaluate the average system sum rate of these schemes for a variable number of virtual cells. These results quantify the sum-rate along a continuum of fully-centralized versus fully-distributed optimization for different clustering and resource allocation strategies. These results indicate that the penalty of fully-distributed optimization versus fully-centralized (cloud RAN) can be as high as 50%. However, if designed properly, a few base stations within a virtual cell using neighborhood-based optimization have almost the same performance as fully-centralized optimization.