Designing Optimal Heterogeneous Networks

Wireless operators worldwide are struggling with network congestion following explosion of mobile data traffic over the last several years. In many countries, spectrum addition is not an option. Improvement in spectral efficiency is not keeping up with traffic growth. Thus the only option to add network capacity is to re-use existing spectrum. However, in many large cities, inter-site distances among macro cells are reaching the lower bounds of practical deployment. Thus the industry is exploring alternative network architectures. Heterogeneous Networks (HetNets) are defined as a mix of multi-technology macro and Small Cells. The Small Cells may be using licensed and/or unlicensed spectrum bands. The challenges of deploying Small Cells are three fold: (1)Where to deploy them so that maximum traffic is captured, (2)How to minimize interference with macro cells and (3)How to minimize deployment costs. This paper discusses the methodology for balancing the three constraints in a real-life network.