The term ‘HetNet’ (heterogeneous network) has been so overused and vaguely defined, for so long, that it is easy to forget that this is a real, and difficult, approach to building a mobile network – and one that is finally becoming essential rather than theoretical. This is what Small Cell Forum defines as a “multi-x environment – multi-technology, multi-domain, multi-spectrum, multi-operator and multi-vendor”. That sums up a true HetNet very well, and this will increasingly be the only way that operators can meet the rising demands for mobile data capacity, while keeping their capex and opex costs under control and their quality of service acceptable. In Rethink’s latest research report and forecast, ‘HetNet Deployments and Trends 2014-2021 – Multilayer and…