Whilst there are multiple ways to grow network capacity, it is clear that small cells are needed in order to meet the challenge presented by the explosive growth in data traffic. Operators need to invest wisely and find ways to support the exponential traffic growth whilst driving down the cost per bit. Heterogeneous networks provide the opportunity to enjoy the benefits of small cells with an incremental investment to an existing large cell network. This brings many advantages but also challenges associated with managing interference. This paper looks at the techniques used to address these interference issues as they progress through standardisation into a commercial reality