5G wireless access solutions will support a heterogeneous set of integrated air interfaces and will exploit contiguous and wide spectrum bandwidth including Sub-6 GHz and mmWave bands and advanced beam-tracking and MIMO techniques. These will coexist with legacy (2-3G), Long Term Evolution LTE (4G) and Wi-Fi technologies to allow broader coverage and availability, higher network density and increased mobility. To further enhance spectral efficiency and throughput, small cells can be deployed, either adopting the traditional Distributed Radio Access Network (D-RAN) paradigm, where Base Band Units (BBUs) and radio units are co-located, or the more recently proposed concept of Cloud Radio Access Network (C-RAN). In C-RAN, the remote units (RUs) are connected to the Central Unit (CU) where the BBU pool is located through high bandwidth transport links known as fronthaul. Through its pooling and coordination gains, this approach can address the limitations of D-RAN, such as increased capital and operational costs, as well as limited scalability and flexibility. However, C-RAN (depending on the wireless technology adopted) may require tremendous transport bandwidth and impose strict latency and synchronisation constraints. In this context, optical network solutions can play a key role offering advanced transport capabilities.