 inter-site carrier aggregation provides over 50% gains at low to medium loads for cell edge performance and over 30% for the median throughput. It is observed that the handover failures are significantly lower with dual connectivity. The improved mobility comes from always having the primary cell at the macro layer, while utilizing the small cells by configuring those as secondary cells. The chapter also illustrated that advanced inter-cell interference coordination solutions can increase the throughputs in ultra dense small cell networks. The proactive time-domain solution gives up to 20-25% gain and the reactive carrier-based solution even more. The chapter discussed the base station power-saving options in HetNet scenarios as well as multivendor deployment aspects. References [1] S. Barbera, P.H. Michaelsen, M. Saily, and K. Pedersen, "Mobility Performance of LTE Co-channel Deployment of Macro and Pico Cells', IEEE Proceedings WCNC, Paris, France, 1-4 April 2012, pp. 2890-2895. [2] S. Barbera, P. H. Michaelsen, M. Saily, and K. Pedersen, 'Improved Mobility Performance in LTE Co-channel HetNets Through Speed Differentiated Enhancements', IEEE Proceedings Globecom, Workshop on Heteroge- neous, Multi-hop, Wireless, and Mobile Networks, Anaheim, CA, December 2012. [3] S. Hämäläinen, H. Sanneck, and C. Sartori, editors. LTE Self-Organising Networks (SON), 1st ed., John Wiley & Sons, Ltd (2012). [4] A. Prasad, O. Tirkkonen, P. Lunden, O. N. C. Yilmaz, L. Dalsgaard, and C. Wijting, 'Energy Efficient Small Cell Discovery Techniques for LTE-Advanced Heterogeneous Network Deployments', IEEE Communications Magazine, 51, 72-81 (May 2013). [5] 3GPP TR 36.872, 'Small Cell Enhancements for E-UTRA and E-UTRAN - Physical Layer Aspects', v.12.1.0, 2013. [6] C. Coletti, L. Hu, H. Nguyen, I. Z. Kovacs, B. Vejlgaard, R. Irmer, and N. Scully, 'Heterogeneous Deployment to Meet Traffic Demand in a Realistic LTE Urban Scenario', IEEE Proceedings on Vehicular Technology Conference (VTC Fall), September 2012. [7] 3GPP TR 36.839, 'Evolv