d transport requirements which make the practical deployment simpler. It has turned out to be beneficial to support the same features both in macro cell and small cell. It is called feature parity. If the features, software loads and roadmaps are harmonized in macro and small cells, it will simplify the network management and optimization. In the case of RF head, the same features are available naturally since the RF head is connected to the macro cell baseband. In the case of all-in-one base station, the feature parity can be obtained by using the same hardware components in the macro and small cells. If the small cell uses different hardware and software than the macro cell, it typically leads to different features. The mobility between macro and small is normal inter-site handover in the case of all-in-one base station, which makes the mobility visible also to the core network. When the RF head is connected to the macro cell, the mobility is intra-site handover and does not impact S1 interface to the core network. The evolution to LTE-Advanced tends to be simpler with RF head with the shared baseband. Coordinated Multipoint (CoMP) transmission and reception between macro and small cells can be supported with RF head. The transport requirements between base station and RF head have major differences. The transport with the base station is called backhaul since the transmission is behind the baseband. The transport with the RF head is called fronthaul since the transmission is in front of the baseband. An example case is illustrated in Figure 5.4 with 20 + 20 MHz LTE and 2x2 MIMO. The peak rate is 300 Mbps with 20 + 20 MHz carrier aggregation, which is also the backhaul Small Cell Deployment Options 20 + 20 MHz FDD with 2 X 2 MIMO Up to 300 Mbps Backhaul Packet core All-in-one base station 14x higher transport requirements Approx 4 Gbps Fronthaul Baseband RF head Figure 5.4 Transport requirements with small base station and RF head requirement. It is also possible to use less backhaul, for example, 100 Mbps, if 