timing measurements over the air, such that an eNodeB would consider one eNodeB as master in terms of timing (source selected for synchronization) and then measure and obtain the timing information from the transmission of the source eNodeB. Release 12 specifications contain signalling (over the S1-interface) which allows the SON functionality to help the over the air synchronization process by providing information of the muting pattern of the eNodeBs. By muting the detection of timing, information can be made more reliable as network planning does not normally try to ensure that eNodeBs can hear each other. Release 13 Enhancements With the Release 12 solutions as such concluded by the end of 2014, 3GPP is defining how to enhance further in Release 13 the small cells and other solutions, including carrier aggregation. Small Cell Enhancements in Release 12/13 The discussion contains approaches like uplink bearer split [3] as Release 12 supports only downlink bearer split, but uplink direction would also benefit from such a possibility. In the area of carrier aggregation, 3GPP is preparing for more spectrum availability by defining the possible number of aggregated carrier up to 32 carriers from the signalling point of view [4]. This is not really intended to go up to 32 different frequency bands but with solutions like LTE Licensed Assisted Access (LAA), as covered in Chapter 10, allow using more than four carriers on the unlicensed band. The considered 5 GHz band, in many cases, has in the order of few hundred megahertz of available spectrum. It is also expected that with new frequency bands like 3.5 GHz or the new bands from WRC-15 one operator likely have more than 20 MHz within a single frequency band. This work also covers introduction of PUCCH in SCell with carrier aggregation, as in Release 12 it is possible to send the same (or similar) L1 control information for SCell only in connection with dual connectivity but not in the Release 10-based carrier aggregation case. 4.8 Conclusions In the previous sectio