Licensed Assisted Access: Key enabling functionalities and initial results

The exploitation of unlicensed bands is now becoming a reality into the LTE-A system through the Licensed Assisted Access (LAA) working item, which was recently provided by 3GPP. This paper presents a first implementation of the key functionalities required in order to provide LAA. Our focus is on the carrier aggregation (CA) of the Unlicensed Band (UB) at 5 GHz with LTE-A bands, and since LTE-A is dominating external neighboring transmissions, particular functionalities have been proposed by 3GPP. Key functionalities are considered such as listen-before-talk (LBT), discontinuous transmission (DTX) and transmit power control. In this work, LBT and DTX for efficient carrier selection procedure are implemented. Our implementation is carried out on a LTE simulation platform and the initial results obtained, highlight new challenges for our future investigation on this topic.