An LTE offload solution using small cells with D2D links

Small cells are an attractive technology for offloading traffic from the macrocellular network. The first small cell architecture for offload was the femto cell, but it was not widely commercially deployed. This is because it had some drawbacks in terms of network planning such as interference handling. In this paper, we propose and study a new concept for a low-cost small cell base station (BS) for traffic offloading from the macrocellular network. The main difference from a femto cell is that the communication with the user terminal (UE, in 3GPP terminology) uses the device-to-device (D2D) radio interface. The D2D radio interface is chosen because of the close proximity between UEs and small-cell BSs and its support for opportunistic access and flexible resource allocation. The proposed concept also increases operational efficiency by reducing the network planning effort required by the projected increased deployment density of BSs to meet future traffic demand. We describe the benefits of this offload solution for LTE networks and quantify the gains via analysis and simulation.