Controlled Out-band Device to Device Communication in Cellular Networks Using Backup Channel in Television White Space

In this article, we address the problem of spectrum scarcity in cellular networks (CNs). We propose a backup channel (BuC) for cellular users (CUs) who are in the same macro-cell under the control of a single macro base station (eNB). This BuC operates in the television white space and is detected by the CUs through a cognitive radio energy detection channel sensing technique with a certain probability of success. When the regular channels with the cellular eNB are all occupied, the CUs within the same coverage area of the macro eNB can utilize the sensed BuC to establish a controlled out-band device-to-device link for communication. The BuC bypasses the eNB and reduces the burden on the core of the CN. This leads to improvements in the capacity of the cellular eNB. In the proposed system model, each CU and eNB is equipped with two antennas for communication in two separate bands, i.e., cellular and TV bands. Through simulations, we have observed significant reductions in the blocking probability and probability of call delays.