Detection and Impact of the Hidden Node Problem in LAA-WiFi Coexistence Scenarios

LTE operation in the unlicensed spectrum emerges as an alternative to increase the capacity of 4G wireless networks. 3GPP has finished the standardization of Licensed Assisted Access (LAA) for LTE operation in 5 GHz unlicensed spectrum, this solution makes use of Listen Before Talk (LBT) algorithm which is pretty similar to Wi-Fi medium access control (MAC) protocol. In this context, the hidden node problem in heterogeneous networks (LAA/Wi-Fi) is a topic that must be addressed in order to avoid or reduce the degradation of the network. Finding out hidden nodes and understanding the main metrics that reveals how the network performance gets affected by its presence inside LAA networks is an issue that, if managed correctly, can make possible to take intelligent decisions for the sake of the efficiency of LAA and Wi-Fi network. In order to understand how these metrics evolve, we have proceeded to analyze LAA/Wi-Fi networks with the presence of hidden node(s) through a simulation tool. The results demonstrate that using the distribution of Channel Quality Indicator (CQI) metric makes possible to detect nodes in hidden areas, likewise that there are a set of metrics associated to hidden nodes that describes how much a network`s performance get reduced.