Joint tracking of groups of users with uplink reference signals

In cellular networks user equipment (UE) need to be tracked so that they can be reached by incoming data and to keep context information such as encryption keys available for UE originated transmission. Typically UEs measure reference signal transmissions that are broadcasted by the network, and report to the network based on some criterion that allows the network to know the UE location with sufficient accuracy. An alternative approach is to let the UEs send out reference signals that the network can detect to track the UE location. This reduces the need for the UEs to measure and report, while it requires some resources for uplink transmission. In this paper we propose and evaluate a solution for jointly tracking groups of UEs that are moving together. The results show that UEs can be tracked efficiently with low resource consumption.