A cellular telecommunications network architecture is described where certain UEs are configured to assist the network to improve coverage in regions of poor radio conditions. In certain embodiments, appropriate UEs are selected to act as a dynamic, out-of-band coverage extensions. Network performance can thereby be improved when serving users at the cell edge (or in other poor radio condition regions of a cell). Data from UEs connected to those assisting UEs is encrypted to allow secure transit of data without requiring modification to the RAN or Core Network.