Semi-Persistent RRC Protocol for Machine Type Communication Devices in LTE Networks

In this paper, we investigate the design of a Radio Resource Control (RRC) protocol in the framework of Long Term Evolution (LTE) of the 3rd Generation Partnership Project (3GPP) regarding provision of low cost/complexity and low energy consumption Machine Type Communication (MTC), which is an enabling technology for the emerging paradigm of the Internet of Things. Due to the nature and envisaged battery-operated long-life operation of MTC devices without human intervention, energy efficiency becomes extremely important. This paper elaborates the state of the art approaches towards addressing the challenge in relation to the low energy consumption operation of MTC devices, and proposes a novel RRC protocol design, namely semi-persistent RRC State Transition (SPRST), where the RRC state transition is no longer triggered by incoming traffic but depends on pre-determined parameters based on the traffic pattern obtained by exploiting the network memory. The proposed RRC protocol can easily co-exist with legacy RRC protocol in LTE. The design criterion of SPRST is derived and the signalling procedure is investigated accordingly. Based upon the simulation results, it is shown that SPRST significantly reduces both the energy consumption and the signalling overhead while at the same time guarantees the Quality of Service (QoS) requirements.