Energy-efficient machine type communication in HetNets under statistical QoS guarantees

There has been an unprecedented rise in the Internet-of-Things (IoT) in the past decade. One of the underlying reasons for this exponential growth is that IoT allows for massive machine-type communication (mMTC), which facilities machine-to-machine (M2M) communication with minimal human intervention. However, mMTC devices are characterized by resource and energy limitations, and thus require powerful and efficient power allocation methods that do not jeopardize quality-of-service (QoS) performance. In this work, a statistical QoS analysis of M2M communication in heterogeneous wireless networks is performed. We propose a communication mode selection (CMS) scheme that selects an uplink transmission link from the available candidate links based on pathloss criteria. The closed-form expressions for the Effective Capacity and effective energy efficiency (Effective-EE) of the M2M communication in the heterogeneous wireless network are derived and verified via simulations. The optimal fixed transmission rate that maximizes the Effective Capacity and Effective-EE is also analytically analyzed. Furthermore, four scenarios are adopted to study the overall Effective Capacity and Effective-EE of a two-hop M2M communication link where the transmitter and access point operate under independent and identical QoS constraints. This article also investigates the impact of circuit power and the efficiency of the power amplifier on the achievable Effective-EE of the communication link.