Uplink Cooperative Transmission for Machine-Type Communication Traffic in Cellular System

With the rapid development of the Internet of Things (IoT), the new challenges brought by the MTC traffic imposed a great pressure to the traditional cellular networks. The new MTC features like small-data transmission, large number of devices and deep fading channels will lead to a significant spectrum efficiency degradation and thus affect the regular Human-to- Human (H2H) communications. In this paper, we proposed a semi-centralized controlled cooperative method to improve the MTC transmission efficiency in the cellular uplink, which is backward- compatible with current LTE/LTE-A protocol and easy for implementation. Two cooperative transmission schemes based on the Device-to-Device (D2D) communications were applied, which are the Random User-Equipment (UE) Relay scheme (RUR) and the Network Coding scheme (NC). The D2D interference was analyzed based on the stochastic geometry, and 2 layers of scheduling were also considered. Intensive simulations were conducted. From the simulation results, a significant gain was achieved by the proposed method especially for the small data traffic. Also, a comparison was made between the RUR and NC schemes, and the suitable scenarios for each scheme can be identified.