Realization of CDMA-based IoT Services with Shared Band Operation of LTE in 5G

5G network is envisioned to deploy a massive Internet-of-Things (IoTs) with requirements of low-latency, low control overhead and low power. Current 4G network is optimized for large bandwidth applications and inefficient to handle short sporadic IoT messages. The challenge here spans multiple layer including the radio access and the network layer. This paper focus on reusing CDMA access for IoT devices considering event-driven and latency sensitive traffic profile. We propose a PHY/MAC layer design for CDMA based communication for low power IoT devices. We propose and evaluate coexisting operation of CDMA based IoT network in presence of the exiting LTE network. Our proposed design will integrate IoT traffic with legacy system by minimal modification at the edge network, essentially eNodeB. We show that the underlay CDMA IoT network meets IoT data traffic requirements with minimal degradation (3%) in the LTE throughput. We also implement the proposed design using Software Defined Radios and show the viability of the proposal under different network scenarios.