On Efficient Scheduling of H2H Traffic and Reducing Signaling Overhead due to Uplink Small Data M2M Traffic in LTE-A Networks

Large coverage and global connectivity makes cellular networks as preferred choice for internet of things (IoT). Machine-to-machine (M2M) communications deal with communication and networking aspects of IoT. Since, cellular networks are optimized to support human-to-human (H2H) communication (e.g., Voice calls, Internet), incorporating M2M communication may affect the QoS of the former. Also, the large number of M2M devices incur significant signaling overhead on both core network (CN) and radio access network (RAN). In LTE-A networks, EPS bearer establishment procedure to connect a device to the PDN gateway involves several signaling messages exchange between the device and the network. M2M devices mostly generate traffic of low volume and less frequent, in nature. So, it is very uneconomical to have rigorous signaling messages exchange to send few bytes of data. In this paper, we first studied class based dynamic priority (CBDP) algorithm Giluka et al. (in: Proceedings of IEEE WF-IoT, 2014), which is a delay aware radio resource scheduling algorithm to support uplink M2M traffic with minimal effect on QoS of uplink H2H traffic. Further, we modeled the optimal behavior of the CBDP algorithm and compared with its behavior in practical scenarios. Apart from this, we propose a lightweight EPS bearer establishment procedure to be followed by M2M devices sending small data, in which M2M small data is piggybacked with control message. Further, in the same procedure, redundant signaling messages for small data transmission (SDT) are carefully removed preserving the security aspects of the system. To ensure security for the small data transmitted, a new insightful technique of replacing authentication with confidentiality is conceived. With this, we propose an enhanced version of CBDP algorithm, named as Non-SDT-CBDP algorithm or NSDT-CBDP algorithm, which schedules resources only to H2H and NSDT-M2M flows while SDT-M2M flows are piggybacked with Message 3 (MSG-3) of lightweight EPS bearer establishment procedure. The simulation results show performance gain of NSDT-CBDP over CBDP, specially for class-3 M2M and class-4 H2H. The NSDT-CBDP algorithm show percentage reduction in packet loss ratio by 25% for class-3 M2M, percentage reduction in end-to-end delay by 11 and 19% for class-4 H2H and class-3 M2M, percentage gain in throughput by 27 and 19% for class-4 H2H and class-3 M2M. Apart from this, NSDT-CBDP algorithm is able to allocate 12% more RBs to H2H devices in comparison to CBDP algorithm.