Priority based VM2M communications over LTE

In this paper, we describe an VM2M overlay architecture where the overlay acts as the control channel (CCH) of VANET to transfer safety messages between vehicles and RSU. The VM2M overlay network is implemented over dedicated preamble codes in the physical layer and the medium access control (MAC) layer modeled as the IEEE 802.15.4 carrier sense multiple access (CSMA/CA) mechanism. In this paper, we implement priority based VM2M where higher priority is given to VM2M in the physical layer. To this end, VM2M preambles are transmitted with higher power than H2H. Due to large cell sizes and/or higher vehicle velocities in urban, sub-urban, and rural areas, and on highways, VM2M overlay is implemented using preamble format 2 with total duration of 2 ms. We compare the non-priority scenario, in which H2H and VM2M traffic access the base station simultaneously with the same power, to VM2M priority-based scenario where each preamble of M2M overlay is transmitted with higher power than any of non-overlay ones. The VM2M priority-based scenario is found to increase the capacity of VM2M subnetworks compared with non-priority scenario, without undue deterioration of the capacity left for H2H/SCH traffic.