QoS Techniques for Smart Meter Packets Transmission on LTE Networks

Abstract

The Smart Grid (SG) is defined as an intelligent electricity delivery system. It is a modern electric power that improves efficiency, reliability and sustainability of electricity services such as remote meter reading, diagnoses problems, and unauthorized customer detection. Although the native version of power grid is monitored and controlled by Supervisory Control and Data Acquisition (SCADA) system, it is implemented only at high voltage transmission. The SCADA does not cover all parts of the power grid. The SG consists of generation, transmission, distribution, and electricity consumption. All components of the SG architecture can be monitored and controlled via communication links. Smart Meter (SM) is a critical component of the Advanced Metering Infrastructure (AMI) that collects power consumption information from customer and reports it to the SG control centre. The SM is a Machine-to-Machine (M2M) communication that works without human operation. Typically there are number of SMs overloading it with billions of tiny fixed size packets containing power consumption data. All SMs need to establish a connection to transmit SM packets. The Long-Term Evolution (LTE) network has become an attractive candidate for SG communications. In spite of LTE’s growing popularity as a means of transporting SG data, it was primarily designed for high speed and high capacity mobile data traffic such as video streaming and Internet involving Human-to-Human (H2H) communication. The LTE standard can offer a huge number of SM connection. However, deploying SMs on LTE network increases the packet loss, packet delay and re-establishment as the SMs needs to access the network within a given time interval to send a small packet. This degrades the performance of the LTE network. In addition, the SM packets should be given a priority as the packets are used for power outage monitoring. Five mechanisms of the state-of-art LTE network are currently used during an overload issue such as: 1) Backoff indication; 2) Slotted access; 3) Access Class Barring; 4) Pull-based scheme; 5) Dynamic allocation of RACH resource scheme. Although these mechanisms can overcome, the issue to certain extent they increase access delay. In order to overcome this issue, this thesis introduces a Quality of Service (QoS) mechanism for the SM packets on the LTE network: 1) The uplink scheduling for SM transmission guarantees SM packet connection so that all SMs can successfully access the network. The key contribution of the proposed method is the Admission Control (AC) that controls all connections to access the eNode-B and uplink scheduling for SM queuing management; 2) In order to reduce the use of preamble signatures, SM packets are transmitted via Tracking Area Update (TAU) packet that is carried on Non-Access Stratum (NAS) message. This proposed technique can reduce preamble usage and resource consumption at the eNode-B; 3) Preamble collision issue is solved by a combination of contention and non-contention based random access procedure mechanisms. Initially, SM sends the preamble index on the contention based. If the initial access collides, then a new preamble index is given to the conflicting SM by eNode-B. With the proposed model, although SM packets are sent into network by interval time, it need not reserve the preamble for SMs at the eNode-B. The simulation results are verified by mathematical analysis. The analytical model differs with simulation result approximately 2%; and 4) LTE network performance is increased by combination of contention and non-contention based methods are combined with SM packets transmission via TAU method. The results shows the efficiency of the model in terms of lower packet delay, reduced number of packet loss, and reduced re-establishment attempts. The simulations are performed on a SM packet communication scenario. In practice, the proposed method can be applied for H2H communication at places with high intensity of smart phone connections that needs preamble signatures and causes congestions, for example stadiums, halls and outdoor events.