On the Reliability of LTE Random Access: Performance Bounds for Machine-to-Machine Burst Resolution Time

Random Access Channel (RACH) has been identified as one of the major bottlenecks for accommodating massive number of machine-to-machine (M2M) users in LTE networks, especially for the case of burst arrival of connection requests. As a consequence, the burst resolution problem has sparked a large number of works in the area, analyzing and optimizing the average performance of RACH. However, the understanding of what are the probabilistic performance limits of RACH is still missing. To address this limitation, in the paper, we investigate the reliability of RACH with access class barring (ACB). We model RACH as a queuing system, and apply stochastic network calculus to derive probabilistic performance bounds for burst resolution time, i.e., the worst case time it takes to connect a burst of M2M devices to the base station. We illustrate the accuracy of the proposed methodology and its potential applications in performance assessment and system dimensioning.Comment: Presented at IEEE International Conference on Communications (ICC), 201

Concept of intelligent system for controlling regenerative braking and using recovery energy

The issue of increasing the level of electrical energy recovered by the electric rolling stock and the efficiency of its use at the electrified sections of railways of JSC “Russian Railways” is still topical at present. This issue is considered today in the context of increasing the efficiency of the use of traction rolling stock. Increasing the energy efficiency of the transportation process by increasing the efficiency of recovery can be achieved both by the implementation of organizational decisions and through the introduction of additional equipment in the traction power supply system, for example, installation of reversible converters at traction substations or power storage devices on electric rolling stock and in the system of traction power supply, as well as other technical means, changing the parameters of the operation of sections with mandatory provision of the operability of the regenerative braking systems in the electric rolling stock. To assist in the reasoned adoption of similar and other managerial decisions, it is advisable to create an intelligent system for controlling the processes of applying regenerative braking and using recovery energy. This paper briefly reviews the main results of scientific research on the efficiency of recovery, suggests a mechanism for adapting the methods developed earlier to the system for controlling energy efficiency of recovery processes at the sections of railways

System Level Integration of Irregular Repetition Slotted ALOHA for Industrial IoT in 5G New Radio

Automation is a key part of the new industrial revolution, that will be enabled by the deployment of thousands of sensors and actuators. The flexible deployment of these devices requires wireless connectivity which is labeled as industrial internet of things, IIoT. The sporadic activity pattern of IIoT devices naturally suggest the use of random access techniques, albeit posing new and unexplored challenges for the current wireless networks. On top of the demand for new access protocols, the latency-reliability requirements further challenge the existing random access protocols. In this work we investigate the adaptation of a well known modern random access algorithm, Irregular Repetition Slotted ALOHA (IRSA) to IIoT in 5G New Radio. The key contribution of the paper is the proposed system level protocol, Adaptive-Multichannel IRSA, that can fulfill the latency-reliability requirements. On top of this, the definition and solution of the resource allocation problem as a resource efficiency optimization guarantees that the algorithm minimizes the system resources. We show that for a set of specific requirements, AMC-IRSA can fulfill the requirements in an a lot resource efficient manner. Lastly, we analyze most critical parameters to consider for integration of IRSA for 5G NR