RACH Session Initiation Procedure with Retranslations

Abstract

Due to the rapidly growing number of user’s equipments, operating in the LTE (Long-Term Evolution) mobile radio network, it became necessary to find methods to reduce the user load and signaling message’s traffic. New rules and procedures of devices communication are created to downsize network resources. This article explores the procedure for establishing a connection between mobile user’s equipment and the LTE base station. Such possible solution of transferring small data generated by machine-to-machine connections (M2M, Machine-to-Machine) was presented in the technical report TR 37.868 of the 3GPP consortium (3rd Generation Partnership Project). This approach implies the use of the random access channel (RACH) to interconnect between devices. Effective usage of the procedure for establishing a connection through a random access radio channel is based on the analysis of time-probability characteristics, such as the access success probability and failed access probability, average access delay. In this article we proposed analytical model in term of Markov chain to find these characteristics and present numerical analysis, considering collisions of preamble message, retransmissions of signalling messages and the boundary conditions on the number of possible retransmissions. The accuracy of the proposed analytical model was verified using programming environment R.