Voice over IP to ISDN gateway via LTE access

The relevance of article is due to the developing and increasing of tele-communication network kinds and access technologies in railway infra-structure including Long-Term Evolution (LTE). An important practice task is to realize interaction between both developing and existing networks such as Voice over Internet Protocol (VoIP), Integrated Services Digital Network (ISDN), etc. The object of the study is access gateway to the railway opera-tion network via LTE access for fixed and mobile subscribers. This solution might provide access to existing ISDN for a distance more than 1 km without signal regeneration and installation of additional expensive equipment, re-dundant in the case of access by a small number of subscribers. Thus, this study is aimed at hardware and software based solutions of the VoIP to ISDN gateway via LTE construction system. The paper proposes test of the gateway operation, as well as experiments using IP and ISDN protocol an-alyzers to describe the interaction of network signaling, estimated the sizes of data transmission packets for several types of codecs. Authors note that further research of the device should be carried out using the QoS criteria depending on the operating conditions of the LTE network (signal level, object speed, presence of obstacles and signal reflections).