Research On The Interoperability Test And VGCS Congestion Preemption For GSM-R Network A Interface

ABSTRACT: GSM-R(GSM for Railway) system plays a more and more important role in the development of the Railway mobile communication technology, which leads the direction of its evolution. As the expansibility of the network and complication of the configuration, different companies' equipments are adopted to decrease the cost, which means the interoperability becomes an urgent issue. This paper mainly focused on the interoperability test and VGCS(Voice Group Call Service) congestion preemption for GSM-R A interface, under the background of the Ministry of Railway key project which is "the interoperability test for China Railway GSM-R network".Firstly, this article introduced the architecture of GSM-R network and VGCS technology in detail, analyzed the influence of multi-level precedence and preemption technique and channel congestion problem roundly, presented the reason of the channel block, such as SDCCH and TCH. Based upon those three aspects, evaluated the per user traffic in each kind of the channel., calculated the proper channel proportion between SDCCH and TCH.Secondly, according to the interoperability test of the VGCS congestion preemption, this paper analyzed the resource preemption scheme of each company, discussed the vacancy of the protocols, and then proposed a resource preemption strategy to assure the efficiency and consistency of railway special application.Finally, the test flow of the A interface was proposed combined with the modem test manage flow, presented solutions to loss of important information. All of the improvement can make positive contributions to the development of the GSM-R network interoperability test.