Radio Resource Management Strategies For GSM-R Trunked Dispatch Services

ABSTRACT:GSM-R trunked dispatch services are widely used as advanced voice service in railways, marshalling yards and large stations, and the quality of these services has direct impact on the ecurity and reliability of the railway dispatching communication. Trunked dispatch services have great demands for frequency resource, but only bandwidth of 4MHz frequency is available for GSM-R network. Therefore, in order to provide service to as many subscribers as possible with the limited resource under the condition of qualified coverage and service, radio resource management strategies are studied in this paper based on test results.Two implementations of dynamic VGCS that VGCS based on Unstructured Supplementary Service Data and dynamic VGCS based on Short Message are proposed in this paper to solve the problems of static VGCS. In contrast to dynamic VGCS based on Short Message, dynamic VGCS based on USSD has better quality for its good solution to make up the defects of static VGCS and to improve the timeliness and convenience of railway dispatching communication.Appropriate allocation strategies of VGCS and VBS traffic channel are proposed by improving the standard strategies given by 3GPP in this paper. The new strategies not only provide higher resource utilization but also realize better subscriber management of network by the real-time interaction between broadcast listeners and speaker. In addition, the release process after the resource preemption on the subscriber interface in Enhanced Multi-Level Precedence and Pre-emption service is studied in this paper and it is also verified.In the last part of this paper, the signaling process of GSM-R trunked dispatch services are verified based on the research about the related test cases in the GSM-R verification test on Beijing-Kowloon line in order to provide guidance for engineering practice.