Performance evaluation of TD-LTE in VHF-band for large coverage public broadband communications system

Agile and reliable measures for voice and video transmission are required for extremely highly-public and highly-urgent services by public institutes such as police department, fire department, and emergency medical service. For this purpose, a part of VHF-band was allocated to the public broadband communications (PBB) and a domestic standard of ARIB STD T-103 was standardized for the PBB. ARIB STD-T103-compatible hardware and systems have been already developed and achieved long-range transmission of voice and video in harsh transmission environment such as the mountain area. On the other hand, this ARIB STD T-103-compatible hardware has a problem about its expensive cost. For a further promotion of the PBB system, the reduction of the hardware price becomes important fact. Under such a background, the introduction of TD-LTE system for the VHF-band has been considered in Japan. The LTE system has the potential for application to the long-range communication system at low cost; however, there is no report on the LTE system evaluation in VHF-band PBB environment. In this paper, we investigate the transmission performance of the 5 MHz bandwidth TD-LTE system in conformity to the Japanese VHF-band requirement by evaluating bit error rate (BER) and block error rate (BLER) with several multi-path fading channel models.

I. Introduction

In public wireless communications system currently used in public institutes (e.g., police, firefighting, and emergency medical service), voice transmission is mainly used. These public institutes require agile and reliable measures for voice and video transmission urgently to confront unprecedented catastrophe such as the Great East Japan Earthquake on March 2011. Under these circumstances, a part of the VHF-band used for terrestrial analog television broadcasting until July 2011 was re-assigned to the public broadband communications (PBB) system for realizing a safe and secure society in Japan [1]. Due to the extremely important purpose of safety and security, technical standards have been established to ensure quality of service (QoS) required for video transmission, and communication distance of several kilometers with reliable connectivity [1]. As the Japanese domestic standard for PBB systems, the ARIB STD-T103 standard has been completed in March 2010 [2]. ARIB STD-T103 standard-based systems have already been developed, and it has been reported that long-distance transmission can be achieved in not only urban area but also harsh transmission environment such as mountain area by computer simulation [3] and demonstration experiments [3]–[8]. However, the ARIB STD-T103-based system has a problem that the manufacturing cost of the radio equipment is expensive. To further spread the PBB system, it is necessary to reduce the cost of the radio equipment.