Design And Implementation Of The Omap Platform-based Digital Trunking Terminal Protocol Stack

Digital trunking communication system is mainly used for command and dispatch communications, which has many system characteristics, such as shared common frequencies, facilities, coverage area, communications services, costs, etc, to improve services. The system also has high spectrum efficiency, confidentiality, more efficient and flexible network management and control technology, ability to support a variety of business. It has been adapted to the state's power sector as well as other wide-area-specific businesses and sectors throughout communication scheduling needs. It also has been chosen as the mobile communications platform of city emergency response system in most cities of the country. As the background and trends of national informatization and digitalization, the public security, mass transit, civil aviation, airports, ports, water conservancy and other professional sectors need to build digital trunking communication network.At present, most of the domestic digital trunking system equipments are foreign production, although which has the relatively mature technology, but expensive. As the digital trunking system is mainly used for command and dispatch communications, it can still be used in the civilian sector, but is unfit to used in national security, law enforcement departments. Therefore, developing proprietary digital trunking system, in which the protocol stack software is the key, has important practical significance.This paper first summarizes the characteristics, status and development trend of the digital trunking system, has the analysis and comparison of protocol stack software development languages and methods. Based on the overall structure and hierarchical model of the digital trunked air interface protocol stack, this paper has the analysis in technical characteristics and realized demand of the interface between the protocol layer, the original language, PDU, channel, timer, state machines, multi-tasking and other key concepts。Then, this paper has built embedded Linux systems and protocol stack software development platform based on the OMAP5912 hardware platform, completing the establishment of cross-development environment, U-Boot and Linux2.6 porting, the root file system building, analysis of OMAP dual-core booting, besides, implementing the protocol stack software development framework and its key technologiesFinally, this paper has researched and applied the DSP-side software development framework based on DSP/BIOS to achieve the lower MAC-layer functionality by using the OMAP dual-core communication mechanisms and the DSP peripheral drivers in the use of CSL. The work of this paper has passed the assessment of the early acceptance testing, achieving the half-duplex and duplex single call, group call and short message functions.