Research And Software Realization Of 3G HF Frequency Selection And Link Establishment System

Shortwave communication has many nice features that are not possessed by other means of communication, and its invulnerable property of channel is especially favored by many users. This article is a paper about the research and implementation of shortwave communication. The research content of this article is derived from the scientific research project "the research of frequency selection and link establishment technology for HF communication ". As the technology updates and actual needs of users become increasing high, the development of the third generation shortwave frequency selection and line establishment system is established in laboratory. This paper researches the protocol of the third generation shortwave frequency selection and link establishment system and implements the communication controlling software.The major work and result are as follows:1. By researching the communication controlling protocol, we make some amendments and improvements for it, namely, using partial reserved 4bit in data frame as package number, theoretically analyze the cause of revision and the performance improvement brought by it. The revision increases the success rate of chain building, decreases system’s mean time to build chain, and enhances the flexibility of link establishment system.2. Because the previous Win CE implementing project cannot meet the real time requirement of the system, the project of bare computer plus interrupt handling is determined ultimately. The author designs and implements the general architecture and the related interface protocols of the communication controlling software, adopts the bare computer plus interrupt handling to accomplish it in Keil environment.3. By setting up indoor testing platform, we make module testing, connectivity testing and performance testing for the system. Comparing the actual value and theoretical value of both the mean time to build link and the success rate of building time, it is found that the revision for the frame improves the performance of the system, the design of communication controlling protocal is feasible, and the implementing project of bare computer plus interrupt is right.