| HF communication is a kind of radiocommunication working at 3~30MHz(wavelength 100~10m). It is a common method for long-distance communication for certain users due to the capabilities of long-distance and indestructible communication. Shortwave frequency resource is quite limited. It is easily affected by the movement of ionosphere as well. Therefore, reasonable frequency forecast and assignment is required for HF communication. So far, both domestic and foreign mature software products are mainly focused on shortwave frequency forecast, but none of them has implemented frequency assignment. In this paper, a HF frequency forecast and assignment system is developed for certain users.According to the users’ practical requirements, a frequency forecast and assignment model for HF communication is established at the circumstance of large numbers of wireless equipment intensively distributed and a shortwave frequency forecast and assignment system was developed accordingly. The contributions of this paper are as following.1. According to the transmission models of ITU(ITU-RP.1239ã€ITU-RP.1240), a practical model was built to forecast shortwave frequency and carry out electromagnetic compatibility(EMC) analysis and electromagnetism environment test analysis to the optimum working frequency bands. A shortwave frequency assignment model was also developed based on the forecast results. The paper can be regard as a complement on frequency assignement to related research areas which mainly focused on frequency forecast.2. Based on the model of shortwave frequency forecast and assignment, by adopting C/S framework, VC++ and database technology, a frequency assignment system based on shortwave frequency forecast was implemented. The system is composed of three functionality modules, which are shortwave frequency forecast and assignment, frequency resources management and system management. The module of shortwave frequency forecast and assignment works as a guidance to lead the users to forecast and assign frequency step by step and then finally confirm the frequency assignment scheme in the form of shortwave liaison document for sharing and consulting. The modules of frequency resource management and system management support the function of management and maintenance of shortwave frequencies, user authorities and other data.The system was tested and examined. All functions and performances have achieved expected requirements. This system has been delivered to certain users for probation. The result of probation indicates that the system is robust and qualified for practical using. The system can improve HF communication and satisfy the requirement of long-distance communication for certain users.Management and maintenance of data of wireless station and equipment will be further designed and implemented to meet the increasing requirement of users. The research of data harmonization of this system and frequency management integrative system will be carried out and hence to enhance the compatibility of this software. |
