Military Radio Communication Equipment Self-adapting Modulate Technical Research

Software wireless is a new revolution in wireless communication field, it start from a developed ideas of American SpeakEasy Station, and have special indication signification for radio communication especially for the design and develop of government communication equipment. The base theory is to construct a open, standardization, modularization general hardware platform, achieves as much as possible wireless communication functions, such as work frequency spectrum, modulate/demodulate type, encrypt mode, communication protocol and so on with software; liberated from oriented radio design method which based on hardware, and usage. The objective of software wireless is to realize multiple frequency spectrum, multi-system, multi-mode acceptance and transmission, achieve interconnection between equipment.Improvement of software wireless technique provides a new thought for communication system design. A very important characteristic among them is to support disposal of multi-mode modulation/demodulation, that means, when communication system working, many kinds of modulation way self-adapting adjust according to system status, modulation mode receiver which transmitter setup didn't set before, after receiver received signal, recognized modulation mode which the transmitter adopt by using modulation mode automatic recognize function, and call corresponding modulation mode or set general modulation mode parameter to realize demodulation.Multi-mode modulation/demodulation function is one of the key technologies of software wireless, and has important react on nowadays communication system design. In some broadband communication system, for example the wireless LAN which combines with OFDM technology and wireless MAN, different circumstance and using place will make different requirement to communication system, its modulation way will adjust according to change of channel condition. To be a big application network, its hardware platform can design unified, but adopt different modulation/demodulation algorithm according to different application situation.We put forward a self-adapting bit and power allocates arithmetic which maintan a certain transmission rate in the OFDM system. This arithmetic appilied in multi-route frenquency selectivity fading channel of superpose Gs white noise. Simulation result shouws, this arithmetic erro rate performance in advance of geometric proportion geometric proportion obviously, and it is suited to enhance frequency spectrum utilance and quality of serves in mobile communication.OFDM system was imeplement on TMS320C6416 DSP processor by research, discusses the software development procedure of whole baseband system, dissertates programming thoughts, explains mutli-channel serial port and DMA which applicated in system, and key code of programme. A lot of simulation indicates that the system performance should improve clearly if we adopt self-adapting technology .