| Severely restricted bandwidth is the main reason for the low data rate of underwateracoustic communication system nowadays. OFDM is adopted by a lot of communicationstandards for its ability of resistance to multi-path interference and high spectrum utilization,which is widely used in high-speed underwater acoustic communication nowadays.The communication systems today are usually of complicated hardware, high-cost andare hard to update or upgrade. Thanks to software radio technology, the structure of thehardware can be simplified. In addition, the working frequency, bandwidth of the system,modulation method, source coding way and so on can be controlled by programming, whichstrengthens the flexibility of the system, reduces the costs and is easy to upgrade.Considering the advantages of these two technologies, a high-speed underwater acousticcommunication system based on software radio technology is designed. This paper describesthe system framework, design of software and hardware and signal processing. Among this,the hardware part is mainly combined of signal generating card, power amplifiers, underwateracoustic transducer, signal sampling card and computer. The PCI signal sampling card ofAdvantech Company and USB DAQ card of the NI company is used by this system in orderto satisfy experiment and application of different environment. This system is programed onthe VC++6.0software platform. It has friendly computer to human operating interface.Finally, we verified the reliable transferring performance of this system by testing it indifferent environment several times. The data transferring speed reaches10kbits/s using PCIacquisition card, while6.3kbits/s using USB acquisition card. In this paper, variousexperiment data are analyzed, obtaining the characteristic of channel in different environmentand distance. However, this system does not perform well in long range transferring. The errorof the received data is kind of too much. Thus, the next problem we need to figure out is howto improve the flow of signal processing and optimize the algorithms. |
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