New Adaptive Data Transmission Scheme Over HF Radio
Abstract
Acceptable Bit Error rate can be maintained by adapting some of the design parameters such as modulation, symbol rate, constellation size, and transmit power according to the channel state.
An estimate of HF propagation effects can be used to design an adaptive data transmission system over HF link. The proposed system combines the well known Automatic Link Establishment (ALE) together with variable rate transmission system. The standard ALE is modified to suite the required goal of selecting the best carrier frequency (channel) for a given transmission. This is based on measuring SINAD (Signal plus Noise plus Distortion to Noise plus Distortion), RSL (Received Signal Level), multipath phase distortion and BER (Bit Error Rate) for each channel in the frequency list. Channel condition evaluation is done by two arrangements. In the first an FFT analysis is used where a pilot signal is transmitted over the channel, while the data itself is used in the second arrangement. Passive channel assessment is used to avoid bad channels hence limiting the frequency pool size to be used in the point to point communication and the time required for scanning and linking. An exchange of channel information between the transmitting and receiving stations is considered to select the modulation scheme for transmission. Mainly MPSK and MFSK are considered with different levels giving different data rate according to the channel condition. The results of the computer simulation have shown that when transmitting at a fixed channel symbol rate of 1200 symbol/sec, the information rate ranges from 2400 bps using 4FSK up to 3600 bps using 8PSK for SNR ranges from 11dB up to 26dB.
Downloads
References
[2] R.L. Freeman “Radio System Design for Telecommunications” John Wiley & sons Inc. 2nd Edition 1997, USA.
[3] K. A. Salim “Adaptive HF System for High Speed Data Transmission” Ph.D thesis, Al-Rasheed College of Engineering and Science, University of Technology Iraq, 2005.
[4] A.Goldsmith and S.Chua “Variable rate variable power MQAM for fading channels” IEEE Transactions on communications, Oct. 1997.
[5] M. Rostami, J. Angeja, J. Tavares and A. Navarro “HF channel modeling for real time packet transmission“ IEEE MILCOM 03 conference proceeding, 2003.
[6] F. McVerry “High Speed Data Transmission Over HF Radio Links” Ph.D Thesis, Loughborough University of Technology, 1984, UK.
[7] J. M. Torrance and L. Hanzo, “Upper bound performance of adaptive modulation in a slow Rayleigh fading channel”, IEEE Electronics letters, Volume 32, April 1996.
[8] S.Haykin “Communication Systems”, John Wiley & Sons Inc. 3th edition 1994, USA.
[9] M. D. Street and M. Darnell “Results of new Automatic Link Establishment and Maintenance Techniques for HF Radio Systems”, IEEE MILCOM97 proceeding Vol.2 p1067-1071.
[10] MIL-STD-188-141B Department of Defense Standard “Interoperability and Performance Standards for Medium and High Frequency Radio Systems”, Department of Defense, March 1999, USA.
Downloads
Published
Issue
Section
License
Copyright: Open Access authors retain the copyrights of their papers, and all open access articles are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided that the original work is properly cited. The use of general descriptive names, trade names, trademarks, and so forth in this publication, even if not specifically identified, does not imply that these names are not protected by the relevant laws and regulations. While the advice and information in this journal are believed to be true and accurate on the date of its going to press, neither the authors, the editors, nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
