Automatic link establishment for HF radios

In the past three decades, major technologies and economic developments have been made on the telecommunication sector. HF communication has now become the main feature of the telecommunication industry. An advantage of the use of HF communication is that high frequency system is inexpensive and allows long range communication with minimal equipment requirements and easy to implement in the isolated areas as well. Frequencies ranging from 1.6 MHz to 30 MHz is called High Frequency spectrum. One of the important developments in the HF communication is Automatic Link Establishment. ALE method is widely used by the military and other organizations. In this paper we have tried to describe the implementation of ALE military standard (188-141A). This standard defines a 2G HF ALE standard. We design a communication system that allows reliable data communication over HF radio by using the Matlab environment. Our work is divided into two parts. In first part at the transmitter level, we perform the encoder to encode the data bits for error correction and detection by using the golay code. After the encoder, interleave the encoded data bits and perform the 8 array FSK modulation to transmit the data. In the second part at the receiver, we demodulated the data and then deinterleave it. After the deinterleaving we perform the decoder by using the golay decoder. At the end there is a performance analysis that comprises SNR and BER plots.