Aimed at the problems that in order to meet the needs of the over-the-horizon long range communication being reliable for aircraft in super-sight-distance on far oceans and far territories, and the timefrequency double-selective fade is severe in shortwave ionospheric reflection channels, a HF wideband communication system is proposed based on single-carrier frequency division multiple access (SC-IFDMA). The proposed method is to utilize a preamble detection algorithm in combination with segmented correlation and selective RAKE reception, ensuring both the missed detection and false alarm probabilities to reach 10-4 or lower under low signal-to-noise ratio (SNR) of -15 dB. The frequency offset estimation and SNR estimation are achieved by utilizing the repetitive structure of SC-IFDMA symbols in time domain, saving the system overhead and enhancing the transmission performance. Finally, the system prototype of the semi-physical test system is built based on USRP, and the loopback test of single link is completed in the channel simulator environment. The test results indicate that the system prototype can achieve reliable Aimed at the problems that in order to meet the needs of the over-the-horizon long range communication being reliable for aircraft in super-sight-distance on far oceans and far territories, and the timefrequency double-selective fade is severe in shortwave ionospheric reflection channels, a HF wideband communication system is proposed based on single-carrier frequency division multiple access (SC-IFDMA). The proposed method is to utilize a preamble detection algorithm in combination with segmented correlation and selective RAKE reception, ensuring both the missed detection and false alarm probabilities to reach 10-4 or lower under low signal-to-noise ratio (SNR) of -15 dB. The frequency offset estimation and SNR estimation are achieved by utilizing the repetitive structure of SC-IFDMA symbols in time domain, saving the system overhead and enhancing the transmission performance. Finally, the system prototype of the semi-physical test system is built based on USRP, and the loopback test of single link is completed in the channel simulator environment. The test results indicate that the system prototype can achieve reliable communication with an adaptive rate ranging from 200 to 20 000 bps and a bit error rate below 10-5 within the SNR range of -15 to 5 dB.