A novel method, referred to as joint multiple subpulses processing, is developed to calibrate the nonideal transfer function of radio frequency front-end and I/Q imbalance in quadrature modulate/demodulate systems simultaneously, which frequently occur in wideband Synthetic Aperture Radar (SAR) systems. Based on the time-frequency relation of the chirp signal and the analyses of the channel errors in wideband SAR, joint multiple subpulses processing method is adopted to separate the image frequency component due to the I/Q channel error. Then, the complete description of the channel error is acquired for building the correction function, which is used to correct the radar raw echo in frequency domain. The validity and capability of this method are demonstrated by the experiments of the channel error correction on the high resolution SAR system with the effective bandwidth of 500 MHz.

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Diverse application scenarios in 5G and beyond wireless communication systems have introduced various requirements in code lengths and rates of channel codes. For the decoding of polar codes, especially the belief-propagation (BP) decoding, flexible configuration of codeword length is still not involved in current decoders. In this paper, a semi-folded decoding structure is proposed which can be reconfigured to support multiple codeword lengths. Up to 16 codes can be decoded in parallel and the utilization of processing units is no less than 87.5% for various codeword lengths. The peak throughput of 19.29 Gbps can be achieved by the proposed decoder in SMIC 55 nm CMOS technology.

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