Indonesian Journal of Electrical Engineering and Computer Science Vol. 26, No. 1, April 2022, pp. 521~530 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v26.i1.pp521-530  521 Journal homepage: http://ijeecs.iaescore.com Turbo polar code based on soft-cancelation algorithm Wallaa Yaseen Alebady 1,2 , Ahmed Abdulkadhim Hamad 1 1 Department of Electrical Engineering, College of Engineering, University of Babylon, Babylon, Iraq 2 Department of Medical Instrumentation Technologies Engineering, Hilla University College, Babylon, Iraq Article Info ABSTRACT Article history: Received Nov 29, 2021 Revised Jan 20, 2022 Accepted Feb 5, 2022 Since the first polar code of Arikan, the research field of polar codes has been continuously active. Improving the performance of finite-code-length polar codes is the central point of this field. In this paper, the parallel concatenated systematic turbo polar code (PCSTPC) model has been proposed to improve the polar codes performance in a finite-length regime. On the encoder side, two systematic polar encoders are used as constituent encoders. While on the decoder side, two single iteration soft-cancelation (SCAN) decoders are used as soft-in-soft-out (SISO) algorithms inside the iterative decoding algorithm of the parallel concatenated systematic turbo polar code (PCSTPC). As compared to the optimized turbo polar code with SCAN and BP decoders, the proposed model has about 0.2 dB and 0.48 dB gains at BER=10 (-4) , respectively, in addition to 0.1 dB, 0.31 dB, and 0.72 dB gains over the TPC-SSCL32, TPC-SSCL16, and TPC-SSCL8 models, respectively. Moreover, the proposed model offers less complexity in comparison with other models, therefore requiring less memory and time resources. Keywords: PCSTPC Polar codes Soft cancellation Systematic polar codes Turbo polar codes This is an open access article under the CC BY-SA license. Corresponding Author: Wallaa Yaseen Alebady Department of Electrical Engineering, College of Engineering, University of Babylon Babylon, Iraq Email: walaa.lafta@student.uobabylon.edu.iq 1. INTRODUCTION Polar codes have changed the performance equation in the coding theory since the first polar-code of Arikan in 2009 [1]. The attention of most researchers in the coding theory field has been focused on the polar codes. The successive cancellation decoder (SC) is the first polar decoding algorithm that is proposed by Arikan in [1]. Since the polar code with the SC decoder is the first capacity-achieving code at the infinity code length. The performance of polar codes deteriorates at the finite code length and small SNR, this paper presents a turbo polar code to improve the performance of polar codes, especially at the finite-code-length and small SNR. There are several decoding algorithms suggested to improve the performance of polar codes at small and moderate code length. Tal and Vardy [2] propose the successive cancellation list (SCL) decoder. The SCL decoder offers excellent performance, especially when coupling the CRC code as a genie-code along with it [3]-[5]. At a long and moderate code length, the complexity of SCL is very high. Niu and Chen [6] propose the successive cancellation stack (SCS) to reduce the high complexity of the SCL decoder. The belief propagation (BP) decoder can also be used as a decoding algorithm for polar codes [7]. Fayyaz [8] proposes the soft successive cancellation (SCAN) decoder as a soft-in-soft-out (SISO) decoding algorithm. The other soft-in-soft-out algorithm is the soft successive cancellation list (SSCL) decoder, which offers a higher complexity as compared to the SCAN decoder [9]. Among the above decoding algorithms, only the BP, SCAN, and SSCL algorithms can be used as SISO algorithms with the turbo iterative decoding process.