مقاله انگلیسی رایگان در مورد طرح IR-HARQ برای مدولاسیون کدگذاری قطبی – IEEE 2018

Many communication channels are time-varying and unknown to the transmitter. Incremental redundancy hybrid automated repeat request (IR-HARQ) as shown in Fig. 1 is a scheme that transmits additional redundancy bits until the data bits can be reconstructed. For turbo codes (such as those used in LTE), a low rate mother code is punctured with different patterns for several transmissions. The coding scheme for enhanced mobile broadband (eMBB) in 5G uses protographbased, Raptor-like LDPC codes [10] that allow for both flexible block length and code rate adaptation. The standard defines two base matrices that offer optimized performance for different operating regimes. With cyclic redundancy check (CRC) outer codes and successive cancellation list (SCL) decoding [3], polar codes [1], [2] outperform state-of-the-art turbo and LDPC codes in the short to medium length regime. Polar-coded modulation (PCM) is discussed in [5]–[7]. The performance comparison and efficient code design methods of three polar-coded modulation schemes are presented in [8, Fig. 11]. Multilevel polar coding (MLPC) with set partitioning (SP) labeling in [5] performs best and is around 1 dB more power efficient than an AR4JA [9] LDPC code decoded with 200 iterations. A quasi-uniform puncturing (QUP) algorithm was proposed in [4] to efficiently design length-flexible polar codes, i.e., polar codes where the number of coded bits is not limited to be a power of two. In [11], a scheme the authors called “polar codes with incremental freezing” and in [12] “parallel-concatenated polar codes” is proposed. The capacity-achievability of this scheme is proved in [11] by using the nesting property. In [13], a polar code extension method is presented which outperforms the scheme in [11], [12] for finite block length. In this work, we prove that the scheme in [13] can achieve capacity asymptotically in the block length under some design constraints. In addition, a length-flexible IR-HARQ scheme based on dynamically frozen bits and QUP is proposed. This scheme is extended to polar-coded modulation with amplitude shift keying (ASK) and quadrature amplitude modulation (QAM) constellations. Simulation results show that the polar codes designed by our algorithm have similar error correction performance as directly designed polar codes. This work is organized as follows. In Sec. II, we review polar codes, PCM and QUP. We discuss existing and proposed IR-HARQ schemes in Sec. III. Sec. IV provides design examples and numerical results. The performance of the proposed scheme is compared with directly designed polar codes and 4G/5G codes [14], [15] in additive white Gaussian noise (AWGN) channels. We conclude in Sec. V.