Low Complexity Polar Decoder for 5G Embb Control Channel

Abstract

Polar codes have become the channel coding scheme for control channel of enhanced mobile broadband in the fifth generation (5G) communication systems. Belief propagation (BP) decoding of polar codes has the advantage of low decoding latency and high parallelism but suffers from high complexity. In this paper, a low complexity BP decoder is proposed for polar codes. We reduce the computational complexity by two steps. First, the cyclic redundancy check is concatenated to the decoder in order to decrease the number iterations of the BP algorithm. Then, a threshold is proposed based on Gaussian approximation to save the computational complexity of BP nodes. If the log-likelihood ratio of a node in the tanner graph is larger than the threshold, this node is no longer updated during the rest of the decoding process. The simulation results show that the proposed scheme has a similar block error rate performance with the original BP decoder, while the computational complexity is reduced significantly. INDEX TERMS Polar codes, belief propagation, low complexity decoding, eMBB.

Novel Low Complexity BP Decoding Algorithms for Polar Codes: Simplifying on Non-Linear Operations

“…The code rate is 1/2, and the maximum number of iterations is set at 40. In those simulations, we employ the BP algorithm in [15], the MS algorithm in [17], the SMS algorithm with the scale parameter α = 0.9375 in [18], and the low complexity BP (LCBP) decoding algorithm in [32].…”

“…Firstly, special operations in the updating formula are analyzed. As can be seen from Table 4, there are two special operations in the BP algorithm, and the proposed Exp-BP decoding algorithm contains a non-linear operation according to (32). Compared with the BP algorithm, the most significant feature of the proposed QF-BP algorithm is that no special operations (ln and exp) are contained in the updating formula.…”

A Nearly Optimal Method of Polar Code Constructions for the AWGN Channel

“…In this section, firstly, the simulation results of the ABLCR from the code length 6 2 to 11 2 and DSNR 0dB to 3dB are illustrated in Fig.4. Also, it can be seen that the ABLCR with K is an approximate quadratic curve and has the maximum value.…”

An Efficient Polar Coding Scheme for Uplink Data Transmission in Narrowband Internet of Things Systems

“…Initially, from Figure 4 (b), the rightmost nodes are initialized with 0 and ∞ based on the indices of both received bits and frozen bits as Eq. (14), and the left-most nodes of the received LLR bits as Eq. (15).…”

“…The polar code is among the modern FEC coding technique that gains a lot of recognition in recent communication standards, and recommends by 3GPP standard in Release 15 as the PHY layer error correction technique for the enhanced mobile broadband (eMBB) to replaces the tail-biting convolutional codes (TBCCs) in LTE standard [14], [15]. However, recent research work considers polar codes as a candidate for mMTC, URLLC, and implemented into an ASIC chip hardware [16], [17].…”