Fifth Generation New radio (5G) is in final stage for freezing frequency band by Release 16in between 1 GHz to 43 GHz. It is also attracting much attention because of short length and long length data transfer with high speed and low latency time resulting error rate performance will degrade. Researchers are thus in continuous working on construction of more efficient regular Quasi Cyclic LDPC Code with parity check matrices of column weight two on half code rate. We suggest is a construction of regular quasi-cyclic LDPC codes with parity-check matrices of column weight two have good capability to correct bursts errors of erasures that provides benefits in terms of the error rate performance. This paper presents fundamental concepts, review study and comparative analysis which carried out by different methods of constructions QC-LDPC codes for better BER, FER calculation and improved coding gain using latest techniques.
Fifth Generation New radio (5G) is in final stage for freezing frequency band by Release 16in between 1 GHz to 43 GHz. It is also attracting much attention because of short length and long length data transfer with high speed and low latency time resulting error rate performance will degrade. Researchers are thus in continuous working on construction of more efficient regular Quasi Cyclic LDPC Code with parity check matrices of column weight two on half code rate. We suggest is a construction of regular quasi-cyclic LDPC codes with parity-check matrices of column weight two have good capability to correct bursts errors of erasures that provides benefits in terms of the error rate performance. This paper presents fundamental concepts, review study and comparative analysis which carried out by different methods of constructions QC-LDPC codes for better BER, FER calculation and improved coding gain using latest techniques.
This research investigates the simulation performance of a layered Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) decoder intended for Ultra-Reliable Low-Latency Communication (URLLC) applications in 5G New-Radio (NR) standards. The proposed work focuses on short block-length QC-LDPC codes (280,176) to meet the dual challenge of achieving ultra-low latency (<1ms) while maintaining high reliability. LDPC codes have traditionally excelled at longer code lengths; this study demonstrates the effectiveness of LDPC codes in short-length contexts through architectural optimization utilizing a layered decoding approach, which provides improved convergence speed and reduced latency compared to traditional flooding techniques. The baseline QC-LDPC decoder performs better in terms of Bit Error Rate (BER) and Block Error Rate (BLER) with only 7 iterations. For a target BLER of 10 −2 , the decoder outperforms reference shorter codes (K40, K64) with an E b /N o gain of up to 0.9 dB.
This research investigates the simulation performance of a layered Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) decoder intended for Ultra-Reliable Low-Latency Communication (URLLC) applications in 5G New-Radio (NR) standards. The proposed work focuses on short block-length QC-LDPC codes (280,176) to meet the dual challenge of achieving ultra-low latency (<1ms) while maintaining high reliability. LDPC codes have traditionally excelled at longer code lengths; this study demonstrates the effectiveness of LDPC codes in short-length contexts through architectural optimization utilizing a layered decoding approach, which provides improved convergence speed and reduced latency compared to traditional flooding techniques. The baseline QC-LDPC decoder performs better in terms of Bit Error Rate (BER) and Block Error Rate (BLER) with only 7 iterations. For a target BLER of 10−2, the decoder outperforms reference shorter codes (K40, K64) with an Eb/No gain of up to 0.9 dB.
The use of neural networks is advancing across several fields, particularly in digital communications. However, in the domain of error-correcting codes, the prevailing consensus is that Artificial Intelligence (AI) tools can, at best, match the performance of existing methods without offering any significant simplifications or improvements. As a result, the initial enthusiasm for AI-based approaches in this area has substantially declined. Recently, however, it has been demonstrated that gradient descent can be used to guide the optimization process for the code construction of unstructured Low-Density Parity-Check (LDPC) codes. In this paper, we extend and generalize this method to also optimize Quasi-Cyclic LDPC codes (QC-LDPC). More specifically, we propose to apply the new method directly to the base protograph structures of QC-LDPC codes standardized in the fifth generation (5G) New Radio (NR) framework. Experimental results reveal that, for small protograph matrices, the proposed optimization process achieves significant coding gains, with improvements of up to 1.2 dB in signal-to-noise ratio (SNR) at a target frame error rate (FER) of 10−2.
In this paper, we analyze the performances of the fifth telecommunication generation (5G) new radio (NR) quasi-cyclic (QC) low-density parity check (QC-LDPC) codes via density evolution (DE) for base graph 2 (BG2) over binary erasure channel (BEC). We derive the degree distribution of variable nodes (VND) and check nodes (CND) from the parity check matrix (PCM) of the 3rd Generation Partnership Project (3GPP) TS.38.212 and use them for DE analysis assuming of no cycle or girth. With several number of iterations, we found that 5G NR QC-LDPC of BG2 mother codes have a threshold of ∈=0.2809. The DE analysis shows that the rateless capability with the extended parity successfully correct the error for higher ∈, without suffering from the error-floor (although many degree-Is exist), but slightly loose in gap from the Shannon limit. We expect that these results are useful for the future development of QC-LDPC codes for possible improvement in the sixth telecommunication generation (6G).
There is an important breakthrough in the field of forward error correction techniques, low-density parity-check (LDPC) codes. These codes have potential to approach the Shannon limit with reliable performance on a given channel, known as the channel capacity. Recently, researchers pay much more attention towards LDPC codes because its performance is better than Turbo codes. However, the LDPC code is the best when it is an irregular code and uses with a very large block-length. Although, the short block-length LDPC codes perform not so well, they are easy to implement in various practical applications. Therefore, there is still a demand of new development on the encoding side of LDPC codes for various ranges of code rate and code length so as to capable of using in many applications.This thesis proposes the development of quasi-cyclic (QC) LDPC codes for column weight 3. In the first part of this thesis, we propose a new construction algorithm of QC-LDPC codes for medium to large block-length by combining QC-LDPC codes of small block-length as their component codes, via Chinese remainder theorem (CRT). Such component codes were constructed by permuting each column block sequentially to attain the desire local girth. After combining all component codes to generate an expanded parity-check matrix, the resulting girth is greater than or at least equal to the maximum girth of the component codes. Simulation results show that our proposed construction method of the parity-check matrix significantly outperforms the other well-known existing methods in terms of low error-floor, simple structure, high performance, and can reduce encoding complexity.In addition, this thesis also proposes two new construction methods for QC-LDPC codes, namely a base matrix method and a subtraction based method. A base matrix based method is a simple, less computational complexity method for constructing the exponent matrix (3, K) of girth 8, 10 and 12 of QC-LDPC codes. Another method is a subtraction method, which has a similar exponent matrix as a base matrix method and has a girth at least 8. Results indicate that the LDPC codes constructed from these two methods have flexibility for arbitrary block-column length K and have a similar BER performance if compared to existing methods.
Quasi Cyclic Low Density Parity Check codes (QC-LDPC) is proposed to reduce the complexity of the Low Density Parity Check codes (LDPC) further while obtaining the similar performance. Our proposed QC-LDPC presents an improved construction of circulant sub-matrices based QC-LDPC at high SNR. The proposed construction yields a performance gain of about 1 dB at a 0.0003 bit error rate (BER). Proposed code is tested on 4 types of decoding algorithm and compared. Proposed algorithm is also compared with the existing QC-LDPC and the proposed approach outperforms the existing one at high SNR. Simulation is also performed varying the number of horizontal submatrix and the result shows that the parity check matrix with smaller horizontal concatenation shows better performance.