5G technology new radios (5G NR) require high-speed decoders that operate on highly irregular low-density parity-check (LDPC) codes.LDPC decoders have gained significant attention due to their excellent error correction performance.This study evaluates on different algorithms and scheduling techniques used for LDPC decoders.The analysis highlights that Min-Sum-based approaches can reduce the computational complexity compared to the basic sum-product algorithm, while the normalized and extended Min-Sum algorithms provide a better trade-off owing to their accurate value assumptions.Furthermore, different scheduling methods are implied for MS to improve speed and reduce latency.This study provides a comparative analysis of the algorithms and architectures that yield high throughputs without compromising performance efficiency.The LNMS algorithm with a data-level rescheduling technique resolves data dependency issues.This resolves the complexity of CN and VN and improves the throughput, making it suitable for 5G NR applications.The decoded throughput achieved with this scheduling is 7.0 Gbps.This throughput is achieved by maintaining the standard parameters and worst case parameters, such as four/eight iterations, BG1, and a code rate of 0.8/0.5.The evaluated architectures are implemented on Field Programmable Gate Array (FPGA) devices.This study aids in selecting the optimal architecture and scheduling techniques for LDPC decoders by considering various performance standards to deploy wireless networks in 5G and beyond.
5G technology new radios (5G NR) require high-speed decoders that operate on highly irregular low-density parity-check (LDPC) codes.LDPC decoders have gained significant attention due to their excellent error correction performance.This study evaluates on different algorithms and scheduling techniques used for LDPC decoders.The analysis highlights that Min-Sum-based approaches can reduce the computational complexity compared to the basic sum-product algorithm, while the normalized and extended Min-Sum algorithms provide a better trade-off owing to their accurate value assumptions.Furthermore, different scheduling methods are implied for MS to improve speed and reduce latency.This study provides a comparative analysis of the algorithms and architectures that yield high throughputs without compromising performance efficiency.The LNMS algorithm with a data-level rescheduling technique resolves data dependency issues.This resolves the complexity of CN and VN and improves the throughput, making it suitable for 5G NR applications.The decoded throughput achieved with this scheduling is 7.0 Gbps.This throughput is achieved by maintaining the standard parameters and worst case parameters, such as four/eight iterations, BG1, and a code rate of 0.8/0.5.The evaluated architectures are implemented on Field Programmable Gate Array (FPGA) devices.This study aids in selecting the optimal architecture and scheduling techniques for LDPC decoders by considering various performance standards to deploy wireless networks in 5G and beyond.
The development of the Fifth Generation (5G) New Radio (NR) provides several significant advantages when compared to the fourth generation (4G) Long Term Evolution (LTE) in mobile communications. Due to the outstanding characteristics of Low-Density Parity-Check (LDPC) codes such as high decoding performance, high throughput, low complexity, they have been accepted as the standard codes for the 5G NR. In this paper, we propose two LDPC decoding algorithms: Hybrid Offset Min-Sum (HOMS) and Variable Offset Min-Sum (VOMS), which are aimed at improving the error correction performance. The main idea of the HOMS/VOMS algorithm is to apply modified factors to both variable-nodes and check-nodes updated processing in order to compensate the extrinsic messages overestimation of the MS-based algorithms and increase the protection ability for degree-1 variable-nodes. The simulation results show that at the Bit-Error-Rate (BER) of 10-5, the proposed HOMS/VOMS algorithm achieves the decoding gain up to 0.2 dB compared to the Offset Min-Sum (OMS) algorithm, with a slight increase in decoding complexity.
The paper presents a detailed analysis of the minsum decoding algorithm as applied to low-density parity-check (LDPC) codes used in 5G new radio (NR) systems. With the increasing demand for higher data rates and improved reliability in next-generation wireless communications, LDPC codes have emerged as a pivotal component in 5G NR's coding strategy. The minsum algorithm, known for its simplicity and efficiency in message passing, is evaluated in the context of its performance and practical implementation for these codes. Minsum decoding reduces complexity by approximating the soft-decision values using the minimum of the incoming messages, rather than applying the more computationally expensive operations such as hyperbolic tangent functions. In the context of 5G NR, this approximation makes minsum decoding particularly attractive for hardware implementation, providing a good trade-off between error-correction performance and computational efficiency. The algorithm iteratively updates messages passed along the edges of the Tanner graph, leveraging the sparsity of LDPC codes. This abstract reviews the relevance of minsum decoding to 5G NR LDPC codes, emphasizing its role in balancing performance with low computational requirements, critical in mobile and high-throughput applications.
This paper presents a pipelined layered quasi-cyclic low-density parity-check (QC-LDPC) decoder architecture targeting low-complexity, high-throughput, and efficient use of hardware resources compliant with the specifications of 5G new radio (NR) wireless communication standard. First, a combined min-sum (CMS) decoding algorithm, which is a combination of the offset min-sum and the original min-sum algorithm, is proposed. Then, a low-complexity and high-throughput pipelined layered QC-LDPC decoder architecture for enhanced mobile broadband specifications in 5G NR wireless standards based on CMS algorithm with pipeline layered scheduling is presented. Enhanced versions of check node-based processor architectures are proposed to improve the complexity of the LDPC decoders. An efficient minimum-finder for the check node unit architecture that reduces the hardware required for the computation of the first two minima is introduced. Moreover, a low complexity a posteriori information update unit architecture, which only requires one adder array for their operations, is presented. The proposed architecture shows significant improvements in terms of area and throughput compared to other QC-LDPC decoder architectures available in the literature.
In this paper, we present a new microarchitecture of low-density parity-check (LDPC) decoder compliant to the specifications of 5G new-radio (NR) wireless-communication standard. This work suggests a fully-parallel VLSI architecture for this decoder to achieve high throughput. The digital architecture of internal modules as well as system-level design of the LDPC decoder are presented here. The comprehensive bit-error-rate (BER) performance analyses of our LDPC decoder has been performed in additive-white Gaussian-noise (AWGN) channel environment for various number of decoding iterations and bit-quantization. It delivers a BER of 10-6at 1 dB of Eb/N0while decoding for 10 iterations with 7-bits quantization. In addition, FPGA implementation and post-route simulation of the proposed LDPC decoder are carried out that can decode an encoded LDPC code of 26112 code-length for 1/3 code-rate. Our decoder has achieved a throughput of 2.9 Gbps while operating at a clock frequency of 102 MHz. These implementation results are compared with the reported works where our design delivered 20× better throughput compared to the state-of-the-art LDPC decoders.
This novel research introduces a game-changing architecture design for Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) decoders in Fifth-Generation New-Radio (5G-NR) wireless communications, specifically designed to meet precise specifications and leveraging the layered Min-Sum (MS) algorithm. Our innovative approach presents a fully parallel architecture that is precisely engineered to cater to the demanding high-throughput requirements of enhanced Mobile Broadband (eMBB) applications. To ensure smooth computation in the MS algorithm, we use the Sub-Optimal Low-Latency (SOLL) technique to optimize the critical check node process. Thus, our design has the potential to greatly benefit certain Ultra-Reliable Low-Latency Communications (URLLC) scenarios. We conducted precise Bit Error Rate (BER) performance analysis on our LDPC decoder using a Hardware Description Language (HDL) Co-Simulation (MATLAB/Simulink/ModelSim) for two codeword rates (2/3 and 1/3), simulating the challenging Additive White Gaussian Noise (AWGN) channel environment.
In this work, iterative decoders for Low-Density Parity-Check (LDPC) codes are analyzed and optimized for low computational complexity. LDPC block codes are now widely used in industry standards such as Wi-Fi or 5G New Radio (NR). Hence, there is a strong need for decoder concepts suitable for hardware designs. In addition, terminated LDPC convolutional codes are promising candidates for next-generation communication systems. The main theme of this work is to investigate low-overhead strategies for reducing the computational complexity of iterative decoders. Two aspects are considered for fast decoding of the LDPC block codes in 5G NR. Firstly, an efficient but simple-to determine update schedule for the iterative decoding process, i.e., the sequence of updates on different parts of a codeword, is proposed. Secondly, Early Termination (ET), i.e., an option to stop decoding before a maximal number of iterations is exhausted, is improved in two ways: On the one hand, a partial evaluation of the code’s Parity-Check (PC) equations speeds up the detection of valid codewords. On the other hand, a novel criterion detects when the decoding process is unlikely to converge and stops the decoding before a lot of resources are wasted on futile iterations. The combination of all techniques results in a decoder with significant reduction of the computational complexity compared to a decoder without these methods. Still, only few additional residual decoding errors are produced. This work also contains an analysis of various aspects of a Windowed Decoder (WD), which is a specialized decoder design for LDPC convolutional codes. A WD can be configured in even more ways than a decoder for block codes. The analysis in this work assumes a normalization of the computational complexity to a certain maximal value. With this setup, it is shown that a larger size of the decoding window may be preferable over a smaller size to minimize the computational complexity. Furthermore, various window update strategies (determining in which way the code symbol reliabilities are updated in each window) and variations of ET are compared to identify a well-suited WD configuration. Lastly, strategies with Dynamic Scheduling (DS) are considered to further reduce the computational complexity. A novel fixed approach derived from several DS strategies performs well without actual dynamic knowledge of the decoder state. All in all, the optimized WD configuration halves the computational complexity of a block decoder while maintaining an acceptable loss in the decoding performance measured by the number of residual decoding errors. A comparison of systems with Hybrid Automatic Repeat reQuest (HARQ) expands the scope of this work into the domain of error control by retransmissions. The analyzed systems make use of the decoder output, e.g., the final code-symbol reliabilities, to assemble dynamic retransmissions that are as short as possible and contain specifically selected code symbols. These systems stand in contrast to contemporary implementations of HARQ that only use imprecise feedback messages. Still, some compatibility with existing systems is achieved by assuming a limited feedback channel, which requires clever compression of the feedback information. A novel HARQ system is proposed, which evaluates the code’s PC equations to avoid the computational overhead of soft-value processing. The throughput with the proposed system is found to be improved compared to a reference system that evaluates code-symbol reliabilities. Finally, approximations of the accurate message-update rules of the Sum–Product Algorithm (SPA) are analyzed. With fixed-point arithmetic, Look-Up Tables (LUTs) are a promising approach to approximate functions that are costly to compute. It is shown that an optimized LUT with just nine entries can be used in a fixed-point decoder such that the decoding performance is close to that of a floating-point decoder with accurate message updates.