Hanho Lee

High-speed VLSI architecture for parallel Reed-Solomon decoder

This paper presents high-speed parallel Reed-Solomon (RS) (255,239) decoder architecture using modified Euclidean algorithm for the high-speed multigigabit-per-second fiber optic systems. Pipelining and parallelizing allow inputs to be received at very high fiber-optic rates and outputs to be delivered at correspondingly high rates with minimum delay. A parallel processing architecture results in speed-ups of as much as or more than 10 Gb, since the maximum achievable clock frequency is generally bounded by the critical path of the modified Euclidean algorithm block. The parallel RS decoders have been designed and implemented with the 0.13-/spl mu/m CMOS standard cell technology in a supply voltage of 1.1 V. It is suggested that a parallel RS decoder, which can keep up with optical transmission rates, i.e., 10 Gb/s and beyond, could be implemented. The proposed channel = 4 parallel RS decoder operates at a clock frequency of 770 MHz and has a data processing rate of 26.6 Gb/s.

A high-speed four-parallel radix-2 4 FFT/IFFT processor for UWB applications

In this paper, we present a novel high-speed low- complexity four data-path 128-point radix-24 FFT/IFFT processor for high-throughput MB-OFDM UWB systems. The high radix radix-24 multi-path delay feed-back (MDF) FFT architecture provides a higher throughput rate and low hardware complexity by using a four-parallel data-path scheme. A method for compensating the truncation error of fixed-width Booth multipliers with a Dadda reduction network is also employed, which maintains the input and output at 10-bit width with 33 dB SQNR. This method leads to reduction of truncation errors compared with direct-truncated Booth multipliers. The proposed FFT/IFFT processor has been designed and implemented with 0.18-mum CMOS technology and a supply voltage of 1.8 V. The proposed four-parallel FFT/IFFT processor has a throughput rate of up to 1.8 Gsample/s at 450 MHz while requiring much smaller hardware complexity.

VLSI design of Reed-Solomon decoder architectures

This paper presents VLSI implementations of an 8-error correcting (255, 239) Reed-Solomon (RS) decoder architecture for the optical fibre systems. We present the RS decoders using Euclidean and modified Euclidean algorithms which are regular and simple, and naturally suitable for VLSI implementation. We investigate hardware complexity, clock frequency and data processing rate for those RS decoders. The RS decoder based on the modified Euclidean algorithm operates at a clock frequency of 75 MHz and has a data processing rate of 600 Mbits/s in 0.25-/spl mu/m CMOS technology with a supply voltage of 2.5 V.

A high-speed low-complexity Reed-Solomon decoder for optical communications

This paper presents a high-speed low-complexity Reed-Solomon (RS) decoder architecture using a novel pipelined recursive modified Euclidean (PrME) algorithm block for very high-speed optical communications. The RS decoder features a low-complexity key equation solver using a PrME algorithm block. The recursive structure enables the novel low-complexity PrME algorithm block to be implemented. Pipelining and parallelizing allow the inputs to be received at very high fiber-optic rates, and outputs to be delivered at correspondingly high rates with minimum delay. This paper presents the key ideas applied to the design of an 80-Gb/s RS decoder architecture, especially that for achieving high throughput and reducing complexity. The 80-Gb/s 16-channel RS decoder has been designed and implemented using 0.13-/spl mu/m CMOS technology in a supply voltage of 1.2 V. The proposed RS decoder has a core gate count of 393 K and operates at a clock rate of 625 MHz.

A High-Speed Two-Parallel Radix-24 FFT/IFFT Processor for MB-OFDM UWB Systems

This paper presents a novel high-speed, low-complexity two-parallel 128-point radix-24 FFT/IFFT processor for MB-OFDM ultrawideband (UWB) systems. The proposed high-speed, low-complexity FFT architecture can provide a higher throughput rate and low hardware complexity by using a two-parallel data-path scheme and a single-path delay-feedback (SDF) structure. The radix-24 FFT algorithm is also realized in our processor to reduce the number of complex multiplications. The proposed FFT/IFFT processor has been designed and implemented with 0.18-μm CMOS technology in a supply voltage of 1.8 V. The proposed two-parallel FFT/IFFT processor has a throughput rate of up to 900 Msample/s at 450 MHz while requiring much smaller hardware complexity and low power consumption.

A High-Speed Low-Complexity Modified

This paper presents a high-speed low-complexity modified radix-25 512-point fast Fourier transform (FFT) processor using an eight data-path pipelined approach for high rate wireless personal area network applications. A novel modified radix-25 FFT algorithm that reduces the hardware complexity is proposed. This method can reduce the number of complex multiplications and the size of the twiddle factor memory. It also uses a complex constant multiplier instead of a complex Booth multiplier. The proposed FFT processor achieves a signal-to-quantization noise ratio of 35 dB at 12 bit internal word length. The proposed processor has been designed and implemented using 90-nm CMOS technology with a supply voltage of 1.2 V. The results demonstrate that the total gate count of the proposed FFT processor is 290 K. Furthermore, the highest throughput rate is up to 2.5 GS/s at 310 MHz while requiring much less hardware complexity.

{\rm Radix}-2^{5}

A reduced-complexity low density parity check (LDPC) layered decoding architecture is proposed using an offset permutation scheme in the switch networks. This method requires only one shuffle network, rather than the two shuffle networks which are used in conventional designs. In addition, we use a block parallel decoding scheme by suitably mapping between required memory banks and processing units in order to increase the decoding throughput. The proposed architecture is realized for a 672-bit, rate-1/2 irregular LDPC code on a Xilinx Virtex-4 FPGA device. The design achieves an information throughput of 822 Mb/s at a clock speed of 335 MHz with a maximum of 8 iterations.

FFT Processor for High Rate WPAN Applications

This paper presents a high-speed Forward Error Correction (FEC) architecture based on two-parallel Reed-Solomon (RS) decoder for 10 and 40-Gb/s optical communication systems. A high-speed two-parallel RS(255, 239) decoder has been proposed and the derived structure can also be applied to implement the 10 and 40-Gb/s RS FEC architectures. The implementation results show that 16-Ch. RS FEC architecture can operate at a clock frequency of 160MHz and has a throughput of 41Gb/s for the Xilinx Virtex4 FPGA. Also, RS FEC operates at a clock frequency of 400MHz and has a throughput of 102Gb/s for 0.18-µm CMOS technology.

A Reduced-Complexity Architecture for LDPC Layered Decoding Schemes

This paper describes the use of digit-serial arithmetic for compact and efficient implementations of real-time DSP applications on field programmable gate arrays (FPGAs). As an example, the implementation of a digit-serial 5-tap FIR filter on a Xilinx XC4010 FPGA is considered. An analysis of the performance comparison of several FIR filters is described. The results show that digit-serial designs with a digit-size of 2 bits have about 17% smaller area-time product than those of a bit-serial implementations.

Two-parallel Reed-Solomon based FEC architecture for optical communications

This paper presents a novel high-speed low-complexity pipelined degree-computationless modified Euclidean (pDCME) algorithm architecture for high-speed RS decoders. The pDCME algorithm allows elimination of the degree-computation so as to reduce hardware complexity and obtain high-speed processing. A high-speed RS decoder based on the pDCME algorithm has been designed and implemented with 0.13-μm CMOS standard cell technology in a supply voltage of 1.1 V. The proposed RS decoder operates at a clock frequency of 660 MHz and has a throughput of 5.3 Gb/s. The proposed architecture requires approximately 15% fewer gate counts and a simpler control logic than architectures based on the popular modified Euclidean algorithm.