This paper presents a high-speed hardware architecture of an improved Givens rotation-based QR decomposition, named tournament-based complex Givens rotation (T-CGR). In the proposed approach, more than one pivots are selected and zero-insertion processes of Givens-rotations are performed in parallel like tournament in order to increase the throughput. As a result, the QR decomposition performance significantly increases compared to the triangular systolic array (TSA) approach. Moreover, the circuit area was reduced due to the smaller number of flip-flops for holding the computed results during the decomposition process. The proposed QR decomposition hardware was implemented using TSMC 0.25 um technology. The experimental results show that the proposed architecture achieves 73.00% speed-up over the TACR/TSA-based architecture for the 8 × 8 matrix decomposition.

High-speed tournament givens rotation-based QR Decomposition Architecture for MIMO Receiver

This paper presents a low complexity QR decomposition (QRD) architecture for MIMO detector. In the proposed approach, various CORDIC-based QRD algorithms are efficiently combined together to reduce the computational complexity of the QRD hardware. Based on the computational complexity analysis on various QRD algorithms, a low complexity approach is selected at each stage of QRD process. The proposed QRD architecture can be applied to any arbitrary dimension of channel matrix, and the complexity reduction grows with the increasing matrix dimension. Our QR decomposition hardware was implemented using Samsung 0.13 μm technology. The numerical results show that the proposed architecture achieves 47% increase in the QAR (QRD Rate/Gate count) with 28.1% power savings over the conventional Householder CORDIC-based architecture for the 4x4 matrix decomposition.

A low-complexity composite QR decomposition architecture for MIMO detector

The adaptive relaxation algorithm is an algorithm that minimizes the residual energy and such that it is used to accelerate the convergence of the iterative algorithm. This algorithm has been proved powerful to some kinds of problems. In this paper, we show some results after we apply this algorithm to a phase retrieval problem.

Application of an Adaptive Relaxation Algorithm to a Phase Retrieval Problem

This paper presents a high-speed QR decomposition architecture for the multi-input-multi- output (MIMO) receiver based on Givens rotation. Under fast-varying channel, since the inverse matrix calculation has to be performed frequently in MIMO receiver, a high performance and low latency QR decomposition module is highly required. The proposed QR decomposition architecture is composed of Sign-Select Lookahead (SSL) coordinate rotation digital computer (CORDIC). In the SSL-CORDIC, the sign bits, which are computed ahead to select which direction to rotate, are used to select one of the last iteration results, therefore, the data dependencies on the previous iterations are efficiently removed. Our proposed QR decomposition module is implemented using TSMC 0.25 µm CMOS process. Experimental results show that the proposed QR architecture achieves 34.83% speed-up over the Compact CORDIC based architecture for the 4 × 4 matrix decomposition.

Sign-select lookahead CORDIC based high-speed QR decomposition architecture for MIMO receiver applications

Music affects sensitivity and emotion of human, emotional power of the music has been applied to various fields. Especially, to visualize as well as listen to music is able to create various atmosphere. In this paper, we proposed sensitivity control system for interaction with people to merge music and lighting. Because existing FT(Fourier Transform) has not information about the time, to analyze information of changed signal according to the time is difficult. In order to solve such a problem, we use STFT(Short Time Fourier Transform) method to analyze music signal. and also, we classified music for three genre and compared the frequency characteristics according to genre, and control the color, brightness of LED light based on the frequency components within analysis range. Unlike existing LED lighting control study using music, we had color control of emotional lighting and brightness control using variation amount of music signal in this paper. Proposed lighting control system will be able to utilize various industry fields as well as emotional lighting.

/pdf/lighting-control-using-frequency-analysis-of-music-1j0j68xby1.pdf

Lighting Control using Frequency Analysis of Music

In this paper, we propose a new gain design technique for sigma-delta A/D converters. In the proposed scheme, multiple gain set candidates showing maximum SNR at the modulator output stage are selected, and then investigated for maximum SNR in the decimation circuit output stage through CIC decimation filter simulation. It is shown that a better gain set can be obtained through SNR monitoring at the modulator output and the decimation circuit output stages.

New Modulator Gain Design Technique for Sigma-Delta A/D Converters Using CIC Decimation Filters

In this paper, a low-area FFT structure using algorithm is proposed. The large point FFT structure consists of cascade connection of the many stages. In implementation of large point FFT using algorithm, stages which number of different coefficients are only 3 appear in every 2 stages. For example, in the 4096-point FFT, the stages that number of different coefficients are 3 appear in stage 1, 3, and 5 among 6 stages. Multiplication block area of these 3 stages can be reduced using CSD(Canonic Signed Digit) and common sub-expression sharing techniques. Using the proposed structure, the 256-point FFT is implemented with the Verilog-HDL coding and synthesized by cell area in tsmc CMOS library. This result shows 23% cell area reduction compared with the conventional structure.

Low-area FFT Processor Structure using Radix-4^2 Algorithm

In this paper, an efficient butterfly structure for 8K/2K-Point Radix-4 FFT algorithm using CORDIC(coordinate rotation digital computer) is proposed. It is shown that CORDIC can be efficiently used in twiddle factor calculation of the Radix-4 FFT algorithm. The Verilog-HDL coding results for the proposed CORDIC butterfly structure show 36.9% cell area reduction comparison with those of the conventional multiplier butterfly structure. Furthermore, the 8K/2K-point Radix-4 pipeline structure using the proposed butterfly and delay commutators is compared with other conventional structures. Implementation coding results show 11.6% cell area reduction. Due to its efficient processing scheme, the proposed FFT structure can be widely used in large size of FFT like OFDM Modem.

http://www.koreascience.or.kr:80/article/JAKO200822179196342.pdf

A Low-power DIF Radix-4 FFT Processor for OFDM Systems Using CORDIC Algorithm

In this paper, a Residual Frequency Offset (RFO) synchronization scheme using a simplified Coordinate Rotation Digital Computer (CORDIC) algorithm is proposed for Orthogonal Frequency Division Multiplexing (OFDM) systems. The RFO synchronization scheme using a conventional CORDIC algorithm uses the vector-mode CORDIC for RFO estimation, and the rotation-mode CORDIC for RFO compensation. The proposed scheme also uses the vector-mode CORDIC for RFO estimation. However, for RFO compensation, the proposed scheme uses simple division hardware instead of the rotation-mode CORDIC. The implementation results show that the proposed scheme can achieve a significant reduction in hardware complexity.

A Residual Frequency Offset Synchronization Scheme Using a Simplified CORDIC Algorithm in OFDM Systems

An efficient pipeline MDC Radix-4 FFT structure is proposed in this paper. Every stages in pipeline FFT structure consists of delay' commutator and butterfly. Proposed butterflies in front and rear stages utilize CORDIC and Common Sub-expression Sharing(CSS) techniques, respectively. It is shown that proposed butterfly structure can reduce the number of adders through sharing common patterns of CSD type coefficients. The Verilog-HDL modeling and Synopsys logic synthesis results that the proposed structure show 48.2% cell area reduction in the complex multiplication part and 22.1% cell area reduction in overall 256-point FFT structure comparison with those of the conventional structures. Consequently, the proposed FFT structure can be efficiently used in various OFDM systems.

Young-Beom Jang

Papers

New Modulator Gain Design Technique for Sigma-Delta A/D Converters Using CIC Decimation Filters

Low-area FFT Processor Structure using Radix-4^2 Algorithm

A Low-power DIF Radix-4 FFT Processor for OFDM Systems Using CORDIC Algorithm

A Residual Frequency Offset Synchronization Scheme Using a Simplified CORDIC Algorithm in OFDM Systems

Low-area Pipeline FFT Structure in OFDM System Using Common Sub-expression Sharing and CORDIC