Browsing by Author "Chai, Li-Wei"

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Interpolation-Based QR Decomposition and Channel Estimation Processor for MIMO-OFDM System
(2011-05-01)
Chiu, Po-Lin
;
Huang, Lin-Zheng
;
Chai, Li-Wei
;
Huang, Yuan-Hao
;
電信工程研究所
This paper presents a modified interpolation-based QR decomposition algorithm for the grouped-ordering multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Based on the original research that integrates the calculations of the frequency-domain channel estimation and the QR decomposition for the MIMO-OFDM system, this study proposes a modified algorithm that possesses a scalable property to save the power consumption for interpolation-based QR decomposition in the variable-rank MIMO scheme. Furthermore, we also develop the general equations and a timing scheduling method for the hardware design of the proposed QR decomposition processor for the higher-dimension MIMO system. Based on the proposed algorithm, a configurable interpolation-based QR decomposition and channel estimation processor was designed and implemented using a 90-nm one-poly nine-metal CMOS technology. The processor supports 2 2, 2 4 and 4 4 QR-based MIMO detection for the 3GPP-LTE MIMO-OFDM system and achieves the throughput of 35.16 MQRD/s at its maximum clock rate 140.65 MHz.
Reduced-Complexity Interpolation-based QR Decomposition using Partial Layer Mapping
(2011)
Chai, Li-Wei
;
Chiu, Po-Lin
;
Huang, Yuan-Hao
;
電信工程研究所
;
Institute of Communications Engineering
This paper presents a double one-dimension interpolation-based QR decomposition (DOD-IQRD) algorithm and a partial layer-mapping (PLM) scheme for multiple-input multiple-output (MIMO) orthogonal-frequency-division-multiplexing (OFDM) systems. The proposed algorithm integrates the calculations of frequency-domain channel estimation and QR decomposition for MIMO-OFDM systems, and thus requires less computational complexity than traditional scheme. Besides, the proposed partial layer-mapping scheme can further reduce computational complexity with negligible performance degradation. The analysis results show that the double one-dimension interpolation-based QR decomposition algorithm reduces the complexity to 45.2% of the traditional algorithm in the 3GPP-LTE 4x4 MIMO-OFDM system. The proposed QR decomposition algorithm combined with the partial layer-mapping scheme can further save up to 70.5% computational complexity for MIMO-OFDM systems.