Browsing by Author "Deng, JH"

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A low complexity group-wise PIC based mixed-mode MIMO-OFDM system
(2004)
Deng, JH
;
Lin, CY
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A mixed-mode MIMO-OFDM system with the reduced complexity group-wise parallel interference cancellation (G-PIC) algorithm is proposed. At the transmitter, the data stream is first demultiplexed into two groups of substreams, one with capacity constraint via the spatial multiplexing (SM) mode and the other with link quality constraint via the space-time block coding (STBC) mode. At the receiver, a reduced complexity GPIC is proposed to separate the transmitted streams from different antennas and is based on the following procedures: First, a group-wise MMSE detector and ordering strategy are designed for each group to provide reliable initial decisions for recursive PIC. Second, a recursive group-wise detector, which consists of a conventional PIC, subspace projector and reduced size NIL searcher, is developed. Simulation results show that the proposed reduced complexity G-PIC provides almost identical performance compared to the conventional BLAST and relatively lower computational load.
A multistage multi-carrier CDMA receiver with blind adaptive MAI suppression
(2001)
Deng, JH
;
Lin, GJ
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A multistage multicarrier CDMA (MSMC-CDMA) receiver with enhanced multiple access interference (MAI) suppression is proposed for a reverse link time-multiplexed pilot symbols assisted system over multipath channels. The design of the receiver involves the following procedure. First, a blind adaptive matched filter is attached to each finger to perform despreading and combat MAI. Second, channel estimation and a RAKE combiner gives the estimate of the signal. Finally, signal reconstruction is accomplished by exploiting the channel estimate, data decisions, and signal's signature. The reconstructed signal is then subtracted from the data sent to the next stage. With signal reconstruction and subtraction as stages proceed, the MSMC-CDMA receiver can achieve nearly the performance of the optimal maximum SINR (MSINR) receiver, as confirmed by simulations.
A multistage multi-carrier CDMA receiver with enhanced interference suppression
(2001)
Deng, JH
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A multistage multicarrier CDMA (MSMC-CDMA) receiver with enhanced multiple access interference (MAI) suppression is proposed. The design of the receiver involves the following procedure. First, a set of adaptive matched filters (MF) is constructed to collect multipath signals with different time delays. The tap weights of each MF are determined in accordance with the linearly constrained minimum variance (LCMV) criterion so that strong MAI can be effectively suppressed. Second, channel estimation and signal reconstruction are accomplished by exploiting pilot symbols,, decision-directed symbols and the signal's signature. Finally, a decision-directed RAKE receiver gives the estimate of the signal, which is then subtracted from the data sent to the next stage. The proposed receiver can be used in a reverse link system with time-multiplexed pilot symbols, and achieves nearly the performance of the optimal maximum SINR (MSINR) receiver.
A space-time multi-carrier CDMA receiver with blind adaptive MAI suppression
(2002-08-01)
Deng, JH
;
Lee, TS
;
資訊工程學系
;
電信工程研究所
;
Department of Computer Science
A space-time (ST) receiver is proposed for multiple access interference (MAI) and narrowband interference (NBI) suppression, and multipath diversity reception in wireless multi-carrier CDMA communications incorporating antenna arrays. The scheme involves three stages. First, an adaptive matched filter is attached to each finger at each antenna to combat the MAL Second, an adaptive beamformer is constructed for each finger which provides effective reception of the signal of interest (SOI) and suppression of time-varying NBI. Finally, beamformer output data from different fingers are combined to capture the signal multipath components coherently. The proposed ST receiver is shown to perform reliably under strong interference, and outperform the ST MMSE receiver with pilot symbols aided channel estimation.
An iterative maximum SINR receiver for multicarrier CDMA systems over a multipath fading channel with frequency offset
(2003-05-01)
Deng, JH
;
Lee, TS
;
電信工程研究所
;
友訊交大聯合研發中心
;
Institute of Communications Engineering
A robust iterative multicarrier code-division multiple-access (MC-CDMA) receiver with adaptive multiple-access interference (MAI) suppression is proposed for a pilot symbols assisted system over a multipath fading channel with frequency offset. The design of the receiver involves a two-stage procedure. First, an adaptive filter based on the generalized sidelobe canceller (GSC) technique is constructed at each finger to perform despreading and suppression of MAI. Second, pilot symbols assisted frequency offset estimation, channel estimation and a RAKE combining give the estimate of signal symbols. In order to enhance the convergence behavior of the GSC adaptive filters, a decisions-aided scheme is proposed, in which the signal waveform is first reconstructed and then subtracted from the input data of the adaptive filters. With signal subtraction, the proposed MC-CDMA receiver can achieve nearly the performance of the ideal maximum signal-to-interference-plus noise ratio receiver assuming perfect channel and frequency offset information. Finally, a low-complexity partially adaptive (PA) realization of the GSC adaptive filters is presented as an alternative to the conventional multiuser detectors. The new PA receiver is shown to be robust to multiuser channel estimation errors and offer nearly the same performance of the fully adaptive receiver.
Space-path spreading for high rate MIMO MC-CDMA systems with transmit diversity
(2003)
Deng, JH
;
Wu, JY
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A new MIMO transceiver is proposed for the downlink of high data rate multicarrier CDMA (MC-CDMA) systems over frequency-selective multipath channels. The design of the transceiver involves the following procedure. First, the data stream is demultiplexed into multiple substreams, which are then encoded by a set of space time block codes (STBC) for achieving spatial diversity. Second, the coded substreams are spread by a set of "space-path" spreading (SPS) codes which is designed to achieve path multiplexing by exploiting independent multipath channels and pre-suppress the multiple access interference (MAI) without the use of channel state information (CSI). These substreams; are then transmitted simultaneously from multiple antennas. At each mobile station, a simple matched filter (MF) is used to despread the received data. Linearly combining the MF outputs with the aid of CSI and employing a multi-user detection scheme can then separate the mutually interfering signals from the multiple transmit antennas and restore the diversity gain due to SPS and STBC. An increased spectral efficiency and diversity gain can thus be achieved at the same time. Simulation results confirm that the proposed transceiver offers better performance than the conventional BLAST transceiver, and achieves nearly the performance of STBC and space-time spreading BLAST transceiver.