SC-FDE

About: SC-FDE is a research topic. Over the lifetime, 438 publications have been published within this topic receiving 7547 citations.

Adaptive Detector for SC-FDE in Multiuser DS-UWB Systems Based on Structured Channel Estimation with Conjugate Gradient Algorithm

Abstract: In this work, we propose a conjugate gradient (CG) based structured channel estimation (SCE) scheme for single-carrier frequency domain equalization (SC-FDE) in multiuser direct-sequence ultra-wideband (DS-UWB) systems. The minimum mean square error (MMSE) linear detection strategy is used and a cyclic prefix is employed. We perform the adaptive channel estimation in the frequency domain and implement the despreading in the time domain after the FDE. In this scheme, the linear MMSE detection requires the knowledge of the number of users and the noise variance. For this purpose, we propose algorithms for estimating these parameters. A CG adaptive algorithm is then developed for the SCE scheme. With lower complexity than the recursive least squares (RLS) algorithm and better performance than the Least mean squares (LMS) algorithm, the SCE-CG achieves a better tradeoff between the complexity and the performance.

Single-Carrier Frequency-Domain Equalization (SC-FDE) subscriber equipment with automatic physical layer request retransmission mechanism

Abstract: The utility model discloses a single carrier frequency-domain equalization(SC-FDE) user facility that is provided with a physical layer resending request mechanism. The user facility is provided with a receiver which is provided with a physical receiver that is used for modulating packs. Each pack is specifically encoded/digitally modulated. The specific coding/digital modulating employs HSPA modulation solution and forward error correction(FEC) coding. A mixed ARQ combiner/decoder is coupled with the physical receiver so as to buffer, decode and detect the error of the package. If the error rate is acceptable, a confirmation emitter that is coupled with the mixed ARQ combiner/decoder confirms the pack.

A novel and robust timing synchronization method for SC-FDE 60GHz WPAN systems

Abstract: This paper addresses a training-sequence-based timing synchronization algorithm for 60GHz wireless personal area networks (WPAN) systems based on single-carrier transmission with frequency domain equalization (SC-FDE), and the training sequence adapts Frank-Zadoff preamble structure. The proposed method includes two parts. First, a coarse timing synchronization (CTS) is achieved. The start of frame can be found where the exact position is in AWGN channel and most LOS channels. Further, rather than estimate channel impulse response, we propose a fine timing synchronization (FTS) based on cross-correlation property, where we can find the first significant channel tap or the region that causes less inter-block-interference (IBI) in 60GHz NLOS channel Models(the maximum channel delay spread is larger than the length of CP). Compared with current FTS methods, our algorithm has lower complexity while better performance. The simulation results confirm that our algorithm is robust, and has excellent performance in different 60GHz channel Models.

Optimal Tx-BF for MIMO SC-FDE Systems

Abstract: Transmit beamforming (Tx-BF) for multiple-input multiple-output (MIMO) channels is an effective means to improve system performance. In frequency-selective channels, Tx-BF can be implemented in combination with single-carrier frequency-domain equalization (SC-FDE) to combat inter-symbol interference. In this paper, we consider the optimal design of the Tx-BF matrix for a MIMO SC-FDE system employing a linear minimum mean square error (MSE) receiver. We formulate the Tx-BF optimization problem as the minimization of a general function of the stream MSEs, subject to a transmit power constraint. The optimal structure of the Tx-BF matrix is obtained in closed form and an efficient algorithm is proposed for computing the optimal power allocation. Our simulation results validate the excellent performance of the proposed scheme in terms of uncoded bit-error rate and achievable bit rate.

SINR analysis of FFH/OFDM over frequency selective Rayleigh fading channel

Abstract: Fast frequency hopping/orthogonal frequency division multiplexing FFH/OFDM has been previously proposed to achieve frequency diversity over frequency selective channels. However, the performances of the FFH/OFDM scheme have been usually calculated using simulations over empirical channel models in earlier works. The main aim of this paper is to theoretically expose the diversity of the FFH/OFDM signal over statistical models, specifically Rayleigh distributed, for frequency selective fading channels. In order to achieve this aim, we first derive the decision variables and the signal-to-interference noise ratios of the FFH/OFDM signal at the output of minimum mean square error and zero forcing receivers. For various levels of quadrature amplitude modulation used in FFH/OFDM, the performances are calculated and validated via simulations. The results show that FFH/OFDM in case of zero forcing equalization does not provide any diversity gain even over a frequency selective channel. However, in case of minimum mean square error equalization, it brings significant diversity gain at high signal-to-noise ratio SNR values with the rise of number of sub-carriers. Moreover, the FFH/OFDM with four quadrature amplitude modulation scheme provides better performance than that of the conventional OFDM even at low SNR values, as well as a significant diversity gain at high SNR values. Copyright © 2016 John Wiley & Sons, Ltd.