SC-FDE

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

Rate Optimization for Hybrid SC-FDE/OFDM Decode-and-Forward MIMO Relay Systems

Abstract: In this paper, we consider the rate-optimal transceiver design for a hybrid single-carrier frequency-domain equalization and orthogonal frequency-division multiplexing decode-and-forward (DF) multiple-input–multiple-output (MIMO) relay system. Such hybrid systems can provide a high end-to-end bit rate and a low peak-to-average power ratio at one of the transmitting nodes. Assuming minimum mean-squared-error equalization at the receiving nodes, we optimize the transmit precoding matrices for maximization of the achievable bit rate (ABR) of the system subject to a joint node transmit power constraint. We provide a unified solution for the precoding matrices, which subsumes the solutions for pure single-carrier and pure multicarrier MIMO DF relay systems as special cases. Specifically, the optimal structure of the precoding matrices is obtained by exploiting the relation between our design and conventional point-to-point MIMO transceiver designs. With the optimal precoding structure, the optimization problem reduces to a convex power allocation problem, for which an efficient closed-form solution is derived. Numerical results are provided to confirm the excellent ABR performance of the proposed relaying schemes.

Low complexity multiple user detection for SC-FDE with OQPSK signals

Abstract: It is widely accepted that SC-FDE (Single Carrier with Frequency Domain Equalization) schemes are preferable for the uplink of broadband wireless systems since these signals have lower PAPR (Peak to Average Power Ratio) than OFDM (Orthogonal Frequency Division Multiplexing) signals. However, when we want to employ power-efficient grossly nonlinear amplifiers, as in satellite communications, the SC signals must have quasi-constant envelopes which have a spectral occupation much higher than the minimum Nyquist band, resulting in low spectral efficiency. In this paper we consider a low complexity pragmatic FDMA (Frequency Division Multiple Access) system employing OQPSK (Offset Quaternary Phase Shift Keying) modulations with quasi-constant envelope that increases the overall spectral efficiency by considering total spectral overlapping of two different users. To mitigate the overall interference, we present an iterative frequency-domain receiver with parallel multiple user detection capable to cope with ISI (Inter-Symbol Interference), CCI (Co-Channel Interference) levels inherent to the spectral overlapping, and IQI (In-phase/Quadrature Interference), the interference between the in-phase (I) and quadrature (Q) components of the OQPSK signals, for severely time-dispersive channels.

Receiver design for the uplink of base station cooperation systems employing SC-FDE

Abstract: The presented paper considers the uplink transmission in base station (BS) cooperation schemes where mobile terminals (MTs) in adjacent cells share the same physical channel. We consider single-carrier with frequency-domain equalization (SC-FDE) combined with iterative frequency-domain receivers based on the iterative block decision feedback equalization (IB-DFE). We study the quantization requirements when sending the received signals, from different MTs, at different BSs to a central unit that performs the separation of different MTs using iterative frequency-domain receivers. Our performance results show that a relatively coarse quantization, with only 4 bits in the in-phase and quadrature components of the complex envelope already allows close-to-optimum macro-diversity gains, as well as an efficient separation of the transmitted signals associated with each MT.

Improved symbol timing synchronization algorithms for SC-FDE systems

Abstract: Symbol timing synchronization is a key technology for SC-FDE (Single Carrier Frequency Domain Equalization) systems. The traditional Schmidl & Cox's and Minn's algorithms have some shortcoming on the existence of timing metric plateau and redundant peaks. To overcome these shortcomings, two symbol timing synchronization algorithms based on a novel structure of training symbol are proposed for SC-FDE systems in this paper. The proposed methods can take advantage of the correlations of the four parts of the training symbol to efficiently improve the accuracy of timing synchronization and the anti-multipath capability. The simulation results confirm that the performances of the proposed algorithms are superior to Minn's algorithm in AWGN channel and 3GPP Vehicular A channel.