SC-FDE

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

On OFDM and SC-FDE Transmissions in Millimeter Wave Channels with Beamforming

Abstract: The air interface for millimeter wave (mmWave) communications must be designed by properly taking into account the specific characteristics of the wireless channel at higher frequencies. In this work, we start by considering a channel model recently proposed in the literature for mmWave communications in outdoor urban scenarios. First, on top of this channel model we implement a sectorized beamforming model necessary to compensate the large path-loss at mmWave range and study how channel statistics, namely, delay spread and angle spread, are influenced by employing different beamwidths. Subsequently, adopting this beamforming model in the mmWave channel, orthogonal frequency division multiplexing (OFDM) and single carrier frequency domain equalization (SC-FDE) systems are compared. Extensive link level simulations are performed by considering different beamwidths, line-of-sight (LOS) coverage and channel coding. Numerical results show that SC-FDE using minimum mean square error (MMSE) equalization performs close to OFDM in coded systems. However, SC-FDE might be beneficial in practice due to much lower peak to average power ratio (PAPR) than OFDM.

Performance of physical layer network coding in a frequency-selective fading channel

Abstract: Wireless communications are characterized by a multipath propagation that is suitable for application of network coding (NC) to improve the network performance. In particular, a physical layer network coding (PNC) is a promising technique to further improve network capacity for bi-directional information exchange between pairs of end users assisted by a relay terminal. In this paper, we present the performance of bi-directional transmission with PNC in a multipath channel. We introduce the use of frequency domain equalization (FDE) with orthogonal frequency division multiplexing (OFDM) and single carrier (SC) transmission to cope with the channel distortion. The equalization weights based on minimum mean square error (MMSE) criteria required for SC-FDE signaling are derived.

MIMO extensions for SC/FDE systems

Abstract: Several efforts are currently underway in investigating multiple-input multiple-output (MIMO) communication systems MIMO technology promises high data rate wireless communications and/or the potentiality of exploiting transmit and receive diversity schemes For WLAN (wireless local area networks) scenarios most investigations focus on OFDM (orthogonal frequency division multiplexing) transmission In this paper we discuss multiple antenna diversity and spatial multiplexing schemes for SC/FDE (single carrier transmission with frequency domain equalization), a single carrier technology closely related to OFDM due to its frequency domain signal processing characteristics Equalizer structures are derived and analyzed, and their performance is demonstrated using BER-simulations

Widely linear MMSE precoding and equalization techniques for SC-FDE systems

Abstract: Single-carrier systems using frequency-domain equalization (SC-FDE) systems were proposed to overcome the low robustness to carrier frequency offset (CFO) and high peak-to-average-power ratio (PAPR) inherent to regular orthogonal frequency-division multiplexing (OFDM) systems. Usually, linear minimum mean square error (MMSE) equalization is used to compensate the channel effect, since maximum likelihood (ML) detection is computationally impractical. However, if the transmitted signal comes from an improper constellation, widely linear processing can be used to take advantage of all the available second-order statistics from this transmitted signal, obtaining this way a performance gain when compared to the strictly linear case. In this paper, a SC-FDE system employing widely linear MMSE equalization is proposed in its regular and decision-feedback (DFE) versions. A SC-FDE system employing widely linear MMSE Tomlinson-Harashima precoding (THP) and equalization is also proposed. With Tomlinson-Harashima precoding, the error propagation problem observed in systems using a decision-feedback equalizer vanishes, because the feedback processing is done at the transmitter. Simulation results show that together with the error performance gain, these systems have lower sensibility to the feedback filter length in systems using decision-feedback equalizers. In Tomlinson-Harashima precoded systems, the performance gain is observed even with channel estimation/channel state information errors.

A time-division multiple-access SC-FDE system with IBI suppression for UWB communications

Abstract: We propose a time-division multiple-access (TDMA) scheme for the binary phase-shift keying (BPSK) modulated single carrier block transmission with frequency domain equalization (SC-FDE) over ultra-wideband (UWB) channels. The transmitter and receiver matrices for the proposed TDMA SC-FDE system are derived to achieve the multiple-access interference (MAI) free and interblock-interference (IBI) free transmission without the insertion of cyclic prefix (CP) between blocks, avoiding long CP and large fast Fourier transform (FFT) size in high-speed UWB communications. The performance of the proposed TDMA SC-FDE system over UWB channels is investigated and compared with that of the block spread code-division multiple-access (CDMA) scheme. The impact of oversampling diversity and imperfect channel estimation on the performance of the proposed system are also investigated. Results show that the proposed TDMA scheme can effectively eliminate the error floor in CDMA due to insufficient CP, and it is more efficient to accommodate larger number of users than CDMA in high data rate transmission.