Showing papers on "SC-FDE published in 2018"
TL;DR: The proposed techniques are particularly high for highly unbalanced MIMO systems, such as in the uplink of Base Station (BS) cooperation systems that aim for Single-Frequency Network (SFN) operation or massive MIMo systems with much more antennas at the receiver side.
Abstract: This paper considers a Multiple-Input Multiple-Output (MIMO) system with P transmitting and R receiving antennas and different overall noise characteristics on the different receiver antennas (e.g., due to nonlinear effects at the receiver side). Each communication link employs a Single-Carrier with Frequency-Domain Equalization (SC-FDE) modulation scheme, and the receiver is based on robust iterative frequency-domain multi-user detectors based on the Iterative Block Decision Feedback Equalization (IB-DFE) concept. We present low complexity efficient receivers that can employ low resolution Analog-to-Digital Converters (ADCs) and require the inversion of matrices with reduced dimension when the number of receive antennas is larger than the number of independent data streams. The advantages of the proposed techniques are particularly high for highly unbalanced MIMO systems, such as in the uplink of Base Station (BS) cooperation systems that aim for Single-Frequency Network (SFN) operation or massive MIMO systems with much more antennas at the receiver side.
8 citations
TL;DR: This paper analyzes the achievable rate of the single-carrier system with a frequency-domain equalizer (SC-FDE) under the receiver in-phase/quadrature phase (I/Q) imbalance in the radio frequency front-end and shows that depending on the value of I/Q imbalance parameters, the achievable rates approaches a saturation level.
Abstract: This paper analyzes the achievable rate of the single-carrier system with a frequency-domain equalizer (SC-FDE) under the receiver in-phase/quadrature phase (I/Q) imbalance in the radio frequency front-end. We consider linear schemes based on the minimum mean square error (MMSE), zero-forcing equalization, and a matched filter. We derive the achievable rate of the SC-FDE system hit by the I/Q imbalance for the mentioned scenarios. We show that depending on the value of I/Q imbalance parameters, the achievable rate of the system approaches a saturation level. To examine the validity of our analysis, we compare it with the simulation results and exhibit their consistency. We also consider nonlinear schemes such as an iterative block decision feedback equalizer (IB-DFE), which is an iterative scheme. We obtain the mutual information achieved by the IB-DFE in the high-signal-to-noise-ratio regime and after enough number of iterations.
6 citations
13 Jul 2018
TL;DR: In this paper, an improved MMSE-RISIC equalization algorithm is presented and will be extended to the unique word(UW) based system of space-time block coded-single carrier frequency domain equalization(STBC-SC-FDE).
Abstract: The minimum mean square error-residual inter-symbol interference cancellation(MMSE-RISIC) equalization algorithm for single carrier frequency domain equalization(SC-FDE) has estimated and removed the residual inter-symbol interference(RISI) of the minimum mean square error(MMSE) equalization, but the noise interference is still present in the decision data, what’s more, the estimation deviation of RISI will bring additional disturbances, which reduced the accuracy of equalization. So an improved MMSE-RISIC equalization algorithm is presented and will be extended to the unique word(UW) based system of space-time block coded-single carrier frequency domain equalization(STBC-SC-FDE). This algorithm utilizes the correlation between the estimated noise in UW and the estimated noise in date, the noise in data can be predicted by the estimated noise in UW and will be removed before data decision, the estimation accuracy of RISI will also be improved. Simulation results have confirmed the significant performance gain the improved MMSE-RISIC equalization could achieve compared with the MMSE-RISIC equalization.
5 citations
TL;DR: This paper focuses on the equalization applied in massive MIMO schemes, more specifically in two new low complexity receivers based on an iterative block decision feedback equalizer (IB-DFE) that avoid matrix inversion operation by replacing in the equalizer the feedforward part by an equal gain combiner or a maximum ratio combiner module.
Abstract: Massive multiple-input and multiple-output (MIMO) schemes involving several tens or even hundreds of antenna elements are pointed as one of the key technologies for 5G systems. However the huge capacity gains attainable by these schemes, are only possible with receivers able to cope with the frequency selective fading that may affect the signals. These systems can be combined with single-carrier with frequency domain equalization (SC-FDE) schemes to improve the power efficiency in uplink due to the low envelope fluctuations. However, when more antennas are involved in the communication link, channel matrix size grows and the complexity involved in equalization process can be an obstacle to power consumption and low latency. In this paper we will focus on the equalization applied in massive MIMO schemes, more specifically in two new low complexity receivers based on an iterative block decision feedback equalizer (IB-DFE) that avoid matrix inversion operation by replacing in the equalizer the feedforward part by an equal gain combiner (EGC) or a maximum ratio combiner (MRC) module.
5 citations
01 Jan 2018
TL;DR: This paper first obtained realistic infrared MIMO channel impulse responses including low-pass filter effect of infrared light-emitting-diodes, and investigates the performance of bit-error-rate and peak to average power ratio (PAPR) with respect to different modulation orders using spatial multiplexing.
Abstract: In this paper, we propose a multiple-input multiple-output (MIMO) uplink transmission scheme for optical wireless communication applications. The transmission is based on optical single-carrier frequency domain equalization (SC-FDE) due to its low complexity where the signal is transmitted over infrared communication channels. Based on non-sequential ray tracing, we first obtained realistic infrared MIMO channel impulse responses including low-pass filter effect of infrared light-emitting-diodes. We then investigate the performance of bit-error-rate (BER) and peak to average power ratio (PAPR) with respect to different modulation orders using spatial multiplexing.
4 citations
01 Nov 2018
TL;DR: A new widely linear iterative equalizer for Single Carrier systems with Frequency Domain Equalization (SC-FDE) that takes into account up to K independent interferers in the symbol estimation process is introduced.
Abstract: In this paper, we introduce a new widely linear iterative equalizer for Single Carrier systems with Frequency Domain Equalization (SC-FDE) that takes into account up to K independent interferers in the symbol estimation process. In the proposed equalizer design method, we assume that there is ideal feedback after the first equalizer iteration in order to reduce the complexity. It was seen that the proposed iterative structure has a better error performance when compared to the non-iterative version regardless of the number of interferers and the interference power.
3 citations
Patent•
02 Oct 2018
TL;DR: In this paper, a receiving end IQ imbalance estimation and compensation method and device for an SC-FDE system is presented, and the stream analysis of modulated data is performed at the transmitting end.
Abstract: The invention discloses a receiving end IQ imbalance estimation and compensation method and device for an SC-FDE system, and the stream analysis of modulated data is performed at a transmitting end. CP is added to a data block, and the data block is received by a receiving end through a wireless channel and noise interference. The received signal introduces IQ imbalance because of the hardware damage of a radio frequency end. The method provided by the invention comprises the steps: carrying out the FFT of time domain data to a frequency domain after the CP of data is removed at the receivingend; estimating the channel information in advance through pilot frequency data, and obtaining an IQ imbalance parameter estimated value; carrying out the mirroring of the received signal afterwards,carrying out the merging, and estimating the frequency domain data of an original signal through LS; and finally restoring the original data through IFFT and demodulation. According to the method provided by the invention, the pilot frequency data is used in the frequency domain for the separated estimation of the IQ imbalance parameter and channel in advance, and then a simple LS method is used for compensating for the IQ imbalance and channel interference. Moreover, the method can be suitable for SISO and MIMO systems.
2 citations
12 Oct 2018
TL;DR: This paper considers the use of massive multiple-input, multiple-output (MIMO) combined with single-carrier with frequency-domain equalization (SC-FDE) modulations for the uplink, where phase noise occurs both at the receiver and the transmitter.
Abstract: In this paper we consider the use of massive multiple-input, multiple-output (MIMO) combined with single-carrier with frequency-domain equalization (SC-FDE) modulations for the uplink, where phase noise occurs both at the receiver and the transmitter. To cope with the channel and the phase noise effects, we propose a receiver structure for joint equalization and phase noise estimation using low-complexity iterative frequency-domain equalization based on the equal gain combining (EGC) concept for the channel equalization allied to a particle filter for the phase noise estimation procedure. Since the equalization step decouples the data streams, the complexity of the phase noise estimation step grows linearly with the number of transmit antennas. In fact, phase noise estimation occurs concurrently for each receive antenna phase noise process. Assuming small phase noise levels at the receiver (i.e., the base station) while letting the phase noise levels take larger values at the transmitter the proposed scheme displays excellent performance.
2 citations
26 Jun 2018
TL;DR: An alternative waveform called Fourier-based adaptive waveform (FAW) is proposed, which adapts the time-frequency tiling of the modulated signal to the frequency fading properties of the environment and achieves a good trade-off between SC-FDE and OFDM.
Abstract: The single carrier-frequency domain equalization (SC-FDE) scheme and the orthogonal frequency division multiplexing (OFDM) system have complementary performance benefits that make it hard to choose one or the other. This paper proposes an alternative waveform called Fourier-based adaptive waveform (FAW), which adapts the time-frequency tiling of the modulated signal to the frequency fading properties of the environment. A performance comparison based on peak-to-average power ratio and bit error rate shows that the proposed scheme achieves a good trade-off between SC-FDE and OFDM.
2 citations
TL;DR: A signal-to-noise ratio analysis and estimation algorithm for efficient phase noise mitigation that can be practically applied to single-carrier frequency-domain-equalisation (SC-FDE) systems that operate in millimetre-wave bands is demonstrated.
Abstract: This study demonstrates a signal-to-noise ratio (SNR) analysis and estimation algorithm for efficient phase noise mitigation that can be practically applied to single-carrier frequency-domain-equalisation (SC-FDE) systems that operate in millimetre-wave bands. First, the effect of phase noise in SC-FDE systems is investigated on each of the packet reception processes, namely, channel estimation, SNR estimation, and data-field reception. According to the analysis, an SNR estimation algorithm is proposed. The performance of minimum-mean-square-error equalisation and conventional phase noise mitigation algorithm can be enhanced using the proposed SNR estimation. The effectiveness of the proposed analysis and SNR estimation algorithm is verified through the link-level simulation. Compared with the conventional SNR estimation and the iterative phase noise mitigation algorithms, the proposed algorithm provides a lower packet-error rate without any iterative decoding process.
2 citations
03 Jun 2018
TL;DR: This paper presents low-complexity turbo multi-user receivers based on the maximum ratio combining (MRC) and equal gain combining (EGC) techniques, implemented in the frequency-domain and allow excellent performances, even for moderate numbers of antennas.
Abstract: This paper considers massive multiple-input, multiple output (MIMO) schemes for single-carrier with frequency-domain equalization (SC-FDE) modulations. We present low-complexity turbo multi-user receivers based on the maximum ratio combining (MRC) and equal gain combining (EGC) techniques. Our receivers are implemented in the frequency-domain and allow excellent performances, even for moderate numbers of antennas.
TL;DR: This paper compare the different of single carrier frequency domain equalization (SCFDE) and orthogonal frequency division multiplexing (OFDM), list the disadvantage of the OFDM algorithm and the advantage of SC-FDE system and the frequencydomain equalization algorithm.
Abstract: This paper compare the different of single carrier frequency domain equalization (SCFDE) and orthogonal frequency division multiplexing (OFDM), list the disadvantage of the OFDM algorithm and the advantage of SC-FDE system and the frequency domain equalization algorithm. Perform the performance of SC-FDE under the different equalization algorithms is simulated, the comparison of two frequency equalization algorithm was emulate and there is a well method for the single carrier frequency domain equalization.
Patent•
21 Aug 2018
TL;DR: In this article, the authors proposed a channel equalization method of an SC-FDE system under a wireless time-varying channel, which comprises the steps of 1, according to a data frame structure of a short wave unified US Military standard MIL_STD_188_110C based on an SCbased FDE system, at sending end, inserting a certain length of a training sequence (unique word UW) after the unknown data; 2, at receiving end, properly segmenting an FFT block on a time domain; 3, performing coarse equalization judgment on each
Abstract: The invention relates to a channel equalization method of an SC-FDE system under a wireless time-varying channel. The method comprises the steps of 1, according to a data frame structure of a short wave unified US Military standard MIL_STD_188_110C based on an SC-FDE system, at a sending end, inserting a certain length of a training sequence (unique word UW) after the unknown data; 2, at a receiving end, properly segmenting an FFT block on a time domain; 3, performing coarse equalization judgment on each data segment by using an MMSE equalization method; and 4, introducing a time domain exhaustive search method with low complexity to perform fine equalization judgment on a coarse equalization judgment result. Compared with traditional methods, the method provided by the invention is greatly improved in equalization performance. When a signal to noise ratio is 24dB, compared with the traditional methods, the error code rate of the method provided by the invention is reduced by about 1.5orders of magnitudes. Therefore, according to the method provided by the invention, the channel equalization performance of the SC-FDE system under the wireless time-varying channel is greatly improved.
01 Jan 2018
TL;DR: A single-carrier scheme with frequency domain equalization (SC-FDE) and a multiple-input multiple-output (MIMO) scheme are proposed and their basic performance in several scenarios with computer simulations are evaluated.
Abstract: We previously developed a high-definition (HD) wireless camera using millimeter waves with the orthogonal frequency division multiplexing (OFDM) scheme. Now, we are developing an 8K wireless camera that can achieve larger transmission capacity with a smaller transmitter. Considering this, we study a single-carrier scheme with frequency domain equalization (SC-FDE) and a multiple-input multiple-output (MIMO) scheme. The SC-FDE could achieve a smaller peak-to-average power ratio, resulting in a smaller power amplifier. In this paper, we propose two structures of 2×2MIMO SC-FDE and evaluate their basic performance in several scenarios with computer simulations.
01 Apr 2018
TL;DR: A breakthrough in key technologies has been achieved in the OFDM and SC-FDE compatible design of communication systems, and the key technologies of synchronization, code length and equalization need to be solved in compatible multi-carrier design.
Abstract: Based on the application requirements of tactical communications, this paper proposes a compatible design of OFDM and SC-FDE to the communication system, and demonstrates and simulates the key technologies of synchronization, code length and equalization that need to be solved in compatible multi-carrier design. In addition, a breakthrough in key technologies has been achieved in the OFDM and SC-FDE compatible design of communication systems.
01 May 2018
TL;DR: Simulation results confirm that proposed algorithm has lower steady-state mean-square error and approximately 8dB improvement in bit error rate is observed in high Doppler shifts, compared to recently proposed adaptive frequency domain decision feedback equalizer.
Abstract: In this paper, we introduce a novel adaptive frequency-domain equalizer structure for single-carrier frequency domain equalization communications. The introduced equalizer is developed by inspiring from time domain affine projection algorithm to be used in frequency domain. Simulation results confirm that proposed algorithm has lower steady-state mean-square error and approximately 8dB improvement in bit error rate is observed in high Doppler shifts, compared to recently proposed adaptive frequency domain decision feedback equalizer. Proposed algorithm also enhances the spectral efficiency by allowing longer data block usage without reducing system performance.
01 Mar 2018
TL;DR: This paper investigates the method to combat the induced ISIs together with one equalizer at the receiver and demonstrates that acceptable BER system performance can be achieved with the proposed transceiver.
Abstract: When the Faster-than-Nyquis (FTN) signal transmits in the Single Carrier Frequency-Domain Equalization (SC-FDE) system over the multipath frequency selective channel, the Inter-Symbol Interferences (ISIs) will be induced by both FTN signaling and multipath channel. In this paper, we investigate the method to combat the induced ISIs together with one equalizer at the receiver. The simulation results demonstrate that acceptable BER system performance can be achieved with our proposed transceiver.
19 Jul 2018
TL;DR: Simulation results show that the performance of the proposed simplified design of the Iterative Block Decision Feedback Equalization is similar to the traditional iterative IBDFE under frequency selective fading channels, but it imposes a lower complexity than the conventional IBDFe.
Abstract: The Single Carrier Frequency Domain Equalization (SC-FDE) system can effectively work in frequency selective fading channels. The Iterative Block Decision Feedback Equalization (IBDFE) is efficient nonlinear equalization in SC-FDE systems. However, the computational complexity is high and the complexity is proportional to the number of iterations. In this paper, a low-complexity IB-DFE is proposed. The transmitted symbols go through a linear equalizer based on the minimum-mean-square-error (MMSE) criterion and the estimated symbols is as the output of the conventional feedback equalizer. The feedforward equalizer structure remains the same. Compared with the conventional IBDFE, the iteration is cancelled and the implementation complexity is reduced. Simulation results show that the performance of the proposed simplified design is similar to the traditional iterative IBDFE under frequency selective fading channels, but it imposes a lower complexity than the conventional IBDFE.
01 Sep 2018
01 Aug 2018
TL;DR: This work presents the analytical performance evaluation of nonlinear massive MIMO systems based on SC-FDE systems employing low-complexity, iterative FDE receivers1.
Abstract: Single-carrier with frequency-domain equalization (SC-FDE) modulations are a natural choice for the uplink of massive multiple intput, multiple output (MIMO) systems, due to the low peak-to-average power ratio (PAPR) of their signals. However, equalization techniques should avoid matrix inversions. On the other hand, energy-efficient analog-to-digital converters (ADCs) should be used in each receive branch to reduce the power consumption and the implementation complexity, which might lead to strong nonlinear distortion effects. In this work, we present the analytical performance evaluation of nonlinear massive MIMO systems based on SC-FDE systems employing low-complexity, iterative FDE receivers1.