405 research outputs found
BER Analysis of OFDM Systems Impaired by Phase Noise in Frequency-Selective Rayleigh Fading Channels
[[abstract]]In this paper, we study the effect of finite-power, phase-locked-loop (PLL) based phase noise on the bit-error-rate (BER) of orthogonal frequency division multiplexing (OFDM) systems in frequency-selective Rayleigh fading channels. Based on the conditional Gaussian approximation technique, we derive the BER formulas for BPSK and 16-QAM modulated OFDM signals impaired by phase noise in frequency-selective Rayleigh fading channels. Simulation results not only validate the accuracy of our analysis but also show the dependency of BERs on the shapes of phase noise spectra.[[conferencetype]]國際[[conferencedate]]20081130~20081204[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]New Orleans, U.S.A
Exact BER Analysis of OFDM Systems Communicating over Frequency-Selective Fading Channels Subjected to Carrier Frequency Offset
Orthogonal Frequency Division Multiplexing (OFDM) has been employed in numerous wireless standards. However, the performance of OFDM systems is degraded by both the Carrier Frequency Offset (CFO) and the Phase Estimation Error (PER). Hence new exact closed-form expressions are derived for calculating the average BER of OFDM systems in the presence of both CFO and PER in the context of frequency selective Nakagami-m fading channels. Our simulation results verify the accuracy of our exact BER analysis. By contrast, the Gaussian approximation slightly over-estimates the average BER, especially when the normalized CFO is small, the number of OFDM subcarriers is low and when the fading is less severe
Performance Analysis of Coherent and Noncoherent Modulation under I/Q Imbalance
In-phase/quadrature-phase Imbalance (IQI) is considered a major
performance-limiting impairment in direct-conversion transceivers. Its effects
become even more pronounced at higher carrier frequencies such as the
millimeter-wave frequency bands being considered for 5G systems. In this paper,
we quantify the effects of IQI on the performance of different modulation
schemes under multipath fading channels. This is realized by developing a
general framework for the symbol error rate (SER) analysis of coherent phase
shift keying, noncoherent differential phase shift keying and noncoherent
frequency shift keying under IQI effects. In this context, the moment
generating function of the signal-to-interference-plus-noise-ratio is first
derived for both single-carrier and multi-carrier systems suffering from
transmitter (TX) IQI only, receiver (RX) IQI only and joint TX/RX IQI.
Capitalizing on this, we derive analytic expressions for the SER of the
different modulation schemes. These expressions are corroborated by comparisons
with corresponding results from computer simulations and they provide insights
into the dependence of IQI on the system parameters. We demonstrate that the
effects of IQI differ considerably depending on the considered system as some
cases of single-carrier transmission appear robust to IQI, whereas
multi-carrier systems experiencing IQI at the RX require compensation in order
to achieve a reliable communication link
Efficient space-frequency block coded pilot-aided channel estimation method for multiple-input-multiple-output orthogonal frequency division multiplexing systems over mobile frequency-selective fading channels
© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.An iterative pilot-aided channel estimation technique for space-frequency block coded (SFBC) multiple-input multiple-output orthogonal frequency division multiplexing systems is proposed. Traditionally, when channel estimation techniques are utilised, the SFBC information signals are decoded one block at a time. In the proposed algorithm, multiple blocks of SFBC information signals are decoded simultaneously. The proposed channel estimation method can thus significantly reduce the amount of time required to decode information signals compared to similar channel estimation methods proposed in the literature. The proposed method is based on the maximum likelihood approach that offers linearity and simplicity of implementation. An expression for the pairwise error probability (PEP) is derived based on the estimated channel. The derived PEP is then used to determine the optimal power allocation for the pilot sequence. The performance of the proposed algorithm is demonstrated in high frequency selective channels, for different number of pilot symbols, using different modulation schemes. The algorithm is also tested under different levels of Doppler shift and for different number of transmit and receive antennas. The results show that the proposed scheme minimises the error margin between slow and high speed receivers compared to similar channel estimation methods in the literature.Peer reviewe
Uplink Performance of Time-Reversal MRC in Massive MIMO Systems Subject to Phase Noise
Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an
excess of base station (BS) antennas (Massive MIMO) offer unprecedented
multiplexing gains and radiated energy efficiency. Oscillator phase noise is
introduced in the transmitter and receiver radio frequency chains and severely
degrades the performance of communication systems. We study the effect of
oscillator phase noise in frequency-selective Massive MIMO systems with
imperfect channel state information (CSI). In particular, we consider two
distinct operation modes, namely when the phase noise processes at the BS
antennas are identical (synchronous operation) and when they are independent
(non-synchronous operation). We analyze a linear and low-complexity
time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both
operation modes we derive a lower bound on the sum-capacity and we compare
their performance. Based on the derived achievable sum-rates, we show that with
the proposed receive processing an array gain is achievable. Due
to the phase noise drift the estimated effective channel becomes progressively
outdated. Therefore, phase noise effectively limits the length of the interval
used for data transmission and the number of scheduled users. The derived
achievable rates provide insights into the optimum choice of the data interval
length and the number of scheduled users.Comment: 13 pages, 6 figures, 2 tables, IEEE Transactions on Wireless
Communications (accepted
Channel Estimation for Millimeter-Wave Massive MIMO with Hybrid Precoding over Frequency-Selective Fading Channels
Channel estimation for millimeter-wave (mmWave) massive MIMO with hybrid
precoding is challenging, since the number of radio frequency (RF) chains is
usually much smaller than that of antennas. To date, several channel estimation
schemes have been proposed for mmWave massive MIMO over narrow-band channels,
while practical mmWave channels exhibit the frequency-selective fading (FSF).
To this end, this letter proposes a multi-user uplink channel estimation scheme
for mmWave massive MIMO over FSF channels. Specifically, by exploiting the
angle-domain structured sparsity of mmWave FSF channels, a distributed
compressive sensing (DCS)-based channel estimation scheme is proposed.
Moreover, by using the grid matching pursuit strategy with adaptive measurement
matrix, the proposed algorithm can solve the power leakage problem caused by
the continuous angles of arrival or departure (AoA/AoD). Simulation results
verify that the good performance of the proposed solution.Comment: 4 pages, 3 figures, accepted by IEEE Communications Letters. This
paper may be the first one that investigates the frequency selective fading
channel estimation for mmWave massive MIMO systems with hybrid precoding. Key
words: Millimeter-wave (mmWave) massive MIMO, frequency-selective fading,
channel estimation, compressive sensing, hybrid precodin
- …