2,166 research outputs found
Multi-sample Receivers Increase Information Rates for Wiener Phase Noise Channels
A waveform channel is considered where the transmitted signal is corrupted by
Wiener phase noise and additive white Gaussian noise (AWGN). A discrete-time
channel model is introduced that is based on a multi-sample receiver. Tight
lower bounds on the information rates achieved by the multi-sample receiver are
computed by means of numerical simulations. The results show that oversampling
at the receiver is beneficial for both strong and weak phase noise at high
signal-to-noise ratios. The results are compared with results obtained when
using other discrete-time models.Comment: Submitted to Globecom 201
Capacity Outer Bound and Degrees of Freedom of Wiener Phase Noise Channels with Oversampling
The discrete-time Wiener phase noise channel with an integrate-and-dump
multi-sample receiver is studied.
A novel outer bound on the capacity with an average input power constraint is
derived as a function of the oversampling factor.
This outer bound yields the degrees of freedom for the scenario in which the
oversampling factor grows with the transmit power as .
The result shows, perhaps surprisingly, that the largest pre-log that can be
attained with phase modulation at high signal-to-noise ratio is at most .Comment: 5 pages, 1 figure, Submitted to Intern. Workshop Inf. Theory (ITW)
201
Phase Modulation for Discrete-time Wiener Phase Noise Channels with Oversampling at High SNR
A discrete-time Wiener phase noise channel model is introduced in which
multiple samples are available at the output for every input symbol. A lower
bound on the capacity is developed. At high signal-to-noise ratio (SNR), if the
number of samples per symbol grows with the square root of the SNR, the
capacity pre-log is at least 3/4. This is strictly greater than the capacity
pre-log of the Wiener phase noise channel with only one sample per symbol,
which is 1/2. It is shown that amplitude modulation achieves a pre-log of 1/2
while phase modulation achieves a pre-log of at least 1/4.Comment: To appear in ISIT 201
Lower Bound on the Capacity of Continuous-Time Wiener Phase Noise Channels
A continuous-time Wiener phase noise channel with an integrate-and-dump
multi-sample receiver is studied.
A lower bound to the capacity with an average input power constraint is
derived, and a high signal-to-noise ratio (SNR) analysis is performed.
The capacity pre-log depends on the oversampling factor, and amplitude and
phase modulation do not equally contribute to capacity at high SNR.Comment: Extended version of a paper submitted to ISIT 2015. 9 pages and 1
figure. arXiv admin note: text overlap with arXiv:1411.039
Analysis and optimization of pilot symbol-assisted Rake receivers for DS-CDMA systems
The effect of imperfect channel estimation (CE) on the performance of pilot-symbol-assisted modulation (PSAM) and MRC Rake reception over time- or frequency-selective fading channels with either a uniform power delay profile (UPDP) or a nonuniform power delay profile (NPDP) is investigated. For time-selective channels, a Wiener filter or linear minimum mean square error (LMMSE) filter for CE is considered, and a closed-form asymptotic expression for the mean square error (MSE) when the number of pilots used for CE approaches infinity is derived. In high signal-to-noise ratio (SNR), the MSE becomes independent of the channel Doppler spectrum. A characteristic function method is used to derive new closed-form expressions for the bit error rate (BER) of Rake receivers in UPDP and NPDP channels. The results are extended to two-dimensional (2-D) Rake receivers. The pilot-symbol spacing and pilot-to-data power ratio are optimized by minimizing the BER. For UPDP channels, elegant results are obtained in the asymptotic case. Furthermore, robust spacing design criteria are derived for the maximum Doppler frequency
Capacity bounds for MIMO microwave backhaul links affected by phase noise
We present bounds and a closed-form high-SNR expression for the capacity of
multiple-antenna systems affected by Wiener phase noise. Our results are
developed for the scenario where a single oscillator drives all the
radio-frequency circuitries at each transceiver (common oscillator setup), the
input signal is subject to a peak-power constraint, and the channel matrix is
deterministic. This scenario is relevant for line-of-sight multiple-antenna
microwave backhaul links with sufficiently small antenna spacing at the
transceivers. For the 2 by 2 multiple-antenna case, for a Wiener phase-noise
process with standard deviation equal to 6 degrees, and at the medium/high SNR
values at which microwave backhaul links operate, the upper bound reported in
the paper exhibits a 3 dB gap from a lower bound obtained using 64-QAM.
Furthermore, in this SNR regime the closed-form high-SNR expression is shown to
be accurate.Comment: 10 pages, 2 figures, to appear in IEEE Transactions on Communication
On continuous-time white phase noise channels
A continuous-time model for the additive white Gaussian noise (AWGN) channel in the presence of white (memoryless) phase noise is proposed and discussed. It is shown that for linear modulation the output of the baud-sampled filter matched to the shaping waveform represents a sufficient statistic. The analysis shows that the phase noise channel has the same information rate as an AWGN channel but with a penalty on the average signal-to-noise ratio, the amount of penalty depending on the phase noise statistic. © 2014 IEEE
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