6 research outputs found
Analysis and Design of Line of Sight MIMO transmission systems
A cost-effective solution to the problem of guaranteeing backhaul connectivity in mobile cellular networks is the use of point-to-point microwave links in the Q-Band and E-Band. The always increasing rate in mobile data traffic makes these microwave radio links a potential bottleneck in the deployment of high-throughput cellular networks.
A fundamental way to characterize the impact of phase noise on the throughput of these systems is to study their Shannon capacity. Unfortunately, the capacity of the phase-noise channel is not known in closed-form, even for simple channel models.
The effect of phase noise in telecommunication systems is more evident in presence of multiple antennas at transmitter and receiver because of the overlapping of phase noise contribution in receivers.
We propose a simulated-based tool to compute a lower bound to channel capacity for SISO and MIMO systems in presence of phase noise with one oscillator shared among the antennas per side and we give a non asymptotic expression of an upper bound to capacity always for SISO and MIMO channels. Finally we present a low complex phase detector based on combination of Phase Locked Loop (PLL) exploiting the decisions made by a turbo decoder.
The aim of this work is showing a way to bound the channel capacity for single antenna and multiple antennas channels impaired by phase noise generated by instabilities in oscillators driving all the transceivers, and compare the performance of the proposed phase detector to those theoretical limits
EM-Based Estimation and Compensation of Phase Noise in Massive-MIMO Uplink Communications
Phase noise (PN) is a major disturbance in MIMO systems, where the
contribution of different oscillators at the transmitter and the receiver side
may degrade the overall performance and offset the gains offered by MIMO
techniques. This is even more crucial in the case of massive MIMO, since the
number of PN sources may increase considerably. In this work, we propose an
iterative receiver based on the application of the expectation-maximization
algorithm. We consider a massive MIMO framework with a general association of
oscillators to antennas, and include other channel disturbances like imperfect
channel state information and Rician block fading. At each receiver iteration,
given the information on the transmitted symbols, steepest descent is used to
estimate the PN samples, with an optimized adaptive step size and a
threshold-based stopping rule. The results obtained for several test cases show
how the bit error rate and mean square error can benefit from the proposed
phase-detection algorithm, even to the point of reaching the same performance
as in the case where no PN is present{\color{black}, offering better results
than a state-of-the-art alternative}. Further analysis of the results allow to
draw some useful trade-offs respecting final performance and consumption of
resources.Comment: Submitted to IEEE Transactions on Communication
Cramer-Rao bounds for MIMO LOS systems affected by distributed Wiener phase noise in the large-blocklength regime
In the recent years, the ever increasing request for fast wireless communications has urged to design systems with high-throughput line-of-sight (LOS) backhaul links. To obtain the desired efficiencies, two main engineering solutions have been resorted to: multiantenna (MIMO) links and high-efficiency modulations. In comparison with single-antenna (SISO) links, MIMO LOS systems offer a relevant throughput increase but, at the same time, are more sensitive to phase noise, especially when design considerations impose to have different oscillators feeding each antenna at both side
Radio Communications
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