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In this work we investigate the effectiveness of continuous-variable (CV) entangled states, transferred through high-loss atmospheric channels, as a means of viable quantum key distribution (QKD) between terrestrial stations and low-Earth orbit (LEO) satellites. In particular, we investigate the role played by the Gaussian CV states as compared to non-Gaussian states. We find that beam-wandering induced...
The newly proposed sparse-code multiple-access (SCMA) has been shown to approach the single-user performance even the overload reaches 150% when message passing algorithm (MPA) detection is applied. Obviously, combined with multiple-input multiple-output (MIMO) techniques, the spectrum efficiency of SCMA system can be further improved. While maximum likelihood (ML) detection is optimal for MIMOSCMA,...
In this paper, a cooperative diffusion-based molecular communication system is considered where distributed receivers collaboratively determine a transmitter's signal. In this system, the receivers first make local hard decisions about the current transmitted bit and then report these decisions to a fusion center (FC). The FC combines the local hard decisions to make a global decision using an N-out-of-K...
In wideband spectrum sensing, an unlicensed user determines which portions of a given band have been left idle by the licensed users. A historical deficiency of wideband spectrum sensing, the inability to detect signals with low duty cycle, was addressed in a recent paper, where wideband temporal spectrum sensing was introduced. We propose an algorithm for reliable detection of low duty cycle signals...
We consider extensions of orthogonal matching pursuit (OMP) and oblique matching pursuit (ObMP) detectors for generalized space shift keying (GSSK). In particular, the maximum a posteriori (MAP) principle is incorporated with the OMP/ObMP so that the posteriori ratio can be maximized iteratively. Due to the fact that the posteriori ratio cannot be evaluated at the receiver unless the activated transmit...
Over the past few years, free-space optical (FSO) communication has gained significant attention. In fact, FSO can provide cost-effective and unlicensed links, with high-bandwidth capacity and low error rate, making it an exciting alternative to traditional wireless radio-frequency communication systems. However, the system performance is affected not only by the presence of atmospheric turbulences,...
This paper presents an analytical comparison of active and passive receiver models in diffusive molecular communication. In the active model, molecules are absorbed when they collide with the receiver surface. In the passive model, the receiver is a virtual boundary that does not affect molecule behavior. Two approaches are presented to derive transforms between the receiver signals. As an example,...
Correlation-based algorithms are low-complexity spectrum sensing methods requiring little knowledge on primary signals or noise signals. However, their detection performance severely degrades in the low signal-to-noise ratio (SNR) regime with low signal correlation, which happens to be quite common in practice. In this paper, a weighted correlation- based spectrum sensing scheme and its simplified...
Introducing random interruptions in the cooperation of the sensing nodes with the fusion center is a new approach to increase the efficiency of the centralized cooperative spectrum sensing in cognitive radio (CR) networks. In this paper, we extend this approach to the multiband cooperative spectrum sensing. Specifically, first, we formally show how to incorporate the random interruptions in a multiband...
In this paper, the information rate of single photon avalanche diode (SPAD) receivers with active quenching circuits for optical communication systems is studied. The SPAD receiver is modeled as a discrete memoryless channel (DMC), and the information transfer rate is studied using an information theoretic approach. To assess the input-output information transfer rate of the SPAD optical receiver,...
This paper considers a low-complexity Gaussian Message Passing Iterative Detection (GMPID) algorithm for Multiple-Input Multiple-Output systems with Non-Orthogonal Multiple Access (MIMO-NOMA), in which a base station with antennas serves sources simultaneously. Both and are very large numbers and we consider the cases that $N_u>N_r$. The GMPID is based on a fully connected...
This work studies communication over diffusion- based molecular timing (DBMT) channels. The transmitter {\em simultaneously} releases {\em multiple} small information particles, where the information is encoded in the time of release. The receiver decodes the transmitted information based on the random time of arrival of the information particles, which is represented as an additive noise channel...
Ambient backscatter communications (AmBC) enables radio-frequency (RF) powered devices (e.g., tags, sensors) to modulate their information bits over ambient RF carriers in an over-the-air manner. This system, called ``modulation in the air'', thus has emerged as a promising technology for green communications and future Internet-of-Things. This paper studies the AmBC system over ambient orthogonal...
The maximal ratio combining (MRC) receiver has excellent performance in the uplink of massive multiple-input-multiple-output (MIMO) systems under favorable propagation, but the performance degrades very much in a harsh channel because of interference. Theoretical analysis showing this phenomenon is given for a particular class of fading channel. A novel receiver, exploiting preemphasis/deemphasis...
Compared with the conventional amplitude phase modulation (APM), spatial modulation (SM) is a low- complexity, yet energy-efficient transmission technique, whereby transmit antenna (TA) indices are utilized to convey the information. However, the number of the required TAs grows exponentially with the number of transmitted bits, which leads to unacceptable pilot overhead for channel estimation in...
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