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It is well known that feedback does not increase the capacity of the AWGN channel. Schalkwijk and Kailath presented a feedback scheme that dramatically improves the error probability for finite block lengths. Unfortunately, the Schalkwijk-Kailath scheme requires perfect feedback, which is often not feasible. We study the performance of linear transmission schemes for AWGN channels with separate quantization...
With the increase of physical antenna and subcarrier numbers in MIMO-OFDM systems, the signal precoding complexity overburden and channel side information feedback amount would become enormous and intolerable. To solve this problem, previous works mainly focused on fixed subcarrier grouping size and MIMO precoded signals in the same group. It could reduce the system overburden, but such a process...
From the perspective of information flow, we first investigate the relationship between average channel capacity and average service over an Additive White Gaussian Noise (AWGN) channel. Based on the analysis, we then derive the base station arrangement strategy for the case with both large-scale fading and small-scale fading assumption. Besides, analytic comparisons of those strategies to that only...
This paper presents the performance analysis of adaptive modulation with single-cell multiuser scheduling over independent non-identically distributed (i.n.i.d.) α-μ fading channels. Average channel capacity, spectral efficiency, and bit error rate (BER) for constant-power variable-rate, and variable-power variable-rate schemes considering M-ary quadrature amplitude modulation (M-QAM) are obtained...
Channel capacity has been greatest challenge for the researchers in the field of wireless communication. Capacity analysis and its improvement have been proposed under various scenarios. However, most of them are based on conventional PDF based techniques, some times which render very complex analysis. Analysis becomes more difficult when diversity combining is used for performance improvement. Keeping...
This paper provides an upper-bound for the capacity of the underwater acoustic (UWA) channel with dominant noise sources and generalized fading environments. Previous works have shown that UWA channel noise statistics are not necessary Gaussian, especially in a shallow water environment which is dominated by impulsive noise sources. In this case, noise is best represented by the Generalized Gaussian...
New reliable and accurate capacity bounds for Poisson channel modeled optical communication system are derived under peak-power and average-power constraints. The bounds are based on two entropy inequalities of Poisson random variables. Simulation results show that the proposed bounds are much tighter than previous ones, especially at lower signal-to-noise (SNR) region, where most wireless optical...
The article considers the Wi-Fi MIMO system with dual polarization antennas. The cross-polarization decoupling is the important antennas features. It has been shown that the polarization decoupling is limiting capacity. Therefore, necessary to the accounting and possible compensation undesirable influence the cross-polarization decoupling.
In this paper, off-body channel measurements are proposed using miniaturized chip antennas (dimension: 7 × 2 × 1.20 mm3) under pattern diversity configuration at 2.2–2.3 GHz. The measurements were carried out in a multipath indoor laboratory environment using two sensors as transmitter and receiver deployed on-body and free-space, respectively where each sensor comprises two miniature chip antennas...
The design and optimization of low coding-rate channel codes is a hot topic for frequency-hopping spread-spectrum (FH-SS) transmission systems over harsh wireless channels. In this paper, we use extrinsic mutual information transfer (EXIT) chart to optimize a class of generalized low-density parity-check (GLDPC) codes over partial-band jamming (PBJ) transmission environment. With the proposed method,...
Cross-VM covert channels leverage physical resources shared between co-resident virtual machines, like CPU cache, memory bus, and disk bus, to leak information. The capacity of cross-VM covert channels varies on different cloud platforms. Thus, it is hard for cloud service providers to estimate the risk of information leakage caused by cross-VM covert channels on their own platforms. In this paper,...
This paper evaluates the performance of indoor cognitive networks in terms of the throughput and the positioning, according to the spectrum sensing time. A better sensing quality can be obtained by using a longer sensing time. The better sensing quality of a secondary user (SU), the more accurate information about a primary user (PU) positioning. However, there exists a tradeoff between the sensing...
A unified capacity analysis under weak and composite turbulences of a free-space optical (FSO) link that accounts for pointing errors and both types of detection techniques (i.e. intensity modulation/direct detection as well as heterodyne detection) is addressed in this work. More specifically, a unified exact closed-form expression for the moments of the end-to-end signal-to-noise ratio (SNR) of...
This paper introduces cognitive amplify-and-forward (AF) relay networks employing the low complexity switch-andexamine diversity combining (SEC) relaying scheme. This scheme requires low amount of channel estimations compared to the opportunistic relaying and it is based on the SEC diversity combining technique in which a relay out of multiple relays is selected to forward the source message to destination...
We investigated the use of per-channel rate-adaptive FEC for superchannels, in the presence of fiber nonlinearity, inter-channel interference, and power variations. We found 3∼4% peak capacity and ∼ 0.3dB nonlinear power threshold increase in most cases compared to the conventional method.
In this paper, we analyze a subcarrier intensity modulation (SIM) based relayed free space optical (FSO) system assuming independent but not necessarily identically distributed (i.n.i.d) Gamma-Gamma turbulence channels. System employs a channel-state-information-assisted (CSI-assisted) amplify and forward (AF) relay. We derive the moment generating function (MGF) of the end-to-end signal to noise...
The Long Term Evolution-Advanced (LTE-A) networks are being developed to provide mobile broadband services for the fourth generation (4G) cellular wireless systems. Device to-Device (D2D) communications is a promising technique to provide wireless peer-to-peer communication services and enhance resource utilization, as well as spectrum efficiency. In this paper, a centralized resource allocation scheme...
In this paper, the user cooperation behaviors under eavesdropping attack are analyzed through game theory. Considering the physical layer security, we prove that the conventional cooperation scheme actually deteriorates the secrecy performance compared to the direct transmission, given that the eavesdropper has a better channel condition to the users than the destination. In this case, the necessary...
This paper studies multi-relay compressive cooperative schemes in which the source and the relays utilize compressive sensing (CS) as joint source-channel coding (JSCC). We consider four decode-and-forward (DF) strategies to forward the CS measurements here, namely receive diversity, code diversity, successive decoding and concatenated decoding, and derive their respective achievable rates in the...
We use a per-path Rician fading model to analyze the capacity of acoustic channels, and provide experimental data to confirm the practicality of simulation results. Three power allocation policies are considered: water-filling, uniform power allocation across selected, channel-favored frequencies (“on-off” carriers in an OFDM system), and uniform power allocation across all carriers irrespective of...
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