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Designing practical methods that target achieving the ideal data hiding capacity is one of the main foci of data hiding field. High dimensional quantization enables to narrow the gap between ideal and actual capacities. However, computational complexity becomes a prohibitive factor. Lattice based quantization appears to be a good candidate for practical solutions. In this paper, it is shown that TCQ-IS,...
In this paper, we directly lower bound the information capacity for channels with independent identically distributed (i.i.d.) deletions and duplications. Our approach differs from previous work in that we focus on the information capacity using ideas from renewal theory, rather than focusing on the transmission capacity by analyzing the error probability of some randomly generated code using a combinatorial...
Fast recovery from failures and efficient allocation of link capacities in a network for guaranteeing seamless communication services are two primary goals of network survivability design. Shared backup path protection (SBPP) technique has been shown to be a promising solution to tackle these problems, due to sharing capacity among protection paths. The level of capacity sharing that can be achieved...
The problem of finding an optimal path in an uncertain graph arises in numerous applications, including network routing, path-planning for vehicles, and the control of finite-state systems. While techniques in robust and stochastic programming can be employed to compute, respectively, worst-case and average-optimal solutions to the shortest-path problem, we consider an alternative problem where the...
This paper presents an experimental characterization of the ultra-wide bandwidth (UWB) indoor channel based on an extensive measurement in a PC tower case environment to identify the optimum channel performance. The investigation is based on the analysis of the statistical properties of the multipath profiles, measured over a finely spaced measurement grid. The small-scale statistics of the received...
Closed-form expressions for the capacity of dual-selection combining and maximal-ratio combining diversity systems over slowly varying correlated Hoyt fading channels has been presented. Different power and rate adaptation techniques available in the literature has been considered for the capacity analysis. A study on the effects of correlation and fading parameters on the channel capacity of the...
We consider a three-terminal Gaussian relay channel corrupted by a Gaussian interference. We assume that the interference is non-causally known to only some, i.e, not to all, the terminals. We examine two different scenarios: 1) both the source and the relay, but not the destination, know the interference and collaborate to cancel out its effect and 2) only the source knows the interference. The first...
Network covert channels can be used to transfer secret information in network protocols. For a kind of network covert channels hidden in overt sources with fixed probability distribution, we propose a modified Pearson chi-square test which improves detection accuracy. We incorporated adjacent probability values and divided the new distribution into two partitions sensitive to different hidden sections...
This paper studies the use of amplify-and-forward (AF) relays for robust beamforming, with the aid of imperfect channel state information (CSI) at the sender. In particular, the maximization of the worst-case signal-to-noise ratio (SNR) at the destination terminal is studied under a bounded spherical region for the norm of CSI error vector. We show that under a condition on the estimated CSI quality,...
Fading channels, which are used as a model for wireless communication, are often analyzed by assuming that the receiver is aware of the realization of the channel. This is commonly justified by saying that the channel varies typically slowly with time, and the receiver is thus able to estimate it. However, this assumption is optimistic, since it is prima facie not clear whether the channel can be...
In this paper, we study the capacity of cognitive networks. We focus on the network model consisting of two overlapping ad hoc networks, called the primary ad hoc network (PaN) and secondary ad hoc network (SaN), respectively. PaN and SaN operate on the same space and spectrum. For PaN (or SaN resp.) we assume that primary (or secondary resp.) nodes are placed according to a Poisson point process...
Shared-memory concurrency is the prevalent paradigm used for developing parallel applications targeted towards small- and middle-sized machines, but experience has shown that it is hard to use. This is largely caused by synchronization primitives which are low-level, inherently nondeterministic, and, consequently, non-intuitive to use. In this paper, we present the Nornir run-time system. Nornir is...
In MIMO multi-relay systems, close-loop precoding at relay nodes is not necessary if unicast modes are carried out. However, in unicast modes, the inter-stream interference at relay nodes may degrade the system capacity. In this paper, two unicast modes are proposed to reduce the negative impact of the residual interference. The first one suppresses the interference by applying orthogonal precoding...
Information-theoretic security offered by the wiretap channel model has been extensively studied for various scenarios recently. One scenario that has not received much attention is secrecy for systems with memory in the form of input constraints or inter-symbol interference (ISI). In this work, we consider finite state wiretap channels (FSWCs), which model the scenario of secrecy with memory. Using...
Channel polarization, originally proposed for binary-input channels, is generalized to arbitrary discrete memoryless channels. Specifically, it is shown that when the input alphabet size is a prime number, a similar construction to that for the binary case leads to polarization. This method can be extended to channels of composite input alphabet sizes by decomposing such channels into a set of channels...
The fading number of a noncoherent two-user Rician fading channel is derived. The fading number is the second term in the high-SNR expansion of the sum-rate capacity of this multiple-access channel. It is shown that the fading number is identical to the fading number of the single-user Rician fading channel that is obtained when the user seeing the worse channel is switched off.
Wireless sensor networks have attracted much attention recently with ubiquitous or ad hoc applications. Wireless sensor nodes may be deployed on some fields and organize themselves in a large scale ad hoc network. A path diversity is an effective technique to get highly reliable communications in the sensor networks. In this paper, the capacity and cutoff rate of binary tree network composed of BSC...
This paper argues that the speed-accuracy trade-off arises as a consequence of Shannon's fundamental theorem for a channel with noise, when coupled with two additional postulates: that people are imperfect information processors, and that motivation is a necessary condition of the speed-accuracy tradeoff.
The capacity of feedback links is typically limited and shared by multiple users. So this paper studies the impacts on multiple input multiple output (MIMO) broadcast channel (BC) when limited feedback capacity is shared among multiple users. Our mathematical analysis proves that in the high signal-to-noise ration (SNR) region, allocating the whole feedback capacity to a single user is the optimal...
In this paper, we highlight the impact of variable Push-To-Talk (PTT) delays on performance of a heterogeneous Land Mobile Radio (LMR) network. We first present the PTT delay values and distributions observed for some commonly used LMR nodes. An analytical model is then developed to estimate the asymmetric throughput problem. The results obtained using this model and simulations show that a LMR node...
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