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Suppose that a rumor originating from a single source among a set of suspects spreads in a network, how to root out this rumor source? With the a priori knowledge of suspect nodes and a snapshot observation of infected nodes, we construct a maximum a posteriori (MAP) estimator to identify the rumor source using the susceptible-infected (SI) model. We propose to use a notion of local rumor center to...
Multiple-input multiple-output (MIMO) radar with colocated antennas is expected to achieve good imaging performance via coherent processing. However, a crucial factor to this process-phase synchronization, which directly determines the performance gain, has rarely been studied in previous works. Hence in this paper, given the sparsity of the target, we address the problem of imaging for colocated...
As the communication network is in transition towards a commercial one controlled by service providers (SP), the present paper considers a pricing game in a communication market covered by several wireless access points sharing the same spectrum and analyzes two business models: monopoly (APs controlled by one SP) and oligopoly (APs controlled by different SPs). We use a Stackelberg game to model...
Pricing in telecommunication networks has received much attention in recent years, as the huge commercial interest drives the transition from a monopolistic network to a commercial one with competitive service providers (SPs). The present paper considers a pricing game in a communication market covered by two wireless access points (APs) and analyzes two commercial models: monopoly (two APs controlled...
Frequency division linear frequency modulation multiple-input-multiple-output (FDLFM-MIMO) radar may provide an efficient way to synthesize a high-resolution range profile (HRRP) and has attracted more attention. Unfortunately, the conventional methods based on Matched Filter (MF) show high sidelobes and can not get the expected range resolution. In this paper, a sparsity-driven imaging method is...
Gossiping or rumor spreading is an effective way of information dissemination, and gossiping-based schemes are promising solutions for many of the next generation networks. Despite the abundant existing works on (high-probability) completion time of gossiping processes, it remains an interesting, important, and largely unaddressed problem how to select the initial information sources for gossiping,...
The inability for most existing detection methods to effectively distinguish between a wireless microphone signal and a sinusoidal continuous wave (CW) interference has led to an excessively high false alarm rate and thus severely limited the utility of sensing-based cognitive transmission in the TV white space (TVWS) spectrum. Two potential solutions are proposed, in which the first solution focuses...
This paper presents results of a study about the statistical properties of noise (including unknown interference) in blank channels of TV bands, i.e., TV white spaces. Measurements were conducted to collect data in three different scenarios: sunny-day laboratory, sunny-day curbside and rainy-day laboratory. Impulsive noise has been modeled as a pulse train and the pulse amplitude, pulse duration time...
Hierarchical macrocell and femtocell networks aim to provide seamless roaming and improve network capacity. UEs moving in such networks may experience frequent handovers. In this paper, a handover decision algorithm considering data arrival, handover delay and signaling cost is proposed based on Markov decision processes. The expected total reward seeks a balance between transmission latency and handover...
This paper addresses a robust downlink beamforming optimization problem for the multigroup multicast scenario, when only imperfect channel state information (CSI) is available at the transmitter. We consider two different optimization criteria: minimizing the total transmit power subject to quality of service (QoS) constraints at each receiver; max-min fair (MMF) signal-to-interference- plus-noise...
IEEE-802.11-based WLAN MAC performance evaluation is of great importance, especially under non-saturated conditions. A new load equation, respect to the non-saturation, is proposed for analysis of the MAC mechanism in this paper. The load equation together with a backoff equation and a transmission equation are sufficient to analyze the MAC performance under non-saturated conditions. In the new load...
Providing a uniform and non-disrupted service is of paramount importance for numerous applications. However, such a goal becomes challenging when the resource for providing service is supplied by a source which is stochastic in nature; examples include a media player whose content is received from a remote database via a unreliable network connection, or a base station whose power supply is from a...
This paper proposes a reliability-admissible filtering mechanism to generate the reasonable route set for the traditional SUE model. This mechanism still takes into account traveler's cost-susceptivity, which is able to dispel the impact of dimension on the traffic assignment. The filtering formula is presented and further estimated based on the Gumbel distribution assumption for the route disutility...
For two-tier networks consisting of macrocells and femtocells, the channel access mechanism can be configured to be open access, closed access, or hybrid access. Hybrid access arises as a compromise between open and closed access mechanisms, in which a fraction of available spectrum resource is shared to nonsubscribers while the remaining reserved for subscribers. This paper focuses on a hybrid access...
With the blasting increase of wireless data traffic, incumbent wireless service providers (WSPs) face critical challenges in provisioning spectrum resource. Given the permission of unlicensed access to TV white spaces, WSPs can alleviate their burden by exploiting the concept of “capacity offload” to transfer part of their traffic load to unlicensed spectrum. For such use cases, a central problem...
In order to extract cloud cover feature from ISCCP D2 dataset, a method of feature extraction using wavelet and statistics was used. This method concerned the characteristic of the cloud cover and the applications requirement, and combined the autocorrelation function, partial autocorrelation function with the wavelet method. We can get the conclusion from the features: (1) the features from wavelet...
In this article, we examine and provide insights into the frequency domain ICA approach. We develop the concept of a dynamic random process to model the frequency domain source signals. It formalizes the concept of signals that are stationary in a frame but exhibit dynamics at the frame level. Frame dynamics is an important characteristics of these signals and this work demonstrates its significant...
A setup of simple binary hypothesis testing is examined, where independent and identically distributed statistics are sequentially accumulated until either the accumulation exceeds a decision threshold (thus deciding the alternative hypothesis), or the time horizon passes a deadline (thus deciding the null hypothesis). Unlike in other adaptive procedures such as sequential probability ratio test,...
In tone reservation (TR) methods, the high peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals is reduced through exploiting the reserved tones, i.e., peak-reduction tones (PRT), so as to manipulate the clipping noise generated from the soft limiter with predefined clipping threshold. In this work, from the least-squares perspective, the PRT are designed...
In this paper, the selective harmonic elimination (SHE) technique is investigated to eliminate harmonic brought by PWM inverter. This technique involves the solutions of nonlinear, transcendental equations set representing the relation between the amplitude of fundamental wave and each order harmonic and the switching angles. Newton iteration method is usually applied to solve the equations set, but...
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