126,337 research outputs found
Mobile Jammers for Secrecy Rate Maximization in Cooperative Networks
We consider a source (Alice) trying to communicate with a destination (Bob),
in a way that an unauthorized node (Eve) cannot infer, based on her
observations, the information that is being transmitted. The communication is
assisted by multiple multi-antenna cooperating nodes (helpers) who have the
ability to move. While Alice transmits, the helpers transmit noise that is
designed to affect the entire space except Bob. We consider the problem of
selecting the helper weights and positions that maximize the system secrecy
rate. It turns out that this optimization problem can be efficiently solved,
leading to a novel decentralized helper motion control scheme. Simulations
indicate that introducing helper mobility leads to considerable savings in
terms of helper transmit power, as well as total number of helpers required for
secrecy communications.Comment: ICASSP 201
Model structure selection using an integrated forward orthogonal search algorithm assisted by squared correlation and mutual information
Model structure selection plays a key role in non-linear system identification. The first step in non-linear system identification is to determine which model terms should be included in the model. Once significant model terms have been determined, a model selection criterion can then be applied to select a suitable model subset. The well known Orthogonal Least Squares (OLS) type algorithms are one of the most efficient and commonly used techniques for model structure selection. However, it has been observed that the OLS type algorithms may occasionally select incorrect model terms or yield a redundant model subset in the presence of particular noise structures or input signals. A very efficient Integrated Forward Orthogonal Search (IFOS) algorithm, which is assisted by the squared correlation and mutual information, and which incorporates a Generalised Cross-Validation (GCV) criterion and hypothesis tests, is introduced to overcome these limitations in model structure selection
Peer-to-Peer Cooperative Positioning Part I: GNSS Aided Acquisition
To improve the performance of GNSS receivers in hostile environments, we consider a Cooperative Positioning approach, where receivers exchange data and information with their neighbors. We focus on unstructured P2P networks, without a control or fusion center. We show that a significant reduction of the acquisition time can indeed by achieved when GNSS aiding quantities like Doppler, satellite Carrierto-Noise ratio and secondary code delay are provided by some aiding peers. The approach is clearly similar to that of Assisted GNSS, but does not require a fixed infrastructure and may better take into account the local environment. Since, in the near future, multi-standard devices will be more and more inter-connected, GNSS Cooperative Positioning may soon become an alternative or a complement to
fixed augmentation system
Wireless Communications in the Era of Big Data
The rapidly growing wave of wireless data service is pushing against the
boundary of our communication network's processing power. The pervasive and
exponentially increasing data traffic present imminent challenges to all the
aspects of the wireless system design, such as spectrum efficiency, computing
capabilities and fronthaul/backhaul link capacity. In this article, we discuss
the challenges and opportunities in the design of scalable wireless systems to
embrace such a "bigdata" era. On one hand, we review the state-of-the-art
networking architectures and signal processing techniques adaptable for
managing the bigdata traffic in wireless networks. On the other hand, instead
of viewing mobile bigdata as a unwanted burden, we introduce methods to
capitalize from the vast data traffic, for building a bigdata-aware wireless
network with better wireless service quality and new mobile applications. We
highlight several promising future research directions for wireless
communications in the mobile bigdata era.Comment: This article is accepted and to appear in IEEE Communications
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