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In this paper, we present an analytical lower bound on the ergodic capacity of optical multiple-input multiple-output (MIMO) channels. It turns out that the optical MIMO channel matrix which couples the mt inputs (modes/cores) into mr outputs (modes/cores) can be modeled as a sub-matrix of a m × m Haar-distributed unitary matrix where m > mt, mr. Using the fact that the probability density of the...
5G wireless communication envisions unprecedented changes in current mobile networks in order to guarantee significant higher performance mainly in terms of data rates, latencies and efficiency. This paper provides an analytical model based on stochastic geometry, in order to address the planning and the dimensioning of 5G Cloud RAN. The results shows the requirements in terms of number of virtual...
In the most basic sense, a network is any collection of objects in which some pairs of these objects are connected by links. In a network of objects, objects can be people or computers, which we refer to them as nodes of the network. Social links among friends play an important role in dictating their behavior. In online social networks (OSNs), these social links determine the flow of information...
This paper studies the RSU deployment problem in a 2-D urban or suburban road scenario of a vehicular ad hoc network (VANET). To optimize RSU deployment, we introduce the notion of centrality in a social network to RSU deployment, and use it to measure the importance of an RSU position candidate in RSU deployment. Based on the notion of centrality, we propose a centrality-based RSU deployment approach...
Crowd management in urban settings has mostly relied on either classical, non-automated mechanisms or spontaneous notifications/alerts through social networks. Such management techniques are heavily marred by lack of comprehensive control, especially in terms of averting risks in a manner that ensures crowd safety and enables prompt emergency response. In this paper, we propose a Markov Decision Process...
We investigate the capacity of energy harvesting binary symmetric channels with deterministic energy arrival process and finite battery size. Using an abstraction of the physical layer, binary symbols are transmitted. A cost function is associated with each transmitted symbol. Upper and lower bounds on the channel capacity are derived as functions of the normalized exponent of the cardinality of the...
Large absolute channel bandwidths at millimeter wave (mmWave) frequencies and more directional antenna gains may lead to quasi-deterministic (less random) channel fading behavior. Randomness in the cross polarization discrimination (XPD) is an attribute related to the channel fading behavior. In narrow-band channels, it is usually modeled as a log-normal random variable. From channel modeling perspectives,...
FilterBank MultiCarrier (FBMC) is a candidate waveform for the coming fifth generation of mobile communications. The major advantage of FBMC is its very good frequency localization, provided that a high overlapping factor is used. Obviously the drawback is the poor time localization of the signal. In this paper we nevertheless show that it is possible to design a FBMC system with quite strong time...
In the time-division-duplex (TDD) system, the channel state information (CSI) is mainly obtained through channel estimation. The active eavesdropper is able to attack the channel estimation phase by sending the same pilot signals as the legitimate users send to the base station without being detected, which can destroy the CSI acquired through channel estimation and greatly decrease the communication...
In this paper, we propose a novel pilot beamforming and CSI acquisition strategy for IoT systems to achieve reduction in pilot overhead and enhancement in the channel estimation quality. Key idea of the proposed technique, called time-domain sparse beamforming (TDSB), is to sparsify the time-domain channel vector using the antenna-domain beamforming. As a result of TDSB, wideband channel information...
With the rapid development of science and technology, unmanned aerial vehicles (UAVs) gradually become the worldwide focus of science and technology. Not only the development and application but also the security of UAV is of great significance to modern society. Different from methods using radar, optical or acoustic sensors to detect UAV, this paper proposes a novel distance-based support vector...
Mobile services, especially video streaming, has seen a rapid usage increase in recent years. Base stations (BSs) need to employ smarter and efficient resource allocation strategies to maintain high quality of service (QoS) to users at all the times. Predictive resource allocation (PRA), is one such novel scheme, in which BSs seek to anticipate the user demands and offer service to users in advance...
The causality of gait freezing in patients with advanced Parkinson's disease is still not fully understood. Clinicians are interested in investigating the freezing of gait (FoG) histogram of patients in their daily life. To that end, one needs a real-time signal processing platform that can help record freezing information (e.g., timing and the duration of every gait freezing occurrences). Wearable...
In this paper we propose a low-computational-complexity channel estimation algorithm for the downlink of massive MIMO systems. This algorithm employs the expectation propagation and expectation maximization techniques, assuming a sparsity promoting conditional Gaussian prior distribution on the channels. Its computational complexity scales only linearly with the number of transmit antennas, the number...
As latency sensitive applications, such as online video chatting and virtual reality become popular, end-to-end latency prediction is becoming an important problem. Traditional methods for latency prediction are static, and are unsuitable to predict time-varying round-trip times between the servers and edge devices. Though distance-feature decomposition is able to predict time-varying round-trip times...
In this paper we propose a novel online caching method to perform the update phase in a distributed caching system, with a natural application to heterogeneous scenarios with cache-equipped small-cell base stations. We investigate the performance of our scheme, showing in particular that it results in a significant reduction of backhaul load, to the point of converging to the performance of the optimal...
IoT wireless connectivity often presents a lossy and error prone radio link layer between the wireless edge device and the wireless base station. Data transacted over the radio link layer often uses TCP, which provides programmatic error mitigation elements, e.g., loss of and out-of-order packet detection, combined with ACK/NACK from far end to trigger packet retransmission. In the use case of subscription...
Non-orthogonal multiple access (NOMA) is considered as a promising technology for the fifth generation mobile communications. Energy-efficient resource allocation scheme is studied for a downlink NOMA wireless network, where multiple users can be multiplexed on the same subchannel by applying successive interference cancellation technique at the receivers. Most previous works focus on resource allocation...
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