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The multi-band carrier-less amplitude and phase (m-CAP) modulation technique has been demonstrated as a significant candidate for use in visible light communication (VLC) systems, as spectral efficiency becomes ever more important. When employing m-CAP modulation, the signal bandwidth is typically split into m equally distributed subcarriers regardless of the −3 dB bandwidth. Thus, in this paper we...
With the rapid development of light-emitting diode (LED) industry, interest in visible light communication (VLC) has been growing. In this paper, we investigate on the performance of different shaped 16-QAM constellations in the application of VLC and experimentally demonstrate the superiority of a novel shaped 16-QAM named Multi-Modulus Circular (1,5,10) with a single color data rate of 1.96Gbit/s...
The multi-user multiple-input single-output (MU-MISO) visible light communications (VLC) system, which can serve multi-users simultaneously, have been widely studied in recent years. Dimming control is one of the main topics in VLC systems. In this paper, we proposed a novel transmit antenna selection based spatial dimming (TAS-SD) scheme for zero forcing (ZF) precoded MU-MISO VLC systems. By taking...
This paper proposes a constellation design for color shift keying (CSK) based on phase shift keying (PSK) conversion, to be used in cascaded power line communications (PLC) and visible light communications (VLC) systems integration. We optimize the design of MPSK-CSK constellations and analyze the performance of MPSK-CSK systems based on the optimized Euclidean distance calculated on the red-green-blue...
In visible light communication (VLC) systems, optical orthogonal frequency division multiplexing (O-OFDM) is an appealing modulation. Among many proposed O-OFDM schemes, both direct current biased O-OFDM (DCO-OFDM) and asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) are widely used. Since VLC needs to take the dual requirements of illumination and communication...
In this paper, we consider wireless information and power transfer in a cooperative multi-relay network (MRN) with relay selection. The off-grid relay terminals, which are randomly deployed within a certain cooperating area, help forward the source information to the destination following a decode-and-forward protocol. Adaptive power splitting is employed at each relay that attempts to decode the...
We consider an energy harvesting (EH) based cooperative relaying network, where two half-duplex relays can alternatively forward source data to the destination. The power-splitting technique is implemented at each relay. That is, part of the received source signal and inter-relay interference is allocated for the EH, while the remaining part is used for the information decoding (ID). The inter-relay...
Cooperative energy relaying helps in improving the radio frequency (RF) energy transfer (ET) efficiency by harvesting the otherwise dissipated energy and then transferring it to the nearby energy receiver. The achievable RF-ET gains are strongly influenced by the relative relay placement (RP), which may cause blocking of the direct energy transfer (DET) path between RF source and receiver, or energy...
Multiple-input multiple-output (MIMO) systems are well suited for millimeter-wave (mmWave) wireless communications where large antenna arrays can be integrated in small form factors due to tiny wavelengths, thereby providing high array gains while supporting spatial multiplexing, beamforming, or antenna diversity. It has been shown that mmWave channels exhibit sparsity due to the limited number of...
Our aim is to investigate long range predictions (up to several wavelengths) of the small-scale fading of radio channels. The purpose is to enable advanced 5G downlink transmission schemes that require accurate channel state information at transmitters, such as massive MIMO and coherent joint transmission, for vehicular users.
Large-scale multi-cell multi-user multiple-input multiple-output (MU-MIMO) is expected to be one of the enabling technologies for fifth generation (5G) time division duplexing (TDD) systems. One of the major challenges faced by this technology is the pilot contamination issue where interference from users in the neighboring cells may significantly impact the performance of the channel estimation process...
The growing demand on data to enhance the user experience has motivated research toward increasing the efficiency of spectrum utilization by extending cellular technology such as LTE toward unlicensed bands. In order to study the effect of channel access priorities on coexistence of several LAA networks, we consider load based equipment (LBE) based MAC protocol where we use stochastic geometry to...
We model the problem of infrastructure sharing among mobile network operators (MNOs) as a multiple-seller single-buyer market where the MNOs are able to share their own base stations (BSs) with each other. First, we use techniques from stochastic geometry to find the coverage probability of the infrastructure sharing system and analyze the trade-off between increasing the transmit power of a BS and...
This paper focuses on the optimization of routing and interference-aware resource allocation for a wireless backhaul network, focusing on the end-to-end delay minimization. We adopt a convex optimization formulation, which allows the decomposition of the problem, separating the network-plane and the communications-plane, and also allows an easy interpretation of results. We integrate the solution...
Lately Video Sensor Networks (VSN) are increasingly being used in the context of smart cities, smart homes, for environment monitoring, surveillance, etc. In such systems, due to limitations in the video sensor node resources, the most important factor is energy efficiency. Sensing, processing and transmitting are the main contributors to energy consumption in a video sensor node. Among these, wireless...
In this paper, we propose an energy efficient motion detection and power management mechanism, called sleepyCAM, for wireless camera sensor nodes that do not otherwise support low-power modes. In the proposed solution, a low-power sensor node accompanied with a Pyroelectric Infrared (PIR) sensor and a relay is used to detect motion and manage the power usage of a high-power and high-resolution camera...
Larger share of total energy consumed by mobile network operators (MNOs) is wasted to ensure seamless coverage. Three to six MNOs covering the same geographical area results in even more energy waste. Division of scarce resource, i.e., spectrum into small chunks also deteriorates the overall performance. With exponential growth of the traffic and insignificant marginal revenue, it is time for the...
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