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Massive multiple-input multiple-output (MIMO) relaying is a promising technological paradigm which can offer high spectral efficiency and substantially improved coverage. Yet, these configurations face some formidable challenges in terms of digital signal processing (DSP) power consumption and circuitry complexity, since the number of radio frequency (RF) chains may scale with the number of antennas...
Energy harvesting from ambient radio frequency (RF) radiation is an efficient approach to provide wireless energy replenishment for mobile devices. At the same time, introducing active/sleep modes in base stations (BSs) is an effective method to save the energy consumption of cellular networks. However, the performance of the two techniques would be dependent and interact with each other if both of...
In this paper, we study a problem where multiple operators (OPs) need to share a common pool of spectrum with each other. Our objective is to maximize the social welfare, defined as the overall weighted sum rate of the OPs. The problem is decomposed into two parts: the first part is to allocate RBs to OPs, which we do so by extending the framework of many-to-one matching game with externalities. The...
In this paper, we consider the design of two-stage beamformers for the downlink of multi-user frequency-division-duplexing (FDD) massive multiple-input multiple-output (MIMO) systems. We consider the case that both link ends are equipped with hybrid analog/digital (HDA) beamforming structures. With analog beamforming and user grouping based on the second-order channel statistics, the user equipment...
The demand on highly-integrated, low-cost radios solution dictates the development of RFSoC targeting the 3G market. By integrating connectivity radios, such as WiFi, Bluetooth, GPS, and FM, the world's 1st 3G RFSoC solution was presented in this pager using TSMC 28nm CMOS process with low-cost single-layer wire-bond CSP package. With fully consideration on interference and co-existence, excellent...
Considering a broadband co-frequency and co-time full duplex (CCFD) transceiver, which transmits and receives at the same time and frequency resources, the previous studies propose many self-interference cancellation algorithms in the radio frequency (RF) domain, but lack their performance analysis. Therefore, we make an attempt to analyze the optimal self-interference cancellation performance in...
The radio frequency (RF) spectrum becomes overly crowded in some indoor environments due to the high density of users and bandwidth demands. To accommodate the tremendous wireless data demands, efficient spectrum-sharing approaches are highly desired. To this end, this paper introduces a new spectrum sharing solution for indoor environments based on the usage of a reconfigurable reflect-array in the...
Light Fidelity (LiFi) uses light emitting diodes (LEDs) for high speed wireless communications. Since employing a different range of the electromagnetic spectrum from radio frequency (RF) communications, LiFi can significantly alleviate the traffic bottlenecks in high density RF scenarios, typically present in an indoor environment. Hence, a combination of LiFi and RF networks becomes a promising...
The coexistence of broadband systems with currently deployed Professional Mobile Radio (PMR) communication systems like Public Protection and Disaster Relief (PPDR) has gained much deserved attention. In the recent literature, it has been suggested that LTE-like FBMC-OQAM system working on linear devices can coexist in PMR band, while conventional OFDM-based LTE system fails. When we take into account,...
In order to analyze the reason of electromagnetic (EM) interference between the BeiDOU and GPS receivers, the behavior model of RF front-end for the GPS receiver is built, and the IF output which is interfered by the BeiDou transmit signal is simulated. The simulation results are validated by the experiment. Both the simulation and experiment results show that the GPS RF front-end is suppressed due...
In the opportunistic beamforming (OBF) scheme, the access point (AP) acquires channel related feedback from the network's terminals and allocates the orthonormal beams to the users with the best link. This paper investigates the OBF scheme in a wireless powered communication network, where multi-antenna terminals with wireless power harvesting capabilities are randomly deployed around the AP. In this...
Light Fidelity (LiFi) is a recently proposed technology that combines illumination and high speed wireless communication using light emitting diodes (LEDs). Since the used electromagnetic spectrum does not overlap with the radio frequency (RF) spectrum, a small cell LiFi attocell network can be added to the conventional RF network as an additional networking layer in order to mitigate the data traffic...
The digital-analog hybrid beamforming technique with a number of antennas is necessary for the millimeter wave (mmWave) communications to overcome both high complexity of large array system and high path loss of mmWave signals. Since the hybrid beamforming system has multiple radio-frequency (RF) chains, the simultaneous transmission is possible which is known as the space division multiple access...
In this paper, a novel X-Duplex relay scheme with one source, one amplify-and-forward (AF) relay and one destination is proposed. The relay is equipped with a shared antenna and two radio frequency (RF) chains used for transmission or reception. The proposed scheme can be reduced to either full-duplex (FD) or half-duplex (HD) with different RF chain configurations. In the proposed scheme, relay adaptively...
Wireless sensor networks (WSNs) currently see a strong increase in demand for various industrial applications like smart testing and production systems. Open frequency bands (e.g. 2.4 GHz) allow the use of commercial low-cost hardware, but need to be shared with other devices and systems, leading to interference and therefore transmission errors. Re-transmitting damaged packages might eventually succeed,...
The amount of radio spectrum available for command and control (C2) radio links of unmanned aircraft (UA) systems (UAS), and the effectiveness with which that spectrum is used, will strongly affect the eventual number of remotely piloted UAS that can safely operate within U.S. airspace. In this paper we analyze several possible methods for utilizing available UAS C2 spectrum as efficiently as possible...
Wireless sensor networks (WSNs) currently see a strong increase in demand for various industrial applications like smart testing and production systems. Open frequency bands (e.g. 2.4 GHz) allow the use of commercial low-cost hardware, but need to be shared with other devices and systems, leading to interference and therefore transmission errors. Re-transmitting damaged packages might eventually succeed,...
Heterogeneous networks has recently evolved as one of the key enablers for future wireless technologies. The extremely growing mobile market, together with the arising demand for high data rates, force to off-load the main cellular network traffic. This can be accomplished by deploying small cells within the macro evolved-node base-station (eNodeB) coverage. Thus, more User Equipments (UEs) in the...
Reconfigurable RF circuits are expected to become essential microwave components of next-generation wireless-communications and radar systems. In this paper, the usefulness of a tunable notch filter for interference mitigation is evaluated. In particular, the effects of an unintentional interference tone on the imaging performance of a coherent frequency-modulated-continuous-wave (FMCW) radar are...
Reconfigurable RF circuits are expected to become essential microwave components of next-generation wireless-communications and radar systems. In this paper, the usefulness of a tunable notch filter for interference mitigation is evaluated. In particular, the effects of an unintentional interference tone on the imaging performance of a coherent frequency-modulated-continuous-wave (FMCW) radar are...
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