Overview of multiple antenna designs for handheld devices and base stations

Author(s):  
Chi-Yuk Chiu ◽  
Ross D. Murch
2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Grzegorz Szczepkowski ◽  
Ronan Farrell

This paper presents a study of linearity in wideband CMOS low noise amplifiers (LNA) and its relationship to power consumption in context of Long Term Evolution (LTE) systems and its future developments. Using proposed figure of merit (FoM) to compare 35 state-of-the-art LNA circuits published over the last decade, the paper explores a dependence between amplifier performance (i.e., combined linearity, noise figure, and gain) and power consumption. In order to satisfy stringent linearity specifications for LTE standard (and its likely successors), the paper predicts that LNA FoM increase in the range of +0.2 dB/mW is expected and will inevitably translate into a significant increase in power consumption—a critical budget planning aspect for handheld devices, active antenna arrays, and base stations operating in small cells.


Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2475 ◽  
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang Van Nguyen ◽  
Thi-Anh Hoang ◽  
Byung Moo Lee

In this paper, we investigate power domain division-based multiple access (PDMA) to support the base stations (BS) equipped with multiple antennas to serve mobile users. Such a system deploys multiple input single output (MISO)-based wireless transmission and a full-duplex (FD) scheme. Furthermore, such MISO PDMA system consists of BS employing transmit antenna selection to reduce complexity in signal processing at the receivers. We distinguish two kinds of mobile users, device-to-device (D2D) users and traditional users. In such MISO PDMA, there exists a trade-off between outage performance of each PDMA user and power allocation factors. Since the implementation of the FD scheme at PDMA users, bandwidth efficiency will be enhanced despite the existence of self-interference related to such FD. In particular, exact expressions of outage probability are derived to exhibit system performance with respect to D2D users. Finally, valuable results from the simulated parameters together with the analytical results show that MISO PDMA can improve its performance by increasing the number of transmit antennas at the BS.


Author(s):  
John G. Michopoulos ◽  
Panayota Tsompanopoulou ◽  
Elias N. Houstis ◽  
Anupam Joshi ◽  
Sasikanth Avancha ◽  
...  

The present paper is motivated by the need to develop technological infrastructure for informed and reliable decision support in various crisis and disaster management situations. It describes our prototype data-driven fire hazard simulator capable of predicting fire propagation dynamics that allows the user to take decisions based on reliable micro-future predictions of fire propagation based on potential personnel actions. Several heterogeneous technologies are integrated to achieve this goal. The GRID is utilized for running legacy codes enabling fire-propagation prediction. Sensor networks are used to enable simulation steering and correction. Base-stations enable data and communications coordination. Handheld or other wearable devices are terminal and initial points of interaction of the first responders with the rest of the system. Agent middleware is utilized to coordinate all heterogeneous software present. A demonstration of the first incarnation of this infrastructure is implemented over Bluetooth and WiFi enabled communications between the handheld devices and the base-stations involved.


Public exposure to Electromagnetic Radiation, which abbreviatedly known as EMR is a recurring phenomenon and it becomes among the factors contributing to the public concerns. EMR represents a new technology, such as base stations, overhead power lines and other sources of exposure, that is difficult to control by the affected individual. Non-ionizing and ionizing radiation are two major divisions of the electromagnetic spectrum. Both kinds of radiation can be differentiated based on which one has enough energy to knock electrons off atoms upon collision, as well as capable to give out lower-energy harm, such as breaking chemical bonds in molecules. Ionizing radiation is a type of radiation that has a short wavelength to interact with the electrons in biological chemicals. Alpha, beta, and gamma rays are examples of ionizing radiation. The literature on RF effects also focused on the human factor and health parameters, both from the laboratory and epidemiological study perspectives. The presence of this communication technology has given rise to media and public concerns about the possibility of RF radiation emitted by computers, phones and base stations that might cause a rise in diseases that affect the reproductive system, neurobehavioral parameters and various forms of cancers, especially brain tumours. More recently, concerns about the possible effects culminating from the massive development of base stations coupled with increasing use of mobile phones have begun to appear due to the enormous growth of wireless mobile communication, mainly handheld devices. This has led to increased apprehension as to whether non-ionizing radiation (NIR) used in present technologies could have short, medium and long-term biological effects.


Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4210
Author(s):  
Tae-Kyoung Kim

This paper considers a downlink cellular network where multi-antenna base stations (BSs) simultaneously serve their associated multi-antenna users. Each BS is distributed according to a homogeneous Poisson point process and uses zero-forcing beamforming for spatial division multiplexing with partial channel state information (CSI). During downlink transmission, each user combines the multiple antenna outputs and quantizes the CSI to feed back to its associated BS. Specifically, this paper focuses on antenna combining at the receiver. Conventional quantization-based combining (QBC) effectively reduces the quantization error; however, inter-cell interference in the cellular networks degrades the QBC gain. This degradation is analyzed using a spherical-cap approximation of vector quantization (SCVQ). From the SCVQ, the ergodic spectral efficiency and the optimal number of feedback bits are investigated, and it is shown that the QBC degrades the gain of the effective channel. To address this problem, an optimization solution is proposed that selects the antenna combining to maximize the spectral efficiency. The solution is also derived by considering the expected beamforming vectors of other cells. It is demonstrated by simulation that the proposed solution outperforms the conventional methods.


2011 ◽  
Vol 20 (1) ◽  
pp. 34-37 ◽  
Author(s):  
David Chapple

Abstract Over the past 20 years, there have been many advances in the computer industry as well as in augmentative and alternative communication (AAC) devices. Computers are becoming more compact and have multiple purposes, such as the iPhone, which is a cell phone, mp3 player, and an Internet browser. AAC devices also have evolved to become multi-purpose devices; the most sophisticated devices have functionality similar to the iPhone and iPod. Recently, the idea of having the iPhone and iPad as a communication device was initiated with the development of language applications specifically for this format. It might be true that this idea could become the future of AAC devices; however, there are major access issues to overcome before the idea is a reality. This article will chronicle advancements in AAC devices, specifically on access methods, throughout the years, towards the transition to handheld devices. The newest technologies hold much promise with both features and affordability factors being highly attractive. Yet, these technologies must be made to incorporate alternate access if they are to meet their fullest potential as AAC tools.


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