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A worst-case model of spurious resonances which can occur in electromagnetic system consisting of an antenna, cable and transmitter output filter (or receiver input filter) is proposed. These resonances may cause significant increase in power of spurious emissions for transmitting equipment and the decrease in out-of-band radiated susceptibility levels for receiving equipment. Three amplitude-frequency...
We propose the concept of area discrimination with magnetoquasistatic (MQS) fields. Unlike radio waves, MQS fields are valid for forming a clearly defined area whose radius is below about 1 meter. Such an area can be utilized for identification of persons with mobile terminals. Since an important characteristic required for the terminals is isotropy in receiving magnetic fields, we made an isotropic...
A highly integrated Ku-band (10.7 – 12.75 GHz) planar phased array receiver of 64 antenna elements is presented. It features instantaneous reception of the full Ku-band (2.05 GHz wide) in two orthogonal polarizations with scan angles up to 75 degrees by using time delay instead of phase shift. The receiver is part of a system for satellite reception on board of moving vehicles. Two SiGe RFICs were...
A modular multichannel receiver is presented in this work to offer a flexible solution for the scalable active antenna array. Both the antenna array architecture and relevant hardware are introduced. The proposed receiver adopts direct digital synthesis (DDS) based phase shifting to achieve a phase resolution in sub-degree level. The hardware design of the RF front-end, multichannel phased signal...
Passive Intermodulation (PIM) occurring in worldwide broadcast systems has only received a very small amount of attention. This paper will focus on how and where PIM occurs in broadcast systems. Known PIM sources occurring in broadcast equipment are reviewed. PIM interference examples are provided for an ATSC DTV transmitter interfering with adjacent channel receivers. Both “static” and “dynamic”...
A Matlab implementation of the MD-GSIR algorithm is presented, including an overview of the algorithm and details of the implementation. The algorithm uses a multidimensional factor graph and iterative message passing to gradually improve the signal estimation and accounts for fading in time, frequency and space dimensions. The implementation is preliminary and its goal is to allow flexible and easy...
The ground penetrating radar (GPR) is a specialized radar used to obtain images of the objects buried under the ground surface. In this study, we discuss an experimental GPR setup that can be built using a vector network analyzer. The objective was to develop the GPR to operate in the range of 200 MHz to 700 MHz. The cavity backed bow-tie antenna, power amplifier and a low noise amplifier were used...
Phased-array receivers provide two major benefits over single-antenna receivers. Their signal-to-noise ratio (SNR) doubles for each doubling in the number of elements, resulting in extended range. Secondly, interferers can be rejected in the spatial domain for increased link robustness. These arrays can be implemented by phase shifting and summing the signals from antenna elements with uniform spacing...
A virtual multiple-input multiple-output (MIMO) system based on cooperative communication is studied actively. This system is formed between base station and source node with using of two or more nodes around itself. These transmitters are equipped with a single antenna. This system is one of the solution methods for deterioration in communication quality from that the power supply of the node is...
Network coding with multilevel modulation in distributed antenna systems is analyzed, by which the performance of the uplink can improved due to multiuser diversity. A sample system consist of 2 users with symbol-level network coding is given, where the multilevel modulation is employed at the transmitter, and a kind of maximum ratio combination scheme is used at the receiver. Both the theoretical...
An Ultra-Wideband hardware demonstrator based on Impulse Radio for Local Body Area Network applications is presented. The system includes an UWB transmitter, an UWB receiver and a microcontroller board. It operates in the frequency range from 3.1 - 5.0 GHz with a maximum data rate of 10 MBit/s. The performance of the system is shown in terms of BER. It was tested for different antennas and distances...
The paper analyses dynamics of change of multipath components in urban environment. The simulations were run over very short routes, using very fine resolution and keeping the track of a mobile station every few centimetres. The main idea behind this work was to explore the “life expectance” of each multipath component, to look into the variation rate of the appearance and/or disappearance of each...
We study the degrees of freedom (DoF) regions of two-user multiple-input multiple-output (MIMO) Z and full interference channels in this paper. We assume that the receivers always have perfect channel state information. We derive the DoF region of Z interference channel with channel state information at transmitter (CSIT). For full interference channel without CSIT, the DoF region has been obtained...
In this paper, we propose an efficient receiver design for single carrier frequency-domain equalization (SCFDE) for relay-assisted transmission scenario over frequency selective channels. Building upon our earlier work, we propose a novel minimum mean square error (MMSE)-based receiver design tailored to broadband cooperative networks. We show that, by incorporating linear processing techniques, our...
This paper investigates the problem of achieving the degrees of freedom (DoF) of a K-user multiple-input-multipleoutput (MIMO) interference channel with a MIMO relay, where each transmitter and receiver is equipped with M antennas. We propose a two-hop relay aided transmission scheme based on the idea of interference alignment to achieve the full DoF KM/2. The scheme requires global channel state...
A low power transceiver architecture for the 2.4 GHz ISM band using a 1.0 V supply is presented. It employs a transformer to convert the 100 Ω antenna impedance to almost 1 kΩ and so facilitates a low power transmitter and receiver. The simulated post-layout output power of the differential class-E power amplifier is 2.0 dBm with a drain efficiency of 28.4%. The direct-conversion receiver achieves...
We consider the asymptotic performance of a class of linear receivers in multiple-input multiple-output (MIMO) multiple access channels (MAC). Under the assumption that the number of transmitters K and the number of receive antennas N grow large at the same rate and that the receiver has only an imperfect estimate of the channel matrix, we derive deterministic equivalents for the signal-to-interference-plus-noise-ratio...
In this work, we investigate the Gaussian MIMO bidirectional broadcast wiretap channel, from the vantage point of optimal transmit strategy design, to fulfill a certain secrecy constraint. An achievable secrecy rate region is computed and the gap to the capacity region of the same channel without the secrecy constraint is upper-bounded. Moreover, for the case of single receive antennas at all terminals,...
A Gaussian multiple-input single-output (MISO) secrecy channel is considered, where a transmitter is equipped with multiple antennas, and an intended receiver and an eavesdropper each equipped with a single antenna. This paper studies the robust beamforming design in the presence of uncertainty of channel state information (CSI) on the eavesdropper channel. Under the assumption that all possible states...
Direct-conversion radio architecture is a low-cost, small-size design for the analog front-end subsystem in a wireless communication transceiver. This architecture, however, induces radio impairments such as I-Q imbalance and dc offset that, along with frequency offset, incur severe degradation in communication performance. This paper aims to improve the performance of estimation and compensation...
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