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A small supergain circular array with electronic scanning and "zoom-in" features has been proposed. The array utilizes the orthogonal modes existing in the array systems as bases for beamforming. A mode-decomposition network is proposed that separates the different modes into different circuit ports and matches them individually. Consequentially the modes can be combined to achiever higher...
Millimeter-wave OFDM wireless personal area network system applying adaptive modulation for grouped sub-carriers was newly developed. It is composed of 100 MHz sampling speed OFDM modems which can employ adaptive modulation for every 8 neighbored subcarriers, and 70-GHz band self-heterodyne transceivers equipped with receiver space diversity. The detailed specifications and the expected maximum throughput...
This paper provides a strategic overview of the current considerations relating to the continuous network and radio technology development for evolving the mobile industry beyond the third generation standards. It also addresses some fundamental requirements that are important to mobile operators, as the basis for working with the wireless industry and supplier community to derive the "best possible"...
This paper proposes a new approach to reduce the sampling rate in delta-sigma (DeltaSigma) transmitters and, hence, to lower considerably the speed requirements of all critical digital circuit blocks. The proposed method relies on oversampling the signal by inserting zeros after the low-pass DeltaSigma-modulation and to use one of the harmonic outputs of the sampler instead of its fundamental. The...
Notice of Violation of IEEE Publication Principles"A -5OdBc Spur 0.13 μm CMOS Ring Oscillator PLL for DBS Satellite Receiver SOCs Using a Multi-Regulator Architecture"by Maxim, A.; Poorfard, R.; Kao, J.;in the Proceedings of the 2007 IEEE Radio and Wireless Symposium,Jan. 2007 Page(s):427-430After careful and considered review, it has been determined that the above paper is in violation...
Most usage scenarios for ad hoc and wireless sensor networks (WSN) require some degree of one-to-many or many-to-many interactions. In particular, for the case of WSN there is a number of scenarios in which a node has to send the same data to multiple destinations. Given that sensor networks have very limited resources, multicasting is a very interesting approach to deliver the same data packet to...
An X-band SiGe-MMIC single-ended two-stage low noise amplifier (LNA) using low parasitic capacitance via holes for the emitter grounding is described. In order to obtain low impedance emitter/source ground of a silicon based single-ended amplifier, we have developed via holes which can be fabricated after the 0.35 mum SiGe-BiCMOS process. Since there are low resistivity epitaxial layers in the silicon...
This paper describes the new switching technique for the better performance mixer by utilizing the body terminal. The same phase LO signal is delivered to both the gate and body terminal simultaneously, leading to a closer ideal switching operation. The theoretical study of this operation is presented. Thanks to the body effect, the final circuit provides a conversion gain of 18 dB with 0 dBm LO power...
Data acquisition for low cost digital-controlled adaptive analog predistortion of a power amplifier is discussed. The predistorted amplifier has a RF input that is a UMTS signal comprising one or two adjacent carriers. The predistortion corrects for memoryless distortion. The data acquisition system measures the complex gain of the predistorted amplifier as a function of the input envelope, creating...
In this study, the finite-difference time-domain (FDTD) method is applied to simulate the through-wall-sensing (TWS) with ultra-wideband signals. Perfectly matched layer (PML) absorbing boundary conditions are used to absorb the outgoing wave. Scattering from two-dimensional (2D) metallic and dielectric cylinders for a 2D TE plane-incident wave are considered. In addition the scattering from targets...
This contribution analytically studies the influence of transmitter (TX) as well as receiver (RX) IQ mismatch on the performance of multiple-antenna OFDM systems based on direct-conversion. Analytical expressions are derived for the probability of error for MIMO OFDM systems in both nonfaded and Rayleigh faded channels. The results can be used to derive matching specifications for the TX- and RX-branches...
Power consumption is a key figure of merit for low data rate transceivers which are often used in autonomous battery operated devices. The use of forward error correction (FEC) schemes in such transceivers shall therefore not only be considered as a way to improve communication robustness but rather as a tradeoff between additional performance and power consumption overhead. In this paper, a selection...
In this paper we analyze and measure the distortion due to self-mixing of transmitter (TX) leakage in WCDMA mobile receivers (RX). The self-mixing is primarily due to the second order non linearity of the mixer, which is very significant in WCDMA receivers due to the high power of the TX leakage signal. Existing published work has analyzed the dependence of this distortion, on the TX leakage power...
This paper presents a crest factor reduction (CFR) technique compatible with polar-modulated signals for use in high efficiency polar transmitters. This technique processes only the amplitude signal of the polar-modulated signal, which reduces power consumption. In this implementation, the addition of the CFR technique to a polar transmitter consumes only 1% of the peak output power while increasing...
Direct digital synthesizers ICs using 0.25 mum InP HBT technologies with clock rates promise to extend the range of such devices to clock rates in excess of 30 GHz. In this work, we report progress towards this goal with the fabrication circuits with improved clock speed at 25 GHz with an approximate clock frequency/power consumption figure-of-merit of 2.5 GHz/W
Inter-carrier-interference (ICI) phenomena in the orthogonal frequency division multiplexing (OFDM) systems complicates the channel estimation and equalization tasks at the receiver side when the number of carriers increases, since the minimum mean squared error (MMSE) and zero forcing (ZF) criterions require non-trivial matrix inversion. The complexity can be reduced without strongly affecting the...
We describe ongoing research and product development focused on the theory, system design, and capacity gains from incorporating reverse link interference cancellation into commercial CDMA basestations. The work considers receiver architecture design tradeoffs, link cancellation efficiency in multipath fading channels, and the multi-cell network operation and performance
In this paper, we propose a light-weight and adaptive scheduling-based media access control protocol (LASMAC) for wireless sensor networks. Our primary goal is to achieve an energy-efficient and traffic-adaptive TDMA-based MAC protocol with low-overhead slot reservation. In our protocol, each node dynamically and flexibly assigns slots by exchanging information on the number of slots it wants to send...
Design and performance evaluation of a modified quadrifilar helix antenna (QHA) above various terrains are investigated utilizing the method of moments (MoM). In particular, antenna performance above "average ground" plane with epsivtau=13 and sigma=5 mS/m and "extremely poor" ground that is common to heavy industrial cities having epsivtau=3 and sigma=0.1 mS/m is first considered...
This paper proposes a novel high-gain millimeter-wave microstrip array antenna formed on a low temperature co-fired ceramic (LTCC) substrate. The proposed antenna employs alternately arranged parasitic elements formed on only two LTCC layers. This paper describes the design and characteristics of the proposed antenna. The antenna performance is also evaluated by electro-magnetic simulation. The proposed...
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