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The automatic generation of behavioral amplifier models based on the measurement of the input and output signals imply demanding requirements for the identification algorithm. In addition to the computational efficiency it is very important that such an algorithm needs only a low number of predefined parameters for the fitting process. To fulfil these requirements we suggest the use of a modified...
Barium strontium titanate (BST) varactors utilized in a VCO demonstrate unique tuning characteristics compared to junction varactors. A 2.7 GHz microstrip line VCO operates in a tracking phaselock loop configured as an X4 frequency multiplier. BST oscillator tuning and the effect on loop dynamics is observed by the intentional design of an under damped system. Oscillator noise correction and peaking...
This paper describes a method of enabling an over the air (terrestrial) digital television (DTV) system for Internet multimedia (IMS) and interactive television (ITV) service delivery to rural and remote areas. To this end a high speed return channel is proposed. Preliminary results of a laboratory evaluation on the return channel throughput at full bandwidth and power is presented. Measurement results...
Wireless mesh networks (WMNs) are evolving to be the key technology of the future. They aim to provide broadband wireless Internet service to a large community of users by exploiting multi-hop wireless communications between access points thus replacing wired infrastructure. However, in multi-hop networks, flows spanning multiple hops suffer from extremely low throughputs compared to flows traversing...
A high-linearity series-type Doherty amplifier that does not use bulky 3 dB quadrature hybrid coupler is developed for mobile handset applications. A predistorter is employed at the input to improve the ACPR performance at the high-power region, which effectively extends maximum linear power range. For size and stability considerations, the phasing circuits between the carrier and peak amplifiers...
Here, we present a method of locating near-field electromagnetic sources by estimating the parameters using the new C-SPRIT algorithm. A simple L-shape received antenna array is used for locating the sources of scattering signal from 3-D point of view where the distance (range), azimuth and elevation angles are the parameters of interest. The scattering sources are modeled as thin finite dipole antennas...
This paper illustrates the design of integrated EBG-antenna system using the transmission line approach. The approach is feasible using transverse EM (TEM) guide in HFSS (a finite element commercial solver), enabling fast and accurate designs. The effect of using single or multiple EBG cells on the radiation pattern is discussed. Designs featuring broadside to end fire radiations are addressed. Such...
The maximum achievable capacity of colocated multipoles is simulated and two practical mode-decoupled antennas with closely-coupled dipoles are proposed in this work. The concept of multipolar radiation leads to the design of mode-decoupled antennas. Because of the orthogonality property of radiation patterns between different antenna modes, not only the capacity can be maximized but also the excitation...
A dual-band RF front-end operating at 2.4 and 5.2 GHz is proposed. The dual-band RF front-end consists of a low noise amplifier and a single balance mixer which can be switched to operate at 2.4 and 5.2 GHz with the same hardware. In order to get the good performances at both frequency bands, the LNA uses a switched effective inductance in the input matching. The proposed RF front-end is designed...
Accurate indoor positioning with minimum dedicated infrastructure is required for certain critical applications such as emergency rescue, fire brigades or incident management. This paper presents an innovative TOA-based ranging technique for IEEE 802.11 networks, which is one of the essential steps towards achieving the desired location technique. Our approach is based on RTT measurements using standard...
This paper proposed a new asymmetrical microstrip stepped-impedance resonator (SIR) used for constructing a narrow band bandpass filter. With the proposed resonator, a desired bandpass response has been realized and a bandstop characteristic in the upper stopband has been obtained resulting in high spurious suppression. The size of the resonator is also reduced approximately 16 % when comparing with...
This paper presents implementation of some CDMA system compatible antenna array algorithms such as least mean square (LMS), constant modulus (CM) and space code correlator (SCC) on FPGA (such as Xilinx Virtex II Pro FPGA). Implementation issues such as architecture complexity and weight vector computation times are presented. For the signal modeling, cdma2000 reverse link signal model is considered...
Wireless ad hoc networks represent a powerful telecommunication infrastructure that is being exploited for enabling general wireless networking connectivity. However, a wide deployment of wireless ad hoc networks relies on system architectures able to provide energetic optimization, high channel utilization, support for real time traffic, etc. In such a context, recently a collision free MAC protocol...
Notice of Violation of IEEE Publication Principles"Fully-Integrated 0.13 μm CMOS Digital Low-IF DVB-S S2 Satellite TV Tuner Using a Discrete-Step AGC Loop"by Maxim, A.; Poorfard, R.; Johnson, R.; Crawley, P.; Kao, J.; Dong, Z.; Chennam, M.; Nutt, T.; Trager, D.;in the Proceedings of the 2007 IEEE Radio and Wireless Symposium,Jan. 2007 Page(s):67 - 70After careful and considered review, it...
A folded RF front-end with merged LNA and mixer is designed in 0.25 mum CMOS process for low power applications. The designed low power RF front-end uses the folded and current reuse techniques. It consumes 13.8 mW from 1.7 V supply voltage, while 5.2 dB NF and 25.7 dB conversion gain are achieved. By using PMOS in the switching stage of the folded mixer, low flicker noise of 7 dB at 10 kHz is also...
In this work we have reviewed and field tested several methods for power control in a MIMO-OFDM WLAN. We compared the performance of the independent waterfilling, multi-user waterfilling, and gradient projection techniques and quantified the impact of interference in an indoor environment. The results show the tradeoff between capacity and network overhead. Specifically, the gradient projection method...
Receiver space diversity based on millimeter-wave self-heterodyne transmission technique is demonstrated and its effective gain in two-path channel environments is theoretically and experimentally characterized. Under two-path channel environments, it is shown that the outputs of two receiver diversity modules have different amplitude but almost same phases without employing any millimeter-wave band...
This paper describes a novel magnetic communication system for wireless transmission operating at 14.9 MHz. A transmitter coil with 283 mA current value and three receivers coils located 1.8 m far from it are used to realize the overall design. The model is simulated by means of a commercial full wave electromagnetic tool based on the finite integration technique (FIT) implement in the frequency domain...
In our paper we present a comparison between multiband time-hopping impulse radio and multiband OFDM ultra wideband (UWB) systems. For the time-hopping impulse radio we consider the multiband time-hopping pulse amplitude modulation UWB system that uses Hadamard sequences to distribute power of a single information bit to all the available subbands. In the multiband OFDM UWB system we use interference...
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