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This paper presents the design of a reconfigurable Delta Sigma Analog to Digital Converter (ADC). Its main degree of liberty is the choice of the noise shaping among low pass and high pass. This reconfiguration parameter allows it to be adapted for both the Low-IF and the Zero-If receiver architectures. The ADC is GSM/UMTS compliant. It was designed in a 1.2 V 65 nm CMOS process. Electrical simulation...
A low-voltage 5th-order continuous-time ΣΔ modulator for a universal mobile TV receiver is presented. A unique feature of the proposed modulator is the blocker filtering provided using a 3rd order notch filter employing frequency dependent negative resistance (FDNR). The noise added by the FDNR is shaped. The modulator employs 3-level switched-capacitor DAC in the feedback. It has been implemented...
Current mode (CM) scheme provides suitable alternative for the high speed on-chip interconnect signaling. This paper presents a energy-delay optimization methodology for the current-mode (CM) signaling scheme. Optimization for the CM circuits for on-chip interconnects requires a joint optimization of driver and receiver device sizes, as their parameters which affect the energy-delay performance depend...
A detailed SNR (signal-to- noise ratio) analysis is given based on a proposed RF-interconnect model. The noise characteristics included ports reflecting noise, interlayer switching coupling noise and receiver thermal noise. To realize a good trade-off between bandwidth and BER (bit error ratio), a type of subsection modulation mode that synthesizes CDMA (code division multiple access) and MPSK (M-ary...
Some communication applications, like multimedia, deliver data of different importance classes allowing unequal error protection (UEP) levels. In this paper, a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM) is considered with a new UEP bit-loading algorithm based on the non-UEP algorithm by Chow, Cioffi, and Bingham. In the proposed bit-loading...
Three applications in wireless networks where model-free stochastic learning is applicable, are discussed. The learning based optimization problems are formulated and simulation results are presented. Some open issues are also discussed.
In this paper we discuss performance results of a novel real-time closed-loop power amplifier (PA) linearization technique that has originally been proposed by Ahmed and Li. The novel approach performs on-the-fly prediction and measurement of the PA AM/AM and AM/PM non-linearity, stores such non-linear characteristics and calculates their inverse functions in order to pre-distort the base-band amplitude...
In this paper, we propose a cross-layer optimization approach that exploits retransmission diversity in wireless CDMA communications. Conventionally, data packets that are not correctly detected are usually dropped. These dropped packets can be used to help data packet detection. By exploiting all the retransmitted packets, data packets can be correctly detected with higher probability. The proposed...
We designed and built a novel all-optical re-timing, re-amplifying, and re-shaping (3R) regeneration system based on terahertz optical asymmetric demultiplexers (TOADs) developed in our laboratory. The system is capable of parallel processing multiple wavelengths, a feature which will significantly improve the scalability of current wavelength division multiplexing (WDM) networks. Performance against...
Todaypsilas access network is migrating towards broadband IP, fixed/mobile convergence and service convergence. Thus, the next generation access network (NGAN) requires a converged optical/wireless access network infrastructure, other than the existing architecture that connect to the cellular, broadband wireless, and optical access networks separately, which complicate the network and increase the...
This paper addresses adaptive channel estimation for time-varying mobile wireless channels with nonstationary statistics. We presents a reduced complexity adaptive channel estimator based on a set membership filtering approach known as the Optimal Bounding Ellipsoid (OBE) algorithm. To exploit time and frequency domain correlation properties of the channel in an efficient low-complexity way, we allow...
Unequal error protection is the key to future transport of multimedia data. The paper presents an overview of some new approaches realizing UEP properties in physical transport, especially multicarrier modulation, or with LDPC and turbo codes. For multicarrier modulation, a UEP bit-loading method is described allowing for an arbitrary number of classes, arbitrary SNR margins between the classes and...
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