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A 53 dB gain limiting amplifier for OC-192 and 10 GbE applications is developed in a 50 GHz fT SiGe SOI complimentary bipolar process, and has 5 mV pk-pk sensitivity, 1.25 V pk-pk maximum input signal, 14 ps (20/80%) rise/fall times and 450 mV pk-pk output into matched differential 50 Ohm loads, consuming 430 mW on a 3.3 V supply. Input Cherry-Hooper gain stages limit the -3 dB bandwidth to 11 GHz...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H) which is required to operate under high mobility conditions resulting in significant Inter-Carrier Interference (ICI). Under these conditions, the conventional one-tap per subcarrier channel estimation and equalization is suboptimal since it does not account for ICI...
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 study bandwidth management of a wireless/optical based access/metro network in support of voice and data services. For voice services, we use a finite state Markov Chain to estimate the blocking probability of voice circuits over an Adaptive modulation and coding wireless channel, as a function of the channel parameters. For data services, we evaluate a rate matching and a buffer...
Optical communication systems based on dense wavelength division multiplexing (DWDM) would benefit from the ability to adjust the operating wavelength of a laser transmitter. Previous attempts, including thermal adjustment, etalon based wavelength locking, and various types of optical frequency and phase locked loops such as the Pound-Drever-Hall technique suffer from weaknesses including sensitivity...
Effects of improved channel estimation are studied for a proposed IEEE 802.11n OFDM MIMO system. Three channel estimation methods are considered: maximum likelihood (ML), time-domain truncation (TDT) and model-based (MB). TDT and MB are particularly useful when the channel delay spread is short. For an MMSE receiver, MB shows a 1-2.5 dB improvement over ML on the packet error rate performance for...
In this paper we investigate bounds on performance of joint parameter estimation and modulation classification. The Cramer-Rao Lower Bounds (CRLBs) of non-data aided joint estimates of signal amplitude and phase, and noise power are derived for binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals. In addition, an upper bound on performance of Quasi Hybrid Likelihood Ratio...
Fast Fourier Transform (FFT) is the most basic and essential part of Software Defined Radio (SDR). Therefore, designing regular, reconfigurable, modular and low hardware complexity FFT computation block is very important. A single FFT block should be configurable for varying length FFT computation and also for computation of different transforms like DCT, DST etc. In this paper, the authors analyze...
In this paper, we propose a cognitive radio-based multi-user resource allocation framework for mobile ad hoc networks using multi-carrier DS CDMA modulation over a frequency-selective fading channel. In particular, given pre-existing communications in the spectrum where the system is operating, in addition to potential narrow-band interference, a channel sensing and estimation mechanism is provided...
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