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Traditional OFDM based transmission system uses Cyclic Prefix (CP) in an OFDM symbol in order to maintain orthogonality of transmission. Present days' Ultra-Wideband (UWB) systems use Multi-Band OFDM (MB-OFDM) techniques for transmission in application like Wireless Personal Area Network (WPAN). UWB based systems are power limited by the regulation of FCC. CP introduces correlation in the transmitted...
Easy channel equalization for OFDM based UWB communications is considered to be one of its major advantages. Due to the format of transmission, the channel affects the signal only at discrete frequencies, and hence single-tap equalization is usually deemed sufficient. In this paper the selection of an efficient algorithm for equalization and its implementation is reported for indoor WPAN applications...
We present a fast converging scheme for estimating the coarse frequency offset in multi-band orthogonal frequency division multiplexing (MB-OFDM) based ultra-wideband (UWB) systems. Our estimator performs an averaging of initial estimate over multiple bands and shows an improved estimation of =3 times for band group 1 compared to our earlier proposed scheme. Cramer Rao lower bound (CRLB) on the estimation...
We present a fast converging scheme for estimating coarse frequency offset (FO) in multi-band orthogonal frequency division multiplexing (MB-OFDM) based ultra-wideband (UWB) systems for wireless personal area network (WPAN). Our estimator performs an averaging of initial estimate over multiple bands and shows an improved estimation of cong3 times in terms of estimation error variance for band group...
An Ultra-Wideband (UWB) channel exhibits frequency dependent delay characteristics in different bands of transmission. In [6] we studied and quantified the differences of delay parameters over frequency bands 3.1-4.6 GHz in several UWB channel models (CM). Based on this observation, we proposed an adaptive timing synchronization scheme (ATS) which estimates and maintains the timing delays of each...
This paper analyzes mathematically the crucial points of signal processing in a multi-band (MB) orthogonal frequency division multiplexing (OFDM) based system considering realistic ultra-wideband (UWB) channel environment. In the process of analysis, it emphasizes the significant aspects of UWB receiver design in comparison with a narrow-band system design. This is extended further with a frequency...
This work explores theoretically the unique aspects of different signal processing stages in a Multi-Band (MB) Orthogonal Frequency Division Multiplexing (OFDM) based system in realistic Ultra-Wideband (UWB) channel. In the process of analysis, it emphasizes the significant aspects of signal processing steps in UWB receiver design comparing a narrow-band system. The analysis preliminary considers...
The soft output Viterbi algorithm (SOVA) is used for data detection in indoor wireless channels representative of the JTC and wireless local area network (WLAN). The performance of SOVA-SOVA permutation as an equalizer followed by a decoder is evaluated by simulation experiment. The performance does not improve much for more than three iterations in these ISI channels. The results obtained for 1 dB...
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