Results 121 to 130 of about 610 (179)
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Multicarrier modulation for HF communications
2016 International Conference on Military Communications and Information Systems (ICMCIS), 2016High-frequency (HF) communications can be flexibly realized using multicarrier modulation techniques. This paper compares the performance of three widely utilized MCM techniques, namely, orthogonal frequency-division multiplexing (OFDM), filter bank multicarrier/offset-QAM (FBMC/OQAM), and filtered multitone (FMT) in HF communications.
Juha Yli-Kaakinen +2 more
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IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 2000
A multicarrier quadrature amplitude modulation (QAM) modulator has been developed and implemented with programmable logic devices. The multicarrier QAM modulator contains four CORDIC-based QAM modulators. A conventional QAM modulator needs two multipliers, one adder, and sine/cosine ROM's.
J. Vankka +3 more
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A multicarrier quadrature amplitude modulation (QAM) modulator has been developed and implemented with programmable logic devices. The multicarrier QAM modulator contains four CORDIC-based QAM modulators. A conventional QAM modulator needs two multipliers, one adder, and sine/cosine ROM's.
J. Vankka +3 more
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Multicarrier Modulation and OFDM
2021The division of a frequency band into dedicated channels by modulation, called frequency-division multiplexing (FDM), has a long history. Prominent examples are the analog telephone networks until the 1970s. They were replaced by digital telephony, operating with time-division multiplex (TDM), in which dedicated time slot are allocated to each ...
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A multicarrier QAM modulator for WCDMA basestation
2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353), 2002A multicarrier QAM modulator for the wideband code division multiple access (WCDMA) basestation has been designed. The multicarrier modulator performs pulse shaping filtering for four baseband I and Q data streams. The filtered data is interpolated in three stages each interpolating with a factor of two.
Marko Kosunen +2 more
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Retransmission diversity schemes for multicarrier modulations
IEEE Transactions on Wireless Communications, 2006In this work, we present some simple techniques for enhancing the diversity provided by retransmissions in OFDM and DMT modulations. The primary techniques of interest are symbol interleaving and mapping diversity for retransmissions. Symbol interleaving involves retransmitting packet symbols through different subcarriers of the same channel, while ...
Harvind Samra, Zhi Ding 0001
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Proportionally Sampled Multicarrier Modulation
2008 IEEE International Conference on Communications, 2008A new proportionally sampled multicarrier modulation (PSMCM) system with optimum receiver is presented in this paper. By adopting different sampling rates at transmitter and receiver, the PSMCM system can achieve multipath diversity with simple linear operations.
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On multicarrier modulation for train-to-wayside communication
Proceedings of IEEE Vehicular Technology Conference (VTC), 2002Audio frequency train-to-wayside communication used in mass transit systems is subject to interference from harmonics of power and propulsion systems. The interference limits data rate in present modulation schemes. A multi-carrier modulation scheme, which offers higher data rate while ensuring orthogonality with interference, is presented. >
Prashant Thakore, Morton Kanefsky
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Orthogonal multicarrier modulations in satellite uplinks
International Journal of Satellite Communications and Networking, 2014SUMMARYIn this paper, we analyze Orthogonal Frequency‐Division Multiple Access and Single‐Carrier Frequency Division Multiple Access as alternative physical layer schemes for the up‐link of a satellite network. Both orthogonal frequency‐division multiple access and single‐carrier frequency division multiple access are orthogonal multicarrier ...
ROSATI, STEFANO +2 more
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Complex wavelet packets for multicarrier modulation
Proceedings of the 1998 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP '98 (Cat. No.98CH36181), 2002We first discuss two approaches for designing complex wavelet packets which can be used as orthogonal carriers for modulations like QAM and PM, and then compare the performance of the wavelet packet based modulation scheme with that of discrete multitone modulation using DFT bases.
Tushar K. Adhikary, Vellenki U. Reddy
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An introduction to multicarrier modulation
IEEE Potentials, 2000OFDM is a powerful modulation technique that increases bandwidth efficiency and simplifies the removal of distortion, due to a multipath channel. Advances in fast Fourier transform technology enable OFDM to be efficiently implemented in hardware, even for a large number of subbands.
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