On-off frequency-shift keying for wideband fading channels
EURASIP Journal on Wireless Communications and Networking
Rapid Hybrid Acquisition of Ultra-Wideband Signals
Journal of VLSI Signal Processing Systems
On-off frequency-shift keying for wideband fading channels
EURASIP Journal on Wireless Communications and Networking
Editorial: signal processing for location estimation and tracking in wireless environments
EURASIP Journal on Advances in Signal Processing
On the capacity and energy efficiency of training-based transmissions over fading channels
IEEE Transactions on Information Theory
Optimal constellations for the low-SNR noncoherent MIMO block Rayleigh-fading channel
IEEE Transactions on Information Theory
Low-SNR capacity of noncoherent fading channels
IEEE Transactions on Information Theory
Error rate analysis for peaky signaling over fading channels
IEEE Transactions on Communications
Capacity bounds for peak-constrained multiantenna wideband channels
IEEE Transactions on Communications
Noncoherent capacity of underspread fading channels
IEEE Transactions on Information Theory
Wideband fading channel capacity with training and partial feedback
IEEE Transactions on Information Theory
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We show that very large bandwidths on fading multipath channels cannot be effectively utilized by spread-spectrum systems that (in a particular sense) spread the available power uniformly over both time and frequency. The approach is to express the input process as an expansion in an orthonormal set of functions each localized in time and frequency. The fourth moment of each coefficient in this expansion is then uniformly constrained. We show that such a constraint forces the mutual information to 0 inversely with increasing bandwidth. Simply constraining the second moment of these coefficients does not achieve this effect. The results suggest strongly that conventional direct-sequence code-division multiple-access (CDMA) systems do not scale well to extremely large bandwidths. To illustrate how the interplay between channel estimation and symbol detection affects capacity, we present results for a specific channel and CDMA signaling scheme