Journal ArticleDOI
Fading channel communications
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TLDR
Two radio propagation channels for beyond-the-horizon communications, troposcatter, and HF are currently being reexamined with renewed interest in the use of high frequency (HF) and Troposcatter communications for networks carrying digital traffic.Abstract:
Adaptive processing can reduce the effects of fading on beyond-the-horizon digital radio links. Two radio propagation channels for beyond-thehorizon communications, troposcatter, and HF are currently being reexamined. In the past, transmission over these radio channels had been considered unreliable due to fading effects. Recently, conversion from analog to digital transmission and the use of new adaptive signal processing techniques have offered promise of acceptable network communication quality. In addition, over-the-horizon radio provides economic and/or secu-· rity advantages relative to satellite, cable, or line-of-sight terrestrial microwave links. There is renewed interest in . the use of high frequency (HF) and troposcatter communications for networks carrying digital traffic.read more
Citations
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Journal ArticleDOI
A new approach to multipath correction of constant modulus signals
J. Treichler,B. Agee +1 more
TL;DR: In this article, an adaptive digital filtering algorithm that can compensate for both frequency-selective multipath and interference on constant envelope modulated signals is presented, which exploits the fact that multipath reception and various interference sources generate incidental amplitude modulation on the received signal.
Journal ArticleDOI
The Origins of Spread-Spectrum Communications
TL;DR: The WHYN, Hush-Up, BLADES, F9C-A/Rake, CODORAC, and ARC-50 systems are featured, along with a description of the prior art in secure communications, and introductions to other early spreadspectrum communication efforts.
Patent
RAKE receiver with selective ray combining
TL;DR: The WRAKE receiver as discussed by the authors is a modified RAKE receiver for CDMA communications that includes a receiver for receiving and demodulating a composite signal of overlapping transmitted signals (spread signals), a sampler to sample the received signals, a selector for selecting different groups of samples, a correlator for correlating the samples with known despreading codes and a comparator to determine the symbol transmitted.
Patent
Quantized coherent rake receiver
TL;DR: In this paper, an implementation of coherent diversity combining in a RAKE receiver that uses energy in signal echoes by integrating information from main-path and bit-period-delayed signal propagation paths to remove echo distortion, or time dispersion, is described.
Patent
Multiple access coding for radio communications
TL;DR: In this article, a two-tier ciphering scheme was proposed to ensure security at the cellular system level by using a pseudorandomly generated code key to select one of the scrambling masks common to all of the mobile stations in a particular cell.
References
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Book
Dynamic Programming
TL;DR: The more the authors study the information processing aspects of the mind, the more perplexed and impressed they become, and it will be a very long time before they understand these processes sufficiently to reproduce them.
Journal ArticleDOI
Maximum-likelihood sequence estimation of digital sequences in the presence of intersymbol interference
TL;DR: In this paper, a maximum likelihood sequence estimator for a digital pulse-amplitude-modulated sequence in the presence of finite intersymbol interference and white Gaussian noise is developed, which comprises a sampled linear filter, called a whitened matched filter, and a recursive nonlinear processor, called the Viterbi algorithm.
Journal ArticleDOI
Characterization of Randomly Time-Variant Linear Channels
TL;DR: Several new canonical channel models are derived in this paper, some of which are dual to those of Kailath, and a model called the Quasi-WSSUS channel is presented to model the behavior of such channels.
Journal ArticleDOI
A Communication Technique for Multipath Channels
R. Price,P. E. Green +1 more
TL;DR: Application of principles of statistical communication theory has led to a new communication system, called Rake, designed expressly to work against the combination of random multipath and additive noise disturbances, which indicate that such systems have certain optimal properties.