Measurement of random time-variant linear channels

Bello, P.

doi:10.1109/tit.1969.1054332

Cited by 77 publications

(105 citation statements)

References 7 publications

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“…The V2V channel, in which both transmitter and receiver can be mobile, is a relatively newer area of study. Wireless channels can be modeled either deterministically, or statistically [5,6]. For most applications, deterministic modeling is site-specific and computationally intensive; hence, statistical models are often more attractive in that they do not attempt to provide exact estimation of a channel's small scale fading characteristics at points in space at any particular time; rather, they attempt to faithfully emulate the variation in these channel effects.…”

Section: V2v Channel Models Channel Parametersmentioning

confidence: 99%

“…We first provide a very brief review of some important parameters used to characterize wireless channels. (See [5,6] for a much more comprehensive review. )…”

Section: V2v Channel Models Channel Parametersmentioning

confidence: 99%

“…This description is also necessarily brief and incomplete, and interested readers are encouraged to see [5,6] for more comprehensive discussions.…”

Section: More On Statistical Channel Parametersmentioning

confidence: 99%

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Channel Modeling for Vehicle-To-Vehicle Communications

Matolak

2008

IEEE Commun. Mag.

147

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Section: V2v Channel Models Channel Parametersmentioning

confidence: 99%

“…We first provide a very brief review of some important parameters used to characterize wireless channels. (See [5,6] for a much more comprehensive review. )…”

Section: V2v Channel Models Channel Parametersmentioning

confidence: 99%

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Channel Modeling for Vehicle-To-Vehicle Communications

Matolak

2008

IEEE Commun. Mag.

147

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“…In practice, reliable channel estimation can be done in principle as long as the channel is underspread, i.e., [15], [16]. In our case, the multipath spread, is, at most, ( ) and the Doppler spread is approximately 133 Hz for a mobile speed of 50 mi/h and carrier frequency of 1.8 GHz.…”

Section: Simulation Resultsmentioning

confidence: 97%

“…Conditioned on the channel coefficients and 2 A pilot signal may be used to estimate these channel coefficients. This can be done in principle as long as the channel is underspread, i.e., B T < (1=2) [15], [16]. Most practical channels are underspread [1], [17], including the examples discussed in this paper.…”

Section: A Optimal Detectormentioning

confidence: 99%

Time-selective signaling and reception for communication over multipath fading channels

Bhashyam

Sayeed

Aazhang

2000

IEEE Trans. Commun.

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Abstract-The mobile wireless channel affords inherent diversity to combat the effects of fading. Existing code-division multiple-access systems, by virtue of spread-spectrum signaling and RAKE reception, exploit only part of the channel diversity via multipath combination. Moreover, their performance degrades under fast fading commonly encountered in mobile scenarios. In this paper, we develop new signaling and reception techniques that maximally exploit channel diversity via joint multipath-Doppler processing. Our approach is based on a canonical representation of the wireless channel, which leads to a time-frequency generalization of the RAKE receiver for diversity processing. Our signaling scheme facilitates joint multipath-Doppler diversity by spreading the symbol waveform beyond the intersymbol duration to make the channel time-selective. A variety of detection schemes are developed to account for the intersymbol interference (ISI) due to overlapping symbols. However, our results indicate that the effects of ISI are virtually negligible due to the excellent correlation properties of the pseudorandom codes. Performance analysis also shows that relatively small Doppler spreads can yield significant diversity gains. The inherently higher level of diversity achieved by time-selective signaling brings the fading channel closer to an additive white Gaussian noise channel, thereby facilitating the use of powerful existing coding techniques for Gaussian channels.

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Cellular Communications Channels

Mämmelä

Järvensivu

2003

Wiley Encyclopedia of Telecommunications

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Linear channel models for terrestrial outdoor mobile cellular systems including multipath fading and shadowing are summarized in this chapter. In microcells the cell radius is about 0.1 km to 1 km and in macrocells the cell radius is about 1 km to 30 km. Such systems typically work in the frequency range from about 1 GHz to 2 GHz. The bandwidth of the transmitted signals is in the order of 100 kHz to 1 MHz. The second order statistics of the typical Rayleigh fading wide‐sense stationary uncorrelated scattering (WSSUS) channel are described by the scattering function, which is the average power output as a function of the time delay and the Doppler shift parameter. The amplitudes of the multipath components can also be assumed to be Ricean or Nakagami‐m distributed. Shadowing is normally assumed to be lognormal. The results are generalized to the two‐dimensional case where the direction of arrival is included in addition to the delay. The channel impulse response is measured usually by using m‐sequences and correlation. Most practical channels are shown to be measurable. Measurements show that the the delay spreads in urban areas are from 1 ms to 2 ms and in mountainous areas from 100 ms to 150 ms. The Doppler spread depends on the carrier frequency and the velocity of the mobile station. Channel simulators are based on either stored channel impulse responses, ray tracing models or stochastic parametric models, and they are implemented by hardware or software by using transversal filters. Models are specified by different standardization organizations. At the end of the chapter recent trends are summarized, including larger carrier frequencies, increased bandwidths, three‐dimensional and nonstationary models, and models with multiple inputs and outputs.

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Measurement of random time-variant linear channels

Cited by 77 publications

References 7 publications

Channel Modeling for Vehicle-To-Vehicle Communications

Channel Modeling for Vehicle-To-Vehicle Communications

Time-selective signaling and reception for communication over multipath fading channels

Cellular Communications Channels

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