Issues of the Simulation of Wireless Channels with Exponential-Decay Power-Delay Profl es

Gutiérrez, Carlos; Cabrera, M.

doi:10.1109/pimrc.2005.1651488

Cited by 7 publications

(8 citation statements)

References 4 publications

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“…Where  n is the n th delay and these delays are chosen to be fixed and equally spaced such that  n =30n ns, N c is the number of taps and is chosen that N c =21 taps, this gives a maximum path delay  max =600 ns. The coefficients c n are complex Gaussian samples, each has a Jakes Doppler spectrum with an exponential power profile [15]…”

Section: Simulation Resultsmentioning

confidence: 99%

“…The PHYDYAS filter has a special feature regarding its implementation which is that the shaping can be made in the frequency domain i.e., before the IFFT operation by convolving the set of coefficients b k with the modulating symbols and then applying to the IFFT. However, that would require KM points IFFT [9] instead of M point IFFT in case of the polyphase network (PPN) implementation for the shaping filter as is the case for the other types of shaping filters [15].…”

Section: B Phydyasmentioning

confidence: 99%

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Comparative Study of Pulse Shaping Filters in FBMC

2019

IJCCCE

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Filter Bank Multicarrier (FBMC) is a multitone modulation technique that is expected to replace the Orthogonal Frequency Division Multiplexing (OFDM) due to its inherent characteristics that makes it immune to channel dispersive effect on the transmitted signal in both time and frequency. The most effective ingredient in the FBMC is the pulse shaping that the OFDM symbol lacks. In this paper, a comparative study is presented between different pulse shapes used in the FBMC like the RRC, PHYDIAS, IOTA and Hermite function alongside the conventional OFDM.

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Section: Simulation Resultsmentioning

confidence: 99%

Section: B Phydyasmentioning

confidence: 99%

Comparative Study of Pulse Shaping Filters in FBMC

2019

IJCCCE

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“…It is the most commonly accepted PDP model for indoor channels in accordance with theory and experimental data [26]. When the maximum excess delay .L 1/T is large enough compared with , the FCF of the channel model, obtained by Fourier transform of the PDP, is accurately approximated by [27]…”

Section: Correlated Channel Modelmentioning

confidence: 88%

Spreading code allocation strategy for downlink multicarrier code division multiple access transmission in a correlated Rayleigh fading channel

Garnier

Delignon

Ghazi

et al. 2012

Wirel. Commun. Mob. Comput.

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In this paper, we address the problem of multiple access interference (MAI) in a downlink multicarrier code division multiple access system. Because in the realistic case of correlated faded subcarriers, MAI greatly depends on the codes assigned to users, one way of improving performance without increasing receiver complexity consists in an appropriate code selection. We propose a code allocation strategy with the following properties: possible use with any code sequence and equalizer, low complexity, and efficient management of load variations. The allocation problem is formulated as a minimization problem of a cost function related to MAI. First, we provide analytical expressions for the channel frequency correlation function after maximum ratio combining, equal gain combining, and minimum mean square error equalization and for the MAI power. Then, by approximating these expressions, we define a simple cost function and build an iterative algorithm on the basis of the minimum maximum criterion to select the spreading codes. Finally, a complete analysis of the allocation efficiency is provided versus key parameters, in particular, the degree of correlation between the faded subcarriers, the system load, and the equalization techniques.

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“…Nonetheless, the results reported in [21] suggest that the pertinence of such TDL models is rather doubtful when the concept is applied to WSSUS channels. In fact, the answer to the question whether SSTDL models are suitable for modeling WSSUS channels is still lacking in the literature.…”

Section: Several Sms Basing On the Time-variant Tapped-delay-line (Tdmentioning

confidence: 99%

On the problems of symbol‐spaced tapped‐delay‐line models for WSSUS channels

Guti

Cabrera-Bean

Pätzold

2008

Wireless Communications

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This paper analyzes the pertinence and statistical behavior of symbol-spaced tappeddelay-line (SSTDL) models for wide-sense stationary uncorrelated scattering (WSSUS) mobile radio channels. SSTDL models are obtained by sampling the channel impulse response (CIR) in delay domain at a rate equal to the reciprocal of the symbol duration. They were proposed more than four decades ago as canonical channel models for band-limited time-variant linear systems, and are nowadays widely in use for assessing the performance of several wireless communication systems. The applicability of these tapped-delay-line (TDL) models seems to be unquestionable, as they were developed in the framework of the sampling theorem. Nonetheless, we show here that SSTDL models should be used with care to model WSSUS channels, because the channel's uncorrelated scattering (US) condition might easily be violated. Furthermore, we show that SSTDL models suffer from strong limitations in emulating the channel frequency correlation function (FCF). This drawback leads to an inaccurate performance evaluation of wireless communication systems sensitive to the FCF. To cope with this problem, we present a simple solution by doubling the channel's sampling rate. The benefits of this solution are demonstrated with some exemplary simulation results.

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Issues of the Simulation of Wireless Channels with Exponential-Decay Power-Delay Profl es

Cited by 7 publications

References 4 publications

Comparative Study of Pulse Shaping Filters in FBMC

Comparative Study of Pulse Shaping Filters in FBMC

Spreading code allocation strategy for downlink multicarrier code division multiple access transmission in a correlated Rayleigh fading channel

On the problems of symbol‐spaced tapped‐delay‐line models for WSSUS channels

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