Effects of multiple-access interference on the noncoherent delay lock loop

Caffery, J.; Stuber, G.L.

doi:10.1109/26.891221

Cited by 26 publications

(14 citation statements)

References 25 publications

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“…Due to the longer spreading codes and the plenty of simultaneous inbound signal, the multiple access interference of inbound signal can be approximated as Gaussian noise [5,10] , and the equation of equivalent carrier-to-noise power ratio can expressed as [11,12] :…”

Section: A Multiuser Communication Performancementioning

confidence: 99%

Using Earth Station Time Synchronization System to Achieve Large-Capacity Communication under the Constraint of High-Precision Ranging

Chen

et al. 2012

2012 Second International Conference on Instrumentation, Measurement, Computer, Communication and Control

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The CDMA earth station time synchronization networks using GEO satellite transponder are based on TwoWay S atellite Time and Frequency Transfer. The spectrum of the ranging and communication signals is overlap, and each signal power is equal. As the effect of multiple access interference , the equivalent carrier to noise ratio of the earth station received signal is not linear growth with the increase of single signal transmission power, but exist a maximum. The maximum value of equivalent carrier to noise ratio of the received signal decreases when the number of earth station increases, which will reduce the ranging accuracy and increase the bit error rate, so the capacity of system communication reduced. To solve this problem, we propose a new method in the condition of fixed transponder ban dwidth. First, it uses the signal processing method of parallel interference cancellation in the receiver to suppress the multiple access interference. Second, in the as pect of the system design, under the premise of ensuring highranging accuracy, appropriately reducing the spreading code rate, and partially separating the spectrum of the ranging signals and communication signals. After separating the spectrum, the user number of each spectrum is half of the total user numbers. It reduces the multiple access interference of the received signal in each spectrum. It obtained the optimal spread code rate by analyzing in this paper. It only need eliminate the multiple access interference within a single spectrum after separate the spectrum. As the absence of eliminating the multiple access interference between two spectrums, comparing with directly using parallel interference cancellation, the received equivalent carrier to noise ratio decreased to less than 1dB after interference cancellation, while the computational complexity reduced to one-third of the original. earth station time synchronization; multiple-access interference; spectrum separation; interference cancellation

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Section: A Multiuser Communication Performancementioning

confidence: 99%

Using Earth Station Time Synchronization System to Achieve Large-Capacity Communication under the Constraint of High-Precision Ranging

Chen

et al. 2012

2012 Second International Conference on Instrumentation, Measurement, Computer, Communication and Control

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“…spreading sequences with Markovian sequences of λ = −2+ √ 3 reduces the phase tracking error. This result is explained qualitatively as follows: For a linearized DLL [1][2][3][4][5], the influence of MAI and channel noise to the phase tracking error is expressed by the following lowpass transfer function in the frequency domain:…”

Section: Stationary Moment Analysismentioning

confidence: 99%

“…Since the synchronization is one of nonlinear phenomena, the rigorous analysis of DLLs is difficult. In most of the preceding DLL analyses [1][2][3][4][5], small synchronization error allows DLLs to be linearized. Widely utilized spreading sequences such as Gold codes are regarded as independent and identically distributed (i.i.d.)…”

Section: Introductionmentioning

confidence: 99%

An analysis of delay-locked loop tracking binary Markovian sequence in the presence of multiple access interference and channel noise

Nagata

Fujisaka

Kamio

et al. 2011

NOLTA

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Abstract:This paper presents an analysis of delay-locked loops in direct spreading code division multiple access systems with Markovian spreading sequences. The established analysis with piecewise constant approximation is similar to the mean field analysis which estimates macroscopic characteristics of a spatially-distributed probabilistic system from the local interaction between the elements of the system with low computational complexity. The low complexity makes it possible to analyze the behavior of not only second-order archetype delaylocked loops but also higher-order non-coherent delay-locked loops in the presence of both multiple access interference and channel noise. It is found from the presented analysis that replacing i.i.d. spreading sequences with Markovian spreading sequences with non-vanishing negative autocorrelation reduces the phase tracking error of a non-coherent 1Δ delay-locked loop. The time spent for estimating the error by the presented method is about 1/1000 compared with that by the path integral method.

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“…The performance analyses of the DLL have been investigated for additive white Gaussian noise (AWGN) channels [1]- [3] during the past three decades. However, the DLL performance is degraded seriously in the presence of a Doppler shift [4], multiple-access interference (MAI) [5], and multipath fading [6]. The primary reason why the Nakagami-m fading channel is getting more popular lies in its good fit for empirical data in land-mobile and indoor-mobile radio communications [7], [8].…”

Section: Introductionmentioning

confidence: 99%

Statistical Analyses of Digital Delay-Lock Loops Over Nakagami-m Fading Channels

Tsai

2006

IEEE Vehicular Technology Conference

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Statistical analyses of a non-coherent digital delaylock loop (DDLL) for direct-sequence spread-spectrum signals over Nakagami-m fading channels are discussed. Analytical expressions to the characteristics, such as Cramér-Rao lower bound (CRLB), of the timing tracking errors have been proposed based upon the timing error probability density function (PDF) of the Chapman-Kolmogorov (C-K) equation of the first-and second-order loops. Furthermore, mean square tracking errors (MSTEs) against distinct parameters are also simulated, while their corresponding numerical results with CRLBs are confirmed by time-domain computer calculations.

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Effects of multiple-access interference on the noncoherent delay lock loop

Cited by 26 publications

References 25 publications

Using Earth Station Time Synchronization System to Achieve Large-Capacity Communication under the Constraint of High-Precision Ranging

Using Earth Station Time Synchronization System to Achieve Large-Capacity Communication under the Constraint of High-Precision Ranging

An analysis of delay-locked loop tracking binary Markovian sequence in the presence of multiple access interference and channel noise

Statistical Analyses of Digital Delay-Lock Loops Over Nakagami-m Fading Channels

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