Partially coherent DS-SS performance in frequency selective multipath fading

Eng, Tan Chong; Milstein, L.B.

doi:10.1109/26.554293

Cited by 48 publications

(42 citation statements)

References 14 publications

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“…In order to simplify proceeding derivation steps, we further upper bound (72) as in (73) (which can be found at the top of the next page) ignoring the cross terms resulting from squaring the numerator of the Q function in (72). Under the assumption that phase estimate errors are sufficiently small for high PLL loop gain, the expectation of (73) with respect to ε can be approximated by replacing the terms cos(ε SD ) − cos(ε SD + θ Δ ) and cos(ε SRD ) − cos(ε SRD + θ Δ ) with their expected values [32], i.e., cos(ε SD ) − cos(ε SD + θ Δ ) ≈ (1 − cos(θ Δ )) E {cos(ε SD )} + sin(θ Δ )E {sin(ε SD )} where…”

Section: Appendix Cmentioning

confidence: 99%

Impact of imperfect channel estimation on the performance of amplify-and-forward relaying

Gedik¹,

Uysal

2009

IEEE Trans. Wireless Commun.

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Abstract-In this paper, we investigate the error rate performance of amplify-and-forward (AF) relaying with imperfect channel estimation. We consider a single-relay scenario with orthogonal and non-orthogonal AF (OAF and NAF) cooperative protocols. Two pilot-symbol-assisted receiver architectures are studied: In the mismatched-coherent receiver, the complex fading channel coefficients (i.e., both phase and amplitude) are estimated based on a linear minimum-mean-squared-error estimation approach and fed to a coherent sub-optimal maximum likelihood decoder as if the channels were perfectly known. In the partiallycoherent receiver, channel amplitude is ignored and phase is estimated by a phase locked loop. For both receiver types, we analyze the achievable diversity orders for cooperative protocols under consideration and quantify the impact of channel estimation through the derivation of pairwise error probability. Our performance analysis reveals that a second order diversity order is obtained for the considered single-relay scenario indicating that full diversity is extracted. Our simulation results demonstrate that the performance degradation due to channel estimation with respect to the genie bound (i.e., perfect channel state information) is as small as 1.1dB based on the employed detector. Performance results further show that partially-coherent receiver presents a similar performance to mismatched-receiver for sufficiently large loop SNRs although channel amplitude is completely ignored.

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Section: Appendix Cmentioning

confidence: 99%

Impact of imperfect channel estimation on the performance of amplify-and-forward relaying

Gedik¹,

Uysal

2009

IEEE Trans. Wireless Commun.

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“…Furthermore, it is assumed that the PLL SNR is much greater thanγ, whereγ = E b /N 0 is the average received SNR per bit. This assumption implies that the cosine of the phase estimate can be replaced by a deterministic variable (expected value) in the analysis [2]. This approximation technique is also referred to as linear approximation as it is exact when the function whose expectation is to be approximated is linear, regardless of the variance [2].…”

Section: System Modelmentioning

confidence: 98%

“…This assumption implies that the cosine of the phase estimate can be replaced by a deterministic variable (expected value) in the analysis [2]. This approximation technique is also referred to as linear approximation as it is exact when the function whose expectation is to be approximated is linear, regardless of the variance [2]. The received signal samples in baseband can be given asr i =|α i |e jφis i +ñ i , for i = 1, · · · , N wherẽ α n = |α n |e jφn represents a Nakagami-m distributed random variable,φ n represents the phase shift that is introduced by the fading channel,s i is the transmitted symbol andñ i are complex Gaussian random variables with zero mean and a variance of N 0 /2 in each dimension.…”

Section: System Modelmentioning

confidence: 99%

“…The phase estimation error φ c = φ −φ follows the Tikhonov distribution under the normal operating conditions, i.e., when the PLL's are in lock [2]. The Tikhonov PDF is given as [1] …”

Section: System Modelmentioning

confidence: 99%

“…In [1], it was shown that the phase error arising from a first-order phase locked loop (PLL) can be modeled by Tikhonov distribution, which is also a good approximation for second-order PLL when the signal-to-noise ratio (SNR) in the loop bandwidth is large. In [2], a bit error rate (BER) performance of direct sequence spread spectrum over a Rayleigh fading channel was presented using the Tikhonov probability density function (PDF). In [3], the error performance of binary phase shift keying (BPSK) with noisy phase reference having Tikhonov & Gaussian densities are analyzed in Nakagami-m fading channels.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Performance Analysis of a Partially Coherent System Using Constellation Rotation and Coordinate Interleaving

Kiyani

Weber

2008

IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference

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The performance analysis of a system employing coordinate interleaving and constellation rotation, over Nakagamim fading channels, in the presence of phase noise as well as additive white Gaussian noise (AWGN) is presented. The phase locked loop (PLL) dynamics result in phase noise thereby introducing imperfect receiver phase estimates which are assumed to have Tikhonov densities. The resulting performance degradation of the system due to the phase noise is analyzed and an upper bound for the average probability of bit error (P b ) for M -ary phase shift keying (M PSK) is presented. It is shown that in the presence of phase noise the optimum rotation angle does not change and that the upper bound is tight for high signal-to-noise ratios (SNR). Furthermore, we also show that a system employing coordinate interleaving and constellation rotation is more robust against phase estimation errors.

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The effect of Gaussian error in selection diversity combiners

Annamalai

2001

Wireless Communications

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Selection diversity combining (SDC) is one of the simplest and most commonly implemented diversity mechanism for mitigating the detrimental effects of deep fades experienced on wireless channels. While SDC improves the mean combined signal-to-noise ratio (SNR) over that of a single branch with increasing diversity order, its main advantage is the reduction of the probability of deep fades. The effect of Gaussian errors in the branch gain estimates on the SDC receiver performance is investigated by deriving new closed-form expressions for the probability density function, cumulative distribution function and the moment generating function of the combiner output SNR statistic. Mathematical expressions for quantifying the degradation in the mean combined SNR, outage probability and the average symbol error rate of a broad class of binary and multilevel modulation schemes owing to imperfect branch SNR estimates in Rayleigh fading are also derived. It is shown that combiner errors affect the mean combined SNR negligibly in comparison to their effect on the deep fades.

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Partially coherent DS-SS performance in frequency selective multipath fading

Cited by 48 publications

References 14 publications

Impact of imperfect channel estimation on the performance of amplify-and-forward relaying

Impact of imperfect channel estimation on the performance of amplify-and-forward relaying

Performance Analysis of a Partially Coherent System Using Constellation Rotation and Coordinate Interleaving

The effect of Gaussian error in selection diversity combiners

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