Statistical analysis of multiple access interference in Rayleigh fading environment for MIMO CDMA systems

Kazemzad, Mahmood; Asad, Syed Muhammad; Moinuddin, Muhammad; Zerguine, Azzedine; Paul, Shashi

doi:10.1109/ssp.2014.6884663

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…. The statistical characterization (variance) of MIMO CDMA MAI and noise is given in [7]. The MIMO CDMA MAI is given by…”

Section: Motivationmentioning

confidence: 99%

MAI and Noise Constrained LMS Algorithm for MIMO CDMA Linear Equalizer

Kazemzad¹,

Asad²,

Moinuddin³

et al. 2016

ijacsa

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Abstract-This paper presents a constrained least mean squared (LMS) algorithm for MIMO CDMA linear equalizer is presented, which is constrained on spreading sequence length, number of subscribers, variances of the Gaussian noise and the multiple access interference (MAI) plus the additive noise (introduced as a new constraint). The novelty of the proposed algorithm is that MAI and MAI plus noise variance has never been used as a constraint in MIMO CDMA systems. Convergence analysis is performed for the proposed algorithm in case when statistics of MAI and MAI plus noise are available. Simulation results are presented to compare the performance of the proposed constrained algorithm with other constrained algorithms and it is proved that the new algorithm has outperformed the existing constrained algorithms. presented an algorithm (Noise-constrained LMS) for identification and tracking of finite impulse response (FIR) channels using the variance of the receiver noise. An advantage of the noise constrained least mean squared (NCLMS) is that it outperforms the LMS algorithm while keeping the same computational complexity. A complementary pair LMS (CP-LMS) [3] was initiated by using constrained optimization technique named augmented Lagrangian (AL) which can be utilized to solve the problem of selecting an appropriate update step-size in LMS algorithm. This technique was utilized in [4], in which the knowledge of the variance of MAI plus noise was incorporated to develop what is called the constrained LMS algorithm (MNCLMS) for CDMA systems.Since MAI and the additive white Gaussian noise (AWGN) effect performance of CDMA multi user, multi-antenna environment, it is imperative to design a receiver architecture which will negate the effect of MAI and additive noise. This requires a MIMO implementation of the MNCLMS algorithm presented in [4]. The proposed constrained algorithm is developed by incorporating MIMO MAI and noise variances thus resulting in a generalized MIMO MAI plus noise constrained LMS (MIMO-MNCLMS) adaptive algorithm. As it is

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“…. The statistical characterization (variance) of MIMO CDMA MAI and noise is given in [7]. The MIMO CDMA MAI is given by…”

Section: Motivationmentioning

confidence: 99%

MAI and Noise Constrained LMS Algorithm for MIMO CDMA Linear Equalizer

Kazemzad¹,

Asad²,

Moinuddin³

et al. 2016

ijacsa

Self Cite

View full text Add to dashboard Cite

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“…Consequently, explicit closed-form expressions for both the PDFs of MAI and MAI plus noise were derived for a Rayleigh fading channel. Recently in [22], the approach of [16] was used to analyze the MAI in MIMO-CDMA systems which was later used in [23] to design minimum mean-square-error (MMSE) estimate of fading channels in the presence of MIMO systems. Although, the work in [22] has provided the derivation for the MAI statistics and the work in [23] has provided MMSE estimator design based on this statistics, but there can be many other interesting applications of the derived MAI statistics in practical scenarios which these work failed to provide.…”

Section: Introductionmentioning

confidence: 99%

Multiple access interference in MIMO-CDMA systems under Rayleigh fading: statistical characterization and applications

Kazemzad

Asad

Moinuddin

et al. 2016

EURASIP J. Adv. Signal Process.

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A major limiting factor in the performance of multiple-input-multiple-output (MIMO) code division multiple access (CDMA) systems is multiple access interference (MAI) which can reduce the system's capacity and increase its bit error rate (BER). Thus, a statistical characterization of the MAI is vital in analyzing the performance of such systems. Since the statistical analysis of MAI in MIMO-CDMA systems is quite involved, especially when these systems are fading, existing works in the literature, such as successive interference cancellation (SIC) or parallel interference cancellation (PIC), employ suboptimal approaches to detect the subscriber without involving the need for MAI statistics. The knowledge of both MAI and noise statistics plays a vital role in various applications such as the design of an optimum receiver based on maximum likelihood (ML) detection, evaluation of the probability of bit error, calculation of the system's capacity, evaluation of the outage probability, estimation of the channel's impulse response using methods including the minimum mean-square-error (MMSE), the maximum likelihood(ML), and the maximum a posteriori probability (MAP) criterion. To the best of our knowledge, there is no existing work that explicitly evaluates the statistics of the MAI-plus-noise in MIMO fading channels. This constitutes the prime objective of our proposed study here. In this work, we derive the expressions for the probability density function (PDF) of MAI and MAI-plus-noise in MIMO-CDMA systems in the presence of both Rayleigh fading channels and additive white Gaussian noise. Moreover, we evaluate the probability of the bit error rate in the presence of optimum reception using a ML receiver. Our theoretical findings can provide a reliable basis for both system design and various performance analyses of such systems. Our simulation results show that the theoretical findings are very well substantiated.

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Rayleigh fading channel estimation using MMSE estimator for MIMO-CDMA system

Kazemzad

Asad

Saeed

et al. 2015

2015 International Conference on Communications, Signal Processing, and Their Applications (ICCSPA'15)

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In this paper, we are proposing a pilot-aided channel estimator for the multiple-input multiple-output (MIMO) directsequence code-division multiple access (DS-CDMA) communication systems based on the minimum mean-square error (MMSE) estimate of the attenuated transmitted signals in the presence of Rayleigh fading channel coupled with the white Gaussian noise. The proposed receiver consists of bank of matched filters matched to the signature waveform of the desired user followed by a nonlinear estimator, resulting from the MMSE estimate of the attenuated transmitted signal. Simulation results carried out for multiple values of signal to noise ratio (SNR) and number of users show that the theoretical predictions are very well substantiated.

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Statistical analysis of multiple access interference in Rayleigh fading environment for MIMO CDMA systems

Cited by 5 publications

References 7 publications

MAI and Noise Constrained LMS Algorithm for MIMO CDMA Linear Equalizer

MAI and Noise Constrained LMS Algorithm for MIMO CDMA Linear Equalizer

Multiple access interference in MIMO-CDMA systems under Rayleigh fading: statistical characterization and applications

Rayleigh fading channel estimation using MMSE estimator for MIMO-CDMA system

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