Capacity Bounds of Finite Dimensional CDMA Systems with Power Allocation, Fading, and Near-Far Effects

Kabir, P. K.; Shafinia, M. H.; Marvasti, Farokh

doi:10.1109/lcomm.2012.120312.121042

Cited by 8 publications

(11 citation statements)

References 13 publications

(32 reference statements)

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“…and Z 2,i is the Gaussian random variable with the meanũ i and varianceσ 2 i . In the next sub-section, we will prove that the PDF of Z 3,i can be well approximated as a Gaussian function.…”

Section: A Convolution Of Gaussian Function and Pdf Of Antenna Lossmentioning

confidence: 99%

“…Simulations cannot theoretically show the impacts of channel parameters on the PDF of path losses. In the third generation (3G) cellular communication systems, to avoid the near-far [2] [3] problem, path losses are fully compensated and the received power of the desired signal at the BS from all the UEs is the same. In Long Term Evolution (LTE) and LTE-Advanced systems, the fractional power control [1] partially compensates path losses and makes a good trade-off between the cell edge user throughput and cell throughput.…”

Section: Introductionmentioning

confidence: 99%

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Statistical Analysis of Path Losses for Sectorized Wireless Networks

Yan

Zhu

et al. 2017

IEEE Trans. Commun.

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In modern mobile communication networks, such as 3G and 4G networks, sectorized antennas have been widely used to divide each cell into multiple sectors in order to improve coverage, spectrum efficiency and quality of service. Large-scale path loss from a transmitting antenna to a receiving antenna should include (1) propagation attenuation that depends on transmission distance, (2) shadowing that depends on surrounding environment, and (3) antenna loss that depends on a sectorized antenna pattern and transmission angle. An in-depth analysis of statistical characteristics of large-scale path losses involving with these three factors is crucial for the design, operation, evaluation and optimization of modern sectorized wireless networks. In this paper, a sectorized antenna pattern is for the first time considered in the derivation of a closed-form expression of a probability density function (PDF) of large-scale path losses. Specifically, we first discover that the normalized PDF of propagation attenuation plus shadowing, which can be approximated by the Gaussian mixture model (GMM) with all system parameters, is fully determined by our newly-defined metric 10 ln 10 β σs , namely the attenuation exponent β to standard deviation of shadowing σs ratio (ASR). The convolution of GMM and antenna loss statistics is elaborately transformed to a series of differential equations. A closed-form PDF of large-scale path losses with sectorized antenna pattern can be obtained by solving these differential equations. To reduce the computational complexity, we further prove that the exciting sources of these differential equations can be tightly approximated by weighted Gaussian functions and, thus, the final solutions (i.e. PDF of path losses) can be derived in the form of Gaussian and Dawson functions. Our analytical results are verified by extensive numerical computation and Monte Carlo simulation results, e.g. the impact of ASR on the shape of PDF of propagation attenuation plus shadowing. Compared with traditional Gaussian-fitting approach, our newlyderived PDF of large-scale path losses with sectorized antenna patterns is at least two orders of magnitude more accurate in terms of Kullback-Leibler (KL) divergence under typical

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Section: A Convolution Of Gaussian Function and Pdf Of Antenna Lossmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Path Losses for Sectorized Wireless Networks

Yan

Zhu

et al. 2017

IEEE Trans. Commun.

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“…This is known as the near-far effect. In order to provide sufficient signal quality for all the users, the transmitter power have to be controlled which implies that the users must have sufficient Signal-to-Interference Ratios (SIRs) (Kabir et al, 2012).…”

Section: Power Control In Wcdmamentioning

confidence: 99%

A Fuzzy Logic Based Power Control for Wideband Code Division Multiple Access Wireless Networks

Norio¹

2012

Journal of Computer Science

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Problem statement:Resource management is one of the most important engineering issues in 3G systems where multiple traffic classes are supported each being characterized by its required Quality of Service (QoS) parameters. Call Admission Control (CAC) is one of the resource management functions, which regulates network access to ensure QoS provisioning. Efficient CAC is necessary for the QoS provisioning in WCDMA environment. The effective functioning of WCDMA systems is influenced by the power control utility. Approach: In this study, we propose to design a fuzzy logic based power control for Wideband Code Division Multiple Access Wireless Networks. This proposed technique is aimed at multiple services like voice, video and data for multiclass users. The fuzzy logic technique is used to estimate the optimal admissible users group inclusive of optimum transmitting power level. This technique reduces the interference level and call rejection rate. Results: By simulation results, we demonstrate that the proposed technique achieve reduced energy consumption for a cell with increased throughput. Conclusion: The proposed technique minimizes the power consumption and call rejection rate.

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“…To overcome this capacity hard limit, numerous UD [1][2][3][4][5][6][7][8][9][10][11][12][13][14], and non-UD [15][16][17][18][19] construction based systems have already been proposed. For the non-UD based approaches like O/O CDMA, PN/O CDMA [15], improved O/O CDMA [16], the maximisation in system capacity is achieved by collaborating two different sets of code (signature).…”

Section: Introductionmentioning

confidence: 99%