Intelligent antennas for wireless communications-uplink

Buehrer, R. Michael; Kogiantis, Achilles; Liu, Shang-chieh; Tsai, Jiann-An; Uptegrove, Dirck

doi:10.1002/bltj.2180

Cited by 21 publications

(10 citation statements)

References 20 publications

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“…Results in the figure indicate that the use of a 4-branch antenna allows capacity to be doubled relative to 2 branches, and adaptive antenna processing on 4 branches allows 50% more voice users to be supported versus conventional maximum ratio combining (MRC). These and other techniques for intelligent antenna processing in the reverse link, or uplink, are described in detail in a recent Bell Labs Technical Journal paper by Buehrer et al 31 The basic mechanisms for improving the forward link, or downlink, are transmit diversity and spatial beam forming. These can also be deployed in combination.…”

Section: Interference Mitigation and Capacity Improvement Techniquesmentioning

confidence: 98%

Technology evolution for mobile and personal communications

Zysman

Tarallo

Howard³

et al. 2002

Bell Labs Tech. J.

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Section: Interference Mitigation and Capacity Improvement Techniquesmentioning

confidence: 98%

Technology evolution for mobile and personal communications

Zysman

Tarallo

Howard³

et al. 2002

Bell Labs Tech. J.

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“…These weights depend on the optimization criterion, for example, maximizing the received signal energy (equivalent to SNR), maximizing the SINR, and minimizing the mean squared error between the received signal and some reference signal to be known at the base station [4]. Equation (6) can be rewritten with (1), (3) and either (4) or (5) tô…”

Section: Signal Modelmentioning

confidence: 99%

“…The angular spread of the individual incoming resolvable paths determines the amount of spatial fading seen at an antenna array [4] and the size of the array employed will affect the coherence of the array output signals as well as which detection algorithms are applicable. For the rest of this paper, we assume closely spaced antenna elements yielding highly spatially correlated signals at the array elements.…”

Section: Signal Modelmentioning

confidence: 99%

“…Since both covariance matrices are positive definite, the maximum SIR criterion is satisfied when the weight vector equals the principal eigenvector of the matrix pair associated with the largest eigenvalue [4,13,21], that is,…”

Section: Downlink Beamformingmentioning

confidence: 99%

“…In such a setting, transmit beamforming at base stations provides a powerful method for increasing downlink capacity [3,4,5,6]. But, full exploitation of the spatial properties of the downlink channel requires meaningful transmit channel information at the base station.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

System-Level Performance of Antenna Arrays in CDMA-Based Cellular Mobile Radio Systems

Czylwik

Dekorsy²

2004

EURASIP J. Adv. Signal Process.

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Smart antennas exploit the inherent spatial diversity of the mobile radio channel, provide an antenna gain, and also enable spatial interference suppression leading to reduced intracell as well as intercell interference. Especially, for the downlink of future CDMA-based mobile communications systems, transmit beamforming is seen as a well-promising smart antenna technique. The main objective of this paper is to study the performance of diverse antenna array topologies when applied for transmit beamforming in the downlink of CDMA-based networks. In this paper, we focus on uniform linear array (ULA) and uniform circular array (UCA) topologies. For the ULA, we consider three-sector base stations with one linear array per sector. While recent research on downlink beamforming is often restricted to one single cell, this study takes into account the important impact of intercell interference on the performance by evaluating complete networks. Especially, from the operator perspective, system capacity and system coverage are very essential parameters of a cellular system so that there is a clear necessity of intensive system level investigations. Apart from delivering assessments on the performance of the diverse antenna array topologies, in the paper also different antenna array parameters, such as element spacing and beamwidth of the sector antennas, are optimized. Although we focus on the network level, fast channel fluctuations are taken into account by including them analytically into the signal-to-interference calculation.

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Functional characterization of human sphingosine kinase‐1

et al. 2000

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Sphingosine kinase catalyzes the phosphorylation of sphingosine to form sphingosine 1-phosphate (SPP), a novel lipid mediator with both intra-and extracellular functions. Based on sequence identity to murine sphingosine kinase (mSPHK1a), we cloned and characterized the first human sphingosine kinase (hSPHK1). The open reading frame of hSPHK1 encodes a 384 amino acid protein with 85% identity and 92% similarity to mSPHK1a at the amino acid level. Similar to mSPHK1a, when HEK293 cells were transfected with hSPHK1, there were marked increases in sphingosine kinase activity resulting in elevated SPP levels. hSPHK1 also specifically phosphorylated D-erythro-sphingosine and to a lesser extent sphinganine, but not other lipids, such as D,L-threo-dihydrosphingosine, N,N-dimethylsphingosine, diacylglycerol, ceramide, or phosphatidylinositol. Northern analysis revealed that hSPHK1 was widely expressed with highest levels in adult liver, kidney, heart and skeletal muscle. Thus, hSPHK1 belongs to a highly conserved unique lipid kinase family that regulates diverse biological functions.z 2000 Federation of European Biochemical Societies.

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Intelligent antennas for wireless communications-uplink

Cited by 21 publications

References 20 publications

Technology evolution for mobile and personal communications

Technology evolution for mobile and personal communications

System-Level Performance of Antenna Arrays in CDMA-Based Cellular Mobile Radio Systems

Functional characterization of human sphingosine kinase‐1

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