Enabling location and environment awareness in cognitive radios

Celebi, Hasari; Arslan, Hüseyin

doi:10.1016/j.comcom.2008.01.006

Cited by 37 publications

(40 citation statements)

References 28 publications

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“…Then, the expression enclosed by square brackets in Equation (17), a symmetric N d k × N d k matrix, is defined as: (18) so that the cost function in Equation (17) can be restated as:…”

Section: Optimization Problem Statementmentioning

confidence: 99%

“…In the adaptation step, the radio switches to transmission and reception mode using its reconfigurability and reprogrammability property and tunes its operating parameters according to its best response strategy. Another emerging requirement for cognitive radios is location and environment awareness that involves modeling the capabilities of human beings and bats for realization of advanced and autonomous location and environment awareness features [18]. Adaptive positioning, determining the coordinates of a cognitive radio in space, is a step towards realization of accurate location awareness in cognitive radios.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive reconfigurable V-BLAST type equalizer for cognitive MIMO-OFDM radios

Ozden

2015

EURASIP J. Adv. Signal Process.

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An adaptive channel shortening equalizer design for multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) radio receivers is considered in this presentation. The proposed receiver has desirable features for cognitive and software defined radio implementations. It consists of two sections: MIMO decision feedback equalizer (MIMO-DFE) and adaptive multiple Viterbi detection. In MIMO-DFE section, a complete modified Gram-Schmidt orthogonalization of multichannel input data is accomplished using sequential processing multichannel Givens lattice stages, so that a Vertical Bell Laboratories Layered Space Time (V-BLAST) type MIMO-DFE is realized at the front-end section of the channel shortening equalizer. Matrix operations, a major bottleneck for receiver operations, are accordingly avoided, and only scalar operations are used. A highly modular and regular radio receiver architecture that has a suitable structure for digital signal processing (DSP) chip and field programable gate array (FPGA) implementations, which are important for software defined radio realizations, is achieved. The MIMO-DFE section of the proposed receiver can also be reconfigured for spectrum sensing and positioning functions, which are important tasks for cognitive radio applications. In connection with adaptive multiple Viterbi detection section, a systolic array implementation for each channel is performed so that a receiver architecture with high computational concurrency is attained. The total computational complexity is given in terms of equalizer and desired response filter lengths, alphabet size, and number of antennas. The performance of the proposed receiver is presented for two-channel case by means of mean squared error (MSE) and probability of error evaluations, which are conducted for time-invariant and time-variant channel conditions, orthogonal and nonorthogonal transmissions, and two different modulation schemes.

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“…Then, the expression enclosed by square brackets in Equation (17), a symmetric N d k × N d k matrix, is defined as: (18) so that the cost function in Equation (17) can be restated as:…”

Section: Optimization Problem Statementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adaptive reconfigurable V-BLAST type equalizer for cognitive MIMO-OFDM radios

Ozden

2015

EURASIP J. Adv. Signal Process.

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“…The length of T obs is assumed sufficiently longer than T s to account for the uncertainty on the actual value of τ and consider the noise outside the interval uncorrelated with the noise inside. We also assume that information on the interference spectral density S I (f ) is available from the spectrum awareness engine of a CR [4], [5].…”

Section: Signal Modelmentioning

confidence: 99%

“…so as to allow the dynamic reuse of the available spectrum [2]. The CR concept may also be applied in the context of high-definition location systems where the accuracy in ranging (hence, in localization) can be varied according to the available bandwidth (cognitive positioning systems) [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Performance Limits on Ranging with Cognitive Radio

Dardari

Karisan

Gezici

et al. 2009

2009 IEEE International Conference on Communications Workshops

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Abstract-Cognitive radio is a promising paradigm for efficient utilization of the radio spectrum due to its capability to sense environmental conditions and adapt its communication and localization features. In this paper, the theoretical limits on time-of-arrival estimation for cognitive radio localization systems are derived in the presence of interference. In addition, an optimal spectrum allocation strategy which provides the best ranging accuracy limits is proposed. The strategy accounts for the constraints from the sensed interference level as well as from the regulatory emission mask. Numerical results are presented to illustrate the improvements that can be achieved by the proposed approach.Index Terms-Ranging, time-of-arrival (TOA) estimation, cognitive radio, interference, ultra-wideband (UWB), orthogonal frequency division multiplexing (OFDM).

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“…It has been assumed that the signal delays for the different antennas are identical as this study involves a single-path case. According to (1) , and are key parameters to be estimated and can be expressed in vector form as = […”

Section: Cps Bandwidth Determination Signal Modelmentioning

confidence: 99%

Towards a bandwidth efficient cognitive positioning system

Thomas

Maharaj

2012

Electron. Lett.

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Presented is an efficient bandwidth determination model for the Cognitive Positioning System by utilising multiple receive antennas. The performance evaluations of the proposed multiple receive antenna positioning system were carried out using the linear least squares and maximum-likelihood location estimation techniques. The simulated results reveal that in a rural scenario, the 1×2 and 1×3 single-input-multiple-output (SIMO) cases display an average bandwidth efficiency with respect to positional accuracy, of 49% and 58% respectively, over the single-input-single-output (SISO) case. For an urban scenario, the 1×2 and 1×3 SIMO cases display a higher average bandwidth efficiency of 53% and 62% respectively over the SISO case.

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Enabling location and environment awareness in cognitive radios

Cited by 37 publications

References 28 publications

Adaptive reconfigurable V-BLAST type equalizer for cognitive MIMO-OFDM radios

Adaptive reconfigurable V-BLAST type equalizer for cognitive MIMO-OFDM radios

Performance Limits on Ranging with Cognitive Radio

Towards a bandwidth efficient cognitive positioning system

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