Wideband Sequential Spectrum Sensing with Varying Thresholds

Haghighi, Kasra; Svensson, Arne; Agrell, Erik

doi:10.1109/glocom.2010.5683988

Cited by 12 publications

(7 citation statements)

References 21 publications

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“…Thus, a CR which can optimally incorporate all previous observations and thus decides for transmission within a short time is appealing. Sequential spectrum sensing has been proven to be on average faster than traditional energy detection [7], [15]- [17]. However, since detection time varies in sequential detection, it is not a good candidate for slotted CR strategy.…”

Section: Introductionmentioning

confidence: 99%

On Optimum Causal Cognitive Spectrum Reutilization Strategy

Haghighi

Ström

Agrell

2012

IEEE J. Select. Areas Commun.

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In this paper we study opportunistic transmission strategies for cognitive radios (CR) in which causal noisy observation from a primary user(s) (PU) state is available. PU is assumed to be operating in a slotted manner, according to a two-state Markov model. The objective is to maximize utilization ratio (UR), i.e., relative number of the PU-idle slots that are used by CR, subject to interference ratio (IR), i.e., relative number of the PU-active slots that are used by CR, below a certain level. We introduce an a-posteriori LLR-based cognitive transmission strategy and show that this strategy is optimum in the sense of maximizing UR given a certain maximum allowed IR. Two methods for calculating threshold for this strategy in practical situations are presented. One of them performs well in higher SNRs but might have too large IR at low SNRs and low PU activity levels, and the other is proven to never violate the allowed IR at the price of a reduced UR. In addition, an upper-bound for the UR of any CR strategy operating in the presence of Markovian PU is presented. Simulation results have shown a more than 116% improvement in UR at SNR of −3dB and IR level of 10% with PU state estimation. Thus, this opportunistic CR mechanism possesses a high potential in practical scenarios in which there exists no information about true states of PU.

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Section: Introductionmentioning

confidence: 99%

On Optimum Causal Cognitive Spectrum Reutilization Strategy

Haghighi

Ström

Agrell

2012

IEEE J. Select. Areas Commun.

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“…Hence (21) can be rewritten as (23) The level-triggered sampling procedure at each secondary user is summarized in Algorithm 1. Until the fusion center terminates it, the algorithm produces the bit stream based on the local cumulative LLR values at time instants , and sends these bits to the fusion center instantaneously as they are generated.…”

Section: A Uniform Level-triggered Sampling At Each Sumentioning

confidence: 99%

Cooperative Sequential Spectrum Sensing Based on Level-Triggered Sampling

Yılmaz

Moustakides

Wang

2012

IEEE Trans. Signal Process.

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We propose a new framework for cooperative spectrum sensing in cognitive radio networks, that is based on a novel class of nonuniform samplers, called the event-triggered samplers, and sequential detection. In the proposed scheme, each secondary user (SU) computes its local sensing decision statistic based on its own channel output; and whenever such decision statistic crosses certain predefined threshold values, the secondary user will send one (or several) bit of information to the fusion center (FC). The FC asynchronously receives the bits from different SUs and updates the global sensing decision statistic to perform a sequential probability ratio test (SPRT), to reach a sensing decision. We provide an asymptotic analysis for the above scheme, and under different conditions, we compare it against the cooperative sensing scheme that is based on traditional uniform sampling and sequential detection. Simulation results show that the proposed scheme, using even 1 bit, can outperform its uniform sampling counterpart that uses infinite number of bits under changing target error probabilities, SNR values, and number of SUs.Index Terms-Asymptotic optimality, cognitive radio, decentralized detection, event-triggered sampling, randomized quantization, sequential probability ratio test (SPRT).

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“…At the current stage, we have intentionally limited the research to the ED case. In particular, we concentrated on its pragmatic and sequential version, called SEND (Sequential Energy Detection), implemented on USRP N210 boards in [6], [7]. The rationale behind this algorithm is as follows: the SEND algorithm stops working at the latest stage after the collection of N samples, as the traditional ED algorithm.…”

Section: Introductionmentioning

confidence: 99%

The impact of hardware implementation on the performance of spectrum sensing algorithms

Cichoń

Kliks

2014

2014 11th International Symposium on Wireless Communications Systems (ISWCS)

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The problem of efficient hardware implementation of a reliable spectrum sensing method is crucial for the practical realization of the cognitive radio terminal. This paper analyses the influence of various hardware implementation issues on the performance of the sequential energy-detection-based spectrum sensing algorithm. In particular, the necessity of noise inclusion in noise variance estimation is discussed. Furthermore, based on the experiments conducted with the USRP N210 board used for the detection of a wireless microphone, the impact of numerous unwanted phenomena on the reliability of the spectrum sensing algorithm is also presented. It has been stated that such effects can influence not only noise-power dependent methods, but also the algorithms of other classes.

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Wideband Sequential Spectrum Sensing with Varying Thresholds

Cited by 12 publications

References 21 publications

On Optimum Causal Cognitive Spectrum Reutilization Strategy

On Optimum Causal Cognitive Spectrum Reutilization Strategy

Cooperative Sequential Spectrum Sensing Based on Level-Triggered Sampling

The impact of hardware implementation on the performance of spectrum sensing algorithms

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