S. Anuradha

Optimization of cooperative spectrum sensing based on improved energy detector with selection diversity in AWGN and Rayleigh fading

In this paper, an optimized cooperative spectrum sensing (CSS) network, in which each cognitive radio (CR) uses multiple antennas and an improved energy detector is proposed. The performance is evaluated by optimizing the network parameters such as number of CR users and normalized detection threshold. We have derived the suitable expressions for optimum value of normalized threshold in Rayleigh fading channel for single and multiple antenna case and optimum number of CRs for both AWGN and Rayleigh fading channels. Finally, optimal values of number of CRs and normalized detection threshold is calculated for different values of average sensing channel SNR, normalized threshold, and multiple antennas at each CR. Comparison between conventional energy detector (CED) and improved energy detector (EED) is also provided.

Hybrid PAPR reduction scheme with selective mapping and tone reservation for FBMC/OQAM

Filter Bank Multicarrier (FBMC) has been proven to be a promising multi-carrier modulation (MCM) technique. However FBMC has also the intrinsic disadvantage of high peak to average power ratio (PAPR) that should be alleviated. This paper presents a new hybrid peak-to-average power ratio reduction technique, which combines a selective mapping method with a tone reservation method. Simulation results show that our proposed method has better performance than other typical existing methods.

Adaptive Clipping-Based Active Constellation Extension for PAPR Reduction of OFDM/OQAM Signals

The active constellation extension (ACE) based on clipping technique is a lossless, simple and attractive peak-to-average power ratio (PAPR) reduction technique in orthogonal frequency division multiplexing with offset quadrature amplitude modulation system. But, when the target clipping level is set below an initially unknown optimum value, we observe that it cannot achieve the minimum PAPR. To overcome this low clipping level problem, a novel ACE algorithm with adaptive clipping control is proposed in this paper. First, an adaptive strategy is used to control the size of clipping level A. Secondly, a novel step factor

New error function companding technique to minimize PAPR in LTE uplink communications

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Correction to: Performance Analysis of Cooperative Spectrum Sensing Network Using Optimization Technique in Different Fading Channels

μ is adopted, to complete iterative computations in order to increase the convergence speed. Simulation results validate that the proposed algorithm has reduced the PAPR and improved the convergence speed significantly without any side information and any processing at the receiver end.

Performance analysis and threshold selection in co-operative spectrum sensing using soft-decision techniques

This paper describes about the performance analysis and comparison between hard decision (majority rule) logic and soft decision (maximal ratio combining) logic approaches using cooperative spectrum sensing (CSS) with censoring scheme. We have considered both sensing channel (S-channel) and reporting channel (R-channel) are affected by Rician fading. Radio links present in the channel gets heavily faded and the information received at the fusion center (FC) becomes erroneous because of fading effect present in the channel. Threshold based censoring scheme is used to eliminate the heavily faded cognitive radios (CRs) in R-channel. Two fusion rules namely, majority logic and maximal ratio combining (MRC) are considered individually at the fusion center to estimate the performance of CSS by censoring of R-channel links. The performance is evaluated in terms of missed detection probability (

Overlapped segmental Active Constellation Extension for the PAPR reduction of the OFDM/OQAM system

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