担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This study investigates hidden and exposed nodes in a low power wide area network (LPWAN) with the energy detection based carrier sense. Energy detection based carrier sense can drastically improve the performance of LPWANs, which is a type of wireless local network. However, hidden node problems are inherent in wireless local networks with carrier sense, and the upsurge of LPWANs with carrier sense results in exposed node problems. To evaluate the hidden and exposed nodes in the LPWAN, we define evaluation model that includes Own LPWAN and Interference LPWAN. Based on the model, hidden and exposed nodes in the LPWAN are evaluated for different distance between both LPWANs and different path loss exponent between end devices and gateway. The evaluation results show that exposed nodes are not expected to occur in the LPWAN when the gateway is located at the appropriate location where many of the end devices are located in the line-of-sight environment.

DOI： 10.1109/CCNC51664.2024.10454754

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This study investigates a scheme for the performance improvement of Sub-GHz band low power wide area networks (LPWANs) using an energy detection based carrier sense. The energy detection based carrier sense in the LPWAN has been theoretically analyzed. Although the carrier sense can improve several characteristics of the end devices, the energy consumption of the carrier sense is almost the same as that of the signal reception and cannot be ignored. In addition, the energy detection based carrier sense requires a long carrier sense period compared with the peak detection based carrier sense, which may further increase the energy consumption. Therefore, the performance improvement and energy consumption at the end devices must be jointly considered. Under these considerations, we propose an execution scheme of the energy detection based carrier sense at the end devices to improve the performance of poor conditioned end devices, that is, a large propagation loss to the gateway.

DOI： 10.1109/CCNC51664.2024.10454869

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This study investigates the characteristics of a long range wide area network (LoRaWAN) utilizing an energy detection based carrier sense. The authors have theoretically and numerically analyzed the energy detection based carrier sense and its characteristics in Sub-GHz band low-power wide-area networks (LPWANs), and numerically studied that the optimal carrier sense level depends on the packet length in networks. In previous studies, although LoRa signals were assumed to be LPWA signals, they were based on the assumption that all packets in a network have the same spreading factor and length. Since packets with different spreading factor are roughly orthogonal to each other, these evaluations are important in environments where several packets of different lengths are mixed. Therefore, in this study, characteristics of LoRaWAN utilizing the energy detection based carrier sense are discussed. The evaluation results show the roughly orthogonality of spreading factors changes the optimal carrier sense level in LoRaWAN.

DOI： 10.1109/ICOIN59985.2024.10572087

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this study, we investigate a spreading factor allocation method for extending the end device (ED) lifetime in LoRaWAN. Long range (LoRa) is a communication standard that has attracted attention because it can facilitate the construction of a local or private network. The authors have defined a constrained optimization problem for spreading factor allocation in LoRa Wanwith the average power consumption of EDs as the constraint, and have shown the solving method of the problem using a distributed genetic algorithm (GA). This study extends the approach by defining an optimization problem for power balancing by rotating the allocated spreading factor to reduce the increase in power consumption owing to the continuous use of high spreading factor by arbitrary EDs, and the solving method of the problem using a distributed GA is developed. The effectiveness of the studied method is demonstrated by computer experiments.

DOI： 10.1109/WF-IoT58464.2023.10539435

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Extensive research has been conducted on imperfect carrier sense based on energy detection; however, the effect of the finite packet length, finite carrier sense period, and arbitrary start time of the carrier sense for the arrived signal on the result of the energy detection based carrier sense has never been investigated. This paper presents a detailed discussion on the performances of an energy detection based carrier sense in low-power wide-area network (LPWAN) to detect a target signal with power below the noise power and employ it over a wide communication area. We theoretically derive the finite packet length, finite carrier sense period, and arbitrary start time of the carrier sense as the signal detection deterioration factors. The performance of LPWANs with the energy detection based carrier sense is numerically verified based on these theoretical analyses. The numerical examples demonstrate that the energy detection based carrier sense improves the performance of LPWANs, and an optimum carrier sense level is determined based on the width of the communication area and the packet length on air around the end devices.

DOI： 10.1109/ACCESS.2023.3299219

Kyutacar

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this study, we investigate robustness to power adjustment using digital settings at low-power wide-area (LPWA) module and a digital step attenuator in transmit power allocation for LPWA end devices under poor conditions, that is, high propagation loss to gateways. Traditionally, performance improvement techniques for end devices under poor conditions have been studied. In conventional techniques, employing analog stepless attenuator is assumed to adjust the transmit power at each end device. However, employing analog stepless attenuator at the end devices is not practical because each end device automatically adjusts its own transmit power. Therefore, we investigated the effect of the digital step attenuator and digital settings at LPWA module on the conventional techniques. Computer simulation results are presented to elucidate the characteristics of the conventional technique with the digital step attenuator and digital settings at LPWA module.

DOI： 10.1109/ICOIN56518.2023.10049053

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Coverage evaluation is necessary to derive the number of end devices that can be accommodated to wireless networks, and it is an evaluation metric for wireless network, such as low power wide area networks (LPWANs). In traditional analysis, conditional coverage probabilities are derived when the desired LoRa signal does not conflict with an interference signal and when the desired LoRa signal conflicts with a single interference signal. However, in the case that network load is 0.45, a probability of interference occurrence from two EDs is approximately 14.7%, whereas the probability from one EDs is approximately 36.1%. The difference between probabilities is approximately 20%, and we believe that it cannot be ignored on derivation of the number of accommodable end devices. In this study, we derive and evaluate the theoretical values of the conditional coverage probability when two interference signals arrive. Based on the probability, we derive a lower bound on the number of end devices that can be accommodated. Numerical examples are shown to validate the effectiveness of the derived lower bound on the number of accommodable end devices.

DOI： 10.1109/ICOIN56518.2023.10049040

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This study investigates the detailed radiowave propagation characteristics of sub-GHz band low-power wide-area (LPWA) communications in an indoor environment. Experiments are carried out in a five-storied reinforced concrete building. LPWA radiowave propagation is measured in the indoor environment, and the effect of such a part of the building on the LPWA radiowave propagation is discussed. The experimental results indicate that the part of the building such as the wall, affects the characteristics of the LPWA radiowave propagations.

DOI： 10.1109/ICOIN56518.2023.10048939

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

With the development of the Internet of Things, the number of low power wide area (LPWA) terminals and LPWA systems has been increasing in unlicensed Sub-GHz bands. Accordingly, it is expected that radio frequency resources will be depleted remarkably, which may cause frequent intra-system and inter-system interferences at gateway (GW) of each system. Thus, we propose power-domain successive interference cancellation (SIC) among multiple LPWA systems. In our method, it is assumed that the GW has modulators and demodulators of multiple systems and can accumulate superposed and received signals. In the SIC algorithm, first, the GW modulates demodulated binary sequence as a replica signal with the modulator of the same system as the demodulator. Then, the GW subtracts the replica signal from the accumulated signals so that the GW can attempt to demodulate the subtracted signals iteratively. Because of the aforementioned assumptions, the subtracted signals can be shared among the demodulators of multiple systems. Simulation results show that our proposed method can significantly reduce packet error rate for the whole system compared to the conventional demodulation without the SIC at the GW of each system.

DOI： 10.23919/APSIPAASC55919.2022.9980010

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this paper, we propose an energy detection based signal detection algorithm that can reduce power consumption by decreasing the number of samples when the target signal seems to be absent. The general concept of the proposed technique is the same as that of light-emitting diode dynamic lighting systems for energy efficiency, and decreasing the number of samples for signal detection can be achieved under the assumption of dynamic power management technologies, such as clock gating or power gating, which can reduce the power consumption of digital hardware. To avoid the deterioration of signal detection accuracy owing to the continuous signal detection mentioned above, traditional energy detection is executed when the target signal seems to be present. In the proposed algorithm, the transition between the two types of signal detection schemes is determined by the previous signal detection results. Numerical examples are presented to demonstrate the fundamental characteristics of the proposed signal detection algorithm.

DOI： 10.1109/IGESSC55810.2022.9955324

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this paper, we investigate the radio wave prop-agation of sub-GHz band low power wide area (LPWA) communications. To reveal the spatial propagation characteristics of LPWA signals for wireless sensor networks in detail, we measured the propagation at half-wavelength intervals in a square area of approximately 5 m for both line-of-sight (LOS) and non-line-of-sight (NLOS) environments. The measurement results show that the differences between the maximum and minimum average received signal strength indicator (RSSI) values were 30 dB for the LOS signal and 20 dB for the NLOS signal. Furthermore, frequency analysis results of the measured RSSI in both environments quantitatively showed a spatial correlation of the measured RSSI.

DOI： 10.1109/FNWF55208.2022.00082

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This letter proposes a throughput estimation technique for wireless local area network (WLAN) traffic in multiple channels using a software based packet analyzer. The proposed technique can artificially realize the simultaneous estimation of WLAN throughput in multiple channels by switching to a target channel at a high speed while running the software based packet analyzer. The proposed technique is evaluated using two types of WLAN traffic, i.e., constant bit rate traffic and variable bit rate traffic, which can simulate actual Web browsing behavior. Experimental results are presented to evaluate the proposed technique and validate its effectiveness.

DOI： 10.1109/LNET.2022.3191217

Scopus

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper presents a novel transceiver architecture for in-band full duplex radio. A transceiver for full duplex radio requires a self-interference (SI) canceler to remove the SI occurring from the transmitter to the receiver, and a full duplex transceiver generally has two SI cancelers: one at the analog RF stage and the other at the baseband stage. The output from the SI canceler at the RF stage includes much residual SI, and it decreases the number of bits allocated to the analog baseband signal at the analog-to-digital converter. A 1-tap analog baseband SI canceler that uses a replica signal including only the direct path component of the residual SI has been presented for preventing degradation. However, the architecture cannot remove the SI well due to the high Ricial K-factor. To address the problem, the presented architecture has an SI canceler at the analog baseband stage, and this canceler employs a replica signal that is output from a digital-to-analog converter. Because the replica signal is generated in the digital domain, the architecture can generate a multipath replica signal, and improved performance can be expected. Numerical and theoretical analyses are shown to validate the effectiveness of the presented architecture.

DOI： 10.1007/s11277-022-09821-9

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This study investigates the effect of buildings on the accuracy of Kriging interpolation result for estimating for the received signal strength indicator (RSSI) in the sub-GHz band. The RSSI values can be estimated using Kriging interpolation, which is an interpolation method and that depends on the distance and shadowing components. Traditionally, the accuracy of estimation by Kriging interpolation in the neighborhood of a building has never been verified. In this study, analyses of the accuracy of Kriging interpolation in the neighborhood of a building are provided by comparing the actual observed RSSI values with the values estimated by Kriging interpolation. This study verifies that the estimation accuracy can be improved by changing the area where the observations used for Kriging interpolation are obtained and by increasing the number of observations used for interpolation, even in the neighborhood of buildings. In addition, estimation accuracy can be improved by obtaining the observed value from the area near the interpolated location.

DOI： 10.1109/ICUFN55119.2022.9829595

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper investigates characteristics of transmit power allocation technique in low-power wide-area networks (LPWANs) with a carrier sense. Traditionally, we have studied the performance improvement technique for the end devices with high path loss to the gateway in the LPWAN. The technique can improve the performance of such end devices by allocating the transmit power so as to provide the benefit of the capture effect for all end devices. However, the effectiveness of the technique in the LPWAN with the carrier sense has never been verified. In Japan, wireless transceivers in sub-GHz band shall execute the carrier sense based on peak detection before transmitting a packet, and the performance must be verified. Numerical examples are provided to analysis the characteristics of the conventional technique in the LPWAN with the carrier sense based on peak detection.

DOI： 10.1109/ICUFN55119.2022.9829650

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper studies the performance improvement of end devices with a low received signal strength indicator, that is, the poor condition, in general low power wide area networks (LPWANs). To improve the performance, we discuss the transmit power allocation utilizing the benefit of the capture effect, which results in an advantage depending on the signal-to-noise ratio and signal-to-interference ratio at each end device. However, the benefit of the capture effect cannot be realized simultaneously in all end devices owing to its characteristics. To avoid performance degradation of the specific end devices that are unable to realize the benefit of the capture effect, we propose transmit power allocation schemes. In the proposed technique, two types of allocated transmit power, which are designed in conjunction with each other, are used alternately in time. Numerical examples validate the effectiveness of the proposed technique.

DOI： 10.1109/ACCESS.2022.3168139

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper proposes spatial and temporal correlation analyses of environmental information measured at wireless sensor networks. The purpose of the analysis is to visualize the behavior of spatial and temporal changes in physical quantities, such as temperature, that cannot be found from only the average relative error. The analysis will enable the fundamental discussion for the optimal placement of sensor nodes with physical sensors. Actual measurement results are analyzed according to the proposed analysis method. The analytical results showed the existence of the behavior for the physical quantity temporal changes which is difficult to find from only the average relative error.

DOI： 10.1109/SENSORS47087.2021.9639557

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In recent years, Long Range Wide Area Network (LoRaWAN) has attracted attention because it enables long-distance communication with low power. LoRaWAN adopts the MAC protocol is based on Pure ALOHA and the terminal can send packets at any time. However, the problem is that packet collisions frequently occur as the number of terminals increases. On the other hand, Bluetooth Low Energy (BLE) which is standardized for short-distance communication for IoT is now widely used in various IoT devices because it enables high speed and stable communication. Therefore, we proposed a method that can reduce the traffic on the LoRaWAN by dynamically selecting LoRaWAN and BLE when the terminals move in an environment where it can use both systems. However, it is necessary to consider the Quality of Service (QoS) requirements which are the application requirements of the terminal because LoRaWAN and BLE is standardized supposed different target applications. Therefore, in this paper, we propose a method that can adaptively select a system by weighting the QoS realizations of each system such as the packet error rate predicted using the spectrum database and the power consumption during communication with the application requirements of the terminal.

DOI： 10.1109/icoin50884.2021.9333955

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this paper, we discuss time correlation char-acteristics for measurement results of carbon dioxide (CO2) concentration in outdoor environments. The purpose of this paper is to collect an information for the effective placement of sensor nodes in wireless sensor networks (WSNs). We observed CO2 concentration using WSNs based on low-power wide area networks (LPWANs). To measure CO2 concentration in outdoor environments, some sensor nodes with CO2 sensor are deployed in Kamihama campus, Mie University, Japan, and CO2 concen-tration on the area are measured using LPWAN based WSN. We provide the time correlation characteristics based on the measurement results, and the time correlation characteristics of CO2 concentration are compared with that of relative humidity.

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In order to understand the heat island phenomenon or air pollution caused by PM2.5, it is necessary to accurately measure physical quantities, which can be measured systems based on a wireless sensor network (WSN). For the purpose, it is necessary to consider the optimal placement of sensors considering cost for the installation. We develop 920MHz band wireless sensor network for the measurement of some quantities including temperature, relative humidity, atmospheric pressure and dust. The developed system is based on LoRa networks. We measure these quantities in the actual environment (Kamihama campus at Mie University) and consider the tendency of the measured value for each observed quantities. In this paper, based on the measurement results, the spatially and temporally characteristics of each measured quantity for the optimal placement of EDs in LPWAN based WSN.

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper provides theoretical analyses for maximum cyclic autocorrelation selection (MCAS)-based spectrum sensing techniques in cognitive radio networks. The MCAS-based spectrum sensing techniques are low computational complexity spectrum sensing in comparison with some cyclostationary detection. However, MCAS-based spectrum sensing characteristics have never been theoretically derived. In this study, we derive closed form solutions for signal detection probability and false alarm probability for MCAS-based spectrum sensing. The theoretical values are compared with numerical examples, and the values match well with each other.

DOI： 10.1587/transcom.2019EBP3175

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper presents a novel spectrum sensing technique based on selection diversity combining in cognitive radio networks. In general, a selection diversity combining scheme requires a period to select an optimal element, and spectrum sensing requires a period to detect a target signal. We consider that both these periods are required for the spectrum sensing based on selection diversity combining. However, conventional techniques do not consider both the periods. Furthermore, spending a large amount of time in selection and signal detection increases their accuracy. Because the required period for spectrum sensing based on selection diversity combining is the summation of both the periods, their lengths should be considered while developing selection diversity combining based spectrum sensing for a constant period. In reference to this, we discuss the spectrum sensing technique based on selection diversity combining. Numerical examples are shown to validate the effectiveness of the presented design techniques.

DOI： 10.1587/transfun.2019EAP1167

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper presents a novel statistic computation technique for energy detection-based spectrum sensing with multiple antennas. The presented technique computes the statistic for signal detection after combining all the signals. Because the computation of the statistic for all the received signals is not required, the presented technique reduces the computational complexity. Furthermore, the absolute value of all the received signals are combined to prevent the attenuation of the combined signals. Because the statistic computations are not required for all the received signals, the reduction of the computational complexity for signal detection can be expected. Furthermore, the presented technique does not need to choose anything, such as the binary phase rotator in the conventional technique, and therefore, the performance degradation due to wrong choices can be avoided. Numerical examples indicate that the spectrum sensing performances of the presented technique are almost the same as those of conventional techniques despite the complexity of the presented technique being less than that of the conventional techniques.

DOI： 10.1587/transfun.2019EAP1115

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper discusses a spreading factor allocation for Long Range Wide Area Network (LoRaWAN). Because Long Range (LoRa) is based on chirp spread spectrum that each spreading factor is approximately orthogonal to each other, the performance of LoRaWAN can be enhanced by allocating the spreading factor appropriately to end devices (EDs). Several spreading factor allocation techniques have been reported. Techniques shown in existing studies can improve some characteristics (e.g. throughput or packet reception probability (PRP)); however, there are a few studies that have focused on the energy consumption of the EDs. The LoRa communication offers a low power communication and this enables the improvement of the performance in exchange for the energy consumption. This paper presents a performance improvement technique via spreading factor allocations for LoRaWAN. We define the optimization problem for the spreading factor allocation to maximize the PRP under a constraint for the average energy consumption of all the EDs. It enables for the performance improvement under the constraint of the average energy consumption of all the EDs by solving the problem. This study further develops a method to solve the defined problem based on a distributed genetic algorithm, which is metaheuristics method. Although the techniques shown in the existing studies give the average energy consumption as a result of the performance improvement by the spreading factor allocation, the presented technique can enhance the LoRaWAN performance by allocating the spreading factor to EDs under the constraint for the average energy consumption of all the EDs. Numerical examples validate the effectiveness of the presented technique. The PRP performance of the presented technique is superior to that of the techniques shown in the existing studies despite that the average energy consumption of all the EDs of the presented technique is less than that of the techniques shown in the existing studies.

DOI： 10.3390/s20164417

Kyutacar

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper analyzes the effect of energy detection based listen before talk (LBT) time (or detection level of the LBT) on the current consumption of end devices in LoRa networks. The analysis results are based on signal detection theorem based analysis which has been introduced in our previous work. The results show that the current consumption of the LBT cannot be ignored in comparison with that of the packet transmission and show the effect of the LBT on the current consumption must be considered in the design of LoRa networks.

DOI： 10.1109/ICOIN48656.2020.9016530

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper provides analysis results that the effect of energy detection based listen before talk (LBT) time (or detection level of the LBT) on the performance of LoRa Networks. We introduce an approximated analysis method based on signal detection theorem, and we provide a collision probability based analysis results. The results show that the LBT time must be optimized for the improvement of LoRa network performances.

DOI： 10.1109/DySPAN.2019.8935847

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Maximum cyclic autocorrelation selection (MCAS)-based spectrum sensing is one of the low complexity spectrum sensing techniques in cyclostationary detection techniques. However, spectrum sensing features of MCAS- based spectrum sensing have never been theoretically derived. This paper provides a derivation result of spectrum sensing characteristics for MCAS-based spectrum sensing in cognitive radio networks. In this study, we derive closed form solutions for signal detection probability and false alarm probability for MCAS-based spectrum sensing. The theoretical values are compared with numerical examples, and the examples demonstrate that numerical and theoretical values match well with each other.

DOI： 10.1109/VTCFall.2019.8891131

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Private/local wireless networks based on LoRa with Internet of Things (IoT) devices has been paid much attention. Important issues of the LoRa based network are non-line-of-sight (NLOS) environment and inappropriate of LoRa gateway. This paper studies propagation characteristics for LoRa communications operated at 920MHz band in a harsh environment, which is assumed that i) numerous NLOS environment in the communication area and ii) high buildings surrounding the LoRa gateway. For the evaluation of the propagation characteristic in the harsh environment, we measure averaged received signal strength indicator (RSSI) values in a university campus. Based on the measurement results, we obtain the outage probability and the path loss model. These results indicate that the harsh environment causes the reduction of the communication area, i.e., the path loss model which is obtained from the measurement data almost follows COST-231 Walfisch- Ikegami model.

DOI： 10.1109/VTCFall.2019.8891540

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This letter presents a computational complexity reduction technique for space diversity based spectrum sensing when the number of receive antennas is greater than three (NR ≥ 3 where NR is the number of receive antenna). The received signals are combined with phase inversion so as to not attenuate the combined signal, and a statistic for signal detection is computed from the combined signal. Because the computation of only one statistic is required regardless of the number of receive antenna, the complexity can be reduced. Numerical examples and simple analysis verify the effectiveness of the presented technique.

DOI： 10.1587/transfun.E102.A.974

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper presents weight computation techniques for spectrum sensing based on a cyclic autocorrelation function (CAF) shared diversity combining. We had reported that the performance of signal detection can be improved by the weight factor obtained from time-Averaged of the CAF values, and the technique is based on cyclostationary detection based spectrum sensing. In the technique, time-Averaged CAFs are used to extract a channel state information and compute a weight factor for the spectrum sensing based on the CAFs. However, the weight factor also includes the CAFs computed by purely additive white Gaussian noise, and the performance of signal detection degrades. In this paper, only the CAFs when it is judged that a primary user is presence are employed to obtain the time-Averaged CAF. The presented results show that the performance of signal detection can be improved as compared with the conventional weight computation technique.

DOI： 10.1109/ICAIIC.2019.8668968

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