• Journal of Satellite, Information and Communications
• /
• v.7 no.2
• /
• pp.30-35
• /
• 2012

In this paper, we proposed spectrum sensing using cooperative relay to solve problem of sensing performance degradation due to CPE (Customer-Primise equipments) which causes low SNR (signal-to-noise ratio) problem. This system model is expected that cooperative relay scheme guarantees the high sensing performance by its diversity gain. Based on these backgrounds, in this paper, we apply to cooperative relay scheme to the CR (cognitive radio) system, and simulation results show comparison of the sensing performance combining method EGC and MRC.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.271-273
• /
• 2013

인지 무선 네트워크에서 선순위 사용자의 통신을 보호하기 위해 차순위 사용자의 센싱 정확도는 매우 중요하다. 최근 센싱 성능을 개선하기 위해 협력적 센싱 기법이 연구되고 있다. 그러나 협력적 센싱 기법에서 차순위 사용자가 측정한 센싱 정보를 퓨전 센터로 피드백 할 때, 피드백 정보량에 따라 채널 오버헤드가 증가하므로 양자화된 제한된 정보를 퓨전 센터로 보고 한다. 본 논문은 양자화 비트 수에 따른 소프트 퓨전 방식의 성능을 평가한다.

• Journal of Satellite, Information and Communications
• /
• v.12 no.3
• /
• pp.98-102
• /
• 2017

In this paper, we study RF-powered backscatter cognitive radio networks to improve the performance for the secondary user which is backscatter radio based wireless sensors. In our proposed model, we consider an avoiding the doubly round-trip attenuation to add a carrier emitter and utilization of spectrum sensing information. When the primary channel is busy, the secondary user is able to harvest RF energy from the channel through a hybrid-access point (H-AP) and a carrier emitter. When the channel becomes idle, the secondary user will be use the harvested energy to operate wireless sensors, to use the sensing and to backscatter through the carrier emitter. We model mathematically the deterministic and multisource elements of a number of tagged channels. In the proposed communication environment, we show the BER performance of the backscatter communication using WiFi signal.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.10B
• /
• pp.1233-1239
• /
• 2011

The visible light convergence communication technology is suitable for indoor wireless communication and digital lighting fixtures, it could be used as lighting devices as well as a communication device. However, because that VLC is the technology of came to world a few years ago, there are many problems which had to solve. The signal sensing of VLC transmitter is one of the most challenging issue in VLC systems. Therefore in this paper, we analysis the performance of various sensing scheme for efficient detection of VLC systems. The signal of user is OFDM signal and the wirelss channel between a user and VLC system is modeled as indoor VLC channel. From the simulation results, it is confirmed that the proposed scheme is very effective to signal sensing for VLC systems.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.1
• /
• pp.89-93
• /
• 2009

In this paper, we investigated effect of sensing time on the performance of enhanced spectrum sensing method, which is the energy detector with multiples of verification using time delay, under Suzuki channel. We assumed that SNR is 1dB, $P_{FA}=0.1$ and various mobile speed such as 3, 60, 110 km/h. The performance is investigated by simulation and compared to that of conventional energy detector.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39B no.11
• /
• pp.790-802
• /
• 2014

In cognitive radio technology, secondary users can determine the absence of PU by periodic sensing operation and cooperative sensing between SUs yields a significant sensing performance improvement. However, there exists a trade off between the gains in terms of probability of detection of the primary users and the costs of false alarm probability. Therefore, the cooperation group must maintain the suitable size. And secondary users should sense not only the currently using channels and but also other candidates channel to switch in accordance with sudden appearance of the primary user. In this paper, we propose an effective group cooperative sensing algorithm in distributed network situations that is considering both of inband and outband sensing using evolutionary game theory. We derived that the strategy group of secondary users converges to an ESS(Evolutionary sable state). Using a learning algorithm, each secondary user can converge to the ESS without the exchange of information to each other.

• Journal of Satellite, Information and Communications
• /
• v.10 no.1
• /
• pp.49-55
• /
• 2015

In cognitive radio network (CRN), spectrum sensing is an elementary level of technology for non-interfering to licensed user. Required sample number for spectrum sensing is directly related to the throughput of secondary user and makes the tradeoff between the throughput of secondary user and interference to primary user. Required spectrum sensing sample is derived from required false alarm, detection probability and minimum required SNR of primary user (PU). If we make clustering and minimize the required transmission boundary of secondary user (SU), we can relax the required PU SNR for spectrum sensing because the required SNR for PU signal sensing is related to transmission range of SU. Therefore we can achieve efficient throughput of CRN by minimizing spectrum sensing sample. For this, we design the tradeoff between gain and loss could be obtained from clustering, according to the size of cluster members through game theory and simulation results confirm the effectiveness of the proposed method.

• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.344-348
• /
• 2009

Cognitive Radio(CR)는 특정 주파수 대역을 사용하도록 할당된 유저가 사용하지 않을 때, 이를 탐지하여 해당 주파수 대역을 이용함으로써 주파수 스펙트럼 효율을 향상시킬 수 있는 기술이다. 특히, CR에서 스펙트럼 센싱(Spectrum Sensing)은 중요한 기술의 하나라고 말할 수 있다. 기존의 스펙트럼 센싱 성능을 향상시키기 위한 방법으로, 다수의 노드가 각각 판정한 결과를 이용하는 OR-Rule, AND-Rule 등의 기법이 제안된 바 있다. 본 논문에서는 수신 다이버시티 기법 중의 하나인 Equal Gain Combiner(EGC) 알고리듬 이용하여 스펙트럼 센싱 성능을 알아보고 특히, 기존의 방법은 각 노드에서 판정 후 판정부에서 그 결과를 결합하여 최종 판정하는 방법이나, 본 논문에서 적용한 EGC 기법은 각 노드에서 수신된 신호에 대한 검출된 에너지 값을 융합센터(Fusion Center)로 보내어 최종 판정하는 방법이다. 각 노드에서 검출된 에너지 값을 융합센터가 수신한 신호에는 실질적으로 잡음이 섞이게 되므로 이로 인하여 발생할 수 있는 전송 오류를 추가적으로 고려하였다. 또한, 각 노드에서 검출한 에너지 값이 융합센터로 전송될 때에는 양자화 되어서 전송된다. 이에 따라서 양자화 bit수와 관련된 센싱 성능과 데이터의 반복 전송의 필요성, 그리고 그 횟수에 대해 제시하고자 한다.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.49 no.8
• /
• pp.98-103
• /
• 2012

Recently, the intelligent transportation system (ITS) that provides driver convenience and reduces the number of road casualties is in the spotlight. ITS must quickly deal with the emergency situation and provide information which drivers need. In ITS, a different channel will be assigned for each service to provide the service efficiently. However, if the channel is used at an emergency situation, the service cannot be provided immediately. For overcome this problem, we introduce the cognitive radio technology into ITS and propose a new spectrum sensing method in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39A no.1
• /
• pp.19-27
• /
• 2014

As frequency resource has taken on greater importance, Cognitive Radio(CR) technology has been considered as the solution to improve spectrum utilization by allowing a secondary user to utilize a licensed band when the primary user is absent. So spectrum sensing is significant part of CR for high performance. Recently, cooperative spectrum sensing that secondary users share each sensing results is proposed to improve spectrum sensing accuracy. In this paper, OR rule based cooperative spectrum sensing scheme using reporting error probability which occurs in user to fusion center(FC) channel The simulation results show that proposed scheme mitigates false alarm probability limitation which appears in existing cooperative spectrum sensing scheme by restricting the number of cooperating users using reporting error probability.