• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.911-923
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• 2014

Ad hoc cognitive radio wireless sensor networks allow secondary wireless sensor nodes to recognize spectrum opportunities and transmit data. Most existing protocols proposed for ad hoc cognitive radio wireless sensor networks require a dedicated common control channel. Allocating one channel just for control packet exchange is a waste of resources for channel-constrained networks. There are very few protocols that do not rely on a common control channel and that exchange channel-negotiation control packets during a pre-allocated time on the data channels. This, however, can require a substantial amount of time to access the channel when an incumbent is present on the channel, where the nodes are intended to negotiate for the data channel. This study examined channel access delay on cognitive radio wireless sensor networks that have no dedicated common control channel.

• International journal of advanced smart convergence
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• 제13권1호
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• pp.1-11
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• 2024

Cognitive small cell networks, consisting of macro-cells and small cells, are foreseen as a promising candidate solution to address 5G spectrum scarcity. Recently, many technological issues (such as spectrum sensing, spectrum sharing) related to cognitive small cell networks have been studied, but the common control channel (CCC) establishment problem has been ignored. CCC is an indispensable medium for control message exchange that could have a huge significant on transmitter-receiver handshake, channel access negotiation, topology change, and routing information updates, etc. Therefore, establishing CCC in cognitive small cell networks is a challenging problem. In this paper, we propose a potential game theory-based approach for CCC establishment in cognitive radio networks. We design a utility function and demonstrate that it is an exact potential game with a pure Nash equilibrium. To maintain the common control channel list (CCL), we develop a CCC update algorithm. The simulation results demonstrate that the proposed approach has good convergence. On the other hand, it exhibits good delay and overhead of all networks.

• Journal of Communications and Networks
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• 제14권6호
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• pp.710-718
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• 2012

The implementation of a common control channel is one of the most challenging issues in cognitive radio networks, since a fully reliable control channel cannot be created without reserving bandwidth specifically for this purpose. In this paper, we investigate a promising solution that exploits the ultra wide band (UWB) technology to let cognitive radio nodes discover each other and exchange control information for establishing a communication link. The contribution of this paper is threefold: (i) We define the communication protocol needed to let cognitive radio nodes discover each other and exchange control information for link set up, (ii) we overcome the gap in coverage, which typically exists between UWB and long-medium range technologies, by using multi-hop communication, (iii) we evaluate the performance of our approach by adopting an accurate channel model and show its benefits with respect to an in-band signaling solution.

• 산업공학
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• 제17권3호
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• pp.294-304
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• 2004

In the IS-95 packet service system, the radio channels are generally classified into the dedicated and common traffic channels. In this paper, the performance of the common traffic channel access method is evaluated using simulation. The simulation results are compared with those of random access method. Simulation results show that the capacity can be increased up to 25% by applying the proposed common channel access method. The delay problem and variance of BER are also discussed.

• 한국경영과학회지
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• 제28권3호
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• pp.169-184
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• 2003

In the IS-95 packet service system, the radio channels are generally classified into the dedicated and the common traffic channels. In this paper, a common traffic channel access method is proposed for the COMA packet service system to enhance the radio resource utilization while guaranteeing QoS to the users. The proposed method is based on the permission probability for the common traffic channel user. To derive permission probability, optimization models are developed for two different QoS constraints. Approximation methods are also developed.

• 한국통신학회논문지
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• 제35권2A호
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• pp.153-164
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• 2010

본 논문은 무선 애드혹 네트워크에서 채널 효율성 및 네트워크 성능 향상을 위한 멀티채널 MAC 프로토콜을 제안한다. 멀티채널 MAC 프로토콜 설계에는 랑데부 문제(rendezvous problem)와 멀티채널 히든 노드 문제 등 두개의 주요한 문제가 있다. 기존에 제안된 여러 멀티채널 MAC 프로토콜에서는 하나의 채널을 공통 컨트롤 채널로 사용하여 컨트롤 패킷 교환을 통해 이러한 문제들을 해결하였는데, 이것은 데이터 채널이 증가할수록 높은 경쟁으로 인한 공통 컨트롤 채널의 병목 현상을 초래하여 비효율적인 데이터 채널 이용의 원인이 된다. 본 논문에서 제안하는 멀티채널 MAC 프로토콜은 멀티채널 히든 노드 문제를 해결하기 위해 TDMA 방식을 사용하였고, 데이터를 동시에 송수신할 수 있도록 하여 네트워크 성능을 높인다. 또한 공통 컨트롤 채널을 사용하지 않기 때문에 공통 컨트롤 채널 병목 현상이 발생하지 않고, 전송 또는 수신할 데이터가 없는 노드는 슬립(sleep) 상태를 유지하도록 하여 에너지 절감(energy savings)이 가능하다. 모의실험결과는 제안한 MAC 프로토콜이 기존의 방법에 비해 네트워크 성능 및 채널 효율성을 향상시키고 에너지를 절감할 수 있다는 것을 보여준다.

• Journal of Communications and Networks
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• 제13권4호
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• pp.319-326
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• 2011

Beamforming techniques have been successfully utilized for traffic channels in order to solve the interference problem. However, their use for control channels has not been sufficiently investigated. In this paper, a (semi-) centralized beamforming strategy that adaptively changes beam patterns and controls the total transmit power of cells is proposed for the performance enhancement of the common channel in hierarchical cell structure (HCS) networks. In addition, some examples of its practical implementation with low complexity are presented for two-tier HCS networks consisting of macro and pico cells. The performance of the proposed scheme has been evaluated through multi-cell system-level simulations under optimistic and pessimistic interference scenarios. The cumulative distribution function of user geometry or channel quality has been used as a performance metric since in the case of common control channel the number of outage users is more important than the sum rate. Simulation results confirm that the proposed scheme provides a significant gain compared to the random beamforming scheme as well as conventional systems that do not use the proposed algorithm. Finally, the proposed scheme can be applied simultaneously to several adjacent macro and pico cells even if it is designed primarily for the pico cell within macro cells.

• 한국통신학회논문지
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• 제33권5A호
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• pp.549-560
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• 2008

본 논문은 무선 네트워크 환경에서 채널 효율성을 높이기 위하여 두 개의 인터페이스를 사용하는 새로운 멀티채널 MAC 프로토콜을 제안하였다. 멀티채널 환경에서 기존에 제안된 대부분의 연구들은 컨트롤 메시지를 교환하기 위하여 공통 컨트롤 채널을 사용하였는데, 이것은 데이터 채널이 증가할 때 공통 컨트롤 채널에서 병목 현상을 야기 시킨다. 본 논문에서는 제안하는 멀티채널 MAC 프로토콜은 송수신용 채널을 분리하여 데이터와 컨트롤 패킷을 동시에 송수신하여 전체 네트워크 처리량을 높이고, 공통 컨트롤 채널이 없기 때문에 병목현상 문제가 발생하지 않는다. 또한 TDMA 방식을 사용하여 데이터 패킷과 컨트롤 패킷의 충돌을 피할 수 있고, 멀티채널환경에서 송수신 인터페이스가 다를 경우 발생하는 CTS 패킷이나 ACK 패킷의 충돌 가능성을 줄였다. 모의실험결과는 제안된 멀티채널 MAC 프로토콜이 기존의 방법과 비교해서 전체 네트워크 처리량과 채널 효율성을 크게 향상시키는 것을 보여준다.

• 산업기술연구
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• 제18권
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• pp.439-442
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• 1998

In this paper, we firstly suggested C&D (Common mode and Differential mode) model for the representation of a stereophonic signal. Then a measure of stereophonic channel separability is defined as the ratio of differential mode energy to total energy in frequency domain. After that, a new channel separability enhancement scheme is proposed by the control of common mode rejection. Finally, some experimental results are presented in order to verify our scheme.

• Journal of Computing Science and Engineering
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• 제7권2호
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• pp.81-88
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• 2013

In cognitive radio or dynamic spectrum access networks, a rendezvous represents meeting two or more users on a common channel, and negotiating to establish data communication. The rendezvous problem is one of the most challenging tasks in cognitive radio ad hoc networks. Generally, this problem is simplified by using two well-known mechanisms: the first uses a predefined common control channel, while the second employs a channel hopping procedure. Yet, these two mechanisms form a life cycle, when they simplify the rendezvous problem in cognitive radio networks. The main purpose of this paper is to point out how and why this cycle forms.