• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.122-127
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• 2012

The purpose of this study is to know about the interference on FM Radio channel from HD Radio signal. In Korea, a data service channel, named DARC is operated by a major FM radio broadcaster which has national wide service area. Therefore, an analysis of the interference on FM radio channel with DARC data channel from HD Radio, most recently developed digital radio system. Technical parameters of FM radio with DARC data channel and HD Radio system are considered for this simulation. As results some interference generated because of HD Radio signal according to its signal allocation and service mode of HD Radio.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.285-288
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• 2010

In this paper, we present a very useful method for updating digital satellite radio broadcast channel information. When a devices equipped with function to receive Digital Satellite Radio such as Home Theater, MP3 player, mobile phones, car audio system and various other types of Digital Devices, receives new Digital satellite radio (will be mentioned as XM radio onwards) broadcast channel information, only the current received XM radio broadcast channel and N number of pre/post nearby broadcast channels are scanned randomly in zigzag manner. Then the previous XM radio broadcast channel information updated with the newly received XM radio broadcast channel information. Since this method can prevent batch update for all XM radio channel, including some channels which less likely did not select by user, update process for real time frequently changed XM radio broadcast channel information can be performed efficiently with minimal or without delay.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.35-40
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• 2011

The purpose of this study is to know about the interference on FM Radio channel from DRM+ signal. In Korea, a data service channel, named DARC is operated by a major FM radio broadcaster which has national wide service area. Therefore, an analysis of the interference on FM radio channel with DARC data channel from DRM+, most recently developed digital radio system. Technical parameters of FM radio with DARC data channel and DRM+ system are considered for this simulation. To maintain without no interference from DRM+, FM radio channel with DARC data channel should have the power level difference over 14.7dB at 150KHz frequency distance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.803-809
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• 2011

In this paper, we present a very useful method for updating digital satellite radio broadcast channel information. When a devices equipped with function to receive Digital Satellite Radio such as Home Theater, MP3 player, mobile phones, car audio system and various other types of Digital Devices, receives new Digital satellite radio (will be mentioned as XM radio onwards) broadcast channel information, only the current received XM radio broadcast channel and N number of pre/post nearby broadcast channels are scanned randomly in zigzag manner. Then the previous XM radio broadcast channel information updated with the newly received XM radio broadcast channel information. Since this method can prevent batch update for all XM radio channel, including some channels which less likely did not select by user, update process for real time frequently changed XM radio broadcast channel information can be performed efficiently with minimal or without delay.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.104-114
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• 2009

In this paper, a technique is proposed that enables secondary users to evaluate channel availability in cognitive radio networks. Here, secondary users estimate the utilization of channels via predicting the traffic pattern of primary user, and select a proper channel for radio transmission. The proposed technique reduces the channel switching rate of secondary users (the rate of switching from one channel to another) and the interference on primary users, while maintaining a reasonable call blocking rate of secondary users.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.351-356
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• 2010

We investigated the combined effect of fiber chromatic dispersion and self-phase modulation (SPM) in multi-channel subcarrier multiplexed (SCM) optical transmission systems. We theoretically analyzed the transmission characteristics of the SCM signals with the effect of SPM and chromatic dispersion in a single-mode optical fiber by numerical simulations based on the nonlinear Schrodinger equation. The numerical simulation results revealed that the effect of fiber dispersion and SPM could occur independently between subcarrier channels in two-channel SCM systems for small optical modulation index (OMI) and large channel spacing. However, for large OMI, small channel spacing, and large fiber launching power, we found a performance degradation of the two-channel system compared to that of a single-channel system. These parameters are therefore important for the optimization of multi-channel SCM systems applicable to radio over fiber networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.35-41
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• 2017

To solve the shortage of radio spectrum and utilize spectrum resource more efficiently, cognitive radio technologies are proposed, and many studies on cognitive radio have been conducted. Multi-hop routing is one of the important technologies to enable the nodes to transmit data further with lower power in ad-hoc cognitive radio networks. In a multi-channel cognitive radio networks, each channel should be allocated to minimize interference to primary users. In the multi-hop routing, channel allocation should consider the inter-channel interference to maximize network throughput. In this paper, we propose multi-channel scheduling scheme which minimizes inter-channel interferences and avoids collision with primary users for the multi-hop multi-channel cognitive radio networks. The proposed scheduling is designed to determine both of routing path and channel selection. The performance of proposed channel allocation scheme is evaluated by the computer simulation in the aspect of capacity and collision rate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1723-1728
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• 2010

In this paper we concentrate design and develop method about Multi-Channel Internet Radio Platform to broadcast music contents in large outlet and between spaces to protect music contents which have drastically widespread demage. we provide application concept and design rule of hardware path for Multi-Channel Connection and Multi Stream.

• Journal of information and communication convergence engineering
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• v.9 no.1
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• pp.27-31
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• 2011

This paper describes the optimization of spectrum sensing in terms of the throughput of a cognitive radio (CR) system. Dealing with the optimization problem of spectrum sensing, this paper evaluates the throughput of a CR system by considering such situations as the penalty time of a channel search and incumbent user (IU) detection delay caused by a missed detection of an incumbent signal. Also, this paper suggests a serial channel search scheme as the search method for a vacant channel, and derives its mean channel search time by considering the penalty time due to the false alarm of a vacant channel search. The numerical results suggest the optimum sensing time of the channel search process using the derived mean channel search time of a serial channel search in the case of a sensing hardware structure with single radio frequency (RF) path. It also demonstrates that the average throughput is improved by two separate RF paths in spite of the hardware complexity of an RF receiver.