Joo-Seok Kim

MIMO Radio Channel Measurement and Analysis at 781MHz

Abstract In this paper, the measurement data is analyzed and channel parameters are derived through MIMO Channel measurements at 781MHz considering outdoor multi-path environment. 781MHz frequency band currently operates the DTV system. However, it will be allocated new mobile communication frequency band. The channel characteristics at 781MHz seem to be similar existing mobile communication system at 900MHz but a study on channel characteristics of signal transfer process is necessary because there is incomplete study in mobile networks at 781MHz. To avoid interference with Korean DTV broadcasting, we measured channel characteristics in city/suburban areas of Jeju island by channel sounder and 4×4 antenna of the ETRI(Korea Electronics and Telecommunications Research Institute). Path Loss, Delay Spread, Angular Spread and K-factor were derived based on measured data. Key Words : MIMO, Path Loss, Delay Spread, Angular Spread, K-factor * 준회원, 충북대학교 전파공학과 ** 준회원, 한국전자통신연구원 전파기술연구부 ***

The efficient Channel allocation method for Korean HD Radio System

The Korean radio broadcasting system is analog. Compared with digital radio, the analog radio decreases the frequency efficiency. HD Radio is the method where the digital signal is transmitted on either side of the analog PM signal. Therefore, without relocating the analog frequency can transmit digital signals. If interference between analog and digital signal occurs it is impossible to receive smoothly, so HD Radio interference with existing analog PM will be analyzed. In this paper, based on Mt.Gwae-Bang stations within +-400kHz frequency of l03.5MHz, and to use the station to station by specifying the HD Radio channel interference, place the structures were analyzed. Through this paper, the reader of a digital radio frequency interference in the system know that it may obtain information about.

Analysis of Receiving Environment Changes According to Channel Reallocation Method of Terrestrial DMB

Abstract Many communications and broadcast media have emerged by the rapid development of wireless communication and broadcasting technologies, so the radio resources are insufficient for these services. DMB can use the regional integrated channel due to the SFN broadcasting network, so DMB uses the frequency efficiently. However, the domestic DMB uses the existing analog TV frequency band and uses a plurality of channels in some areas because of the interference with the analog TV. However, the broadcasting of the analog TV was terminated, so the channel reallocation of the terrestial DMB is necessary for the efficient use of frequencies. This paper proposes the channel reallocation method of the terrestial DMB and analyzes the change of transmission and reception environments by using simulations. Key Words : Terrestial DMB, Channel reallocation, SFN, Interference analysis * 준회원, 충북대학교 전파통신공학과 ** 정회원, 충북대학교 전파통신공학과, 교신저자접수일자 2013년 11월 28일, 수정완료 2013년 12월 11일게재확정일자 2013년 12월 13일Received: 28 November, 2013 / Revised: 11 December, 2013 Accepted: 13 December, 2013

Radio Propagation Characteristics Analysis for Various Receiving Environments of Satellite Communication on Ka-band

Abstract In this paper, the signal reception environment of the satellite communications was analyzed on urban, suburban and rural environment. The correct analysis of received environment is very important in the satellite communications because the presence of various attenuation factors. Analyze attenuation factor through the simulation and that apply to each receiving environment. The urban and suburban various received sensitivity is determined according to building height and density. Moreover, attenuation occurs in rural areas due to the mountainous and vegetation. In this paper, we analysis of variety receiving environment according to movement of the ground station and the satellites can be utilized to provide stable multimedia services. Key Words : Satellite communication, Propagation, attenuation, Diffraction attenuation, Path search algorithm * 준회원, 충북대학교 전파통신공학과 ** 준회원, IM Technology *** 준회원, 국방과학연구소 **** 정회원, 충북대학교 전파통신공학과, 교신저자접수일자 2013년 1월 11일, 수정완료 2013년 2월 7일게재확정일자 2013년 2월 8일Received: 11 January 2013 / Revised: 7 February 2013 /Accepted: 8 February 2013

The optimal placement of radio stations in coexisting DRM+ and analog FM systems

Currently in wireless communication technology, digital radio systems are replacing analog radio systems. The digital radio service provides better quality sound to receiver and uses frequency efficiently. However, digital radio has the potential to cause interference problem, since in-band digital radio systems occupy existing analog radio frequency bands. It is important to effectively analyze this interference for both digital radio receivers and analog radio receivers. This paper analyzes the interference between the DRM+ system used in in-band digital radio and the existing analog FM system, and derives the optimal separation distance needed to preclude interference. These results are able to supply basic information for digital radio system cell design.

Optimal Path Search Algorithm for Urban Applying Received Signal Strength on Satellite Communication Environment

In this paper, we propose an optimal path search algorithm that applies the received signal strength between a mobile device and a satellite. Because the common path search algorithm is only based on the shortest path search, it is difficult to provide stable multimedia services for the satellite mobile devices. The proposed algorithm provides the stable communication environment for the satellite mobile devices based on received signal strength. In Satellite communications, changes in the radio quality are severe depending on the receiving environment. Therefore, an accurate analysis of the receiving environment characteristics is very important for providing stable multimedia services of satellite communications. The causes of radio attenuation are atmosphere attenuation, vegetation attenuation and buildings attenuation. These factors were applied to analyze the received signal strength. The proposed algorithm can search the optimal path in urban for stable satellite multimedia services.

Interference Analysis of Digital HD Radio System considering Angular Effect

In the current wireless communication technology, the digital radio system replaces the analog radio broadcasting. Since the in-band digital radio systems are used in the existing analog radio frequency band, interference problems of digital radio are caused. It is important to effectively analyze the interference. In this paper, to analyze SINR and BEP (bit error probability) of digital radio system, we propose the analysis method considering angular effect. The angular effect means a method to analyze the interference when the receiver is located in different directions around the transmitter. These results are able to give basic information for the allocation of digital radio networks.

Development of MAC Function for the Spectrum Sensing based on Cognitive Radio

The worth of frequency resources is growing up because of development of wireless communication. However, frequency resources is short, because demand is much more than supply. So it needs Cognitive Radio(CR), which manages frequency resources efficiently. In this paper, we apply the efficient Spectrum Sensing method based on CR in an embedded board. We examine various Spectrum Sensing methods and apply these methods to an embedded platform on CR environment and verify the performance through the MAC message.

Propagation Characteristics Analysis for an Urban Site of Geostationary Earth Orbit Satellite using Ka-band

In satellite communication system, propagation characteristics analysis of the receiving environment is very important, because radio quality is changed by the receiving environment. Unlike Terrestrial wireless communications, satellite communication is affected by altitude and atmospheric environment. Therefore, there are many factors to consider for propagation characteristics analysis. In this paper, signal reception environment of geostationary earth orbit was analyzed on urban environment. In order to analyze the propagation simulation, virtual buildings was established and reception environment was changed. The results of this paper would help to design the satellite mobile communication systems in Ka-band.

Radio Propagation Analysis for Various Urban Sites on Ka-Band Satellite Communication

Propagation analysis of the transmitting and receiving environment is important for designing satellite communication systems. The satellite signal passes though the atmospheric layer and is affected by the resulting attenuation. Therefore, systematic analyses of the atmospheric characteristics and the receiving environment are needed. This study examined the propagation characteristics of a geostationary satellite using the Ka band. The atmospheric characteristics of the Ka band were analyzed, and the urban environment was modeled. A range of receiving environments was analyzed. The results of this paper are expected to assist in the design of satellite mobile communication systems in the Ka-band.