• Journal of the Korean Institute of Navigation
• /
• v.24 no.5
• /
• pp.405-415
• /
• 2000

DGPS/Radio beacons are currently being planned or installed in many countries. They offer a cost-effective way of distributing differential data to large number of users. These networks are also being deployed in South Korea, Japan, and China. Several DGPS stations among them are operating on the same frequencies. The DGPS signal based on a radio beacon in medium frequency band travels principally as a groundwave over the surface of the earth. The signal may also be received as skywaves at locations beyond about 100 km from the reference station. These skywaves interfere with groundwave signals due to fading. This factor has generally ignored in designing DGPS/Radio beacon systems. A further important factor is to reduce the coverage due to interference from other beacons on the same or adjacent frequencies. The desired signal may fade due to interaction between its skywave and groundwave components. It may degrade the accuracy of the positioning in a complex fashion. This paper estimates the coverage of Far East Asia DGPS stations which are operating on the same frequencies, which is based on the signal protection ratio and interference of the signal strength of the groundwave and skywave.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.491-494
• /
• 2018

Radio base stations, which are widely distributed across large areas, have many difficulties in managing them. Unmanned radio base stations in remote mountains are having a hard time accessing them in case of emergencies. Major telephone service providers only remotely control incoming and outgoing information and local small business partners responsible for maintaining actual facilities do not possess such technologies, so they are each checked during field visits. In this study, in order to monitor temperature, humidity, fire condition, and power operation at a wide range of radio base stations, real-time monitoring is carried out at the office of Klaus server through real-time monitoring.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.2
• /
• pp.196-208
• /
• 2002

Since radio interference has occurred in the TRS frequency band in the south coastal area, Korea from 1994, similar interference has been observed in the mobile-cellular frequency band. Measurement showed that the sources of the radio interference are those from the base stations for digital cellular systems in Japan. This because the receiving frequency of the base stations in Korea is same as the transmitting frequency of the base stations in Japan. Since the distance between Korea and Japan is 240 ~ 300 km, we can conclude that the main reason of the interference is ducting. In this paper a ducting channel is modeled by split-step DMFT algorithm, and simulation results for measured index profile far east coast and west sea area are analyzed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2011.11a
• /
• pp.295-296
• /
• 2011

The DRM+ is the newest digital radio standard for in-band environment. Although various state of the art technologies are adopted, the performance evaluation information is not sufficient. It is hard that many countries and stations considering the DRM+ as their digital radio standard check the performance of DRM+. To evaluate the performance of the DRM+ system, this paper depicts the laboratory trial results of DRM+ standard. In the laboratory trial, the rack type DRM+ test bed is built. To reflect the practical broadcasting environment, various tests are executed. Many countries and stations can efficiently use these test results, which are considering converting their analog radio broadcasting to digital broadcasting.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.6
• /
• pp.1145-1154
• /
• 2018

In order to prevent interference and interference of the frequency, it is required to convert the regulatory standard into the center of the radiation power radiated to the actual public. Since the radiation power regulation is related to general radio management such as technical standards, permits, and inspections, it is gradually introduced in consideration of applicability and urgency, and the radiation power related laws of major countries And a method of controlling the output of the radio equipment such as measurement, inspection, and authentication. In Korea, the proportion of antenna power supply is high, and in Europe, radiation power is high. Since the number of radio stations will increase and diversify in the future, institutional improvement should be made so that it can be measured in parallel with the radiocommunication infrastructure of the space manager. In order to convert to the radiative power management system, the system for the related radio system needs(Technical standards, certification, inspection of radio stations, post-management, etc.) to be improved.

• KIPS Transactions on Computer and Communication Systems
• /
• v.5 no.5
• /
• pp.103-108
• /
• 2016

In this paper, we propose a resource allocation scheme that guarantees transmission rate for each mobile stations by mitigating interference between a base station-to-mobile station link and a relay station-to-mobile station link. Specifically, we dynamically adjust the boundary between access zone and relay zone using signal to interference plus noise ratio. Moreover, we cluster the mobile stations under sever interference and manage the channel quality of these mobile stations by allocating additional radio resource. Our simulation results show that the proposed scheme can improve the efficiency of radio resources and ensure fairness among mobile stations.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.576-580
• /
• 2003

In order to assess the spectrum usage efficiency in mobile radio services, we consider the capacity limits of a CDMA system. The maximum achievable capacity per $km^2$ is viewed as a meaningful figure of merit for a cellular system and a method is proposed here to estimate the minimum achievable distance between adjacent base stations in the case of CDMA. The probability for entering in soft handover state is used as a limit for densification in a CDMA system. From this criterion, conditions on the minimum possible cell radius are derived.

• Journal of Satellite, Information and Communications
• /
• v.1 no.2
• /
• pp.8-15
• /
• 2006

Under Resolution 122 (Rev. WRC-03), ITU-R is invited to study, as a matter of urgency, power limitations applicable for HAPS ground stations to facilitate sharing with space station receivers in the bands 47.2-47.5 GHz and 47.9-48.2 GHz. However, there have been no studies on this issue. Recommendation ITU-R SF.1481-1 which was developed during past study period, provides methodology and system characteristics for analyzing the sharing feasibility between systems in the FS using HAPS and systems in the FSS. System characteristics for a typical HAPS in the bands above are also given in Recommendation ITU-R F.1500. This paper provides the results on power limitations applicable for HAPS ground stations in accordance with Resolution 122 (Rev. WRC-03). As already shown in ITU-R Recommendation the results show that a sufficient separation distance is required for sharing between HAPS ground stations and FSS satellite systems. We obtain some examples of the sharing conditions considering reducing the power level of HAPS ground stations and using the antenna beam pattern with the low sidelobe to decrease the interference level affecting FSS satellite receiver.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.10b
• /
• pp.29-35
• /
• 2000

As the increasing demand of the radio wave communication and teh progreessing of communication system, the radio interference of neighbor nations is rising in the improtant matter. This problem is a delicate matter which must be dealt diplomatically with by having a distinct technical basis. For our country, after the radio interference has been occurred in TRS service on the south seashore due to the base stations located at Fukuoka in Japan, the radio interference problem of neighbor nations has risen importantly. In this paper, therefore, we has measured the radio wave that reach from Fukuoka in Japan to Pusan in Korea and also collected dat by real-time.

• Journal of Korean Society for Quality Management
• /
• v.51 no.4
• /
• pp.515-530
• /
• 2023

Purpose : This research aims to develop a data-driven inspection policy for radio stations utilizing the KS Q ISO 2859-1 sampling method, addressing potential regulatory relaxations and impending management challenges. Methods : Using radio station inspection big data from the past six years, we established a simulation model to evaluate the current policy. A new inspection sampling policy framework was designed based on the KS Q ISO 2859-1 method. The study compares the performance of the current and proposed inspection systems, offering insights for an improved inspection strategy. Results : This study introduced a simulation model for inspection system based on the KS Q ISO 2859-1 sampling method. Through various experimental designs, key performance indicators such as non-detection rate and sample proportion were derived, providing foundational data for the new inspection policy. Conclusion : Using big data from radio station inspections, we evaluated current inspection systems and quantitatively compared a new system across diverse scenarios. Our simulation model effectively verified the feasibility and efficiency of the proposed framework. For practical implementation, essential factors such as lot size, inspection cycle, and AQL standards need precise definition and consideration. Enhancing radio station inspections requires a policy-driven approach that factors in socio-economic impacts and solicits feedback from industry participants. Future study should also explore various perspectives related to legislative, institutional, and operational aspects of inspection organizations.