• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2015-2021
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• 2017

Recently, a lot of attention is fallen to IoT(Internet of Things) for hyper-connected society and the number of unlicensed wireless device has been increasing. Thus, this paper analyzed the impact of unlicensed wireless device on the basis of 802.11ah on licensed LTE user equipment in 900 MHz frequency band for efficient frequency use. As the interference analysis method, Minimum Coupling Loss (MCL) method and Monte Carlo (MC) method were used. In case of one interferer, minimum separation distance between interferer and victim was calculated as about 22 m through the MCL method under the assumption of the worst case. The maximum number of interferer to meet the interference probability of 5% below within a cell radius of the victim was computed as about 3000 by using MC method based on statistical technique. The analysis method and results in this paper are expected to be used for the coexistence between unlicensed wireless device and licensed wireless device.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.95-100
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• 2011

This paper analyzes the interference effect of WLAN(Wireless Local Area Network) service on WiBro(Wireless Broadband) service in adjacent frequency band by using Monte Carlo method. For the analysis, we make scenario that WLAN service operates on frequency band of 2401 MHz ~ 2423 MHz and WiBro service operates on frequency band of 698 MHz ~ 704 MHz. In case of WiBro receiver is close to WLAN AP(Access Point), the interference will be increased. So, we calculate the protection distance between WiBro receiver and WLAN AP to meet interference probability of 5 % below and required interference power of WLAN AP to meet interference probability of 5 % below in the case of fixed protection distance. As a result, the protection distance of 60 m and -9.5 dBm of required interference power of WLAN AP at 10 m of the fixed protection distance are analyzed.

• Electronics and Telecommunications Trends
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• v.21 no.6 s.102
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• pp.202-211
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• 2006

본 논문에서는 2.4GHz 마그네트론을 이용하는 RF 전구에 대하여 동 대역을 사용하는IEEE 802.11b 기반의 무선랜과 전파간섭을 분석하였다. RF 전구가 무선랜에 미치는 전파간섭을 분석한 결과, LOS 환경(무선랜 수신전력 -63dBm/MHz)에서는 무선랜 채널 9, 10에 약 1~2Mbps의 전송속도 저하를 유발하였으며, Non-LOS 환경(무선랜 수신전력 -78dBm/MHz)에서는 무선랜 채널 6-11번에 통화절단 현상을 야기하였다. 그러나, RF 전구 수에 따른 간섭전력의 누적효과는 없는 것으로 나타났다.

• Information and Communications Magazine
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• v.31 no.8
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• pp.84-91
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• 2014

본고에서는 최근 학계 및 산업계에서 활발히 연구되고 있는 간섭정렬 기술동향에 대해 소개한다. 특히 Signal Space 간섭정렬, Signal Scale 간섭정렬, Ergodic 간섭정렬의 기본 개념과 장단점 및 응용분야를 정리하였다. 또한 셀룰라 무선망에서의 간섭정렬에 대해 소개한다. 크게 단일안테나 환경과 다중안테나 환경에서의 간섭정렬로 나뉠 수 있으며, 각각의 경우에 대해 기술동향 및 주요 연구결과를 정리하였다. 마지막으로 최근 Reverse TDD, 즉 상향링크와 하향링크가 공존하는 환경에서의 간섭정렬을 통해 다중안테나 셀룰라 무선망의 자유도를 획기적으로 개선 할 수 있는 연구결과를 소개한다.

• Journal of Internet Computing and Services
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• v.16 no.6
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• pp.1-9
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• 2015

In this paper, we study the coexistence of typical radio access technologies (WiMAX, CDMA, WLAN) in heterogeneous networks. Although the radio accesses employ different frequency band, they can interfere with each other due to out-of- band emission. We compute the minimum adjacent channel interference ratio (ACIR) to satisfy the allowable level of interference, and the resulting minimum frequency separation (guard band) between interfering and victim system. We observe that WiMAX-WLAN coexistence and WiMAX-CDMA coexistence are feasible with at least 20 MHz and 15 MHz guard bands, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.609-610
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• 2017

Cognitive radio communication techniques have been attracting attention to efficiently use the scarce spectrum as the wireless communication service increases. In cognitive radio communication, efforts to minimize interference to the primary user are important technical factors. In a multi-hop wireless ad hoc network, multi-hop transmission requires path and channel selection considering channel interference as well as collision with primary users. In the multi-channel environment, cognitive radio network has different capacities depending on the inter-channel interference and collision with the main users. In this paper, we propose a multi-hop transmission scheme that minimizes inter-channel interference and reduce collision with primary users.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.52-57
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• 2012

We propose a weighted time-reversal prefilter for indoor wireless communication systems. In the indoor wireless communication environments, the bit error rate (BER) performance is significantly degraded by the delay spread. The conventional schemes have complex receivers to recover deterioration of the BER. The proposed time-reversal prefilter simplifies the structure of receivers, minimizes the inter-symbol interference (ISI) and maintains the peak power level of the received signal. The simulation results show that the weighted time-reversal prefilter improves the BER performance in comparison with the conventional time-reversal prefilter.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.481-486
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• 2022

The recent rapid growth of the IoT(Internet of Things) is leading to the spread of low-power wireless technology. A major challenge in designing IoT wireless networks is to achieve coexistence between different wireless technologies that share the 2.4 [GHz] ISM (Industrial Scientific Medical) frequency band. Therefore, there is a need for research on improving the reliability of wireless networks and coexisting operation between wireless networks. In particular, it is necessary to study an interference model and performance for mutual service coexistence in a BLE (Bluetooth Low Energy) wireless network environment, which is expected to be widely used as a connection medium between devices in various industrial fields. In this paper, the co-channel interference model with the IEEE 802.15.4 system is established focusing on the physical layer of the BLE system widely used in residential and industrial wireless applications, and the performance of the BLE wireless communication system is analyzed in the co-channel interference environment. As a result of the analysis, as the distance between the interference source and the BLE system increases in an environment where noise and co-channel interference exist, the amount of co-channel interference decreases and the error rate performance of the BLE system improves.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.47-52
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• 2014

Recently, the interest of Wireless Power Transmission(WPT) has been increased for Mobile device application. It is necessary to analyze interference between wireless devices for the efficient use of frequency resource. The Minimum Coupling Loss(MCL) method and the Monte Carlo(MC) method were used for the interference analysis. In this paper, the impact of the 3rd order harmonics of the wireless charger for Cellular Phone on the existing Radio Modem was analyzed. As a result, the separation distance and the allowable number of interferer on the basis of service radius were obtained to protect the Radio Modem from the wireless charger for Cellular Phone.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.259-266
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• 2017

The massive traffic interferences in the wireless home IoT provides the reason for packet losses, and it degrades the QoS (Quality of Service) and throughput on the home network. This paper propose a new adaptive traffic interference control system, ATICS, for enhancing QoS and throughput for IoT services as detecting a traffic process and non-traffic process in the wireless home network. The proposed system control the traffic interferences as distinguishing the short-term traffic process and long-term traffic process by traffic characteristics in wireless home networks. The simulation results shows that the proposed scheme have more efficient traffic control performance than the other schemes.