• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1449-1454
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• 2012

Received signal strength indicator (RSSI) represents the strength of the received signal at the front end of analog-to-digital convertor (ADC) input. RSSI value can be used for deciding the status of channel at the receiver. In this paper, the usage of RSSI in handover is studied using the practical measurement data. We first measure RSSI in 5.9GHz frequency band which is commonly used in wireless access in vehicular environments (WAVE) system. i.e., vehicular communications. Then, to implement a fast handover, the usability of RSSI data is analyzed based on the measured data. We also apply handover in practical highway environments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.541-546
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• 2006

Zigbee를 이용한 실내 위치 측정 기법에서는 수신신호세기(RSSI) 측정치를 거리측정치로 활용하여 삼각측량법이나 DB 검색법을 이용하여 위치를 구한다. RSSI 측정치는 Zigbee 통신에서 기본적으로 제공하는 값으로 하드웨어 추가 없이 거리 측정에 사용할 수 있지만 정확도가 떨어진다. 이를 해결하기 위해 초음파 센서를 장착하고 RF와 초음파의 속도차이를 이용하여 정확한 거리를 측정할 수 있다. 이렇게 구해진 거리를 이용하면 정확한 위치를 구할 수 있다. 이를 구현하는 방법으로 본 논문에서는 고정된 위치의 비컨들이 순차적으로 신호를 전송하여 노드의 위치를 구하는 경우 발생하는 비컨의 전송 스케줄, 추가 및 동기 유지의 어려움을 해결할 수 있도록 노드에서 신호를 전송하고 비컨에서 구한 거리를 다시 노드로 Zigbee 통신을 이용하여 전달하여 위치를 구하는 기법을 제시하였다. 추가로 본 논문에서는 비컨 수의 제약으로 위치를 구할 수 없는 경우에 초음파 측정치에 추가하여 RSSI 측정치를 동시에 이용하는 위치측정기법을 제시하고, 실제 정적, 동적 실험을 통하여 그 유용성을 보였다. 3개 이상의 초음파 신호가 수신되는 경우 cm 급의 정확도로 위치를 10Hz 이상으로 구할 수 있었으며, 2개 이하의 초음파 신호가 수신되는 경우에도 RSSI 측정치가 있으면 수십 cm 급의 정확도로 위치를 구할 수 있음을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.875-878
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• 2010

In this paper, we proposed a RSSI based cooperative localization algorithm considering wireless propagation characteristics in indoor environment for wireless sensor networks, which can estimate the BN position. The conventional RSSI based estimation scheme has low precision ranging according to time variable propagation characteristics. Hence, we implemented ray-launching simulator for analysis of propagation characteristics in $13.65m{\times}8.7m$, and performed proposed localization scheme with 4 RN and 1 to 5 BN. From the results, if we can consider channal characteristic in proposed ranging scheme, the cooperative localization algorithm with propagation characteristics provides higher localization accuracy than RSSI based conventional one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1511-1519
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• 2010

In this paper, we proposed and analyzed a RSSI based cooperative localization algorithm considering wireless propagation characteristics in indoor and outdoor environments for wireless sensor networks, which can estimate the BN position. The conventional RSSI based estimation scheme has low precision ranging due to instability propagation characteristics by time variable. Hence, we implemented ray-launching simulator for analysis of propagation characteristics in 4 case, and experimented proposed localization scheme with 4 RN and 1 to 5 BN. Simulation results show that NLCA has estimation error as 2m-3.5m, however, proposed CLA/ECLA has 1.3m-2.5m/0.5m-1.2m by same environments. Therefore, if we can consider channel characteristics, the proposed algorithm provides higher localization accuracy than RSSI based conventional one.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.90-94
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• 2014

This paper suggests the system that allows nearby firefighters to read about the transmission direction of a distress signal and track the location by RSSI of received distress signal which is transmitted wirelessly after sensing the distress signal of a firefighter using the Wireless Sensor Network(WSN) based on IEEE 802.15.4 and Received Signal Strength Indicator(RSSI) in the building. Also, It was confirmed that the location tracking using RSSI is possible because the difference between theoretical value and experimental value is little when experiment using the proposed system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.181-188
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• 2013

In this paper, we present a system design for location determination inside the ship. Since the GPS signal can not be received in the interior of the large vessel, we use the vessel wireless AP (Access Point) RSSI (received signal strength indication) to accurately measure the position. We convert the RSSI for the 3 AP's into distance through the Friis formula and get the location through triangulation. The signal strength varies irregularly due to noise making it difficult to obtain the exact location. Thus Kalman filter is used to real-time position correction, that is store in a server database.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.162-164
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• 2009

IEEE 802.15.4에서 채널 간 충돌을 회피하기 위해 제안된 CSMA/CA 알고리듬은 수신되는 신호의 상관관계를 나타내는 지표인 LQI (Link Quality Indicator) 값과 수신되는 신호의 크기를 나타내는 지표인 RSSI (Received Signal Strength Indicator) 값을 이용한다. 지그비 모듈에서 측정되는 LQI 값은 수신되는 신호의 크기에 따라 변화하는데, 그 상관관계가 매우 부정확한 문제가 있어 왔다. 본 논문에서는 CC2430과 CC2591을 이용해 제작된 지그비 모듈을 기반으로 수신 신호의 크기와 LQI 값을 실험적으로 측정하여 RSSI 값에 따른 LQI 값의 상관관계를 분석하였다.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.604-613
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• 2018

In this study, we analyzed the variations in the received signal strength index (RSSI) measured from Bluetooth beacons based on the strength and propagation direction of Bluetooth low energy (BLE) signal. Using a smartphone, we performed field experiments to investigate RSSI variations in the BLE signal transmitted by non-directional and directional beacons in an amethyst mine. In case of non-directional beacons, as the distance between the Bluetooth beacon and smartphone decreased, the RSSI increases, whereas as the BLE signal strength increased, the RSSI average gradually increased. The mean value of RSSI measured from the directional beacons was changed without relation to the facing angle between the Bluetooth beacon and smartphone. The results of this study can be used as basic data for developing a Bluetooth beacon-based proximity warning system for underground mines.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.999-1004
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• 2010

Most of campus vehicle management systems, so far, simply manages coming in or go out of vehicles, issuing a parking tickets. Recently some of them use RFID tags to count total numbers of cars in the campus, excluding exact parking position management. In this paper we propose a new campus vehicle management system using wireless sensor network location management scheme. This system adopts RSSI based location management method with some performance improvement technique. According to the experimental result, this proposed scheme can be used to implement an effective campus vehicle management system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.179-182
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• 2006

WSN에서 위치를 구하는 방법으로 WLSQ와 DB를 이용하는 방법이 대표적이다. WLSQ에서는 수신된 RSSI로부터 거리를 구하고 구해진 거리를 이용하여 위치를 구하며, 구해진 위치의 정확도는 측정된 RSSI의 정확도와 이로부터 거리를 구하는 알고리즘에 좌우된다. DB를 이용하는 기법은 DB를 구축하는 방법과 측정된 RSSI와 DB를 비교하는 기법에 따라 정확도가 결정된다. 본 논문에서는 수신된 RSSI와 DB를 비교하여 위치를 구하는 기법의 구현 및 성능을 나타내었으며, WLSQ의 결과와 비교하였다.