Yong-Sup Shim

Study of the throughput of WLAN according to channeling and density of AP

This study is dedicated to investigate WLAN throughput based on 802.11 data communication standard which employs 2.4GHz band, depending on its AP channels and density. In a space with high density of WLANs, throughput can be decreased due to radio wave interferences. In light of this fact, an experiment scenario has been created consisting of multiple WLANs where throughput can be measured with different combination of channels, consequently making it possible to determine more effective combination of channels. In parallel, throughput has been recorded with varying the number of APs installed within the experiment site to Fig. out the relationship between the number of APs and the throughput. According to the result of the measurement, channel 1, 5, 9, and 13 are suggested as more effective combination of channels, and declining throughput is shown as AP density increases.

A Study on Co-existence between DTV Transmitter and LTE Base Station according to DTV Transition

This paper is about frequency allocation of LTE Base Station(BS) in the spare band which is generated by DTV transition. In the case of frequency allocation of LTE BS in adjacent band with DTV channel 51 among the spare band, the guard bands that requires for no interference between LTE and DTV system were calculated. As a result, 5.5 MHz of guard band for LTE BS and 2 MHz of guard band for DTV receiver were suggested based on interference analysis between LTE BS and DTV BS, respectively.

Experiment of the Throughput of WLAN according to Channelling and Density of AP

Abstract This paper is about the experiment which is throughput of WLANs based on 802.11 due to interference each other. Recently, WLAN has been increased due to generalization of smart-phone and potable notebook. Therefore, the decrease of throughput because of interference between WLANs is expected. In regard of this, the throughput of WLANs acc-ording to channelling is measured in order to figure out efficient channelling and the throughput of WLANs according to the number of AP was measured in order to get relation between number of AP and throughput. Then, more efficint channelling of 1, 5, 9, 13 is suggested and the throughput of WLAN is decreased as increasing of number of AP. Key words : Radio Interference, WLAN, Channelling, Throughput Ⅰ . 서 론 전세계적으로유비쿼터스시대를넘어스마트시대구현을위한다양한무선서비스가개발되어상용화되고있으며, 이러한서비스의실현을위해고속의정보전송을위한광대역특성을갖는최첨단IT 및멀티미디어기기들의사용이증가하고있는추세이다 [1] . 이러한추세는새로운주파수에대한수요를증가시켜한정된주파수자원의고갈문제에직면하게되고, 이문제를해결하기위해주파수효율성을극대화하는동시에상호간에간섭을최소화하는노력이절실히요구되고있다. 최근에는, 무선랜 ⓒ Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved

Analysis of the Protection Ratio of GPS System in the Presence of RF Interference Radiated by UWB System

This paper analyzes potential interference effects of Ultra Wide Band(UWB) on Global Positioning System(GPS) which is providing safety service. For the interference analysis, positioning error method is used to determine the minimum protection distance to meet positioning error of 2.5 m below and Minimum Coupling Loss(MCL) method is used to determine the required protection ratio(I/N) from the protection distance of UWB transmitter and GPS receiver to meet positioning error of 2.5 m below. In a result, the minimum protection distance to meet positioning error of 2.5 m below was about 10 m and the protection ratio to meet positioning error 2.5 m below was -20 dB. The protection ratio proposed in this paper is the same value of the protection ratio of safety service proposed by ITU-R. The obtained protection ratio can be used for the protection standard of domestic GPS system for the safe of life service.

A Study on the Protection Ratio of GPS

GPS(Global Positioning System) service is more important than other wireless services. The GPS is necessary protected from any other interference signals. Therefore, GPS protection ratio was calculated on the basis of bit error rate(BER) in this paper. Simulation results show that the allowable maximum interference power is -190 dBm/Hz and the ratio of interference to noise(I/N) is -16 dB. The achieved protection ratio is available to be applied as the protection criteria of GPS in considering the implementation margin of 4 dB. As a result, the proposed protection ratio of GPS is expected to give standard for a stable GPS service.

Study on Coexistence between WiBro and WLAN in DTV Bands

Abstract Mutual Interference scenarios between Wireless Broadband (WiBro) and Wireless LAN (WLAN) in DTV bands are assumed. Co-channel interference and adjacent channel interference are respectively evaluated in terms of carrier to interference ratio (C/I) by using Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) based on the Monte-Carlo simulation method. For the simulation, three frequencies such as 185 MHz, 481 MHz and 687 MHz are chosen. Analysis results indicate that interference situation of using frequency of 185 MHz is the worst case, which requires longer protection distance between WiBro MS and WLAN User Equipment (UE), lower transmit power of WiBro Mobile Station (MS) and WiBro Base Station (BS) and WLAN UE and larger guard band. Comparing to cases of using frequency of 185 MHz and 481 MHz, interference situation of using frequency of 687 MHz is slighter. Therefore, using frequency of 687 MHz is easier for coexistence between WiBro and WLAN. Analysis results can be used as reference and guideline when planning the deployment of WiBro and WLAN in DTV bands.요 약