Yan-Ming Cheng

Analysis on Interference Impact of WiFi on DTV

TV White Spaces (TVWS) are freed up when transition from analog television to Digital Television (DTV). Some wireless communications are allowable to operate in TVWSs, such unlicensed Wireless Fidelity (WiFi). Because TVWSs are located in the VHF and UHF bands, TVWSs can provide significantly better coverage and wall penetration inside buildings and other structures than the 2.4GHz and 5GHz WiFi frequencies currently in use. Therefore, this paper assumes that WiFi will be deployed in TVWSs. However, the interference impact of WiFi on DTV has to be taken into account. The interference probability in DTV receiver was evaluated by using Spectrum Engineering Advanced Monte-Carlo Analysis Tool (SEAMCAT). As results, if the interference probability of 5% is acceptable to DTV receiver, when 20 WiFi UEs are simultaneously operating at the maximum transmit power of 23 dBm and the guard band is 22 MHz, the protection distance should be at least 6 km.

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

Analysis on the interference of UWB sensor into WiBro in Korea

This paper presents the interference of Ultra Wide-Band (UWB) sensor applied in Korea into Wireless Broad-band (WiBro) system based on Orthogonal Frequency Division Multiplexing (OFDM) using frequency of 2.3 GHz. The Minimum Coupling Loss (MCL) method and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) are used to evaluate the interference effects of UWB sensor on WiBro. The required minimum allowable distance is determined by MCL method should be 0.15 m when UWB sensor power spectral density (PSD) is −86.4 dBm/MHz in the case of single interferer in indoor environment. For the case of multiple interferers in outdoor environment, when number of active transmitters is 94, SEAMCAT is used to figure out UWB sensor PSD of −89 dBm/MHz below should be required to avoid the interference probability occurring in WiBro mobile station.

Interference of DTV into radio microphones in Korea

Recently, Korea has made a plan to allocate CH 14∼ CH 51 (470 MHz–698 MHz) for DTV. Therefore, it is necessary to take into account compatibility and sharing between DTV and other potential service systems. This paper assumes that DTV operates on CH 51 (692 MHz∼ 698 MHz) and radio microphones operate on CH 52 (698 MHz∼704 MHz) in spare band, and then analyzes compatibility between DTV and radio microphones. According to interference scenarios, protection requirements and system parameters, in the case of DTV potentially interferes with radio microphone, in the worst case, Minimum Coupling Loss (MCL) methods is used to determine that the required protection distance between DTV and radio microphone should be more than 1710.6 m for indoor scenario and 168.1 km for outdoor scenario; and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) is used to determine that the guard band between DTV and radio microphone is 2.4 MHz for indoor scenario and 2.9 MHz for outdoor scenario. The analysis results may offer a reference and be helpful for considering compatibility between DTV and radio microphones before DTV will be used.