UHF RFID與GSM900干擾測試分析

UHF RFID是近年來，新興的無線電器材，在美國地區，FCC所規劃的頻段是屬於ISM(工業、科學、醫療)頻段，頻段由902MHz至928MHz。在台灣上述頻段與現存GSM900通信業務所用頻段有部份重疊，因此政府已規範在台灣地區RFID之使用頻段須限制在922MHz至928MHz之間，且發射功率也限制於1W以下。即使政府已有規範，但GSM900通信業者仍恐其通信系統有受RFID鄰頻干擾之虞，本論文安排於實驗室內檢測RFID設備器材，確認RFID器材之發射功率及頻率範圍是否符合「低功率射頻電機技術規範」以及安排RFID設備於室內微細胞GSM基地台旁運作時，檢測UHF RFID是否會干擾手機與基地台之間的上、下鏈性能，由檢測結果，得到結論及建議；諸如：RFID設備與微細胞GSM900系統兩者使用時，宜保持間距2米以上，且兩者之天線方向宜避開相對，則可避免互相干擾。另於檢測中，我們也發現在室內微細胞GSM900系統的下鏈性能確實較易受干擾，若發生受RFID干擾，則下鏈性能會更差，最後，本論文也建議使用RFID設備時，須謹慎使用勿干擾既有的GSM900行動通信系統，俾兩者能和平共處。

關鍵字

低功率射頻電機技術規範

並列摘要

UHF RFID is a newly developed wireless electronic instrument in recent years. The allocation frequency band assigned by FCC in the district of America ranges from 902 MHz to 928 MHz. In Taiwan, this band overlaps partially with currently existing GSM900 used in the communication area. Therefore, our government has already passed regulations to restrict the usage of frequencies by RFID in Taiwan district between 922 MHz and 928MHz, and the radiating power is limited to below 1W. Even though there are government regulations, the GSM communication industry still fears that its communication system may be interfered by adjacent channels from RFID. This thesis is devoted to have measurements to see whether the interference has any significant effect on existing channels. The measurement is implemented by placing RFID equipment indoors and next to a micro-cell base station of GSM inside a building. We evaluate whether or not the UHF RFID will interfere uplink and downlink between the handset and the base station during operation. Through measurement, we found that downlink of the micro- cell is more likely to be disrupted. As for up-link, no significant interference is observed. When both the RFID equipment and micro cell GSM900 system are in use, there should be a distance of at least 2 meters to be kept between them, and their antennas should also be positioned in opposite direction to avoid mutual interferences.