Node-B is a term used in UMTS to denote the BTS (base transceiver station). In contrast with GSM base stations, Node B uses WCDMA as air transport technology. As in all cellular systems, such as UMTS and GSM, Node B contains radio frequency transmitter(s) and the receiver(s) used to communicate directly with the mobiles, which move freely around it. (http://en.wikipedia.org...)