Abstract: Network investment and network quality are contradictory. As sites/equipment rooms are getting more difficult to obtain, and the leasing cost is shooting up, the construction cost and the operation cost of 3G network increase. The innovative distributed NodeB solution of Huawei can greatly reduce the leasing cost, electricity, air-conditioning, and human resource of the equipment room. According to statistics, it can save the cost of the total investment by 30%. 1 Introduction of Distributed NodeB Solution The coverage quality is critical for subscribers, operators are supposed to keep improving the network quality by installing new sites. However, the available sites and equipment room for new base stations are decreasing, and the rental fees become more expensive. How to build a network quickly and economically is the critical difficulty that the operators have to face. Distributed NodeB solution is an economical and fast wireless network deployment solution under the circumstances of no equipment room or less ideal equipment room locales. The distributed NodeB solution adopts remote RF technology. The Remote Radio Unit (RRU) can be installed near the antenna, and connected with the BaseBand Unit (BBU) via optical fiber (as shown in the following figure). The optical interface module implements clock extraction and the multiplexing/demultiplexing of the baseband signals. The I/O signals of the CPRI interface are modulated, digital/analog converted, up-converted, filtered, and amplified before they are output to the antenna feeder. CPRI is an open standard interface. In April 2003, Ericsson, Huawei, NEC, Siemens, and Nortel established the Common Public Radio Interface (CPRI) cooperation organization. The organization focuses on the new form of the WCDMA FDD NodeB, and produce new open standard interfaces, dividing NodeB into radio equipment (RE) and radio equipment control (REC). In that way, each part of the NodeB can better benefit from the technological progress from different sources.
