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A remote radio head is a remote radio transceiver that connects to an operator radio control panel via electrical or wireless interface. When used to describe aircraft radio cockpit radio systems, the control panel is often called the radio head. In wireless system technologies such as GSM, CDMA, UMTS, LTE this Radio equipment is remote to the BTS/NodeB/eNodeB, and is also called Remote Radio Head. The equipment will be used to extend the coverage of a BTS/NodeB/eNodeB like rural areas or tunnels. They are generally connected to the BTS/NodeB/eNodeB via a fiber optic cable using Common Public Radio Interface protocols. Remote radio heads (RRHs) have become one of the most important subsystems of today's new distributed base stations. The remote radio head contains the base station's RF circuitry plus analog-to-digital/digital-to-analog converters and up/down converters. RRHs also have operation and management processing capabilities and a standardized optical interface to connect to the rest of the base station. This will be increasingly true as LTE and WiMAX are deployed. Remote radio heads make MIMO operation easier; they increase a base station's efficiency and facilitate easier physical location for gap coverage problems. RRHs will use the latest RF component technology including GaN RF power devices and envelope tracking technology within the RRH RFPA. 〔http://www.abiresearch.com/research/product/1008995-remote-radio-heads/〕 ==RRH protection in fiber to the antenna systems== Fourth-generation (4G) and beyond infrastructure deployments will include the implementation of Fiber to the Antenna (FTTA) architecture. FTTA architecture has enabled lower power requirements, distributed antenna sites, and a reduced base station footprint than conventional tower sites. The use of FTTA will promote the separation of power and signal components from the base station and their relocation to the top of the tower mast in a Remote Radio Head (RRH). According to Telcordia industry standard (GR-3177, ) 〔(GR-3177, Generic Requirements for Remote Radio Head Protection Used in Fiber to the Antenna (FTTA) Systems,'' ) Telcordia.〕 the RRH shifts the entire high-frequency and power electronic segments from the base station to a location adjacent to the antenna. The RRH will be served by optical fiber and DC power for the optical-to-electronic conversion at the RRH. RRHs located on cell towers will require Surge Protective Devices (SPDs) to protect the system from lightning strikes and induced power surges. There is also a change in electrical overstress exposure due to the relocation of the equipment from the base station to the top of the mast. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「remote radio head」の詳細全文を読む スポンサード リンク
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