Agilent Solutions for Millimeter Wave Wireless Backhaul - Application Note 5991-3788EN c20140612 [6] free download

File name Solutions for Millimeter Wave Wireless Backhaul - Application Note 5991-3788EN c20140612 [6].pdf

Keysight Technologies Solutions for Millimeter Wave Wireless Backhaul Designing and Testing E-Band Backhaul Using Effective Network Analysis, and Signal Generation and Analysis Solutions Application Note Overview The backhaul plays a critical role in the telecommunications network, comprising the intermediate links between the core, or backbone network, and the small subnet- works at the edge of the entire network. In microwave mobile or wireless networks, there are three types of backhauls: macrocell, small cell and femtocell. Femtocell backhauls normally use a broadband access technology and are not covered in this application note. Small cell backhauls transport traffic between the outdoor small cell site and either the node connecting to a macrocell backhaul network, or the node connecting to the Wide Area Network (WAN)/Internet/metro network. It comprises equipment at both ends, along with any mesh or serial equipment in between. Today, operators have a number of different backhaul technologies to choose from, one of which is called E-band. It presents a particularly enviable option due to its high capacity and potential economic benefits. Available worldwide, E-band point- to-point, line-of-sight microwave radios--also known as millimeter wave (mmWave) radios--operate in the unlicensed 57-64 GHz frequency band at data rates up to 1 Gbps, and in the lightly licensed 71-86 GHz frequency band and 92-95 GHz frequency band at data rates up to 10 Gbps. Such functionality makes them ideal for dense urban environments (less than 1 km), as well as, industrial suburban environ- ments (2-5 km). And, it's a key reason why analysts project a significant jump in the mmWave backhaul market in coming years, driven largely by the increased use of mmWave for Long Term Evolution (LTE) small cell backhauls. Problem There are a number of reasons why today's operators might want to migrate to an E-band backhaul. Such solutions offer more bandwidth in higher frequency bands and feature an antenna beam that is very directional and easy to control. Additionally, the frequency bands in which E-band radios operate, namely 60 GHz and 70-90 GHz, are now open to commercial services and products. Despite these advantages, there are also a number of design and test challenges that can be expected as this transition occurs. For example, the extremely narrow beam width of E-band leaves the signal potentially vulnerable to building sway and atmospheric interference. It also makes aligning systems very difficult. And, E-band is very susceptible to degraded performance caused by the rain and oxygen absorp- tion. The rain essentially interferes with the E-band's radio wave transmission, forcing it to repeatedly transmit data to achie