With the help of a diagram, discuss the RRU (Remote Radio Unit) and it’s function in radio access networks?
The RRU performs all RF functionality like transmit and receive functions, filtering, and amplification. It also contains analog-to-digital or digital-to-analog converters and up/down converters. An RRH can also provide advanced monitoring and control features that allow operators to optimize performance from a remote, centralized location.
The RRU is usually mounted near the antenna to reduce transmission line losses and is connected to the main, digital portion of the base station (BBU) with an optical fiber.
Remote Radio Unit (RRU) has two parts, a transmit part and a receive part.
The transmit part usually consists of a DAC, Mixer, Power Amplifier and Filters. A digital signal is received via a CPRI interface, converted to analog, upconverted to an RF Frequency, amplified, filtered and then sent out via an antenna.
The Receive part consists of a filter, Low Noise Amplifier, Mixer and an ADC. It receives a signal from the antenna, filters it, amplifies it, down-converts it to an IF Frequency and then converts it to a digital signal, before sending it out via the CPRI to BBU for further processing.
