DAS solutions fed by CPRI have been proven to improve performance and reduce overall cost when compared to DAS architectures that are based on traditional RF.
What is CPRI?
CPRI stands for Common Public Radio Interface. It is a wireless communications network specification that is still evolving. It is defined by a group of OEMs and addresses the communication link between the radio equipment, known as remote radio units (RRUs) and radio equipment controller units, commonly called baseband units (BBUs).
CPRI is however not a standard, as it only defines the critical conditions for connectivity, control communications and interfacing transport between BBUs and RRUs. Radio equipment OEMs adhere to the framework, but encode their own unique version of the specification to deliver processing efficiencies that is unique to their own hardware.
System vendors in the distributed antenna system (DAS) space have traditionally not been able to use the CPRI protocol to interface base station systems directly with their equipment. The DAS interface instead had to use remote radio heads for amplification, analog radio frequency (RF) processing, complex cabling networks and stacks of signal manipulation panels. The connections between these passive and active network elements often resulted in errors and loss of communication between the DAS inputs and the BBUs.
There's however now a direct digital optical link available from the DAS to the BBU with CPRI. This digital interface is direct and removes the need for redundant RF conditioning and processing. DAS solutions that are fed by CPRI have been proven to be simple to install, improve performance and reduce overall cost when compared to DAS architectures that are based on traditional RF.
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