Glossary
NetBlazer 603
CPRI
Functional Description
As mentioned earlier, CPRI remotely locates the RE from the REC. This
means that the RE must be controlled, managed and synchronized from
the REC in addition to transporting the User information (Voice and user
application data) and all that on the same digital link. As such, CPRI is
composed of 3 communication flows multiplexed into a single serial signal
transmitted in the same optical fiber as illustrated in the following figure.
An electrical link is also available from CPRI but it is typically used for base
station shelf interconnection. Since a state machine drives the link
parameters (rates, protocol, and C&M channel) alignment, a BTS (defined
as Master in the standard) and RRH (defined as Slave in the standard)
interfaces are defined where the Master initiates the negotiation procedure
necessary to achieve this alignment.
Synchronization: Provides precise frequency and frame timing
alignment from BTS to RRH to ensure accurate frequency and timing of
the RF signal transmission and reception on the Air Interface. In
essence, it provides the reference frequency for the RE.
Control & Management (C&M): Management of the link between the
REC and RE as well as control over radio functions such as alarms and
power.
User: Also known as IQ Data, represents the voice and data
information that is exchanged by end-User Equipment (UE)
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