什么是RP1？

RP1是OBSAI（Open Base Station Architecture Initiative）引入的概念。

https://en.wikipedia.org/wiki/Open_Base_Station_Architecture_Initiative

OBSAI架构中，BTS的结构分为四块：

•  Radio Frequency (RF) block：sends and receives signals to/from portable devices (via the air interface) and converts between digital data and antenna signal. Some of the main functions are D/A and A/D conversion, up/down conversion, carrier selection, linear power amplification, diversity transmit and receive, RF combining and RF filtering.
•  Baseband block ：processes the baseband signal. The functions include encoding/decoding, ciphering/deciphering, frequency hopping (GSM), spreading and Rake receiver (WCDMA), MAC (WiMAX), protocol frame processing, MIMO etc.
• Control and Clock block ：between these three blocks is maintained by the Control and Clock Block.
• Transport block：interfaces to external network, and provides functions such as QoS, security functions and synchronization.

Internal interfaces:

Internal interfaces between the functional blocks are called reference points (RP).

RP1 is the interface that allows communication between the control block and the other three blocks. It includes control and clock signals. RP1 specification also specifies UDPCP - a UDP based reliable communication protocol. A version 2.1 of the reference point 1 interface was published in 2008.[2]

RP2 provides a link between the transport and baseband blocks. Version 2.1 of the reference point 2 interface was published in 2008.[3]

RP3 is the interface between baseband block and RF block. RP3-01 is an (alternate) interface between Local Converter and Remote RF block. Version 4.2 of the reference point 3 interface was published in 2010.[4]

RP4 provides the DC power interface between the internal modules and DC power sources. Version 1.1 of the reference point 4 interface was published in 2010.[5]

Most of the industry at the time revolved around achieving lower cost RF modules and power amplifiers (PA), as these two components usually account for nearly 50 percent of the BTS cost. Consequently, OBSAI works to define reference point 3 (RP3) prior to the other reference points to promote more competitive sources in the RF module and PA market.