Call Processing Subsystem (CPS) in CDMA

The Call Processing Subsystem (CPS) is the hub for the BSS system’s resource management and call signaling protocol processing. The CPS contains only two modules — call processing module (CPM) and power alarm module (PAM). The CPM is connected to a port of the NIM module in the HIRS through an RS422 interface, and communicates with other subsystems in the BSC (including SVBS, BSM and the NCM module of the HIRS) and the BDS subsystem in the BTS via the HIRS.

Since the CPS does not contain many boards, it shares the same frame with the CDSU and GPSTM, as sketched in Fig

 Call Processing Module (CPM)

CPM is short for Call Processing Module. In the BSC of the CDMA WLL system, the CPM is responsible for call management. As the concentration point of SCWLL system management and signaling processing, its main functions are signaling processing of the Abis interface of the whole CDMA WLL system, wireless resource management and assignment, ground link resource management and V5 LAP data processing and V5 layer3 different protocols AN side implementation. Modularized design is employed on the hardware, and the advanced features of system realization, as well as various factors such as thermal design and electromagnetic compatibility design have been taken into consideration from the selection of components to PCB arrangement, so as to ensure board reliability. Due to the importance of the board in the whole system, the 1+1 hot backup mode is adopted. 

  Power Alarm Module (PAM)

The full name of the PAM board is Power Alarm Module. It is located in the BSC-side CDSU frame. Its main function is to monitor the running status of the power supply modules in the BSC-side frames and the equipment room environment signals, including temperature, humidity and smoke, and report the result to the background operation and maintenance console through the NCM for processing; in addition, the PAM board also provides duplex RS232 and RS485 interfaces for the connection of external monitoring devices and alarm box. 

 Channel Data Service Unit (CDSU)

In the SCWLL system, the interface between the BSC and BTS is called Abis interface. This interface links the BSC with the BTS through an E1 trunk line in the daisy chain mode. The CDSU board is the board module that implements the Abis interface functions.