Summary BSC 6900

Configuration of Subracks

The subracks of the BSC6900 are classified into the main processing subrack (MPS) and the extended processing subrack (EPS).

If the BSC6900 is deployed in the GSM network, the transcoder subrack (TCS) may exist. In this case, the MPS and EPS are collectively known as basic module (BM) subrack, and the TCS is known as TC subrack.



When the BSC6900 is deployed in the GSM network, three subrack configuration modes are

supported:



1. BM/TC separated

In BM/TC separated mode, the BSC6900 is configured with the MPS, EPS, and TCS (local or remote).

Characteristics: In this mode, the installation location of the TCS is flexible. The TCS can be installed in the transcoder rack (TCR) and be placed on the CN side, thus saving the transmission resources between the BSC6900 and the CN. Alternatively, the TCS can be installed in the same cabinet as the MPS or EPS and be placed on the BSC6900 side.



2. BM/TC combined

In BM/TC combined mode, the boards of the TCS are installed in the MPS or in the EPS,

with the subrack names unchanged.

Characteristics: The BSC6900 in this mode has higher hardware integration, and fewer

cabinets and subracks when the capacity is the same, than in the BM/TC separated mode.



3. A over IP

In A over IP mode, layer 3 (network layer) of the protocol stack on the A interface adopts

the IP protocol. In this case, the BSC6900 is configured with the MPS and EPS but not with the TCS. The TC function is performed by the Media Gateway (MGW).



Characteristics: In this mode, the BSC6900 has fewer cabinets and subracks. It must be interconnected with a specific MGW.



One BSC6900 uses only one configuration mode.

Logically, the BSC6900 consists of the following five subsystems:

3.1 Switching Subsystem (SS)

The switching subsystem performs switching of traffic data, signaling, and OM signals.

3.2 Service Processing Subsystem (SPS)

The BSC6900 service processing subsystem performs the control functions defined in the 3GPP protocols and processes services of the BSC6900.

3.3 Interface Processing Subsystem (IPS)

The interface processing subsystem provides transmission ports and resources, processes transport network messages, and enables interaction between the BSC6900 internal data and external data.

3.4 Clock Synchronization Subsystem (CSS)

The clock synchronization subsystem provides clock signals for the BSC6900, generates the RNC Frame Number (RFN), and provides reference clock signals for base stations.

3.5 OM Subsystem (OMS)

The OM subsystem enables the management and maintenance of the BSC6900 in the following scenarios: routine maintenance, emergency maintenance, upgrade, and capacity expansion.