TC Pool

Hello, GuiDance.

Huawei GSM base station subsystem allows multiple BSCs to connect to the transcoder subracks (TCSs) of another BSC so that these BSCs can share transcoding (TC) resources. In this manner, the TCSs form a TC pool.

l The TC Pool feature is determined by the IsSupportTcPool parameter.

l The TC Pool feature applies only to the BSCs whose ServiceMode is set to SEPARATE(Separate). When ServiceMode is set to SEPARATE(Separate), the TC resources exist in the remote TCSs.

Without the TC Pool feature, TCSs independently process circuit switched (CS) services for their respective BSCs. TC resources cannot be shared among BSCs. This leads to a waste of TC resources, especially in scenarios where multiple BSCs with small capacity are deployed in a network.

With the TC Pool feature, one to four TCSs of the primary BSC form a TC pool. TC resources in the TC pool are shared among the primary and secondary BSCs, which work in load sharing mode, as shown in Figure 2-1.

Figure 2-1 Allocation of TC resources in a TC pool

Figure 2-2 shows a typical network topology for a TC pool. In Figure 2-2, the primary and secondary BSCs connect to the TC pool over the Ater interface, and the TC pool connects to the MSC over the A interface.

Figure 2-2 Typical network topology for a TC pool

The primary and secondary BSCs are described as follows:

l The primary BSC configures and maintains TC resources in a TC pool and a TC pool has only one primary BSC. The TCSs in a TC pool belong to the primary BSC.

l The secondary BSCs, configured with only Basic Module (BM) subracks, share TC resources with the primary BSC. The Main Processing Subrack (MPS) and Extended Processing Subrack (EPS) are collectively called BM subracks.

The TC Pool feature brings the following benefits:

l Flexible networking

This feature supports the E1/T1 and Ch-STM-1 connection modes over the Ater interface. One Ater interface board can be connected to multiple BSCs in the same connection mode.

l Low network deployment costs

This feature enables multiple BSCs with small capacity to share TC resources, greatly reducing network deployment costs.

l High network reliability

The data processing unit (DPU) boards in a TC pool work in load sharing mode, minimizing the impact of a failure in one DPU board on the entire network.

DPU boards convert and forward voice formats and perform voice coding/decoding. In this document, GSM TC Data Processing Unit REV:a (DPUa) and GSM TC Data Processing Unit REV:c (DPUc) boards are collectively referred to as DPU boards.

Thanks.