5.12 Configuration of CSFB(CS Fallback)

23.0023GPPNetwork architectureRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The CS fallback in EPS enables the provisioning of voice and other CS-domain services (e.g. CS UDI video/ SMS/ LCS/ USSD) by reuse of CS infrastructure when the UE is served by E-UTRAN. This function is only available in case E-UTRAN coverage is overlapped by either GERAN coverage or UTRAN coverage.

The configurations of the CSFB entities are represented in figure 5.12.

Figure 5.12: Configuration of CSFB

NOTE: The MGW is not shown in the figure 5.12 since the CS fallback in EPS does not have any impacts to the User plane handling.