Enhanced CSFB
Systems and methods for enhanced CSFB in a mobile operator core network are described. In one embodiment, a method of wireless communication by a user equipment (UE) is disclosed, comprising: directing a UE to move from an original cell using a first radio access technology (RAT) to a second cell using a second RAT to permit a circuit switched (CS) call; terminating the CS call at the second cell; determining whether the UE should reselect to the first RAT; identifying a target cell that may be in a same location as the second cell and that uses the first RAT; and sending the identified target cell to the UE within a field in a radio resource control message.
1 . A method of wireless communication, comprising:
configuring a user equipment (UE) to send periodic measurement reports;
based on a last measurement report of the periodic measurement reports, directing the UE to move from an original cell using a first radio access technology (RAT) to a second cell using a second RAT to permit a circuit switched (CS) call;
terminating the CS call at the second cell;
identifying a target cell based on a stored association of the second cell and the target cell at a coordinating server, the stored association providing an indication that the second cell and the target cell are hosted on a single physical device;
sending the identified target cell to the UE within a field in a radio resource control message,
causing the UE to release a connection using the second RAT according to the radio resource control message; and
causing the UE to transition to the target cell according to identification of the target cell as sent to the UE in the radio resource control message,
wherein the first RAT is Long Term Evolution (LTE) or 5G, and wherein the second RAT is 2G or 3G.
2 . The method of claim 1 , wherein the radio resource control (RRC) message is a RRC CONNECTION RELEASE message according to an LTE RRC protocol.
3 . The method of claim 1 , wherein the identifying is performed at the coordinating server or the second cell.
4 . The method of claim 1 , wherein the identifying is performed based on load characteristics of the target cell.
5 . The method of claim 1 , further comprising determining that the UE should remain on the second RAT, and causing the UE to maintain a connection using the second RAT by sending the second cell as the target cell in the radio resource control message.
6 . The method of claim 1 , wherein the identifying is performed at a coordinating gateway node that is a gateway for the second cell to a core network of the second RAT and that is a gateway for the target cell for the first RAT.
7 . The method of claim 1 , wherein the load characteristics include at least one of processor load, baseband load and radio resource load.
8 . A coordinating server in a wireless network, comprising:
a processor;
a radio access network interface in communication with the processor and in communication with a plurality of multi-radio access technology (multi-RAT) base stations; and
a memory, the memory communicatively coupled with the processor, the memory further comprising instructions that, when executed by the processor, cause the coordinating server to:
configure a user equipment (UE) to send periodic measurement reports;
based on a last measurement report of the periodic measurement reports direct the UE to move from an original cell using a first radio access technology (RAT) to a second cell using a second RAT to permit a circuit switched (CS) call;
terminate the CS call at the second cell;
identify a target cell based on a stored association of the second cell and the target cell at a coordinating server, the stored association providing an indication that the second cell and the target cell are hosted on a single physical device;
send, via the second cell, the identified target cell to the UE within a field in a radio resource control message;
direct the UE to release a connection using the second RAT according to the radio resource control message; and
cause the UE to transition to the target cell according to identification of the target cell as sent to the UE in the radio resource control message,
wherein the first RAT is Long Term Evolution (LTE) or 5G, and wherein the second RAT is 2G or 3G.
9 . The coordinating server of claim 8 , wherein the coordinating server is a gateway between the plurality of multi-RAT base stations and a plurality of core networks for a plurality of RATs, and wherein the plurality of RATs includes at least 3G and 4G.
10 . The coordinating server of claim 8 , wherein the load characteristics include at least one of processor load, baseband load and radio resource load.