US-20260129710-A1 - SOURCE BASE STATION AND TRANSMISSION METHOD

US20260129710A1US 20260129710 A1US20260129710 A1US 20260129710A1US-20260129710-A1

Abstract

A source base station and transmission method are provided. A source base station transmits a radio resource control reconfiguration message to a user device. The radio resource control reconfiguration message includes an indication message and a candidate base station list, and the candidate base station list is used to indicate a plurality of candidate base stations. The source base station determines a non-target base station among the candidate base stations based on a prediction report received from the user device. The source base station transmits a handover cancel request to the non-target base station among the candidate base stations to make the non-target base station release a reserved resource corresponding to the user device.

Inventors

Hsien Tsung HSU
Yu An SHAO
Wen Yao Chang

Assignees

INSTITUTE FOR INFORMATION INDUSTRY

Dates

Publication Date: 20260507
Application Date: 20241201
Priority Date: 20241106

Claims (20)

1 . A source base station, comprising: a transceiver interface, being communicatively connected to a user device and a plurality of candidate base stations; and a processor, being electrically connected to the transceiver interface, and being configured to execute the following operations: transmitting a radio resource control reconfiguration message to the user device, wherein the radio resource control reconfiguration message comprises an indication message and a candidate base station list, and the candidate base station list is configured to indicate the candidate base stations; determining a non-target base station among the candidate base stations based on a prediction report received from the user device, wherein the prediction report is generated based on the indication message; and transmitting a handover cancel request to the non-target base station among the candidate base stations to make the non-target base station release a reserved resource corresponding to the user device.
2 . The source base station of claim 1 , wherein the indication message comprises a decision indication, and the operation of determining the non-target base station further comprises the following operations: determining whether the indication message corresponds to a user device decision indication; and in response to the indication message corresponding to the user device decision indication, determining the non-target base station among the candidate base stations based on a first predicted base station indicated in the prediction report.
3 . The source base station of claim 2 , wherein the prediction report comprises a predicted signal change corresponding to each of the candidate base stations and the first predicted base station, and the operation of determining the non-target base station further comprises the following operations: in response to the indication message corresponding to the user device decision indication, generating a prediction confidence value corresponding to the first prediction base station based on the prediction signal change of each of the candidate base stations; and in response to the prediction confidence value being less than a threshold, determining the first predicted base station to be the non-target base station.
4 . The source base station of claim 2 , wherein the prediction report comprises a predicted signal change corresponding to each of the candidate base stations and the first predicted base station, and the operation of determining the non-target base station further comprises the following operations: receiving a base station status information from each of the candidate base stations; generating a prediction confidence value corresponding to the first prediction base station based on the prediction signal change corresponding to each of the candidate base stations and the base station status information of each of the candidate base stations; and in response to the prediction confidence value being less than a threshold, determining the first predicted base station to be the non-target base station.
5 . The source base station of claim 1 , wherein the prediction report comprises a predicted signal change corresponding to each of the candidate base stations, and the operation of determining the non-target base station further comprises the following operations: selecting a second predicted base station from the candidate base stations based on the predicted signal change corresponding to each of the candidate base stations; and setting the second predicted base station as the non-target base station.
6 . The source base station of claim 5 , wherein the processor further executes the following operations: receiving a base station status information from each of the candidate base stations; selecting the second predicted base station from the candidate base stations based on the predicted signal change corresponding to each of the candidate base stations and the base station status information of each of the candidate base stations; and setting the second predicted base station as the non-target base station.
7 . The source base station of claim 6 , wherein the base station status information comprises a load status and a current location.
8 . The source base station of claim 1 , wherein the prediction report is generated by the user device performing the following operations: measuring a trajectory information of the user device; and generating the prediction report based on a historical signal sequence value of each of the candidate base stations and the trajectory information of the user device.
9 . The source base station of claim 8 , wherein the trajectory information comprises a spatial position, a moving direction, and a moving speed of the user device.
10 . The source base station of claim 1 , wherein the processor further performs the following operations: receiving a handover success message from a target base station; and in response to receiving the handover success message from the target base station, transmitting a state transfer message to the target base station, wherein the state transfer message comprises a sequence number.
11 . The source base station of claim 1 , wherein the candidate base stations in the candidate base station list are generated by the source base station performing a conditional handover decision operation, and the processor further performs the following operations: receiving a handover request confirmation message from each of the candidate base stations; and generating the radio resource control reconfiguration message based on the handover request confirmation messages.
12 . The source base station of claim 1 , wherein the indication message comprises a decision indication, a prediction parameter indication, and an output type indication.
13 . A transmission method, being adapted for use in a source base station, wherein the source base station is communicatively connected to a user device and a plurality of candidate base stations, and the transmission method comprises the following steps: transmitting a radio resource control reconfiguration message to the user device, wherein the radio resource control reconfiguration message comprises an indication message and a candidate base station list, and the candidate base station list is configured to indicate the candidate base stations; determining a non-target base station among the candidate base stations based on a prediction report received from the user device, wherein the prediction report is generated based on the indication message; and transmitting a handover cancel request to the non-target base station among the candidate base stations to make the non-target base station release a reserved resource corresponding to the user device.
14 . The transmission method of claim 13 , wherein the indication message comprises a decision indication, and the step of determining the non-target base station further comprises the following steps: determining whether the indication message corresponds to a user device decision indication; and in response to the indication message corresponding to the user device decision indication, determining the non-target base station among the candidate base stations based on a first predicted base station indicated in the prediction report.
15 . The transmission method of claim 14 , wherein the prediction report comprises a predicted signal change corresponding to each of the candidate base stations and the first predicted base station, and the step of determining the non-target base station further comprises the following steps: in response to the indication message corresponding to the user device decision indication, generating a prediction confidence value corresponding to the first prediction base station based on the prediction signal change of each of the candidate base stations; and in response to the prediction confidence value being less than a threshold, determining the first predicted base station to be the non-target base station.
16 . The transmission method of claim 14 , wherein the prediction report comprises a predicted signal change corresponding to each of the candidate base stations and the first predicted base station, and the step of determining the non-target base station further comprises the following steps: receiving a base station status information from each of the candidate base stations; generating a prediction confidence value corresponding to the first prediction base station based on the prediction signal change corresponding to each of the candidate base stations and the base station status information of each of the candidate base stations; and in response to the prediction confidence value being less than a threshold, determining the first predicted base station to be the non-target base station.
17 . The transmission method of claim 13 , wherein the prediction report comprises a predicted signal change corresponding to each of the candidate base stations, and the step of determining the non-target base station further comprises the following steps: selecting a second predicted base station from the candidate base stations based on the predicted signal change corresponding to each of the candidate base stations; and setting the second predicted base station as the non-target base station.
18 . The transmission method of claim 17 , wherein the transmission method further comprises the following operations: receiving a base station status information from each of the candidate base stations; selecting the second predicted base station from the candidate base stations based on the predicted signal change corresponding to each of the candidate base stations and the base station status information of each of the candidate base stations; and setting the second predicted base station as the non-target base station.
19 . The transmission method of claim 13 , wherein the prediction report is generated by the user device performing the following steps: measuring a trajectory information of the user device; and generating the prediction report based on a historical signal sequence value of each of the candidate base stations and the trajectory information of the user device.
20 . The transmission method of claim 19 , wherein the trajectory information comprises a spatial position, a moving direction, and a moving speed of the user device.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Taiwan Application Serial Number 113142582, filed Nov. 6, 2024, which is herein incorporated by reference in its entirety. BACKGROUND Field of Invention The present invention relates to a source base station and transmission method. More particularly, the present invention relates to a source base station and a transmission method that can improve the efficiency of mobile communication network resource usage. Description of Related Art In the existing traditional handover (HO) operation, the operation still relies on the measurement report of the user device and the decision-making of the source base station (source gNB), and the handover is triggered when the signal strength reaches the threshold. However, this method needs to be very strict in setting the threshold. A slight error can easily lead to premature or late handover, and can easily lead to handover failure and service interruption. In the prior art, conditional handover operation has been proposed. The source base station evaluates the measurement report of the user device, requests reserved resources from potential handover candidate base stations in advance, and notifies the user device of the handover conditions of each candidate base station. The conditional handover operation can effectively reduce the probability of handover failure and improve the handover smoothness of the user device. However, according to the current handover specifications, the source base station will require multiple potential candidate base stations to reserve resources in advance to ensure continuous connection and service quality when the user device is moving. In this case, these reserved resources need to remain occupied before the user device actually switches. When the user device detects that a candidate base station meets the handover conditions, the user device will select one of the candidate base stations for handover operation. In other words, all potential candidate base stations will reserve resources and wait for the user device to perform the handover, and will only receive a resource release notification from the source base station after the user device successfully performs the handover. Under the development trend of 5G/6G network densification, user devices will frequently perform handovers; and the current handover operation specifications for the release of candidate base station reserved resources will affect the overall system performance, such as: connection capacity. Accordingly, there is an urgent need for a source base station and a transmission method that can improve the efficiency of mobile communication network resource usage. SUMMARY An objective of the present disclosure is to provide a source base station. The source base station includes a transceiver interface and a processor. The transceiver interface is communicatively connected to a user device and a plurality of candidate base stations. The processor is electrically connected to the transceiver interface. The processor transmits a radio resource control reconfiguration message to the user device, wherein the radio resource control reconfiguration message comprises an indication message and a candidate base station list, and the candidate base station list is configured to indicate the candidate base stations. The processor determines a non-target base station among the candidate base stations based on a prediction report received from the user device, wherein the prediction report is generated based on the indication message. The processor transmits a handover cancel request to the non-target base station among the candidate base stations to make the non-target base station release a reserved resource corresponding to the user device. Another objective of the present disclosure is to provide a transmission method, which is adapted for use in a source base station. The source base station is communicatively connected to a user device and a plurality of candidate base stations. The transmission method comprises the following steps: transmitting a radio resource control reconfiguration message to the user device, wherein the radio resource control reconfiguration message comprises an indication message and a candidate base station list, and the candidate base station list is configured to indicate the candidate base stations; determining a non-target base station among the candidate base stations based on a prediction report received from the user device, wherein the prediction report is generated based on the indication message; and transmitting a handover cancel request to the non-target base station among the candidate base stations to make the non-target base station release a reserved resource corresponding to the user device. According to the above descriptions, the transmission technology (including the source base station and the method) provided by the present disclosure actively transmits the