CN115529644A - A method and NR system for improving the success rate of Xn-based interface - Google Patents

Abstract

The invention provides a method for improving success rate based on an Xn interface and an NR system, wherein the method comprises the following steps: by optimally designing Xn interface signaling, a new reason enumeration is added in a Cause cell of a 38.423 protocol: the UE does not support the BWP bandwidth, and the reason for feeding back the switching failure from the target cell to the source cell when switching based on the Xn interface is that the UE does not support each BWP bandwidth of the target cell. The invention can effectively reduce the times of switching failure caused by the mismatch of the maximum bandwidth supported by the UE and the BWP bandwidth of the target cell based on the Xn interface switching, and is favorable for improving the success rate of the Xn interface switching.

Description

A method and NR system for improving the success rate of Xn-based interface

technical field

The present invention relates to the field of communication technology, in particular, to a method and NR system for improving the success rate based on an Xn interface.

Background technique

The 3GPP wireless NR system 38.331 protocol defines BWP (BandWidth Part, partial bandwidth, which is a continuous bandwidth in the cell configuration frequency band, which can be less than or equal to the cell bandwidth) configuration parameters, which are used to flexibly configure UEs working in various bandwidths BWP. Its related protocol definition is shown in Figure 1.

The BWP bandwidth that the UE can work on is restricted by the UE capability, and the BWP bandwidth cannot be greater than the bandwidth indicated by the UE capability. Parameters related to UE capabilities are defined in the 38.331 protocol, as shown in FIG. 2 .

When the UE initiates a handover based on the Xn interface, if the bandwidth of each BWP configured by the target cell is greater than the maximum bandwidth that the UE can support, the target cell cannot allocate resources for the UE, and can only reply the HANDOVERPREPARATION FAILURE message to the source cell on the Xn interface , feedback switching failed.

The HANDOVER PREPARATION FAILURE message will carry a Cause information element, which is used to indicate the reason for the handover failure. However, there is no proper reason defined in the Cause information element, which can let the source cell know that the handover failure is because the BWP bandwidth of the target cell exceeds the UE capability, and the source cell will select UE with the same or worse bandwidth capability to initiate a handover to the target cell. These UEs will fail in handover because the target cell cannot allocate resources, thereby reducing the success rate of handover based on the Xn interface.

Contents of the invention

The present invention aims to provide a method and NR system for improving the success rate based on the Xn interface, so as to solve the handover success caused by the handover failure caused by the BWP bandwidth of the target cell exceeding the maximum bandwidth supported by the UE when handover based on the Xn interface in the 3GPP wireless NR system rate drop problem.

A method for improving the success rate based on the Xn interface provided by the present invention includes:

By optimizing the design of the Xn interface signaling, a new cause enumeration is added in the Cause cell of the 38.423 protocol: UE does not support the BWP bandwidth, which is used to feed back the handover failure reason from the target cell to the source cell when the handover is based on the Xn interface. Support each BWP bandwidth of the target cell.

Further, UE does not support each BWP bandwidth of the target cell means:

The maximum bandwidth supported by the UE is smaller than the bandwidth of each BWP of the target cell.

Further, when the source cell obtains the value of the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth, it saves the maximum bandwidth of the UE that failed the handover as the handover bandwidth threshold of the target cell, and subsequently selects it for other UEs. When switching the target cell, if the maximum bandwidth supported by the UE to be switched is smaller than the switching bandwidth threshold of the switching target cell, the cell is not selected as the switching target cell.

Further, the process of using the method to switch the Xn interface includes the following steps:

S1, the source cell sends a HANDOVER REQUEST message to the target cell with the maximum cell bandwidth defined by the protocol as the handover bandwidth threshold, and initiates handover based on the Xn interface;

S2. The target cell obtains the maximum bandwidth that the UE can support in the cell from the UE capability information parameter of the HANDOVER REQUEST message, and compares it with the bandwidth of each BWP in the cell one by one. If the bandwidth of all BWPs is greater than the maximum bandwidth that the UE can support , then reply the HANDOVER PREPARATION FAILURE message to the source cell, and fill in the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth;

S3, the source cell obtains the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth, and compares the handover bandwidth threshold of the target cell with the maximum bandwidth supported by the UE where the handover fails. If the maximum bandwidth supported by the UE is less than the current handover bandwidth of the target cell threshold, update the target cell handover bandwidth threshold to the maximum bandwidth supported by the UE;

S4, if there is a UE in the source cell that initiates a handover based on the Xn interface, when selecting a handover target cell for the UE, compare the maximum bandwidth supported by the UE with the handover bandwidth threshold of the candidate cell, if the maximum bandwidth supported by the UE is smaller than the handover bandwidth threshold, the candidate cell is not selected as the handover target cell.

Further, the UE does not support the BWP bandwidth, which is expressed in the Cause information element of the 38.423 protocol as:

BWP Bandwidth Not Supported by UE.

The present invention also provides an NR system, and the NR system is used to implement the process of handover based on the Xn interface by adopting the above-mentioned method for improving the success rate of the Xn interface.

In summary, owing to adopting above-mentioned technical scheme, the beneficial effect of the present invention is:

The present invention can effectively reduce the number of handover failures based on the Xn interface handover due to the mismatch between the maximum bandwidth supported by the UE and the BWP bandwidth of the target cell, and helps to improve the success rate of handover based on the Xn interface.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be viewed The scope is limited, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

FIG. 1 is a definition diagram of BWP parameters in the 3GPP 38.331 protocol.

FIG. 2 is a definition diagram of UE supported bandwidth in the 3GPP 38.331 protocol.

FIG. 3 is a definition diagram of a newly added Cause enumeration in the 3GPP 38.423 protocol in an embodiment of the present invention.

FIG. 4 is a flow chart of performing Xn interface switching after the enumeration of newly added Causes in the embodiment of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

This embodiment proposes a method for improving the success rate of an Xn-based interface, including:

By optimizing the design of the Xn interface signaling, a new reason enumeration is added in the Cause cell of the 38.423 protocol: UE does not support BWP bandwidth (BWP Bandwidth Not Supported by UE, as shown in Figure 3), which is used for Xn-based interface During the handover, the target cell feeds back the handover failure to the source cell because the UE does not support each BWP bandwidth of the target cell. Wherein, the fact that the UE does not support the bandwidth of each BWP of the target cell means that the maximum bandwidth supported by the UE is smaller than the bandwidth of each BWP of the target cell.

Therefore, when the source cell obtains the value of the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth, it saves the maximum bandwidth of the UE that failed the handover as the handover bandwidth threshold of the target cell, and then selects it for other UEs. When switching the target cell, if the maximum bandwidth supported by the UE to be switched is smaller than the switching bandwidth threshold of the switching target cell, the cell is not selected as the switching target cell.

Through the above design, as shown in Figure 4, the process of using the method to switch the Xn interface includes the following steps:

S1, the source cell sends a HANDOVER REQUEST message to the target cell with the maximum cell bandwidth defined by the protocol as the handover bandwidth threshold, and initiates handover based on the Xn interface;

S2. The target cell obtains the maximum bandwidth that the UE can support in the cell from the UE capability information parameter of the HANDOVER REQUEST message, and compares it with the bandwidth of each BWP in the cell one by one. If the bandwidth of all BWPs is greater than the maximum bandwidth that the UE can support , then reply the HANDOVER PREPARATION FAILURE message to the source cell, the Cause information element in the HANDOVER PREPARATION FAILURE message is filled with UE does not support BWP bandwidth (BWP Bandwidth NotSupported by UE);

S3, the source cell obtains the Cause cell in the HANDOVER PREPARATION FAILURE message as UE does not support BWP bandwidth (BWP Bandwidth Not Supported by UE), and compares the handover bandwidth threshold of the target cell with the maximum bandwidth supported by the UE for handover failure. If the maximum bandwidth supported by the UE is If the bandwidth is less than the current handover bandwidth threshold of the target cell, update the handover bandwidth threshold of the target cell to the maximum bandwidth supported by the UE;

S4, if there is a UE in the source cell that initiates a handover based on the Xn interface, when selecting a handover target cell for the UE, compare the maximum bandwidth supported by the UE with the handover bandwidth threshold of the candidate cell, if the maximum bandwidth supported by the UE is smaller than the handover bandwidth threshold, the candidate cell is not selected as the handover target cell.

Example 2

This embodiment implements an NR system, and the NR system is used to perform the process of switching based on the Xn interface by using the method for improving the success rate of the Xn interface as described in Embodiment 1, specifically:

S1, the source cell sends a HANDOVER REQUEST message to the target cell with the maximum cell bandwidth defined by the protocol as the handover bandwidth threshold, and initiates handover based on the Xn interface;

S2. The target cell obtains the maximum bandwidth that the UE can support in the cell from the UE capability information parameter of the HANDOVER REQUEST message, and compares it with the bandwidth of each BWP in the cell one by one. If the bandwidth of all BWPs is greater than the maximum bandwidth that the UE can support , then reply the HANDOVER PREPARATION FAILURE message to the source cell, the Cause information element in the HANDOVER PREPARATION FAILURE message is filled with UE does not support BWP bandwidth (BWP Bandwidth NotSupported by UE);

S3, the source cell obtains the Cause cell in the HANDOVER PREPARATION FAILURE message as UE does not support BWP bandwidth (BWP Bandwidth Not Supported by UE), and compares the handover bandwidth threshold of the target cell with the maximum bandwidth supported by the UE for handover failure. If the maximum bandwidth supported by the UE is If the bandwidth is less than the current handover bandwidth threshold of the target cell, update the handover bandwidth threshold of the target cell to the maximum bandwidth supported by the UE;

S4, if there is a UE in the source cell that initiates a handover based on the Xn interface, when selecting a handover target cell for the UE, compare the maximum bandwidth supported by the UE with the handover bandwidth threshold of the candidate cell, if the maximum bandwidth supported by the UE is smaller than the handover bandwidth threshold, the candidate cell is not selected as the handover target cell.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A method for promoting success rate based on Xn interface, characterized in that, the method comprises: By optimizing the design of the Xn interface signaling, a new cause enumeration is added in the Cause cell of the 38.423 protocol: UE does not support the BWP bandwidth, which is used to feed back the handover failure reason from the target cell to the source cell when the handover is based on the Xn interface. Support each BWP bandwidth of the target cell. 2. The method for improving the success rate based on the Xn interface according to claim 1, wherein the UE does not support each BWP bandwidth of the target cell and refers to: The maximum bandwidth supported by the UE is smaller than the bandwidth of each BWP of the target cell. 3. The method for improving the success rate based on the Xn interface according to claim 2, characterized in that, when the source cell obtains the value of the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth, the failed UE will be handed over Save the maximum bandwidth of the target cell as the handover bandwidth threshold of the target cell. When selecting a handover target cell for other UEs, if the maximum bandwidth supported by the UE to be handed over is less than the handover bandwidth threshold of the handover target cell, the cell will not be selected as the handover target cell . 4. the promotion according to claim 1 is based on the method for Xn interface success rate, it is characterized in that, adopting described method to carry out the flow process of Xn interface switching comprises the steps:: S1, the source cell sends a HANDOVERREQUEST message to the target cell with the maximum cell bandwidth defined by the protocol as the handover bandwidth threshold, and initiates handover based on the Xn interface; S2. The target cell obtains the maximum bandwidth that the UE can support in the cell from the UE capability information parameter of the HANDOVER REQUEST message, and compares it with the bandwidth of each BWP in the cell one by one. If the bandwidth of all BWPs is greater than the maximum bandwidth that the UE can support , then reply the HANDOVER PREPARATION FAILURE message to the source cell, and fill in the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth; S3, the source cell obtains the Cause information element in the HANDOVER PREPARATION FAILURE message that the UE does not support the BWP bandwidth, and compares the handover bandwidth threshold of the target cell with the maximum bandwidth supported by the UE where the handover fails. If the maximum bandwidth supported by the UE is less than the current handover bandwidth of the target cell threshold, update the target cell handover bandwidth threshold to the maximum bandwidth supported by the UE; S4, if there is a UE in the source cell that initiates a handover based on the Xn interface, when selecting a handover target cell for the UE, compare the maximum bandwidth supported by the UE with the handover bandwidth threshold of the candidate cell, if the maximum bandwidth supported by the UE is smaller than the handover bandwidth threshold, the candidate cell is not selected as the handover target cell. 5. The method for improving the success rate based on the Xn interface according to claim 1, wherein the UE does not support the BWP bandwidth and is expressed in the Cause information element of the 38.423 protocol as: BWP Bandwidth Not Supported by UE. 6. An NR system, characterized in that the NR system is used to perform the process of switching based on the Xn interface by using the method for improving the success rate based on the Xn interface according to any one of claims 1-5.

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