CN104219719A - Method and system for base station handover - Google Patents

Abstract

A base station handover method and system, wherein the method includes: handover of user equipment from a source base station to a target base station; judging at the packet data convergence protocol layer of the target base station whether the signaling radio bearer of the user equipment has received the first uplink message, If yes, it is determined that the user equipment successfully accesses the target base station; the target base station transmits uplink and downlink data with the user equipment. This solution adopts the method of judging whether the UE accesses by switching the first uplink message received by the UE's SRB uplink at the PDCP entity layer, and can judge whether the UE has successfully accessed in a timely manner. At the same time, since the judgment is implemented in the PDCP, the signaling interaction between the PDCP and the RRC is reduced. Therefore, the timeliness of the data sent by the TeNB to the UE during handover can be improved, the handover delay can be reduced, and user experience can be improved.

Description

Base station switching method and system

technical field

The present invention relates to the technical field of mobile communication, in particular to a base station switching method and system.

Background technique

The overall development trend of the mobile Internet will be the mutual integration with the Internet. At the business level, the content and application experience of the mobile Internet and the traditional Internet tend to be consistent. However, the launch of mobile network products is faster than that of the traditional Internet. At the network service level, Compared with the fixed Internet, cheap and relatively fast Internet access mode has also begun to be provided.

For example, LTE (Long Term Evolution) is a wireless communication standard specially designed for mobile high-bandwidth applications. Higher bandwidth, larger capacity, and higher The effect of data transfer rate and lower transmission delay.

LTE uses a fast hard handover method to realize handover between different frequency bands and systems, so as to better realize geographical coverage and seamless handover, and to achieve compatibility with existing 3GPP and non-3GPP. Soft handover is not adopted due to the high complexity of the equipment and the difficulty in timing, which will bring the demand for higher processing capabilities. Corresponding changes have also taken place in the design of the core network, adding system architecture evolution and 3GPP modules, and realizing the compatibility of the LTE system with 3GPP and non-3GPP system switching.

In an actual communication system, when a handover occurs, a user equipment (User Equipment, UE) is handed over from a source base station (Source eNB, SeNB) to a target base station (Target eNB, TeNB). It is necessary to exchange signaling between the packet data convergence protocol layer (Packet Data Convergence Protocol, PDCP) and the radio resource control protocol layer (Radio Resource Control, RRC layer), and RRC will analyze and judge whether the access is successful, and then tell the PDCP layer, PDCP The layer then transmits uplink and downlink data. Due to the signaling interaction between PDCP and RRC, as well as the complexity of the communication mechanism and the uncertainty of the communication link, it is impossible to judge whether the UE has connected to the TeNB in time, so that the downlink data cannot be sent to the UE in time, which increases the handover delay. affect the user experience. Therefore, a reliable method for judging whether the UE is connected will be crucial to reducing the handover delay and even the service quality of the entire communication system.

Contents of the invention

Based on this, it is necessary to provide a base station handover method and system for the problem that the target base station cannot detect whether the UE is connected in time during the handover.

A base station switching method, comprising:

The user equipment is handed over from the source base station to the target base station;

Judging at the packet data convergence protocol layer of the target base station whether the signaling radio bearer of the user equipment has received the first uplink message, and if so, determining that the user equipment successfully accesses the target base station;

The target base station transmits uplink and downlink data with the user equipment.

A base station switching system, comprising:

A handover module, configured to perform the handover operation of the user equipment from the source base station to the target base station;

A judging module, configured to judge at the packet data convergence protocol layer of the target base station whether the signaling radio bearer of the user equipment has received the first uplink message, and if so, determine that the user equipment successfully accesses the target base station;

A transmission module, configured to perform an operation of transmitting uplink and downlink data between the target base station and the user equipment.

The above base station handover method and system, when the user equipment is handed over from the source base station to the target base station, judge whether the signaling radio bearer of the user equipment has received the first uplink message at the packet data convergence protocol layer of the target base station, thereby realizing Judging whether the user equipment accesses the target base station. By switching the UE's signaling radio bearer uplink at the PDCP entity layer to determine whether the UE has accessed the first uplink message received uplink, it is possible to timely determine whether the UE has successfully accessed. At the same time, since the judgment is implemented in the PDCP, the signaling interaction between the PDCP and the RRC is reduced. Therefore, the timeliness of the data sent by the TeNB to the UE during handover can be improved, the handover delay can be reduced, and user experience can be improved.

Description of drawings

Fig. 1 is an application environment diagram of a base station handover method in an embodiment;

FIG. 2 is a schematic flowchart of Embodiment 1 of the base station handover method of the present invention;

FIG. 3 is a schematic flowchart of Embodiment 2 of the base station handover method of the present invention;

FIG. 4 is a schematic structural diagram of an embodiment of a base station handover system according to the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

The base station switching method provided by the embodiment of the present invention can be applied to the system shown in Figure 1, please refer to Figure 1, Figure 1a is a schematic diagram of connection before switching, UE110 is connected to SeNB120, and SeNB120 is connected to TeNB130. Fig. 1b is a schematic diagram of connection after handover, UE110 is connected to TeNB130, and SeNB120 is connected to TeNB130. UE 110 may be a device such as, but not limited to, a smart phone, a tablet computer, a personal digital assistant, and the like.

In addition, the Chinese and English comparisons of the following examples are as follows:

Signaling Radio Bearers (SRB). The signaling radio bearer numbered 1 can be represented by SRB1 (Signalling Radio Bearer one). The sequence number (Sequence Number, SN) of the packet data unit. Packet Data Unit (PDU). Data Radio Bearers (DRB). Radio Link Control protocol layer (Radio Link Control, RLC). Acknowledged Mode (AM).

As shown in FIG. 2, it is a schematic flow diagram of Embodiment 1 of the base station handover method of the present invention, including:

Step S201: UE handover from SeNB to TeNB;

Step S202: The PDCP of the TeNB judges whether the SRB of the UE has received the first uplink message, if yes, it is determined that the UE successfully accesses the TeNB; otherwise, it continues to wait for the UE to access.

Step S203: the TeNB transmits uplink and downlink data with the UE.

This embodiment can be used for handover between LTE micro base stations. Step S202 is a judging step of judging whether the UE access is successful. When the UE is handed over from the SeNB to the TeNB, it is judged whether the SRB of the UE has received the first uplink message through the PDCP of the TeNB, so as to realize the judgment of whether the UE accesses the TeNB. By switching the first uplink message received by the UE's SRB uplink at the PDCP entity layer to determine whether the UE has accessed, it is possible to timely determine whether the UE has successfully accessed. At the same time, since the judgment is implemented in PDCP, signaling interaction between PDCP and RRC is avoided, and there is no need to send signaling at the PDCP layer to the RRC layer for judgment and return to the PDCP layer. Therefore, the timeliness of the data sent by the TeNB to the UE during handover can be improved, the handover delay can be reduced, and user experience can be improved.

In one of the embodiments, the step of determining whether the SRB of the UE receives the first uplink message by the PDCP of the TeNB includes:

The TeNB acquires the SRB label of the UE and the SN of the SRB uplink PDCP;

The TeNB judges whether the label of the SRB is 1, and whether the SN of the uplink PDCP of the SRB is 0.

This embodiment further defines how to judge whether the first uplink message is received. Obtain the SRB label of the UE and the SN of the SRB uplink PDCP to determine the SRB type of the currently switched UE and the SN of the SRB uplink PDCP PDU. When the SRB type is SRB1 and the SN of the PDCP PDU received by SRB1 uplink is 0, since It carries information related to UE and RRC access. PDCP SN is 0, indicating that this is the first uplink message sent by the UE, which indicates that the UE has already accessed. The access of the UE at this time may be the access after the reconfiguration is completed, or the access after the re-establishment is completed. Otherwise, if the type of SRB is not SRB1, continue to wait until the type of SRB is SRB1 and the SN of the PDCP PDU received uplink by SRB1 is 0.

Since this embodiment adopts the method of currently switching the SRB type of the UE and the SN of the SRB uplink PDCP PUD to detect whether the UE is connected, the problem of being unable to determine whether the UE has connected to the TeNB due to switching is solved. At the same time, the signaling interaction between PDCP and RRC is reduced. Therefore, the delay is effectively reduced and the user experience is improved.

In one of the embodiments, before the step of transmitting uplink and downlink data between the TeNB and the UE, further includes:

The TeNB detects the RLC mode of the UE DRB;

When the RLC mode is AM, it is detected whether the PDCP has received the serial number status information of the PDCP configured by the RRC layer, and if so, the TeNB transmits uplink and downlink data to the UE according to the serial number status information.

In this embodiment, the mode of the RLC that currently switches the UE DRB is judged, and whether it is the AM mode is judged. If it is in the AM mode, it is detected whether the PDCP has received the serial number status information of the PDCP configured by the RRC layer. Generally, the serial number status information will be configured before the UE accesses, and the serial number status information can be obtained directly, and then the TeNB transmits uplink and downlink data to the UE according to the serial number status information. If the serial number status information is not obtained, the PDCP needs to wait until the status report configured by the RRC layer is received before the uplink and downlink data can be sent to the UE. It is possible to distinguish which data has been sent by the SeNB according to the status report, so as to determine which data needs to be sent.

In one of the embodiments, before the step of transmitting uplink and downlink data between the TeNB and the UE, further includes:

The TeNB detects the RLC mode of the UE data radio bearer;

When the RLC mode is an unacknowledged mode, the TeNB transmits uplink and downlink data to the UE.

In this embodiment, the RLC mode of the data radio bearer is judged to determine whether it is the AM mode. If it is not in the AM mode, the uplink and downlink data can be sent to the UE immediately.

Further, the UE handover step from SeNB to TeNB includes:

SeNB sends a handover request to TeNB;

The TeNB receives the handover request sent by the SeNB, establishes a signaling radio bearer link, and sends a request confirmation instruction to the SeNB, wherein the request confirmation instruction includes configuration information for establishing a signaling radio bearer link;

The SeNB sends the request confirmation instruction to the UE;

The UE establishes a signaling radio bearer link according to the request confirmation instruction.

The various technical features in the above embodiments can be combined arbitrarily, as long as there is no conflict or contradiction between the combinations of features, but due to space limitations, they are not described one by one, so the various technical features in the above embodiments can be combined arbitrarily It also belongs to the scope disclosed in this specification.

The present invention is described by taking one of the combinations, as shown in FIG. 3 , which is a schematic flowchart of Embodiment 2 of the base station handover method of the present invention.

Step S301: When the UE switches from SeNB to TeNB, detect the SRB type of the currently switched UE and the SN of the PDCP PDU received by the SRB uplink;

Step S302: According to the detection result of step S301, whether the SRB type is SRB1, and whether the SN of the SRB1 uplink PDCP PDU is 0;

Step S303: If the SRB type of the currently switched UE is SRB1, and the SN of the uplink PDCP PDU of SRB1 is 0, since SRB1 carries information about the UE and RRC access, the PDCP SN of 0 indicates that this is the first message sent by the UE. Uplink message, which indicates that the UE has accessed. The access of the UE at this time may be the access after the reconfiguration is completed, or the access after the re-establishment is completed. Otherwise, continue to wait until the type of SRB is SRB1 and the SN of the PDCP PDU received by SRB1 uplink is 0;

Step S304: After determining that the UE has accessed the TeNB, the TeNB detects and determines whether the RLC mode of the DRB of the currently switched UE is the AM mode;

Step S305: If it is detected that the RLC mode is the AM mode, the SN needs to be configured due to the message of the AM mode. Therefore, after PDCP receives the PDCP SN status configured by the RRC layer, TeNB can send uplink and downlink data to UE according to the sequence number status information;

Step S306: If it is detected that the RLC mode is not the AM mode, the TeNB can start sending uplink and downlink data immediately.

Due to handover, it is easy to cause TeNB to be unable to know whether the UE is connected, and the solution of the present invention adopts the method of judging whether the UE is connected to the TeNB according to the SRB type of the currently handed over UE and the SN of the PDCP PDU received uplink by the SRB, which reduces the handover process Therefore, it effectively suppresses the high delay of data transmission and data interruption during the handover process, and improves the service quality of users.

According to the above base station switching method, the present invention also provides a base station switching system, as shown in FIG. 4 , which is a schematic structural diagram of an embodiment of the base station switching system of the present invention, including:

A handover module 410, configured to perform an operation of UE handover from SeNB to TeNB;

The judging module 420 is used to judge whether the SRB of the UE has received the first uplink message in the PDCP of the TeNB, and if so, judge that the UE successfully accesses the TeNB;

The transmission module 430 is configured to perform the operation of transmitting uplink and downlink data between the TeNB and the UE.

In one of the embodiments, the judging module includes:

An acquisition module, configured to perform an operation in which the TeNB acquires the SRB label of the UE and the SN of the SRB uplink PDCP;

The sub-judgment module is used to execute the operation of the TeNB judging whether the label of the SRB is 1, and whether the SN of the SRB uplink PDCP is 0.

In one of the embodiments, the transmission module is used for:

If the UE successfully accesses the TeNB, the TeNB detects the RLC mode of the UE data radio bearer; when the RLC mode is the confirmation mode, detects whether the PDCP has received the serial number status information of the PDCP configured by the RRC layer, and if so, then The TeNB transmits uplink and downlink data to the UE according to the sequence number status information.

In one of the embodiments, the transmission module is used for:

If the UE successfully accesses the TeNB, the TeNB detects the RLC mode of the UE data radio bearer; when the RLC mode is an unacknowledged mode, the TeNB transmits uplink and downlink data to the UE.

In one of the embodiments, the switching module is further configured to perform the following operations:

SeNB sends a handover request to TeNB;

The TeNB receives the handover request sent by the SeNB, establishes a signaling radio bearer link, and sends a request confirmation instruction to the SeNB, wherein the request confirmation instruction includes configuration information for establishing a signaling radio bearer link;

The SeNB sends the request confirmation instruction to the UE;

The UE establishes a signaling radio bearer link according to the request confirmation instruction

The base station switching system of the present invention corresponds to the base station switching method of the present invention one by one. The relevant technical features and technical effects in the above base station switching method embodiment are applicable to the base station switching system embodiment, and are not repeated here.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. A base station switching method, characterized in that, comprising: The user equipment is handed over from the source base station to the target base station; Judging at the packet data convergence protocol layer of the target base station whether the signaling radio bearer of the user equipment has received the first uplink message, and if so, determining that the user equipment successfully accesses the target base station; The target base station transmits uplink and downlink data with the user equipment. 2. The base station handover method according to claim 1, wherein the step of determining whether the signaling radio bearer of the user equipment receives the first uplink message at the packet data convergence protocol layer of the target base station comprises: The target base station obtains the label of the signaling radio bearer of the user equipment and the sequence number of the packet data unit of the signaling radio bearer uplink packet data convergence protocol layer; The target base station judges whether the label of the signaling radio bearer is 1, and whether the sequence number of the packet data unit of the uplink packet data convergence protocol layer of the signaling radio bearer is 0. 3. The base station handover method according to claim 1, characterized in that, before the step of transmitting uplink and downlink data between the target base station and the user equipment, further comprising: The target base station detects the radio link control protocol layer mode of the user equipment data radio bearer; When the radio link control protocol layer mode is the confirmation mode, detect whether the packet data convergence protocol layer has received the sequence number status information of the packet data convergence protocol layer configured by the radio resource control protocol layer, and if so, the target base station according to the The serial number state information transmits uplink and downlink data to the user equipment. 4. The base station handover method according to claim 1, characterized in that, before the step of transmitting uplink and downlink data between the target base station and the user equipment, further comprising: The target base station detects the radio link control protocol layer mode of the user equipment data radio bearer; When the radio link control protocol layer mode is an unacknowledged mode, the target base station transmits uplink and downlink data to the user equipment. 5. The base station handover method according to any one of claims 1 to 4, wherein the step of handing over the user equipment from the source base station to the target base station includes: The source base station sends a handover request to the target base station; The target base station receives the handover request sent by the source base station, establishes a signaling radio bearer link, and sends a request confirmation instruction to the source base station, wherein the request confirmation instruction includes configuration information for establishing a signaling radio bearer link; The source base station sends the request confirmation instruction to the user equipment; The user equipment establishes a signaling radio bearer link according to the request confirmation instruction. 6. A base station switching system, characterized in that, comprising: A handover module, configured to perform the handover operation of the user equipment from the source base station to the target base station; A judging module, configured to judge at the packet data convergence protocol layer of the target base station whether the signaling radio bearer of the user equipment has received the first uplink message, and if so, determine that the user equipment successfully accesses the target base station; A transmission module, configured to perform an operation of transmitting uplink and downlink data between the target base station and the user equipment. 7. The base station switching system according to claim 6, wherein the judging module comprises: An acquisition module, configured to perform an operation in which the target base station acquires the label of the signaling radio bearer of the user equipment and the sequence number of the packet data unit of the signaling radio bearer uplink packet data convergence protocol layer; The sub-judgment module is used to execute the operation of the target base station judging whether the label of the signaling radio bearer is 1, and whether the sequence number of the packet data unit of the uplink packet data convergence protocol layer of the signaling radio bearer is 0. 8. The base station switching system according to claim 6, wherein the transmission module is used for: If the user equipment successfully accesses the target base station, the target base station detects the radio link control protocol layer mode of the user equipment data wireless bearer; when the radio link control protocol layer mode is the confirmation mode, detects the packet data convergence protocol Whether the layer receives the sequence number status information of the packet data convergence protocol layer configured by the radio resource control protocol layer, and if so, the target base station transmits uplink and downlink data to the user equipment according to the sequence number status information. 9. The base station switching system according to claim 6, wherein the transmission module is used for: If the user equipment successfully accesses the target base station, the target base station detects the radio link control protocol layer mode of the user equipment data radio bearer; when the radio link control protocol layer mode is an unacknowledged mode, the target base station transmit uplink and downlink data to the user equipment. 10. The base station switching system according to any one of claims 6 to 9, wherein the switching module is further configured to perform the following operations: The source base station sends a handover request to the target base station; The target base station receives the handover request sent by the source base station, establishes a signaling radio bearer link, and sends a request confirmation instruction to the source base station, wherein the request confirmation instruction includes configuration information for establishing a signaling radio bearer link; The source base station sends the request confirmation instruction to the user equipment; The user equipment establishes a signaling radio bearer link according to the request confirmation instruction.