CN107872851B - Switching method, system and base station - Google Patents
Switching method, system and base station Download PDFInfo
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- CN107872851B CN107872851B CN201610856811.0A CN201610856811A CN107872851B CN 107872851 B CN107872851 B CN 107872851B CN 201610856811 A CN201610856811 A CN 201610856811A CN 107872851 B CN107872851 B CN 107872851B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
- H04W36/0027—Control or signalling for completing the hand-off for data sessions of end-to-end connection for a plurality of data sessions of end-to-end connections, e.g. multi-call or multi-bearer end-to-end data connections
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/16—Performing reselection for specific purposes
- H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/26—Reselection being triggered by specific parameters by agreed or negotiated communication parameters
- H04W36/28—Reselection being triggered by specific parameters by agreed or negotiated communication parameters involving a plurality of connections, e.g. multi-call or multi-bearer connections
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Abstract
The invention discloses a switching method, a system and a base station, and relates to the technical field of mobile communication. The base station of the switching target side determines whether the dual-connection service can be provided or not according to the transmission delay information between the dual-connection base stations, and feeds back the dual-connection service to the base station of the switching source side, so that the base station of the switching source side determines whether the terminal performs dual-connection switching or not according to the information fed back by the base station of the switching target side, and the call drop risk of the terminal during the dual-connection switching is reduced.
Description
Technical Field
The present invention relates to the field of mobile communications technologies, and in particular, to a handover method, a handover system, and a base station.
Background
With the rise of the capacity and coverage demand of users on LTE (Long Term Evolution) networks, Small cells (Small cells) are inevitably introduced in future LTE networks to absorb traffic and enhance coverage.
In the standard research of 3GPP (3rd Generation Partnership Project) R12/13(Release 12/13, version 12/13), the Small Cell Enhancement (SCE) topic mainly studies related problems such as network capacity and mobility in heterogeneous networks. In the research subject, an architecture in which a user plane and a control plane are separated is mainly researched, as shown in fig. 1, a Small evolved Node B (SeNB) performs only user plane transmission for a terminal user, a Macro evolved Node B (MeNB) performs user plane and control plane transmission for a Macro base station (MeNB), and the Small base station and the Macro base station interact with each other through an Xn interface. The method is called Dual Connection (Dual Connection), can reduce interference to a control channel of a macro base station under the condition of same-frequency deployment, and can simultaneously and effectively utilize resources of the macro base station and a small base station to improve the throughput of a terminal, reduce the switching frequency between the base stations and improve the user experience.
In the dual connectivity enhancement research of 3GPP R13, an optimization scheme of a single (or dual) connectivity scenario is added, and the main purpose is to make a user enter a dual connectivity state more quickly, so as to achieve improvement of throughput and user experience. The application scenario is as shown in fig. 2, a User Equipment (UE) is handed over from a source base station (eNB1) to a target base station (eNB2) and a small base station (SeNB), and connects the target base station and the small base station. A part of the signaling flow is shown in fig. 3, and in step S302, the terminal reports the measurement results of the target macro base station and the small cell to the source macro base station; step S304, the source base station sends a switching request to the target macro base station according to the measurement result, wherein the switching request carries the measurement result of the small base station; step S306, the target macro base station sends a small base station adding Request (SeNB Addition Request) to the small base station after receiving the switching Request; step S308, the small base station sends a small base station Addition Response (SeNB Addition Response) to the target macro base station; step S310, the target macro base station sends a switching response to the source base station, wherein the switching response carries the configuration information of the target macro base station and the small base station. Compared with the traditional single connection-to-single connection switching, the signaling flow has the following characteristics: and adding a small base station adding process, namely sending a small base station adding request to the small base station by the target macro base station in the step S306 and sending a small base station adding response to the target macro base station by the small base station in the step S308, and realizing the information pre-configuration of the small base station by the target side in the switching preparation process. Therefore, more time delay is generated in the process of handover preparation, and as the dual connectivity is mainly applied to a non-ideal transmission backhaul system, the time for handover preparation increases by tens of milliseconds or even longer, and especially when the time delay in the process of adding the small base station is too long, the risk of call drop is likely to be brought to the terminal to be handed over, thereby reducing the user experience.
Disclosure of Invention
The invention aims to solve the technical problems that: how to reduce the call drop risk of the terminal in the dual-connection switching.
According to an aspect of the present invention, there is provided a handover method, including: a first base station receives a switching request sent by a source base station, wherein the switching request comprises information of a second base station, the second base station is positioned in the coverage range of the first base station, and a communication interface is arranged between the second base station and the first base station; the first base station determines the dual-connection switching information of the terminal according to the transmission delay information of the first base station and the second base station, wherein the dual-connection switching information of the terminal comprises whether the terminal respectively initiates access to the first base station and the second base station after receiving a switching command; the first base station sends a switching response to the source base station, wherein the switching response carries the dual-connection switching information of the terminal, so that the source base station indicates whether the terminal respectively initiates access to the first base station and the second base station after receiving the switching command according to the dual-connection switching information of the terminal.
According to a second aspect of the present invention, there is provided a base station, which is a first base station, including: a handover request receiving unit, configured to receive a handover request sent by a source base station, where the handover request includes information of a second base station, the second base station is located within a coverage area of the first base station, and a communication interface is arranged between the second base station and the first base station; a dual-connection determining unit, configured to determine dual-connection handover information of the terminal according to transmission delay information of the first base station and the second base station, where the dual-connection handover information of the terminal includes whether the terminal initiates access to the first base station and the second base station respectively after receiving a handover command; and the switching response sending unit is used for sending a switching response to the source base station, wherein the switching response carries the dual-connection switching information of the terminal, so that the source base station indicates whether the terminal respectively initiates access to the first base station and the second base station after receiving the switching command according to the dual-connection switching information of the terminal.
According to a third aspect of the present invention, there is provided a handover system comprising: a terminal, a source base station, a second base station and the base station of the foregoing embodiment, the base station being a first base station. The terminal is connected with the source base station; and the source base station is used for sending a switching request of the terminal to the first base station, wherein the switching request comprises information of the second base station, receiving a switching response sent by the first base station, and indicating whether the terminal respectively initiates access to the first base station and the second base station after receiving the switching command according to the dual-connection switching information of the terminal carried in the switching response, the second base station is positioned in the coverage range of the first base station, and a communication interface is arranged between the second base station and the first base station.
In the invention, the base station at the switching target side determines whether the dual-connection service can be provided or not according to the transmission delay information between the dual-connection base stations, and feeds back the dual-connection service to the base station at the switching source side, so that the base station at the switching source side determines whether the terminal performs dual-connection switching or not according to the information fed back by the base station at the switching target side, and the call drop risk of the terminal during dual-connection switching is reduced.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 shows a network topology diagram of a dual connectivity scenario.
Fig. 2 shows a network topology diagram of a dual connection handover scenario.
Fig. 3 shows a signaling flow diagram of a prior art dual connection handover.
Fig. 4 is a flowchart illustrating a handover method according to an embodiment of the present invention.
Fig. 5 is a flowchart illustrating a handover method according to an application example of the present invention.
Fig. 6 is a flowchart illustrating a handover method according to another embodiment of the present invention.
Fig. 7 is a flowchart illustrating a handover method according to another embodiment of the present invention.
Fig. 8 is a schematic structural diagram of a base station according to an embodiment of the present invention.
Fig. 9 is a schematic structural diagram of a switching system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The scheme is provided aiming at the problem that when a terminal is connected to dual connection by single (or dual) connection in the prior art, a target base station realizes information pre-configuration of a small base station in the switching preparation process, so that a larger time delay can be introduced, and the call drop risk of a user is increased.
The handover method of the present invention is described below with reference to fig. 4 to 7.
Fig. 4 is a flowchart of an embodiment of a handover method according to the present invention. As shown in fig. 4, the method of this embodiment includes:
step S402, the source base station sends a handover request to the first base station, and correspondingly, the first base station receives the handover request of the terminal sent by the source base station, where the handover request includes information of the second base station to be handed over.
The second base station is located within the coverage of the first base station, and a communication interface, such as an X2 interface, is provided between the second base station and the first base station. The source base station and the first base station are, for example, macro base stations, the second base station is, for example, a small base station (as shown in fig. 2) within the coverage of the target macro base station, and the source base station, the first base station, and the second base station may also be other types of base stations, which is not limited to the illustrated example. The information of the second base station is, for example, an identifier of the second base station or an identifier of a cell in the second base station, and when the information of the second base station is the identifier of the cell in the second base station, the first base station may obtain the identifier of the second base station according to a correspondence between the cell and the second base station. The identity of the cell is, for example, ECGI (E-UTRAN cell global identity).
Step S404, the first base station determines the dual-connection switching information of the terminal according to the transmission delay information of the first base station and the second base station.
The dual-connection switching information of the terminal comprises whether the terminal respectively initiates access to the first base station and the second base station after receiving the switching command. Specifically, a first base station counts bidirectional transmission delay information of the first base station and a second base station through a communication interface between the second base station and the first base station in a counting updating period, the bidirectional transmission delay information is compared with a delay threshold, when the bidirectional transmission delay information exceeds the delay threshold, it is determined that the terminal is not allowed to initiate access to the second base station after receiving a switching command, and when the bidirectional transmission delay information does not exceed the delay threshold, it is determined that the terminal respectively initiates access to the first base station and the second base station after receiving the switching command. When the transmission delay between the first base station and the second base station is too long, it indicates that the time delay of the process of pre-configuring the second base station by the first base station is long, so that the time delay of the switching process is too long, and a call drop of the terminal in the switching process is easily caused.
The bidirectional transmission delay information is, for example, an average duration of multiple bidirectional transmissions of Class1 (type 1) signaling by the first base station and the second base station in a statistic updating period. The first base station completes the statistics of the two-way transmission time delay information of the base station and the second base station, and judges whether the second base station allows the terminal to access, then checks whether the base station stores the time delay related information of the second base station, if the time delay related information of the second base station is stored, the updating is carried out, if the time delay related information of the second base station is not stored, the current statistical result is stored until the next statistical updating period begins, and the steps are repeated. When receiving a switching request sent by a source base station, the terminal can search the stored time delay related information of the second base station to determine whether to allow the terminal to initiate access to the second base station after receiving a switching command in the period, and returns to the source base station through a switching response. The second base station delay related information stored by the first base station includes, for example: the identifier of the second base station, the information of the two-way transmission delay between the base station and the second base station, and whether the terminal is allowed to initiate access to the second base station after receiving the handover command, for example, 1 indicates that the terminal is allowed to access, and 0 indicates that the terminal is not allowed to access.
Further, for example, the network manager issues a delay statistic instruction, where the delay statistic instruction includes a statistic update period and a delay threshold, and the first base station performs the step of determining whether the second base station allows the terminal to access based on the statistic update period and the delay threshold sent by the network manager. The network manager is, for example, an OMC (Operation and Maintenance Center). Further, the delay statistics signaling may further include an identifier for turning on or turning off the delay statistics function, for example, 1 indicates turning on the delay statistics function, and 0 indicates turning off the delay statistics function. The first base station counts the transmission delay information of the second base station according to the identifier for starting the delay counting function, if the delay related information of the second base station is not stored, the current counting result is stored, if the delay related information of the second base station is stored, the updating is carried out, and the first base station deletes the counting result of the second base station according to the identifier for closing the delay counting function.
Step S406, the first base station sends a switching response to the source base station, and the switching response carries the dual-connection switching information of the terminal.
The Handover response (Handover ACK) carries information of the second base station, for example, an identifier of the second base station or an identifier of a cell in the second base station.
If the terminal does not allow to initiate access to the second base station after receiving the switching command, obviously the first base station does not perform the process of pre-configuration on the second base station, but selects other second base stations with small transmission delay to perform pre-configuration or notifies the source base station not to perform dual-connection switching, thereby reducing the delay in the switching process. If the terminal allows to initiate access to the second base station after receiving the switching command, the first base station needs to pre-configure the second base station. The pre-configuration process refers to step S306 and step S308 shown in fig. 3, the first base station sends a second base station addition request to the second base station, and the second base station returns a second base station addition response to the first base station, which is not described herein again
Further, if the terminal does not allow the access to the second base station after receiving the handover command, the dual connectivity handover information of the terminal further includes a reason why the second base station does not allow the access of the terminal, where the reason includes that the transmission delay between the second base station and the first base station is too long or the configuration of the second base station is not allowed. The source base station may learn the reason, and may determine that the second base station belongs to the temporary disallowed access or the permanent disallowed access according to the reason, so as to facilitate subsequent processing, for example, if the second base station does not allow access permanently, the source base station may add the second base station to a blacklist, and then, the source base station does not control the terminal to perform the processes of measurement, handover, and the like.
Step S408, the source base station indicates whether the terminal initiates access to the first base station and the second base station respectively after receiving the switching command according to the dual-connection switching information of the terminal.
If the terminal allows initiating access to the second base station after receiving the handover command, the source base station controls the terminal to perform handover according to a handover procedure of dual connectivity in the prior art, for example, sending RRC (Radio Resource Control) Configuration or Reconfiguration (Configuration/Reconfiguration) information of the first base station and the second base station to the terminal, and the terminal initiates a Random Access (RA) according to the received RRC Configuration or Reconfiguration information, which is not described herein again.
In the method of the embodiment, the base station at the handover target side determines whether the dual connectivity service can be provided according to the transmission delay information between the dual connectivity base stations, and feeds back the determined dual connectivity service to the base station at the handover source side, so that the base station at the handover source side determines whether the terminal performs dual connectivity handover according to the information fed back by the base station at the handover target side, thereby reducing the risk of call drop of the terminal during the dual connectivity handover, and improving user experience.
In the scheme, the handover request sent by the source base station to the first base station may also carry a cell measurement result in the second base station, where the measurement result includes an identifier, a frequency point, measurement quality and/or signal strength of a cell in the second base station; and under the condition that the terminal allows to initiate access to the second base station after receiving the switching command, the first base station determines the cell in the second base station which allows to initiate access after the terminal receives the switching command according to the measurement result. Specifically, the first base station obtains the measurement result of each cell in the second base station from the handover request, and performs pre-configuration on the cell whose measurement result exceeds the threshold value, including the frequency configuration of the primary carrier and the secondary carrier, and returns the selected cell and the pre-configured information to the source base station through the handover response, when the second base station allows the terminal to access.
An application example of step S404 is described below with reference to fig. 5.
Fig. 5 is a flowchart of an application example of the handover method of the present invention. In the application example, the first base station is a macro base station (MeNB), the second base station is a small base station (SeNB), the network management is an OMC, and the macro base station performs bidirectional transmission delay information statistics on one small base station supporting dual connection in the coverage area of the macro base station. The small base station coverage area and the vicinity thereof are provided with a plurality of dual connectivity terminals, and the terminals cause frequent dual connectivity-related X2AP signaling interaction between the small base station and the macro base station due to load, service and the like in the small base station area. As shown in fig. 5, the method of this application example includes:
step S502, the OMC issues a time delay counting instruction, instructs the macro base station to start a time delay counting function, and configures related parameters.
The latency statistic instruction includes, for example:
(1) identification of the starting time delay statistical function: 1 (statistical function of time delay of opening indication)
(2) Time delay threshold value: 40ms
(3) And (3) counting an updating period: 120s
And step 504, the macro base station counts the bidirectional transmission delay information between the base station and the small base station according to the delay counting instruction.
Specifically, the macro base station receives the instruction at 00:00, the interaction time of multiple pairs of Class1 type X2 signaling (for example, a request for the macro base station to send a small base station addition request to the small base station and a response for the small base station to return the small base station addition response to the macro base station) generated between the macro base station and the small base station is monitored within a statistical update period of 120s, 4 groups of time data are monitored within the statistical update period of 120s, and each group of time data is 40ms, 60ms, 70ms and 30ms respectively. And determining the average time delay of bidirectional signaling transmission between the macro base station and the small base station to be 50ms according to the statistical result within 120 s.
Step S506, the macro base station compares the information of the two-way transmission delay between the local base station and the small base station with the delay threshold value, and determines whether the small base station allows the terminal to access.
Specifically, the average time delay of dual signaling transmission between the macro base station and the small base station is 50ms, which is greater than the time delay threshold value 40ms, so that the small base station does not allow the terminal to access the small base station while being switched to the macro base station.
Step S508, the macro base station checks whether to store the delay related information of the small base station, if so, updates, and if not, stores the currently counted delay related information of the small base station.
Specifically, when the macro base station finds that the information corresponding to the identifier of the small base station does not exist in the self time delay related information storage list at 00:02, the macro base station stores the two-way transmission time delay counted within 2 minutes into the storage list. In addition, the small cell does not allow the terminal to access, and the information in the storage list of the delay related information includes, for example:
(1) identification of the small base station;
(2) bidirectional transmission delay information: 50 ms;
(3) whether the terminal is allowed to access: and no.
In the next statistic updating period, namely between 00:02 and 00:04, the macro base station continuously monitors the interaction time of a plurality of pairs of X2 signaling of Class1 type generated between the macro base station and the small base station, the total 4 groups of statistic results in 120s are respectively 30ms, 20ms, 40ms and 30ms, the average time delay of bidirectional signaling transmission between the macro base station and the small base station is determined to be 30ms according to the statistic results in 120s, and the average time delay is smaller than the time delay threshold value 40ms, so that the small base station allows the terminal to access. When the macro base station finds that the self time delay related information storage list has the information corresponding to the identification of the small base station at 00:04, the two-way transmission time delay counted in 120s is updated into the storage list. In addition, the small cell allows the terminal to access, and the information in the storage list of the delay related information includes, for example:
(1) identification of the small base station;
(2) bidirectional transmission delay information: 30 ms;
(3) whether the terminal is allowed to access: is.
For the case that the terminal allows or disallows initiating access to the second base station after receiving the handover command, the dual connectivity handover information of the terminal in the handover response sent by the first base station to the source base station may also include different information, and the source base station further optimizes the handover process according to the information, and two embodiments of further optimizing the handover process for different cases where the second base station allows access to the terminal and disallows access to the terminal are described below with reference to fig. 6 and 7.
The first embodiment:
and under the condition that the terminal is not allowed to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal also comprises effective duration and the identification of the cell in the second base station, and the source base station controls the terminal served by the source base station not to measure the cell corresponding to the identification within the effective duration. Specifically, the source base station adds the identifier of the cell in the second base station to the blacklist when the effective duration starts, and removes the identifier of the cell in the second base station from the blacklist after the effective duration ends. As described in detail below in conjunction with fig. 6.
Fig. 6 is a flowchart of another embodiment of a handover method according to the present invention. The source base station and the first base station are taken as macro base stations, and the second base station is taken as a small base station for example to specifically describe. The terminal is switched from a source macro base station (MeNB1) to a target macro base station (MeNB2), the source macro base station initiates a switching request process, and the switching request carries the relevant information of a small base station (SeNB). In this embodiment, the target macro base station determines, according to the statistical result, that the small base station does not allow the terminal to access, and the specific steps are as follows:
step S602, the source macro base station sends a switching request to the target macro base station.
The handover request message carries an identifier of the small cell or an identifier of the small cell in the small cell, and may also carry a measurement result of the small cell in the small cell. The small cell may be plural.
Step S604, the target macro base station inquires the stored time delay related information corresponding to the small base station according to the switching request, and knows that the small base station does not allow the terminal to access.
After receiving the handover request, the target base station finds that the target base station carries the identifier of the small base station or the identifier of the small cell in the small base station or the measurement result of the small cell in the small base station, and the target base station inquires the corresponding time delay related information of the small base station in the time delay related information storage list, finds that the small base station does not allow the terminal to access, and therefore processes the handover request according to a single connection handover mode.
Step S606, the target macro base station sends a switching response to the source macro base station.
The handover response message carries the effective duration, the identity of the small cell in the small base station, information that the small base station does not allow the terminal to access, and the reason that the small base station does not allow the terminal to access, and can also carry the bidirectional transmission delay between the small base station and the target macro base station.
For example, 1 minute remains from the current time to the beginning of the next statistical update period, and the handover response message includes, for example:
(1) identification of small base station or small cell: ECGI of small cell in small base station;
(2) reason for not allowing access to the terminal: the time delay does not meet the requirement;
(3) bidirectional transmission delay between the small base station and the target macro base station: 50 ms;
(4) the effective time length is as follows: for 1 minute.
Step S608, the source macro base station controls the served terminal not to measure the small cell in the small base station within the effective duration according to the handover response.
Specifically, after receiving the handover response message, the source macro base station starts a timer according to the effective duration in the handover response, where the length of the timer is 1 minute, and the terminal is not configured with measurement of the relevant frequency of the small cell corresponding to the ECGI in the handover response within the effective duration. The information of the relevant frequency of the small cell is obtained, for example, by the frequency point information of the small base station in the neighboring cell relation of the source macro base station. For example, if the carrier frequency of the small cell corresponding to the ECGI is 1.8GHz, the source macro base station does not configure measurement of a 1.8GHz frequency point for the terminal. And when the timer with the effective duration is overtime, if the updating information of the small base station carried in the switching response message sent by the target macro base station is not received, deleting the timer corresponding to the small base station.
In the method of the embodiment, the source base station controls the terminal not to measure the cell of the second base station within the effective time period under the condition that the second base station does not allow the terminal to access, so that unnecessary loss caused by terminal measurement is reduced, and time delay is reduced.
Second embodiment:
and under the condition that the terminal allows to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal also comprises effective duration and transmission delay information of the first base station and the second base station, and is used for indicating the source base station to increase the duration of a switching timer in the dual-connection switching process of the first base station and the second base station by the transmission delay of the first base station and the second base station within the effective duration.
Fig. 7 is a flowchart illustrating a handover method according to another embodiment of the present invention. The source base station and the first base station are taken as macro base stations, and the second base station is taken as a small base station for example to specifically describe. The terminal is switched from a source macro base station (MeNB1) to a target macro base station (MeNB2), the source macro base station initiates a switching request process, and the switching request carries the relevant information of a small base station (SeNB). In this embodiment, the target macro base station determines, according to the statistical result, that the small base station allows the terminal to access, and the specific steps are as follows:
step S702, the source macro base station sends a switching request to the target macro base station,
the handover request message carries an identifier of the small cell or an identifier of the small cell in the small cell, and may also carry a measurement result of the small cell in the small cell. The small cell may be plural.
Step S704, the target macro base station queries the stored delay related information corresponding to the small base station according to the handover request, and learns that the small base station allows the terminal to access.
After receiving the handover request, the target base station finds that the target base station carries the identifier of the small base station or the identifier of the small cell in the small base station or the measurement result of the small cell in the small base station, and the target base station inquires the corresponding delay related information of the small base station in the delay related information storage list, finds that the small base station allows the terminal to access, and therefore processes the terminal according to a dual-connection handover mode.
Step S706, the target macro base station sends a small base station adding request to the small base station.
The target macro base station selects a small cell of the small base station to add according to the measurement result of the small cell in the small base station in the handover request, for example, the small cell with the measurement result exceeding a threshold value is added, and the small base station addition request carries information such as the identifier of the small cell and the frequency of a carrier wave, so that the small base station performs corresponding pre-configuration.
In step S708, the small cell returns a small cell addition response to the target macro base station.
And after the small base station is pre-configured, returning an adding result to the target macro base station.
Step S710, the target macro base station sends a handover response to the source macro base station.
The handover response message carries the effective duration, the identity of the small cell in the small base station, the information that the small base station allows the terminal to access, and the bidirectional transmission delay between the small base station and the target macro base station.
For example, 1 minute remains from the current time to the beginning of the next statistical update period, and the handover response message includes, for example:
(1) identification of small base station or small cell: ECGI of small cell in small base station;
(2) bidirectional transmission delay between the small base station and the target macro base station: 30 ms;
(3) the effective time length is as follows: 1 minute;
(4) whether the terminal is allowed to access: is.
In step S712, the source macro base station increases the time length of the handover timer in the handover process of the dual connectivity between the target macro base station and the small base station by the bidirectional transmission delay between the target macro base station and the small base station within the effective time length according to the handover response.
Specifically, after receiving the handover request response message, the source macro base station starts a timer according to the effective duration information in the handover response, and the length of the timer is 1 minute. And the source macro base station records the bidirectional transmission time delay of the target macro base station and the small base station. When another terminal residing on the source macro base station reports the signal strength of the target macro base station and the measurement result of the small cell in the small base station according to the measurement result, the source macro base station triggers the switching process of the dual connectivity to the target macro base station. Cutting machineTimer TRELOCprepIf the default value is 30ms, a switching timer T is set for the macro base station of the switching sourceRELOCprepThe time is 30ms +30ms to 60 ms. If the source macro base station receives the switching response message fed back by the target macro base station in 45ms after the source macro base station sends the switching request message, the timer T is stoppedRELOCprepTiming, if the switching response message fed back by the target macro base station is not received, the switching is failed. And when the effective duration timer is overtime, if the updating information of the small base station carried in the switching response message sent by the target macro base station is not received, deleting the timer corresponding to the small base station, deleting the recording information corresponding to the small base station, and not carrying out the optimization process of the switching timer any more.
In the method of the above embodiment, when the second base station allows the terminal to access, the source base station increases the time length of the handover timer in the handover process of the dual connectivity between the first base station and the second base station by the transmission delay between the first base station and the second base station within the effective time length. In the prior art, the time delay for the first base station to pre-configure the second base station is introduced in the dual-connection switching process, and if the original switching timer is continuously adopted, the probability of switching failure is easily increased.
In this scheme, the source base station may also periodically update the handover configuration information according to the handover response, where the handover configuration information at least includes: the identifier of the second base station, the identifier of the first base station, and the dual connectivity handover information of the terminal, in combination with the two embodiments of performing handover process optimization, the handover configuration information includes, for example:
(1) identification of the second base station: e.g., base station number of the small base station;
(2) identification of the first base station: for example, the base station number of the target macro base station to be handed over;
(3) the transmission delay information of the first base station and the second base station: for example, the bidirectional transmission delay from the small base station to the target macro base station;
(4) the effective time length is as follows: the effective duration carried in the handover response;
(5) whether the terminal is allowed to access: 1 bit of information, for example 1 indicates allowed and 0 indicates not allowed.
It should be noted that, in the foregoing embodiments, the handover request sent by the source base station to the first base station may carry information of multiple second base stations or multiple cells of multiple second base stations, and similarly, the handover response returned by the first base station to the source base station may also carry information of multiple second base stations or multiple cells of multiple second base stations. In addition, the first and second embodiments are not used to distinguish and limit the types of the base stations.
The present invention also provides a base station, which is described below with reference to fig. 8.
Fig. 8 is a block diagram of one embodiment of a base station of the present invention. The base station may be applied as a first base station, and as shown in fig. 8, the first base station 80 includes:
a handover request receiving unit 802, configured to receive a handover request sent by a source base station, where the handover request includes information of a second base station, the second base station is located in a coverage area of a first base station, and a communication interface is arranged between the second base station and the first base station.
A dual connectivity determining unit 804, configured to determine dual connectivity handover information of the terminal according to the transmission delay information of the first base station and the second base station, where the dual connectivity handover information of the terminal includes whether the terminal initiates access to the first base station and the second base station respectively after receiving the handover command.
The dual connection determining unit 804 is specifically configured to count, in a count update period, two-way transmission delay information of the first base station and the second base station through a communication interface between the second base station and the first base station, compare the two-way transmission delay information with a delay threshold, determine that the terminal is not allowed to initiate access to the second base station after receiving the handover command when the two-way transmission delay information exceeds the delay threshold, and determine that the terminal respectively initiates access to the first base station and the second base station after receiving the handover command when the two-way transmission delay information does not exceed the delay threshold. The dual connectivity determining unit 804 is configured to count an average value of time delays of multiple groups of bidirectional type 1 signaling transmitted between the first base station and the second base station in a statistics updating period, and determine the average value as bidirectional transmission time delay information.
Further, the dual connectivity determining unit 804 is configured to execute the step of determining the dual connectivity switching information of the terminal based on the statistics update period and the delay threshold sent by the network manager.
A handover response sending unit 806, configured to send a handover response to the source base station, where the handover response carries dual connectivity handover information of the terminal, so that the source base station indicates, according to the dual connectivity handover information of the terminal, whether the terminal initiates access to the first base station and the second base station after receiving the handover command, respectively.
And under the condition that the terminal is not allowed to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal also comprises effective duration and the identifier of the cell in the second base station, so that the source base station controls the terminal served by the source base station not to measure the cell corresponding to the identifier in the effective duration. Further, the dual connectivity handover information of the terminal further includes a reason that the second base station does not allow the terminal to access, where the reason includes that the transmission delay between the second base station and the first base station is too long or the configuration of the second base station is not allowed.
And under the condition that the terminal allows to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal also comprises effective duration and transmission delay information of the first base station and the second base station, and is used for indicating the source base station to increase the duration of a switching timer in the dual-connection switching process of the first base station and the second base station by the transmission delay of the first base station and the second base station within the effective duration.
Further, the handover request further includes a cell measurement result in the second base station, where the measurement result includes an identifier, a frequency point, a measurement quality, and/or a signal strength of a cell in the second base station, and the base station 80 may further include: the access information determining unit 805 is configured to determine, according to the measurement result, a cell in the second base station, where the terminal is allowed to initiate access to the second base station after receiving the handover command, when the terminal is allowed to initiate access to the second base station after receiving the handover command.
The present invention also provides a handover system, which is described below with reference to fig. 9.
Fig. 9 is a block diagram of one embodiment of a switching system of the present invention. As shown in fig. 9, the system 90 includes: a terminal 902, a source base station 904, a second base station 906 and the first base station 80 of the previous embodiment.
The terminal 902 is connected to a source base station 904.
The source base station 904 is configured to send a handover request of the terminal to the first base station 80, where the handover request includes information of the second base station 906 to be handed over, receive a handover response sent by the first base station 80, and indicate, according to dual connectivity handover information of the terminal carried in the handover response, whether the terminal 902 initiates access to the first base station 80 and the second base station 906 respectively after receiving the handover command. The second base station 906 is located within the coverage area of the first base station 80, and a communication interface is provided between the second base station 906 and the first base station 80.
Under the condition that the terminal 902 does not allow to initiate access to the second base station 906 after receiving the handover command, the dual connectivity handover information of the terminal further includes an effective duration and an identifier of a cell in the second base station 906; the source base station 904 is configured to add the identifier of the cell in the second base station 906 to the blacklist at the beginning of the valid duration, and remove the identifier of the cell in the second base station 906 from the blacklist after the valid duration is over.
The source base station 904, further configured to update the handover configuration information according to the handover response; the handover configuration information comprises at least an identity of the second base station 906, an identity of the first base station 80, and dual connectivity handover information of the terminal.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (17)
1. A method of handover, comprising:
a first base station receives a switching request sent by a source base station, wherein the switching request comprises information of a second base station, the second base station is positioned in the coverage range of the first base station, and a communication interface is arranged between the second base station and the first base station;
the first base station determines dual-connection switching information of a terminal according to the transmission delay information of the first base station and the second base station, wherein the dual-connection switching information of the terminal comprises whether the terminal respectively initiates access to the first base station and the second base station after receiving a switching command;
the first base station sends a switching response to a source base station, wherein the switching response carries dual-connection switching information of the terminal, so that the source base station indicates whether the terminal respectively initiates access to the first base station and a second base station after receiving a switching command according to the dual-connection switching information of the terminal;
under the condition that the terminal is not allowed to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal further comprises an effective duration and an identifier of a cell in the second base station, so that the source base station controls the terminal served by the source base station not to measure the cell corresponding to the identifier within the effective duration;
wherein the determining, by the first base station, the dual connectivity handover information of the terminal according to the transmission delay information of the first base station and the second base station includes:
the first base station counts and stores the two-way transmission delay information of the first base station and the second base station through a communication interface between the second base station and the first base station in a counting updating period;
the first base station inquires stored bidirectional transmission delay information corresponding to the second base station according to the switching request, the first base station compares the bidirectional transmission delay information with a delay threshold, under the condition that the bidirectional transmission delay information exceeds the delay threshold, the terminal is determined not to be allowed to initiate access to the second base station after receiving a switching command, and under the condition that the bidirectional transmission delay information does not exceed the delay threshold, the terminal is determined to respectively initiate access to the first base station and the second base station after receiving the switching command.
2. The method of claim 1,
the bidirectional transmission delay information is determined by adopting the following method:
and the first base station counts the average value of the time delay of a plurality of groups of bidirectional type 1 signaling transmitted between the first base station and the second base station in a counting updating period and determines the average value as bidirectional transmission time delay information.
3. The method of claim 1,
and the first base station executes the step of determining the dual-connection switching information of the terminal based on the statistics updating period and the time delay threshold value sent by the network manager.
4. The method of claim 1,
the controlling, by the source base station, the terminal served by the source base station not to measure the cell corresponding to the identifier within the valid duration includes:
and the source base station adds the identifier of the cell in the second base station into a blacklist when the effective duration begins, and removes the identifier of the cell in the second base station from the blacklist after the effective duration ends.
5. The method of claim 1,
and under the condition that the terminal is not allowed to initiate access to a second base station after receiving the switching command, the dual-connection switching information of the terminal also comprises the reason that the second base station is not allowed to access the terminal, wherein the reason comprises that the transmission delay between the second base station and the first base station is too long or the configuration of the second base station is not allowed.
6. The method of claim 1,
and under the condition that the terminal is allowed to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal further comprises effective duration and transmission delay information of the first base station and the second base station, and is used for indicating that a source base station increases the duration of a switching timer in the dual-connection switching process of the first base station and the second base station by the transmission delay of the first base station and the second base station within the effective duration.
7. The method of claim 1,
the handover request further includes a cell measurement result in the second base station, where the measurement result includes an identifier, a frequency point, measurement quality, and/or signal strength of a cell in the second base station;
and under the condition that the terminal allows to initiate access to a second base station after receiving the switching command, the first base station determines the cell in the second base station which the terminal allows to initiate access after receiving the switching command according to the measurement result.
8. The method of claim 1, further comprising:
the source base station updates the switching configuration information according to the switching response; the handover configuration information at least includes an identifier of the second base station, an identifier of the first base station, and dual connectivity handover information of the terminal.
9. A base station, the base station being a first base station, comprising:
a handover request receiving unit, configured to receive a handover request sent by a source base station, where the handover request includes information of a second base station, the second base station is located within a coverage area of the first base station, and a communication interface is arranged between the second base station and the first base station;
a dual-connection determining unit, configured to determine dual-connection handover information of a terminal according to transmission delay information of the first base station and the second base station, where the dual-connection handover information of the terminal includes whether the terminal initiates access to the first base station and the second base station respectively after receiving a handover command;
a handover response sending unit, configured to send a handover response to a source base station, where the handover response carries dual-connection handover information of the terminal, so that the source base station indicates, according to the dual-connection handover information of the terminal, whether the terminal initiates access to the first base station and the second base station after receiving a handover command, respectively;
under the condition that the terminal is not allowed to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal further comprises an effective duration and an identifier of a cell in the second base station, so that the source base station controls the terminal served by the source base station not to measure the cell corresponding to the identifier within the effective duration;
the dual-connection determining unit is configured to count and store two-way transmission delay information of the first base station and the second base station through a communication interface between the second base station and the first base station in a count update period, query the stored two-way transmission delay information corresponding to the second base station according to a handover request, compare the two-way transmission delay information with a delay threshold, determine that the terminal is not allowed to initiate access to the second base station after receiving a handover command when the two-way transmission delay information exceeds the delay threshold, and determine that the terminal respectively initiates access to the first base station and the second base station after receiving the handover command when the two-way transmission delay information does not exceed the delay threshold.
10. The base station of claim 9,
the dual-connection determining unit is configured to count an average value of time delays of multiple groups of bidirectional type 1 signaling transmitted between the first base station and the second base station in a count update period, and determine the average value as bidirectional transmission time delay information.
11. The base station of claim 9,
and the dual-connection determining unit is used for executing the step of determining the dual-connection switching information of the terminal based on the statistics updating period and the time delay threshold value sent by the network manager.
12. The base station of claim 9,
and under the condition that the terminal is not allowed to initiate access to a second base station after receiving the switching command, the dual-connection switching information of the terminal also comprises the reason that the second base station is not allowed to access the terminal, wherein the reason comprises that the transmission delay between the second base station and the first base station is too long or the configuration of the second base station is not allowed.
13. The base station of claim 9,
and under the condition that the terminal is allowed to initiate access to the second base station after receiving the switching command, the dual-connection switching information of the terminal further comprises effective duration and transmission delay information of the first base station and the second base station, and is used for indicating that a source base station increases the duration of a switching timer in the dual-connection switching process of the first base station and the second base station by the transmission delay of the first base station and the second base station within the effective duration.
14. The base station of claim 9,
the handover request further includes a cell measurement result in the second base station, where the measurement result includes an identifier, a frequency point, measurement quality, and/or signal strength of a cell in the second base station;
the base station further comprises:
and an access information determining unit, configured to determine, according to the measurement result, a cell in the second base station that the terminal is allowed to initiate access after receiving the handover command, when the terminal is allowed to initiate access to the second base station after receiving the handover command.
15. A handover system comprising a terminal, a source base station, a second base station and a base station according to any of claims 9 to 14, the base station being a first base station;
the terminal is connected to the source base station;
the source base station is configured to send a handover request of a terminal to the first base station, where the handover request includes information of a second base station, receive a handover response sent by the first base station, and indicate, according to dual-connection handover information of the terminal carried in the handover response, whether the terminal initiates access to the first base station and the second base station after receiving a handover command, where the second base station is located within a coverage area of the first base station, and a communication interface is arranged between the second base station and the first base station.
16. The system of claim 15,
under the condition that the terminal is not allowed to initiate access to a second base station after receiving a switching command, the dual-connection switching information of the terminal further comprises an effective duration and an identifier of a cell in the second base station;
the source base station is configured to add the identifier of the cell in the second base station to a blacklist when the effective duration starts, control the terminal served by the source base station not to measure the cell corresponding to the identifier within the effective duration, and remove the identifier of the cell in the second base station from the blacklist after the effective duration ends.
17. The system of claim 15,
the source base station is used for updating the switching configuration information according to the switching response; the handover configuration information at least includes an identifier of the second base station, an identifier of the first base station, and dual connectivity handover information of the terminal.
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| US10448289B2 (en) | 2017-05-05 | 2019-10-15 | Futurewei Technologies, Inc. | System and method for handovers in a dual connectivity communications system |
| CN112787789B (en) * | 2018-05-09 | 2022-08-16 | 中兴通讯股份有限公司 | Information acquisition method, device, equipment and computer readable storage medium |
| CN111093232B (en) * | 2018-10-23 | 2021-03-30 | 电信科学技术研究院有限公司 | Switching method, switching device and computer readable storage medium |
| CN111436073B (en) * | 2019-02-14 | 2022-07-29 | 维沃移动通信有限公司 | Determination method and device |
| CN109862595B (en) * | 2019-03-18 | 2021-07-13 | 中国联合网络通信集团有限公司 | Directional switching method and system |
| WO2020228613A1 (en) * | 2019-05-16 | 2020-11-19 | Oppo广东移动通信有限公司 | Reconfiguration message processing method, electronic device and storage medium |
| CN110536348B (en) * | 2019-05-16 | 2021-05-11 | Oppo广东移动通信有限公司 | Power consumption control method and device of terminal and storage medium |
| CN111800835B (en) * | 2019-08-14 | 2022-03-18 | 维沃移动通信有限公司 | Switching configuration method, network device, terminal device and storage medium |
| CN112188517A (en) * | 2020-09-07 | 2021-01-05 | Oppo（重庆）智能科技有限公司 | Cell residence method, device, terminal and storage medium |
| CN114302465A (en) * | 2021-12-30 | 2022-04-08 | 中国电信股份有限公司卫星通信分公司 | Rapid link recovery and switching method based on carrier aggregation |
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