TWI714647B - Mobility management for software defined radio access networks - Google Patents

Abstract

An SDN architecture, for a cellular communications system, separates the control plane and the user plane in a RAN of the cellular communication system. A controller, in the RAN, may serve a number of base stations and perform mobility management control functions (i.e., functions related to handovers), via a control plane, for base stations in the RAN. User plane traffic may be separately communicated between base stations and an SDN switch. The SDN switch, in the RAN, may be used to route data plane traffic and terminate the backhaul connection towards the core network.

Description

Mobile management for software-defined radio access networks

The invention relates to mobile management for software-defined radio access networks.

LTE (Long Term Evolution) is a standard for high-speed data wireless communication for mobile phones and data terminals (mobile devices). The LTE cellular communication system includes a radio access network (RAN) area and a "core" network area. The RAN area can handle wireless (radio) communication with mobile devices. The "core" area can handle the control functions that provide data services to mobile devices.

A trend in cellular network deployment is to use high-density access networks (sometimes called ultra-dense radio access networks (UDN)), where a large number of independent small base stations with relatively limited coverage are deployed (SC). UDN deployment can be used in outdoor or indoor traffic hotspots that require additional capacity. However, UDN deployment will cause additional challenges, such as interference between base stations. In addition, a large number of small base stations will cause a large number of sending messages from the small base stations in the network core.

100‧‧‧Environment

105‧‧‧User Equipment

110‧‧‧Radio access network

112‧‧‧Large base station

114‧‧‧Small base station

120‧‧‧Controller

125‧‧‧Software Defined Network Switch

130‧‧‧Evolved Packet Core

142‧‧‧Service Gateway

144‧‧‧Mobile management entity

146‧‧‧Packet Data Network Gateway

310‧‧‧Source Base Station

320‧‧‧Target base station

405‧‧‧Base station

410‧‧‧Base station

415‧‧‧Control base station

420‧‧‧Base station

700‧‧‧Electronic device

With the accompanying drawings, it will be easy to understand the embodiments described here from the following detailed description. To facilitate this description, similar code numbers represent similar structural elements. In the figures of the accompanying drawings, embodiments are shown by way of illustration and not limitation.

Fig. 1 is an illustrative environment diagram corresponding to a cellular network in which the system and/or method described here can be implemented; Fig. 2 is a flowchart illustrating the execution of handover within the controller in the environment of Fig. 1 Processing; Figure 3 is a signal flow chart, showing an example of handover within the controller; Figure 4 is a special environment diagram showing multiple controllers; Figure 5 is a flow chart illustrating the execution of handover between controllers in the environment of Figure 1 6 is a signal flow chart, showing an example of the signal flow diagram handed over between controllers; and FIG. 7 shows an example of electronic device components.

[Content and Implementation of the Invention]

The following detailed description refers to the accompanying drawings. The same code in different drawings can identify the same or similar elements. It should be understood that other embodiments can be used, and structural or logical changes can be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not limitative, and the scope of the embodiments is defined by the appended patent application scope and its equality.

The software-defined network of RAN used in cellular communication system is explained here. Road (SDN) architecture. The illustrated architecture separates the control plane and user plane in the RAN. For base stations in the RAN, in the RAN, the controller can serve multiple base stations and perform action management control functions (that is, functions related to handover) through the control plane. User plane traffic can communicate separately between the base station and the SDN switch. In the RAN, SDN switches can be used to arrange data plane traffic routing and terminate backhaul connections to the core network.

The separation of control and user planes can facilitate efficient action management decisions made by the controller. In addition, the separation of the control and user planes enables multiple base stations to be associated with "virtual" base stations, in which the mobile management decisions in the virtual base station are hidden from the core network (that is, communication is not required). In this way, the amount of communication with the core network can be reduced.

In one implementation, as described herein, the controller can perform the handover operation within the controller (that is, between the base stations in the virtual base station) based on the overall knowledge about the load in the virtual base station. For inter-controller handover operations (that is, between base stations in different virtual base stations), the control plane handover can be performed first between controllers of different virtual base stations. Then, the user plane handover between base stations can be performed.

FIG. 1 is a diagram of an illustrative environment 100 corresponding to a cellular network, in which the system and/or method described herein can be implemented. The environment 100 can generally provide a software-defined network (SDN) architecture in the RAN, which separates control plane signaling and user plane data traffic. In Fig. 1, the RAN control plane interface is shown in dashed lines, and the RAN user plane interface is shown in solid lines.

As shown, the environment 100 may include a mobile device called a user equipment (UE) 105, a RAN 110, and an evolved packet core (EPC) 130. The environment 100 may represent a wireless cellular communication network, such as a network based on the 3rd Generation Partnership Project (3GPP) standard. The RAN 110 can generally provide a wireless (eg, radio) interface to the UE 105. The core part can provide back-end control plane and user plane transmission path, user control and authentication, and other features.

The UE 105 may include portable computing and communication devices, such as personal digital assistants (PDAs), smart phones, mobile phones, laptop computers, tablet computers, etc. connected to a cellular wireless network. The UE 105 may also include non-portable communication devices, such as desktop computers, consumer or commercial equipment, or other devices capable of wirelessly connecting (for example, via a radio link) to a cellular wireless network. For brevity, a single UE 105 is shown. In fact, multiple UEs 105 can operate in a wireless network environment.

The RAN 110 may represent a 3GPP access network including one or more radio access technologies (RAT). The RAN 110 may include one or more base stations, such as a large base station 112 and a small base station 114. The RAN 110 may further include a controller 120 and an SDN switch 125.

In the environment of the 3GPP network, base stations such as the large base station 112 and the small base station 114 are called evolved node B (eNB). Compared with the existing eNB, the large base station 112 and the small base station 114 may contain less control logic. Instead, the control logic can be implemented by the controller 120. Compared with the small base station 114, the large base station 112 can provide The radio interface for UE 105 is for a relatively large area. The small base station 114 may be deployed to increase the system capacity and may include a coverage area within the coverage area of the large base station 112. For example, the small base station 114 may include a picocell, a femtocell, and/or its own node B. For example, the large base station 112 and the small base station 114 may implement packet data convergence protocol (PDCP) layer processing, radio link control (RLC) processing, medium access control (MAC) layer processing, and physical (PHY) Layer processing related logic.

The controller 120 may include one or more computing and communication devices as a control node for the RAN 110. Although FIG. 1 shows a single controller, in fact, multiple controllers 120 can be used to control the RAN 110, where each controller 120 can be assigned to control multiple base stations (for example, large base stations 112 and /Or small base station 114). The base station assigned to a specific controller 120 may be referred to as a "virtual base station" herein. The controller 120 is operable to perform control functions for the air interface of the RAN 110. For example, as shown in FIG. 1, as a non-limiting example, the controller 120 may perform control functions related to: (1) Radio Resource Control (RRC) signaling; (2) Radio Resource Management (RRM); (3) Self-organizing network (SON); (4) Base station (BS) control; (5) S1 application protocol (S1-AP) signaling; (6) X2-application protocol (X2-AP) signaling; And/or (7) SDN control.

As part of RRC signaling, the controller 120 can perform control functions related to the RRC protocol sublayer, which is related to the UE 105 LTE air interface with base station. The services and functions provided by the RRC sublayer can include the broadcasting of system information about the non-access stratum (NAS), the broadcasting of system information about the access stratum (AS), paging, and quality of service (QoS) management Function, and other functions. As part of RRM signaling, the controller 120 can analyze and control radio resources, such as managing co-channel interference and other wireless radio transmission characteristics. For example, the controller 120 can control the radio transmission power at the large base station 112 and the small base station 114, user allocation, bundling, data rate, modulation design used, error coding design used, etc. The relevant parameters. In some implementations, the controller 120 may also control the SON parameters at the base station and/or at the SDN switch 125. The SON parameters are generally related to the self-configuration, self-optimization, and self-recovery of the base station.

In some implementations, the controller 120 can also control the base station ("BS ctrl)", for example, the setting and operation control of the large base station 112 and the small base station 114. In some implementations, the controller 120 can also perform a function for S1 application protocol signaling between the RAN 110 and the EPC 130. The S1-AP signaling message can be routed through the SDN switch 125 to the EPC 130. For example, the S1-AP signaling message may include signaling about UE capability information, content transmission, S1 interface management, and/or other application protocol functions. In addition, the controller 120 can also perform a function for X2-AP signaling. For example, X2-AP sends messages about UE mobile management and load management. The controller 120 can also perform functions related to SDN configuration and control (SDN ctrl). For example, the controller 120 may update the SDN exchange The routing table in the machine 125 may be updated/configured with other network aspects of the SDN switch 125.

The SDN switch 125 may be an SDN device that will operate to connect the RAN 110 to the EPC 130. The SDN switch 125 can be configured by the controller 120. Although referred to as a "switch" here, the SDN switch 125 may include the functions of a router or other network devices. Generally speaking, software-defined networking refers to a computer networking method that allows network administrators to manage network services through the abstraction of higher-level functions. In SDN, the decision about whether the traffic is sent out (control plane) can be decoupled from the system that forwards traffic to the selected destination (data plane).

In one implementation, the OpenFlow protocol may be used to perform SDN-style configuration (for example, the configuration of SDN switch 125, large base station 112, and/or small base station 114). OpenFlow is a communication protocol that grants access to the forwarding plane of network switches or routers such as SDN switch 125. For example, the controller 120 can use OpenFlow messages (labeled as "OF" in FIG. 1) to communicate with the SDN switch 125 to configure packet encapsulation, decapsulation, and routing (for example, GPRS Tunneling Protocol (GTP)) User plane packet). In addition, the controller 120 can use messages (labeled as interface (OF-w) in FIG. 1) to communicate with the base station to configure the base station; to set up, modify, and/or delete wireless lines associated with the base station ; And, perform air (radio) coordination.

Figure 1 shows multiple interfaces, including OF and OF-w interfaces. The interface may refer to a physical or logical connection between devices in the environment 100. In addition to the control plane OF and OF-w interfaces, Figure 1 also shows the user plane "Xi" and "S1" interfaces. The Xi interface can be used to transmit payload data (for example, S1-U payload data) between the base station and the SDN switch 125. The S1 interface, which can include the 3GPP S1 user plane (S1-U) interface, can be used to transfer payload data between SDN switch 125 and various devices of EPC 130 (for example, SGW 142 and MME 144) .

As shown in FIG. 1, the EPC 130 may include multiple network devices, including a service gateway (SGW) 142, a mobile management entity (MME) 144, and a packet data network gateway (PGW) 146. The SGW 142 may include one or more network devices to aggregate the traffic received from one or more base stations. SGW 142 can generally handle user (data) plane traffic. The MME 144 may include one or more computing and communication devices, which perform registration operations of the UE 105 and the EPC 130, and/or perform other operations. The MME 144 can generally handle control plane traffic.

The PGW 146 may include one or more devices to serve as an interconnection point between the core network 140 and external IP networks and/or operator IP services. The PGW 146 will arrange the paths for packets to enter and exit the access network and the external IP network.

The number of devices and/or networks shown in Figure 1 is for illustrative purposes only. In fact, compared to the one shown in Figure 1, there may be additional devices and/or networks; fewer devices and/or networks; different devices and/or networks; or, differently configured devices and/or networks. Or the Internet. Alternatively, or in addition, one or more of the devices in the environment 100 may perform as described by the environment 100 One or more functions performed by another device or devices. In addition, although "direct" connections are shown in Figure 1, these connections should be interpreted as logical computing paths. In fact, there may be one or more intervening devices (for example, routers, gateways, modems, Switches, hubs, etc.).

As described above, the OF-w interface may be a control interface used by the controller 120 to control the operation of the large base station 112 and/or the small base station 140. An example implementation of OF-w messages is listed in Table I. In Table 1, the "Message Name" column contains possible names or message labels, and the "Main Field Description" column contains more detailed descriptions of the functions and/or fields of different messages.

2 is a flowchart illustrating a process 200 for performing a handover operation in the environment 100. For the process 200, the handover operation may be an in-controller handover operation. That is, the handover operation may be between base stations connected to a specific controller 120. The process 200 can be executed by the controller 120. In the following description, the term "source" base station will be used to refer to online exchanges The UE in the environment is the originating base station attached to it. The term "target" base station will be used to mean the base station to which the UE is attached at the end of the handover procedure in the network handover scenario.

The process 200 may include deciding that a handover should occur (block 210). For the process 200, assume that the handover operation is an intra-controller handover. For example, referring to FIG. 1, the handover operation may be a handover from one of the plurality of small base stations 114 to other small base stations in the plurality of small base stations 114. The handover decision can be made based on multiple factors. For example, the UE 105 may occasionally or periodically measure the strength of the signal received by the UE 105 from different base stations in the vicinity of the UE 105. The UE 105 may report the measurement to the controller 120. The controller 120 may make a decision based on the received measurement and possibly other factors such as congestion or load of other base stations in the virtual base station of the controller 120 to initiate the handover operation and cause the UE to attach to a different base station. Station (for example, to a different small base station 114). In one implementation, the controller 120 may use the trajectory or speed information related to the UE 105 to select an appropriate base station for handover.

The process 200 may also include updating the SDN switch associated with the virtual base station (block 220). For example, the update of the SDN switch 125 may include updating the routing/switching table of the SDN switch 125 to modify the registration corresponding to one or more traffic flows associated with the UE 105 so that the traffic from the target base station will continue to be forwarded To the correct entity in the EPC 130 (for example, the correct SGW 142). The OF interface can be used to perform the update of the SDN switch 125.

Process 200 may also include using the OF-w interface to update the source base station (Block 230). For example, regarding the messages marked in Table 1, the controller 120 will send a "UE Handover Command" message to the source base station. The source base station will reply to the controller 120 with a "UE status report" message.

The process 200 may further include using the OF-w interface to update the target base station (block 240). The target base station can be updated to indicate that the UE will attach to the target base station. For example, regarding the messages marked in Table 1, the controller 120 sends a "UE context setting" message to the target base station, which can provide context information for the UE to the target base station.

Since the controller 120 controls each base station in the virtual base station of the controller 120, the controller 120 knows the status of the base station in the virtual base station (for example, the traffic load status of each base station, the available radio resources, and many more). Therefore, when the in-controller handover program related to the process 200 is executed, the controller 120 can control the handover operation more effectively. As a result, the handover failure caused by the handover initiated by an inappropriate target base station (for example, a base station that is heavily loaded and does not have sufficient radio resources) is reduced.

FIG. 3 is a signal flow diagram showing an illustrative intra-controller handover involving different devices in the environment 100. In FIG. 3, the source base station and the target base station are marked as the source base station 310 and the target base station 320, respectively.

The UE 105 and the controller 120 may exchange measurement information about the connection of the UE 105 with the source base station or other base stations (at 305, "measurement"). For example, the UE 105 may transmit signal strength measurements corresponding to different base stations in the vicinity of the UE 105. According to the signal strength measurement, The controller 120 may make a handover (HO) decision regarding the UE 105 (at 310, "HO decision"). For example, when the signal strength received from the base station to which the UE is currently attached (source base station 310) falls below the threshold, the controller 120 may select another base to which the UE should be attached Station (target base station 320). The target base station 320 can be selected as another base station near the UE, where the signal strength between the UE and the target base station 320 is above a critical value, and where the target base station has available radio Resources. Since the controller 120 knows the status of all the base stations in the virtual base station of the controller 120, the controller 120 can make an optimal or near optimal handover decision. In one implementation, by transparently transmitting the RRC signal (received from the UE) to the controller through the OF-w interface (that is, through the control plane interface), measurement information can be transmitted from the base station to the controller. For example, the RRC message received by the base station can be encapsulated by the base station as an OF-w message and sent to the controller 120.

The controller 120 can then modify the SDN switch 125, for example by modifying the routing table associated with the SDN switch 125, to update the SDN switch 125 so that the SDN switch 125 will buffer the received packets for the UE 105 (at 315, "Modify Flow log in"). In one implementation, the modification may specifically include deleting the traffic flow registration related to the bearer in the SDN switch, so that the received packet related to the bearer is buffered by the SDN switch. The buffer can be executed until the handover operation is completed. For example, the OF interface can be used to modify the registration of the routing table of the SDN switch 125, so that the SDN switch 125 buffers the received It is used for UE 105 packets.

The controller 120 may then transmit the UE handover command message to the source base station 310 (at 320, "UE handover command"). The UE handover command can be transmitted via the OF-w interface and can correspond to the message "UE handover command" (Table I). The message may include, for example, the identification of the UE 105 and the indication of the RRC connection to be reconfigured. In response, the source base station 310 will initiate the RRC connection configuration for the UE 105 (at 325, "RRC Connection Reconfiguration"). The source base station 310 updates the controller 120 with a status report on the RRC reconfiguration (at 330, "UE Status Report"). The UE status report can be transmitted via the OF-w interface, and can correspond to the message "UE Status Report" (Table 1).

The controller 120 can then notify the target base station 220 of the handover. In particular, UE context information required to process handover in a way that will not cause interruption to the UE can be transmitted to the target base station 320. As shown, the controller 120 can send a UE context setting message to the target base station 320 via the OF-w interface (at 335, "UE context setting"). As detailed in Table I, the UE context setting message can include multiple information fields, including UE identification fields, security information, dedicated bearer configuration information, and random access channel (RACH) configuration information.

The RACH procedure can be executed as part of the handover operation. For example, as shown, the random access preamble can be transmitted from the UE 105 to the target base station 320 and the random access response can be transmitted from the target base station 320 to the UE 105 (at 340 and 345, "Random Access Preface" "And "Random Access Response"). During this period, the SDN switch 125 is connected The received packets for UE 105 (eg, packets from EPC 130) may be buffered in SDN switch 125 (at 350, "packet buffering"). According to the communication between the UE 105 and the target base station 320 according to the "RRC connection reconfiguration complete" message, the handover operation in the air interface can be completed (at 355). Using the OF-w interface, the target base station 320 can send the "UL RRC message transmission" message to the controller 120 (at 360), and the controller 120 can release the UE context from the source base station 310 (at 365, "UE context freed").

The controller 120 can modify the SDN switch 125 by, for example, modifying the routing table associated with the SDN switch 125 to update the SDN switch 125 so that the SDN switch 125 will appropriately forward the traffic flow received from the target base station 320 to the EPC 130, and forward the traffic flow received from the EPC 130 to the target base station 320 (at 370, "modify traffic registration"). For example, the OF interface can be used to add logins to the routing table of the SDN switch 125 to forward traffic corresponding to the UE 105 and from the target base station 320 to the EPC 130.

FIG. 4 is a diagram of the environment 100, which particularly shows a plurality of controllers 120. As previously described, each controller 120 can control multiple base stations, and a collection of base stations controlled by a specific controller 120 may be referred to as a virtual base station for the controller 120 herein. In FIG. 4, two controllers 120 are shown, labeled as controller 120-1 and controller 120-2. In addition, four base stations are displayed, labeled as base stations 405-420. The base stations 405 and 410 are shown as being connected to the controller 120-1, and the base station 420 is shown as being connected to the controller 120-2. Base station 415 can pass It is connected to both base controllers 120-1 and 120-2 by control plane messages. This base station can be regarded as being in the "Inter-controller Handover (HO) zone" which is connected to both the controllers 120-1 and 120-2 (that is, both the controller 120 can control the base station 415 ). Conversely, since the base stations 405, 410, and 420 may be controlled by only one controller, these base stations can be regarded as being in the "handover (HO) zone within the controller." It can be determined statically by the network (for example, configured by the network administrator) or dynamically determined and configured whether a specific base station is likely to be connected to multiple controllers 120 (inter-controller HO area) or be Connect to a single controller 120.

FIG. 5 is a flowchart showing a process 500 for performing a handover operation in an inter-controller handover scenario. In the following description, the term "source" will be used to mean: in the context of network handover, at the beginning of the handover operation, the UE is the starting network device (ie, base station, controller, Or SDN switch). Similarly, the term "target" will be used to mean: in the context of a network handover, when the handover operation is completed, the UE is the ending network device (ie, base station, controller, or SDN switch).

Process 500 includes determining that a handover operation should occur (block 510). For the process 500, it is assumed that the handover operation is an inter-controller handover. That is, the source base station may be associated with a different controller 120 instead of the target base station, or the source base station may be a base station in the inter-controller handover area. For example, assume that the UE 105 is attached to the base station 415 and is in contact with the controller 120-1 (source controller). Controller 120-1 can Decide (for example, based on the historical data of the UE, including trajectory, location, speed, observed neighboring base stations, etc.) that the handover is appropriate and the target base station is in contact with the controller 120-2 (target controller) The base station 420.

The source controller may send a handover request to the target controller (block 520). As mentioned, the target controller may be the controller 120-2. The request may indicate that the handover between controllers will occur. The process 500 may further include contacting the target controller (controller 120-2) with the UE as an active controller (block 530). The process 500 may further include contacting the target SDN switch (for example, SDN switch 125-2) with the UE as the active switch (block 540). The configuration performed in blocks 520-540 may all be performed in the control plane of the RAN.

The process 500 may further include sending an EPC to request a handover operation (block 550). For example, the target controller may communicate with EPC 130, such as with SGW 142 and MME 144, to request bearer modification in EPC 130 related to delivery.

After the target controller and the target SDN switch have been set (blocks 530 and 540), as described above with reference to FIGS. 2 and 3, the handover operation is equivalent to the intra-controller handover operation. The process 500 may further include executing the handover procedure in the controller (block 560). In this way, the handover between the source and target base stations can be performed.

FIG. 6 is a signal flow diagram illustrating the handover between controllers involving different devices in the environment 100 as an example. The handover procedure between controllers can be divided into two stages. The first stage involves switching the active controller 120 Related control plane operations (and, if a different SDN switch 125 is being used by the target controller, switch the SDN switch) and notify the EPC 130. As described with reference to Figures 2 and 3, the second stage follows the handover operation in the controller.

As shown in FIG. 6, using the source base station 415 and the source SDN switch 125-1, the UE 105 can initially communicate with the SGW 142 of the EPC (at 605, "Packet Data"). At some point, the source controller 120-1 can decide which handover operation should be performed (at 610, "HO decision"). As mentioned earlier, the handover decision can be based on information such as the trajectory of the UE, the location of the UE, the speed of the UE, the signal strength measurement made by the UE, and so on. The handover decision may involve the handover between base stations in different virtual base stations. For example, referring to FIG. 4, it involves the handover of base stations associated with two different controllers 120 (for example, between the source base station 415 and the target base station). Between Taiwan 420).

The source controller 120-1 may transmit the handover request to the target controller 120-2 (at 615, "Handover Request"). The handover request can be made via the control plane in the RAN 110. The handover request can be confirmed by the target controller 120-2 (at 620, "Handover Request ACK"). The source controller 120-1 may indicate to the source base station 415 that the controller and SDN switch to be used for a specific UE are being switched to the target controller 120-2 and the target SDN switch 125-2 (at 625, "Control Device and anchor switch”). The target controller 120-2 may correspondingly update the target SDN switch 125-2 to modify or increase the registration for the traffic flow corresponding to the UE (at 630, "modify the traffic registration").

The target controller 120-2 may notify the EPC 130 of the handover. As shown, the target controller 120-2 may transmit a path switch request to the MME 144 (at 635, "path switch request"). In response, MME 144 may control SGW 142 to modify the bearer path (at 640, "Modify Bearer Request"). The SGW 142 may switch the downlink (DL) path for the bearer (at 142, "switch DL path"). At this point, the packet data transmitted between the SGW 142 and the UE 105 can be transmitted through the SDN switch 152-2 and the source base station 415. The confirmation of the downlink path switch can be sent back to the target controller 120-2 (at 655 and 660, "Modify Bearer Response" and "Path Switch Response"). At this point, the target controller and the target SDN switch will be connected to the UE 105, and the handover procedure can be completed as in the handover procedure in the controller (refer to Figures 2 and 3) (at 665, " Handover procedure within the controller").

With the above-mentioned technology, a high-density radio access network can be used in a flexible manner, in which, due to handover, transmission to the core network can be reduced. In particular, it is possible that only handover between controllers requires core network signaling. However, the handover within the virtual base station of the controller can be handled in the RAN.

The term "circuit" or "processing circuit" as used herein can mean or partially mean or include application-specific integrated circuits (ASICs), electronic circuits, and processors that execute one or more software or firmware programs (Shared, dedicated, or group), and/or memory (shared, dedicated, or group), combined logic circuits, and/or other appropriate hardware components that provide the functions. In some embodiments, the circuit may be implemented or function in association with a circuit implemented by one or more software or firmware modules. In some embodiments In this case, the circuit can contain logic and can be operated at least in part by hardware.

The embodiments described herein can be implemented as a system using any suitably configured hardware and/or software. FIG. 7 shows the components of an electronic device 700 used in an example of an embodiment. In one embodiment, the electronic device 700 may be a UE, a base station, an SDN switch, a controller (for example, the controller 120), MME, PGW, or SGW. In some embodiments, the electronic device 700 may include an application circuit 702, a baseband circuit 704, a radio frequency (RF) circuit 706, a front end module (FEM) circuit 708, and one or more coupled to each other as shown at least Antenna 760. In embodiments where the electronic device 700 does not require a radio interface (for example, a data gateway, a network controller, etc.), the RF circuit 706, the FEM circuit 708, and the antenna 760 can be omitted. In other embodiments, any of these circuits may be included in different devices.

The application circuit 702 may include one or more application processors. For example, the application circuit 702 includes, but is not limited to, circuits such as one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and special-purpose processors (eg, graphics processors, application processors, etc.). The processor may be coupled to the memory/storage and/or include the memory/storage and be configured to execute instructions stored in the memory/storage so that various applications and/or operating systems can be used in the system Run on. For example, the memory/storage may include a computer-readable medium 703, which is a non-transitory computer-readable medium. In some embodiments, the application circuit 720 may be connected to or include one or more sensors, such as environmental sensors, Camera, etc.

The baseband circuit 704 may include circuits such as, but not limited to, one or more single-core or multi-core processors. The baseband circuit 704 may include one or more baseband processors and/or control logic to process the baseband signals received from the receive signal path of the RF circuit 706 and generate baseband signals for the transmit signal path of the RF circuit 706 . In order to generate and process baseband signals and control the operation of the RF circuit 706, the baseband processing circuit 704 may interface with the application circuit 702. For example, in some embodiments, the baseband circuit 704 may include a second generation (2G) baseband processor 704a, a third generation (3G) baseband processor 704b, and a fourth generation (4G) baseband processor. The processor 704c and/or other baseband processors 704d used in other current generations, developing or future generations (for example, 5th generation (5G), 7G, etc.). The baseband circuit 704 (for example, one or more baseband processors 704a-d) can handle various radio control functions that can communicate with one or more radio networks via the RF circuit 706. The radio control function may include but is not limited to signal modulation/demodulation, encoding/decoding, radio frequency offset, and so on. In some embodiments, the functions of the baseband circuit 704 may be implemented in whole or in part by a memory/storage device configured to execute instructions stored in the memory/storage. For example, the memory/storage includes a non-transitory computer readable medium 704h.

In some embodiments, the modulation/demodulation circuit of the baseband circuit 704 may include fast Fourier transform (FFT), precoding, and/or constellation mapping/demapping functions. In some embodiments, the fundamental frequency The encoding/decoding circuit with circuit 704 may include convolution, tail-biting convolution, acceleration, Viterbi, and/or low-density parity checking (LDPC) encoder/decoder functions. The embodiments of modulation/demodulation and encoder/decoder functions are not limited to these examples and may include other appropriate functions in other embodiments. In some embodiments, the baseband circuit 704 may include protocol stack components such as components of the Evolved Universal Terrestrial Radio Access Network (EUTRAN) protocol, for example, including physical (PHY) media access control (MAC) , Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and/or Radio Resource Control (RRC) components. The central processing unit (CPU) 704e of the baseband circuit 704 may be configured to run protocol stacking elements for PHY, MAC, RLC, PDCP, and/or RRC layer signaling. In some embodiments, the baseband circuit may include one or more audio digital signal processors (DSP) 704f. The audio DSP 704f may include elements for compression and decompression, echo cancellation, and in other embodiments, other suitable processing elements.

In some embodiments, the baseband circuit 704 may include protocol stack components such as components of the Evolved Universal Terrestrial Radio Access Network (EUTRAN) protocol. For example, it includes physical (PHY) media access control (MAC) ), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and/or Radio Resource Control (RRC) components. The central processing unit (CPU) 704e of the baseband circuit 704 may be configured to run protocol stacking elements for PHY, MAC, RLC, PDCP, and/or RRC layer signaling. In some embodiments, the baseband circuit may include One or more audio digital signal processors (DSP) 704f. The audio DSP 704f may include elements for compression/decompression and echo cancellation, and in other embodiments includes other suitable processing elements.

The baseband circuit 704 may further include memory/storage 704g. The memory/storage 704g can be used to load and store data and/or instructions for operations performed by the processor of the baseband circuit 704. The memory/storage 704g may specifically include non-transitory memory. The memory/storage used in one embodiment may include any combination of suitable electrical dependent memory and/or non-dependent memory. The memory/storage 704g can include different levels of memory/storage combinations, including but not limited to read-only memory (ROM) with embedded software commands (for example, firmware), random access memory ( For example, dynamic random access memory (DRAM)), cache memory, buffers, etc. The memory/storage 704g can be shared among different processors or dedicated to a specific processor.

In some embodiments, the components of the baseband circuit can be appropriately combined in a single chip, a single chip set, or configured on the same circuit board. In some embodiments, some or all of the constituent components of the baseband circuit 704 and the application circuit 702 may be implemented together on, for example, a system chip (SOC).

In some embodiments, the baseband circuit 704 can provide communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuit 704 can support the universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area network (WMAN), wireless local area network (WLAN), wireless Personal Area Network (WPAN) Communications. The embodiment in which the baseband circuit 704 is configured to support radio communications of more than one wireless protocol is called a multi-mode baseband circuit.

Using modulated electromagnetic radiation through non-solid media, the RF circuit 706 can communicate with a wireless network. In various embodiments, the RF circuit 706 may include switches, filters, amplifiers, etc., to facilitate communication with the wireless network. The RF circuit 706 may include a receiving signal path, and the receiving signal path includes a circuit to down-convert the RF signal received from the FEM circuit 708 and provide a baseband signal to the baseband circuit 704. The RF circuit 706 may also include a transmission signal path. The transmission signal path includes a circuit to up-convert the baseband signal provided by the baseband circuit 704 and provide an RF output signal to the FEM circuit 708 for transmission.

In some embodiments, the RF circuit 706 may include a receiving signal path and a transmitting signal path. The receiving signal path of the RF circuit 706 may include a mixer circuit 706a, an amplifier circuit 706b, and a filter circuit 706c. The transmission signal path of the RF circuit 706 may include a filter circuit 706c and a mixer circuit 706a. The RF circuit 706 may also include a synthesizer circuit 706d for synthesizing the frequencies used by the mixer circuit 706a of the receiving signal path and the transmitting signal path. In some embodiments, the mixer circuit 706a of the receiving signal path may be configured to down-convert the RF signal received from the FEM circuit 708 according to the synthesized frequency provided by the synthesizer circuit 706d. The amplifier circuit 706b may be configured to amplify the down-converted signal, and the filter circuit 706c may be a low-pass filter (LPF) or a band-pass filter (BPF), which is configured to remove the down-converted signal Unnecessary signals to generate output baseband signals.

The output baseband signal can be provided to the baseband circuit 704 for further processing. In some embodiments, the output baseband signal may be a zero-frequency baseband signal, but this is not necessary. In some embodiments, the mixer circuit 706a of the receiving signal path may include a passive mixer, but the scope of the embodiment is not limited thereto.

In various embodiments, when the electronic device 700 is implemented as a base station or part of a controller, the electronic device 700 may include a device for controlling the mobility of the UE. The electronic device may include a handover circuit or other logic to determine whether the UE should switch from the source (serving) base station; determine whether the source base station is in the handover area in the controller or in the handover area between controllers Within; select one or more of the target base station or target controller for the UE to be handed over; and cause the connection between the UE and the serving base station to be switched to the target base station.

In some embodiments, the mixer circuit 706a of the transmission signal path can be configured to up-convert the input baseband signal according to the synthesis frequency provided by the synthesizer circuit 706d to generate the RF output signal for the FEM circuit 708. The baseband signal can be provided by the baseband circuit 704 and can be filtered by the filter circuit 706c. The filter circuit 706c includes a low-pass filter (LPF), but the scope of the embodiment is not limited thereto.

In some embodiments, the mixer circuit 706a of the receiving signal path and the mixer circuit 706a of the transmitting signal path may include two or more mixers and may be configured for quadrature down conversion and/or up-conversion, respectively. Frequency conversion. In some embodiments, the mixer circuit 706a of the receiving signal path and the mixer circuit 706a of the transmitting signal path may include two or more mixers. The combiner can be configured for image rejection (for example, Hartley image rejection). In some embodiments, the mixer circuit 706a of the receiving signal path and the mixer circuit 706a of the transmitting signal path can be configured for direct down conversion and/or direct up conversion, respectively. In some embodiments, the mixer circuit 706a of the receiving signal path and the mixer circuit 706a of the transmitting signal path may be configured for super heterodyne operation.

In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, but the scope of the embodiments is not limited thereto. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, the RF circuit 706 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuits, and the baseband circuit 704 may include a digital baseband interface to communicate with the RF circuit 706.

In some dual-mode embodiments, separate radio IC circuits may be provided to process each spectrum signal, but the scope of the embodiment is not limited to this.

In some embodiments, the synthesizer circuit 706d may be a fractional N synthesizer or a fractional N/N+6 synthesizer. However, the scope of the embodiment is not limited to this, and other types of frequency synthesizers may be applicable. For example, the synthesizer circuit 706d can be a difference-sum synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop equipped with a frequency divider.

Based on the frequency input and divider control input, the synthesizer circuit 706d can be configured to synthesize the output frequency to be powered by the mixer of the RF circuit 706 Road 706a is used. In some embodiments, the synthesizer circuit 706d may be a fractional N/N+6 synthesizer.

In some embodiments, the frequency input can be provided by a voltage controlled oscillator (VOC), but this is not required. Depending on the desired output frequency, the divider control input can be provided by the baseband circuit 704 or the application processor 702. In some embodiments, the divider control input (eg, N) is determined from the look-up table according to the channel indicated by the application processor 702.

The synthesizer circuit 706d of the RF circuit 706 may include a divider, a delay lock loop (DLL), a multiplier, and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD), and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by N or N+6 (for example, according to the carry output) to provide a fractional division ratio. In some illustrative embodiments, the DLL includes a cascade, tunable, delay element, phase detector, charge pump, and D-type flip-flop. In these embodiments, the delay element may be configured to divide the VCO period into Nd equal phase packets, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is a VCO cycle.

In some embodiments, the synthesizer circuit 706d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (for example, two times, four times the carrier frequency) and Used in conjunction with a quadrature generator and divider circuit to generate multiple signals at carrier frequencies with multiple phases different from each other. In some embodiments, the output frequency can be LO Frequency (fLO). In some embodiments, the RF circuit 706 may include an IQ/polarity converter.

The FEM circuit 708 may include a receiving signal path, and the receiving signal path may include a circuit configured to operate on the RF signal received from one or more antennas 760, modify the received signal, and provide an amplified version of the received signal to the RF circuit 706 For further processing. The FEM circuit 708 may also include a transmission signal path, and the transmission signal path may include a circuit configured to amplify the signal for transmission provided by the RF circuit 706 for transmission by one or more of the one or more antennas 760.

In some embodiments, the FEM circuit 708 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuit may include a receiving signal path and a transmitting signal path. The receiving signal path of the FEM circuit may include a low noise amplifier (LNA) to amplify the received RF signal and provide the amplified received RF signal as an output (for example, to the RF circuit 706). The transmission signal path of the FEM circuit 708 includes a power amplifier (PA) to amplify the input RF signal (for example, provided by the RF circuit 706), and one or more filters to generate the RF signal for subsequent transmission (for example, by a Or one or more of the multiple antennas 760 transmit).

In some embodiments, the electronic device 700 may include additional components such as memory/storage, display, camera, sensor, and/or input/output (I/O) interface. In some embodiments, the electronic device of FIG. 7 may be configured to perform, for example, one or more of the methods and/or techniques described herein.

A number of examples related to the implementation of the above technology will be described below.

In the first example, the controller device of the radio access network (RAN) used in the cellular communication network may include a circuit for: receiving and user equipment (UE) from multiple base stations in the RAN Measurement information related to the connectivity strength of the base station; based on the received measurement information, decide to perform the handover operation; and, when the source base station is in contact with the second controller device in the RAN, perform the inter-controller handover operation , Wherein the circuit is also used to: determine the second controller device as the controller device with which the UE is about to communicate, and to communicate with the second controller device to switch the connection of the UE from the controller device to the first 2. Controller device.

In Example 2, the patent subject of Example 1 or any of the examples in this document may further include: wherein the circuit is used to store the connections of multiple base stations to the controller devices with which multiple base stations are connected, At least some base stations of the plurality of base stations are connected with the controller device, and other base stations of the plurality of base stations are connected with the controller device and the second controller device in the RAN; and, when the source base station is When it is in contact with the controller device and not in contact with the second controller device, execute the intra-controller handover operation, where the circuit is used to determine the target base station to which the UE will attach after the handover operation is completed, Modify the configuration of the software-defined network (SDN) switch in the RAN to indicate that the traffic with the UE should communicate with the core part of the cellular communication network through the SDN switch and the target base station.

In Example 3, the patented subject matter of Example 1 or 2 or any of the examples herein may further include: wherein, SDN is executed via a control plane interface The measurement information and configuration of the switch.

In example 4, the patent subject of example 1 or 2 or any examples in this document may further include: wherein, the circuit is used to notify the core of the cellular communication network of the handover operation during the handover operation between controllers Part, and, do not notify the core part of the cellular communication network during the handover operation in the controller.

In Example 5, the patent subject of Example 4, or any of the examples in this document, may further include: wherein the core part of the cellular network notification includes sending a path switch request to a mobile management entity (MME).

In Example 6, the patent subject of Example 1 or 2 or any of the examples herein may further include: wherein the measurement information includes the measurement information obtained by the UE and transferred from the source base station to the control device via the control plane interface.

In Example 7, the patent subject of Example 2 or any of the examples herein may further include: wherein the determination of the target base station includes determining the best target base station based on load information related to multiple base stations.

In Example 8, the patent subject of Example 2 or any of the examples in this document may further include: wherein, the configuration of the SDN switch includes deleting one or more traffic registrations to the SDN switch, so as to cause the traffic registration at the SDN switch The buffer of the associated packet.

In Example 9, the patent subject of Example 8 or any of the examples in this document may further include: wherein the modification to the SDN switch further includes adding traffic flow registration to the SDN switch to cause the traffic flow to communicate with the target base station.

In Example 10, the patent subject of Example 8 or 9 or any of the examples herein may further include: wherein the modification of the SDN switch is performed via the control plane in the RAN.

In the eleventh example, a computer-readable medium containing program instructions is used to cause one or more processors associated with a controller device of a radio access network (RAN) for a cellular communication network to use : Store the instructions of multiple base stations in the RAN to which the controller device is connected, at least some of the multiple base stations are connected to the controller device, and other base stations and controller devices in the multiple base stations Connected with the second controller device in the RAN; receiving user equipment (UE) measurement information related to the connectivity strength of the multiple base stations in the RAN and the source base station to which the UE is attached; When the source base station is in contact with another controller device in the RAN, it decides to perform a handover operation as an inter-controller handover operation based on the received measurement information. Among them, as part of the inter-controller handover performance, the The one or more processors are further used for: determining the second controller device as the controller device with which the UE is about to contact, and communicating with the second controller device to switch the connection of the UE from the controller device to the second controller device. The controller device performs the UE connection from the controller device to the second controller before performing the handover operation related to the air interface of the RAN and before performing the handover operation related to the core part of the cellular communication network Device switching.

In Example 12, the patent subject of Example 11, or any of the examples herein, may further include: wherein the program instructions cause one or more processors to: When the source base station is not connected to another controller device in the RAN contact When the handover operation is determined according to the received measurement information as an intra-controller handover operation, one or more processors are used to determine the target base station to which the UE will attach after the handover operation is completed , And modify the configuration of the software-defined network (SDN) switch in the RAN to indicate that the traffic with the UE should communicate with the core part of the cellular communication network through the SDN switch and the target base station.

In Example 13, the patented subject matter of Example 12, or any of the examples herein may further include: wherein the measurement information and configuration of the SDN switch are executed through the control plane interface.

In Example 14, the patent subject of Example 12, or any of the examples herein, may further include: wherein the program instructions cause one or more processors to: during the handover operation between controllers, notify the hive of the handover operation Do not notify the core part of the cellular communication network during the handover operation in the controller.

In Example 15, the patent subject of Example 14 or any of the examples herein may further include: wherein the core part of the notification cellular network includes sending a path switching request to a mobile management entity (MME).

In Example 16, the patent subject of Example 12, or any of the examples herein may further include: wherein the measurement information includes the measurement information obtained by the UE and transferred from the source base station to the control device via the control plane interface.

In Example 17, the patent subject of Example 12, or any of the examples herein may further include: wherein the determination of the target base station includes determining the best target base station based on load information related to multiple base stations.

In Example 18, the patent subject of Example 12, or any of the examples in this document, may further include: wherein, the modification to the SDN switch includes deleting one or more traffic flow registrations to the SDN switch, so that the SDN switch and the traffic registration The buffer of the associated packet.

In Example 19, the patent subject of Example 18, or any of the examples in this document, may further include: wherein the modification to the SDN switch further includes adding traffic flow registration to the SDN switch so that the traffic flow communicates with the target base station.

In the 20th example, the base station for the cellular communication network includes: a radio interface to connect to user equipment (UE) devices; a control plane interface to connect to the radio access for the cellular communication network The controller device of the network (RAN); the data plane interface to the software-defined network (SDN) switch in the RAN; and the processing circuit is used to: transmit the data received from the specific UE of the plurality of UE devices through the radio interface Radio Resource Control (RRC) layer measurement report decoding, the measurement report indicates the strength of connectivity of a specific UE to the base station; causes the measurement report to be provided to the controller device via the control plane interface; causes the received user plane data to pass through the data plane The interface is sent to the core part of the cellular communication network; the instructions from the controller device are processed to perform the handover between the specific UE and the second base station; and the RRC connection reconfiguration message is sent to the specific UE through the radio interface, This causes the specific UE to start communication with the second base station.

In Example 21, the patented subject matter of Example 20, or any of the examples in this document, may further include: wherein, received through the control plane interface for execution Instructions for handover operations.

In Example 22, the patent subject of Example 20, or any of the examples herein may further include: wherein the controller plane interface includes an OpenFlow interface.

In Example 23, the patent subject of Example 20 or any of the examples herein may further include: wherein the control plane interface connects the base station to a plurality of controller devices in the RAN.

In the twenty-fourth example, the base station used for the cellular communication network may include: a data plane interface mechanism for implementing the software defined network (SDN) in the radio access network (RAN) used for the cellular communication network The data plane interface of the switch; and an organization for receiving radio resource control (RRC) layer measurement reports indicating the strength of connectivity of the specific UE to the base station from a specific user equipment (UE) device via the radio interface; providing organization , Used to provide measurement reports to the controller device of the RAN used in the cellular communication network; used to receive user plane data from a specific UE via the radio interface; used to transmit the received user via the data plane interface The plane data is provided to the mechanism of the core part of the cellular communication network; the mechanism used to receive instructions from the controller device and according to the provided measurement report to execute the handover of the specific UE and the second base station; and, The RRC connection reconfiguration message is sent to the specific UE via the radio interface to cause the specific UE to start communication with the second base station in response to the mechanism for performing the handover instruction.

In Example 25, the patent subject of Example 24, or any subject in this document, is received through the control plane interface for performing handover operations Instructions given.

In Example 26, the patent subject of Example 24 or any subject in this document, wherein the control plane interface includes an OpenFlow interface.

In the foregoing description, various embodiments are described with reference to the drawings. However, it is clearly known that various modifications and changes can be made, and additional embodiments can be implemented without departing from the broader scope disclosed in the scope of the patent application described later. The description and drawings are therefore to be regarded as illustrative rather than restrictive.

For example, although the signal and/or operation series are described with reference to FIGS. 2, 3, 5, and 6, in other implementations, the order of the signals can be modified. In addition, non-dependent signals can be executed in parallel.

It can be clearly understood that many different forms of software, firmware, and hardware in the implementation shown in the figure can be used to implement the above-exemplified aspects. The real software code or specific control hardware used to implement these aspects should not be construed as limiting. Therefore, without referring to the specific software code to explain the operation and performance of the modes, it must be understood that according to the instructions in this article, software and control hardware can be designed to implement these modes.

Even if specific combinations of features are stated in the scope of the patent application and/or disclosed in the specification, these combinations are not limitative. In fact, many of these features can be combined in ways that are not specifically stated in the scope of the patent application and/or are not specifically disclosed in the specification.

Unless explicitly stated, the elements, actions, or instructions used in this application should not be construed as critical or necessary. The use of the word "and" in this article does not necessarily exclude "and/or (and/or)" sentence explanation. Similarly, the use of the word "or" in this article does not necessarily exclude the interpretation of the sentence "and/or" in that case. Moreover, as used herein, the article "a" is intended to contain one or more, and can be used interchangeably with the word "one or more". Among them, when only one item is meant, "one", "single", "only" or similar language will be used.

100‧‧‧Environment

105‧‧‧User Equipment

110‧‧‧Radio access network

112‧‧‧Large base station

114‧‧‧Small base station

120‧‧‧Controller

125‧‧‧Software Defined Network Switch

130‧‧‧Evolved Packet Core

142‧‧‧Service Gateway

144‧‧‧Mobile management entity

146‧‧‧Packet Data Network Gateway

Claims (23)

A controller device used in a radio access network (RAN) of a cellular communication network. The controller device includes a circuit for: receiving and user equipment (UE) a source from a plurality of base stations in the RAN Measurement information related to the strength of the base station’s connectivity; based on the received measurement information, a decision is made to perform a handover operation; and when the source base station is in contact with a second controller device in the RAN, execute the A first handover operation between the controller device and the second controller device, wherein the circuit is further used to: determine the second controller device as the controller device with which the UE is about to contact, and to communicate with the The second controller device communicates to switch the connection of the UE from the controller device to the second controller device. For example, the controller device of the first item of the scope of patent application, wherein the circuit is further used to: store the multiple connections of the plurality of base stations to the multiple controller devices to which the plurality of base stations are connected, the plurality of At least some of the base stations are in contact with the controller device and other base stations in the plurality of base stations are in contact with the controller device and the second controller device in the RAN; and when the source base station When connected with the controller device and not connected with the second controller device, a second handover operation is performed, wherein the circuit is further used for: Determine a target base station that the UE will attach to after the second handover operation is completed, and modify the configuration of a software-defined network (SDN) switch in the RAN to indicate that the traffic with the UE should pass through The SDN switch and the target base station communicate with a core part of the cellular communication network. For example, the controller device of the first patent application, wherein the measurement information and the configuration of the SDN switch are executed through multiple control plane interfaces. For example, in the controller device of claim 1, wherein the circuit is further used for: during the first handover operation, notify a core part of the cellular communication network of the first handover operation, and in the Do not notify the core part of the cellular communication network during the second handover operation. For example, in the controller device of the fourth patent application, informing the core part of the cellular network includes sending a path switch request to a mobile management entity (MME). For example, the controller device of the first patent application, wherein the measurement information includes the measurement information obtained by the UE and transferred from the source base station to the control device via a control plane interface. For example, in the controller device of the second patent application, the determination of the target base station includes determining an optimal target base station based on load information related to the plurality of base stations. For example, the controller device of item 2 of the scope of patent application, wherein the configuration of the SDN switch includes deleting one or more traffic flow registrations of the SDN switch to cause Buffering of packets associated with the traffic registrations at the SDN switch. For example, in the controller device of item 8 of the scope of patent application, the modification of the SDN switch includes adding traffic flow registration to the SDN switch so that the traffic flow communicates with the target base station. For example, in the controller device of the ninth patent application, the modification of the SDN switch is performed via a control plane in the RAN. A computer readable medium containing a plurality of program instructions for causing one or more processors associated with a controller device of a radio access network (RAN) for a cellular communication network to: Receive measurement information related to the strength of connectivity of a user equipment (UE) to a plurality of base stations in the RAN and a source base station to which the UE is attached; when the source base station and the RAN When the other controller device is in contact, it decides to perform a first handover operation based on the received measurement information, wherein the one or more processors are further used : Determine a second controller device as the controller device with which the UE is about to contact, and communicate with the second controller device to switch the connection of the UE from the controller device to the second controller device Before performing a plurality of handover operations related to the air interface of the RAN and before performing a plurality of handover operations related to a core part of the cellular communication network, execute from the controller device to the second The switching of the connection of the UE of the controller device. For example, the computer-readable medium of item 11 of the scope of the patent application, wherein the program instructions further cause the one or more processors to: When the source base station is not connected with another controller device in the RAN , Deciding to perform a second handover operation based on the received measurement information, wherein the one or more processors are further used to: determine a target base to which the UE is to be attached after the second handover operation is completed Station, and modify the configuration of a software-defined network (SDN) switch in the RAN to indicate that the traffic with the UE should pass through the SDN switch and the target base station to the core part of the cellular communication network Phase communication. For example, the computer-readable medium of item 12 of the scope of patent application, in which the measurement information and the configuration of the SDN switch are executed through multiple control plane interfaces. For example, the computer-readable medium of claim 12, wherein the program instructions further cause the one or more processors to: during the first handover operation, notify the honeycomb type of the first handover operation A core part of the communication network, and do not notify the core part of the cellular communication network during the second handover operation. For example, the computer-readable medium of item 14 of the scope of patent application, in which notifying the core part of the cellular network includes sending a path switching request to a mobile management entity (MME). For example, in the computer-readable medium of the 12th patent application, the measurement information includes the measurement information obtained by the UE and transferred from the source base station to the control device via a control plane interface. For example, the computer-readable medium of item 12 of the scope of the patent application, wherein the determination of the target base station includes determining an optimal target base station based on load information related to the plurality of base stations. For example, the computer-readable media of item 12 of the scope of patent application, where the modification to the SDN switch includes deleting one or more traffic registrations of the SDN switch so as to be associated with the traffic registrations at the SDN switch The buffer of the packet. For example, the computer-readable media of item 18 of the scope of the patent application, where the modification of the SDN switch includes the addition of traffic flow registration to the SDN switch so that the traffic flow communicates with the target base station. A base station for a cellular communication network. The base station includes: a radio interface for connecting to a plurality of user equipment (UE) devices; a control plane interface for connecting to the cellular communication network A controller device of a radio storage network (RAN); a data plane interface to a software-defined network (SDN) switch in the RAN; and a processing circuit for: A radio resource control (RRC) layer measurement report received by a specific UE in the UE device is decoded, and the measurement report indicates the strength of a connectivity of the specific UE to the base station; causing the measurement report to pass through the control plane Interface is provided to the controller device; causing the received user plane data to pass through the data plane interface Send to a core part of the cellular communication network; process an instruction from the controller device to perform a handover between the specific UE and a second base station; and generate an RRC connection reconfiguration for the specific UE Configure the message to cause the specific UE to start communication with the second base station. For example, the base station of item 20 of the scope of the patent application receives the instruction for performing the handover operation through the control plane interface. For example, in the base station of the 20th patent application, the controller plane interface includes an OpenFlow-based interface. For example, the base station of the 20th patent application, wherein the control plane interface connects the base station to a plurality of controller devices in the RAN.

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