CN101390430A - Private base station neighbor cell reselection for closed subscriber group - Google Patents

Abstract

The present invention discloses an improved method for UE reselection of a dedicated cell. According to the present invention, the UE is in idle mode in a public network, which includes at least one public base station covering a public cell. The UE can also communicate with a dedicated network, which includes at least one dedicated base station covering a dedicated cell, to which the UE has limited access rights. When the UE approaches a cell to which it has access rights, it only performs a dedicated cell reselection search, where proximity is detected based on information about the UE and its relationship to the dedicated base station.

Description

Adjacent cell reselection for private base stations in closed user groups

technical field

The invention relates to a method of a network node and a user equipment (UE) for UE-specific cell reselection in idle mode in a public network. The public network includes at least one public base station covering the public cell, and the UE can also communicate with the private network. The private network includes at least one private base station covering the private cell, and the access rights of the UE in the private network are limited.

The invention also relates to a UE, a network node and a system for performing a reselection operation of a private cell by a UE in idle mode in a public network. The public network includes at least one public base station covering a public cell. The UE can also communicate with a private network, and the private network includes at least one private base station covering a private cell, and the access right of the UE in the private network is limited.

The invention also relates to a computer program for carrying out the method of the invention, and a computer program product for carrying out the method of the invention.

Background technique

The present invention relates to a wireless communication system, in particular a wireless communication system comprising a private base station, such as a small home appliance with access restrictions to a small group of UEs.

With the evolution of the Universal Terrestrial Radio Access Network (Enhanced UTRAN, E-UTRAN) in the 3rd Generation Partnership Program (3rd Generation Partnership Program, 3GPP) in wireless communication standards, also known as the development of Long Term Evolution (LTE) , a need for dedicated small household devices arose.

The private base station should at least include the function of the wireless base station, especially the private base station should provide the function of the wireless base station for a very small cell, such a cell is called a femto cell or a pico cell. In this paper, the concept of private base station should include various small wireless base station equipment, such as indoor office equipment, and can also include traditional wireless base station equipment covering a larger area. However, as described above, the UEs in the system have limited access rights to these dedicated radio base station devices.

In addition, although 3GPP and E-UTRAN are taken as examples in this paper, the present invention can also be applied to any radio access technology well known to those skilled in the art. In this document, "base station" generally refers to any network node that covers a network cell, such as a radio base station, Node-B Node B (NB), evolved Node B (eNB) and other similar network nodes. In addition, "UE" here generally refers to any mobile entity that can communicate with this type of base station, such as mobile station (MS), UE and other entities. The "dedicated cell reselection" herein is used for the UE to perform cell reselection on a dedicated cell.

Figure 1 is a schematic diagram of an example of 3G E-UTRAN. The framework of E-UTRAN is relatively simpler than that of UTRAN. As shown in Figure 1, the central radio network controller (Radio Network Controller, RNC) used to control multiple NBs is removed in E-UTRAN, and only two node types are defined, namely eNB and access gateway (MME /SAE). The eNB belongs to the E-UTRAN network, while the MME/SAE gateway belongs to the Evolved Packet Core (EPC) network. The X2 interface is used between eNBs, and the S1 interface is used between the eNB and the MMS/SAE gateway. Universal Mobile Telephony System (UMTS) adopts a similar network architecture, especially in the evolution of High Speed Packet Access (HSPA) system, RNC and NB are merged into the same node.

When the UE roams in the idle mode in the network, it selects the most suitable cell to camp on by measuring the determined cell.

When the cell selected by the UE belongs to another tracking area (Tracking Area, TA) instead of the tracking area where it currently resides, the UE sends a TA update (TA Update, TAU) to its core network (Core Network, CN) The request information is used to inform the CN that the UE has changed its coverage area.

The concept of dedicated base stations for Closed User Groups (CUG) brings a new direction to cellular network access. In this article, "limited access rights" refers to these CUGs. There may be a large number of cells covered by private base stations in the same area, which is also covered by public base stations in a normal public cellular network. However, the UE only has access to one or some of these private base stations. Since the required information is UE specific and not applicable to all UEs, the solution of broadcasting neighbor cell lists in UTRAN cells is not attractive. Accessing a dedicated base station by broadcasting information required by a large number of UEs will generate a large amount of system signaling overhead, because broadcasting is a very inaccurate method for transmitting UE-specific information.

In the Global System for Mobile communication (GSM), the Cordless Telephony System (CTS) has proposed the concept of small household equipment, as described in [5]. (The list of references is at the end of this specification.) Here, the mobility management of these mobile stations wanting to access the CTS cell is controlled by the UE, while the GSM or CTS system is preferred, which can be manually or in six different modes Automatic configuration.

Literature [3] proposes a method to solve CUG restricted access, that is, to formulate a list of TAs that the UE is allowed to access, and make the private base station send information about its access status, that is, whether it is configured as public access or restricted access. One drawback of this solution is that there may be a large number of private base stations in the system and thus cause the system to exhaust its identifiers.

Document [2] introduces the problem of identifiers. The soft difference between the tracking area code (Tracking Area Code, TAC) and the cell identifier makes the number of bits of the TAC depend on the number of cells contained in the TA.

However, the background art solutions presented above have the problem that in order for a UE to only access private base stations for which it has authority, a large amount of idle mode detection and searching of private base stations and other signaling needs to be performed.

In addition, in the background technology, broadcasting of neighbor cell lists (Neighbor Cell Lists, NCLs) between cells requires signaling overhead. Because the network contains a large number of private cells, this approach will produce a large number of signaling expenses. The neighbor cell list containing all these dedicated cell information may be very large and will generate a lot of signaling overhead. Different UEs have access rights to different private base stations, and only the information about the cells they can access is useful to UEs, so most of the information in the signaling is useless to most UEs.

Contents of the invention

The purpose of the present invention is to solve the problems involved in the above-mentioned private cell reselection.

The object of the present invention is to provide a private cell reselection method which requires less measurement, search and signaling compared to the prior art private cell reselection method.

The object of the present invention is achieved as follows: a UE-side method for UE-specific cell reselection, wherein, only when the UE is adjacent to a private base station with access rights, the UE performs a dedicated cell reselection search, here, adjacent Degree detection is based on information about the UE and its relationship to the private base station.

The object of the present invention is achieved in this way: a network node side method for UE private cell reselection, wherein the network node and the pair of private base stations have access rights only when the UE is adjacent to the private base station to which it has access rights The UE communicates about the private cell reselection search, where the proximity detection is based on information about the UE and its relationship with the private base station.

The object of the present invention is achieved in the following way: a UE for performing UE-specific cell reselection, wherein the UE is used for performing a dedicated cell reselection search only when the UE is adjacent to a cell with access rights, where Proximity detection is based on information about UEs and their relationship to private base stations.

The object of the present invention is achieved in this way: a network node for performing UE-specific cell reselection, wherein the network node is used for: only when the UE is adjacent to a private base station for which it has access rights, said network node and the pair A UE having access rights to a private base station communicates with respect to a private cell reselection search, where proximity detection is based on information about the UE and its relationship to the private base station.

The object of the present invention is achieved in this way: a system for performing UE-specific cell reselection, comprising:

- a UE for performing a private cell reselection search only if said UE is adjacent to a private base station to which it has access rights;

- A network node for communicating with a UE for a private cell reselection search only if the UE is in proximity to a private base station to which it has access rights; here proximity detection is based on information about the UE and its relationship to the private base station.

The object of the present invention is also achieved by a computer program and a computer program product for performing the method of the present invention.

The characteristic of the private cell reselection of the present invention is that the search of the private base station is based on the proximity to the private base station that the UE has operation authority, and the proximity detection is based on the information of the UE and its relationship with the private base station.

The advantage of this is that when the UE is in an idle state, unless it is adjacent to a cell that it has access rights to, the UE does not perform cell reselection search, measurement, and signaling interaction with the private base station. Also, the UE can determine whether it is adjacent to the private base station without broadcasting a large number of NCLs in the cell. This substantially reduces the amount of search, measurement and other signaling performed by the system.

In one embodiment of the invention, proximity detection is performed by the UE.

In one embodiment of the invention, proximity detection is performed by a public base station.

In one embodiment of the invention, proximity detection is performed by a private base station.

In one embodiment of the present invention, the proximity detection is based on the cell relationship between the private cell covered by the private base station that the UE has access rights to and its neighboring public cells or other neighboring private cells. The advantage is that the proximity detection can be effectively performed by using the cell relationship information, and in normal operation, the cell relationship information can be easily collected through the UE or the network.

The detailed embodiments and the advantages of private cell reselection in the present invention will be illustrated with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of an overall architecture of LTE.

Fig. 2 is a schematic diagram of cell relationship information.

Fig. 3 is a schematic diagram of changes in cell relationship information after public network reconfiguration.

Fig. 4 is a schematic diagram of coverage positions.

Detailed ways

In a system including a private base station, an effective process that can effectively handle the access of the UE to the private base station is required, especially the measurement and search of the private base station, and the processing of signaling in the network.

Document [1] indicates that some researchers have begun to study the requirements of dedicated base stations in LTE. Specifically, the requirements on idle mode mobility in document [1] are listed below.

I If the UE is not allowed to use (use) a private base station covering a particular cell, UEs in LTE idle state should be prevented from accessing that particular cell.

II If the UE is not allowed to access a private base station covering a particular cell, camping of UEs in LTE idle state in that particular cell should be avoided.

III If the UE is not allowed to access (access) a specific private base station, the number of measurements for the private base station by the UE in the LTE idle state should be reduced.

IV If the UE is not allowed to access (access) a specific private base station, the number of measurements of the private base station by the UE in any cell reselection state in another radio access technology (Radio Access Technology, RAT) should be reduced .

V The reselection parameters of the UE allowed to access the cell can be set, so that the UE can distinguish the priority of the private base station.

The analysis of the literature [5] shows that there is no method for preventing the UE from searching for the CTS cell when the UE is not located in the vicinity of the CTS. Therefore, the solution proposed in this document does not meet the requirements of IV above.

In addition, the literature [2] does not propose any method to control how to reduce the measurement of the private base station. Therefore, the solution proposed in this document does not meet the requirements of III-IV above.

The UE here can communicate with two radio communication systems, one system includes a dedicated base station, and the other system includes a public base station. The public base station refers to an ordinary base station without any access restriction and has a wide coverage area, such as a large-area macro cell in an ordinary public communication system. In the coverage area of such a large-area macro cell, hundreds of private cells may be included. In order to avoid the overload of the broadcast channel covering the macro cell, it is further required that the proximity detection cannot only rely on broadcasting the neighbor cell list. Broadcasting the neighbor cell list is a traditional method for controlling cell reselection in the background art.

According to the present invention, the UE cell reselection procedure in idle mode includes the use of the neighbor parameter. For cell reselection, the UE should search for a private cell based on the proximity to private base stations it can access. So according to the invention, the search for private base stations is based on the proximity to private base stations to which the UE has access rights. In addition, according to information about the UE and its relationship with the private base station, it can be determined whether the UE is adjacent to the private base station. In other words, the decision is based on information related to the particular UE in question. Therefore, since broadcasting a large NCL requires a lot of signaling, the overhead of the cell can be significantly reduced without increasing the signaling overhead of NCL broadcasting in the cell.

According to different embodiments of the present invention, the proximity parameter for private cell reselection may be detected by UE, private base station, public base station or by other methods. If the UE itself does not detect the proximity parameter, the device that has detected the parameter needs to indicate the proximity parameter to the UE.

According to the present invention, a proximity indication is an indication that a UE having access rights to a particular private base station approaches or enters a particular base station in order to camp on or conduct an active mode session, or both coverage.

According to the present invention, a cell reselection search is performed on a private base station to which the UE has access rights only when the UE is adjacent to the private base station.

This has the advantage that cell reselection searches, measurements and other signaling are not wasted on private base stations unless a UE in idle mode is close to a private base station to which it has access rights. In this way the signaling used in search, survey and other systems is substantially reduced. Therefore, the idle mode cell reselection procedure of the present invention satisfies the above-mentioned requirements of I-V.

There may be many different proximity detection mechanisms in the system. As proximity detection can be hierarchical, primary proximity mechanisms can trigger the use of more granular mechanisms. For example, more granular mechanisms could be used after identification such as a location area, tracking area or routing area.

In one embodiment of the present invention, the proximity detection is performed by the UE, that is, the UE detects the proximity of the private base station with which it has access rights. Detection is based on storing and identifying information about cells that are adjacent or in close proximity to a particular private cell. Therefore, the UE will store the cell information and cell relationship information of the dedicated cell and its surrounding cells. These information may be stored in a Subscriber Identity Module (Subscriber Identity Module, SIM) card or other storage devices of the UE. This information may be established by reading information from neighboring cells in active mode when the UE camps on or leaves the private cell.

On the other hand, based on the operation and maintenance (Operations and Maintenance, O&M) network mode, the network can provide the information to the UE. When the network O&M mode changes, or when the customized information changes, the information can be updated in the UE: for example by using the short message of "SIM-toolkit (SIM-toolkit)" (not often used), customized Short message (mobility based) or short message on tracking area update (when UE enters TA with dedicated cell).

Fig. 2 is an example of the content contained in the cell relationship information. As shown in Figure 2, the UE stores information related to private base stations that it is allowed to access, such as PBS-3 in Figure 2, information related to neighboring public cells, macro cells mNB-1 and mNB-2, and UE Information about other private base stations without access rights, such as PB2 to PB5.

Cell relationship information can also be stored in network nodes, such as public base stations or private base stations.

No matter where the cell relationship information is stored, it may contain information related to at least one private base station that the UE has access rights to, information related to at least one adjacent private base station, information related to at least one adjacent public base station, and information related to at least one adjacent public base station. Logical Cell Value (LCV), carrier frequency, cell ID, or public public land mobile network (PLMN) related information.

When the UE roams in the network, it keeps track of neighboring cells. When the UE recognizes one or several cells defined in its cell relationship mapping table, the UE starts to search for a private base station that it has access rights to. In other words, when the UE finds itself in any cell adjacent to the private base station it has access rights to, the UE can analyze its own cell relationship information to conclude that the UE is near the private base station it has access rights to. At this time, the UE starts to perform cell reselection search on the private base station.

The advantage of detecting proximity based on information related to cells and cell relationships is that the UE or the network can easily collect this information during normal operation, thereby making proximity detection more effective.

On the other hand, the UE may use a positioning technology to detect the proximity of a dedicated base station that it has access to, such as a Global Position System (Global Position System, GPS) positioning technology, or a Galileo positioning technology. The advantage of this is that it is very easy to get precise geographic location.

It is also possible that the UE uses other UE application technologies to detect the proximity. If the UE is capable of running other application technologies such as Wireless Local Area Network (WLAN), Bluetooth or similar technologies, the UE can use these technologies to detect proximity. For example, the UE can identify a known short-range wireless network, such as a Bluetooth or WLAN network, and then use this identification result in proximity detection. The UE may also run UE-specific applications that provide the UE with information about its proximity to a private base station, for example, when the UE can be used as a remote controller to open garages, front doors, or other remotely controlled devices .

Due to the addition of new cells or other cell layout reconfigurations, the cell plan of the public network also sometimes needs to be updated. When this happens, the relationship between the private cell and the public network cell may also change, as shown in FIG. 3 .

It can be seen from Fig. 3 that before and after cell reconfiguration, private cells and different cells in the public network are overlapped together, and cell 1 and cell 2 are shown in the figure.

In the situation shown in Figure 3, the UE may try to use its cell relationship information to search for a private base station, but since the layout of the cell has changed and the proximity indication is not invoked, the UE will not search for a private base station.

In an embodiment of the present invention, after the cell layout is reconfigured, the broadcast cell information includes the new cell information and the cell information of the pre-configured cell, that is, the old cell information. This additional information will be broadcast for a period of time so that UEs know which cell information they need to update related to them.

If the UE does not obtain the additional information within this period of time, the UE has to manually select a dedicated cell and update the cell relationship information. This method can also be used when the owner of the private base station moves the private base station at home or in a building, which also changes the relationship between the cells.

In the present invention, the advantage of keeping the cell relationship information updated is that the proximity detection can always be based on the continuously updated cell relationship information.

According to an embodiment of the invention, a public network node may initiate or perform proximity detection.

Typically, there are a large number of UEs in idle mode in the network, and these UEs perform limited information interaction with the network. Therefore, when there are a large number of UEs in idle mode, a large amount of signaling load should be avoided.

Therefore, according to an embodiment of the present invention, when a UE is registered in a TA having the same geographical coverage area as a private cell, the network provides the UE with search parameters to command the UE to search for a private cell to which it has access rights. A better method is to use the TA update (TAU) response message in the network.

The advantage of using TA signaling to provide search parameters is that existing signaling interactions can be utilized, for example, tracking area update signaling is existing signaling in the system.

However, since the coverage area of a TA is quite large and the UE searches for its private cell throughout the TA, battery power efficiency cannot always be very high.

According to an embodiment of the present invention, the CN further sends a request to the UE as a response to the TAU. This request requires the UE to send additional TAU information when entering a specific cell of the TA (or any cell in some list, the list contains multiple cells). When a UE enters a cell that is close to or directly adjacent to a dedicated cell that the UE has access rights to, it is required to send additional TAU information in this cell. The additional TAU message is responded to by the last TAU response message from the network, which includes search parameters ordering the UE to search for a specific private cell.

Further, the network can establish and update cell relationship information for the private cell according to measurement reports from UEs in active mode located near the private cell. Especially neighbor cell measurement reports from UEs are very useful for maintaining cell related information for proximity detection, where the UE belongs to a closed user group that is allowed to use private base stations.

As mentioned above, for each UE, network-controlled proximity detection or network-controlled cell reselection has the advantage of being very easy to implement in combination with closed user groups.

A hybrid approach can also be used to perform proximity detection. For the private base stations that the UE can access, the network provides the UE with cell relationship information related to the surrounding cells of the private cell in the TAU update response information. Thus, it is the UE's responsibility to decide when to start the search for the private base station.

The advantage of the hybrid approach is that the signaling overhead is smaller than purely network-controlled proximity detection. At the same time, the UE does not need to store network information and possibly closed user group information for a long period of time, thereby reducing the risk of outdated information stored by the UE.

According to an embodiment of the present invention, the network node performing the proximity detection may also be an external electronic entity identifying users present within the coverage area of the private cell. For example, as an external electronic entity with a proximity detector function, it could be an alarm such as motion detector, alarm start/stop, garage entry and exit activation, electronic key system, vehicle detection, refrigerator door open detector, sound detector , stereo system/radio receiver/personal computer/light detector or other similar devices.

Those skilled in the art may know that there are a large number of external electronic entities that can be used to determine the location of the UE user, and these electronic entities may include various sensors. Those skilled in the art know that besides the electronic entities mentioned above, sensors in other external electronic entities can be easily used to implement the present invention.

The proximity detection indication generated by the external electronic entity may trigger the network to send additional information to the UE, which information is related to the availability of the private cell. As described above, the UE can use these information to determine whether to search for and measure a private base station that the UE has access rights and is close to the location of the UE.

The advantage of using an external electronic entity for proximity detection is that it is possible to use inexpensive sensor technology that is already in use in many homes, or that will be available in many home devices in the future.

In embodiments of the present invention, proximity detection may also be performed by a dedicated base station. In the embodiment of the present invention, the private base station provides detection-related information to the UE via the public base station, and the method provided is the same as that of the public base station for detecting proximity. The private base station notifies the UE that the proximity has been detected via the public base station, and commands the UE to start searching for the private base station.

Currently, the ownership of private base stations is unclear. One possibility is that homeowners also have dedicated base stations placed in their homes. Owners cannot be expected to perform complex network planning and configuration work on private cells like network operators. Therefore, from the perspective of owners, private cells need to be able to configure autonomously. Since the owner can place the private base station in any suitable place, from the perspective of the network operator, the coverage of the private cell is not planned.

Figure 4 shows an example where there are two private cells (cell 1 and cell 2) and one public cell (cell 3), where the private cell is covered by a private base station.

A private cell may not have a direct coverage relationship with nearby cells, such as private cell 2 in FIG. 4 , that is, it may not have a direct neighboring cell. This can be the case when a dedicated base station is placed in the basement of a house.

In Fig. 4, when a UE in an idle state roams from cell 3 to cell 2, it will not be able to keep in touch with the network for a period of time. The network cannot page the UE either, that is, the UE is "not in the coverage area". In a public communication system, when the UE finds itself out of the service area, it will try to find its original cell (cell 3) for a period of time, and then perform a search for other cells.

According to an embodiment of the present invention, the UE performs proximity detection based on the status of such a public cell coverage condition. In particular, as a special case of the proximity detection, when the UE is not in the service area, the UE preferentially detects a dedicated cell that it knows and has access rights to. More precisely, the UE preferentially searches for private cells that it knows have no immediate neighbors.

According to the method for using the cell relationship information described above, if the UE has further knowledge of surrounding cells, the UE can use these knowledge to further determine which cell to search for.

Document [4] proposes to send explicit cell priority to UE. In an embodiment of the invention, this idea is extended to also include a proximity indication as selection priority.

According to the embodiment of the present invention, by including the coverage condition state parameter in the proximity detection, compared with the case where the UE does not have any search target clues, the speed at which the UE re-acquires the service may be significantly accelerated at this time.

In the embodiment of the present invention, the time interval between two private cell reselection searches depends on the distance between the UE and the private base station. When the distance is small, the time interval is relatively short, and conversely, when the distance is large, the time interval is relatively long.

In the embodiment of the present invention, the UE is indicated or stored additional information related to the coverage condition of the private cell, that is, whether the private cell is "servable" or "unserviceable". When the UE is in the coverage of other cells and the private cell is "unserviceable", the UE uses these additional information so as not to search for the private cell. Therefore, according to an embodiment of the present invention, when a private base station is "unserviceable", unnecessary searches need not be performed.

Further, when the private cell is configured in an interference reduction mode, the private base station may not be visible to the UE.

According to the embodiment of the present invention, the UE may already know that it is in the vicinity of the private base station, but still tries to find the discontinuous transmission (DTX) mode of the private base station, and sends a random access burst to the private base station, and the random access burst may With a special preamble, turn the private base station into normal working mode. The method described above may be used when the private base station is "unserviceable", if the private base station is turned off or is in some other power conservation mode at the time.

In particular, this is important in case a UE needs to send an emergency call to an unservable private base station. Using embodiments of the present invention, the possibility of making emergency calls within a private cell is increased.

Accordingly, the present invention relates to a system for private cell reselection by a user equipment (UE) in idle mode in a public network comprising at least one public base station covering the public cell, the UE also being able to communicate with the private network For communication, the private network includes at least one private base station covering the private cell, and the UE has limited access rights in the private network; where:

- a UE configured to: perform a private cell reselection search only when the UE is adjacent to a private base station to which it has access rights;

- a network node for communicating with a UE for a private cell reselection search only when the UE is in the vicinity of a private base station to which it has access, the UE having access to a private cell;

Here the proximity detection is based on the information of the UE and its relation to the private base station.

The invention also relates to corresponding methods and devices for UEs and network nodes performing cell reselection.

The UE and the network node performing dedicated cell reselection in the present invention can be used to perform any steps of the method of the present invention. The only requirement is that this step involves the UE or network node.

Those skilled in the art can modify the private cell reselection method of the present invention according to the embodiments described above.

references

[1] 3GPP TSG RAN, RP-070209, "Requirements for LTE Home eNodeBs"

[2] 3GPP TSG RAN WG2, R2-071349, "Use of tracking area-and cell identity for private networks/home cells"

[3] 3GPP TSG RAN WG2, R2-071428, "Use of home & private eNBs"

[4] PCT/CN2007/000037 Patent application, "Cell search in a cellular communications system"

[5] 3GPP TS 42.056 v6.0.0, "GSM Cordless Telephony System (CTS), Phase 1; Service description; Stage 1"

Claims (66)

1. A method for reselecting a private cell by a user equipment UE in an idle mode in a public network, the public network including at least one public base station covering a public cell, and the UE can also communicate with the private network, the The private network includes at least one private base station covering the private cell, and the UE has limited access rights in the private network; It is characterized in that when the UE is adjacent to a cell with access rights, the UE only performs a dedicated cell reselection search, and the detection of the proximity is based on the information of the UE and its relationship with the private base station. 2. The method according to claim 1, characterized in that, based on the cell relationship between a private cell covered by the private base station and other public or private cells adjacent to the private cell, the The one that performs the proximity detection. 3. The method according to claim 2, characterized in that said cell relationship is detected and stored when said UE is in active mode. 4. The method of claim 3, wherein the cell relationship is based on a measurement report from the UE. 5. The method according to claim 2, characterized in that said cell relationship is detected and stored when said UE is in idle mode. 6. The method according to claim 2, wherein when the cell plan of the private or public cell is updated, the UE receives the cell information broadcast of the public base station in the public network, and the cell information broadcast includes new cell information and the old cell information, the UE uses the new cell information and the old cell information to update the stored cell relationship. 7. The method according to claim 2, wherein the UE controls whether the stored cell relationship needs to be updated, and if the stored cell relationship needs to be updated, the UE requests the public base station in the public network to send cell information; The cell information broadcast includes new cell information and old cell information, and the UE uses the new cell information and old cell information to update the stored cell relationship. 8. The method according to claim 2, wherein the UE controls whether the stored cell relationship needs to be updated, and if the stored cell relationship needs to be updated, the UE collects cell information and uses the cell information to update the stored community relations. 9. The method according to claim 2, wherein the public relations base station notifies the UE whether the stored cell relationship needs to be updated, and if the stored cell relationship needs to be updated, the UE collects cell information and uses the cell information Update the stored cell relationship. 10. The method according to claim 2, wherein the cell relationship includes information of at least one of the following parameters or entities: at least one private base station to which the UE has access rights; at least one adjacent private base station, at least one Adjacent public relations base stations, logical cell value LCV, carrier frequency, cell ID, public land mobile network PLMN. 11. The method according to claim 1, further comprising: the detection of the proximity of the private base station is performed by the UE. 12. The method according to claim 11, further comprising, said detecting is based on a state of a coverage condition of said at least one public cell. 13. The method according to claim 12, wherein the status includes whether the geographical area where the UE is present is covered by at least one of the public cells. 14. The method according to claim 13, further comprising, when the UE enters an area not covered by at least one of the public cells, and the area is adjacent to the private base station, setting the UE to search Dedicated base station. 15. The method of claim 12, wherein the UE stores information related to the status. 16. The method of claim 12, wherein the UE receives the status information from a public base station in the public network. 17. The method of claim 11, wherein the detecting is based on information provided to the UE by a public base station in the public network. 18. The method of claim 17, wherein said public base station orders said UE to perform said proximity detection. 19. The method of claim 11, wherein said detecting is based on information provided by location software. 20. The method of claim 19, wherein said location software comprises Global Positioning System (GPS) software. 21. The method of claim 19, wherein said location software comprises Galileo positioning system software. 22. The method of claim 11, wherein said detecting is based on discovery of an electronic device. 23. The method according to claim 22, wherein the electronic device comprises any one of the following electronic devices: a UE device, a local area wireless network, including a Bluetooth network or a wireless local area network (WLAN). 24. The method of claim 1, wherein said detection of proximity to a private base station is performed by a public base station in a public network. 25. The method of claim 24, wherein the detection-related information is provided to the UE by the public base station. 26. The method of claim 25, wherein the public base station notifies the UE that the proximity has been detected. 27. The method of claim 25, wherein the public base station instructs the UE to search for a private base station. 28. The method according to claim 25, wherein when the UE enters a specific public cell in a tracking area (TA), the public base station instructs the UE to send an additional tracking area update (TAU) information; the public In response to the TAU, the base station commands the UE to search for a designated private base station. 29. The method of claim 24, wherein the location of the UE is detected by using an external electronic entity. 30. The method of claim 29, wherein the external electronic entity comprises any of the following electronic entities: Alarm entity, including burglar alarm, motion detector, alarm activation, alarm deactivation; Household entities, including door or garage entry activations, kitchen equipment activations, electrical equipment activations. 31. The method of claim 1, wherein said detection of said proximity to a private base station is performed by said private base station. 32. The method according to claim 31, wherein the detection-related information is provided to the UE by the private base station via a public base station. 33. The method according to claim 32, wherein the information is used to notify the UE that the proximity has been detected. 34. The method of claim 32, wherein said information is used to order said UE to search for a private base station. 35. The method according to claim 1, wherein when the UE enters a specific public cell of TA, the UE sends tracking area update TAU information, and as a response to the TAU information, the public base station sends The information about the relationship The cell relationship is the relationship between the private cell covered by the specific private base station and other public cells or private cells adjacent to the private cell. 36. The method according to claim 1, wherein when the private base station is in interference reduction mode and the UE is adjacent to the private base station, the private base station detects a discontinuous transmission (DTX) mode and sends a random access An incoming pulse turns the private base station into a normal operating mode. 37. The method of claim 1, wherein the time interval between two said private cell reselection searches depends on the distance between said UE and said private base station. 38. The method of claim 37, wherein said time interval is relatively short when said distance is short. 39. The method of claim 37, wherein said time interval is relatively long when said distance is long. 40. The method of claim 1, wherein the private network and the public network are of the same type. 41. The method of claim 1, wherein the private network and the public network are different types of networks. 42. A method for a network node to perform private cell reselection on a user equipment UE in idle mode in a public network, the public network including at least one public base station covering the public cell, and the UE can also communicate with the private network , the private network includes at least one private base station covering a private cell, and the UE has limited access authority in the private network; It is characterized in that only when a UE having access rights to a private cell is adjacent to the private base station, the network node communicates with the UE on private cell reselection search, and the detection of the proximity is based on the UE and its connection with the private base station. Information about the relationship between the private base stations. 43. The method according to claim 42, characterized in that said network node provides information to said UE; said UE performs proximity detection based on said information. 44. The method according to claim 43, wherein when the cell plan of the private or public network is updated, the information provided to the UE includes new cell information and old cell information, and the information is provided by the network Sent when a node sends cell information. 45. The method of claim 44, wherein the cell information transmission is requested by the UE. 46. The method according to claim 44, wherein the sending of the cell information includes broadcasting transmission. 47. The method according to claim 43, characterized in that said network node provides information related to the status of coverage conditions of at least one common cell. 48. The method of claim 42, wherein said network node performs said proximity detection. 49. The method of claim 48, wherein information related to the detection is provided to the UE. 50. The method according to claim 49, characterized in that said network node notifies said UE that proximity has been detected. 51. The method according to claim 49, characterized in that said network node orders said UE to search for a private base station. 52. The method of claim 48, wherein the location of the UE is detected using an external electronic entity. 53. The method of claim 52, said external electronic entity comprising any one of the following electronic entities: Alarm entity, including burglar alarm, motion detector, alarm activation, alarm deactivation; Household entities, including door or garage entry activations, kitchen equipment activations, electrical equipment activations. 54. The method of claim 42, wherein said network node comprises said private base station. 55. The method of claim 42, wherein said network node comprises said public base station. 56. The method according to claim 55, wherein when the UE enters a specific cell in a Tracking Area (TA), the public base station commands the UE to send an additional Tracking Area Update (TAU) message. 57. A user equipment, UE, performing private cell reselection when in idle mode in a public network, said public network comprising at least one public base station covering a public cell, said UE being capable of communicating with a private network, said private network comprising at least one private base station covering a private cell, the UE having limited access rights in the private network; It is characterized in that when the UE is adjacent to a cell with access rights, it performs a dedicated cell reselection search, and the detection of the proximity is based on specific information about the UE and its relationship with a dedicated base station. 58. A network node for performing private cell reselection on a user equipment UE in an idle mode in a public network, the public network including at least one public base station covering a public cell, the UE can communicate with the private network, the The private network includes at least one private base station covering a private cell, and the UE has limited access rights in the private network; It is characterized in that only when a UE having access rights to a private cell is adjacent to the private base station, the network node communicates with the UE on private cell reselection search, and the detection of the proximity is based on the UE and its connection with the private base station. Specific information on the relationship between said private base stations. 59. A network node as claimed in claim 58, characterized in that said network node comprises said private base station. 60. A network node according to claim 58, characterized in that said network node comprises said public base station. 61. A system for performing private cell reselection on a user equipment UE in idle mode in a public network, said public network comprising at least one public base station covering a public cell, said UE can communicate with a private network, said The private network includes at least one private base station covering a private cell, and the UE has limited access rights in the private network; It is characterized in that it includes: The UE only conducts a private cell reselection search when in proximity to a private base station to which it has access rights; a network node for communicating with said UE about a private cell reselection search only when said UE is adjacent to said private base station; The detection of proximity is based on specific information of the UE and its relationship to the private base station. 62. A network node as claimed in claim 61, characterized in that said network node comprises said private base station. 63. A network node as claimed in claim 61, characterized in that said network node comprises said public base station. 64. A computer program, characterized in that it is realized by codes, and when the codes are run in a computer, it can cause the computer to execute any one of the methods in claims 1 to 56. 65. A computer program product comprising a computer readable medium and the computer program according to claim 64, the computer program being contained in the computer readable medium. 66. The computer program product of claim 65, wherein the computer readable medium comprises one or more of the following devices: read only memory ROM, programmable memory PROM, erasable programmable memory EPROM, flash memory, Chargeable erasable programmable memory EEPROM and hard disk.

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