WO2014012192A1

WO2014012192A1 - Network system with local cluster, central controller, micro base station and macro base station

Info

Publication number: WO2014012192A1
Application number: PCT/CN2012/000981
Authority: WO
Inventors: Jiangnan Chen; Hong Zhou; Xianjun XIONG
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2012-07-20
Filing date: 2012-07-20
Publication date: 2014-01-23
Also published as: CN104429111B; CN104429111A

Abstract

The embodiments of the present invention provide a network system with local cluster, central controller, micro base station and macro base station; the network system includes a macro base station and a plurality of micro base stations; the network system further includes: one or more central controllers, configured to provide base station collaboration, resource management, interference and power coordination, or synchronization for the plurality of micro base stations. Through the embodiments of the present invention, the overall system performance and radio resource utilization have been improved.

Description

NETWORK SYSTEM WITH LOCAL CLUSTER, CENTRAL

CONTROLLER. MICRO BASE STATION AND MACRO BASE

STATION

FIELD OF THE INVENTION

This application relates to communication technology and in particular, to a network system with local cluster, central controller, micro base station and macro base station.

BACKGROUND

Cellular macro cell coverage with macro cell base station for 3GPP technology has been around for many years, macro cell coverage has been the main technique for providing cellular services. In order to increase cell capacity, small cell concept has been brought up where clusters of smaller cell size coverage under the macro cell coverage were deployed with the names for the base stations such as pico cell, micro cell, femto cell, etc.

On the other hand, WiFi (Wireless Fidelity), example of WLAN(Wireless Local Area Network) technology, is a small cell technology along with 3 GPP technologies such as GSM (Global System for Mobile Communication), UMTS (Universal Mobile Telecommunications System), and LTE (Long Term Evolution). How to deploy small cell base stations/WiFi AP (Access Point)s under the macro cell coverage is the topic for prior art.

However, the applicant found that the existing topology of small cell/WiFi deployment has no mechanism of connecting these small cell base stations per cluster of deployment, direct association among the small cell base stations under the macro cell coverage, or managing a local cluster specific of small cell base stations.

SUMMARY

Embodiments of the present invention pertain to a network system with local clusters, central controller, micro base station and macro base station.

According an aspect of the embodiments of the present invention, there is provided a network system with local cluster, the network system includes a macro base station and a plurality of micro base stations; the network system further includes:

one or more local central controllers, configured to provide base station collaboration, resource management, interference and power coordination, or synchronization for the plurality of micro base stations;

Wherein the one or more central controllers are connected to the macro base station; and the central controller is connected to multiple micro base stations through wire or wirelessly so that the local cluster is formed.

According another aspect of the embodiments of the present invention, there is provided a central controller, applied in a network system with local cluster, the central controller is connected to multiple micro base stations so that the local cluster is formed;

the central controller includes:

a first receiving unit, configured to receive a request message from one of the multiple micro base station;

a controlling unit, configured to provide base station collaboration, resource management, interference and power coordination, or synchronization based on the request message;

a first sending unit, configured to send a response message to the micro base station.

According another aspect of the embodiments of the present invention, there is provided a micro base station, applied in a network system with local cluster, the micro base station is connected to a central controller;

the micro base station includes:

a second sending unit, configured to send a request message to the central controller; wherein the request message is used for requesting base station collaboration, resource management, interference and power coordination, or synchronization;

a second receiving unit, configured to receive a response message from the central controller.

According another aspect of the embodiments of the present invention, there is provided a macro base station, applied in a network system with local cluster, the macro base station is connected to one or more central controllers, the central controller is connected to multiple micro base stations so that the local cluster is formed;

the macro base station includes:

a third receiving unit, configured to receive a request message from the central controller.

a third sending unit, configured to send a response message to the central controller.

The advantages of the present invention exist in that: simplify the connection of small cell base stations by connecting micro base stations via a central controller; and the overall system performance and radio resource utilization have been improved.

These and further aspects and features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the appended claims.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. To facilitate illustrating and describing some parts of the invention, corresponding portions of the drawings may be exaggerated in size, e.g., made larger in relation to other parts than in an exemplary device actually made according to the invention. Elements and features depicted in one drawing or embodiment of the invention may be combined with elements and features depicted in one or more additional drawings or embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views and may be used to designate like or similar parts in more than one embodiment.

BRIEF DESCRIPTION OF THE DRAWING

The drawings are included to provide further understanding of the present invention, which constitute a part of the specification and illustrate the preferred embodiments of the present invention, and are used for setting forth the principles of the present invention together with the description. The same element is represented with the same reference number throughout the drawings.

In the drawings:

Figure 1 is a schematic diagram of the network system of an embodiment of the present invention;

Figure 2 is a topology diagram of the network system of an embodiment of the present invention;

Figure 3 is another topology diagram of the network system of an embodiment of the present invention;

Figure 4 is another topology diagram of the network system of an embodiment of the present invention;

Figure 5 is another topology diagram of the network system of an embodiment of the present invention;

Figure 6 is another topology diagram of the network system of an embodiment of the present invention;

Figure 7 is a functional diagram of the network system of an embodiment of the present invention;

Figure 8 is a schematic diagram showing adjusting Tx power for UE re-association with access points;

Figure 9 is a schematic diagram showing dynamic beam switching of access points;

Figure 10 is a schematic diagram showing time synchronization of access points;

Figure 11 is a schematic diagram of the central controller of an embodiment of the present invention;

Figure 12 is a schematic diagram of the micro base station of an embodiment of the present invention;

Figure 13 is a schematic diagram of the macro base station of an embodiment of the present invention.

DETAILED DESCRIPTION

The many features and advantages of the embodiments are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the embodiments that fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the inventive embodiments to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope thereof.

The preferred embodiments of the present invention are described as follows in reference to the drawings.

Nowadays, the existing topology usually refers to UMTS/LTE network, the existing topology allows small cell base stations under the coverage of a macro cell base station to be logically connection via a "mesh" format, which means that all the small cell base stations are all equally deployed at the "same level" of the macro cell base station. All the small cell base stations have the same "right" to exchange information between small cell base stations and macro cell base station.

The existing topology of small cell/WiFi deployment is usually without a "local" central control point to connect these small cell base stations per cluster of deployment. And the existing technology does not show any direct association among the small cell base stations under the macro cell coverage via the central control point; and without direct association for the small cell clusters and the macro cell base station under the macro cell coverage. Furthermore, the existing technology does not have a capability to manage a local cluster specific of small cell base stations.

Furthermore, there could be many small cell base stations/WiFi APs under the coverage of a macro cell, and they are all deployed under the same level (no hierarchy) and equally connected to the EPC (Evolved Packet Core) or RNC (Radio Network Controller) directly, and directly controlled by the EPC or the RNC.

The lack of a local control point for these small cell base stations/WiFi APs makes the collaborations and communications harder and complex, and the same information might need to be sent to many others without knowing if there is a need to send these information, and causing information exchange efficiency issues among these links, and wasted bandwidths.

The lack of a local central control point among a cluster of small cell base stations also cause problem of lack of central management of resources of each of the small cell base stations, this makes it hard to improve the overall system level performance and radio resources utilizations.

In the present application, local clusters of small cell base stations WiFi APs (each usually convers a contiguous area within a cluster) are deployed with an architecture of spoke or star format, with mixture of wired or wireless connections to a local central control point, under the macro cell coverage, and associated with the macro cell base station by direct or indirect links, and exchange corresponding information to facilitate operations and collaborations of the macro and small cell base stations, to achieve the purposes of capacity increase and better end user experience.

Embodiment 1

The embodiment of the present invention provides a network system with local cluster. Figure 1 is a schematic diagram of the network system of an embodiment of the present invention.

As shown in Figure 1, the network system includes: a macro base station 101, a plurality of micro base stations 102; the network system further includes: one or more central controllers 103, the central controller 103 may one example of the local central control point; Wherein the central controller 103 is used to provide base station collaboration, resource management, interference and power coordination, and synchronization for the plurality of micro base stations; the one or more central controllers are connected to the macro base station; and each central controller is connected to multiple micro base stations so that a local cluster is formed.

As shown in Figure 1, each central controller 103 is connected to some micro base stations in star topology or spoke topology. Please note that this "star or spoke" format is different from the "mesh" format adopted by the existing technology.

In the present application, the micro base station may be a pico base station, or a femto base station, or a WiFi AP (acesss point). However, it is not limited thereto, and particular manner may be determined as actually required.

In the present application, the connection between the central controller 103 and the micro base stations 102 is cabled, or wireless or both of them.

In should be note that it is only shown one cluster under the macro cell coverage in Figure 1. However, it is not limited thereto. In fact, there could be many clusters of small cell base stations (for example, hot spots) deployed under the macro cell coverage.

Also, there is only one cluster of small cell base stations to share the same cell site with the macro cell site (per sector if it is a sectorized macro site) (as shown in the Figure 1). The rest of clusters (not shown) under the macro coverage would be around the central controller, not necessarily at the same location as the macro site, but could be linked to the macro site remotely via cabled connections, so that information of various clusters could be shared with the macro site base station as well, through the central control point of the local clusters.

Figure 2 is a topology diagram of the network system of an embodiment of the present invention. As shown in Figure 2, a group of cheap nodes (micro base stations 102,such as WiFi APs) attached to the central controller 103 (such as local router or local gateway) with GE (Gigabit Ethernet) connections.

As shown in Figure 2, the central controller 103 is used to manage the WiFi nodes locally for traffic offload, load balancing, QoS management, local mobility management, interference management, etc. Furthermore, the transport link would need a higher capacity than usual in order to accommodate groups of WiFi traffic.

In this embodiment, the interconnection between the micro base stations 102 to the central controller 103 can be optical, or electrical, and can be cabled or wireless. The interconnection among the micro base stations can be mesh connected such that some of the micro base stations do not need any obvious cable connections back to the macro/micro/pico base stations.

In this embodiment, terminals are either dual mode or single mode and can access either cellular service or WiFi service or both. All APs may be concentrated at the macro/micro/pico base station and share the same power and backhaul resources as the macro/micro/pico base station has. All the AP nodes and the base station share the same backhaul bandwidth. All the AP nodes may be managed through the base station directly (by function module, for example software function module, on the base station), or through the base station backhaul to the network management box.

Figure 3 is another topology diagram of the network system of an embodiment of the present invention. As shown in Figure 3, the network system can be applied in UMTS, and the central controller is further connected to an Access Gateway (AG).

Figure 4 is another topology diagram of the network system of an embodiment of the present invention. As shown in Figure 4, the network system is applied in LTE system, and the central controller 103 is further connected to a Mobility Management Entity (MME) and a serving Gateway (S-GW).

As shown in Figure 4, AC (Access Controller) functions are split into two portions; wherein control portion is configured into MME and data portion is configured into S-GW.

In the present application, cheaper expansion with WiFi and limited cellular coverage is performed; this expansion would be lower cost comparing with integrated Micro/Pico and WiFi solutions. Local management of WiFi type of network is performed.

In the present application, WiFi network is visible, manageable, and maintainable. There is a lot higher throughput, offload macro network with unlicensed spectrum. And WiFi backhaul is simple Ethernet, usually cheaper than managed backhaul transport. Furthermore, the network system could cover the same area as the macro/micro/pico cell area with multiple AP nodes; and share the backhaul with base station, simplify the WiFi site requirement on WiFi AP backhaul.

In one embodiment, the central controller may be a plug-in of the macro base station. Figure 5 is another topology diagram of the network system of an embodiment of the present invention. As shown in Figure 5, the central controller is a Pico and WiFi controller and the Pico and WiFi controller is a plug-in of the macro base station.

In this embodiment, the Pico and WiFi controller may connect to muti-port switch, such as multi-port POE (Power Over Enthernet) switch, such that the Pico and WiFi controller is across multi-APs; and the Pico and WiFi controller may provide interference management, such as dynamic sector beam antenna selection, dynamic AP selection, multi-AP coordinated power adjustment & CCA (Clear Channel Assessment) adaptation, range extension, AP frequency management, macro-pico ICIC (Inter-Cell Interference Coordination).

Furthermore, As shown in Figure 5, the Pico and WiFi controller may connect to base control board, and the Pico and WiFi controller may provide the following functions: local AP networking, load balancing, inter- working with macro station, central network management (Local), and so on.

In another embodiment, the central controller may be an external unit of the macro base station. Figure 6 is another topology diagram of the network system of an embodiment of the present invention. As shown in Figure 6, the central controller is a Pico and WiFi controller and the Pico and WiFi controller is an external unit of the macro base station.

Figure 7 is a functional diagram of the network system of an embodiment of the present invention. As shown in Figure 7, the central controller (for example, Pico and WiFi controller) may perform collaboration management; the micro base station (such as Pico base station, WiFi AP) may perform scheduler/resource management or control management; and macro base station may perform scheduler/resource management.

In one embodiment, the central controller may be specifically used to reconfigure user equipment from one micro base station to another micro base station.

Wherein the central controller is used to adjust powers of the micro base stations; the user equipment is used to search the adjusted powers; and the user equipment disconnects from a micro base station and re-attaches another micro base station based on the adjusted powers.

In an implement, the central controller may utilize power and CCA threshold adjustment from multiple APs to mitigate interference. Figure 8 is a schematic diagram showing adjusting Tx power for UE re-association with access points.

As shown in Figure 8, if an UE is interfered severely associated with current AP (AP2). Then a central controller can reduce its Tx power to this UE and increase its CCA at the same time, such that the UE will de-associate with AP2. In the mean time, the central controller will increase its neighboring API 's Tx power, and reduce the API 's CCA such that the UE will re-associate itself with the neighboring API, where the interference level for the neighboring API is assumed to be smaller than the previous AP2. Furthermore, it is for user disconnects and reconnects to APs, not power control to increase S/N(signal-to-noise) .

In another embodiment, the central controller may be specifically used for beam selection with face to face beams in order to avoid transmitting two beams at the same time.

Figure 9 is a schematic diagram showing dynamic beam switching of access points. As shown in Figure 9, there are some APs, each AP has multiple beam antenna, for example, one of the APs has Bll, B12...B16. The central controller may select beam to reduce interference.

In another embodiment, the central controller may be specifically used to synchronize the micro base stations using the timing signal of the macro base station.

In an implement, APs can be timely synchronized by the macro base station timing, such that it is optionally and controlled by the central control board to synchronize some of the AP's transmission time. By enable some APs to transmit while disable other APs to transmit, it is possible to allow a terminal to hear one AP's signal without interfered by others. Figure 10 is a schematic diagram showing time synchronization of access points. As shown in Figure 10, in each time interval, a central controller needs to make sure overlapped beams has only one beam active at a time.

In this embodiment, since only one beam per AP is active at one time, so

AP can be picked that their head to head beams (beams face each other directly) do not active at the same time (either Tx or Rx). So this is the benefit of time synchronization. This will require APs report back at any time, which beam it is going to transmit/receive next so that the central controller can feedback to AP to let it know if it is a good choice or not.

Furthermore, a better way may be to define a pattern for each AP such that their adjacent beams never active at the same time. So it only needs synchronization timing, but not controls them every time.

In another embodiment, the central controller is specifically used to improve the overall network capacity by intelligent frequency allocation across the micro base stations, or load balancing of user affiliations across the micro base stations, or adaptive power controlling for the micro base stations.

In the present application, in one embodiment, each AP starts about 50% of its total Tx power, so a group of APs are overlap each other to form a tightly covered hotspot. It is assume that each AP's Tx power can be reduced to zero or to its maximum such at it can cover the other AP's area when it is set to the max power. Since each AP (assume single radio per AP) can have only one user transmition in time division duplex mode, although there are multiple beams on each AP, only one beam has signal to a specific direction.

In the present application, simplify the connection (from mesh connection to star connections) of small cell base stations WiFi APs by connecting them via a local central control point through cabled or wirelessly.

Such that the local central control point would work as small cell base station controller locally, and to provide base station collaborations, resource management, interference and power coordination, and synchronizations. The end result is to increase overall system capacity, resource utilization efficiency, service quality, and end user experience.

In the present application, some technology utilization is enabled, such as multiple antenna beam forming and sector selection across multiple small cell base stations WiFi APs, interference mitigations/avoidance, Tx power collaboration, and timing slot synchronization.

It can be seen form the above embodiments that simplify the connection of small cell base stations by connecting micro base stations via a central controller; and the overall system performance and radio resource utilization have been improved.

Embodiment 2

Based on embodiment 1, this embodiments of the present invention provide a central controller, applied in a network system with local clusters, the central controller is connected to multiple micro base stations so that a local cluster is formed; This embodiment correspondes to the above embodiment 1 and the same content will not be described.

Figure 11 is a schematic diagram of the central controller of an embodiment of the present invention. As shown in Figure 11, the central controller 103 includes: a first receiving unit 1101, a controlling unit 1102 and a first sending unit 1103. Other parts of the central controller can refer to the existing technology and not be described in the present application.

Wherein, the first receiving unit 1101 is configured to receive a request message from a micro base station; the controlling unit 1102 is configured to provide base station collaboration, resource management, interference and power coordination, or synchronization based on the request message; the first sending unit 1103 is configured to send a response message to the micro base station.

In this embodiment, the central controller 103 is connected to multiple micro base stations in star or spoke topology.

In this embodiment, the central controller 103 may be a plug-in of a macro base station; or the central controller 103 may be an external unit of the macro base station. However, it is not limited thereto, and particular implement way may be determined as actually required.

In an implement way, the central controller 103 is specifically used to reconfigure user equipment from one micro base station to another micro base station. In another implement way, the central controller is used to adjust powers of the micro base stations; the user equipment is used to search the adjusted powers; and the user equipment disconnects from a micro base station and re-attaches another micro base station based on the adjusted powers.

In another implement way, the central controller is used for beam selection with face to face beams in order to avoid transmitting two beams at the same time.

In another implement way, the central controller is specifically used to synchronize the micro base stations using the timing signal of the macro base station.

In another implement way, the central controller is specifically used for improving the overall network capacity by intelligent frequency allocation across the micro base stations, or load balancing of user affiliations across the micro base stations, or adaptive power controlling for the micro base stations.

It can be seen form the above embodiments that simplify the connection of small cell base stations by connecting micro base stations via a central controller; and the overall system performance and radio resource utilization have been improved. Embodiment 3

Based on embodiment 1 , this embodiments of the present invention provide a micro base station, applied in a network system with local clusters, the micro base station is collected to a central controller; the central controller is connected to multiple micro base stations so that a local cluster is formed; This embodiment correspondes to the above embodiment 1 and the same content will not be described.

Figure 12 is a schematic diagram of the micro base station of an embodiment of the present invention. As shown in Figure 12, the micro base stationl02 includes: a second sending unit 1201 and a second receiving unit 1202. Other parts of the micro base station 102 can refer to the existing technology and not be described in the present application.

Wherein, the second sending unit 1201 is configured to send a request message to the central controller; wherein the request message is used for requesting base station collaboration, resource management, interference and power coordination, or synchronization; the second receiving unit 1202 is configured to receive a response message from the central controller.

In this embodiment, the micro base station may be a pico base station, or a femto base station, or a WiFi acesss point. However, it is not limited thereto, and particular implement way may be determined as actually required.

This embodiments of the present invention further provide a macro base station, applied in a network system with local clusters, the macro base station is collected to one or more central controllers, each central controller is connected to multiple micro base stations so that a local cluster is formed;

Figure 13 is a schematic diagram of the macro base station of an embodiment of the present invention. As shown in Figure 13, the macro base station 101 includes: a third receiving unit 1301 and a third sending unit 1302. Other parts of the macro base station 101 can refer to the existing technology and not be described in the present application.

Wherein, the third receiving unit 1301 is configured to receive a request message from the central controller; the third sending unit 1302 is configured to send a response message to the central controller.

It can be seen form the above embodiments that simplify the connection of small cell base stations by connecting micro base stations via a central controller; and the overall system performance and radio resource utilization have been improved.lt should be understood that each of the parts of the present invention may be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods may be realized by software or firmware that is stored in the memory and executed by an appropriate instruction executing system. For example, if it is realized by hardware, it may be realized by any one of the following technologies known in the art or a combination thereof as in another embodiment: a discrete logic circuit having a logic gate circuit for realizing logic functions of data signals, application-specific integrated circuit having an appropriate combined logic gate circuit, a programmable gate array (PGA), and a field programmable gate array (FPGA), etc.

The description or blocks in the flowcharts or of any process or method in other manners may be understood as being indicative of comprising one or more modules, segments or parts for realizing the codes of executable instructions of the steps in specific logic functions or processes, and that the scope of the preferred embodiments of the present invention comprise other implementations, wherein the functions may be executed in manners different from those shown or discussed, including executing the functions according to the related functions in a substantially simultaneous manner or in a reverse order, which should be understood by those skilled in the art to which the present invention pertains.

The logic and/or steps shown in the flowcharts or described in other manners here may be, for example, understood as a sequencing list of executable instructions for realizing logic functions, which may be implemented in any computer readable medium, for use by an instruction executing system, device or apparatus (such as a system including a computer, a system including a processor, or other systems capable of extracting instructions from an instruction executing system, device or apparatus and executing the instructions), or for use in combination with the instruction executing system, device or apparatus.

The above literal description and drawings show various features of the present invention. It should be understood that those skilled in the art may prepare appropriate computer codes to carry out each of the steps and processes as described above and shown in the drawings. It should be also understood that all the terminals, computers, servers, and networks may be any type, and the computer codes may be prepared according to the disclosure to carry out the present invention by using the apparatus.

Particular embodiments of the present invention have been disclosed herein. Those skilled in the art will readily recognize that the present invention is applicable in other environments. In practice, there exist many embodiments and implementations. The appended claims are by no means intended to limit the scope of the present invention to the above particular embodiments. Furthermore, any reference to "a device to..." is an explanation of device plus function for describing elements and claims, and it is not desired that any element using no reference to "a device to..." is understood as an element of device plus function, even though the wording of "device" is included in that claim.

Although a particular preferred embodiment or embodiments have been shown and the present invention has been described, it is obvious that equivalent modifications and variants are conceivable to those skilled in the art in reading and understanding the description and drawings. Especially for various functions executed by the above elements (portions, assemblies, apparatus, and compositions, etc.), except otherwise specified, it is desirable that the terms (including the reference to "device") describing these elements correspond to any element executing particular functions of these elements (i.e. functional equivalents), even though the element is different from that executing the function of an exemplary embodiment or embodiments illustrated in the present invention with respect to structure. Furthermore, although the a particular feature of the present invention is described with respect to only one or more of the illustrated embodiments, such a feature may be combined with one or more other features of other embodiments as desired and in consideration of advantageous aspects of any given or particular application.

Claims

1. A network system with local cluster, the network system comprises a macro base station (101) and a plurality of micro base stations (102); the network system further comprising:

one or more central controllers (103), configured to provide base station collaboration, resource management, interference and power coordination, or synchronization for the plurality of micro base stations;

wherein the one or more central controllers (103) are connected to the macro base station (101); and each central controller is connected to multiple micro base stations (102) so that the local cluster is formed.

2. The network system according to claim 1, wherein the central controller (103) is connected to multiple micro base stations (103) in a star topology or a spoke topology.

3. The network system according to claim 1 or 2, wherein the micro base station (103) is a pico base station, or a femto base station, or a WiFi acesss point.

4. The network system according to any of claims 1-3, wherein the central controller (103) is a plug-in of the macro base station; or the central controller (103) is an external unit of the macro base station.

5. The network system according to any of claims 1-4, wherein the central controller (103) is specifically used to reconfigure an user equipment from one micro base station to another micro base station.

6. The network system according to claim 5, wherein the central controller (103) is used to adjust powers of the micro base stations (102); the user equipment is used to search the adjusted powers;

and the user equipment is disconnected from a micro base station and re-attaches another micro base station based on the adjusted powers.

7. The network system according to any of claims 1-4, wherein the central controller (103) is used for beam selection with face to face beams in order to avoid transmitting two beams at the same time.

8. The network system according to any of claims 1-4, wherein the central controller (103) is specifically used to synchronize the micro base stations (102) using a timing signal of the macro base station.

9. The network system according to claim 8, wherein only a beam of the synchronized micro base stations is active at a time.

10. The network system according to any of claims 1-4, wherein the central controller (103) is specifically used for improving the overall network capacity by intelligent frequency allocation across the micro base stations, or load balancing of user affiliations across the micro base stations, or adaptive power controlling for the micro base stations.

11. The network system according to any of claims 1-4, wherein the connection between the central controller (103) and the micro base stations

(102) is cabled, or wireless or both of them.

12. The network system according to any of claims 1-4, wherein the network system is applied in Universal Mobile Telecommunications System (UMTS), and the central controller is further connected to an Access Gateway (AG).

13. The network system according to any of claims 1-4, wherein the central controller (103) is further connected to a Mobility Management Entity (MME) and a serving Gateway (S-GW).

14. A central controller (103), applied in a network system with local cluster, the central controller (103) is connected to multiple micro base stations so that a local cluster is formed; the central controller (103) comprising:

a first receiving unit (1101), configured to receive a request message from one of the multiple micro base station;

a controlling unit (1102), configured to provide base station collaboration, resource management, interference and power coordination, or synchronization based on the request message;

a first sending unit (1103), configured to send a response message to the micro base station.

15. The central controller (103) according to claim 14, wherein the central controller (103) is connected to multiple micro base stations in star or spoke topology.

16. The central controller (103) according to claim 14 or 15, wherein the central controller (103) is a plug-in of a macro base station; or the central controller (103) is an external unit of the macro base station.

17. The central controller (103) according to any of claims 14-16, wherein the central controller (103) is specifically used to reconfigure user equipment from one micro base station to another micro base station.

18. The central controller (103) according to claim 17, wherein the central controller (103) is used to adjust powers of the micro base stations; the user equipment is used to search the adjusted powers;

19. The central controller (103) according to any of claims 14-16, wherein the central controller (103) is used for beam selection with face to face beams in order to avoid transmitting two beams at the same time.

20. The central controller (103) according to any of claims 14-16, wherein the central controller (103) is specifically used to synchronize the micro base stations using the timing signal of the macro base station.

21. The central controller (103) according to any of claims 14-16, wherein the central controller (103) is specifically used for improving the overall network capacity by intelligent frequency allocation across the micro base stations, or load balancing of user affiliations across the micro base stations, or adaptive power controlling for the micro base stations.

22. A micro base station (102), applied in a network system with local cluster, the micro base station (102) is collected to a central controller (103); the micro base station (102) comprising:

a second sending unit (1201), configured to send a request message to the central controller; wherein the request message is used for requesting base station collaboration, resource management, interference and power coordination, or synchronization;

a second receiving unit (1202), configured to receive a response message from the central controller.

23. The micro base station (102) according to claim 22, wherein the micro base station (102) is a pico base station, or a femto base station, or a WiFi acesss point.

24. A macro base station (101), applied in a network system with local cluster, the macro base station (101) is collected to one or more central controllers (103), the central controller (103) is connected to multiple micro base stations (102) so that the local cluster is formed;

the macro base station (101) comprising:

a third receiving unit (1301), configured to receive a request message from the central controller.

a third sending unit (1302), configured to send a response message to the central controller.