Patent ID: 12238536

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present exemplary embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

FIG.1is a schematic diagram of an electronic device100for configuring radio units in a hierarchical network according to one embodiment of the disclosure. The electronic device100may include a processor110, a storage medium120, and a transceiver130. The processor110is coupled to the storage medium120and the transceiver140and is configured to access and execute a plurality of modules stored in the storage medium120. In one embodiment, the electronic device may be a base station such as gNB.

The processor110could be implemented by using programmable units such as a micro-processor, a micro-controller, a DSP chip, a field programmable gate array (FPGA), and so forth. The functions of the processor110may also implemented with separated electronic devices or ICs.

The storage medium120may be, for example, any type of fixed or removable random access memory (RAM), a read-only memory (ROM), a flash memory, a hard disk drive (HDD), a solid state drive (SSD) or similar element, or a combination thereof, configured to record a plurality of modules or various applications executable by the processor110, wherein the plurality of modules may include a module121, a module122, and a module123. The module121may be used for collecting traffic data of the radio access network. The module122may be used for managing power or antenna parameters, deploying the location for the radio unit, distributing the operating frequency and bandwidth for the radio unit, or managing the power saving mode for the radio unit. The module123may be used for analyzing the traffic data of a UE in the radio access network or adjusting handover parameters for the radio unit. The functions of the module121, module122, and module123will be described in detail later.

The transceiver130may be configured to transmit or receive signals. The transceiver130may also perform operations such as low noise amplifying, impedance matching, frequency mixing, up or down frequency conversion, filtering, amplifying, and so forth. The transceiver130may include one or more digital-to-analog (D/A) converters or analog-to-digital (A/D) converters which are configured to convert from an analog signal format to a digital signal format during uplink signal processing and from a digital signal format to an analog signal format during downlink signal processing. The electronic device100may communicate with radio units in the hierarchical network via the transceiver130.

FIG.2is a flowchart of a method for configuring radio units in a hierarchical network according to one embodiment of the disclosure, wherein the method can be implemented by the electronic device100as shown inFIG.1.

In step S201, the module121may obtain information of a plurality of radio units from the hierarchical network via the transceiver130. The information may at least include locations or coverages of the plurality of radio units, but the present disclosure is not limited thereto. For example, as shown inFIG.3A, the module121may obtain locations or coverages of radio unit31,32,33, and34.

In step S202, the module122may determine a radio unit type for each of the plurality of radio units, wherein the radio unit type may include a coverage radio unit, a capacity radio unit, or a normal radio unit. A coverage radio unit may provide a basic signal coverage continuously, wherein the bandwidth allocated to the coverage radio unit may be narrower such that the bandwidth resources can be saved. During the non-peak hours, a capacity radio unit may be turned off to save power. When the traffic of a coverage radio unit is too high, the capacity radio unit corresponding to the coverage radio may be turned on to offload the traffic for the coverage radio unit. Some UE served by the coverage radio units may handover to the corresponding capacity radio unit. If a radio unit is not selected as a coverage radio unit or a capacity radio unit, the radio unit may be classified as a normal radio unit. The normal radio unit may operate in a conventional manner, as specified in 3GPP specifications.

In the following embodiments, it is assumed that the plurality of radio units may include at least a first coverage radio unit (e.g., radio unit32), a second coverage radio unit (e.g., radio unit33), and a first capacity radio unit (e.g., radio unit35) belonging to the first coverage radio unit. Furthermore, it is assumed that the information obtained by the module122may include at least a coverage of the second coverage radio unit and a coverage of the first capacity radio unit.

In one embodiment, the bandwidth of the second coverage radio unit is a bandwidth farthest from the bandwidth of the first coverage radio unit in a default bandwidth. For example, assuming that the default bandwidth is between 4800 MHZ to 4900 MHz. If the operating bandwidth of the first coverage radio unit (e.g., radio unit32) includes 4800 MHZ, the operating bandwidth of the second coverage radio (e.g., radio unit33) unit may include 4900 MHz such that the operating bandwidth of the second coverage radio unit is the bandwidth farthest from the bandwidth of the first coverage radio unit in the default bandwidth 4800 MHz to 4900 MHz.

In one embodiment, assuming that the plurality of radio units includes a first radio unit and a second radio unit, the module122may select the first radio unit from the plurality of radio units as the first coverage radio unit according to a reference distance of the first radio unit. Specifically, the module122may set a distance between the first radio unit and the second radio unit as the reference distance of the first radio unit in response to the second radio unit being a radio unit nearest to the first radio unit within the coverage of the first radio unit. For multiple radio units in a specific coverage (e.g., a coverage of one of the multiple radio units), the module122may select the first radio unit from the multiple radio units as the first coverage radio unit in response to the reference distance of the first radio unit being the smallest reference distance.

For example, as shown inFIG.5A, assuming that radio units51,55, and56are located within the coverage of each other. The module122may set the distance between the radio unit51and the radio unit56as the reference distance of the radio unit51in response to the radio unit56being a radio unit nearest to the radio unit51within the coverage of the radio unit51. In similar manner, the module122may obtain information as represented in Table 1. For specific coverage (e.g., coverage of radio units51,55, or56), the module122may select radio unit51(or radio unit56) as the coverage radio unit for the specific coverage if distance “A” is less than distance “B” (i.e., distance “A” is the smallest reference distance in Table 1).

TABLE 1radio unitreference distance for the radio unit51distance between radio units 51 and 56 (also referredto as distance “A”)55distance between radio units 55 and 51 (also referredto as distance “B”)56distance between radio units 51 and 56 (also referredto as distance “A”)

In one embodiment, assuming that the plurality of radio units includes a first radio unit and a second radio unit, the module122may select the first radio unit from the plurality of radio units as the first coverage radio unit according to a reference distance of the first radio unit. Specifically, the module122may set a distance between the first radio unit and the second radio unit as the reference distance of the first radio unit in response to the second radio unit being a radio unit farthest from the first radio unit within the coverage of the first radio unit. For multiple radio units in a specific coverage (e.g., a coverage of one of the multiple radio units), the module122may select the first radio unit from the multiple radio units as the first coverage radio unit in response to the reference distance of the first radio unit being the largest reference distance.

For example, as shown inFIG.7A, assuming that radio units71,74, and76are located within the coverage of each other. The module122may set the distance between the radio unit71and the radio unit74as the reference distance of the radio unit71in response to the radio unit74being a radio unit nearest to the radio unit71within the coverage of the radio unit71. In similar manner, the module122may obtain information as represented in Table 2. For specific coverage (e.g., coverage of radio units71,74, or76), the module122may select radio unit71(or radio unit74) as the coverage radio unit for the specific coverage if distance “C” is greater than distance “D” (i.e., distance “C” is the largest reference distance in Table 2).

TABLE 2radio unitreference distance for the radio unit71distance between radio units 71 and 74 (also referredto as distance “C”)74distance between radio units 71 and 74 (also referredto as distance “C”)76distance between radio units 74 and 76 (also referredto as distance “D”)

After determining the first coverage radio unit for a specific coverage, the module122may select a second radio unit from the plurality of radio units as the first capacity radio unit belonging to the first coverage radio unit in response to the second radio unit being in the coverage of the first coverage radio unit. For example, as shown inFIG.7A, after determining the radio unit71as the coverage radio unit, the module122may select the radio units74and76as the capacity radio units belonging to the radio unit71in response to the radio units74and76being in the coverage of the radio unit71.

In step S203, the module122may turn on the first coverage radio unit (or the second coverage radio unit). Specifically, the module122may configured the first coverage radio unit (or the second coverage radio unit) to start performing registration process to the core network and providing network service for the UE within the coverage of the first coverage radio unit (or the second coverage radio unit). In one embodiment, the module122may configure the bandwidth of the second coverage radio unit such that the bandwidth of the second coverage radio unit may not overlapped with the bandwidth of the first coverage radio unit. For example, as shown inFIG.3B, assuming that the radio unit32is the first coverage radio unit and the radio unit33is the second coverage radio unit. The module122may configure the bandwidth of the radio unit33such that the bandwidth of the radio unit33(i.e., 4890-4900 MHZ) may not overlapped with the bandwidth of the radio unit32(i.e., 4800-4810 MHz).

In one embodiment, the module122may configure the coverage radio unit to perform data transmission for both the control plane and the user plane of the hierarchical network.

In step S204, the module121may monitor the service state for each of the radio units and obtain information from each of the radio units. For example, the module121may obtain information such as traffic of the first coverage radio unit (e.g., radio unit32), traffic of the second coverage radio unit (e.g., radio unit33), or traffic of the first capacity radio unit (e.g., radio unit35).

In step S205, the module123may determine whether the traffic of the first capacity radio unit is less or equal to a threshold. If the traffic of the first capacity radio unit is less than or equal to the threshold for a pre-configured time period, proceed to step S208. If the traffic of the first capacity radio unit is greater than the threshold after the preconfigured time period, proceed to step S206.

In step S206, the module122may determine whether the bandwidth or coverage of the first capacity radio unit is overlapped with the bandwidth or coverage of the second coverage radio unit. If the bandwidth of the first capacity radio unit is overlapped with the bandwidth of the second coverage radio unit and the coverage of the first capacity radio unit is overlapped with the coverage of the second coverage radio unit, proceed to step S207. If the bandwidth of the first capacity radio unit may not overlapped with the bandwidth of the second coverage radio unit or the coverage of the first capacity radio unit may not overlapped with the coverage of the second coverage radio unit, proceed to step S204.

In step S207, the module122may configured the first capacity radio unit via the transceiver130. Specifically, the module122may reduce a power (e.g., transmission power) of the first capacity radio unit such that the second coverage radio unit would not be interfered by the first capacity radio unit.

In step S208, the module122may turn off the first capacity radio unit via the transceiver130so as to save power.

In step S209, the module123may determine whether the traffic of the first coverage radio unit is greater than a threshold. If the traffic of the first coverage radio unit is greater than the threshold, proceed to step S210. If the traffic of the first coverage radio unit is less than or equal to the threshold, proceed to step S204.

In step S210, the module122may determine whether the first capacity radio unit belonging to the first coverage radio unit is turned off. If the first capacity radio unit is turned off, proceed to step S211, If the first capacity radio unit is turned on, proceed to step S212.

In step S211, the module122may turn on the first capacity radio unit via the transceiver130. Specifically, the module122may configure the bandwidth of the first capacity radio unit such that the bandwidth of the first capacity radio unit may not overlapped with the bandwidth of the first coverage radio unit. In one embodiment, the first capacity radio unit may support operation in a single bandwidth. That is, the first capacity radio unit cannot operate in two or more bandwidths in the same time.

In step S212, the module123may configure a UE to handover from the first coverage radio unit to the first capacity radio unit via the transceiver130. In one embodiment, the module122may configure a beamforming parameter for the first capacity radio unit after the first capacity radio unit is turned on.

In one embodiment, the module122may configured the first capacity radio unit to perform data transmission for the control plane and the user plane of the hierarchical network.

FIG.3Ais a schematic diagram of coverages of coverage radio units according to one embodiment of the disclosure.FIG.3Bis an amplitude-frequency plot of the coverage radio units inFIG.3Aaccording to one embodiment of the disclosure. Referring toFIGS.3A and3B. it is assumed that radio units31,32,33, and34are coverage radio units, the radio unit35is a capacity radio unit belonging to the radio unit32, and the radio unit36is a capacity radio unit belonging to the radio unit34. The radio unit32and the radio unit35belonging to the radio unit32may be located in the same position, and the radio unit34and the radio unit36belonging to the radio unit34may be located in the same position.

Assuming that the bandwidth of the radio unit32is configured to 4800-4810 MHz by the module122. To configure the radio unit33whose coverage is overlapped with the radio unit32, the module122may configure the bandwidth of radio unit33to 4890-4900 MHz such that the bandwidth of the radio unit33may not overlapped with the bandwidth of the radio unit32. Furthermore, the module122may configure the bandwidth of the radio unit33to 4890-4900 MHz such that the bandwidth of the radio unit33may be a bandwidth farthest from the bandwidth (i.e., 4800-4810 MHz) of the radio unit32in the default bandwidth 4800-4900 MHz as shown inFIG.3B. It should be noted that, the bandwidth of the radio unit31can be overlapped with the bandwidth of the radio unit34since the coverages of the radio units31and34are not overlapped with each other.

FIG.4Ais a schematic diagram of coverages of capacity radio units according to one embodiment of the disclosure.FIG.4Bis an amplitude-frequency plot of the capacity radio units inFIG.4Aaccording to one embodiment of the disclosure. Referring toFIGS.4A and4B, it is assumed that the radio units31,32,33, and34are coverage radio units, the radio unit35is a capacity radio unit belonging to the radio unit32, and the radio unit36is a capacity radio unit belonging to the radio unit34. The radio unit32and the radio unit35belonging to the radio unit32may be located in the same position, and the radio unit34and the radio unit36belonging to the radio unit34may be located in the same position, wherein the coverage of the radio unit35may be smaller than the coverage of the radio unit32, and the coverage of the radio unit36may be smaller than the coverage of the radio unit34.

Taking the radio units32and35as an example, if the traffic of the radio unit32is greater than a threshold, the module122may turn on the radio unit35. The module123may configure the UE served by the radio unit32to handover from the radio unit32to radio unit35so as to offload the traffic for the radio unit32. The module122may configure the bandwidth of the radio unit35to 4830-4890 MHz such that the bandwidth of the radio unit35may not overlapped with the bandwidth (i.e., 4800-4810 MHz) of the radio unit32.

Since the coverage of the radio unit35is overlapped with the coverage of the radio unit33and the bandwidth of the radio unit35is overlapped with the bandwidth (i.e., 4890-4900 MHZ) of the radio unit33, the module122may reduce the power of the radio unit35such that the interference of the radio unit35to the radio unit33can be reduced. If the traffic of the radio unit35is less than a threshold for a pre-configured time period, the module122may turn off the radio unit35to save power.

FIG.5Ais a schematic diagram of coverages of coverage radio units according to one embodiment of the disclosure.FIG.5Bis an amplitude-frequency plot of the coverage radio units inFIG.5Aaccording to one embodiment of the disclosure. Referring toFIGS.5A and5B, the module121may obtain information including locations and coverages of the radio units51,52,53,54,55,56,57, and58. The module122may determine a radio unit type for each of the radio units. Taking radio unit51as an example, the module122may select the radio unit51from the plurality of radio units as a coverage radio unit according to a reference distance of the radio unit51. In one embodiment, the module122may set a distance between the radio unit51and radio unit56as the reference distance of the radio unit51in response to the radio unit56being a radio unit nearest to the radio unit51within the coverage of the radio unit51. Accordingly, the module122may obtain information as represented in Table 1. The module122may select the radio unit51as a coverage radio unit according to Table 1. In similar manner, the module122may further select the radio units52,53, and54as coverage radio units.

After the coverage radio units are determined, the module122may select the radio units55and56as the capacity radio units belonging to the radio unit51in response to the radio units55and56being in the coverage of the radio unit51. In similar manner, the module122may select the radio unit57as the capacity radio unit belonging to the radio unit52, and may select the radio unit58as the capacity radio unit belonging to the radio unit53, wherein the coverage of the radio unit57may be smaller than the coverage of the radio unit52, and the coverage of the radio unit58may be smaller than the coverage of the radio unit53.

If a specific radio unit is not located in any coverage of the radio units, and no radio unit is located in a coverage of the specific radio unit, the module122may select the specific radio unit as a normal radio unit. For example, since the radio unit54is not located in any coverage of the radio units and no radio unit is located in the coverage of the radio unit54, the module122may select the radio unit54as a normal radio unit.

After the radio unit type for each radio unit being determined, the module122may configure each coverage radio unit. Assuming that the bandwidth of the radio unit51is configured to 4800-4810 MHz by the module122. To configure the radio unit52whose coverage is overlapped with the radio unit51, the module122may configure the bandwidth of the radio unit52to 4890-4900 MHz such that the bandwidth of the radio unit52may not overlapped with the bandwidth of the radio unit51. Furthermore, the module122may configure the bandwidth of the radio unit52to 4890-4900 MHz such that the bandwidth of the radio unit52may be a bandwidth farthest from the bandwidth (i.e., 4800-4810 MHz) of the radio unit51in the default bandwidth 4800-4900 MHz as shown inFIG.5B.

FIG.6Ais a schematic diagram of coverages of capacity radio units according to one embodiment of the disclosure.FIGS.6B and6Care amplitude-frequency plots of the capacity radio units inFIG.6Aaccording to one embodiment of the disclosure. Referring toFIGS.6A,6B, and6C, it is assumed that the radio units51,52,53, and54are coverage radio units, the radio units55and56are capacity radio units belonging to the radio unit51, the radio unit57is the capacity radio unit belonging to the radio unit52, the radio unit58is a capacity radio unit belonging to the radio unit53, and the radio unit54is a normal radio unit, wherein the coverage of the radio unit55or radio unit56may be smaller than the coverage of the radio unit51, the coverage of the radio unit57may be smaller than the coverage of the radio unit52, and the coverage of the radio unit58may be smaller than the coverage of the radio unit53.

Taking the radio units51,55, and56as an example, if the traffic of the radio unit51is greater than a threshold, the module122may turn on the radio unit55or radio unit56. The module123may configure the UE served by the radio unit51to handover from the radio unit51to the radio unit55or radio unit56so as to offload the traffic for the radio unit51. The module122may configure the bandwidth of the radio unit56(or radio unit55) to 4820-4900 MHz such that the bandwidth of the radio unit56may not overlapped with the bandwidth (i.e., 4800-4810 MHz) of the radio unit51. Taking the radio units52and57as another example, if the traffic of the radio unit52is greater than a threshold, the module122may turn on the radio unit57. The module123may configure the UE served by the radio unit52to handover from the radio unit52to the radio unit57so as to offload the traffic for the radio unit52. The module122may configure the bandwidth of the radio unit57to 4800-4880 MHz such that the bandwidth of the radio unit57may not overlapped with the bandwidth (i.e., 4890-4900 MHz) of the radio unit52.

Since the coverage of the radio unit56is overlapped with the coverage of the radio unit52and the bandwidth (i.e., 4820-4900 MHZ) of the radio unit56is overlapped with the bandwidth (i.e., 4890-4900 MHZ) of the radio unit52, the module122may reduce the power of the radio unit56such that the interference of the radio unit56to the radio unit52can be reduced. If the traffic of the radio unit56is less than a threshold for a pre-configured time period, the module122may turn off the radio unit56to save power.

FIG.7Ais a schematic diagram of coverages of coverage radio units according to one embodiment of the disclosure.FIG.7Bis an amplitude-frequency plot of the coverage radio units inFIG.7Aaccording to one embodiment of the disclosure. Referring toFIGS.5A and5B, the module121may obtain information including locations and coverages of the radio units71,72,73,74,75, and76. The module122may determine a radio unit type for each of the radio units. Taking radio unit71as an example, the module122may select the radio unit71from the plurality of radio units as a coverage radio unit according to a reference distance of the radio unit71. In one embodiment, the module122may set a distance between the radio unit71and radio unit74as the reference distance of the radio unit71in response to the radio unit74being a radio unit farthest from the radio unit71within the coverage of the radio unit71. Accordingly, the module may obtain information as represented in Table 2. The module122may select the radio unit71as a coverage radio unit according to Table 2. In similar manner, the module122may further select the radio units72and73as coverage radio units.

After the coverage radio units are determined, the module122may select the radio units74and76as the capacity radio units belonging to the radio unit71in response to the radio units74and76being in the coverage of the radio unit71. In similar manner, the module122may select the radio unit75as the capacity radio unit belonging to the radio unit72.

If a specific radio unit is not located in any coverage of the radio units, and no radio unit is located in a coverage of the specific radio unit, the module122may select the specific radio unit as a normal radio unit. For example, since the radio unit73is not located in any coverage of the radio units and no radio unit is located in the coverage of the radio unit73, the module122may select the radio unit73as a normal radio unit.

After the radio unit type for each radio unit being determined, the module122may configure each coverage radio unit. Assuming that the bandwidth of the radio unit71is configured to 4800-4810 MHz by the module122. To configure the radio unit72whose coverage is overlapped with the radio unit71, the module122may configure the bandwidth of the radio unit72to 4890-4900 MHz such that the bandwidth of the radio unit72may not overlapped with the bandwidth of the radio unit71. Furthermore, the module122may configure the bandwidth of the radio unit72to 4890-4900 MHz such that the bandwidth of the radio unit72may be a bandwidth farthest from the bandwidth (i.e., 4800-4810 MHz) of the radio unit71in the default bandwidth 4800-4900 MHz as shown inFIG.7B.

FIG.8Ais a schematic diagram of coverages of capacity radio units according to one embodiment of the disclosure.FIG.8Bis an amplitude-frequency plot of the capacity radio units inFIG.8Aaccording to one embodiment of the disclosure. Referring toFIGS.8A and8B, it is assumed that the radio units71,72, and73are coverage radio units, the radio units74and76are capacity radio units belonging to the radio unit71, the radio unit75is a capacity radio unit belonging to the radio unit72, and the radio unit73is a normal radio unit.

Taking the radio units71and74as an example, if the traffic of the radio unit71is greater than a threshold, the module122may turn on the radio unit74. The module123may configure the UE served by the radio unit71to handover from the radio unit71to the radio unit74so as to offload the traffic for the radio unit71. The module122may configure the bandwidth of the radio unit74to 4820-4900 MHz such that the bandwidth of the radio unit74may not overlapped with the bandwidth (i.e., 4800-4810 MHz) of the radio unit71. In one embodiment, the module122may configure a beamforming parameter for the radio unit74via the transceiver130in response to the radio unit74being turned on.

Since the coverage of the radio unit74is overlapped with the coverage of the radio unit73and the bandwidth (i.e., 4820-4900 MHZ) of the radio unit74is overlapped with the bandwidth (i.e., 4840-4880 MHz) of the radio unit73, the module122may reduce the power of the radio unit74such that the interference of the radio unit74to the radio unit73can be reduced. If the traffic of the radio unit74is less than a threshold for a pre-configured time period, the module122may turn off the radio unit74to save power.

FIG.9is a schematic diagram of an open radio access network (O-RAN) architecture according to one embodiment of the disclosure, wherein the O-RAN architecture may include a service management and orchestration (SMO) component, near-real-time RAN intelligent controllers (RIC), a central unit (CU) in the gNB, one or more distributed units (DU) in the gNB, and one or more radio units (RU). In one embodiment, the module122may be implemented in the near-real-time RIC in the SMO component, and the modules121and123may be implemented in the near-real-time RIC coupled between the SMO component and the gNB. The detail information of the O-RAN architecture can be represented by Table 3.

TABLE 3messagemodulefunctioninterfacetargetprotocolformat122networkO1CU, DU,Netconf/O1-interfacetopologyRURESTdata modelsmanagementbandwidthO1allocationswitching ofO1power savingmode121collection ofE2CU, DUE2APE2SM-RC:traffic dataE2 report,from RANE2SM-KPMA1Non-real-A1APA1TDtime RIC123UE trafficE2CU, DUE2APE2SM-RC:analysis;E2 report,handoverE2 controlparameterconfiguration

FIG.10is a flowchart of a method for configuring radio units in a hierarchical network according to one embodiment of the disclosure, wherein the method can be implemented by the electronic device100as shown inFIG.1. In step S101, obtaining information of a plurality of radio units from the hierarchical network, wherein the plurality of radio units comprising a first coverage radio unit, a second coverage radio unit, and a first capacity radio unit belonging to the first coverage radio unit, wherein the information comprising a coverage of the second coverage radio unit and a coverage of the first capacity radio unit. In step S102, configuring a bandwidth of the second coverage radio unit such that the bandwidth of the second coverage radio unit is not overlapped with a bandwidth of the first coverage radio unit. In step S103, configuring a bandwidth of the first capacity radio unit such that the bandwidth of the first capacity radio unit is not overlapped with the bandwidth of the first coverage radio unit. In step S104, reducing a power of the first capacity radio unit in response to the coverage of the first capacity radio unit being overlapped with the coverage of the second coverage radio unit and the bandwidth of the first capacity radio unit being overlapped with the bandwidth of the second coverage radio unit.

In view of the aforementioned description, the electronic device in the present invention may determine a type for each of the radio units in a field according to the coverages of the radio units or the distances among the radio units, wherein different types of radio units may operate in different ways. When the network traffic is low, the electronic device may configure only a few coverage radio units to serve the whole field. On the other hand, when the network traffic is high, the electronic device may turn on a capacity radio unit for the coverage radio unit to offload the network traffic for the coverage radio unit. The electronic device may configure the power or beamforming parameter of a capacity radio unit if the operating bandwidth or the coverage of the capacity radio unit interferes a coverage radio unit. Accordingly, the disclosure provides a power saving mechanism for the hierarchical network which can guarantee the signal coverage and QoS of the network regardless the capacity radio unit is turned on or turned off.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.