CN104469817A - Method for controlling small base station dormancy based on load and interference level - Google Patents

Abstract

The invention provides a method for controlling a small cell to hibernate based on a load and an interference level. The method comprises the following steps: judging the load capacity of a current cell, and starting a process for judging whether the presence of the small cell brings a certain degree of downlink interference on peripheral neighboring cells or not when the load capacity reaches a certain level and a small cell user is positioned on the edge of the cell; and if the small cell brings a certain degree of interference on the peripheral neighboring cells, allowing the small cell to enter a hibernation state, and switching a home user of the small cell to an appropriate cell. According to the method for controlling the small cell to hibernate based on the load and the interference level, the small cell in a hierarchical networking scene is controlled to enter the hibernation state through adjustment of the service load of the cell and the generated interference level, so that inference in the hierarchical networking scene, particularly the downlink interference caused by a reference signal and the like is effectively lowered; the system throughput is increased; effective running of the system is ensured; energy consumption is saved; and green communication is realized.

Description

Method for controlling small base station dormancy based on load and interference level

technical field

The present invention belongs to the technical field of the fourth generation mobile communication network, and in particular relates to a method for controlling dormancy of a small base station based on load and interference level.

Background technique

Currently 3GPP R12 is conducting research on "Small Cell Enhancements (SCE) for E-UTRA and E-UTRAN–Physical-layer Aspects" (E-UTRA network small cell physical layer enhancement). Among them, for the effective operation of the small base station, an effective interference coordination mechanism is proposed for changing services in the physical layer, and attention is paid to the dynamic dormancy and activation of the small base station. Wherein, the sleep state refers to turning off the downlink channel transmission of the base station, and not sending any reference signal (Reference Signal, RS).

In R12, in order to improve the system throughput, small base stations will be densely deployed in the coverage area of the high-traffic macro base station to balance the load of the macro base station. However, the dense deployment of small base stations will bring more interference and make the interference environment more complex. The main source of interference will not be one, but multiple, and it is not only macro base stations that will cause downlink interference. Strong downlink interference will also be generated. Therefore, in order to reduce or eliminate interference, the small base station can be turned off when there are no users, so that it enters a dormant state; and when the user enters the coverage of the small base station, the small base station is activated to avoid coverage holes. This can not only reduce interference, but also save energy consumption and realize green communication.

At present, the dormancy of small base stations in hierarchical networking is mainly dynamically adjusted according to service modes or service traffic. For example, when the business traffic is heavy during the day, all the base stations are turned on, and when the business traffic decreases at night, some base stations are turned off. In the 3GPP standardization meeting, for the layered networking of densely deployed small base stations, it was proposed that when the traffic volume decreases, small base stations can be turned off to reduce interference and make the network operate effectively. However, specific options were not discussed further.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for controlling the dormancy of small base stations based on load and interference level, which aims at the hierarchical network scenario where small base stations are densely deployed, from both the load of the cell and the interference level. Considering from this dimension, when there are few users belonging to the small base station, and its existence causes various interferences, especially the interference caused by the downlink reference signal of the small base station, the small base station is put into a dormant state, so as to reduce interference and save energy. Consumption and improve the efficiency of network operation.

In order to achieve the above purpose and other related purposes, the present invention provides a method for controlling dormancy of a small base station based on load and interference level, which at least includes the following steps:

Step S1: Small base stations exchange cell load level information, and the small base station continuously detects the load of the cell;

Step S2: When the small base station detects that the load level of the cell is moderate load and full load, the small base station continues to detect the load of the cell; when the small base station detects that the load level of the cell is ultra-light load, determine that the small base station enters sleep mode state, go to step S8; when the small base station detects that the load level of the cell is light load, go to step S3;

Step S3: Judging whether any user among the home users of the small base station is located at the edge of the cell; if no user is located at the edge of the cell, the small base station enters the power adjustment process and proceeds to step S4; if there is a user located at the edge of the cell, the small base station starts the dormancy process, Go to step S5;

Step S4: Reduce the transmit power of the small base station, and continuously monitor the cell load of the small base station. When a new user is detected and the load level remains unchanged, determine whether the user is at the edge of the cell. If the user is at the edge of the cell, increase The transmission power of the large base station is transferred to step S5. If the user is located in the center of the cell, the small base station remains the same; when a new user is detected and the load level changes, enter step S7;

Step S5: The small base station judges whether the level of interference caused by the cell to the neighboring cell is high or low according to the "inter-cell interference indication" information sent by the neighboring cell; if the interference level is low, exit the sleep process and enter step S6; if it is high interference level, it is determined that the small base station enters a dormant state, and then proceeds to step S8;

Step S6: The small base station continuously detects the load of the cell. If a new user access is detected and the load level changes, go to step S7; if the load level continues to be light load, update the received "inter-cell interference indication" information , to determine the level of interference brought by the cell to the neighboring cells;

Step S7: If the small base station detects that the load level is moderate load or full load, the small base station continues to detect the load of the cell;

Step S8: Handover the users belonging to the small base station to the adjacent small base station or the macro base station, and the small base station enters a dormant state after the user handover is completed.

According to the above method for controlling dormancy of a small base station based on load and interference level, wherein: the cell load levels of the small base station include ultra-light load, light load, medium load and full load, and the small base station records the load level information of neighboring cells in the small base station In the automatic neighbor relationship of the base station.

According to the above-mentioned method for controlling the dormancy of the small base station based on load and interference level, wherein: in step S3, it is judged whether there is a user located at the edge of the cell by the following two methods:

A. Compare the RSRP information of this cell and the RSRP information of neighboring cells reported by the user, and judge whether the user is located at the edge of the cell by the difference between the two information;

B. Judging whether the user is located at the edge of the cell based on the user coordinate location information.

According to the above-mentioned method for controlling the dormancy of the small base station based on the load and the interference level, wherein: in step S5, the small base station judges whether the interference level caused by the own cell to the neighboring cell is high or low according to the "inter-cell interference indication" information sent by the neighboring cell Methods as below:

The adjacent cell sets an interference threshold, and the home user of the adjacent cell reports the detected RSRP of the small base station. If the RSRP of the small base station exceeds the interference threshold, when the adjacent cell sends the "Inter-cell Interference Indication" message, the corresponding PRB resource For identification, the small base station counts the number of PRBs exceeding the interference threshold after receiving the "Inter-cell Interference Indication" information; when the number of PRBs exceeding the interference threshold exceeds a certain percentage, it is considered a high interference level, otherwise it is considered a low interference level .

According to the above-mentioned method for controlling the dormancy of the small base station based on the load and the interference level, wherein: in step S5, the small base station judges whether the interference level caused by the own cell to the neighboring cell is high or low according to the "inter-cell interference indication" information sent by the neighboring cell Methods as below:

The adjacent cell compares the measured RSRP of the small base station reported by its home user with the set interference threshold, and counts the number of PRBs exceeding the interference threshold; if the number of PRBs exceeding the interference threshold exceeds a certain percentage, it is determined to be high interference Otherwise, it is determined as a low interference level, and the level of interference is marked in the "Inter-cell Interference Indication" information.

According to the above method for controlling the dormancy of the small base station based on the load and interference level, the updated "inter-cell interference indication" information will be resent to the small base station only when the "inter-cell interference indication" information of the neighboring cell changes. base station.

According to the above method of controlling the dormancy of the small base station based on the load and interference level, wherein: in step S8, the principle of selecting the handover base station for the home user is: preferentially select the small base station with a moderate load, and if there is no small base station that meets the requirements, switch to the macro base station.

As mentioned above, the method for controlling the dormancy of the small base station based on the load and the interference level of the present invention has the following beneficial effects:

(1) The present invention controls whether the small base station enters the sleep state in the layered networking scenario by judging the business load of the cell and the generated interference level, thereby effectively reducing the interference in the layered networking scenario, especially referring to The downlink interference caused by signals, etc. improves the system throughput, ensures the effective operation of the system, saves energy consumption, and realizes green communication;

(2) The present invention is applicable to the LTE-A network system, can be applied to a network composed of base stations with different powers, and can also be applied to a mixed network where other systems are covered by base stations with different powers.

Description of drawings

FIG. 1 is a schematic structural diagram of a layered network for dense deployment of small base stations in a coverage area of a high-traffic macro base station in a fourth-generation mobile communication system.

Fig. 2 is a schematic diagram of the structure of a certain small base station after dormancy in a layered network for densely deploying small base stations in the coverage area of a high-traffic macro base station in a fourth-generation mobile communication system;

Fig. 3 is a flow chart of the method for controlling the dormancy of the small base station based on the load and the interference level of the present invention.

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

It should be noted that the diagrams provided in this embodiment are only schematically illustrating the basic idea of the present invention, and only the components related to the present invention are shown in the diagrams rather than the number, shape and shape of the components in actual implementation. Dimensional drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

The present invention controls the dormancy of the small base stations based on the load, user location and interference level in the layered networking scenario where the small base stations are densely deployed in the coverage area of the macro base station. The small base station first judges the load of the cell. When the load reaches a certain level and the user of the small base station is located at the edge of the cell, it starts the process of judging whether the existence of the small base station will cause a certain degree of downlink interference to the surrounding adjacent cells; If the base station brings a certain degree of interference to the surrounding neighboring cells, the small base station enters a dormant state and switches its own users to a suitable base station.

Wherein, the load of the small base station is set to the following four levels: ultra-light load, light load, medium load and full load. The small base stations exchange load level information through the X2 interface, and record the exchanged load level information in the automatic neighbor relationship of the small base stations. When the load level of the adjacent cells of the small base station changes, the load level information in the automatic neighbor cell relationship of the small base station is updated. If the load of the small base station is ultra-light, it is determined that it enters a dormant state; if the load is light, it is determined whether there is a user in the small base station located at the edge of the cell. If there is a user at the edge of the cell, start the process of judging whether the small base station brings downlink interference to neighboring cells; if there is no user at the edge of the cell, adjust the small base station to an appropriate transmit power.

If it is determined that the small base station enters the dormant state, its home user preferentially selects a neighbor small base station with a moderate load for handover. If there is no small base station that meets the requirements, it will switch to the macro base station. After the user handover is completed, the small base station enters the dormant state.

FIG. 1 depicts a schematic structural diagram of a layered network for dense deployment of small base stations in a coverage area of a high-traffic macro base station in a fourth-generation mobile communication system. Among them, the layered network is based on the macro cellular network composed of macro base stations, plus multiple low-power small cells (small cells, sc) coverage, and small cells are densely deployed to form a multi-layer network covered by base stations with different power . As shown in Figure 2, after starting the control based on load and interference level, the small base station sc7 satisfies the requirements of entering the dormant state. UE3 switches to the neighboring small base station sc2, and the small base station sc7 enters a dormant state.

Referring to FIG. 3, the method for controlling the dormancy of the small base station based on the load and the interference level of the present invention specifically includes the following steps:

Step S1: The small base station continuously monitors the load of the cell, and the small base stations exchange cell load level information through the X2 interface and record the load level information of neighboring cells in the Automatic Neighbor Relationship (ANR) of the small base station, and This information is updated when the load level of neighboring cells changes.

Step S2: When the small base station detects that the load level of the cell is moderate load and full load, the small base station continues to detect the load of the cell; when the small base station detects that the load level of the cell is ultra-light load, determine that the small base station enters sleep mode state, go to step S8; when the small base station detects that the load level of the cell is light load, go to step S3.

Step S3: first judge the distribution of the home users of the small base station, and determine whether any user is located at the edge of the cell. Among them, the following two methods are used to judge whether there is a user located at the edge of the cell:

(1) Compare the RSRP information of the local cell and the RSRP information of the neighboring cell reported by the user. When the difference between the two values is within a certain range, it is judged that the user is located at the edge of the cell;

(2) The small base station obtains the coordinate location information of the user, and judges whether the user is located at the edge of the cell.

If no user is located at the edge of the cell, the small base station enters the power adjustment process and proceeds to step S4; if there is a user located at the edge of the cell, the small base station starts the dormancy process and proceeds to step S5;

Step S4: Since no user in the small base station is located at the edge of the cell, the transmission power of the small base station is appropriately reduced to narrow its coverage area, which can not only reduce the downlink interference to neighboring cells, but also save energy consumption. The small base station continuously monitors the load of the cell. When a new user is detected and the load level remains unchanged, it is judged by the user location information whether the user is located at the edge of the cell. If it is located at the edge of the cell, the base station transmit power is increased and the step S5, if it is located in the center of the cell, continue to maintain the original state; when it is detected that a new user enters and the load level changes, enter step S7;

Step S5: If there is a user located at the edge of the cell, the dormancy process is started, and firstly it is judged whether the current cell brings downlink interference to neighboring cells. When the neighboring cell detects that the small base station is lightly loaded through the records in the ANR, it sends the "indication of inter-cell interference" information to the small base station. Wherein, only when the "inter-cell interference indication" information changes, it is updated and sent to the small base station.

In the present invention, the following two methods are used to judge the level of interference that this cell brings to neighboring cells:

(1) The adjacent cell sets an interference threshold, and the home user of the adjacent cell reports the detected RSRP of the small base station. If the RSRP of the small base station exceeds the interference threshold, when the adjacent cell sends the "inter-cell interference indication" information, the corresponding Mark the PRB resources, and after receiving the "inter-cell interference indication" information, the small base station counts the number of PRBs exceeding the interference threshold threshold; when the number of PRBs exceeding the interference threshold exceeds a certain percentage, it is considered a high interference level, otherwise it is considered a high interference level. low interference level;

(2) The adjacent cell compares the measured RSRP of the small base station reported by its home user with the set interference threshold, and counts the number of PRBs exceeding the interference threshold; if the number of PRBs exceeds a certain ratio, determine the interference level as Otherwise, it is determined that the interference level is low, and the level of the interference level is identified in the "inter-cell interference indication" information sent to the small base station.

After the small base station receives the "inter-cell interference indication" information of the neighboring cell, it determines the level of interference caused by the cell to the neighboring cell according to the information; if the interference level is low, it exits the dormancy process and enters step S6; if it is If the interference level is high, it is determined that the small base station enters a dormant state, and proceeds to step S8;

Step S6: The small base station continuously detects the load of the cell. If a new user access is detected and the load level changes, go to step S7; if the load level continues to be light load, update the received "inter-cell interference indication" information , to determine the level of interference brought by the cell to the neighboring cells;

Step S7: If the small base station detects that the load level is moderate load or full load, the small base station sleep process is ended, and at the same time, the small base station continues to detect the load of the cell;

Step S8: The small base station determines to enter the dormant state, and handovers its own users to the neighboring small base station or the macro base station. After the user handover is completed, the small base station enters the dormant state. Among them, the principle for the home user to select a handover base station is: to select a small base station with a moderate load first, and if there is no small base station that meets the requirements, then switch to a macro base station.

To sum up, the method for controlling the dormancy of small base stations based on the load and interference level of the present invention controls the dormancy state of the small base station in the hierarchical networking scenario by judging the service load of the cell and the generated interference level, thereby effectively Reduce the interference in the hierarchical networking scenario, especially the downlink interference caused by reference signals, improve the system throughput, ensure the effective operation of the system, save energy consumption, and realize green communication. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (7)

1. control a method for little base station dormancy based on load and interference level, it is characterized in that, at least comprise the following steps:

Step S1: mutual cell load class information between little base station, little base station continues to detect this cell load;

Step S2: when little base station detect the grade of load of this community be intermediate part load and full load time, little base station continue detect this cell load; When little base station detects that this cell load grade is extra-light loading, determine that little base station enters resting state, proceed to step S8; When detecting that this cell load grade is underload when little base station, enter step S3;

Step S3: judge whether have user to be positioned at cell edge position in the home subscriber of little base station; If do not have user to be positioned at cell edge, little base station ingoing power regulates process, proceeds to step S4; If there is user to be positioned at cell edge, little base station initiated sleeping process, proceeds to step S5;

Step S4: reduce little base station transmitting power, and continue to monitor the cell load of little base station, when detecting that new user enters and the grade of load is constant, judge whether whether this user is positioned at cell edge, if this user is positioned at cell edge, then increase base station transmitting power, and proceed to step S5, if this user is positioned at center of housing estate, then remain stationary in little base station; When detecting that new user enters and the grade of load changes, enter step S7;

Step S5: little base station judges the height of this community whether to the interference level that adjacent cell is brought according to " presence of intercell interference instruction " information that adjacent cell sends; If be low interference level, then exit sleeping process, enter step S6; If be high interference levels, then determine that little base station enters resting state, proceed to step S8;

Step S6: little base station continues detected cells load, if detect that new user accesses and causes the grade of load to change, proceeds to step S7; If the grade of load is continuously underload, then upgrades " presence of intercell interference instruction " information received, judge the height of this community to the interference level that adjacent cell is brought;

Step S7: if little base station detects that the grade of load is intermediate part load or full load, then little base station continues to detect this cell load;

Step S8: little base station home subscriber is switched to contiguous little base station or macro base station, after completing user switches, little base station enters resting state.

2. the method controlling little base station dormancy based on load and interference level according to claim 1, it is characterized in that: the cell load grade of little base station comprises extra-light loading, underload, intermediate part load and full load, the grade of load information of adjacent cell is recorded in the Automatic Neighboring Relation of little base station by little base station.

3. the method controlling little base station dormancy based on load and interference level according to claim 1, is characterized in that: in step S3, has judged whether that user is positioned at cell edge position by following two kinds of methods:

By the difference of these two information, A, this community RSRP information comparing user's report and adjacent cell RSRP information, judge whether this user is positioned at cell edge;

B, judge whether user is positioned at cell edge by user coordinates positional information.

4. the method controlling little base station dormancy based on load and interference level according to claim 1, it is characterized in that: in step S5, " presence of intercell interference instruction " information that little base station sends according to adjacent cell judges that whether this community is as follows to the method for the height of the interference level that adjacent cell is brought:

Adjacent cell sets an interference threshold threshold value, adjacent cell home subscriber reports the RSRP of the little base station detected, if the RSRP of little base station exceedes interference threshold threshold value, when adjacent cell sends " presence of intercell interference instruction " information, at the enterprising line identifier of PRB resource of correspondence, after information that little base station receives " presence of intercell interference instruction ", statistics exceedes the PRB number of interference threshold threshold value; When the PRB number exceeding interference threshold threshold value exceedes certain proportion, then think high interference levels, otherwise think low interference level.

5. the method controlling little base station dormancy based on load and interference level according to claim 1, it is characterized in that: in step S5, " presence of intercell interference instruction " information that little base station sends according to adjacent cell judges that whether this community is as follows to the method for the height of the interference level that adjacent cell is brought:

Adjacent cell compares the RSRP of the little base station measured and the interference threshold threshold value of setting that its home subscriber reports, and statistics exceedes the PRB number of interference threshold threshold value; If the PRB number exceeding interference threshold threshold value exceedes certain proportion, be then defined as high interference levels, otherwise be defined as low interference level, and identify the height of interference level in " presence of intercell interference instruction " information.

6. the method controlling little base station dormancy based on load and interference level according to claim 1, it is characterized in that: only have when " presence of intercell interference instruction " information of adjacent cell changes, " presence of intercell interference instruction " information after renewal can be resend little base station.

7. the method controlling little base station dormancy based on load and interference level according to claim 1, it is characterized in that: in step S8, selecting the principle of base station shifting for home subscriber is: the little base station of prioritizing selection intermediate part load, if do not have satisfactory little base station, is then switched to macro base station.