Processing device for cell-free communication system, method and program executed by said processing device

Abstract

To suppress power consumption of a cell-free communication system.SOLUTION: A method executed by a processing apparatus includes: executing, when one or more first APs that are changed from a cluster AP to a non-cluster AP due to a change of a cluster which is an aggregate of APs related to a radio device occur, first processing on one or more processing target APs including the one or more first APs and a second AP that is the non-cluster AP satisfying a predetermined condition in relation to the processing target APs, and thereby determining, as an operation mode of the one or more processing target APs, any one of a downstream-only mode in which the reception of a radio signal is not performed, an upstream-only mode in which the transmission of a radio signal is not performed and a sleep mode in which the transmission / reception of a radio signal is not performed. The first processing includes selecting one first processing target AP from the processing target APs, determining the downstream-only mode as the operation mode of the one first processing target AP, and determining the upstream-only mode or the sleep mode as the operation mode of the other second processing target AP.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a self - contained communication system.

Background Art

[0002] A cellular communication system provides services by dividing a service - providing area into a plurality of cells and arranging base stations in each cell. In a cellular communication system, a wireless device (WD), also called a user equipment (UE), communicates with the base station of the cell in which the WD is located. In a cellular communication system, due to the power attenuation of radio waves from the base station and interference from neighboring cells, the communication quality in the boundary region of the cell is likely to deteriorate.

[0003] For this reason, Non - Patent Document 1 discloses a self - contained communication system. In a self - contained communication system as well, similar to a cellular communication system, a plurality of access points (APs) are arranged at various geographical locations. The plurality of APs are connected to a central processing unit (CPU) via a transmission line. In a self - contained communication system, for example, the CPU selects one or more APs with which the WD communicates wirelessly from among the plurality of APs. The WD communicates with the CPU via the one or more APs by transmitting and receiving wireless signals with the one or more APs selected by the CPU.

[0004] In a self - contained communication system, there is no concept of a conventional "cell", and one or more APs that communicate with the WD are dynamically controlled by the CPU for each WD. This set of one or more APs that communicate with the WD is also called the "cluster" of the WD or the "cluster" associated with the WD.

[0005] Non - Patent Document 2 discloses a cluster formation process for forming a cluster of the WD when the WD initially accesses a self - contained communication system.

Prior Art Documents

Non - Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Even in a cell-free communication system, it is desired to suppress its power consumption.

[0008] This disclosure provides a technique for suppressing the power consumption of a cell-free communication system.

Means for Solving the Problems

[0009] According to one aspect of the present disclosure, a method executed by a processing device of a self-free communication system including a plurality of access points (APs) is as follows. When one or more first APs are changed from cluster APs included in the cluster to non-cluster APs not included in the cluster due to a change in a cluster that is a set of APs associated with a wireless device, the method includes executing a first process using the one or more first APs and the second APs, which are non-cluster APs satisfying a predetermined condition with respect to the one or more first APs, as one or more processing target APs, thereby determining an operation mode of the one or more processing target APs to be any one of a downlink dedicated mode in which reception of a wireless signal is not performed, an uplink dedicated mode in which transmission of a wireless signal is not performed, and a sleep mode in which transmission and reception of a wireless signal are not performed, and controlling the one or more processing target APs to operate in the operation mode determined in the first process. The first process includes selecting one first processing target AP from the one or more processing target APs, determining the operation mode of the one first processing target AP to be the downlink dedicated mode, and determining the operation mode of a second processing target AP different from the first processing target AP among the one or more processing target APs to be the uplink dedicated mode or the sleep mode.

Effect of the Invention

[0010] According to the present disclosure, the power consumption of the self-free communication system can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of the features described in the embodiments are essential for the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Also, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0013] FIG. 1 is a configuration diagram of a self-free communication system used in the description of the embodiment. In FIG. 1, the self-free communication system has a plurality of APs 1-1 to 1-10. In the following description, when there is no need to distinguish between APs 1-1 to 1-10, they are denoted as AP1. In FIG. 1, the number of APs 1 is exemplified as 10, but the number of APs 1 in the self-free communication system is not limited to 10. Each AP1 is connected by a wired and / or wireless communication link to a CPU 3. Further, the CPU 3 is connected to a core network (not shown). Note that in FIG. 1, for simplicity of the figure, the communication links connecting each AP1 and the CPU 3 are omitted.

[0014] Also, FIG. 1 shows two WDs 2-1 and 2-2. In the following description, when there is no need to distinguish between WDs 2-1 and 2-2, they are denoted as WD2. APs 1-1 to 1-3 and 1-5 within the solid-line circle in FIG. 1 are the cluster 4-1 of WD2-1. Also, APs 1-5, 1-7, and 1-10 within the dotted-line circle in FIG. 1 are the cluster 4-2 of WD2-2. Therefore, WD2-1 communicates wirelessly with APs 1-1 to 1-3 and 1-5 included in the cluster 4-1, and communicates with the CPU 3 via APs 1-1 to 1-3 and 1-5. Similarly, WD2-2 communicates wirelessly with APs 1-5, 1-7, and 1-10 included in the cluster 4-2, and communicates with the CPU 3 via APs 1-5, 1-7, and 1-10.

[0015] In the following description, AP1 included in any cluster of WD2 is denoted as cluster AP, and AP1 not included in any cluster is denoted as non-cluster AP. In FIG. 1, AP1-1, AP1-2, AP1-3, AP1-5, AP1-7, and AP1-10 are cluster APs. On the other hand, in FIG. 1, AP1-4, AP1-6, AP1-8, and AP1-9 are non-cluster APs.

[0016] CPU3 dynamically controls the clusters of each WD2. Therefore, in FIG. 1, although AP1-2 is a cluster AP, due to the movement of WD2-1, AP1-2 can be removed from cluster 4-1 and become a non-cluster AP. Conversely, in FIG. 1, although AP1-9 is a non-cluster AP, it can be included in cluster 4-2 due to the movement of WD2-2 and become a cluster AP.

[0017] In this embodiment, AP1 is configured to operate in any one of four operating modes. The first operating mode is the normal mode that performs both transmission and reception of wireless signals. The second operating mode is the downlink dedicated mode that transmits wireless signals but does not receive wireless signals. The downlink dedicated mode is a mode for notifying WD2 of the presence of AP1, and AP1 set to the downlink dedicated mode broadcasts synchronization signals, system information, etc. The wireless signal reception circuit of AP1 operating in the downlink dedicated mode is set to a state with less power consumption than the wireless signal reception circuit of AP1 operating in the normal mode.

[0018] The third operating mode is the uplink dedicated mode that receives signals from WD2 and transmits them to CPU3 but does not transmit wireless signals. The wireless signal transmission circuit of AP1 operating in the uplink dedicated mode is set to a state with less power consumption than the wireless signal transmission circuit of AP1 operating in the normal mode. The fourth operating mode is the sleep mode that does not perform transmission and reception of wireless signals. Both the wireless signal transmission circuit and the reception circuit of AP1 operating in the sleep mode are set to states with less power consumption than AP1 operating in the normal mode.

[0019] The power consumption of AP1 is the largest in the normal mode, the second largest in the downstream dedicated mode, the third largest in the upstream dedicated mode, and the smallest in the sleep mode.

[0020] In this embodiment, the CPU 3 determines the operation mode of AP1. First, for the operation mode of the cluster AP, the CPU 3 determines it to be the normal mode. On the other hand, the CPU 3 determines the operation mode of the non-cluster AP by the process shown in FIG. 2. Hereinafter, the flowchart of FIG. 2 will be described.

[0021] In S10, the CPU 3 initializes the counter value C to 0. In S11, the CPU 3 determines whether there is one or more AP1s that have become non-cluster APs due to being removed from the cluster with the change of the cluster. Although not shown in the flowchart, if there are one or more AP1s that have become cluster APs from non-cluster APs due to the change of the cluster, the CPU 3 sends a control signal to this one or more AP1s to set this AP1 to the normal mode. If there are one or more AP1s that have become non-cluster APs from cluster APs, the CPU 3 determines in S13 whether the counter value C is a positive predetermined value. If the counter value C is not a positive predetermined value, the CPU 3 performs the first process described later in S16 and increases the counter value by 1 in S17. Thereafter, the CPU 3 repeats the process from S11.

[0022] On the other hand, in S11, if there are no one or more AP1s that have become non-cluster APs from cluster APs, the CPU 3 determines in S12 whether the processing timing has arrived. The processing timing is periodic timing. Note that the period of the processing timing is set longer than the average period during which the cluster is changed. If the processing timing has not arrived, the CPU 3 repeats the process from S11. On the other hand, if the processing timing has arrived, the CPU 3 performs the second process described later in S14, initializes the counter value C to 0 in S15, and repeats the process from S11. Note that in S13, when the counter value C is a positive predetermined value, the CPU 3 also performs the second process in S14.

[0023] Summarizing the flowchart of FIG. 2, when one or more APs 1 that have become non-cluster APs from the cluster AP of the cluster are generated due to the change of the cluster, the CPU 3 basically performs the first process. When changes in a plurality of clusters are performed substantially simultaneously and there are APs 1 that have become non-cluster APs from the cluster AP for each cluster, the CPU 3 individually performs the first process for each cluster. Further, the CPU 3 performs the second process at a predetermined cycle. However, when the first process is performed a predetermined number of times between the timing of performing the second process and the timing of performing the next second process, the CPU 3 performs the second process.

[0024] First, the first process will be described. The CPU 3 determines a non-cluster AP whose distance from any one of one or more APs 1 that have become non-cluster APs due to the change of the cluster is within a threshold value. Hereinafter, one or more APs 1 that have become non-cluster APs from the cluster AP and a non-cluster AP whose distance from any one of the one or more APs 1 is within the threshold value are referred to as processing target APs. When the number of processing target APs is 3 or more, the CPU 3 determines the distance between any pair of the processing target APs, and determines the operation mode of the processing target AP with the smallest variance of the distances from the other processing target APs as the downlink dedicated mode. This corresponds to setting the processing target AP close to the center of the area where the processing target APs are arranged to the downlink dedicated mode. When the number of processing target APs is 1, the CPU 3 determines the operation mode of this processing target AP as the downlink dedicated mode. When the number of processing target APs is 2, the CPU 3 determines one processing target AP by an arbitrary method and determines the operation mode of the determined processing target AP as the downlink dedicated mode.

[0025] When the number of APs to be processed is two or more, for the remaining APs to be processed, about half of them are set to the uplink dedicated mode, and the remaining about half are set to the sleep mode. For example, CPU3 determines the number of APs to be processed in the uplink dedicated mode to be the same as or one more than the number of APs to be processed in the sleep mode. Note that CPU3 determines the operation modes of the remaining APs to be processed so that the APs to be processed in the uplink dedicated mode are not geographically concentrated. After determining the operation modes of the APs to be processed, CPU3 sends a control signal to the APs to be processed to control them to operate in the determined operation modes.

[0026] Subsequently, the second process will be described. In the second process, at least all non-cluster APs among the APs managed by CPU3 are the processing targets. First, CPU3 groups all non-cluster APs based on their deployment locations, for example, by using the K-means method. Note that the number of groups is a function of the number of clusters, and the larger the number of clusters within the range from the lower limit value to the upper limit value, the smaller it is. For each group, CPU3 determines the operation modes of the non-cluster APs included in the group by performing the first process with the non-cluster APs included in the group as the APs to be processed.

[0027] The power consumption of the self-free communication system is minimized, for example, by setting all non-cluster APs to the sleep mode. However, when there is only an AP1 in the sleep mode around the WD2 in the idle mode, the WD2 in the idle mode cannot recognize the presence of AP1. Therefore, it is necessary to provide the AP1 operating in the downlink dedicated mode in a geographically dispersed manner. Also, it is necessary to provide the AP1 in the uplink dedicated mode, which receives a random access signal or the like transmitted when the WD2 in the idle mode accesses the self-free communication system and sends it to CPU3, in a geographically dispersed manner.

[0028] In this embodiment, each time a non-cluster AP occurs, the operation mode of the non-cluster APs within a predetermined area centered on the non-cluster AP is determined. At this time, by operating the non-cluster APs near the center of the predetermined area in the downlink dedicated mode, it is possible to prevent a state in which WD2 cannot receive the signal from AP1. Furthermore, by operating approximately half of the remaining non-cluster APs within the predetermined area in the uplink dedicated mode, it is possible to prevent a state in which the wireless signal transmitted by WD2 cannot be transmitted to CPU3.

[0029] In this way, by providing non-cluster APs that operate in the downlink dedicated mode within the range necessary for the idle-mode WD2, non-cluster APs that operate in the uplink dedicated mode, and operating the rest in the sleep mode, the power consumption of the self-free communication system can be suppressed.

[0030] Note that the first process is a local process for determining the operation mode of the non-cluster APs within a predetermined area centered on the arrangement position of AP1 that has become a non-cluster AP. Therefore, if only the first process is repeated, for example, a geographical bias in the operation mode of the non-cluster APs may occur. For this reason, in this embodiment, the second process is performed each time the first process is performed a predetermined number of times or when a predetermined period has elapsed.

[0031] In the second process, the non-cluster APs are grouped based on the arrangement positions of all the non-cluster APs managed by at least CPU3, and one non-cluster AP that operates in the downlink dedicated mode is determined for each group. Then, the remaining AP1s in the group are operated in the uplink dedicated mode or the sleep mode. With this configuration, it is possible to prevent the non-cluster APs operating in the downlink dedicated mode or the uplink dedicated mode from being geographically biased.

[0032] FIG. 3 is a configuration diagram of the processing device 5 according to the present embodiment. The processing device 5 can be implemented, for example, in the CPU 3. The processing device 5 includes one or more processors 50 and one or more memory devices 51 that store a computer program. The one or more memory devices 51 are non-transitory computer-readable storage media. When the computer program is executed by the one or more processors 50, it includes instructions for causing the one or more processors 50 to execute the processing in the CPU 3 described in FIG. 2.

[0033] Further, the processing device 5 includes a database unit 52. The database unit 52 is a database indicating the arrangement positions of the respective APs 1 of the self-free communication system. Note that the present disclosure is not limited to the configuration in which the processing device 5 has the database unit 52. For example, the database unit 52 can be provided in an external device accessible by the processing device 5 via a network.

[0034] FIG. 4 shows functional blocks realized in the processing device 5 when the one or more processors 50 execute a computer program stored in the one or more memory devices 51. As shown in FIG. 4, the one or more processors 50 function as an operation mode determination unit 55 and an operation mode control unit 56.

[0035] The operation mode determination unit 55 executes the processing shown in FIG. 2 to determine the operation mode of each AP 1. The operation mode control unit 56 controls each AP 1 so that each AP 1 operates according to the operation mode determined by the operation mode determination unit 55.

[0036] In the above-described embodiment, in the first process, the CPU 3 targeted for processing one or more APs 1 that changed from cluster APs to non-cluster APs and non-cluster APs whose distance from any one of the one or more APs 1 was within the threshold value. However, the present disclosure is not limited to a form in which the target AP for processing is determined based on the distance from one or more APs 1 that changed from cluster APs to non-cluster APs. For example, it is possible to target for processing one or more APs 1 that changed from cluster APs to non-cluster APs and non-cluster APs whose path loss value from any one of the one or more APs 1 is within a predetermined value.

[0037] Furthermore, according to the present disclosure, a program executable by one or more processors is provided. When the program is executed by one or more processors of the device, the program includes instructions for causing the device to function as, for example, the processing device 5. Furthermore, according to the present disclosure, a non-transitory computer-readable storage medium storing the above program is provided. Furthermore, according to the present disclosure, a method executed by the processing device 5 is provided according to the content described in FIG. 2. Furthermore, according to the present disclosure, a program for causing a device having one or more processors to execute the method and a non-transitory computer-readable storage medium storing the program are provided.

[0038] The invention is not limited to the above-described embodiment, and various modifications and changes are possible within the scope of the gist of the invention.

[0039] With the above configuration, it is possible to suppress the power consumption of the self-free communication system. Therefore, it becomes possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization, and foster innovation."

Description of Reference Numerals

[0040] 55: Operation mode determination unit, 56: Operation mode control unit

Claims

1. 1. A method executed by a processor in a cell-free communication system having a plurality of access points (APs), comprising: When a change in a cluster, which is a collection of APs associated with a wireless device, occurs such that one or more first APs are changed from cluster APs included in the cluster to non-cluster APs not included in the cluster, a first process is executed with the one or more first APs and a second AP, which is the non-cluster AP and satisfies a predetermined condition with respect to the one or more first APs, as one or more processing target APs, thereby determining the operation mode of the one or more processing target APs to be one of a downlink only mode in which wireless signals are not received, an uplink only mode in which wireless signals are not transmitted, and a sleep mode in which wireless signals are not transmitted or received; Controlling the one or more target APs to operate in the operation mode determined in the first process; Including, The first process includes: selecting one first processing target AP from the one or more processing target APs, and determining an operation mode of the one first processing target AP to be the downlink only mode; determining an operation mode of a second processing target AP, which is different from the first processing target AP, among the one or more processing target APs, to be the uplink only mode or the sleep mode; A method comprising:

2. 2. The method of claim 1 , When the one or more processing target APs are three or more, The method, wherein the first processing target AP is a processing target AP having the smallest variance of distances to other processing target APs among the one or more processing target APs.

3. 2. The method of claim 1 , When there are two or more processing target APs, A method according to claim 1, wherein the number of the second process target APs determined to be in the uplink only mode in the first process is equal to or is one more than the number of the second process target APs determined to be in the sleep mode.

4. 2. The method of claim 1 , determining the operation mode of one or more third APs operating as the non-cluster AP among the plurality of APs by executing a second process at a predetermined period; Controlling the one or more third APs to operate in the operation mode determined in the second process; Further comprising: The second process includes: Determining the number of groups; Grouping the one or more third APs into the determined number of groups based on placement positions of the one or more third APs; Executing the first process with one or more fourth APs included in the group as the one or more process target APs; A method comprising:

5. 5. The method of claim 4, A method according to claim 1, wherein the number of groups is a function of the number of clusters of the cell-free communication system.

6. 6. The method of claim 5, The method of claim 1, wherein the number of groups is smaller the larger the number of clusters.

7. 5. The method of claim 4, When the one or more first APs occur after performing the second process and performing the first process a predetermined number of times, executing the second process instead of the first process; Controlling the one or more third APs to operate in the operation mode determined in the second process; A method comprising:

8. 2. The method of claim 1 , When one or more fifth APs are changed from the non-cluster APs to the cluster APs, determining the operation mode of the one or more fifth APs to a normal mode for transmitting and receiving wireless signals; Controlling the one or more fifth APs to operate in the normal mode; A method comprising:

9. 2. The method of claim 1 , The method, wherein the predetermined condition is met when a distance to the one or more first APs is within a threshold or a path loss to the one or more first APs is within a predetermined value.

10. one or more processors; A memory device for storing a program; A processing device for a cell-free communication system comprising: A processing device, the program, when executed by the one or more processors, causing the processing device to perform the method of any one of claims 1 to 9.

11. A program which, when executed by one or more processors of a processing device of a cell-free communication system, causes said processing device to carry out the method of any one of claims 1 to 9.

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