Relay control system, relay device, and relay control method

Abstract

The present invention relates to a relay control system for wireless communication, and has the objective of reducing network cost and facilitating securing of an installation place. A relay device 40 comprises a reflector unit 48 including a plurality of reflector elements that each provide an independent phase shift to an incoming wave, a communication unit 42 that receives transmission point information from one or a plurality of transmission points 30, an element allocation unit 44 that determines the allocation of the plurality of reflector elements, and a phase control unit 46 that provides a phase weight to each of the plurality of reflector elements. The element allocation unit 44 determines, on the basis of the transmission point information, the number of communication links to be established via the relay device 40, determines the number of reflector elements to be allocated to each of the communication links, and determines the reflector elements to be allocated to each of the communication links according to the number. The phase control unit 46 determines the phase weight such that a beam directed toward a reception point to which each communication link communicates is generated by a reflected wave generated by each of the reflector elements allocated to each of the communication links.

Description

[Technical field]

[0001] The present disclosure relates to a relay control system, a relay device, and a relay control method, and more particularly to a relay control system, a relay device, and a relay control method that relay wireless communications using a dynamic reflector. [Background technology]

[0002] The following non-patent documents 1 and 2 disclose techniques that use a dynamic reflector (RIS: Reconfigurable Intelligent Surface) as a relay device for wireless communication.

[0003] Fig. 1 shows a conventional configuration of a wireless communication relay control system using a RIS. The system shown in Fig. 1 includes a transmission point 10, a reception point 12, and a RIS 20. The transmission point 10 is composed of a wireless base station or the like under the management of a telecommunications carrier. The reception point 12 is composed of a user terminal such as a smartphone. The RIS 20 is arranged to relay wireless signals between the transmission point 10 and the reception point 12.

[0004] 2 shows the configuration of a conventional RIS 20. The RIS 20 includes a communication unit 22. The communication unit 22 receives information required for controlling the RIS 20 from the transmitting point 10 or the receiving point 12. The control information acquired by the communication unit 22 is provided to a phase control unit 24.

[0005] The phase control section 24 performs processing for controlling the phase to be given to the reflected wave based on the above control information. The result of the phase control is provided to the reflecting section 26.

[0006] The reflecting unit 26 includes a number of reflecting elements arranged two-dimensionally. Each reflecting element can reflect an incoming wave in a high frequency band after controlling the phase. The above-mentioned phase control is performed for each of the reflecting elements included in the reflecting unit 26. When appropriate phase control is performed for each of the reflecting elements, the communication wave reflected by the reflecting unit 26 becomes a beam heading in a specific direction.

[0007] In a situation where an obstacle exists between the transmitting point 10 and the receiving point 12, it may be difficult to directly transmit and receive a radio signal between the transmitting point 10 and the receiving point 20. In such a case, if the RIS 20 generates a beam toward the receiving point 12 by phase control, good reception characteristics can be obtained at the receiving point 12. Therefore, the RIS 20 is useful in expanding the coverage in the high frequency band. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Wireless Communications Through Reconfigurable Intelligent Surfaces, ERTUGRUL BASAR, MARCO DI RENZO, JULIEN DE ROSNY, MEROUANE DEBBAH, MOHAMED-SLIM ALOUINI, RUI ZHANG, p116753-116773, VOLUME 7, 2019, IEEE Access, August 13, 2019 [Non-Patent Document 2] Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming, Qingqing Wu, Rui Zhang, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, p5394-5409, VOL. 18, NO. 11, November 2019 Summary of the Invention [Problem to be solved by the invention]

[0009] In the conventional relay control system, the RIS 20 is arranged to connect one transmitting point 10 and one receiving point 12. Meanwhile, in the field of wireless communication, an increase in transmitting points is expected with the trend toward distributed antennas and small cells. If a RIS 20 is to be installed at each transmitting point, network costs will rise. Also, as the number of RIS 20 required for installation increases, it becomes difficult to secure installation locations.

[0010] The present disclosure has been made in consideration of the above-mentioned problems, and has a first objective to provide a relay control system that reduces network costs and makes it easy to secure installation locations by using a relay device that reflects incoming waves from each of a plurality of transmitting points toward each of a plurality of receiving points.

[0011] A second object of the present disclosure is to provide a relay device that reduces network costs and makes it easy to secure installation space by reflecting incoming waves from multiple transmitting points toward multiple receiving points.

[0012] A third object of the present disclosure is to provide a relay control method that reduces network costs and makes it easy to secure installation locations by using a relay device that reflects incoming waves from each of a plurality of transmitting points toward each of a plurality of receiving points. [Means for solving the problem]

[0013] In order to achieve the above object, a first aspect is a relay control system using a relay device having a plurality of reflecting elements each capable of imparting an independent phase shift to an incoming wave, the relay control system comprising: A communication unit that receives transmission point information from one or more transmission points; an element allocation unit that determines an allocation of the plurality of reflecting elements based on the transmission point information; a phase control unit that gives a phase weight to each of the plurality of reflecting elements, The element allocation unit determining the number of communication links to be established via the relay device based on the transmission point information; an element number determination process for determining the number of reflecting elements to be assigned to each of the communication links; determining a reflecting element to be assigned to each of the communication links according to the determined number; It is desirable that the phase control unit is configured to perform a process of determining the phase weight so that a beam directed toward a receiving point which is the communication destination of each communication link is generated by the reflected waves generated by each of the reflecting elements assigned to each of the communication links.

[0014] A second aspect is a relay device, a reflecting section including a plurality of reflecting elements each capable of imparting an independent phase shift to an incoming wave; A communication unit that receives transmission point information from one or more transmission points; an element allocation unit that determines an allocation of the plurality of reflecting elements based on the transmission point information; a phase control unit that gives a phase weight to each of the plurality of reflecting elements, The element allocation unit determining the number of communication links to be established based on the transmission point information; determining a number of reflective elements to allocate to each of said communication links; determining a reflecting element to be assigned to each of the communication links according to the determined number; It is desirable that the phase control unit is configured to perform a process of determining the phase weight so that a beam directed toward a receiving point which is the communication destination of each communication link is generated by the reflected waves generated by each of the reflecting elements assigned to each of the communication links.

[0015] A third aspect is a relay control method using a relay device having a plurality of reflecting elements each capable of imparting an independent phase shift to an incoming wave, the method comprising the steps of: receiving transmission point information from one or more transmission points; an element allocation step of determining an allocation of the plurality of reflecting elements based on the transmission point information; a phase control step of giving a phase weight to each of the plurality of reflecting elements; The element allocation step includes: determining a number of communication links to be established via the relay device based on the transmission point information; determining a number of reflective elements to allocate to each of said communication links; determining a reflecting element to be assigned to each of the communication links according to the determined number. It is desirable that the phase control step includes a step of determining the phase weight so that a beam directed toward a receiving point which is the communication destination of each communication link is generated by the reflected waves generated by each of the reflecting elements assigned to each of the communication links. Effect of the Invention

[0016] According to the first to third aspects, a single relay device can reflect incoming waves from a plurality of transmission points toward a plurality of reception points, respectively. Therefore, according to these aspects, in a situation where a large number of transmission points exist, it is possible to reduce network costs and easily secure installation locations, compared to a case where one relay device is set for each transmission point. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram for explaining a configuration of a conventional relay control system using a relay device. [Diagram 2] FIG. 1 is a block diagram for explaining a configuration of a conventional relay device. [Diagram 3] FIG. 1 is a diagram for explaining a configuration of a relay control system according to a first embodiment of the present disclosure. [Figure 4] 4 is a block diagram for explaining the configuration of a relay device included in the relay control system shown in FIG. 3. [Diagram 5]5A to 5C are diagrams illustrating a configuration of a reflector included in the relay device according to the first embodiment of the present disclosure. [Figure 6] 4 is a flowchart illustrating an operation of the relay control system according to the first embodiment of the present disclosure. [Figure 7] FIG. 4 is a diagram for explaining a characteristic operation of the relay device according to the first embodiment of the present disclosure. [Figure 8] FIG. 11 is a diagram for explaining a configuration of a relay control system according to a second embodiment of the present disclosure. [Figure 9] 9 is a block diagram for explaining the configuration of a control device included in the relay control system shown in FIG. 8. [Figure 10] 9 is a block diagram for explaining the configuration of a relay device included in the relay control system shown in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Embodiment 1 [Configuration of the first embodiment] Fig. 3 shows a configuration of a relay control system according to the first embodiment of the present disclosure. The system shown in Fig. 3 includes a first transmission point 30-1 and a first reception point 32-1, as well as a second transmission point 30-2 and a second reception point 32-2. Hereinafter, when it is not necessary to distinguish between the first transmission point 30-1 and the second transmission point 30-2, the subscripts of the symbols will be omitted and they will be simply referred to as "transmission point 30". Similarly, when it is not necessary to distinguish between the first reception point 32-1 and the second reception point 32-2, they will be simply referred to as "reception point 32".

[0019] In this embodiment, the transmission point 30 is composed of a wireless base station or the like under the management of a telecommunications carrier. Meanwhile, the reception point 32 is composed of a user terminal such as a smartphone. If the reception point 32 belongs to the communication area of ​​the transmission point 30 and there is no obstacle between them, the reception point 32 can directly communicate with the transmission point 30.

[0020] The relay control system of this embodiment includes a relay device 40. The relay device 40 is configured by a dynamic reflector, that is, a RIS (Reconfigurable Intelligent Surface). The relay device 40 is disposed to relay a wireless signal between a transmission point 30 and a reception point 32. Even if the reception point 32 cannot directly communicate with the transmission point 30, it may be possible for the reception point 32 to communicate with the transmission point 30 via the relay device 40.

[0021] 4 is a block diagram for explaining the configuration of the relay device 40. As shown in FIG. 4, the relay device 40 includes a communication unit 42. The communication unit 42 is a block for transmitting and receiving control information between the transmission point 30 and the reception point 32 for use in controlling the relay device 40. The control information acquired by the communication unit 42 is provided to an element allocation unit 44 and a phase control unit 46. In addition, the processing result of the element allocation unit 44 is provided to the phase control unit 46. In addition, the processing result of the phase control unit 46 is provided to a reflection unit 48.

[0022] FIG. 5 is a diagram for explaining the configuration of the reflecting unit 48. As shown in FIG. 5, the reflecting unit 48 includes a plurality of reflecting elements 50. The reflecting elements 50 are regularly arranged at equal intervals in a two-dimensional manner. Each of the reflecting elements 50 has a mechanism for reflecting or transmitting the radio wave emitted by the transmission point 30. An individual ID is assigned to each of the reflecting elements 50, and they can be controlled independently of each other. More specifically, each of the reflecting elements 50 can add a desired phase weight to an incoming wave to generate a reflected wave with a desired phase shift.

[0023] The phase shift can be generated, for example, by connecting a variable phase shifter that gives an arbitrary phase shift to each reflecting element 50. Alternatively, the phase shift may be generated using a device that can control the phase in two values ​​by turning a switch on and off. Also, the phase of the incoming wave reflected by the reflecting element 50 may be shifted by other methods.

[0024] The description will be continued with reference to Fig. 4 again. A control signal for each of the reflecting elements 50 is provided to the reflecting unit 48 from the phase control unit 46. This control signal includes a phase weight command for each of the reflecting elements 50. The phase weight can be calculated, for example, by a method of performing channel estimation, a method using position information (see, for example, Japanese Patent No. 5200090), or other known methods.

[0025] As described above, the phase control unit 46 is provided with the processing result of the element allocation unit 44. The element allocation unit 44 is a block that determines how to allocate the reflecting elements 50 of the reflecting unit 48 based on the control information received from the communication unit 42. Specifically, the element allocation unit 44 determines the number of communication links that the relay device 40 should handle based on the control information from the communication unit 42. For example, when the communication unit 42 receives control information from two transmission points 30-1 and 30-2, it determines that there are two communication links.

[0026] The element allocation unit 44 then determines the number of reflecting elements 50 to be assigned to each of the communication links. Furthermore, the element allocation unit 44 specifically determines the reflecting elements 50 to be assigned to each of the communication links based on the determined numbers. Then, the element allocation unit 44 provides the result of the determination to the phase control unit 46.

[0027] The phase control unit 46 provides control signals to the reflecting elements 50 assigned to the respective communication links to realize phase shifts appropriate for the respective communication links. As a result, a single repeater 40 generates a plurality of reflected waves that establish a plurality of communication links.

[0028] [Operation of the first embodiment] Fig. 6 is a flowchart for explaining the operation of the relay control system shown in Fig. 3. In the example shown in Fig. 6, first, the first transmission point 30-1 generates transmission point information (step 100). Next, the second transmission point 30-2 generates transmission point information (step 102).

[0029] The above transmission point information includes, for example, some or all of the following information: (1) Transmission point identification number (2) Frequency channel (3) Number of required reflectors (4) Location and installation height of the transmission point (5) Traffic volume (this may be cumulative traffic, time-averaged traffic volume, or measured traffic volume over a certain period of time) (6) Number of connected terminals (number of receiving points to establish communication)

[0030] The transmission point information generated by the first transmission point 30-1 and the second transmission point 30-2 are both received by the relay device 40. Based on the information, the relay device 40 first determines that the number of communication links to be established is two. Next, the relay device 40 determines the number of reflective elements 50 to be assigned to each transmission point 30 and the element ID (step 104).

[0031] Specifically, the allocation of the reflective elements 50 is calculated based on an "allocation index" set by the following method. Note that the following methods may be selectively used as a single method, or two or more methods may be used in combination.

[0032] (1) An allocation index is set according to the “required number of reflecting elements” included in the transmission point information. This makes it possible to meet the requirements of each transmission point 30.

[0033] (2) An allocation index is set according to the distance between each transmission point 30 and the relay device 40. Specifically, first, the distance between the transmission point 30 and the relay device 40 is calculated based on the "location information" included in the transmission point information. This calculation may be performed by the relay device 40, or may be performed by an external control device (not shown) and the result may be provided to the relay device 40. The relay device 40 allocates more reflecting elements as the distance increases. The longer the propagation distance is, the more the incoming wave from the transmission point 30 attenuates. According to the above method, the effect of attenuation can be suppressed by allocating more reflecting elements to an incoming wave with large attenuation.

[0034] (3) An allocation index is set according to the "traffic volume" included in the transmission point information. The relay device 40 allocates many reflecting elements 50 to transmission points 30 with a large traffic volume. This makes it possible to generate a strong reflected wave for transmission points 30 with a large traffic volume, and creates an environment in which good communication quality can be easily ensured.

[0035] (4) An allocation index is set according to the "number of connected terminals" included in the transmission point information. The relay device 40 allocates many reflecting elements 50 to a transmission point to which a large number of terminals are connected. This makes it possible to prevent the number of reflecting elements 50 allocated to each terminal from becoming unbalanced.

[0036] After setting the “allocation index”, relay device 40 calculates the number of reflecting elements 50 allocated to each transmission point according to the following formula. (Number of allocated elements) = (total number of reflecting elements) × (allocation index of target transmission point) / (total amount of allocation index) (1) Here, the “total amount of allocation indicators” is the sum of the “allocation indicators” for all transmission points 30 .

[0037] It is also possible to assign a weight to each transmission point and replace the above formula (1) with the following formula (2). The weight can be set between "0" and "1", and is set so that the sum of the weights of each transmission point is "1". (Number of allocated elements) = (total number of reflecting elements) × (weight of target transmission point) × (allocation index of target transmission point) / (total amount of allocation index) (2)

[0038] According to the technique using the above formula (2), by giving a large weight to a specific transmission point 30, it is possible to create an environment in which communication related to that transmission point 30 is given priority over communication related to other transmission points 30.

[0039] FIG. 7 shows an example of allocation of reflecting elements 50 to two transmission points 30 having the same allocation conditions, that is, both the "allocation index" and the "weight". Here, among the multiple reflecting elements 50 included in the reflector 48, the left half element group 50-1 is assigned to the first transmission point 30-1, and the right half element group 50-2 is assigned to the second transmission point 30-2. However, the allocation method is not limited to such a simple division, and as long as the allocation number is satisfied, the combination of elements to be specifically allocated can be freely set, including random combinations. In addition, the number of transmission points 30 is not limited to two, and the number may be three or more, and the reflecting elements 50 may be allocated to three or more transmission points 30. Through the above process, the ID of the reflecting element 50 assigned to each transmission point 30 is linked to the transmission point 30 to which it is assigned.

[0040] 6, next, the phase to be added to each of the reflecting elements 50 is determined (step 106). This process is performed so that a beam is generated toward the receiving point 32, which is the communication destination of each transmitting point 30, by the reflected wave generated by each of the reflecting elements 50 associated with each transmitting point 30.

[0041] However, when one transmitting point 30 communicates with two or more receiving points 32, multiple communication links are established for the transmitting point 30. Then, a reflecting element 50 is assigned to each of the multiple communication links. In this case, the process of step 106 is performed so that a beam directed toward the receiving point 32, which is the communication destination of each communication link, is generated by the reflected wave generated by each reflecting element assigned to each communication link.

[0042] 6, following the process of step 106, a wireless signal is transmitted from the first transmission point 30-1 (step 108). This signal is reflected by the reflecting element 50 assigned to the first transmission point 30-1 in the relay device 40. As a result, this signal becomes a beam directed toward the first reception point 32-1 and is received by the first reception point 32-1 via the first communication link (step 110).

[0043] 6, a wireless signal is also transmitted from the second transmission point 30-2 (step 112). This signal is reflected by the reflecting element 50 assigned to the second transmission point 30-2 in the relay device 40. As a result, this signal becomes a beam directed toward the second reception point 32-2 and is received by the second reception point 32-2 via the second communication link (step 114).

[0044] As described above, according to the relay control system of this embodiment, a single relay device 40 can be used to establish a plurality of communication links connecting each of the plurality of transmission points 30 with each of the plurality of reception points 32. Therefore, according to this system, compared to the conventional configuration in which one relay device 40 is installed for each transmission point 30, it is possible to reduce network costs and to easily secure installation locations for the relay devices 40.

[0045] Embodiment 2 Next, a second embodiment of the present disclosure will be described with reference to FIGS. Fig. 8 is a diagram for explaining the configuration of a relay control system according to the second embodiment of the present disclosure. In Fig. 8, the same elements as those shown in Fig. 3 are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

[0046] The relay control system of this embodiment is similar to the relay control system of the first embodiment, except that the functions of the relay device 40 are distributed between the control device 60 and the relay device 70. More specifically, in this embodiment, the element allocation function provided in the relay device 40 in the first embodiment is provided in the control device 60, not in the relay device 70.

[0047] [Features of the second embodiment] Fig. 9 is a block diagram for functionally explaining the configuration of the control device 60 shown in Fig. 8. As shown in Fig. 9, the control device 60 in this embodiment includes a communication unit 42 and an element allocation unit 44. These function in the same manner as the communication unit 42 and the element allocation unit 44 included in the relay device 40 in the first embodiment. That is, in this embodiment, the control unit 60 installed separately from the relay device 70 receives transmission point information from each of the transmission points 30, and determines the number and IDs of the reflecting elements 50 to be allocated to each transmission point 30 based on the transmission point information.

[0048] Fig. 10 is a block diagram for functionally explaining the configuration of the relay device 70 shown in Fig. 8. As shown in Fig. 10, the relay device 70 in this embodiment includes a communication unit 72. The communication unit 72 is a block for receiving the result of element allocation, that is, the ID information of the reflecting elements 50 assigned to each transmission point 30, from the control device 60. The phase control unit 46 of the relay device 70 provides phase weight information to each of the reflecting elements 50 according to the ID information received in this manner, as in the case of the first embodiment.

[0049] As a result, the relay control system of this embodiment, like the first embodiment, can use one relay device 70 to establish a plurality of communication links connecting each of the plurality of transmission points 30 and each of the plurality of reception points 32. Therefore, like the first embodiment, the system of this embodiment can obtain sufficient coverage while suppressing network costs and easily securing installation locations for relay devices 40. [Explanation of symbols]

[0050] 30, 30-1, 30-2 Transmission points 32, 32-1, 32-2 receiving points 40, 70 Relay device 42 Communications Department 44 Element allocation section 46 Phase control section 48 Reflector 50 Reflective elements 50-1 Left half element group 50-2 Right half element group 60 Control device

Claims

1. A relay control system using a relay device having a plurality of reflecting elements each capable of imparting an independent phase shift to an incoming wave, comprising: A communication unit that receives transmission point information from one or more transmission points; an element allocation unit that determines an allocation of the plurality of reflecting elements based on the transmission point information; a phase control unit that gives a phase weight to each of the plurality of reflecting elements, The element allocation unit determining the number of communication links to be established via the relay device based on the transmission point information; an element number determination process for determining the number of reflecting elements to be assigned to each of the communication links; determining a reflecting element to be assigned to each of the communication links according to the determined number; The phase control unit is configured to execute a process of determining the phase weight so that a beam directed toward a receiving point, which is the communication destination of each communication link, is generated by the reflected waves generated by each of the reflecting elements assigned to each of the communication links.

2. The transmission point information includes a required number of reflecting elements required by the transmission point, 2. The relay control system according to claim 1, wherein the element number determination process includes a process of determining the number of reflecting elements to be assigned to the communication link based on the required number of reflecting elements.

3. the transmission point information includes a distance between the transmission point and the relay device, 3. The relay control system according to claim 1, wherein the element number determination process includes a process of determining the number of reflecting elements to be assigned to the communication link based on the distance.

4. The transmission point information includes a traffic volume of communication at the transmission point, 4. The relay control system according to claim 1, wherein the element number determination process includes a process of determining the number of reflecting elements to be assigned to the communication link based on the traffic volume.

5. The transmission point information includes the number of terminals connected to the transmission point, 5. The relay control system according to claim 1, wherein the element number determination process includes a process of determining the number of reflecting elements to be assigned to the communication link based on the number of the terminals.

6. The element allocation unit further executes a process of acquiring weights defined for each of the transmission points when a plurality of transmission points to which the communication link should be established are recognized; 6. The relay control system according to claim 1, wherein the element number determination process further includes a process of reflecting the weights in the number of reflecting elements to be assigned to the communication link.

7. a reflecting section including a plurality of reflecting elements each capable of imparting an independent phase shift to an incoming wave; A communication unit that receives transmission point information from one or more transmission points; an element allocation unit that determines an allocation of the plurality of reflecting elements based on the transmission point information; a phase control unit that gives a phase weight to each of the plurality of reflecting elements, The element allocation unit determining the number of communication links to be established based on the transmission point information; determining a number of reflective elements to allocate to each of said communication links; determining a reflecting element to be assigned to each of the communication links according to the determined number; The phase control unit is a relay device configured to perform a process of determining the phase weight so that a beam directed toward a receiving point, which is the communication destination of each communication link, is generated by the reflected waves generated by each of the reflecting elements assigned to each of the communication links.

8. 1. A relay control method using a relay device having a plurality of reflecting elements each capable of imparting an independent phase shift to an incoming wave, comprising the steps of: receiving transmission point information from one or more transmission points; an element allocation step of determining an allocation of the plurality of reflecting elements based on the transmission point information; a phase control step of giving a phase weight to each of the plurality of reflecting elements; The element allocation step includes: determining a number of communication links to be established via the relay device based on the transmission point information; determining a number of reflective elements to allocate to each of said communication links; determining a reflecting element to be assigned to each of the communication links according to the determined number. A relay control method, wherein the phase control step includes a step of determining the phase weight so that a beam directed toward a receiving point which is the communication destination of each communication link is generated by the reflected waves generated by each of the reflecting elements assigned to each of the communication links.

Images