Base station and communication terminal

Abstract

To provide a base station capable of preventing resource waste in a communication system in which a relay device also performs beam control.SOLUTION: A base station 3 in a communication system in which communication is performed between a base station 3 and a communication terminal 1 via a relay device 2 receives information on a schedule for performing beam control between the communication terminal 1 and the relay device 2 from the communication terminal 1 (S2), and notifies the communication terminal 1 of control information for not allocating resources to the communication terminal 1 when the communication terminal 1 is performing beam control in the schedule (S3, S4).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a base station and a communication terminal in a communication system in which a relay device also performs beam control. [Background technology]

[0002] In the conventional non-patent documents 1 and 2, a communication system has been proposed in which communication between a base station (BS) and a user terminal (UE) is performed by dynamic beamforming, and in order to select an optimal combination from among a plurality of beam patterns, one or more beam patterns are selected from the observation results of the synchronization signal (PSS / SSS) and reference signal (CSI-RS) transmitted by each beam pattern of the BS while switching the beam pattern on the UE side within a beam selection time (Beam Sweeping Period), and the selected beam patterns are fed back to the BS together with the observation results (RSRP / RSRQ). Based on the feedback, the BS determines the beam to be used in communication with the UE, and communicates with the UE using the determined beam. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP(registered trademark) TR38.802, V14.1.0: "Study on new radio access technology physical layer aspects (Release 14)," Jun. 2017. [Non-Patent Document 2] 3GPP(registered trademark), TS 38.214, "NR Physical layer procedures for data," v16.6.0, Jun. 2021. Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, wireless relay devices, also known as radio frequency repeaters (RF repeaters), are used to expand the area coverage of BSs and improve the communication environment of UEs located in dead spots within the area coverage. Conventional technologies that do not consider how to handle RF repeaters when performing dynamic beamforming in relay devices also have the problem that resources allocated by BSs to UEs may be wasted.

[0005] Fig. 1 is a diagram showing a schematic diagram of the problem of the conventional technology. In step a, a base station (BS) performs beam sweeping, i.e., transmission by sequentially switching among a plurality of beam patterns that indicate the directivity of transmission and reception of electromagnetic waves, and a communication terminal (UE) evaluates the communication quality of the plurality of beam patterns by measuring the beams via a relay device (Rep), and the base station determines the beam pattern to be used for communication with the communication terminal via the relay device from the evaluation result. Based on the determination, in step b, the base station allocates a PDCCH (Physical Downlink Control Channel). In accordance with the allocation, the base station transmits downlink data by a PDSCH (Physical Downlink Shared Channel) as in step c.

[0006] However, in a configuration in which the relay device also performs beam sweeping, it is necessary to appropriately re-establish the access link between the communication terminal and the relay device (access link) by the communication terminal performing beam sweeping (and beam measurement) periodically or in an event-driven manner triggered by the detection of a link disconnection, as in step d. During step d when the beam is being swept, the link between the communication terminal and the relay device is not established in the first place, so if steps c and d overlap in time, step c will be wasted, and the resources allocated to the communication terminal in step b will be wasted.

[0007] In view of the problems of the related art, a first object of the present invention is to provide a base station capable of preventing waste of resources in a communication system in which a relay device also performs beam control. A second object of the present invention is to provide a communication terminal capable of preventing waste of resources in a communication system in which a relay device also performs beam control. [Means for solving the problem]

[0008] In order to achieve the first object, the present invention has a first feature in which a base station in a communication system in which communication is performed between a base station and a communication terminal via a relay device receives schedule information from the communication terminal for performing beam control between the communication terminal and the relay device, and, when the communication terminal is performing beam control on the schedule, notifies the communication terminal of control information that prevents resources from being allocated to the communication terminal.

[0009] In order to achieve the second object, the present invention has a second feature in that a communication terminal in a communication system in which communication is performed between a base station and a communication terminal via a relay device notifies the base station of schedule information for performing beam control between the communication terminal and the relay device, and receives control information notified by the base station of the schedule, which prevents resources from being allocated to the communication terminal when the communication terminal is performing beam control. Effect of the Invention

[0010] According to the first or second feature, by using information on a schedule for performing beam control between a communication terminal and a relay device, when the communication terminal is performing beam control in that schedule, resources are not allocated to the communication terminal, and those resources are made available for resource allocation to other communication terminals, thereby preventing waste of resources. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a problem with the conventional technology. [Diagram 2] 1 is a configuration diagram of a communication system according to an embodiment. [Diagram 3] FIG. 2 is a diagram showing an operation sequence of a communication system according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 2 is a configuration diagram of a communication system 100 according to an embodiment. The communication system 100 includes a communication terminal (UE) 1, a relay device (Rep) 2, and a base station (BS) 3. The communication terminal 1 includes a UE communication unit 11 and a UE control unit 12. The relay device 2 includes a UE side communication unit 21, a BS side communication unit 22, and a Rep control unit 23. The base station 3 includes a BS communication unit 31 and a BS control unit 32.

[0013] Each of the UE control unit 12, the Rep control unit 23, and the BS control unit 32 can be configured with a processor such as a CPU, a RAM, a ROM, etc., and can perform control processing by executing a predetermined program and processing for storing information required for the control processing. The UE control unit 12 controls communication by the UE communication unit 11, the Rep control unit 23 controls communication by the UE side communication unit 21 and the BS side communication unit 22, and the BS control unit 32 controls communication by the BS communication unit 31.

[0014] The communication terminal 1 and the relay device 2 communicate on an access link by wireless communication between the UE communication unit 11 and the UE side communication unit 21, and the relay device 2 and the base station 3 communicate on a backhaul link by wireless communication between the BS side communication unit 22 and the BS communication unit 31. The UE communication unit 11, the UE side communication unit 21, the BS side communication unit 22, and the BS communication unit 31 can all perform directional communication by switching between multiple beam patterns.

[0015] 3 is a diagram showing an operation sequence of the communication system 100 according to an embodiment. Step S1 is the same as step a, in which the base station 3 performs beam sweeping of a plurality of beam patterns, and the communication terminal 1 evaluates the communication quality of the plurality of beam patterns by measuring the beam via the relay device 2, and the base station 3 determines the beam pattern to be used for communication with the communication terminal 1 via the relay device 2 from the evaluation result. By step S1, a link between the base station 3 and the relay device 2 and a link between the relay device 2 and the communication terminal 1 are established, and communication between the base station 3 and the communication terminal 1 is possible via the relay device 2. This step S1 may be realized using any existing method, and the base station 3 and the communication terminal 1 may directly communicate with each other during the process, or the base station 3 side may take the initiative in establishing the link, or the communication terminal 1 side may take the initiative in establishing the link.

[0016] In step S2, the communication terminal 1 determines the timing, time width, period, etc. of the beam control as a schedule for the beam control of the access link to be performed by itself in order to re-establish the access link, and then notifies the base station 3 of the schedule via the relay device 2 to make a schedule request. The communication terminal 1 may determine the schedule for the beam control by any method such as a rule base based on its own moving speed or the communication quality with the relay device 2. Alternatively, a predetermined beam control schedule that is set in advance according to the day of the week, region, time period, etc. may be used. Note that with respect to the communication between the relay device 2 and the communication terminal 1, the beam on the side of the relay device 2 may be omnidirectional. If there are multiple relay devices 2, the communication terminal 1 may determine the schedule for any one of them (for example, the one with the best communication quality).

[0017] In step S3, the base station 3 performs scheduling in accordance with the schedule requested by the communication terminal 1 in step S2, thereby allocating resources to the communication terminal 1 and other communication terminals (not shown) other than the communication terminal 1. That is, the scheduling for allocating RBs (which determine which of a plurality of subcarriers (frequencies) is allocated to which communication terminal at each time (slot) as a resource block) to be used between the communication terminal 1 and other communication terminals is performed by not allocating resources to the communication terminal 1 during a time period (slot) in which the communication terminal 1 is performing beam control with the relay device 2, and by allowing the allocation of resources to the communication terminal 1 during a time period in which the communication terminal 1 is not performing beam control with the relay device 2, assuming that the constraint notified in step S2 is satisfied.

[0018] In step S4, the base station 3 notifies the communication terminal 1 via the relay device 2 of the beam control slot scheduled in step S3.

[0019] In step S5, the communication terminal 1 performs beam control in accordance with the notification in step S4. For example, as shown in Fig. 3, if the contents of the schedule are set so that the time length of the beam control cycle is T3, and beam control is performed in the first half of the beam control cycle, and the second half of the beam control cycle, time length T2 (T1+T2=T3), is outside the beam control time, the communication terminal 1 repeatedly performs an operation according to the setting in the cycle T3.

[0020] Here, since the base station 3 performed scheduling in step S3 in accordance with the beam control schedule of the communication terminal 1, it is possible to effectively utilize resources. That is, during time T1 during which the communication terminal 1 is performing beam control, no resources are allocated to the communication terminal 1, and the unallocated resources are made available for resource allocation to other communication terminals, and during time T2 outside the beam control time of the communication terminal 1, resource allocation to the communication terminal 1 is permitted, so that by preventing unnecessary resource allocation during beam control, it is possible to effectively utilize resources.

[0021] Hereinafter, the embodiments of the present invention will be described with reference to various supplementary examples, alternative examples, additional examples, and the like.

[0022] (1) An embodiment of the present invention can contribute to the development of communications infrastructure, and therefore contribute to Goal 9 of the United Nations Sustainable Development Goals (SDGs), which is to “build resilient infrastructure, promote sustainable industrialization, and foster innovation.”

[0023] (2) In step S2, the communication terminal 1 can use a method for making a schedule request to the base station 3, such as PRACH (Physical Random Access Channel), PUCCH (Physical Uplink Control Channel), or SRS (Sounding Reference Signal).

[0024] (3) In step S2, when the communication terminal 1 sends a schedule request to the base station 3, the contents of the request can include beam control timing, the number of slots required for beam control, and the period of beam control.

[0025] (4) In step S4, the base station 3 can notify the communication terminal 1 of the result of allocation of the beam control resources using a PDCCH (Physical Downlink Control Channel). [Explanation of symbols]

[0026] 100 communication system, 1 communication terminal, 2 relay device, 3 base station 11 UE communication unit, 12 UE control unit, 21 UE side communication unit, 22 BS side communication unit, 23 Rep control unit, 31 BS communication unit, 32 BS control unit

Claims

1. A base station in a communication system in which communication is performed between the base station and a communication terminal via a relay device, A base station characterized by receiving from the communication terminal schedule information for performing beam control between the communication terminal and the relay device, and notifying the communication terminal of control information for not allocating resources to the communication terminal when the communication terminal is performing beam control on the schedule.

2. 2. The base station according to claim 1, wherein the control information is notified to the communication terminal using a PDCCH (Physical Downlink Control Channel).

3. The base station according to claim 1 , wherein the schedule information includes a timing of beam control, a required number of slots, or a period.

4. The base station according to claim 1 , wherein the control information permits allocation of resources to the communication terminal when the communication terminal is not performing beam control in the schedule.

5. A communication terminal in a communication system in which communication is performed between a base station and a communication terminal via a relay device, notifying the base station of schedule information for performing beam control between the communication terminal and the relay device; A communication terminal characterized by receiving control information notified from the base station to which the schedule is notified, which prevents resources from being allocated to the communication terminal when the communication terminal is performing beam control.

6. The communication terminal according to claim 5, characterized in that the schedule information is notified to the base station using a PRACH (Physical Random Access Channel), a PUCCH (Physical Uplink Control Channel), or an SRS (Sounding Reference Signal).

7. 6. The communication terminal according to claim 5, wherein the schedule information includes a timing of beam control, a required number of slots, or a period.

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