Repeater, and traffic off-loading method

Abstract

The present invention relates to a method for utilizing a repeater (e.g., NCR) that relays services between a base station and a terminal as an entity that forms the repeater's coverage and simultaneously as an entity that collects and performs traffic offloading-related information.

Description

Technology Field

[0001] The present invention relates to repeater technology for relaying services between a base station and a terminal. Background Technology

[0002] Currently, repeater technology has been utilized to relay services by amplifying and transmitting signals between base stations and terminals. As this repeater technology has advanced, smart repeater technology, or Network-Controlled Repeater (NCR), has emerged, going beyond the level of simple signal amplification and transmission.

[0003] NCR technology is a 5G-Advanced standard-based technology for improving service coverage and network performance in mobile communication systems.

[0004] Unlike existing 5G repeaters that only performed the role of simple signal amplification / transmission, NCR is expected to support various functions by being equipped with the ability to receive and process network control information.

[0005] In particular, as a repeater for coverage expansion, NCR can plan inter-cell traffic off-loading and traffic steering by dynamically forming coverage through NCR sharing technology.

[0006] However, in order to implement traffic offloading in this way, complex procedures based on backhaul (Xn interface) must be added, and in recent O-RAN environments, there is a limitation that a third-party arbitration server such as RIC (Ran Intelligent Controller) must be established.

[0007] Accordingly, the present invention proposes a new inter-cell traffic offloading method based on NCR arbitration (NCR-coordinated). The problem to be solved

[0008] The present invention has been created in consideration of the above-mentioned circumstances, and the objective to be achieved by the present invention is to utilize a repeater (e.g., NCR) that relays services between a base station and a terminal as both the entity forming the repeater's coverage and, at the same time, as the entity collecting and performing traffic offloading-related information. means of solving the problem

[0009] A repeater according to one embodiment of the present invention for achieving the above objective comprises: a memory including instructions; and a processor that, by executing the instructions, determines two or more candidate cells sharing the repeater based on the reception strength of a Synchronization Signal Block (SSB) radiated from an adjacent cell, and forms the coverage of the repeater as the coverage of a specific candidate cell among the two or more candidate cells based on a traffic comparison result using traffic-related information collected from the two or more candidate cells.

[0010] Specifically, the above two or more candidate cells receive the SSB with a reception strength greater than or equal to a reference size, and the difference in reception strength of the SSB between cells may be less than a threshold.

[0011] Specifically, the processor may perform an initial attachment to the first candidate cell when a first candidate cell and a second candidate cell exist, and the reception strength of the SSB radiated from the first candidate cell is greater than that of the second candidate cell, thereby forming the coverage of the relay device as the coverage of the first candidate cell.

[0012] Specifically, the processor collects traffic-related information from the first candidate cell upon initial attachment to the first candidate cell, and when a certain waiting time has elapsed after collecting the traffic-related information, if there is no terminal serviced by the first candidate cell within the coverage of the relay device, the processor may switch to attachment to the second candidate cell and collect traffic-related information from the second candidate cell.

[0013] Specifically, the processor may form the coverage of the relay device as the coverage of the first candidate cell when there is a first candidate cell and a second candidate cell, and the traffic comparison result shows that the traffic of the first candidate cell is less than the traffic of the second candidate cell by more than a threshold.

[0014] Specifically, the coverage of the relay device may apply a scheduling method of stacking PRBs (Physical Resource Blocks) along one direction in the frequency domain when forming the coverage of the first candidate cell, in a direction different from that of the scheduling method of the second candidate cell.

[0015] A traffic offloading method performed in a repeater according to an embodiment of the present invention for achieving the above objective comprises: a determination step of determining two or more candidate cells in which the difference in reception strength of an SSB (Synchronization Signal Block) between cells is less than a threshold value based on the reception strength of an SSB radiated from an adjacent cell; and a control step of forming the coverage of the repeater as the coverage of a specific candidate cell among the two or more candidate cells according to a traffic comparison result using traffic-related information collected from the two or more candidate cells.

[0016] Specifically, the control step may perform an initial attachment to the first candidate cell when a first candidate cell and a second candidate cell exist, and the reception strength of the SSB radiated from the first candidate cell is greater than that of the second candidate cell, thereby forming the coverage of the relay device as the coverage of the first candidate cell.

[0017] Specifically, the control step collects traffic-related information from the first candidate cell upon initial attachment to the first candidate cell, and when a certain waiting time has elapsed after collecting the traffic-related information, if there is no terminal serviced by the first candidate cell within the coverage of the relay device, the attachment can be switched to the second candidate cell to collect traffic-related information from the second candidate cell.

[0018] Specifically, the control step may form the coverage of the relay device as the coverage of the first candidate cell when there is a first candidate cell and a second candidate cell, and the traffic comparison result shows that the traffic of the first candidate cell is less than the traffic of the second candidate cell by more than a threshold.

[0019] Specifically, the coverage of the relay device may apply a scheduling method of stacking PRBs (Physical Resource Blocks) along one direction in the frequency domain when forming the coverage of the first candidate cell, in a direction different from that of the scheduling method of the second candidate cell. Effects of the invention

[0020] According to the relay device and traffic offloading method of the present invention, in amplifying / transmitting signals between a base station and a terminal, it is possible to operate as a subject forming the coverage of the relay device and simultaneously as a subject collecting and performing traffic offloading-related information; thus, changes and additions to subjects other than the relay device can be avoided for the exchange of traffic information between cells (or between base stations).

[0021] In addition, by applying a special scheduling method to terminals within the coverage of the relay device, it becomes possible to mitigate inter-cell interference at intermediate locations between cells, thereby preventing unnecessary degradation of throughput performance and ensuring excellent service performance for the terminals at all times. Brief explanation of the drawing

[0022] FIG. 1 is an exemplary diagram illustrating a repeater service environment according to an embodiment of the present invention. FIG. 2 is an exemplary diagram illustrating an NCR sharing-based inter-cell traffic off-loading environment according to an embodiment of the present invention. Figure 3 is an example diagram illustrating the limitations of the existing inter-cell traffic off-loading method. FIG. 4 is a configuration diagram for explaining a relay device according to an embodiment of the present invention. FIGS. 5 and 6 are exemplary diagrams for explaining a candidate cell determination process according to an embodiment of the present invention. FIG. 7 is an illustrative diagram for explaining a scheduling method according to an embodiment of the present invention. FIG. 8 is a flowchart illustrating a traffic offloading method according to an embodiment of the present invention. Specific details for implementing the invention

[0023] Hereinafter, various embodiments of the present invention will be described with reference to the attached drawings.

[0024] In one embodiment of the present invention, repeater technology for relaying services between a base station and a terminal is described.

[0025] Currently, repeater technology has been utilized to relay services by amplifying and transmitting signals between base stations and terminals. As this repeater technology has advanced, smart repeater technology, or Network-Controlled Repeater (NCR), has emerged, going beyond the level of simple signal amplification and transmission.

[0026] NCR technology is a 5G-Advanced standard-based technology for improving service coverage and network performance in mobile communication systems.

[0027] Unlike conventional 5G repeaters that only perform the role of simple signal amplification / transmission, NCR is equipped with the function of receiving and processing network control information, thereby supporting (1) adaptive / variable beamforming, (2) control of whether the repeater is operating, and (3) power control for inter-cell interference control, and various other functions.

[0028] In this regard, FIG. 1 shows a repeater service environment according to one embodiment of the present invention, that is, an environment in which a base station utilizes a repeater (e.g., NCR) to service a terminal.

[0029] As explained earlier, the core of NCR technology is that the NCR is equipped with the function of receiving and processing network control information.

[0030] Accordingly, as illustrated in Fig. 1, control information between the base station (gNB) and the repeater, i.e., the NCR, is transmitted through the Control link, transmission data between the base station (gNB) and the NCR is transmitted through the Backhaul link, and finally, transmission data between the NCR and the terminal (UE) is transmitted through the Access link.

[0031] At this time, the NCR aims to control the Backhaul link and Access link using control information obtained through the Control link to more smoothly transmit data between the base station (gNB) and the terminal (UE).

[0032] Looking at this further, the NCR forms a control link through the NCR-MT (Mobile Terminal), a backhaul panel that receives network control information signals from the base station (gNB), and forms a backhaul link and an access link through the NCR-Fwd (Forwarding), an access panel.

[0033] To this end, the donor antenna facing the base station (gNB) and the service antenna facing the terminal (UE) can be implemented as an integrated or separate type.

[0034] The most contrasting difference between such an NCR and a conventional RF repeater is the presence or absence of control signals; in this case, the NCR-MT within the NCR can be treated as a terminal that forms an independent link between the base station and the NCR (the NCR-MT possesses a full stack protocol capable of performing communication perfectly, and in actual specifications, it is referred to as an NCR device).

[0035] Therefore, the control signals handled by the NCR-MT can be configured with a high degree of freedom, which means that the control signals can be defined for roles beyond those previously discussed, such as adaptive / variable beamforming, repeater operation control, time alignment control, and power control.

[0036] Meanwhile, there is an NCR sharing technology in which NCR is not bound to a specific cell to increase the coverage of that cell by the amount of NCR coverage, but is bound to multiple cells to allow multiple cells to share the coverage of NCR.

[0037] When NCR sharing becomes possible, coverage can be configured dynamically, unlike RF repeaters that passively (blindly) perform only amplification and transmission. Since this increases the degree of freedom in repeater utilization, it leads to cost savings in terms of construction engineering.

[0038] If we look further into the effects of NCR sharing from a technical perspective, 1) there is an advantage in the mobility handling of the terminal.

[0039] In other words, assuming a situation where the NCR is bound only to cell A, when a terminal in cell B moves to the NCR coverage area, it must perform a Hand Over (HO) to cell A; however, if the NCR can also be bound to cell B, a Hand Over is not required in the same situation, making it possible to provide seamless service.

[0040] In addition, 2) it is possible to select a cell that provides a better channel environment.

[0041] That is, assuming a situation where the NCR is bound to cell A, if there is an obstacle blocking the channel between cell A and the NCR, the NCR cannot momentarily perform the bridge role; however, if the NCR can be bound to cell B in such a case, it becomes possible to provide a better channel environment for the terminal.

[0042] And, 3) traffic off-loading or traffic steering between cells is possible.

[0043] In other words, when cell A is busy and cell B is idle, NCR belongs to cell B, providing the terminal with the opportunity to be scheduled more freely, which makes it possible to increase 'spectral efficiency per unit area,' a representative metric expected when building repeaters.

[0044] In this regard, Figure 2 illustrates an example of an NCR sharing-based inter-cell traffic off-loading / traffic steering environment compared to a conventional RF repeater environment.

[0045] Below, we will take a closer look at traffic off-loading, which was mentioned above as a technical effect of NCR sharing.

[0046] Traffic offloading technology has been actively researched in various fields for a long time.

[0047] In other words, research is being conducted on heterogeneous and homogeneous networks, including offloading between Wi-Fi APs (Access Points) and cellular networks, offloading between communication technologies (e.g., LTE <-> 5G), offloading between frequency bands in Carrier Aggregation (CA), and finally, offloading between cells of the same hierarchy (same communication technology and same frequency band).

[0048] The most important key aspects of traffic offloading are 1) the quality of information that must be shared between cells, and 2) the logic and entities that decide on offloading.

[0049] To make this possible, there are two representative methods: one using backhaul between base stations as shown in Fig. 3 (a), and the other using a Ran Intelligent Controller (RIC) that is being actively developed based on O-RAN recently as shown in Fig. 3 (b).

[0050] However, in the case of the method using Backhaul in Fig. 3 (a), complex procedures must be added based on a non-ideal backhaul (Xn interface), so a new procedure definition is required (violation of Backward compatibility), and also, as shown in Fig. 3 (b), in the case of the method using RIC, there is a limitation that a third-party arbitration server such as RIC must be additionally built (offsetting the cost-saving effect of NCR).

[0051] Accordingly, in a repeater service environment according to one embodiment of the present invention, a new method for offloading inter-cell traffic based on NCR arbitration (NCR-coordinated) is proposed, and below, the configuration of an NCR (hereinafter referred to as a 'relay device') for realizing this is to be explained in more detail.

[0052] FIG. 4 shows the configuration of a relay device (100) according to one embodiment of the present invention.

[0053] As illustrated in FIG. 4, a relay device (100) according to one embodiment of the present invention may be configured to include a memory containing instructions and a processor that executes instructions within the memory.

[0054] In particular, in the case of a processor according to one embodiment of the present invention, it may have a functional configuration including a verification unit (110) and a modification unit (120) according to an implementation function according to the execution of an instruction.

[0055] For the above, the relay device (100) according to the embodiment of the present invention can operate as a subject forming the coverage of the relay device (100) in amplifying / transmitting signals between the current base station and the terminal through the functional configuration of the aforementioned processor, and simultaneously as a subject collecting and performing traffic offloading-related information. Below, a detailed explanation of each functional configuration within the processor to realize this will be provided.

[0056] The decision unit (110) is responsible for the function of determining the candidate cell.

[0057] More specifically, the decision unit (110) determines at least some of the adjacent cells as candidate cells that can be shared by the relay device (100) based on the reception strength of the SSB (Synchronization Signal Block) periodically radiated from the adjacent cells.

[0058] At this time, the decision unit (110) can determine as a candidate cell an adjacent cell in which the SSB is received with a reception strength greater than or equal to a reference size and the difference in reception strength of the SSB between cells is less than a threshold value.

[0059] Referring to FIG. 5, a situation can be illustrated where Cells A, B, and C are adjacent, and there is a blockage between the relay device (100) and Cell C, so the quality of wireless communication between the relay device (100) and Cell C cannot be guaranteed.

[0060] In this case, since the relay device (100) does not need to form coverage for Cell C, Cell C can be excluded from the candidate cells.

[0061] Additionally, in the above example, Cell A and Cell B can be candidate cells, provided that the difference in reception strength of the SSB received from Cell A and Cell B is small (below the threshold).

[0062] If the difference in reception strength of the SSB is large (SSB power from Cell A >> SSB power from Cell B), the relay device (100) provides service only for Cell A.

[0063] In other words, in this case, there is no need to share the relay device (100).

[0064] Accordingly, in one embodiment of the present invention, in order to presuppose an environment in which a relay device (100) is shared between cells, it is assumed that the relay device (100) is located at an internal division point between Cell A and Cell B.

[0065] The control unit (120) performs the function of collecting traffic-related information from candidate cells.

[0066] More specifically, when a candidate cell that can be shared by the relay device (100) is determined, the control unit (120) periodically collects traffic-related information from the candidate cell.

[0067] In this regard, the relay device (100) according to one embodiment of the present invention is presupposed to be located at an intermediate point between Cell A and Cell B, as described above with reference to FIG. 5, and thus must collect traffic-related information from both cells, rather than collecting traffic-related information from only one cell.

[0068] However, since the relay device (100) can only be attached to one cell at a specific time, a 'sneak' method is proposed.

[0069] This means that when the relay device (100) does not perform any role in a specific cell (when there is no terminal to service), it switches to attaching to another cell to collect information from the other cell.

[0070] This sneak method prevents the relay device (100) from interrupting the service to collect traffic-related information, and by consistently repeating this procedure, traffic-related information for both Cell A and Cell B can be accumulated.

[0071] In addition, to prevent frequent ping-pong, once a connection is established, it does not attempt to connect to another cell for a specific waiting time (timer).

[0072] That is, the control unit (120) can determine Cell A and Cell B as candidate cells as described above with reference to FIG. 5, and if the reception strength of the SSB radiated from Cell A is greater than that of Cell B, perform an initial attachment to Cell A, thereby forming the coverage of the relay device (100) as the coverage of Cell A as in FIG. 6 (a).

[0073] In this way, when an initial attachment to Cell A is established, the control unit (120) collects traffic-related information from Cell A.

[0074] Additionally, the control unit (120) collects traffic-related information from Cell A, and when a specific waiting time has elapsed, if there is no terminal serving Cell A, it detaches from Cell A and then switches to attaching to Cell B as shown in Fig. 6 (b) to collect the traffic-related information from Cell B.

[0075] At this time, the traffic-related information collected from Cell A and Cell B can be broadly classified into three categories.

[0076] That is, traffic-related information according to one embodiment of the present invention is representative information counted at a commercial base station, and may include, for example, 1) how many terminals a cell is connected to (RRC-connected UE), 2) how many terminals among the connected terminals are requesting traffic (DL / UL-scheduled UE), and 3) the amount of traffic actually requested by the scheduled terminals (Traffic volume).

[0077] To examine this in more detail, traffic-related information according to one embodiment of the present invention has a high correlation with one another and can be collected in the form of an averaged traffic volume contained in a control signal in the direction of a relay device (100).

[0078] For example, the more RRC-connected UEs there are, the more DL / UL-scheduled UEs there are, and in such cases, the traffic volume is usually also large.

[0079] In this case, traffic volume is the most reliable information; typically, base stations calculate an averaged traffic volume by accumulating instantaneous traffic volume, and this averaged traffic volume can be transmitted, for example, as PRB utilization ratio information during the latest timer period.

[0080] Generally, changes in cell traffic conditions are not dynamic changes in the order of seconds or minutes, but rather changes over the course of several hours, so the averaging window is also conducted on an hourly basis.

[0081] The specific timer mentioned earlier for preventing ping-pong reflects the base station's averaging window size (for example, if the averaging window is 1 hour, there is no need to repeat attach / detach cycles in 1-minute intervals because changes in traffic volume during that time will be negligible).

[0082] In addition, the control unit (120) performs the function of forming coverage based on the traffic comparison result.

[0083] More specifically, when traffic-related information is collected from a candidate cell, the control unit (120) forms the coverage of the relay device (100) as the coverage of the candidate cell based on the result of a traffic comparison using the traffic-related information between cells.

[0084] As described above with reference to FIG. 5, Cell A and Cell B are determined as candidate cells, and when the traffic between Cell A and Cell B is compared and the traffic of Cell A is less than the traffic of Cell B by more than a threshold, the control unit (120) forms the coverage of the relay device (100) as the coverage of Cell A, as shown in FIG. 6 (a) previously exemplified.

[0085] Conversely, if the traffic of Cell B is less than the traffic of Cell A by more than a threshold, the control unit (120) forms the coverage of the relay device (100) as the coverage of Cell B, as shown in Figure 6 (b) previously illustrated.

[0086] Thus, in one embodiment of the present invention, it can be seen that the coverage of the relay device (100) between cells is switched based on the condition that the traffic of a specific cell is greater than or equal to a threshold value as a result of comparing traffic between cells, and this is also intended to prevent the aforementioned attachment / detach repetition, i.e., ping-pong.

[0087] In addition, in one embodiment of the present invention, the coverage of the relay device (100) is formed as the coverage of a relatively idle cell through traffic comparison, which means that a terminal within the coverage of the relay device (100) is serviced through an idle cell, and thus, a terminal within the coverage of the relay device (100) can receive service with a higher probability and priority.

[0088] Meanwhile, according to one embodiment of the present invention, if a relay device (100) is intentionally built between cells for NCR sharing, the relay device (100) can cause severe interference between cells.

[0089] Referring to FIG. 7, when Cell A and Cell B are determined as candidate cells and the coverage of the relay device (100) is formed as the coverage of Cell A, the relay device (100) forms a beam to service a terminal within the coverage of the relay device (100), and the beam may act as interference to Cell B, which shares the relay device (100).

[0090] To prevent this, one embodiment of the present invention proposes a scheduling method for terminals within the coverage of a relay device (100).

[0091] That is, in the coverage of the relay device (100) according to one embodiment of the present invention, when forming coverage of Cell A, the scheduling method of stacking PRB (Physical Resource Block) along one direction in the frequency domain can be applied differently from the direction in the scheduling method of Cell B.

[0092] Generally, in a cell, PRBs to be scheduled are stacked in a single direction, that is, from bottom to top or top to bottom.

[0093] The example in Fig. 7 above shows a bottom-to-top method, in which terminals within the coverage of the relay device (100) proceed with scheduling in the top-to-bottom direction (opposite direction of UE scheduling within the cell coverage).

[0094] Of course, if Cell B has a very high volume of traffic (frequency band), the upper part will inevitably be subject to inter-cell interference, but in most cases, inter-cell interference can be prevented in advance.

[0095] Thus, according to one embodiment of the present invention, when a relay device (100) is constructed for the purpose of sharing between cells, a scheduling method is additionally proposed that can mitigate inter-cell interference caused by the location between cells in the frequency band.

[0096] As described above, according to the configuration of the relay device (100) according to one embodiment of the present invention, in amplifying / transmitting signals between a base station and a terminal, it is possible to operate as a subject forming the coverage of the relay device (100) and simultaneously as a subject collecting and performing traffic offloading-related information. Therefore, in the case of sharing between cells, the relay device (100) utilizes only control signals for exchanging traffic information between cells (or between base stations), so there is no need to modify the existing Xn interface or build a 3rd party arbitration server. In other words, by utilizing only the original characteristics (capabilities) of the NCR for the relay device (100), that is, for NCR-related functions, changes and additions to entities other than the NCR can be avoided. Furthermore, by applying a special scheduling method to terminals within the coverage of the relay device (100), it becomes possible to reduce inter-cell interference at an intermediate location between cells, thereby allowing for the reduction of unnecessary throughput performance and, furthermore, ensuring excellent service performance for the terminal at all times.

[0097] Hereinafter, a traffic offloading method according to an embodiment of the present invention will be described with reference to FIG. 8.

[0098] For convenience of explanation, in the following description, the relay device (100) described with reference to FIG. 4 will be referred to as the entity performing the traffic offloading method.

[0099] First, the relay device (100) determines at least some of the adjacent cells as candidate cells that can be shared by the relay device (100) based on the reception strength of the SSB (Synchronization Signal Block) periodically radiated from the adjacent cells (S110-S120).

[0100] At this time, the relay device (100) can determine as a candidate cell an adjacent cell in which the SSB is received with a reception strength greater than or equal to a reference size and the difference in reception strength of the SSB between cells is less than a threshold value.

[0101] Referring to Figure 5, which was previously exemplified, it can be assumed that Cells A, B, and C are adjacent, and there is a blockage between the relay device (100) and Cell C, so the quality of wireless communication between the relay device (100) and Cell C cannot be guaranteed.

[0102] In this case, since the relay device (100) does not need to form coverage for Cell C, Cell C can be excluded from the candidate cells.

[0103] In addition, in this case, Cell A and Cell B can be candidate cells, provided that the difference in reception strength of the SSB received from Cell A and Cell B is small (below the threshold).

[0104] If the difference in reception strength of the SSB is large (SSB power from Cell A >> SSB power from Cell B), the relay device (100) provides service only for Cell A.

[0105] In other words, in this case, there is no need to share the relay device (100).

[0106] Accordingly, in one embodiment of the present invention, in order to presuppose an environment in which a relay device (100) is shared between cells, it is assumed that the relay device (100) is located at an internal division point between Cell A and Cell B.

[0107] Then, when a candidate cell that can be shared by the relay device (100) is determined, the relay device (100) periodically collects traffic-related information from the candidate cell (S130).

[0108] In this regard, the relay device (100) according to one embodiment of the present invention is presupposed to be located at an intermediate point between Cell A and Cell B, as described above with reference to FIG. 5, and thus must collect traffic-related information from both cells, rather than collecting traffic-related information from only one cell.

[0109] However, since the relay device (100) can only be attached to one cell at a specific time, a 'sneak' method is proposed.

[0110] This means that when the relay device (100) does not perform any role in a specific cell (when there is no terminal to service), it switches to attaching to another cell to collect information from the other cell.

[0111] This sneak method prevents the relay device (100) from interrupting the service to collect traffic-related information, and by consistently repeating this procedure, traffic-related information for both Cell A and Cell B can be accumulated.

[0112] In addition, to prevent frequent ping-pong, once a connection is established, it does not attempt to connect to another cell for a specific waiting time (timer).

[0113] That is, the relay device (100) determines Cell A and Cell B as candidate cells as described above with reference to FIG. 5, and when the reception strength of the SSB radiated from Cell A is greater than that of Cell B, it performs an initial attachment to Cell A, thereby forming the coverage of the relay device (100) as the coverage of Cell A as shown in FIG. 6 (a) previously exemplified (S120).

[0114] And, in this way, when an initial attachment to Cell A is established, the relay device (100) collects traffic-related information from Cell A.

[0115] Subsequently, the relay device (100) can collect traffic-related information from Cell A, and when a specific waiting time has elapsed, if there is no terminal serving Cell A, it can detach from Cell A and then switch to attaching to Cell B as shown in the example in Fig. 6 (b) above to collect the traffic-related information from Cell B.

[0116] At this time, the traffic-related information collected from Cell A and Cell B can be broadly classified into three categories.

[0117] That is, traffic-related information according to one embodiment of the present invention is representative information counted at a commercial base station, and may include, for example, 1) how many terminals a cell is connected to (RRC-connected UE), 2) how many terminals among the connected terminals are requesting traffic (DL / UL-scheduled UE), and 3) the amount of traffic actually requested by the scheduled terminals (Traffic volume).

[0118] To examine this in more detail, traffic-related information according to one embodiment of the present invention has a high correlation with one another and can be collected in the form of an averaged traffic volume contained in a control signal in the direction of a relay device (100).

[0119] For example, the more RRC-connected UEs there are, the more DL / UL-scheduled UEs there are, and in such cases, the traffic volume is usually also large.

[0120] In this case, traffic volume is the most reliable information; typically, base stations calculate an averaged traffic volume by accumulating instantaneous traffic volume, and this averaged traffic volume can be transmitted, for example, as PRB utilization ratio information during the latest timer period.

[0121] Generally, changes in cell traffic conditions are not dynamic changes in the order of seconds or minutes, but rather changes over the course of several hours, so the averaging window is also conducted on an hourly basis.

[0122] The specific timer mentioned earlier for preventing ping-pong reflects the base station's averaging window size (for example, if the averaging window is 1 hour, there is no need to repeat attach / detach cycles in 1-minute intervals because changes in traffic volume during that time will be negligible).

[0123] Afterwards, when traffic-related information is collected from a candidate cell, the relay device (100) forms the coverage of the relay device (100) as the coverage of the candidate cell based on the result of a traffic comparison using the traffic-related information between cells (S140-S180).

[0124] As described above with reference to FIG. 5, Cell A and Cell B are determined as candidate cells, and when the traffic between Cell A and Cell B is compared and the traffic of Cell A is less than the traffic of Cell B by more than a threshold, the control unit (120) forms the coverage of the relay device (100) as the coverage of Cell A, as shown in FIG. 6 (a) previously exemplified.

[0125] Conversely, if the traffic of Cell B is less than the traffic of Cell A by more than a threshold, the control unit (120) forms the coverage of the relay device (100) as the coverage of Cell B, as shown in Figure 6 (b) previously illustrated.

[0126] Thus, in one embodiment of the present invention, it can be seen that the coverage of the relay device (100) between cells is switched based on the condition that the traffic of a specific cell is greater than or equal to a threshold value as a result of comparing traffic between cells, and this is also intended to prevent the aforementioned attachment / detach repetition, i.e., ping-pong.

[0127] In addition, in one embodiment of the present invention, the coverage of the relay device (100) is formed as the coverage of a relatively idle cell through traffic comparison, which means that a terminal within the coverage of the relay device (100) is serviced through an idle cell, and thus, a terminal within the coverage of the relay device (100) can receive service with a higher probability and priority.

[0128] Meanwhile, according to one embodiment of the present invention, if a relay device (100) is intentionally built between cells for NCR sharing, the relay device (100) can cause severe interference between cells.

[0129] Referring to Figure 7, which was previously illustrated, Cell A and Cell B are determined as candidate cells, and when the coverage of the relay device (100) is formed as the coverage of Cell A, the relay device (100) forms a beam to service a terminal within the coverage of the relay device (100), and the beam may act as interference to Cell B, which shares the relay device (100).

[0130] To prevent this, one embodiment of the present invention proposes a scheduling method for terminals within the coverage of a relay device (100).

[0131] That is, in the coverage of the relay device (100) according to one embodiment of the present invention, when forming coverage of Cell A, the scheduling method of stacking PRB (Physical Resource Block) along one direction in the frequency domain can be applied differently from the direction in the scheduling method of Cell B.

[0132] Generally, in a cell, PRBs to be scheduled are stacked in a single direction, that is, from bottom to top or top to bottom.

[0133] The example in Fig. 7 above shows a bottom-to-top method, in which terminals within the coverage of the relay device (100) proceed with scheduling in the top-to-bottom direction (opposite direction of UE scheduling within the cell coverage).

[0134] Of course, if Cell B has a very high volume of traffic (frequency band), the upper part will inevitably be subject to inter-cell interference, but in most cases, inter-cell interference can be prevented in advance.

[0135] Thus, according to one embodiment of the present invention, when a relay device (100) is constructed for the purpose of sharing between cells, a scheduling method is additionally proposed that can mitigate inter-cell interference caused by the location between cells in the frequency band.

[0136] As described above, according to the traffic offloading method according to one embodiment of the present invention, in amplifying / transmitting signals between a base station and a terminal, it is possible to operate as a subject forming the coverage of the relay device (100) and simultaneously as a subject collecting and performing traffic offloading-related information. Therefore, in the shared situation of the relay device (100) between cells, since only the control signal is utilized for the exchange of traffic information between cells (or between base stations), there is no need to modify the existing Xn interface or build a 3rd party arbitration server. In other words, by utilizing only the original characteristics (capabilities) of the NCR for the relay device (100), that is, for NCR-related functions, changes and additions to entities other than the NCR can be avoided. Furthermore, by applying a special scheduling method to terminals within the coverage of the relay device (100), it becomes possible to reduce inter-cell interference at an intermediate location between cells. Thus, it can be seen that the effect of preventing unnecessary throughput performance degradation and ensuring excellent service performance for the terminal at all times can be achieved.

[0137] Meanwhile, a channel estimation method according to one embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either individually or in combination. The program instructions recorded on the medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware devices described above may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

[0138] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above-described embodiments, and the technical concept of the present invention extends to the scope in which various modifications or alterations are possible by anyone with ordinary knowledge in the technical field to which the present invention belongs, without departing from the gist of the present invention as claimed in the following claims. Industrial applicability

[0139] According to the relay device and traffic offloading method of the present invention, in a Multi-TRP (Transmission / Reception Point) based NCJT (Non-Coherent Joint Transmission) environment, the number of layers between TRPs can be adaptively distributed by reflecting the actual performance of the channel. Since this overcomes the limitations of existing technology, it is an invention with industrial applicability, as it not only offers sufficient potential for the commercialization or business of the applied device rather than just the use of related technology, but is also practically and clearly implementable. Explanation of the symbols

[0140] 100: Relay device 110: Decision part 120: Control unit

Claims

Claim 1 A repeater device comprising: a memory including instructions; and a processor that, by executing the instructions, determines two or more candidate cells capable of sharing the coverage of the repeater device based on the reception strength of a Synchronization Signal Block (SSB) radiated from an adjacent cell, and when a specific candidate cell is selected according to a traffic comparison result using traffic-related information collected from the two or more candidate cells, forms the coverage of the repeater device as the coverage of the specific candidate cell. Claim 2 A relay device according to claim 1, wherein the two or more candidate cells include adjacent cells in which the SSB is received with a reception strength greater than or equal to a reference size, and the difference in reception strength of the SSB between cells is less than a threshold. Claim 3 A relay device according to claim 1, wherein the processor, when a first candidate cell and a second candidate cell exist and the reception strength of the SSB radiated from the first candidate cell is greater than that of the second candidate cell, performs an initial attachment to the first candidate cell to form the coverage of the relay device as the coverage of the first candidate cell. Claim 4 A relay device according to claim 3, wherein the processor collects traffic-related information from the first candidate cell upon initial attachment to the first candidate cell, and when a certain waiting time has elapsed after collecting the traffic-related information, if there is no terminal serviced by the first candidate cell within the coverage of the relay device, switches the attachment to the second candidate cell to collect the traffic-related information from the second candidate cell. Claim 5 A relay device according to claim 1, wherein the processor has a first candidate cell and a second candidate cell, and when the traffic comparison result shows that the traffic of the first candidate cell is less than the traffic of the second candidate cell by more than a threshold, the relay device is characterized by forming the coverage of the first candidate cell. Claim 6 In claim 5, the coverage of the relay device is characterized by applying a scheduling method of stacking PRBs (Physical Resource Blocks) along one direction in the frequency domain when forming the coverage of the first candidate cell, in a direction different from that of the scheduling method of the second candidate cell. Claim 7 A traffic offloading method performed in a repeater, characterized by comprising: a determination step of determining two or more candidate cells that can share the coverage of the repeater, based on the reception strength of a Synchronization Signal Block (SSB) radiated from an adjacent cell, such that the difference in reception strength of the SSB between the cells is less than a threshold value; and a control step of forming the coverage of the repeater into the coverage of the specific candidate cell when a specific candidate cell is selected according to a traffic comparison result using traffic-related information collected from the two or more candidate cells. Claim 8 A traffic offloading method according to claim 7, wherein the control step is characterized by performing an initial attachment to the first candidate cell when the receiving strength of the SSB radiated from the first candidate cell is greater than that of the second candidate cell, thereby forming the coverage of the relay device as the coverage of the first candidate cell. Claim 9 A traffic offloading method according to claim 8, wherein the control step collects traffic-related information from the first candidate cell upon initial attachment to the first candidate cell, and when a certain waiting time elapses after collecting the traffic-related information, if there is no terminal serviced by the first candidate cell within the coverage of the relay device, switches the attachment to the second candidate cell to collect the traffic-related information from the second candidate cell. Claim 10 A traffic offloading method according to claim 7, wherein the control step is characterized by forming the coverage of the relay device as the coverage of the first candidate cell when a first candidate cell and a second candidate cell exist, and the traffic comparison result shows that the traffic of the first candidate cell is less than the traffic of the second candidate cell by more than a threshold value. Claim 11 A traffic offloading method according to claim 10, wherein the coverage of the relay device is characterized by applying a scheduling method of stacking PRBs (Physical Resource Blocks) along one direction in the frequency domain when forming the coverage of the first candidate cell, in a direction different from that of the scheduling method of the second candidate cell. Claim 12 A computer program stored on a medium to execute the method of any one of claims 7 to 11, combined with hardware.

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