Downlink backhaul link scheduling method and system with dominant information indication in relay network

Abstract

The invention relates to the field of communication, in particular to a downlink backhaul link scheduling method and system with dominant information indication in a relay network. The method comprises the following steps: an IAB-Donor informs a selectable C-RNTI range of the range; whenever the UE accesses the IAB-Node, the IAB-Node allocates a C-RNTI to the accessed UE and reports the C-RNTI to the IAB-Donor; the IAB-Node regularly performs blind measurement on a PDCCH (Physical Downlink Control Channel) by using own C-RNTI to obtain a list of UE (User Equipment); the IAB-Node uses the C-RNTI corresponding to each UE in the list to obtain second data, and the content of the second data is data information sent to the corresponding UE in the list by the IAB-Donor; and the IAB-Node schedules the data information in the second data to the corresponding UE in the subsequent time slot. The transmission efficiency can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a downlink return link scheduling method and system of a relay network with explicit information indication. Background Art

[0002] Integrated Access and Backhaul (IAB) is one of the key technologies of the fifth generation mobile communications (5G). It integrates access and backhaul transmission functions and uses wireless backhaul links to enhance deployment flexibility, improve coverage and enhance network performance. Its main advantages are reflected in the following aspects.

[0003] 1) Wireless Backhaul: IAB does not rely on wired connections such as optical fiber links, but instead uses wireless communications such as millimeter wave or microwave links for backhaul transmission. The flexibility of this wireless backhaul is particularly useful in scenarios where it is difficult to deploy wired backhaul links.

[0004] 2) Flexible deployment: IAB enables base stations to be placed in locations that were previously impractical or cost-prohibitive, thereby enhancing deployment flexibility. This is particularly valuable in rural or remote areas where laying fiber or building traditional backhaul infrastructure is economically challenging.

[0005] 3) Coverage Extension: IAB is able to extend coverage to areas that were previously underserved or lacking network connectivity. By eliminating the need for separate backhaul infrastructure, base stations can be deployed in a more distributed manner, reaching locations with limited accessibility.

[0006] In the existing scheme, the schematic diagram of the IAB system with two-hop relay is as follows: Figure 1 As shown. Taking the downlink as an example, after the data information from the core network reaches the IAB-Donor (the termination node of the network-side backhaul link), it is forwarded to the UE (mobile terminal) via the IAB-Node (relay node), where the link between the IAB-Donor and the IAB-Node is the backhaul link, and the link between the IAB-Node and the UE is the access link. Figure 2As shown in the figure, it is a schematic diagram of the communication protocol stack, which builds GTP-U tunnels between UPF (user plane function) and IAB-Donor, and between IAB-Donor and IAB-Node; when the two tunnels are connected, UPF will assign an external IP to the UE. This external IP is the IP address inside the tunnel and is managed by the provider of mobile operation services; then, the UE can use this external IP to connect to the IAB-Node, from the IAB-Node through the F1-U protocol, through the GTP-U tunnel to the IAB-Donor, and then from the IAB-Donor through the NG-U protocol, through the GTP-U tunnel to the UPF, and then connect to the Internet through the UPF. The data encapsulation form of GTP-U transmitted on the backhaul link is as follows: Figure 3 As shown in the figure, since the tunnel terminates at the IAB-Node, only the external UDP and external IP can be compressed at the PDCP layer, and the GTP header, internal IP and internal TCP / UDP need to be transmitted intact on the wireless channel. Therefore, more wireless resources will be used for overhead transmission, reducing transmission efficiency and spectrum utilization. Summary of the invention

[0007] In view of the problems in the above existing solutions, the present invention proposes a new relay transmission solution:

[0008] The present invention provides a relay network system, comprising an IAB-Node and an IAB-Donor connected to each other, wherein the IAB-Donor is used to connect to a UPF, and the IAB-Node is used to connect to a UE; a GTP-U tunnel is not established between the IAB-Node and the IAB-Donor, and a GTP-U tunnel is established between the IAB-Donor and the UPF.

[0009] The present invention also provides a downlink backhaul link scheduling method with explicit information indication in a relay network. Based on the above system, the scheduling method includes the following steps:

[0010] S1: IAB-Donor informs IAB-Node of the range of optional C-RNTIs;

[0011] S2: Whenever a UE accesses the IAB-Node, the IAB-Node allocates a C-RNTI to the accessed UE according to the range of optional C-RNTIs;

[0012] S3: IAB-Node reports the C-RNTI allocated to the UE to IAB-Donor;

[0013] S4: The IAB-Node periodically performs blind testing on the PDCCH with its own C-RNTI to detect whether the first scheduling indication information given to it by the IAB-Donor exists; if not, no subsequent steps are performed; if so, subsequent steps are performed;

[0014] S5: The IAB-Node obtains first data from the PDSCH according to the first scheduling indication information, where the content of the first data is a list of UEs, where all UEs in the list are in the current time slot and have data information from the IAB-Donor;

[0015] The IAB-Node uses the C-RNTI corresponding to each UE in the list to perform blind testing on the PDCCH respectively, obtains the second scheduling indication information given by the IAB-Donor to itself, and then obtains the second data from the PDSCH according to the second scheduling indication information, where the content of the second data is the data information sent by the IAB-Donor to the corresponding UE in the list;

[0016] S6: The IAB-Node schedules the data information in the second data to the corresponding UE in a subsequent time slot.

[0017] Preferably, the specific process of the IAB-Node allocating a C-RNTI to the accessed UE according to the optional C-RNTI range is:

[0018] S2.1: Receive the random access preamble Msg1 sent by the UE;

[0019] S2.2: Send a random access response Msg2 to the UE, where the random access response Msg2 includes the TC-RNTI allocated to the UE;

[0020] S2.3: Receive the connection request Msg3 sent by the UE and encrypted by TC-RNTI;

[0021] S2.4: Send a contention resolution message Msg4 to the UE and upgrade the TC-RNTI to a C-RNTI, that is, allocate a C-RNTI to the UE, and the allocated C-RNTI is obtained from the range of optional C-RNTIs.

[0022] The present invention also provides a relay network system, including an IAB-Node and an IAB-Donor connected to each other, wherein the IAB-Donor is used to connect to a UPF, and the IAB-Node is used to connect to a UE; no GTP-U tunnel is established between the IAB-Node and the IAB-Donor, and a GTP-U tunnel is established between the IAB-Donor and the UPF; and scheduling is performed using the above method.

[0023] Beneficial effects:

[0024] 1. The relay network system of the present invention does not establish a GTP-U tunnel between the IAB-Node and the IAB-Donor. Therefore, the external IP, external UDP and GTP headers of the data packets transmitted on the return link do not exist. The PDCP layer on the return link can directly compress the internal IP and internal TCP / UDP packet headers, thereby effectively reducing the amount of data transmitted on the wireless return link.

[0025] 2. In the process of extracting data information to be transmitted to the UE, the IAB-Node adopts the method of twice PDCCH detection. Compared with directly using the C-RNTI of all UEs under its jurisdiction for blind testing, it can greatly improve the transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of an IAB system with two hop relays in the prior art;

[0027] Figure 2 It is a schematic diagram of the IAB communication protocol stack of two-hop relay in the prior art;

[0028] Figure 3 The format of the datagram transmitted on the return link of two relays in the prior art;

[0029] Figure 4 Schematic diagram of the IAB communication protocol stack in an embodiment of the present invention;

[0030] Figure 5 A schematic diagram of scheduling indication information on a PDCCH and scheduling data on a PDSCH in an embodiment of the present invention;

[0031] Figure 6 A schematic diagram of a resource scheduling process for a downlink backhaul link in an embodiment of the present invention;

[0032] Figure 7 The figure is a schematic diagram of a process in which a UE randomly accesses and obtains C-RNTI allocation in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] A relay network system includes an IAB-Node and an IAB-Donor connected to each other, wherein the IAB-Donor is used to connect to a UPF, and the IAB-Node is used to connect to a UE; a GTP-U tunnel is not established between the IAB-Node and the IAB-Donor, and a GTP-U tunnel is established between the IAB-Donor and the UPF.

[0035] A downlink backhaul link scheduling method with explicit information indication in a relay network is provided, based on the above relay network system, and the scheduling method comprises the following steps:

[0036] S1: IAB-Donor informs IAB-Node of the range of optional C-RNTIs;

[0037] S2: Whenever a UE accesses the IAB-Node, the IAB-Node allocates a C-RNTI to the accessed UE according to the range of optional C-RNTIs;

[0038] In this embodiment, the specific process of the IAB-Node allocating a C-RNTI to the accessed UE according to the optional C-RNTI range is as follows:

[0039] S2.1: Receive the random access preamble Msg1 sent by the UE;

[0040] S2.2: Send a random access response Msg2 to the UE, where the random access response Msg2 includes the TC-RNTI allocated to the UE;

[0041] S2.3: Receive the connection request Msg3 sent by the UE and encrypted by TC-RNTI;

[0042] S2.4: Send a contention resolution message Msg4 to the UE and upgrade the TC-RNTI to a C-RNTI, that is, allocate a C-RNTI to the UE, and the allocated C-RNTI is obtained from the range of optional C-RNTIs.

[0043] S3: IAB-Node reports the C-RNTI allocated to the UE to IAB-Donor;

[0044] S4: The IAB-Node periodically performs blind testing on the PDCCH with its own C-RNTI to detect whether the first scheduling indication information given to it by the IAB-Donor exists; if not, no subsequent steps are performed; if so, subsequent steps are performed;

[0045] S5: The IAB-Node obtains first data from the PDSCH according to the first scheduling indication information, where the content of the first data is a list of UEs, where all UEs in the list are in the current time slot and have data information from the IAB-Donor;

[0046] The IAB-Node uses the C-RNTI corresponding to each UE in the list to perform blind testing on the PDCCH respectively, obtains the second scheduling indication information given by the IAB-Donor to itself, and then obtains the second data from the PDSCH according to the second scheduling indication information, where the content of the second data is the data information sent by the IAB-Donor to the corresponding UE in the list;

[0047] S6: The IAB-Node schedules the data information in the second data to the corresponding UE in a subsequent time slot.

[0048] The principles and technical details of the present invention are described in more detail below:

[0049] This patent proposes a new relay transmission solution, such as Figure 4 As shown in the figure, the tunnel termination node is not the IAB-Node that directly communicates with the UE, but the tunnel is terminated to the IAB-Donor. It is necessary to add certain mechanisms and complexity to the IAB-Donor to improve the transmission efficiency of the wireless link. Figure 3 It can be seen that at this time, the external IP, external UDP and GTP headers of the data packets transmitted on the backhaul link no longer exist. The PDCP layer on the backhaul link can directly compress the internal IP and internal TCP / UDP packet headers, thereby effectively reducing the amount of data transmitted on the wireless backhaul link.

[0050] Table 1 Comparison between the new solution and the existing solution

[0051] Compare Content Existing solutions New Solution Tunnel endpoint IAB-Node IAB- Donor C-RNTI allocation corresponding to UE IAB-Node Allocation IAB-Node assigns and notifies IAB--Donor

[0052] The GTP-U protocol terminates at the IAB-Donor, which means that the IAB-Donor needs to know some information about the UE under the jurisdiction of the IAB-Node, that is, the IAB-Node needs to inform the IAB-Donor of the UE's C-RNTI (Radio Network Temporary Identity) information. In this way, in the information transmission of the return link, the header compression function of the PDCP layer can be fully utilized, and the packet header of "internal IP, internal TCP / UDP" can be compressed, thereby saving precious wireless transmission resources. In a further implementation, the following resource scheduling method can be executed on the return link:

[0053] On the PDCCH (Physical Downlink Control Channel) of the backhaul link, the IAB-Donor sends the following two scheduling indication messages, indicating that there are two data messages carried on the PDSCH (Physical Downlink Shared Channel) in this scheduling time slot.

[0054] (1) Data information scheduled by IAB-Donor to IAB-Node, which is used to indicate which UE data information is transferred from IAB-Donor to IAB-Node in this time slot.

[0055] (2) The data information scheduled by the IAB-Donor to the UE is first received by the IAB-Node, so that the IAB-Node can make reasonable arrangements independently in the subsequent scheduling time slot and further transmit the data information to the corresponding UE.

[0056] like Figure 6 As shown, here we specifically describe the working process of IAB-Node as follows.

[0057] (1) The IAB-Node performs blind detection on the PDCCH using its own C-RNTI to obtain scheduling indication information from the IAB-Donor in the current time slot;

[0058] (2) If the IAB-Node does not detect any scheduling indication information for itself, it enters sleep mode and skips steps (3) and (4).

[0059] (3) If the IAB-Node detects the scheduling indication information, it will perform operations such as demodulation and decoding on the corresponding PDSCH according to the indication to obtain the data content. This information is used to inform the IAB-Node which UEs managed by the IAB-Node have downlink data transmitted by the IAB-Donor to the IAB-Node in this time slot;

[0060] (4) The IAB-Node knows that one or more UEs under its jurisdiction have data content transmitted from the IAB-Donor to the IAB-Node in this time slot. It uses the indicated C-RNTI of each UE to perform blind detection on the PDCCH to obtain the scheduling indication, and then extracts the downlink data information for each UE in the PDSCH;

[0061] (5) The IAB-Node can autonomously schedule the downlink data information of each UE to the corresponding UE in the subsequent time slot. This belongs to resource scheduling on the access link and follows the existing operating procedures.

[0062] It should be emphasized that the IAB-Node adopts the method of PDCCH detection twice in the process of extracting data information to be transmitted to the UE. This is because if the number of UEs under the jurisdiction of the IAB-Node is large, for example, 100, then the IAB-Node must use the C-RNTI of these 100 UEs to perform blind detection operations in the PDCCH without receiving explicit indication information from the IAB-Donor. The processing burden of the IAB-Node caused by this is huge; therefore, a two-step method is adopted to let the IAB-Node know which UEs have downlink data transmission first, and then only use the C-RNTI of a limited number of UEs to perform blind detection, which can achieve a compromise between processing complexity and return link data compression. If in the same time slot, data of multiple UEs is transmitted from the IAB-Donor to the IAB-Node, then the IAB-Donor can notify the IAB-Node that there are data information of multiple UEs in this time slot, and indicate the information of multiple UEs together, so that the transmission efficiency will be better. The schematic diagram of the position of PDCCH and PDSCH on the time-frequency resource block is shown in the figure. Figure 5 The control information extracted from the PDCCH includes the time-frequency position of the corresponding PDSCH and the modulation, channel coding and multi-antenna transmission parameters used for data transmission in the PDSCH, so as to facilitate the extraction of data information from the PDSCH.

[0063] Different from the existing solution, the C-RNTI of the UE under the jurisdiction of the IAB-Node is allocated and managed by the IAB-Node, and the IAB-Donor does not need to know any information of the UE under the jurisdiction of the IAB-Node; in the new solution, the IAB-Node needs to inform the IAB-Donor of the C-RNTI of the UE in order to perform the downlink resource scheduling operation described above. Figure 7 As shown, the specific signaling interaction process is as follows:

[0064] (0) The IAB-Donor informs the IAB-Node of the range of optional C-RNTIs, that is, sets up different C-RNTI pools for each IAB-Node under the IAB-Donor to prevent conflicts in the C-RNTIs reported by the IAB-Node to the IAB-Donor in step (5).

[0065] (1) The UE sends a random access preamble Msg1. It is a random sequence obtained based on the random access-related parameter configuration broadcast by the IAB-Node in the system message, and the RA-RNTI (Random Access-Radio Network Temporary Identity) is calculated based on the time-frequency resources when sending Msg1. After that, the UE starts to monitor the PDCCH.

[0066] (2) IAB-Node sends a random access response Msg2 (Random Access Response, RAR). The base station will also calculate the RA-RNTI based on the time-frequency resources of the received Msg1 and use it to scramble the PDCCH. The UE uses the local RA-RNTI to blindly detect the PDCCH to obtain the PDSCH scheduling information sent by the base station, and receives the random access response Msg2 on the corresponding PDSCH resource, which contains the TC-RNTI (Temporary Cell-Radio Network Temporary Identity) assigned to the UE.

[0067] (3) The UE sends a connection request Msg3. The UE sends the TC-RNTI-encrypted Msg3 on the physical uplink shared channel (PUSCH) according to the resource information of the uplink grant indication in Msg2.

[0068] (4) IAB-Node sends a contention resolution message Msg4. If multiple terminals initiate random access at the same random access opportunity using the same preamble and time-frequency resources, contention will occur. Msg4 is to resolve this problem. If there is no contention among multiple UEs, contention resolution is completed, random access is successful, and TC-RNTI is upgraded to C-RNTI.

[0069] (5) The IAB-Node informs the IAB-Donor of the C-RNTI allocated to the UE.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A relay network system, comprising an IAB-Node and an IAB-Donor connected to each other, wherein the IAB-Donor is used to connect to a UPF, and the IAB-Node is used to connect to a UE; characterized in that: No GTP-U tunnel is established between the IAB-Node and the IAB-Donor, and a GTP-U tunnel is established between the IAB-Donor and the UPF.

2. A method for scheduling a downlink backhaul link in a relay network with explicit information indication, based on the system of claim 1, characterized in that: The scheduling method includes the following steps: S1: IAB-Donor informs IAB-Node of the range of optional C-RNTIs; S2: Whenever a UE accesses the IAB-Node, the IAB-Node allocates a C-RNTI to the accessed UE according to the range of optional C-RNTIs; S3: IAB-Node reports the C-RNTI allocated to the UE to IAB-Donor; S4: The IAB-Node periodically performs blind testing on the PDCCH with its own C-RNTI to detect whether the first scheduling indication information given to it by the IAB-Donor exists; if not, no subsequent steps are performed; if so, subsequent steps are performed; S5: The IAB-Node obtains first data from the PDSCH according to the first scheduling indication information, where the content of the first data is a list of UEs, where all UEs in the list are in the current time slot and have data information from the IAB-Donor; The IAB-Node uses the C-RNTI corresponding to each UE in the list to perform blind testing on the PDCCH respectively, obtains the second scheduling indication information given by the IAB-Donor to itself, and then obtains the second data from the PDSCH according to the second scheduling indication information, where the content of the second data is the data information sent by the IAB-Donor to the corresponding UE in the list; S6: The IAB-Node schedules the data information in the second data to the corresponding UE in a subsequent time slot.

3. A method for scheduling a downlink backhaul link in a relay network with explicit information indication according to claim 2, characterized in that: The specific process of IAB-Node allocating C-RNTI to the accessed UE according to the optional C-RNTI range is as follows: S2.1: Receive the random access preamble Msg1 sent by the UE; S2.2: Send a random access response Msg2 to the UE, where the random access response Msg2 includes the TC-RNTI allocated to the UE; S2.3: Receive the connection request Msg3 sent by the UE and encrypted by TC-RNTI; S2.4: Send a contention resolution message Msg4 to the UE and upgrade the TC-RNTI to a C-RNTI, that is, allocate a C-RNTI to the UE, and the allocated C-RNTI is obtained from the range of optional C-RNTIs.

4. A relay network system, comprising an IAB-Node and an IAB-Donor connected to each other, wherein the IAB-Donor is used to connect to a UPF, and the IAB-Node is used to connect to a UE; no GTP-U tunnel is established between the IAB-Node and the IAB-Donor, and a GTP-U tunnel is established between the IAB-Donor and the UPF; characterized in that: The scheduling is performed using the method described in any one of claims 2 to 3.

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