Adaptive feedback method, telecommunication system, base station and user equipment

Abstract

An adaptive feedback method, a telecommunication system, a base station and a user equipment (UE) for a telecommunication system comprising network nodes to provide multimedia broadcast multicast services (MBMS) to one or more UEs. A multicast broadcast single frequency network (MBSFN) transmission is performed to provide one or more MBMS services, a plurality of transport blocks (TBs) and a plurality of hybrid automatic repeat request (HARQ) parameters are transmitted. A first UE transmits a feedback message based on the HARQ parameters.

Description

Technical Field

[0001] This invention relates to wireless communication, and more particularly to a multimedia broadcast / multicast service (MBMS) system. Background Technology

[0002] MBMS is a point-to-multipoint interface designed for efficient delivery of broadcast and multicast services in 3GPP cellular networks. MBMS provides multicast services within a single cell using Single Cell Point to Multipoint (SC-PTM) transmission and broadcast services across a group of cells using Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) transmission. SC-PTM uses the same LTE downlink shared channel and subframe structure for transmission; while MBSFN defines new channels and has a different subframe structure than regular subframe LTE to ensure transmission across a group of cells. Given the lack of an effective feedback mechanism in MBMS systems to ensure quality of service (QoS), potential solutions are needed. A summary of the proposed embodiments is given below. Summary of the Invention

[0003] An adaptive feedback method is provided, which can be implemented in a telecommunications system comprising at least network nodes and multiple user equipments (UEs) to provide multimedia broadcast multicast service (MBMS). Network nodes, typically referred to as base stations, can be enodeB, gNB, or any upper-layer network unit in a 5G NR system.

[0004] MBMS service is provided by a Multicast-Broadcast Single-Frequency Network (MBSFN) transmission that repeats within a cycle. In MBSFN transmission, multiple transport blocks (TBs) and multiple Hybrid Automatic Repeat Request (HARQ) parameters are transmitted from network nodes. Upon receiving the HARQ parameters, the first UE within the MBMS service coverage area can conditionally send a feedback message based on the HARQ parameters.

[0005] Examples of HARQ parameters include one or more of the following: modulation and coding scheme (MCS), new data indicator (NDI), redundancy version (RV), process identifier (PID), feedback time-domain indicator for allocating feedback resources in the time domain, and feedback frequency-domain indicator for allocating feedback resources in the frequency domain. Some HARQ parameters are generally known in existing unicast systems.

[0006] Feedback resources generally refer to the channels, configurations, and parameters defined by various protocols required for a telecommunications system to complete transmission. Feedback resources in the time domain define the timing for sending feedback messages. Feedback resources in the frequency domain may include channel information or bandwidth information that can be used for feedback message transmission. For example, the feedback time domain indicator may include pre-configured or fixed values. When a feedback message needs to be sent, the first UE determines the time slot based on the feedback time domain indicator and then sends the feedback message in the time slot after receiving the last TB of the MBMS service.

[0007] Implementations of several possible methods are provided. HARQ parameters can be transmitted in the same or different ways. One HARQ parameter can be embedded in the Multicast Control Channel (MCCH) and transmitted through the Radio Resource Control (RRC) plane. Another HARQ parameter can be embedded in the Multicast Channel (MCH) Scheduling Information (MSI) and transmitted through the Media Access Control (MAC) Control Element (CE). Yet another HARQ parameter can be embedded in the Downlink Control Information (DCI) located in the control area of ​​the MBSFN subframe and then sent to the UE.

[0008] Alternative methods for transmitting HARQ parameters are conditionally selectable. For example, the manner in which the first HARQ parameter is transmitted can depend on the frequency of its variation. In one case, if the frequency of variation of the first HARQ parameter exceeds a first threshold, a DCI is used to carry and transmit the first HARQ parameter. In another case, if the frequency of variation of the first HARQ parameter is below a second threshold, an MCCH is used to carry the first HARQ parameter. Alternatively, if the frequency of variation of the first HARQ parameter is below a third threshold, an MSI is used to carry and transmit the first HARQ parameter. The actual values ​​of the first, second, and third thresholds can be determined experimentally or empirically, and therefore will not be specifically described here.

[0009] In this embodiment of feedback message transmission, only negative acknowledgment (NACK) messages are transmitted, not ACK messages. A NACK message is sent when the first UE fails to decode one or more TBs. Conversely, no ACK message is sent when the first UE successfully decodes all TBs. This way, only one feedback resource is needed to send NACK messages. The feedback resource can be pre-allocated by the network node and then shared by multiple UEs for NACK transmission. Since the network node does not need to distinguish the owner of the NACK message, a single feedback resource can be reused by multiple UEs. For example, all UEs or a subset of UEs can share a single feedback resource or a pool of feedback resources for NACK message transmission.

[0010] In another scenario, an ACK message is also sent. An ACK message is only sent to the network node when the first UE successfully decodes all TBs within a predetermined period. In one scenario, ACK and NACK feedback resources are allocated separately for each UE to send ACK and NACK messages respectively. In another scenario, ACK / NACK feedback resources are shared. ACK feedback resources are allocated and shared by multiple UEs to send ACK messages, and NACK feedback resources are allocated and shared by multiple UEs to send NACK messages.

[0011] An embodiment of a retransmission mechanism is proposed. The retransmission function can be conditionally enabled or disabled based on retransmission criteria. If enabled, the network node responds to a NACK message from the first UE by retransmitting one or more TBs corresponding to the NACK message. The retransmission criteria may include a service priority corresponding to the MBMS service, and retransmission is only enabled when the service priority exceeds a first threshold. As an example of how to determine service priority, one or more Quality of Service (QoS) Flow Identifiers (QFIs) corresponding to the MBMS service can be obtained on the network node side; these QFIs can be used as a reference to determine the service priority. The first threshold may be experimental or empirical, therefore no specific or limited value is specified here.

[0012] Various embodiments of MBMS service periodicity are provided. In MBSFN transmission, one or more MBMS services can be provided within a predetermined period. Within the predetermined period, an ACK message can only be sent if all TBs have been successfully decoded. Furthermore, a NACK message can be sent if at least one TB fails to decode within the predetermined period. Embodiments of the predetermined period can be one of the following values: MCH Service Period (MSP), Common Subframe Allocation Period, MCCH Repetition Period, MCCH Modification Period, or a custom period. The enlistment period value is essentially calculated in frames. Each TB is scheduled by a Transmission Time Interval (TTI).

[0013] In another embodiment, the feedback mechanism can be conditionally enabled or disabled. A feedback enable signal can be generated based on a first condition and sent to the first UE. The first UE can only send a feedback message when the feedback enable signal enables the feedback mechanism.

[0014] Similar to HARQ parameters, the feedback enable signal can be transmitted in various formats. For example, the feedback enable signal can be carried by a System Information Block 2 (SIB2) message, a SIB13 message, a signal via the MCCH, a signal via the MAC CE, or a signal via the DCI. It is also preferable to implement the feedback enable signal as part of the HARQ parameters transmitted in the above method.

[0015] The primary criterion for determining whether to enable feedback mechanisms may depend on the importance of the service being provided. Typically, video or audio streaming services are not mission-critical and can tolerate a certain level of error. For such services, feedback mechanisms can be disabled. On the other hand, some services are mission-critical and require accurate data transmission over the MBSFN network, such as emergency broadcasts or vehicle-to-everything (V2X) applications. Feedback mechanisms can be selectively enabled for mission-critical services or applications.

[0016] The implementation of the adaptive feedback method involves at least a network node and a UE. Therefore, an embodiment of a telecommunications system implementing the adaptive feedback method is also provided, including at least one network node and one or more UEs. Furthermore, embodiments of a base station and a UE implementing the adaptive feedback method are also provided. Since the characteristics of the telecommunications system, base station, network node, and UE have already been described in the preceding paragraphs, detailed embodiments will not be repeated here.

[0017] The embodiments are described in more detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The invention can be more fully understood by referring to the following detailed description and embodiments, in which:

[0019] Figure 1a A flowchart showing an embodiment of the adaptive feedback method is displayed;

[0020] Figure 1b Display based on Figure 1a An example of a downlink (DL) hybrid automatic repeat request (HARQ) process;

[0021] Figure 2 A flowchart showing the method selection according to one embodiment of the adaptive feedback method is displayed;

[0022] Figure 3 Implementation examples showing the determined feedback mode;

[0023] Figure 4 This diagram illustrates the retransmission activation flowchart according to an embodiment of the present invention.

[0024] Figure 5 This illustrates an example of MSBFN transmission;

[0025] Figure 6 A flowchart showing the feedback enabling mechanism according to an embodiment of the present invention is displayed;

[0026] Figure 7 An embodiment of a telecommunications system 700 providing MBMS services is shown; and

[0027] Figure 8 This application illustrates an embodiment of a user equipment (UE) 800. Detailed Implementation

[0028] The following description represents the preferred mode for carrying out the invention. This description is intended to illustrate the general principles of the invention and should not be construed as limiting. The scope of the invention is best determined by referring to the appended claims.

[0029] MBMS is not discussed in NR. In this specification, we use the scheduling and transmission mechanisms of MBMS in LTE as a benchmark, combined with the new features in NR. Reliability is one of the requirements for development in Broadcast / Multicast Services (MBMS). Typically, the level of reliability varies depending on the user application. This disclosure proposes an uplink feedback mechanism as a solution to improve MBMS reliability.

[0030] Figure 1aThis diagram shows a flowchart of an embodiment of the adaptive feedback method. The adaptive feedback method can be implemented in a telecommunications system comprising at least network nodes and multiple user equipments (UEs) to provide Multimedia Broadcast Multicast Service (MBMS). Network nodes, typically referred to as base stations, can be enodeBs, gNBs, or any upper-level network unit in a 5G NR system. The most generalized steps of the adaptive feedback method can be summarized into three steps. In step 101, MBSFN transmission is initialized. MBSFN transmission refers to the transmission of multiple transport blocks (TBs) from the network node to periodically provide one or more MBMS services. In step 103, multiple hybrid automatic repeat request (HARQ) parameters are sent from the network node. HARQ parameter transmission can utilize various radio resources described below. HARQ parameter transmission can be periodic, depending on various QoS parameters of the corresponding MBMS service, or triggered by the UEs as needed. Embodiments of HARQ parameter transmission can vary in any feasible manner, as long as the HARQ parameters are effectively transmitted. In step 105, the UE conditionally sends a feedback message based on the HARQ parameters. Various embodiments regarding feedback transmission will be described below.

[0031] Figure 1b Display based on Figure 1a This is an embodiment of the downlink (DL) Hybrid Automatic Repeat Request (HARQ) procedure. The HARQ procedure is used by the sender 110 to transmit consecutive data blocks to the receiver 120. Generally, in the HARQ procedure, the sender 110 is a network node, such as a base station (BS), eNodeB (eNB), or gNB. The receiver 120 is referred to as the user equipment (UE) under the MBSFN network coverage, also known as a mobile device.

[0032] In step 102, the sender 110 initializes a new DL allocation. Transport block (TB) DATA1 is transmitted. For example, process ID, New Data Indicator (NDI), Redundancy Version (RV), and control information for feedback resources (timing and frequency) are incorporated into the downlink control information (DCI) message. In step 104, if the receiver 120 successfully decodes the received TB data 1, it sends an ACK message to the sender 110. In this case, in step 106, the sender 110 continues to send the next TB data 2, along with the same process ID and corresponding control information, to the receiver 120. If the receiver fails to receive and / or decode TB data DATA2, in step 108, the receiver 120 sends a NACK message to the sender 110. In step 112, a retransmission is triggered, wherein the sending end 110 retransmits the same TB data 2, the same process ID, the switched NDI (toggled NDI) (from 0 to 1), and the new RV according to the feedback resources allocated by the sending end 110. MBMS service is provided periodically through methods such as Multicast Broadcast Single Frequency Network (MBSFN) transmission. After receiving the control information sent in step 110, the receiving end 120 under the MBMS service coverage may conditionally send feedback messages based on the control information, such as in steps 104, 108, and 114.

[0033] The aforementioned control information, hereinafter referred to as HARQ parameters, typically indicates the status, values, modes, resources, and configurations defined by various protocols during transmission. Examples may include, but are not limited to, the following parameters: modulation coding scheme (MCS), new data indicator (NDI), redundancy version (RV), process identifier (PID), feedback time domain indicator for allocating feedback resources in the time domain, and feedback frequency domain indicator for allocating feedback resources in the frequency domain. Some HARQ parameters are generally known in existing unicast systems. Feedback resources typically refer to the various protocol-defined channels, configurations, and parameters required for a telecommunications system to complete transmission. Feedback resources in the time domain may include time slot information, such as the time gap defining the timing for sending feedback messages. Feedback resources in the frequency domain may include channel information or bandwidth part information that can be used for feedback message transmission. For example, the feedback time domain indicator may include pre-configured values ​​or fixed values. When a feedback message is to be sent, the first UE determines the time interval according to the feedback time domain indication, and then sends the feedback message in the time interval after receiving the last TB of the MBMS service.

[0034] There are several methods for a User Equipment (UE) to obtain MBMS control information (i.e., HARQ parameters) from the network. The first method is through system information block No. 13 (SIB13), from which the UE obtains the Multicast Control Channel (MCCH), which carries MBMS control information associated with one or more MBSFN areas. An example of an information element (IE) from SIB13 is shown below.

[0035]

[0036]

[0037] For example, in SIB13 IE, the subframe allocated for the MCCH message is carried by IE MBSFN-AreaInfoList-r9. The MCCH modification cycle is carried by IE MBMS-NotificationConfig.

[0038] Secondly, the UE can also decode the messages carried by the MCCH to obtain various parameters, such as Common Subframe Allocation (CSA), MCH Subframe Allocation (MSA), and MCH Scheduling Period (MSP). The following shows an example of the MBSFNAreaConfiguration message, which is carried by the MCCH.

[0039]

[0040] The Common Signature (CSA), carried by IE commonSF-Alloc-r9, indicates the common pattern of subframes occupied by all MCHs within the same MBSFN area. This common pattern repeats periodically according to the CSA period defined by IE commonSF-AllocPeriod-r9. The MSA, carried by IE pmch-InfoList-r9, defines the actual MSA for each multicast channel (MCH) by the CSA and the CSA period carried by the MCCH. The tail portion of the MSA indicates the last subframe of the MCH within the CSA period. The MSP, carried by IE pmch-InfoList-r9, is configurable according to the MCH.

[0041] The third way the UE receives MBMS control information is through MCH scheduling information (MSI) in the form of MAC control elements (CEs). During each MSP of the MCH, the eNB performs MAC multiplexing on different multicast traffic channels (MTCHs) and optionally transmits MCCHs on the MCH. The MSI is provided by the MCH to indicate which subframes are used for each MTCH during the MSP and to indicate whether the transmission of the MTCH has been scheduled or suspended by the eNB.

[0042] As described, each HARQ parameter can be selectively carried by the same or different methods, thus presenting possible implementations that vary exponentially.

[0043] The method for transmitting HARQ parameters is conditionally selectable. Figure 2This diagram shows a flowchart of method selection according to one embodiment of the adaptive feedback method. In step 201, conditions for determining the HARQ parameters are determined. Different conditions may lead to different processes. For case 1, the step proceeds to step 205; for case 2, it proceeds to step 207; and for case 3, it proceeds to step 209. For example, the way the HARQ parameters are transmitted may depend on the frequency of HARQ parameter changes. In step 203, if the frequency of HARQ parameter changes exceeds a first threshold, then in step 205, the HARQ parameters are carried and transmitted using DCI.

[0044] Similarly, if step 203 matches case 2, for example, the frequency of HARQ parameter changes is less than the second threshold, then step 207 continues. MCCH is used to transmit HARQ parameters in step 207.

[0045] Similarly, when step 203 matches case 3, for example, if the frequency of change of the first HARQ parameter is lower than the third threshold, the process proceeds to step 209. The MSI is therefore used in step 209 to carry and transmit the first HARQ parameter. The actual values ​​of the first, second, and third thresholds can be experimentally or empirically related. The conditional checks of the HARQ parameters can be based on many other factors, not limited to frequency or value changes.

[0046] A simplified feedback mechanism is proposed to improve the efficiency of MBSFN transmission. In some types of MBMS service provision, acknowledgment (ACK) messages are not required, but negative-acknowledgment (NACK) messages may be necessary. A NACK message is sent when the first UE fails to decode one or more TBs. Conversely, no ACK message is sent when the first UE successfully decodes all TBs. This requires only one feedback resource to send the NACK message. Since the network node does not need to distinguish the source of the NACK message, a single feedback resource can be reused by multiple UEs. For example, the feedback resource can be pre-allocated by the network node and then shared by all UEs or a subset of the UEs for NACK message transmission.

[0047] In some other types of MBMS services, ACK messages may also be required. An ACK message is sent only when the first UE successfully decodes all TBs within a predetermined period. In one scenario, each UE is allocated separate ACK feedback resources and separate NACK feedback resources to send ACK and NACK messages respectively. In another scenario, if network nodes do not need to distinguish the source of ACK / NACK messages, ACK / NACK resources can be shared. For example, ACK feedback resources are allocated and shared by all UEs or a subset of UEs for ACK message transmission; similarly, NACK feedback resources are allocated and shared by all UEs or a subset of UEs for NACK message transmission.

[0048] A mechanism may be needed to determine whether to send an ACK message. Figure 3 An embodiment showing the feedback mode determination is provided. In step 301, a conditional checking mechanism is provided to determine whether to send an ACK message. Case 1 proceeds to step 303, where various conditions can be determined as the basis for enabling or disabling ACK transmission. For example, the conditions may be related to QoS requirements or predetermined based on the service type at the upper layer. In case 2, step 305 is processed, where only NACK is required for a certain service or condition. Instead, step 307 is processed to send ACK and NACK messages.

[0049] On the network node side, the decision to retransmit is also considered. Figure 4 This diagram illustrates a retransmission activation flowchart according to an embodiment of the present invention. In step 401, the retransmission function can be conditionally enabled or disabled based on a retransmission criterion. In step 403, the retransmission criterion is checked. The retransmission criterion may include a service priority corresponding to the MBMS service, and retransmission is only enabled when the service priority exceeds a first threshold. As an example of how to determine service priority, one or more Quality of Service (QoS) flow IDs (QFIs) corresponding to the MBMS service can be obtained on the network node side, and these QFIs can be used as a reference to determine the service priority. The first threshold may be experimental or empirical, so no actual value is specified or limited here. In case 1, the process proceeds to step 405, where retransmission is enabled. In that case, the network node retransmits one or more TBs as necessary, for example, upon receiving a NACK message. Conversely, the process proceeds to step 407, where no retransmission is performed under any circumstances.

[0050] Figure 5This illustrates an example of MBSFN scheduling. Multiple downlink frames are transmitted consecutively, with each 16 frames referred to as a Common Subframe Allocation (CSA) period 540. Each frame 502 comprises 10 subframes 504, which are temporally equivalent to 20 time slots, as known in 5G standards. A subset of the downlink subframes 504 in radio frame 402 can be configured as MBSFN subframes by higher layers to carry MBMS service TBs. Each MBMS service may include multiple TBs transmitted within an MCH service period (MSP). Various embodiments of MBMS service periods are provided. In MBSFN transmission, one or more MBMS services can be provided within a predetermined period. Figure 4 The following explanation uses three services as examples. Services 1 and 3 can have 16-frame MSPs, such as MSP1 560. Service 2 can have 32-frame MSPs, such as MSP2 570. In each CSA cycle 540, TBs are transmitted in MCH1 510 for Service 1, MCH2 520 for Service 2, and MCH3 530 for Service 3.

[0051] During a predetermined period, an ACK message can only be sent if all TBs have been successfully decoded. Additionally, a NACK message can be sent if at least one TB fails to decode during the predetermined period. Examples of predetermined periods can be one of the following values: MSP 560 / 570, CSA period 540, MCCH repetition period 540, MCCH modification period 550, or a custom period (MSP). The enlisted period value is essentially calculated in frames.

[0052] In one embodiment, the MSP is used as a predetermined period to determine the conditions for sending ACK / NACK messages. After decoding all TBs on MCH1 510, MCH2 520, and MCH3 530 during the corresponding MSPs MSP1 560 and MSP2 570, the UE sends a feedback message based on an AND operation of all decoding results for the TBs. Assume that MSP1 560 is 16 frames for services 1 and 3, and MSP2 570 is 32 frames for service 2. During MSP1 560, there are 11 MBSFN subframes (TBs) in MCH1 510, 2 MBSFN subframes in MCH2 520 during MSP2 570, and 4 MBSFN subframes in MCH3 530 during MSP1 560. On MCH1 510, if decoding of any of the 11 TBs fails, the UE sends a NACK message. The same procedure is performed for MCH2 520 and MCH3 530. If all TBs within the corresponding MSPs of the three services are correctly decoded, the UE can conditionally send an ACK message or send nothing, such as... Figure 3 As described in step 303.

[0053] Other possible embodiments are provided by replacing the CSA period 540 (16 frames), MCCH repetition period 550 (based on mcch-RepetitionPeriod-r9 IE, which can be 32, 64, 128, or 256 frames), and MCCH modification period 580 (based on mcch-ModificationPeriod-r9 IE, which can be 512 or 1024 frames) with a predetermined period. The predetermined period can also be a period customized according to user requirements.

[0054] In a further embodiment, the feedback mechanism may be conditionally enabled or disabled. Figure 6A flowchart illustrating a feedback enabling mechanism according to an embodiment of the present invention is shown. In step 602, a process is initialized to determine whether the feedback mechanism is enabled. In step 604, a condition is checked. If condition 1 is met, then proceed to step 606. In step 606, the feedback mechanism is enabled. For example, a feedback enablement signal can be generated based on this condition and sent to the UE, instructing the UE to send a feedback message when the feedback mechanism is enabled. On the other hand, if condition 2 is met, the process proceeds to step 608, where the feedback mechanism is not required. In step 608, a feedback enablement signal can be generated to carry an instruction to disable the feedback mechanism, causing the UE to stop sending feedback messages upon receiving the feedback enablement signal. In practice, the actual conditions or circumstances checked in step 604 can depend on service QoS requirements, user customizations, or any factors related to performance and efficiency. This embodiment does not limit the implementation of step 604.

[0055] Similar to HARQ parameters, the feedback enable signal can be transmitted in various formats. For example, the feedback enable signal can be carried by a System Information Block 2 (SIB2) message, a SIB13 message, a signal via the MCCH, a signal via the MAC CE, or a signal via the DCI. It is also preferable to implement the feedback enable signal as part of the HARQ parameters transmitted in the above method.

[0056] The primary criterion for determining whether to enable feedback mechanisms may depend on the importance of the service being provided. Typically, video or audio streaming services are not mission-critical and can tolerate a certain level of error. For such services, feedback mechanisms can be disabled. On the other hand, some services are mission-critical and require accurate data transmission over the MBSFN network, such as emergency broadcasts or Vehicle-to-Everything (V2X) applications. Feedback mechanisms can be selectively enabled for mission-critical services or applications.

[0057] Figure 7An embodiment of a telecommunications system 700 providing MBMS services is shown, including a core network 710 interconnected to one or more gNB-CUs 720a-720b using a control plane interface N2 and a user plane interface N3. gNB-CU 720a interconnects to a gNB-DU 730a via an F1 interface and to another gNB-CU 720b via an Xn (i.e., X2) logical interface. Cells 740a-740e represent areas covered by gNB-DUs or gNB-CUs. The base stations described in the embodiment are generally referred to as eNBs in the LTE standard. However, in the NR standard, base station becomes a general term encompassing the functions of both gNB-CUs and gNB-DUs. The network nodes described in this embodiment can be a broader term, including both base stations and the core network (generally referred to as the "network"). Because most steps in the embodiment can be performed collaboratively by multiple units across multiple layers, and multiple units can be designed to cover the same functions, this embodiment is not limited to any actual node handling these steps. In one embodiment, MBSFN transmission is performed to provide MBMS services from core network 710 to cells 740a-704e. UEs (not shown) located in cells 740a-740e are part of telecommunications system 700 and can therefore implement the adaptive feedback method together with network nodes, specifically gNB-DUs 730a-730b, gNB-CUs 720a-720b, and core network 710. It is understood that the disclosed adaptive feedback method is merely a software implementation without any hardware changes. Further description is unnecessary because the infrastructure and hardware layout of telecommunications system 700 follow known standards.

[0058] Figure 8 A schematic diagram of a UE 800 according to an embodiment of this application is shown. The UE 800 typically includes a transceiver 802, a display 804, a memory 806, a processor 808, and a Subscriber Identity Module (SIM) card 810. The transceiver 802, also referred to as a combination of transmitter and receiver, functions for both signal transmission and reception, as the hardware architecture of the transmitter and receiver can be shared and integrated into a single module. Embodiments of the adaptive feedback mechanism are essentially software-implemented, manifested as software or firmware stored in the memory 806, executed by the processor 808. Therefore, the hardware architecture of the UE 800 is not specifically limited and can be a telephone, tablet, computer, video streaming device, set-top box, or any subscription-enabled communication device. In summary, embodiments of the UE 800 receive MBMS services while adaptively sending feedback messages. The transceiver 802 acts as a receiver to receive HARQ parameters and as a transmitter to send feedback messages to network nodes based on the HARQ parameters.

[0059] The characteristics of the adaptive feedback method, telecommunications system, base station, and UE summarized in the foregoing description are fully disclosed in the embodiments in conjunction with Figures 1 to 8.

[0060] While the invention has been described by way of example and preferred embodiments, it should be understood that the invention is not limited thereto. Rather, it is intended to cover various modifications and similar arrangements (as will be apparent to those skilled in the art). Therefore, the scope of the appended claims should be interpreted in the broadest possible sense to cover all such modifications and similar arrangements.

Claims

1. An adaptive feedback method for a network node to provide multimedia broadcast multicast service (MBMS) to one or more user equipments (UEs), comprising: Perform Multicast Broadcast Single Frequency Network (MBSFN) transmissions to provide one or more MBMS services, including transmitting multiple Transport Blocks (TBs) and multiple Hybrid Automatic Repeat Request (HARQ) parameters; as well as The first UE sends a feedback message based on HARQ parameters; The HARQ parameters include one or more of the following parameters: Modulation and coding scheme (MCS); New Data Indicator (NDI); Redundant Version (RV); Process ID (PID); Feedback time domain indicator, used to allocate feedback resources in the time domain; as well as Feedback frequency domain indicator, used to allocate feedback resources in the frequency domain; The feedback time domain indicator includes a preset value or a fixed value; as well as The transmission of feedback messages includes: The first UE determines the time interval based on the feedback time domain indicator; and The first UE sends a feedback message during the time interval after receiving the last TB of the MBMS service; wherein the transmission of the HARQ parameters is performed through a combination of one or more of the following methods: One of the HARQ parameters is embedded in the multicast control channel (MCCH) transmitted through the Radio Resource Control (RRC) plane; One of the HARQ parameters is embedded in the multicast channel (MCH) scheduling information (MSI) transmitted via the Media Access Control (MAC) control element (CE); and Embed one of the HARQ parameters in the downlink control information (DCI) in the control area of ​​the MBSFN subframe; The method further includes determining a method for transmitting the first HARQ parameter based on the frequency of change of the first HARQ parameter; The method of determining a way to transmit the first HARQ parameter based on the frequency of change of the first HARQ parameter includes: If the frequency of change of the first HARQ parameter exceeds the first threshold, the first HARQ parameter is embedded in the DCI to transmit the first HARQ parameter. If the frequency of change of the first HARQ parameter is lower than the second threshold, the first HARQ parameter is embedded in the MCCH to transmit the first HARQ parameter; If the frequency of change of the first HARQ parameter is lower than the third threshold, the parameter is embedded into the MSI to transmit the first HARQ parameter.

2. The adaptive feedback method according to claim 1, wherein: The feedback message sent includes: When the first UE fails to decode one or more TBs, it sends a negative acknowledgment (NACK) message to the network node.

3. The adaptive feedback method according to claim 2, further comprising: Network nodes allocate feedback resources shared by multiple UEs for NACK message transmission.

4. The adaptive feedback method according to claim 2, wherein sending the feedback message further comprises: When the first UE successfully decodes all TBs within a predetermined period, it transmits an acknowledgment (ACK) message to the network node.

5. The adaptive feedback method according to claim 4, further comprising: Each UE is allocated separate ACK and NACK feedback resources to send ACK and NACK messages respectively.

6. The adaptive feedback method according to claim 5, further comprising: Allocate ACK feedback resources shared by multiple UEs to send ACK messages; as well as Allocate NACK feedback resources shared by multiple UEs to send NACK messages.

7. The adaptive feedback method according to claim 3, further comprising: Enable or disable retransmission based on retransmission standards; as well as Retransmission includes: after a network node receives a NACK message from the first UE, it retransmits one or more transport blocks.

8. The adaptive feedback method according to claim 7, wherein the retransmission standard includes the service priority corresponding to the MBMS service; and Retransmission is only enabled when the service priority exceeds the first threshold.

9. The adaptive feedback method according to claim 7, further comprising: Obtain one or more Quality of Service (QoS) Flow Identifiers (QFIs), each QFI corresponding to one MBMS service; as well as Service priorities are determined based on QFIs.

10. The adaptive feedback method according to claim 1, wherein: MBSFN transmission includes providing one or more MBMS services within a predetermined period; as well as Sending feedback messages includes transmitting an ACK message only when all TBs within the predetermined period have been successfully decoded.

11. The adaptive feedback method according to claim 10, wherein: Sending feedback messages further includes transmitting a NACK message when at least one TB of decoding fails within a predetermined period.

12. The adaptive feedback method according to claim 1, wherein: The predetermined period is selected from one of the following values: MCH service period (MSP), common subframe allocation period, MCCH repetition period, MCCH modification period, or custom period.

13. The adaptive feedback method according to claim 1, further comprising: A feedback enable signal is generated based on the first condition to enable or disable feedback transmission; The feedback enable signal is transmitted in the first format; as well as If the feedback enable signal enables feedback transmission, the first UE sends a feedback message; wherein the first format is selected from one of the following types: System Information Block 2 (SIB2) message, SIB13 message, signal via MCCH, signal via MAC CE, or signal via DCI.

14. A telecommunications system comprising a network node and one or more user equipments (UEs), wherein the network node performs multicast broadcast single-frequency network (MBSFN) transmission to provide one or more MBMS services, the MBSFN transmission including the transmission of multiple transport blocks (TBs) and multiple hybrid automatic repeat request (HARQ) parameters; as well as The first UE sends a feedback message based on HARQ parameters; The HARQ parameters include one or more of the following parameters: Modulation and coding scheme (MCS); New Data Indicator (NDI); Redundant Version (RV); Process ID (PID); Feedback time domain indicator, used to allocate feedback resources in the time domain; as well as Feedback frequency domain indicator, used to allocate feedback resources in the frequency domain; in: The feedback time domain indicator includes a preset value or a fixed value; and The transmission of feedback messages includes: The first UE determines the time interval based on the feedback time domain indicator; and The first UE sends a feedback message during the time interval after receiving the last TB of the MBMS service; wherein the network node selects one of the following methods to transmit one of the HARQ parameters: Network nodes embed HARQ parameters into the multicast control channel (MCCH) transmitted over the Radio Resource Control (RRC) plane; Network nodes embed HARQ parameters into the multicast channel (MCH) scheduling information (MSI) transmitted via the Media Access Control (MAC) control element (CE); and Network nodes embed HARQ parameters into downlink control information (DCI) located in the control area of ​​MBSFN subframes; The network node selects a method to transmit the first HARQ parameter based on the frequency of change of the first HARQ parameter. The network node selects a method to transmit the first HARQ parameter based on the frequency of change of the first HARQ parameter, including: If the frequency of change of the first HARQ parameter exceeds the first threshold, the network node embeds the first HARQ parameter in the DCI to transmit the first HARQ parameter. If the frequency of change of the first HARQ parameter is lower than the second threshold, the network node embeds the first HARQ parameter in the MCCH to transmit the first HARQ parameter. If the frequency of change of the first HARQ parameter is lower than the third threshold, the network node will embed the parameter into the MSI to transmit the first HARQ parameter.

15. The telecommunications system of claim 14, wherein when the first UE fails to decode one or more TBs, the first UE sends a negative acknowledgment (NACK) message to the network node.

16. The telecommunications system according to claim 15, wherein: Network nodes allocate feedback resources shared by multiple UEs for NACK message transmission.

17. The telecommunications system of claim 15, wherein when the first UE successfully decodes all TBs within a predetermined period, the first UE transmits an acknowledgment (ACK) message to the network node.

18. The telecommunications system according to claim 17, wherein: The network node allocates ACK feedback resources and NACK feedback resources separately for each UE to send ACK messages and NACK messages respectively.

19. The telecommunications system according to claim 17, wherein: Network nodes allocate shared ACK feedback resources among multiple UEs to send ACK messages; and Network nodes allocate NACK feedback resources shared by multiple UEs to send NACK messages.

20. The telecommunications system according to claim 15, wherein: Network nodes enable or disable retransmission based on retransmission standards; as well as If the retransmission function is enabled, the network node will retransmit one or more transport blocks when it receives a NACK message from the first UE.

21. The telecommunications system of claim 20, wherein the retransmission standard includes the service priority corresponding to the MBMS service; and The retransmission function is only enabled when the service priority exceeds the first threshold.

22. The telecommunications system of claim 20, wherein the network node acquires one or more Quality of Service (QoS) Flow Identifiers (QFIs), each QoS Flow Identifier corresponding to an MBMS service, and determines service priority based on the QFIs.

23. The telecommunications system according to claim 14, wherein: Network nodes perform MBSFN transmissions to provide one or more MBMS services within a predetermined period; as well as The first UE transmits an ACK message only when all TBs within the predetermined period have been successfully decoded.

24. The telecommunications system of claim 23, wherein when the first UE fails to decode at least one TB within a predetermined period, the first UE transmits a NACK message.

25. The telecommunications system according to claim 24, wherein: The predetermined period is selected from one of the following values: MCH service period (MSP), common subframe allocation period, MCCH repetition period, MCCH modification period, or custom period.

26. The telecommunications system according to claim 14, wherein: Network nodes generate a feedback enable signal based on a first condition to enable or disable the feedback function; Network nodes transmit feedback enable signals in the first format; as well as If the feedback enable signal enables the feedback function, the first UE sends a feedback message; The first format is selected from one of the following types: System Information Block 2 (SIB2) message, SIB13 message, signal via MCCH, signal via MAC CE, or signal via DCI.

27. A base station that performs Multicast Broadcast Single Frequency Network (MBSFN) transmission to provide one or more MBMS services to one or more User Equipments (UEs), wherein: The base station transmits multiple transport blocks (TBs) and multiple Hybrid Automatic Repeat Request (HARQ) parameters; and The base station receives feedback messages sent from the first UE based on HARQ parameters; The HARQ parameters include one or more of the following parameters: Modulation and coding scheme (MCS); New Data Indicator (NDI); Redundant Version (RV); Process ID (PID); Feedback time domain indicator, used to allocate feedback resources in the time domain; as well as Feedback frequency domain indicator, used to allocate feedback resources in the frequency domain; in: The feedback time domain indicator includes a preset value or a fixed value; and The base station receives the first UE's time interval determined by the feedback time domain indicator; and The base station receives a feedback message sent by the first UE during the time interval after receiving the last TB of MBMS service; The base station selects one of the following methods to transmit the first HARQ parameter: The base station embeds the first HARQ parameter into the multicast control channel (MCCH) transmitted through the radio resource control (RRC) plane; The base station embeds the first HARQ parameter into the multicast channel (MCH) scheduling information (MSI) transmitted via the Media Access Control (MAC) control element (CE); and The base station embeds the first HARQ parameter into the downlink control information (DCI) in the control area of ​​the MBSFN subframe; The base station selects a method to transmit the first HARQ parameter based on the frequency of change of the first HARQ parameter. The base station selects a method to transmit the first HARQ parameter based on the frequency of change of the first HARQ parameter, including: If the frequency of change of the first HARQ parameter exceeds the first threshold, the base station embeds the first HARQ parameter in the DCI to transmit the first HARQ parameter. If the frequency of change of the first HARQ parameter is lower than the second threshold, the base station embeds the first HARQ parameter in the MCCH to transmit the first HARQ parameter. If the frequency of change of the first HARQ parameter is lower than the third threshold, the base station will embed the parameter into the MSI to transmit the first HARQ parameter.

28. The base station of claim 27, wherein when the first UE fails to decode one or more TBs, the base station receives a negative acknowledgment (NACK) message from the first UE.

29. The base station of claim 28, wherein the base station allocates feedback resources shared by a plurality of UEs to send NACK messages.

30. The base station of claim 28, wherein when the first UE successfully decodes all TBs within a predetermined period, the base station receives an acknowledgment (ACK) message sent from the first UE.

31. The base station according to claim 30, wherein the base station allocates ACK feedback resources and NACK feedback resources separately for each UE to send ACK messages and NACK messages respectively.

32. The base station according to claim 30, wherein: The base station allocates shared ACK feedback resources for multiple UEs to send ACK messages; and The base station allocates NACK feedback resources shared by multiple UEs to send NACK messages.

33. The base station according to claim 28, wherein: Base stations enable or disable retransmission based on retransmission standards; as well as If the retransmission function is enabled, the base station will retransmit one or more transport blocks when it receives a NACK message from the first UE.

34. The base station according to claim 33, wherein the retransmission standard includes the service priority corresponding to the MBMS service; and The retransmission function is only enabled when the service priority exceeds the first threshold.

35. The base station according to claim 34, wherein the base station acquires one or more Quality of Service (QoS) Flow Identifiers (QFIs), each QoS Flow Identifier corresponding to an MBMS service, and determines a service priority based on the QFIs.

36. The base station according to claim 27, wherein: The base station performs MBSFN transmissions to provide one or more MBMS services within a predetermined period; as well as When all TBs within the predetermined period are successfully decoded by the first UE, the base station receives an ACK message from the first UE.

37. The base station of claim 36, wherein when the first UE fails to decode at least one TB within a predetermined period, the base station receives a NACK message from the first UE.

38. The base station according to claim 37, wherein: The predetermined period is selected from one of the following values: MCH service period (MSP), common subframe allocation period, MCCH repetition period, MCCH modification period, or custom period.

39. The base station according to claim 27, wherein: The base station generates a feedback enable signal based on a first condition to enable or disable the feedback function; The base station transmits a feedback enable signal in a first format, such that if the feedback enable signal enables the feedback function, the first UE sends a feedback message; and The first format is selected from one of the following types: System Information Block 2 (SIB2) message, SIB13 message, signal via MCCH, signal via MAC CE, or signal via DCI.

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