CN116134920A

CN116134920A - Adaptive feedback method, telecommunication system, base station and user equipment

Info

Publication number: CN116134920A
Application number: CN202080104433.5A
Authority: CN
Inventors: 张鑫; 生嘉
Original assignee: JRD Communication Shenzhen Ltd
Current assignee: JRD Communication Shenzhen Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2023-05-16
Also published as: WO2022021234A1

Abstract

An adaptive feedback method, a telecommunication system, a base station and a UE for a telecommunication system comprising a network node for providing a Multimedia Broadcast Multicast Service (MBMS) to one or more User Equipments (UEs). 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. The first UE transmits a feedback message based on the HARQ parameters.

Description

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

Technical Field

The present invention relates to wireless communications, and more particularly to multimedia broadcast/multicast service (multimedia broadcast/multicast service, MBMS) systems.

Background

MBMS is a point-to-multipoint interface designed to provide 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 (Single Cell Point to Multipoint, SC-PTM) transmissions and broadcast services within a set of multiple cells using multimedia broadcast multicast service single frequency network (Multimedia Broadcast multicast service Single Frequency Network, MBSFN) transmissions. SC-PTM is transmitted using the same LTE downlink shared channel (downlink shared channel) and subframe structure; meanwhile, MBSFN defines a new channel and has a different subframe structure from the regular subframe LTE (regular subframe LTE) to ensure transmission over a set of cells. A potential solution is needed in view of the fact that there is no efficient feedback mechanism in MBMS systems to ensure quality of service (quality of service, QOS). A summary of the proposed embodiments is given below.

Disclosure of Invention

An adaptive feedback method is provided, which may be implemented in a telecommunication system comprising at least a network node and a plurality of User Equipments (UEs), for providing a Multimedia Broadcast Multicast Service (MBMS). The network node, commonly referred to as a base station, may be any upper layer network element in an enodebs, gnbs, or 5G NR system.

The MBMS service is provided by Multicast Broadcast Single Frequency Network (MBSFN) transmission that repeatedly occurs within one period. In MBSFN transmission, a plurality of Transport Blocks (TBs) and a plurality of hybrid automatic repeat request (harq s) parameters are transmitted from a network node. The first UE under MBMS service coverage may conditionally send a feedback message based on the HARQ parameter after receiving the HARQ parameter.

Embodiments of the HARQ parameters include one or more of the following parameters: a Modulation Coding Scheme (MCS), a New Data Indicator (NDI), a Redundancy Version (RV), a Process Identification (PID), a feedback time domain indicator for allocating feedback resources in the time domain, and a feedback frequency domain indicator for allocating feedback resources in the frequency domain. Some HARQ parameters are generally known in existing unicast systems.

Feedback resources generally refer to the various protocol-defined channels, configurations and parameters required by the telecommunications system to complete a transmission. The feedback resources in the time domain may define the timing of sending the feedback message. The feedback resources in the frequency domain may include channel information or bandwidth part information that may be used for feedback message transmission. For example, the feedback time domain indicator may comprise a preconfigured value or a fixed value. When a feedback message is to be transmitted, the first UE determines a time slot according to the feedback time domain indicator and then transmits the feedback message in a time slot after receiving the last TB of the MBMS service.

A number of possible method embodiments are provided. The transmission of the HARQ parameters may be in the same way or in different ways. One of the HARQ parameters may be embedded in a Multicast Control Channel (MCCH) and transmitted through a Radio Resource Control (RRC) plane. Another of the HARQ parameters may be embedded in Multicast Channel (MCH) scheduling information (MSI) and transmitted through a Medium Access Control (MAC) Control Element (CE). Yet another one of the HARQ parameters may be embedded in Downlink Control Information (DCI) located in a control region of the MBSFN subframe and then transmitted to the UE.

An alternative method of transmitting the HARQ parameters is conditionally selectable. For example, how the first HARQ parameter is transmitted may depend on the frequency at which the first HARQ parameter is varied. In one case, if the frequency of change of the first HARQ parameter exceeds a first threshold, the first HARQ parameter is carried and transmitted using DCI. In another case, if the frequency of change of the first HARQ parameter is lower than the second threshold, the first HARQ parameter is carried using the MCCH. Alternatively, if the frequency of change of the first HARQ parameter is below a third threshold, the first HARQ parameter is carried and transmitted using the MSI. The actual values of the first, second and third thresholds may depend on experimentation or experience and are therefore not specifically described herein.

In an embodiment of feedback message transmission, no Acknowledgement (ACK) message is transmitted but only a Negative Acknowledgement (NACK) message. A NACK message is sent when the first UE fails to decode one or more TBs. Conversely, when the first UE successfully decodes all TBs, no ACK message is sent. Thus, only one feedback resource is needed to send the NACK message. The feedback resources may 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 owners of NACK messages, one feedback resource can be reused by multiple UEs. For example, all UEs or subsets of UEs may share one feedback resource or a feedback resource pool for NACK message transmission.

In another case, an ACK message is also sent. The ACK message is sent to the network node only if the first UE successfully decodes all TBs within a predetermined period. In one case, ACK feedback resources and NACK feedback resources are allocated separately for each UE to transmit ACK messages and NACK messages, respectively. In another case, the ACK/NACK feedback resources are shared. ACK feedback resources are allocated and shared by multiple UEs to transmit ACK messages, and NACK feedback resources are allocated and shared by multiple UEs to transmit NACK messages.

An embodiment of a retransmission mechanism is presented. The retransmission function may be conditionally enabled or disabled based on retransmission criteria. If enabled, the network node responds to the NACK message from the first UE by retransmitting one or more TBs corresponding to the NACK message. The retransmission criterion may comprise a service priority corresponding to the MBMS service and retransmission is enabled only if the service priority exceeds a first threshold. As an example of how to determine the service priority, one or more quality of service (QOS) flow identities (QFI) corresponding to the MBMS service may be acquired at the network node side, which QFI may be used as a reference to determine the priority of the service. The first threshold may be experimental or empirical and therefore the actual values are not specified or limited herein.

Various embodiments of MBMS service periodicity are provided. In MBSFN transmission, one or more MBMS services may be provided at a predetermined period. The ACK message may be sent only if all TBs are successfully decoded within a predetermined period. Further, a NACK message may be transmitted when at least one TB of a predetermined period fails to be decoded. An example of the predetermined period may be one of the following values: MCH Service Period (MSP), common subframe allocation period, MCCH repetition period, MCCH modification period or custom period. The enqueue period value is basically calculated in frames. Each TB is scheduled by a Transmission Time Interval (TTI).

In another embodiment, the feedback mechanism may be conditionally enabled or disabled. A feedback enable signal may be generated based on the first condition and transmitted to the first UE. The first UE may send the feedback message only when the feedback enable signal enables the feedback mechanism.

As with the HARQ parameters, the feedback enable signal may be transmitted in various formats. For example, the feedback enable signal may be carried by a system information block 2 (SIB 2) message, a SIB13 message, a signal via MCCH, a signal via MAC CE, or a signal via DCI. The feedback enable signal is also preferably implemented as part of the HARQ parameters transmitted in the above method.

The first condition for determining whether to enable the feedback mechanism may depend on the importance of the service to be provided. Video or audio streaming services are generally not critical tasks and can tolerate a certain degree of error. For such services, the feedback mechanism may be disabled. On the other hand, some services are critical tasks requiring accurate data transmission over MBSFN networks, such as emergency broadcast or internet of vehicles (V2X) applications. The feedback mechanism may be selectively enabled for mission critical services or applications.

Implementation of the adaptive feedback method involves at least the network node and the UE. Accordingly, an embodiment of a telecommunications system implementing an adaptive feedback method is also provided, comprising at least one network node and one or more UEs. In addition, embodiments of a base station and a UE implementing the adaptive feedback method are also provided. Since the features of telecommunications, base stations, network nodes and UEs have been described in the preceding paragraphs, detailed embodiments are not repeated here.

The embodiments are described in more detail below with reference to the accompanying drawings.

Drawings

The invention may be more completely understood in consideration of the following detailed description and examples of embodiments in connection with the accompanying drawings, in which:

FIG. 1a shows a flow chart according to one embodiment of an adaptive feedback method;

fig. 1b shows an embodiment of a Downlink (DL) hybrid automatic repeat request (HARQ) process based on fig. 1 a;

FIG. 2 shows a flow chart of method selection according to one embodiment of an adaptive feedback method;

FIG. 3 shows an embodiment of feedback mode determination;

fig. 4 shows a retransmission-enabling flow chart according to an embodiment of the invention;

figure 5 shows an embodiment of MSBFN transmission;

FIG. 6 shows a flow chart of a feedback enablement mechanism according to an embodiment of the invention;

fig. 7 shows an embodiment of a telecommunication system 700 providing MBMS services; and

fig. 8 shows an embodiment of a User Equipment (UE) 800 according to the present application.

Detailed Description

The following description is of the best contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined with reference to the appended claims.

MBMS is not discussed in NR, and in this specification we refer to the scheduling and transmission mechanism of MBMS in LTE, in combination with new features (new features) in NR. In broadcast/multicast services (MBMS), reliability is one of the requirements that need to be developed. Typically, the reliability level (level of reliability) varies from user application to user application. In the present disclosure, an uplink feedback mechanism (uplink feedback mechanism) is proposed as a solution to improve MBMS reliability.

FIG. 1a shows a flow chart according to one embodiment of an adaptive feedback method. The adaptive feedback method may be implemented in a telecommunication system comprising at least a network node and a plurality of User Equipments (UEs) for providing a Multimedia Broadcast Multicast Service (MBMS). The network node, commonly referred to as a base station, may be any upper layer network element (upper level network unit) in an enodebs, gnbs, or 5G NR system. The most generalized steps of the adaptive feedback method can be summarized in three steps. In step 101, MBSFN transmissions are initialized. MBSFN transmission is called transmission of multiple Transport Blocks (TBs) from a network node to periodically provide one or more MBMS services. In step 103, a plurality of hybrid automatic repeat request (hybrid automatic repeat request, HARQ) parameters are sent from the network node. The HARQ parameter transmission may use various radio resources as will be described below. HARQ parameter transmissions may be periodic, depending on various QOS parameters of the corresponding MBMS service, or triggered by UEs as needed. Embodiments of HARQ parameter transmission may vary in any feasible manner as long as the HARQ parameters are efficiently communicated. In step 105, the UE conditionally sends a feedback message based on the HARQ parameters. Various embodiments regarding feedback transmission are described below.

Fig. 1b shows an embodiment of a Downlink (DL) hybrid automatic repeat request (HARQ) process based on fig. 1 a. The HARQ process is used for transmitting consecutive data blocks by the transmitting end 110 to the receiving end 120. In general, in the HARQ process, the transmitting end 110 is a network node, such as a Base Station (BS), an eNodeB (eNB), or a gNB. The receiver 120 is referred to as a User Equipment (UE), also referred to as a mobile device, under MBSFN network coverage.

In step 102, the sender 110 initializes a new DL assignment. The Transport Block (TB) DATA1 is transmitted. Control information (Control information), such as process ID (process ID), new data indicator (New Data Indicator, NDI), redundancy version (Redundancy Version, RV), and feedback resource (feedback resource) (timing and frequency) is incorporated into Downlink Control Information (DCI) messages. In step 104, if the receiving end 120 successfully decodes the received TB data1, an ACK message is transmitted to the transmitting end 110. In this case, in step 106, the transmitting end 110 continues to transmit the next TB data2 and the same process ID and corresponding control information to the receiving end 120. If the receiving end fails to receive and/or decode the TB DATA2, the receiving end 120 transmits a NACK message to the transmitting end 110 in step 108. In step 112, retransmission is triggered, wherein the sender 110 retransmits the same TB data2 and 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 sender 110. MBMS services are regularly provided by Multicast Broadcast Single Frequency Network (MBSFN) transmission or the like. The receiving end 120 under MBMS service coverage may conditionally send feedback messages based on the control information,

e.g. steps

104, 108 and 114, after receiving the control information sent in step 110.

The above control information, hereinafter referred to as HARQ parameters, generally indicates states, values, modes, resources and configurations defined by various protocols during transmission. Embodiments may include, but are not limited to, the following parameters: a modulation coding scheme (modulation coding scheme, MCS), a New Data Indicator (NDI), a Redundancy Version (RV), a Process Identification (PID), a feedback time domain indicator (feedback time domain indicator) for allocating feedback resources in the time domain, and a feedback frequency domain indicator (feedback frequency domain indicator) for allocating feedback resources in the frequency domain. Some HARQ parameters are generally known in existing unicast systems. Feedback resources generally refer to the various protocol-defined channels, configurations and parameters required by the telecommunication system to complete a transmission. The feedback resources in the time domain may include slot information (time slot information), such as a time gap (time gap) defining the timing of the transmission of the feedback message. The feedback resources in the frequency domain may include channel information (channel information) or bandwidth part information (bandwidth part information) available for feedback message transmission. For example, the feedback time domain indicator may comprise a preconfigured value or a fixed value. When a feedback message is to be transmitted, the first UE determines a time slot according to the feedback time domain indication and then transmits the feedback message in a time slot after receiving the last TB of the MBMS service.

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

/>

For example, in the SIB13 IE, the subframe allocated for the MCCH message is carried by the IE MBSFN-arealnfolist-r 9. The MCCH modification period is carried by the IE MBMS-NotificationConfig.

Second, the UE may also decode the MCCH carried message to obtain various parameters such as common subframe allocation (Common Subframe Allocation, CSA), MCH subframe allocation (MCH Subframe Allocation, MSA) and MCH scheduling period (MCH Scheduling Period, MSP). An example of an mbsfnarea configuration message is shown below, carried by the MCCH.

The CSA is carried by the IE common sf-Alloc-r9 and indicates a common pattern (common pattern) of subframes occupied by all MCHs within the same MBSFN area, which is periodically repeated with a CSA period defined by the IE common sf-AllocPeriod-r 9. MSA is carried by IEpmch-InfoList-r 9. The actual MSA of each Multicast Channel (MCH) is defined by the CSA period carried by the CSA and MCCH. The tail of the MSA (tail port) represents the last subframe of the MCH in the CSA period. The MSP is carried by IEpmch-InfoList-r 9 and is configurable according to the MCH.

A third way for the UE to receive MBMS control information is via MCH scheduling information (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 (Multicasting Traffic Channels, MTCHs) and optionally transmits the MCCH on the MCH. MSI is provided in accordance with the MCH to indicate which subframes each MTCH uses during the MSP and to indicate whether the transmission of the MTCH has been scheduled or suspended by the eNB.

As described, each HARQ parameter may be selectively carried by the same or different methods, thereby presenting possible implementations that vary exponentially.

The method of transmitting the HARQ parameters is conditionally selectable. Fig. 2 shows a flow chart of method selection according to one embodiment of an adaptive feedback method. In step 201, conditions for HARQ parameters are determined. Different conditions may lead to different processes. For case 1, the step goes to step 205, for case 2, to step 207, for case 3, to step 209. For example, how the HARQ parameters are transmitted may depend on the frequency at which the HARQ parameters are varied. In step 203, if the frequency of change of the HARQ parameter exceeds a first threshold, DCI bearer and transmission HARQ parameters are used in step 205.

Similarly, when step 203 matches case 2, for example, the frequency of change of the HARQ parameter is less than the second threshold, step 207 is continued. The MCCH is used to transmit HARQ parameters in step 207.

Likewise, when step 203 matches case 3, e.g., the frequency of change of the first HARQ parameter is below a third threshold, the process proceeds to step 209. The MSI is thus used in step 209 for carrying and transmitting the first HARQ parameters. The actual values of the first, second and third thresholds may be experimentally or empirically related. The conditional checking of HARQ parameters may be based on many other factors and is not limited to a change in frequency or value.

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

In some other types of MBMS services, an ACK message may also be required. The ACK message is sent only if the first UE successfully decodes all TBs for a predetermined period (predetermined period). In one case, each UE is allocated a separate ACK feedback resource and a separate NACK feedback resource to transmit an ACK message and a NACK message, respectively. In another case, the ACK/NACK resources may be shared if the network node does not need to distinguish the source of the ACK/NACK message. For example, ACK feedback resources are allocated and shared by all UEs or subsets of UEs for ACK message transmission, and likewise NACK feedback resources are allocated and shared by all UEs or subsets of UEs for NACK message transmission.

A mechanism to determine whether to transmit an ACK message may be required. Fig. 3 shows an embodiment of feedback mode determination. In step 301, a conditional checking mechanism is provided that determines whether to send an ACK message. Case 1 goes to step 303 where various conditions may be determined as a basis for enabling (enable) or disabling (disable) ACK transmission. For example, the condition may be related to QOS requirements or predetermined according to the service type of an upper layer. Step 305 is processed in case 2, where only a NACK is required for a certain service or condition. Conversely, process step 307 is to send ACK and NACK messages.

On the network node side, it is also considered whether or not retransmission (retransmission) is performed. Fig. 4 shows a retransmission-enabling flow chart according to an embodiment of the invention. In step 401, a retransmission function may be conditionally enabled or disabled based on a retransmission criterion (retransmission criterion). In step 403, the retransmission criterion is checked. The retransmission criterion may include a service priority (service priority) corresponding to the MBMS service, and retransmission is enabled only when the service priority exceeds a first threshold. As an example of how to determine the service priority, one or more quality of service (QOS) flow identifiers (QFI) corresponding to the MBMS service may be acquired at the network node side, and these qfs may be used as references to determine the service priority. The first threshold may be experimentally or empirically related and thus the actual values are not specified or limited herein. In case 1 the process goes to step 405 where retransmission is enabled. In that case, the network node retransmits one or more TBs if necessary, for example, upon receipt of a NACK message. Conversely, the process goes to step 407, where no retransmission is performed in any case.

Fig. 5 shows an embodiment of MBSFN scheduling. A plurality of downlink frames are transmitted consecutively, each 16 frames being referred to as a Common Subframe Allocation (CSA) period 540. Each frame 502 includes 10 subframes 504, equivalent in time to 20 slots, as known in the 5G standard. A subset of downlink subframes 504 in radio frame 402 may be configured by higher layers (highers) as MBSFN subframes for carrying MBMS service TBs. Each MBMS service may include a plurality of TBs transmitted within a MCH Service Period (MSP). Various embodiments of MBMS service periods are provided. In MBSFN transmission, one or more MBMS services may be provided within a predetermined period. In fig. 4, three services are illustrated as examples.

Services

1 and 3 may have 16 frames of MSP, such as MSP1 560. Service 2 may have a 32 frame MSP, such as MSP2 570. In each CSA cycle 540, TBs are transmitted in MCH1 510 of service 1, MCH2 520 of service 2, and MCH3 530 of service 3.

In a predetermined period, an ACK message may be sent only when all TBs are successfully decoded. Further, a NACK message may be transmitted when at least one TB of a predetermined period fails to be decoded. An example of the predetermined period may be one of the following values: MSP 560/570, CSA period 540, MCCH repetition period (repetition period) 540, MCCH modification period (modification period) 550 or custom period (MSP). The enqueue period (period) value is basically calculated in frames.

In one embodiment, the condition for transmitting the ACK/NACK message is determined using the MSP as a predetermined period. After decoding all TBs on MCH1 510, MCH2 520, and MCH3 530 during the corresponding MSPs MSP1 and MSP2 570, the UE sends a feedback message based on and (and) logic operations of all decoding results of the TBs. Assuming MSP1 560 is 16 frames for

services

1 and 3 and MSP2 570 is 32 frames for service 2, there are 11 MBSFN Subframes (TBs) in MCH1 510 during MSP1 560, 2 MBSFN subframes in MCH2 520 during MSP2 570, and 4 MBSFN subframes in MCH3 530 during MSP1 560. On MCH1 510, if any of the 11 TBs fails decoding, the UE sends a NACK message. The same procedure is performed for MCH2 520 and MCH3 530. If all TBs within the respective MSPs of the three services are decoded correctly, the UE may conditionally send an ACK message or nothing as described in step 303 of fig. 3.

Other possible embodiments are provided by replacing the CSA period 540 (16 frames), the MCCH repetition period 550 (based on MCCH-repetition period-r9 IE, which may be 32, 64, 128, 256 frames), and the MCCH modification period 580 (based on MCCH-modification period-r9 IE, which may be 512 or 1024 frames) with predetermined periods. The predetermined period may also be a period tailored to the needs of the user.

In further embodiments, the feedback mechanism may be conditionally enabled or disabled. Fig. 6 shows a flow chart of a feedback enablement mechanism according to an embodiment of the invention. In step 602, a process is initialized to determine whether a feedback mechanism is enabled. In step 604, the condition is checked. If the condition is met in case 1, then in process step 606. In step 606, a feedback mechanism is enabled. For example, a feedback enable signal (feedback enablement signal) may be generated based on the condition and sent to the UE indicating that the UE sends a feedback message when the feedback mechanism is enabled. On the other hand, if case 2 is met, the process passes to step 608 where no feedback mechanism is required. In step 608, a feedback enable signal may be generated to carry instructions to disable the feedback mechanism such that the UE stops sending feedback messages when receiving the feedback enable signal. In practice, the actual conditions or circumstances checked in step 604 may depend on the service QOS requirements, user customization (user customizations), or any factor regarding performance and efficiency. The present embodiment is not limited to the implementation of step 604.

As with the HARQ parameters, the feedback enable signal may be transmitted in various formats. For example, the feedback enable signal may be carried by a system information block 2 (System Information Block, sib2) message, SIB13 message, a signal via MCCH, a signal via MAC CE, or a signal via DCI. The feedback enable signal is also preferably implemented as part of the HARQ parameters transmitted in the above method.

The first condition for determining whether to enable the feedback mechanism may depend on the importance of the service to be provided. Video or audio streaming services are generally not critical tasks and can tolerate a certain degree of error. For such services, the feedback mechanism may be disabled. On the other hand, some services are critical tasks requiring accurate data transmission over MBSFN networks, such as emergency-to-evaluation (V2X) applications. The feedback mechanism may be selectively enabled for mission critical services or applications.

Fig. 7 shows an embodiment of a telecommunications system 700 providing MBMS services comprising a core network 710 interconnected to one or more gnbs-CUs a-720 b using a control plane interface N2 and a user plane interface N3. gNB-CU 720a is interconnected to gNB-DU 730a through an F1 interface and to another gNB-CU 720b through an Xn (i.e., X2) logical interface. Cells 740 a-740 e represent areas covered by gNB-DUs or gNB-CUs. The base station described in the embodiments is generally referred to as an eNB in the LTE standard. However, in the NR standard, the base station is a generic term covering both gNB-CU and gNB-DU functions. The network nodes described in this embodiment may be in broader terms including base stations and core networks (commonly referred to as "networks"). Since most of the steps in an embodiment may be performed collectively by a plurality of units across multiple hierarchies, and the plurality of units may be designed to cover the same function, the present embodiment is not limited to any actual node that handles these steps. In one embodiment, MBSFN transmission is performed to provide MBMS services from core network 710 to cells 740 a-704 e. UEs (not shown) located within cells 740 a-740 e are part of telecommunications system 700 and thus may implement an adaptive feedback method with network nodes, in particular, gNB-DUs 730 a-730 b, gNB-CUs a-720 b, and core network 710. It is to be understood that the disclosed adaptive feedback method is only a software implementation, with no hardware changes. No further description is necessary as the infrastructure and hardware arrangement of the telecommunications system 700 complies with known standards.

Fig. 8 shows a schematic diagram of a UE 800 according to an embodiment of the present application. The UE 800 generally includes a transceiver 802, a display 804, a memory 806, a processor 808, and a subscriber identity module (Subscriber Identity Module, SIM) card 810. The transceiver 802, also referred to as a combination of transmitter and receiver, works for both signal transmission and reception, as the hardware structures of the transmitter and receiver may be shared and integrated into one module. An embodiment of the adaptive feedback mechanism is basically a software implementation, represented as software or firmware stored in the memory 806 that is executed by the processor 808. Thus, the hardware structure of the UE 800 is not particularly limited and may be a phone, a tablet, a computer, a video streaming device, a set top box, or any communication device supporting subscribers. In summary, embodiments of UE 800 receive MBMS services while adaptively transmitting feedback messages. The transceiver 802 functions as a receiver to receive HARQ parameters and as a transmitter to send feedback messages to the network node based on the HARQ parameters.

Summarizing the features of the adaptive feedback method, the telecommunication system, the base station and the UE by the foregoing description is fully disclosed in the embodiments in connection with fig. 1 to 8.

While the invention has been described by way of example and preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). The scope of the appended claims is therefore to be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.

Claims

1. An adaptive feedback method for a network node to provide a Multimedia Broadcast Multicast Service (MBMS) to one or more User Equipments (UEs), comprising:

performing Multicast Broadcast Single Frequency Network (MBSFN) transmissions to provide one or more MBMS services, including transmitting a plurality of Transport Blocks (TBs) and a plurality of hybrid automatic repeat request (HARQ) parameters; and

the first UE transmits a feedback message based on the HARQ parameters.

2. The adaptive feedback method of claim 1, wherein the HARQ parameters include one or more of the following parameters:

modulation Coding Scheme (MCS);

new Data Indicator (NDI);

redundancy Version (RV);

process Identification (PID);

a feedback time domain indicator for allocating feedback resources in the time domain; and

a feedback frequency domain indicator for allocating feedback resources in the frequency domain.

3. The adaptive feedback method of claim 2, wherein:

the feedback time domain indicator comprises a preset value or a fixed value; and

the transmission of the feedback message includes:

the first UE determines a time gap according to the feedback time domain indicator; and

the first UE transmits a feedback message in a time gap after receiving the last TB of the MBMS service.

4. The adaptive feedback method of claim 2, wherein the transmission of HARQ parameters is performed by a combination of one or more of the following methods:

embedding one of the HARQ parameters in a Multicast Control Channel (MCCH) transmitted through a Radio Resource Control (RRC) plane;

embedding one of the HARQ parameters in Multicast Channel (MCH) scheduling information (MSI) transmitted through a Medium Access Control (MAC) Control Element (CE); and

one of the HARQ parameters is embedded in Downlink Control Information (DCI) located in a control region of the MBSFN subframe.

5. The adaptive feedback method of claim 4, further comprising determining a method to transmit the first HARQ parameter according to a frequency of change of the first HARQ parameter.

6. The adaptive feedback method of claim 5, further comprising:

if the frequency of the change of the first HARQ parameter exceeds a first threshold, embedding the first HARQ parameter in the DCI to transmit the first HARQ parameter.

7. The adaptive feedback method of claim 5, further comprising:

if the change frequency of the first HARQ parameter is lower than the second threshold value, embedding the first HARQ parameter in the MCCH to transmit the first HARQ parameter.

8. The adaptive feedback method of claim 5, further comprising:

if the frequency of change of the first HARQ parameter is below a third threshold, the parameter is embedded in the MSI to transmit the first HARQ parameter.

9. The adaptive feedback method of claim 1, wherein:

the sending of the feedback message includes:

when the first UE fails to decode one or more TBs, a Negative Acknowledgement (NACK) message is sent to the network node.

10. The adaptive feedback method of claim 9, further comprising:

the network node allocates feedback resources shared by the plurality of UEs for NACK message transmission.

11. The adaptive feedback method of claim 9, wherein transmitting a feedback message further comprises: an Acknowledgement (ACK) message is transmitted to the network node when the first UE successfully decodes all TBs within a predetermined period.

12. The adaptive feedback method of claim 11, further comprising:

ACK feedback resources and NACK feedback resources are allocated separately for each UE to transmit ACK messages and NACK messages, respectively.

13. The adaptive feedback method of claim 11, further comprising:

allocating ACK feedback resources shared by a plurality of UEs to send an ACK message; and

NACK feedback resources shared by a plurality of UEs are allocated to transmit NACK messages.

14. The adaptive feedback method of claim 9, further comprising:

enabling or disabling retransmission based on retransmission criteria; and

the retransmission includes: the network node retransmits the one or more transport blocks after receiving the NACK message from the first UE.

15. The adaptive feedback method of claim 14, wherein the retransmission criteria includes a service priority corresponding to the MBMS service; and

retransmission is enabled only when the service priority exceeds a first threshold.

16. The adaptive feedback method of claim 14, further comprising:

acquiring one or more quality of service (QOS) flow identifiers (qffs), each corresponding to one MBMS service; and

service priority is determined based on QFAs.

17. The adaptive feedback method of claim 1, wherein:

MBSFN transmission includes providing one or more MBMS services for a predetermined period; and

sending the feedback message includes transmitting an ACK message only if all TBs within a predetermined period are successfully decoded.

18. The adaptive feedback method of claim 17, wherein:

the transmitting of the feedback message further includes transmitting a NACK message when at least one TB fails to decode within a predetermined period.

19. The adaptive feedback method of 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.

20. The adaptive feedback method of claim 1, further comprising:

generating a feedback enable signal to enable or disable feedback transmission based on the first condition;

transmitting a feedback enable signal in a first format; and

if the feedback enabling 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 (SIB 2) message, SIB13 message, a signal via MCCH, a signal via MAC CE, or a signal via DCI.

21. 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) transmissions to provide one or more MBMS services, the MBSFN transmissions comprising transmitting a plurality of Transport Blocks (TBs) and a plurality of hybrid automatic repeat request (HARQ) parameters; and

The first UE transmits a feedback message based on the HARQ parameters.

22. The telecommunications system of claim 21, wherein the HARQ parameters include one or more of the following:

modulation Coding Scheme (MCS);

new Data Indicator (NDI);

redundancy Version (RV);

process Identification (PID);

23. The telecommunications system of claim 22, wherein:

the transmission of the feedback message includes:

24. The telecommunications system of claim 22, wherein the network node selects one of the following to transmit one of the HARQ parameters:

the network node embeds HARQ parameters in a Multicast Control Channel (MCCH) transmitted through a Radio Resource Control (RRC) plane;

the network node embeds HARQ parameters in Multicast Channel (MCH) scheduling information (MSI) transmitted through a Medium Access Control (MAC) Control Element (CE); and

The network node embeds HARQ parameters in Downlink Control Information (DCI) located in a control region of the MBSFN subframe.

25. The telecommunications system of claim 24, wherein the network node selects a method to transmit the first HARQ parameter based on a frequency of change of the first HARQ parameter.

26. The telecommunications system of claim 25, wherein the network node embeds the first HARQ parameter in the DCI to transmit the first HARQ parameter if a frequency of variation of the first HARQ parameter exceeds a first threshold.

27. The telecommunication system of claim 25, wherein 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 below a second threshold.

28. The telecommunications system of claim 25, wherein if the frequency of variation of the first HARQ parameter is below a third threshold, the network node embeds the parameter in the MSI to transmit the first HARQ parameter.

29. The telecommunications system of claim 21, wherein the first UE sends a Negative Acknowledgement (NACK) message to the network node when the first UE fails to decode one or more TBs.

30. The telecommunications system of claim 29, wherein:

31. The telecommunications system of claim 29, wherein the first UE transmits an Acknowledgement (ACK) message to the network node when the first UE successfully decodes all TBs within a predetermined period.

32. The telecommunications system of claim 31, wherein:

the network node allocates ACK feedback resources and NACK feedback resources for each UE individually to transmit ACK messages and NACK messages, respectively.

33. The telecommunications system of claim 31, wherein:

the network node allocates ACK feedback resources shared by a plurality of UEs to send an ACK message; and

the network node allocates NACK feedback resources shared by the plurality of UEs to transmit the NACK message.

34. The telecommunications system of claim 29, wherein:

the network node enables or disables retransmission based on retransmission criteria; and

if the retransmission function is enabled, the network node retransmits one or more transport blocks upon receiving a NACK message from the first UE.

35. The telecommunications system of claim 34, wherein the retransmission criteria includes a service priority corresponding to the MBMS service; and

the retransmission function is enabled only when the service priority exceeds a first threshold.

36. The telecommunications system of claim 34, wherein the network node obtains one or more quality of service (QOS) flow identities (qffs), each corresponding to one of the MBMS services, and determines the service priority based on the qffs.

37. The telecommunications system of claim 21, wherein:

the network node performs MBSFN transmission to provide one or more MBMS services for a predetermined period; and

the first UE transmits an ACK message only when all TBs within a predetermined period are successfully decoded.

38. The telecommunications system of claim 37, wherein the first UE transmits the NACK message when the first UE fails at least one TB decode within a predetermined period.

39. The telecommunications system of claim 38, wherein:

40. The telecommunications system of claim 21, wherein:

the network node generating a feedback enable signal to enable or disable the feedback function based on the first condition;

the network node transmitting a feedback enable signal in a first format; and

if the feedback enabling signal enables the feedback function, the first UE sends a feedback message;

wherein the first format is selected from one of the following types: system information block 2 (SIB 2) message, SIB13 message, a signal via MCCH, a signal via MAC CE, or a signal via DCI.

41. 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 transmitting a plurality of Transport Blocks (TBs) and a plurality of hybrid automatic repeat request (HARQ) parameters; and

the base station receives a feedback message transmitted from the first UE based on the HARQ parameters.

42. The base station of claim 41, wherein the HARQ parameters include one or more of the following parameters:

modulation Coding Scheme (MCS);

new Data Indicator (NDI);

redundancy Version (RV);

process Identification (PID);

43. The base station of claim 42, wherein:

the base station receives the feedback time domain indicator and determines a time gap according to the feedback time domain indicator; and

the base station receives a feedback message sent by the first UE in a time interval after receiving the last TB of the MBMS service.

44. The base station of claim 42, wherein the base station selects one of the following to transmit the first HARQ parameters:

the base station embeds the first HARQ parameter in a Multicast Control Channel (MCCH) transmitted through a Radio Resource Control (RRC) plane;

the base station embeds a first HARQ parameter in Multicast Channel (MCH) scheduling information (MSI) transmitted through a Medium Access Control (MAC) Control Element (CE); and

The base station embeds the first HARQ parameter in Downlink Control Information (DCI) located in a control region of the MBSFN subframe.

45. The base station of claim 44, wherein the base station selects a method to transmit the first HARQ parameter based on the frequency of change of the first HARQ parameter.

46. The base station of claim 45, wherein if the frequency of variation of the first HARQ parameter exceeds a first threshold, the base station embeds the first HARQ parameter in the DCI to transmit the first HARQ parameter.

47. The base station of claim 45, wherein if the frequency of the variation of the first HARQ parameter is below the second threshold, the base station embeds the first HARQ parameter in the MCCH to transmit the first HARQ parameter.

48. The base station of claim 45, wherein if the frequency of variation of the first HARQ parameter is below a third threshold, the base station embeds the parameter into the MSI to transmit the first HARQ parameter.

49. The base station of claim 41, wherein the base station receives a Negative Acknowledgement (NACK) message from the first UE when the first UE fails to decode one or more TBs.

50. The base station of claim 49 wherein the base station allocates feedback resources shared by the plurality of UEs to transmit the NACK message.

51. The base station of claim 49, wherein the base station receives an Acknowledgement (ACK) message sent from the first UE when the first UE successfully decodes all TBs within a predetermined period.

52. The base station of claim 51, wherein the base station allocates ACK feedback resources and NACK feedback resources for each UE individually to transmit ACK messages and NACK messages, respectively.

53. The base station of claim 51, wherein:

the base station allocates ACK feedback resources shared by a plurality of UEs to send an ACK message; and

the base station allocates NACK feedback resources shared by a plurality of UEs to transmit a NACK message.

54. The base station of claim 49, wherein:

the base station enables or disables retransmission based on retransmission criteria; and

if the retransmission function is enabled, the base station retransmits one or more transport blocks upon receiving a NACK message from the first UE.

55. The base station of claim 54 wherein the retransmission criteria comprises a service priority corresponding to the MBMS service; and

56. The base station of claim 54 wherein the base station obtains one or more quality of service (QOS) flow identities (QFAs), each corresponding to an MBMS service, and determines the service priority based on the QFAs.

57. The base station of claim 41, wherein:

the base station performing MBSFN transmission to provide one or more MBMS services for a predetermined period; and

The base station receives an ACK message from the first UE when all TBs within a predetermined period are successfully decoded by the first UE.

58. The base station of claim 57 wherein the base station receives a NACK message from the first UE when the first UE fails at least one TB decode within a predetermined period.

59. The base station of claim 58, 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.

60. The base station of claim 41, wherein:

the base station generating a feedback enable signal to enable or disable the feedback function based on the first condition;

the base station transmits a feedback enable signal in a first format such that if the feedback enable signal enables a feedback function, the first UE transmits a feedback message; and

61. A user equipment receiving one or more MBMS services from an MBSFN network comprising a network node connectable to a plurality of UEs, wherein:

MBSFN transmission includes transmitting a plurality of Transport Blocks (TBs) and a plurality of hybrid automatic repeat request (harq s) parameters; and

The UE receives the TBs and sends a feedback message based on the HARQ parameters.

62. The user equipment of claim 61, wherein the HARQ parameters comprise one or more of the following parameters:

modulation Coding Scheme (MCS);

new Data Indicator (NDI);

redundancy Version (RV);

process Identification (PID);

63. The user equipment of claim 62, wherein:

the transmission of the feedback message includes:

the UE determines a time gap according to the feedback time domain indicator; and

the UE transmits a feedback message in a time slot after receiving the last TB of the MBMS service.

64. The user equipment of claim 61 wherein the UE sends a Negative Acknowledgement (NACK) message to the network node when the UE fails to decode one or more TBs.

65. The user equipment of claim 64 wherein the feedback resources are allocated by the network node to all or part of the UEs for sharing, the UEs using the feedback resources for NACK message transmission.

66. The user equipment of claim 64 wherein the UE sends an Acknowledgement (ACK) message to the network node after successfully decoding one or more TBs.

67. The user equipment of claim 66, wherein:

all UEs or subsets of UEs share ACK feedback resources and NACK feedback resources; and

the UE sends an ACK message by using an ACK feedback resource; and

the UE transmits a NACK message using a NACK feedback resource.

68. The user equipment of claim 61, wherein:

the network node provides one or more MBMS services for a predetermined period; and

the UE transmits an ACK message only when all TBs within a predetermined period are successfully decoded.

69. The user equipment of claim 68 wherein the UE sends a NACK message when the UE fails at least one TB decode for a predetermined period.

70. The user equipment of claim 68, 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.

71. The user equipment of claim 61, wherein:

the UE receives a feedback enabling signal sent by a network node; and

and the UE sends a feedback message according to the state of the feedback enabling signal.