TWI762999B - User equipment and buffer status report cancellation method based on carrier aggregation and integrated access and backhaul - Google Patents

Abstract

A user equipment and a buffer status report (BSR) cancellation method are provided. In the method, the data duplication is activated on one or more data units of packet data convergence protocol (PDCP). The data duplication is that, in the carrier aggregation (CA), one data unit corresponds to two or more component carriers provided by a base station based on integrated access and backhaul (IAB) mechanism. For each data unit, two or more BSRs are triggered, and each BSR corresponds to one logical channel. Then, at least one BSR is canceled according to a canceling condition. Accordingly, the IAB network can be applied with multiple BSR cancellation.

Description

User Equipment and Buffer Status Report Cancellation Method Based on Carrier Aggregation and Access and Posthaul

The present invention relates to a radio resource management technology, and more particularly, to a user equipment (User Equipment, UE) and a buffer status report (Buffer Status Report, BSR) cancellation method.

In uplink (UL) resource scheduling, the user equipment can transmit a Sounding Reference Signal (SRS) to let the base station know the quality of the uplink channel. Next, if the user equipment has a demand for data transmission but has not obtained uplink resources, the user equipment may send a scheduling request (SR) to inform the base station that there is a resource demand. After receiving the scheduling request, the base station can allocate a small number of resources for the user equipment to inform the amount of data to be transmitted. Then, the user equipment can transmit a buffer status report about the data amount, so that the base station can allocate uplink resources for the data amount. However, due to the limited uplink resources, the triggered buffer status report may inevitably be cancelled, so that the user equipment needs to request resources again.

In view of this, embodiments of the present invention provide a user equipment and a method for canceling a buffer status report, which provides a buffer status report under Carrier Aggregation (CA) for an Integrated Access and Backhaul (IAB) mechanism. cancellation.

The buffer status report cancellation method according to the embodiment of the present invention is applicable to the user equipment and includes (but not limited to) the following steps: enabling data replication for one or more data units of the Packet Data Convergence Protocol (PDCP) (data duplication), the data duplication is to map data units to two or more Component Carriers (CCs) provided by a base station integrating access and backhaul mechanisms under carrier aggregation. Two or more buffer status reports are triggered for each data unit, and each buffer status report corresponds to a Logical Channel (LCH). The buffer status reporting on at least one of the logical channels is cancelled according to the cancellation condition.

The user equipment of the embodiment of the present invention includes (but is not limited to) a transmitter and a processor. The transmitter uses the transmitted signal. The processor is coupled to the transmitter and is configured to enable data replication for one or more data units of the packet data aggregation protocol, trigger two or more buffer status reports for each data unit, and cancel logic based on cancellation conditions Buffer status report on at least one of the channels. The data replication is to map data units to two or more component carriers provided by a base station integrating access and backhaul mechanisms under carrier aggregation. Each buffer status report corresponds to a logical channel, and those buffer status reports are transmitted through the transmitter.

Based on the above, the user equipment and the method for canceling the buffer status report according to the embodiments of the present invention can use several component carriers provided by the base station with integrated access and backhaul mechanism to transmit the original data unit and the duplicated data unit respectively, and respond If the cancellation conditions are met, the data unit corresponding to the triggered buffer status report is cancelled. Thereby, it can be applied to the integrated access and posthaul mechanism of the fifth generation (5G) mobile communication.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, the following embodiments are given and described in detail with the accompanying drawings as follows.

FIG. 1 is a schematic diagram of a communication system 1 according to an embodiment of the present invention. Please refer to FIG. 1 , the communication system 1 includes (but is not limited to) one or more integrated access and backhaul (Integrated Access and Backhaul, IAB)-node (node) 10, one or more IAB-supply A donor 30 , one or more core network entities 50 , and one or more user equipment 100 .

Both the IAB-node 10 and the IAB-provider 30 are base stations that support the IAB mechanism, and can be next-generation node B (gNB), home evolved node B (Home Evolved Node B, HeNB), base transceiver system (Base Transceiver System, BTS), repeater (relay), repeater (repeater) or other types of base stations.

In 5G New Radio (NR), release-16 released by the 3rd Generation Partnership Project (3GPP) incorporates the IAB mechanism into the standard and can be applied to short-range access for high-density deployments Networks (eg, small cells). The IAB mechanism includes multiple-hop post-transmission. For example, the IAB-node 10 or the IAB-provider 30 may provide an access link AL to the user equipment 100 and transmit directly or indirectly (hop) to other IABs via a backhaul link BL - Node 10 or IAB-Provider 30. The access link AL and the backhaul link BL may use the same or different carrier frequencies (eg, their operating frequencies are between 4 GHz and 30 GHz). In addition, under layer 2 (L2) relaying, Quality of Service (QoS) processing can be limited to the Radio Access Network (RAN) level, thereby reducing inter-core network latency. Signaling costs.

In order to realize the backhaul link (BL), the IAB-node 10 may include a Mobile Termination (MT) function (can be regarded as a component of a mobile device) and a next-generation Node B function or a distributed unit function (can be regarded as a base station) elements) to forward data from user equipment 100, other IAB-nodes 10 or IAB-providers 30.

On the other hand, a next-generation Node B can split functions to form a central unit (Central Unit, CU) and one or more distributed units (Distributed Units, DUs). The central unit may be responsible for functions such as Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP), and the decentralized unit may be responsible for radio link control ( Radio Link Control, RLC), media access control (Media Access Control, MAC) and physical (physical, PHY) layer functions. In some embodiments, the IAB-node 10 may implement a decentralized unit, and the IAB-supplier 30 may implement a central unit, or both a decentralized unit and a central unit.

The core network entity 50 is connected to the IAB-provider 30, and can be regarded as a certain network entity in the core network, and can be a server, a backend host, a desktop computer, or other devices.

The user equipment 100 may have various implementations, such as, but not limited to, a mobile station, an advanced mobile station (AMS), a telephone device, a customer premise equipment (CPE), and a wireless sensor. tester, etc.

FIG. 2 is a block diagram of components of the user equipment 100 according to an embodiment of the present invention. Referring to FIG. 2 , the user equipment 100 includes (but is not limited to) an antenna 110 , a receiver 120 , a transmitter 130 , an analog-to-digital and digital-to-analog converter 140 , a storage 150 and a processor 160 . The antenna 110 is coupled to the receiver 120 and the transmitter 130 . The analog-to-digital and digital-to-analog converters 140 are coupled to the receiver 120 , the transmitter 130 and the processor 160 . The processor 160 is further coupled to the storage 150 .

The receiver 120 and the transmitter 130 are used for wirelessly receiving downlink (downlink) signals and transmitting uplink (uplink) signals through the antenna 110 , respectively. Receiver 120 and transmitter 130 may also perform analog signal processing operations such as low noise amplification, impedance matching, frequency mixing, up or down conversion, filtering, amplification, and the like. The analog-to-digital and digital-to-analog converters 140 are configured to convert from an analog signal format to a digital signal format during downlink signal processing, and to convert from a digital signal format to an analog signal format during uplink signal processing.

The storage 150 can be any type of fixed or removable random access memory (Random Access Memory, RAM), read-only memory (Read-Only Memory, ROM), flash memory (Flash Memory), or similar components or a combination of the above elements. The storage 150 records program codes, device configurations, codebooks, buffered or permanent data, and records software modules and data related to various communication protocols such as RRC layer, PDCP layer, RLC layer, and MAC layer.

The processor 160 is configured to process digital signals and execute programs according to exemplary embodiments of the present invention, and may access or load data and software modules recorded in the storage 150 . The function of the processor 160 can be achieved by using, for example, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processing (DSP) chip, a field programmable logic gate array (Field Programmable Gate Array). Programmable Gate Array, FPGA) and other programmable units to implement. The functions of the processor 160 can also be implemented by an independent electronic device or an integrated circuit (IC), and the operations of the processor 160 can also be implemented by software.

Hereinafter, the method according to the embodiment of the present invention will be described in conjunction with each device and its components in the communication system 1 . Each process of the method in the embodiment of the present invention can be adjusted according to the implementation situation, and is not limited to this.

FIG. 3 is a flowchart of a method for canceling a buffer status report according to an embodiment of the present invention. Referring to FIG. 3 , the processor 160 of the user equipment 100 may enable data duplication for the data unit of the Packet Data Convergence Protocol (PDCP) (step S310 ). Specifically, the data unit may be a protocol data unit (Protocol Data Unit, PDU) or other types of resource formats. For a certain radio bearer (corresponding to one PDCP entity), the data units of PDCP can be sent through one or more logical channels (Logical Channel, LCH) on the RLC entity. For example, FIG. 4A is a schematic diagram illustrating that data duplication is not implemented according to an embodiment of the present invention. Referring to FIG. 4A , taking the uplink as an example, two data units for a certain radio bearer RB1 are transmitted through logical channels LCH1 and LCH2 of two RLC entities RLC1 and RLC2 respectively. Under Carrier Aggregation (CA), the two component carriers (Component Carriers, CCs) CC1 and CC2 provided by one IAB-node 10 or IAB-provider 30 (if there is a decentralized unit function) can be respectively Send these two data units.

The difference from single data is that data replication can correspond a data unit (or the same type of traffic) of PDCP to a base station (eg, IAB-node 10 or IAB-provider 30) of the IAB mechanism. of two or more constituent carriers. For example, FIG. 4B is a schematic diagram illustrating implementing data replication according to an embodiment of the present invention. Referring to FIG. 4B, the RLC entity RLC1 and its logical channel LCHn may be responsible for a copy of a data unit (ie, a replicated data unit). In addition, the data unit and its copy will be transmitted through component carriers CC1, CC2 respectively (corresponding to a MAC entity MAC1 or a base station). It can be seen from this that the same data unit may be transmitted twice, one of which is via the logical channel LCHn of the RLC entity RLC1, and the other is via the logical channel LCH2 of the RLC entity RLC2. Thereby, reliability can be increased and time delay can be reduced.

It should be noted that FIG. 4A and FIG. 4B only take two RLC entities RLC1 and RLC2 as examples. In other embodiments, there may be more RLC entities, more logical channels or more component carriers. In addition, the aforementioned data unit of PDCP refers to a data protocol data unit (data PDU).

Furthermore, in order to let the IAB-node 10 or the IAB-provider 30 know that the user equipment 100 supports CA and IAB mechanisms. The processor 160 can notify the CA and IAB mechanisms through the MAC data unit (eg, PDU or other data unit format) on the data plane of the transmitter 130 to reduce control signaling costs.

FIG. 5 illustrates a data unit structure of a medium access control (MAC) according to an embodiment of the present invention. Referring to FIG. 5, the PDU of the MAC may include four types of sub-data units. The first sub-data unit 510 includes a sub-header (subheader) 511 and a service data unit (Service Data Unit, SDU) 513 . The second sub-data unit 530 includes a sub-header 531 and a fixed-length first control element (Control Element, CE) 533 . The third sub-data unit 550 includes a sub-header 551 and a second CE 553 of variable length. The fourth data unit 560 includes padding data.

And the user equipment 100 can notify the IAB-node 10 or the IAB-provider 30 about supporting/compliance with CA and IAB mechanisms through, for example, the first CE 533 or the second CE 553 . For example, the content to be notified is indicated in the Logical Channel Identity (LCID) field (filed). Table (1) is the value of the LCID field in the standard: Table (1) index LCID value index LCID value 0 Common Control Channel (CCCH) 57 Single entry PHR 1-32 Logical Channel ID 58 Cellular Radio Temporary Identity (C-RNTI) 33-51 reserve 59 short truncated BSR 52 CCCH 60 long truncated BSR 53 Recommended bit rate inquiry 61 Short BSR 54 Multiple entry (entry) power margin reporting (PHR) 62 long BSR 55 Confirmed by configuration grant 63 filling 56 Multi-entry PHR Among them, reserved places (eg, indexes 33-51) can be replaced with indications that conform to the CA and IAB mechanisms. It should be noted that, in other embodiments, the indication of compliance with the CA and IAB mechanisms may also be in other fields or other data in the header.

Next, the processor 160 triggers two or more buffer status reports for each PDCP data unit (step S330). Specifically, each buffer status report corresponds to a logical channel. FIG. 6 is a flowchart illustrating triggering a buffer status report according to an embodiment of the present invention. Referring to FIG. 6, the processor 160 confirms whether the CA and IAB mechanisms are triggered (step S610). For example, whether an indication of compliance with CA and IAB mechanisms has been sent. If the CA and IAB mechanisms are not triggered, the processor 160 only needs to execute a single BSR. For example, the data in FIG. 4A is not duplicated, and a data unit is only transmitted through one logical channel, so the BSR trigger of the MAC entity MAC1 only needs to trigger a single BSR for this data unit. If the CA and IAB mechanisms have been triggered, the processor 160 executes multiple BSRs (step S330). For example, the data in FIG. 4B is duplicated, and the data unit and its duplicate are transmitted through different logical channels, so the BSR trigger of the single MAC entity MAC1 must trigger the BSR for this data unit and its duplicate. That is to say, it is necessary to report to the base station the data volume of the data unit and its copy to be transmitted.

It is also worth noting that those buffer status reports correspond to one logical channel in different logical channel groups (LCGs). Taking FIG. 4B as an example, the logical channel LCH2 and the logical channel LCHn belong to different logical channel groups respectively. That is, the user equipment 100 reports the BSR based on the logical channel group. In some embodiments, logical channels of the same quality of service or priority may be classified into the same logical channel group, but may still vary according to actual needs.

It should be noted that FIG. 4B only takes one copy as an example, and in other embodiments, there may be more copies.

If uplink resources have been assigned, the processor 160 may send, through the transmitter 130, a BSR indicating the amount of data of the data unit and its replicas. This BSR may be a periodic or regular BSR. If the uplink resource has not been assigned, the processor 160 may send a Scheduling Request (SR) through the transmitter 130 to request resources to transmit the BSR.

In response to the transmission of the BSR, the processor 160 may determine whether the cancellation condition is met, and cancel the buffer status report on at least one of those logical channels according to the cancellation condition (step S350 ). Specifically, whether or not the uplink resource is obtained or not related to the cancellation condition. The processor 160 can determine whether the uplink resource assigned by the IAB-node 10 can accommodate the pending data unit (but may not be sufficient or sufficient to accommodate the BSR's MAC CE and its subheaders). If the uplink resource can accommodate the data unit to be transmitted (ie, the uplink resource has been acquired), the processor 160 may cancel the buffer status reporting on at least one of those logical channels. Taking FIG. 4B as an example, the processor 160 can cancel the triggered BSR on the logical channel LCHn by stopping the periodic BSR timer (periodicBSR-Timer) or the retransmission BSR timer (retxBSR-Timer). The processor 160 may also cancel the logical channel LCH2 in another logical channel group. Alternatively, the processor 160 cancels the logical channels of all logical channel groups.

In another embodiment, the processor 160 may also start a counter to record the number of times the BSR is transmitted for a particular resource unit. If the number of times recorded by the counter exceeds the threshold but the corresponding uplink resources have not been obtained (which may be due to channel problems or network failures) (ie, the uplink resources have not been obtained), the processor 160 may cancel the corresponding uplink resources in those logical channels. Buffer status returns on at least one.

FIG. 7 is a flowchart illustrating triggering a scheduling request according to an embodiment of the present invention. Referring to FIG. 7 , when the BSR is cancelled or there are still other data to be transmitted on the logical channel, the processor 160 may trigger a scheduling request (SR) (step S710 ). SR is used to request uplink resources for new transmissions. The processor 160 may receive the scheduling request configuration through the receiver 120, and correspond the scheduling request configuration to one or more logical channel-numerology pairs (step S730). A logical channel may correspond to one or more parameter sets (corresponding to subcarrier spaces or resource grids in the frequency domain, respectively). A parameter set corresponding to any logical channel can be called a logical channel-parameter set pair.

…(1)The processor 160 may configure and transmit the SR corresponding to the traffic to be transmitted according to the scheduling requirement (step S750). It is worth noting that the scheduling of the SR corresponding to the scheduling request configuration is obtained according to the capacity of the data unit of the MAC and the data type of the traffic to be transmitted. For example, the processor 160 may schedule a plurality of SRs for different traffic based on an Unbounded Knapsack solution. It is assumed that the user equipment 100 receives a MAC PDU of a given specific capacity size C , and intends to place m types of scheduling request configurations (corresponding to different data types, and related to such as Channel Quality Indicator (CQI) or other priority indicators). Furthermore, assume that the i-th type of traffic has replicated data (ie, a copy derived using the aforementioned data replication mechanism), the i-th type of data type priority p[i] and its data size w[i] ( i , C , m , p[i] , and w[i] can be positive integers, and an unlimited number of copies of each type can be assumed). A message occupies one MAC SDU. For i from 1 to m , it is possible to determine how many _xi of type i traffic can be selected into the MAC PDU to obtain the maximum benefit without exceeding the capacity size C (for example, the higher the priority The better, and the lower the priority, the worse):

…(1)

In other embodiments, the SR schedule may also be derived from other optimal solutions. In some embodiments, the user equipment 100 can also change the service type of the traffic (eg, Enhanced Mobile Broadband (eMBB), Massive Machine-Type Communications (mMTC), Ultra Reliable Low Latency Communications (Ultra Reliable Low Latency Communications, URLLC), fifth generation (5G) or other generation mobile communication technologies) is reported to the IAB-node 10 or the IAB-provider 30 .

Next, the processor 160 determines whether the transmission times of the SR (eg, SR_counter) exceeds the upper limit of the transmission times (eg, dsr-TransMax) (step S770 ). If the number of transmissions has not exceeded the upper limit of the number of transmissions and an uplink resource grant (eg, an uplink grant (UL grant)) has not been received, the processor 160 resends the SR (returning to step S710 ). If the number of transmissions exceeds the upper limit of the number of transmissions, the processor 160 determines that the connection with the IAB-node 10 is lost or out of synchronization, and starts a random access (RA) procedure accordingly (step S790 ).

It can be seen from this that the embodiment of the present invention can provide a cancellation mechanism for multiple BSRs under the CA and IAB mechanisms. For the IAB mechanism, enhanced backhaul access multiplexing, multiple connectivity and enhanced quality of service over multiple hops can also be provided.

FIG. 8 is a schematic diagram of a communication system 1 according to an embodiment of the present invention. Referring to FIG. 8, for the architecture applying the IAB mechanism, the IAB-node 10 in the communication system 1 may include a gNB function 11, a user plane function (UPF) 13 and a mobile terminal (MT) function 15, and the IAB - The supplier 30 may include the gNB function 31 and the UPF function 35. Thereby, a PDU session 23 for a specific radio bearer 21 can be connected to an IAB-provider 30 through one or more IAB-nodes 10 . In addition, embodiments of the present invention provide a hardware controller capable of running a Network Functions Virtualization Infrastructure (NFVI) manager and virtualization software. The network function virtualization platform can apply carrier-grade functions to manage or monitor platform components, recover abnormal errors and provide effective information security management.

To sum up, in the user equipment and the method for canceling the buffer status report according to the embodiment of the present invention, under the condition that the IAB-node provides the CA condition, the data level data unit is used to report that the condition is met, so as to reduce the signaling cost. In addition, the embodiments of the present invention can efficiently report multiple BSR patterns in the same MAC entity. The embodiments of the present invention also perform MAC SDU/SR scheduling in advance for the NR user equipment, thereby increasing the success rate of sending SR after the user equipment cancels the BSR, thereby reducing the time delay of uplink data.

Although the present invention has been disclosed above by the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the scope of the appended patent application.

1: Communication system 10:IAB-Node 30:IAB-Supplier 50: Core Network Entities 100: User Equipment AL: access link BL: Backhaul link 120: Receiver 130: Teleporter 140: Analog to Digital and Digital to Analog Converters 150: Storage 160: Processor S310~S350, S310~S630, S710~S790: Steps RB1: Radio Bearer PDCP1: PDCP entity RLC1, RLC2: RLC entities LCH1, LCH2, LCHn: logical channel MAC1: MAC entity 510: First sub-data unit 511, 531, 551: Subheaders 513: Service Data Unit 530: Second sub-data unit 533: First Control Element 550: Third sub-data unit 553: Second Control Element 560: Fourth sub-data unit 11, 31: gNB function 13, 35: UPF function 15: MT function 21: Bearing 23: Packet data unit chat

FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present invention. FIG. 2 is a block diagram of components of a user equipment according to an embodiment of the present invention. FIG. 3 is a flowchart of a method for canceling a buffer status report according to an embodiment of the present invention. FIG. 4A is a schematic diagram illustrating that data duplication is not implemented according to an embodiment of the present invention. FIG. 4B is a schematic diagram illustrating implementing data replication according to an embodiment of the present invention. FIG. 5 illustrates a data unit structure of Media Access Control according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating triggering a buffer status report according to an embodiment of the present invention. FIG. 7 is a flowchart illustrating triggering a scheduling request according to an embodiment of the present invention. FIG. 8 is a schematic diagram of a communication system according to an embodiment of the present invention.

S310~S350: Steps

Claims (10)

A buffer status report (Buffer Status Report, BSR) cancellation method is applicable to a user equipment, and the buffer status report cancellation method includes: A data duplication (data duplication) is enabled for at least a first data unit of a Packet Data Convergence Protocol (PDCP), wherein the data duplication is a The first data unit corresponds to at least two Component Carriers (CCs) provided by a base station of an Integrated Access and Backhaul (IAB) mechanism; triggering at least two buffer status reports for each of the first data units, wherein each of the buffer status reports corresponds to a logical channel (LCH); and The buffer status reporting on at least one of the at least two logical channels is cancelled according to a cancellation condition. The method for canceling a buffer status report according to claim 1, wherein the at least two buffer status reports respectively correspond to one of the logical channels in different logical channel groups (LCGs). The buffer status report cancellation method according to claim 1, wherein the cancellation condition is related to whether uplink resources are obtained or not, and the step of triggering at least two buffer status reports further comprises: judging that the assigned uplink resource accommodates a first data unit to be transmitted; and Canceling buffer status reporting on at least one of the at least two logical channels. The method for canceling a buffer status report according to claim 1, wherein the step of enabling the data replication for the at least one first data unit comprises: Compliant with the carrier aggregation and the integrated access and posthaul mechanism is notified through the second data unit of the Media Access Control (MAC) on the data plane. The method for canceling the buffer status report as described in request item 1, further comprising: receiving a Scheduling Request (SR) configuration, wherein the scheduling request configuration is derived according to the capacity of the second data unit of the MAC and the data type of the traffic to be transmitted; and The configuration transmits at least one scheduling request corresponding to the to-be-transmitted traffic according to the scheduling request. A user equipment comprising: a transmitter, which transmits the signal; a processor coupled to the transmitter and configured to: A data replication is enabled for at least a first data unit of a packet data aggregation protocol, wherein the data replication is to correspond a first data unit to a base station of an integrated access and posthaul mechanism under a carrier aggregation. Provided at least two component carriers; triggering at least two buffer status reports for each of the first data units, wherein each of the buffer status reports corresponds to a logical channel, and transmitting at least two of the buffer status reports through the transmitter; and The buffer status reporting on at least one of the at least two logical channels is cancelled according to a cancellation condition. The user equipment of claim 6, wherein the at least two buffer status reports respectively correspond to one of the logical channels in different logical channel groups. The user equipment of claim 6, wherein the cancellation condition is related to expiration of a timer, the timer is related to radio resource acquisition, and the processor is further configured to: start the timer; and It is judged that the timer has expired, and the buffer status report on at least one of the at least two logical channels is cancelled. The user equipment of claim 6, wherein the processor is further configured to: A second data unit notification via the transmitter's media access control at the data level conforms to the carrier aggregation and the integrated access and posthaul mechanism. The user equipment according to claim 6, further comprising: a receiver coupled to the processor and receiving the signal, wherein the processor is further configured to: receiving, through the receiver, a scheduling request configuration, wherein the scheduling request configuration is derived according to the capacity of the second data unit of the MAC and the data type of the traffic to be transmitted; and At least one scheduling request corresponding to the to-be-transmitted traffic is transmitted through the transmitter according to the scheduling request configuration.

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