WO2022006781A1 - Reassembly timer starting method, configuration method and apparatus, and device and medium - Google Patents

Abstract

Disclosed are a reassembly timer starting method, an apparatus, a device, and a storage medium, relating to the field of communications. The method comprises: a terminal device receiving a first RLC PDU from a MAC layer, with the first RLC PDU corresponding to an RLC SDU segment; when the first RLC PDU satisfies a starting condition for a reassembly offset timer, and both the reassembly offset timer and the reassembly timer are not started, starting the reassembly offset timer; and when the reassembly offset timer expires, starting the reassembly timer.

Description

Start-up method, configuration method, apparatus, device and medium of reassembly timer technical field

The present application relates to the field of wireless communication, and in particular, to a method, configuration method, apparatus, device and medium for starting a reassembly timer.

Background technique

Each logical channel of a user equipment (Use Equipment, UE) has a Radio Link Control (Radio Link Control, RLC) entity. The RLC entity has the function of segmentation and reassembly of RLC SDUs.

The RLC entity of the first UE on the transmitting side will divide the RLC SDU into multiple RLC SDU segments; the RLC entity of the second UE on the receiving side will reassemble the multiple RLC SDU segments in order to restore the original RLC SDU and handed over to the upper layer (PDCP layer).

Since different RLC SDU segments of the same RLC SDU may arrive at the second UE out of sequence, a reassembly timer (t-Reassembly) is set in the second UE to control the time for the second UE to reassemble the RLC SDU. However, under the non-terrestrial network (Non Terrestrial Network, NTN) technology, due to the high communication delay between the UE and the network device, the reassembly timer in the related art cannot work normally.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a method for starting a reorganization timer, a method for configuring the timer, an apparatus, a device, and a storage medium. The technical solution is as follows.

According to an aspect of the present application, a method for starting a reassembly timer is provided, which is used in an RLC entity, and the method includes:

Receive a first RLC PDU from the MAC layer, the first RLC PDU corresponds to an RLC SDU segment;

When the first RLC PDU satisfies the first start condition of the reassembly offset timer, and neither the reassembly offset timer nor the reassembly timer is started, start the reassembly offset timer;

When the reassembly offset timer expires, the reassembly timer is started.

According to one aspect of the present application, a configuration method is provided, the method comprising:

The network device sends configuration information to the terminal, where the configuration information is used to configure the timing duration of the reassembly offset timer of the RLC entity. Or, the configuration information is used to configure the reassembly offset timer and the timing duration of the reassembly timer of the RLC entity

According to an aspect of the present application, an RLC entity device is provided, wherein the device includes:

a receiving module, configured to receive a first RLC PDU from the MAC layer, where the first RLC PDU corresponds to an RLC SDU segment;

A timer module, configured to start the reorganization when the first RLC PDU satisfies the first start condition of the reassembly offset timer, and neither the reassembly offset timer nor the reassembly timer is started an offset timer; when the reassembly offset timer expires, the reassembly timer is started.

According to one aspect of the present application, a configuration apparatus is provided, the apparatus comprising:

A sending module, configured to send configuration information to the terminal, where the configuration information is used to configure the timing duration of the reassembly offset timer of the RLC entity

According to one aspect of the present application, a terminal is provided, the terminal comprising: a processor; a transceiver connected to the processor; a memory for storing executable instructions of the processor; wherein the processing The processor is configured to load and execute the executable instructions to implement the method for starting the reassembly timer as described in the above aspects.

According to one aspect of the present application, a network device is provided, the network device comprising: a processor; a transceiver connected to the processor; a memory for storing executable instructions of the processor; wherein the The processor is configured to load and execute the executable instructions to implement the configuration method as described in the above aspects.

According to one aspect of the present application, a computer-readable storage medium is provided, and executable instructions are stored in the readable storage medium, and the executable instructions are loaded and executed by the processor to implement the above-mentioned aspects. The start method of the reassembly timer.

According to one aspect of the present application, there is provided a computer program product, the readable storage medium stores executable instructions, the executable instructions are loaded and executed by the processor to implement the reorganization as described in the above aspect Start method or configuration method of the timer.

According to one aspect of the present application, a chip is provided, the chip is configured to implement the method for starting or configuring the reorganization timer as described in the above aspects.

The technical solutions provided by the embodiments of the present application include at least the following beneficial effects:

The network device configures the timer length of the reassembly offset timer of the RLC entity to the terminal, and the terminal adds a reassembly offset timer with the timer length, so that the reassembly waiting time of the RLC entity becomes the reassembly offset timer and the reassembly offset timer. The sum of the timers, thus avoiding the problem that the reorganization waiting time of the RLC entity is too short and the RLC SDU cannot be received normally. This embodiment can provide backward compatibility of the technical solution under the condition that the original design structure of the reassembly timer remains unchanged as much as possible.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a block diagram of a communication system provided by an exemplary embodiment of the present application;

2 is a flowchart of a method for starting a reassembly timer provided by an exemplary embodiment of the present application;

3 is a schematic structural diagram of an RLC PDU provided by an exemplary embodiment of the present application;

4 is a flowchart of a configuration method provided by an exemplary embodiment of the present application;

5 is a flowchart of a method for starting a reassembly timer provided by an exemplary embodiment of the present application;

6 is a time-frequency schematic diagram of a method for starting a reorganization timer provided by an exemplary embodiment of the present application;

7 is a flowchart of a method for starting a reorganization timer provided by an exemplary embodiment of the present application;

8 is a time-frequency schematic diagram of a method for starting a reorganization timer provided by an exemplary embodiment of the present application;

9 is a block diagram of an apparatus for starting a reorganization timer provided by an exemplary embodiment of the present application;

FIG. 10 is a block diagram of a configuration apparatus provided by an exemplary embodiment of the present application;

FIG. 11 is a schematic structural diagram of a communication device provided by an exemplary embodiment of the present application.

detailed description

In order to make the objectives, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

Non-Terrestrial Network (NTN)

Currently 3GPP is studying NTN technology, which generally uses satellite communication to provide communication services to terrestrial users. Compared with terrestrial cellular network communication, satellite communication has many unique advantages. First of all, satellite communication is not limited by the user's geographical area. For example, general terrestrial communication cannot cover areas such as oceans, mountains, deserts, etc. where communication equipment cannot be set up or cannot be covered due to sparse population. For satellite communication, due to a single Satellites can cover a large ground, and satellites can orbit around the earth, so theoretically every corner of the earth can be covered by satellite communications. Secondly, satellite communication has great social value. Satellite communications can be covered at low cost in remote mountainous areas and poor and backward countries or regions, so that people in these regions can enjoy advanced voice communication and mobile Internet technologies, which is conducive to narrowing the digital divide with developed regions and promoting development in these areas. Thirdly, the satellite communication distance is long, and the communication cost does not increase significantly when the communication distance increases; finally, the satellite communication has high stability and is not limited by natural disasters.

Communication satellites are classified into Low-Earth Orbit (LEO) satellites, Medium-Earth Orbit (MEO) satellites, Geostationary Earth Orbit (GEO) satellites, and highly elliptical orbits according to their orbital altitudes. (High Elliptical Orbit, HEO) satellites, etc. The main research at this stage is LEO and GEO.

1. LEO

The altitude range of low-orbit satellites is 500km to 1500km, and the corresponding orbital period is about 1.5 hours to 2 hours. The signal propagation delay of single-hop communication between users is generally less than 20ms. The maximum satellite viewing time is 20 minutes. The signal propagation distance is short, the link loss is small, and the transmit power requirements of the user terminal are not high.

2. GEO

A satellite in geosynchronous orbit with an orbital altitude of 35,786km and a 24-hour rotation period around the earth. The signal propagation delay of single-hop communication between users is generally 250ms.

In order to ensure the coverage of satellites and improve the system capacity of the entire satellite communication system, satellites use multiple beams to cover the ground. A satellite can form dozens or even hundreds of beams to cover the ground; a satellite beam can cover tens to hundreds of kilometers in diameter. ground area.

New Radio Hybrid Automatic Repeat Request (NR HARQ) mechanism

NR has a two-level retransmission mechanism: the HARQ mechanism of the Medium Access Control (MAC) layer and the ARQ mechanism of the Radio Link Control (Radio Link Control, RLC) layer. The retransmission of lost or erroneous data is mainly handled by the HARQ mechanism of the MAC layer, supplemented by the retransmission function of the RLC layer. The HARQ mechanism of the MAC layer can provide fast retransmission, and the automatic repeat request (Automatic Repeat reQuest, ARQ) mechanism of the RLC layer can provide reliable data transmission.

HARQ uses the Stop-and-Wait Protocol (Stop-and-Wait Protocol) to send data. In the stop-and-wait protocol, after the sender sends a TB, it stops and waits for an acknowledgment. In this way, the sender stops and waits for an acknowledgment after each transmission, resulting in low user throughput. Therefore, NR uses multiple parallel HARQ processes. When one HARQ process is waiting for acknowledgment information, the sender can use another HARQ process to continue sending data. These HARQ processes collectively form a HARQ entity, which incorporates a stop-and-wait protocol, allowing data to be transmitted continuously. HARQ is divided into uplink HARQ and downlink HARQ. Uplink HARQ is for uplink data transmission, and downlink HARQ is for downlink data transmission. The two are independent of each other.

Based on the provisions of the current NR protocol, the terminal has its own HARQ entity corresponding to each serving cell. Each HARQ entity maintains a set of parallel downlink HARQ processes and a set of parallel uplink HARQ processes. Currently, each uplink and downlink carrier supports a maximum of 16 HARQ processes. The base station may indicate the maximum number of HARQ processes to the UE through RRC signaling semi-static configuration according to the network deployment situation. If the network does not provide corresponding configuration parameters, the default number of HARQ processes in downlink is 8, and the maximum number of HARQ processes supported by each uplink carrier is always 16. Each HARQ process corresponds to a HARQ process ID. For downlink, BCCH uses a dedicated broadcast HARQ process. For uplink, Msg3 transmission in random process uses HARQ ID 0.

For terminals that do not support downlink space division multiplexing, each downlink HARQ process can only process one Transport Block (TB) at the same time; for terminals that support downlink space division multiplexing, each downlink HARQ process can process one transport block simultaneously. or 2 TB. Each uplink HARQ process of the terminal simultaneously processes 1 TB.

HARQ is divided into two categories: synchronous and asynchronous in the time domain, and non-adaptive and adaptive in the frequency domain. Both the NR uplink and downlink use the asynchronous adaptive HARQ mechanism. Asynchronous HARQ, that is, retransmission can occur at any time, and the time interval between retransmission of the same TB and the previous transmission is not fixed. Adaptive HARQ can change the frequency domain resources and MCS used for retransmission.

NR RLC segmentation and reassembly RLC service data unit (Service Data Unit, SDU) function

Each logical channel of the UE has one RLC entity. An RLC entity can be configured as one of three modes: transparent transmission mode (TM), unacknowledged mode (un Acknowledged Mode, UM), and acknowledged mode (Acknowledged Mode, AM).

TM: corresponds to the TM RLC entity. This mode can be considered as an empty RLC, because only the transparent transmission function of data is provided in this mode.

UM: corresponds to the UM RLC entity. This mode provides all RLC functions except retransmission, re-segmentation, duplicate packet detection, and protocol error detection, thus providing an unreliable transmission service.

AM: For AM RLC entities. This mode provides a reliable transmission service through error detection and retransmission. This mode supports all functions of RLC.

For UM and AM, fragmentation and reassembly functions of RLC SDUs can be supported. Since the resource size of each transmission is determined by the MAC scheduler, its size usually cannot completely match the size of the RLC SDU, so the sender needs to segment the RLC SDU so that it matches the size indicated by the MAC layer. Correspondingly, at the receiving end, the previously segmented RLC SDU needs to be reassembled, so as to restore the original RLC SDU and deliver it to the upper layer (PDCP layer).

FIG. 1 shows a schematic diagram of an implementation environment provided by an embodiment of the present application, and the implementation environment describes a satellite access network (Satellite access network) in the NTN technology. The implementation environment includes a terminal 01 , a satellite 02 , a gateway 03 and a core network 04 .

In the NTN technology, there may be multiple terminals 01 , and the multiple terminals 01 may all be in communication connection with the satellite 02 , and FIG. 1 only schematically shows the situation of one terminal 01 . In addition, there may be multiple satellites 02, and the multiple satellites 02 are connected through inter-satellite/aerial links (ISL), and FIG. 1 only schematically shows a situation of one satellite 02.

In the NTN technology, a terminal can also be called an NTN terminal. The NTN terminal can be a terminal defined by 3GPP, or when the satellite does not directly serve a terminal defined by 3GPP, the NTN terminal can be a terminal specific to the satellite system. . The terminal may be a user equipment (User Equipment, UE).

The terminal 01 and the satellite 02 are connected through a service link (service link) communication, and the service link refers to the radio link (radio link) between the terminal 01 and the satellite 02. In addition, the terminal 01 can also support wireless communication connection with the terrestrial access network.

Satellite 02 may also be referred to as an airborne platform or space/airborne platform, enabling bent pipe or regenerative payload configurations.

A gateway (Gateway) 03 is used to connect the satellite (or aviation access network) 02 and the core network. The gateway 03 and the satellite 02 are connected through feeder links.

In the implementation environment provided by the embodiment of the present application, the satellite 02 is used to connect the terminal 01 to the core network 04. Of course, other optional implementation environments may also include a base station, which is not limited in the embodiment of the present application.

FIG. 2 shows a flowchart of a method for starting a reassembly timer provided by an exemplary embodiment of the present application. This embodiment is exemplified by the method being executed by the UE. Optionally, the method is performed by an RLC entity in a UE serving as a receiver (receiving UE for short). The method includes:

Step 202, receive the first RLC PDU from the MAC layer, and the first RLC PDU corresponds to an RLC SDU segment;

The data received by the RLC entity from the PDCP layer, or the data sent to the PDCP layer is called RLC SDU (or PDCP PDU). The data received by the RLC entity from the MAC layer, or the data sent to the MAC layer is called RLC PDU (or MAC SDU).

In the case where the UE serving as the sender (referred to as the sending UE) does not segment the RLC SDU, one RLC PDU corresponds to one RLC SDU. In the case where the sending UE segments the RLC SDU, one RLC PDU corresponds to one RLC SDU segment.

Exemplarily, the RLC PDU includes: an RLC header and an RLC SDU; or, an RLC header and an RLC SDU segment. As shown in Figure 3, assuming that the RLC SDU with SN=X is an unsegmented RLC SDU, the RLC SDU with SN=X+1 is segmented into two segments, where RLC PDU 0=RLC header+RLC SDU, RLC PDU 1=RLC header+RLC SDU segment 1, RLC PDU 2=RLC header+RLC SDU segment 2.

The RLC entity receiving the UE receives the first RLC PDU from the MAC layer, and the first RLC PDU corresponds to one RLC SDU segment.

Step 204, when the first RLC PDU satisfies the first start condition of the reassembly offset timer, and the reassembly offset timer and the reassembly timer are not started, start the reassembly offset timer;

In this embodiment, in addition to the reassembly timer (t-Reassembly), a reassembly offset timer (t-Reassembly offset) is additionally set.

When the start conditions are met and neither the reassembly offset timer nor the reassembly timer has been started, the reassembly offset timer is started first. Optionally, the first start condition includes at least one of the following conditions:

1. At least one bit that belongs to the first RLC SDU corresponding to the first RLC PDU and is located before the first RLC PDU has not been received;

For example, the first RLC SDU is divided into three RLC SDU segments, the first RLC PDU corresponds to RLC SDU segment 3, and there are still RLC SDU segment 1 and RLC SDU segment 2 that have not been received.

2. At least one bit of the second RLC SDU before the first RLC SDU has not been received.

For example, the first RLC SDU is an RLC SDU with SN=X, and one RLC SDU segment corresponding to the first RLC SDU has been received, but there is at least one bit in the RLC SDU with SN=X-1 that has not been received.

The timing duration of the reassembly offset timer is predefined by the communication protocol or preconfigured by the network device. The timing duration of the reassembly offset timer is greater than the round trip transmission time (Round Trip Time, RTT), where the RTT is the RTT when the communication signal is transmitted between the terminal and the network device (satellite). When this embodiment is applied to an NTN scenario, the network device may be a satellite.

In some embodiments, the timing duration of the reassembly offset timer is greater than or equal to: RTT*max_HARQ_reTx_number, where max_HARQ_reTx_number is the maximum number of retransmissions corresponding to the HARQ mechanism of the MAC layer.

Step 206, in the case that the reassembly offset timer expires, start the reassembly timer.

To sum up, the method provided in this embodiment, aiming at the problem of long RTT between the terminal and the network device in the NTN system, increases and sets the reassembly offset timer, so that the reorganization waiting time of the RLC entity becomes the reassembly offset. The sum of the timer and the reassembly timer, thus avoiding the problem that the reorganization waiting time of the RLC entity is too short and the RLC SDU cannot be received normally. This embodiment can provide backward compatibility of the technical solution under the condition that the original design structure of the reassembly timer remains unchanged as much as possible.

FIG. 4 shows a flowchart of a configuration method provided by an exemplary embodiment of the present application. This embodiment is exemplified by the method being executed by a network device. The network equipment can be a terrestrial base station or a satellite base station. The method includes:

Step 402, the network device sends configuration information to the terminal, where the configuration information is used to configure the timing duration of the reassembly offset timer of the RLC entity;

Optionally, the configuration information is RRC configuration information. The reassembly offset timer is a timer used with the reassembly timer and started before the reassembly timer.

The timing duration of the reassembly offset timer is greater than the RTT, which is the RTT when the communication signal is transmitted between the terminal and the network device (satellite). When this embodiment is applied to an NTN scenario, the network device may be a satellite.

In some embodiments, the configuration information is UE-level configuration, applicable to all radio bearers in the UE; in other embodiments, the configuration information is bearer-level configuration, applicable to designated radio bearers in the UE, and designated radio bearers part of all radio bearers.

Step 404, the terminal receives the configuration information sent by the network device.

The terminal configures the reassembly offset timer in the RLC entity according to the configuration information. Optionally, the terminal receives the RRC configuration information sent by the network device, extracts the timer duration from the RRC configuration information, and the terminal configures the reassembly offset timer in the RLC entity according to the timer duration.

To sum up, in the method provided in this embodiment, the network device configures the timer duration of the reassembly offset timer of the RLC entity to the terminal, and the terminal additionally sets the reassembly offset timer with the timer duration, so that the RLC entity's reassembly offset timer The reassembly waiting time becomes the sum of the reassembly offset timer and the reassembly timer, thereby avoiding the problem that the reorganization waiting time of the RLC entity is too short and cannot receive the RLC SDU normally. This embodiment can provide backward compatibility of the technical solution under the condition that the original design structure of the reassembly timer remains unchanged as much as possible.

The above method, when executed by the RLC entity, is applicable to UM mode or AM mode.

In the UM mode, at least one of an uplink UM RLC sending entity and a downlink UM RLC receiving entity is set in the UE. The above method is performed by the downlink UM RLC receiving entity.

In the AM mode, an AM RLC entity is set in the UE, and the AM RLC entity is divided into a sending side and a receiving side.

UM mode:

FIG. 5 shows a flowchart of a method for starting a reassembly timer provided by an exemplary embodiment of the present application. This embodiment is exemplified by the method being performed by the UE (RLC entity). Optionally, the RLC entity in the UE includes: a downlink UM RLC receiving entity. The method includes:

Step 501, the UE receives the configuration information sent by the network device;

The configuration information is at least used to configure the timer duration of the reassembly offset timer in the RLC entity.

The network device sends RRC configuration information to the UE, where the RRC configuration information is used to configure the RLC function, or the function of the RLC entity. The UE receives the RRC configuration information sent by the network device.

Step 502, the UE configures the RLC function for each radio bearer according to the configuration information;

The UE configures the RLC function for each radio bearer according to the RRC configuration information. This step includes at least one of the following substeps:

1. Configure at least one radio bearer as a UM mode, where the UM mode includes: any one of a bidirectional UM mode and a unidirectional UM mode (only downlink);

2. In the two-way UM mode, one uplink UM RLC sending entity and one downlink UM RLC receiving entity are set in the radio bearer; in the one-way UM mode, one downlink UM RLC receiving entity is set in the radio bearer. The UE sets the RLC reassembly timer t-Reassembly in the downlink UM RLC receiving entity.

3. Set the RLC reassembly offset timer t-Reassembly offset in the downlink UM RLC receiving entity.

The configuration information carries the timer duration (or the start time offset of the reassembly timer). Optionally, the timer duration t-Reassembly offset>=RTT*max_HARQ_reTx_number. The RTT is the RTT when the communication signal is transmitted between the terminal and the network device (satellite). max_HARQ_reTx_number is the maximum number of retransmissions corresponding to the HARQ mechanism of the MAC layer.

In the case of UE-level configuration (applicable to all radio bearers), if a downlink UM RLC receiving entity is set in the radio bearer, the UE sets the RLC reassembly offset timer t-Reassembly offset for the downlink UMRLC receiving entity according to the timer duration. In the case of the radio bearer level configuration (applicable to the designated radio bearer), and the designated radio bearer is set with a downlink UM RLC receiving entity, the UE sets the RLC reassembly offset timer t- for the downlink UM RLC receiving entity according to the timer duration. Reassembly offset.

Step 503, the UE maintains three variables for each downlink UM RLC receiving entity:

The downlink UM RLC receiving entity has the function of packet reassembly of RLC SDUs. A reassembly receiving window is set in the downlink UM RLC receiving entity. Optionally, the downlink UM RLC receiving entity maintains the following three variables for the reorganization receiving window: a first variable, a second variable and a third variable.

Take the first variable as RX_Next_Highest, the second variable as RX_Next_Reassembly, and the third variable as RX_Timer_Trigger as an example:

RX_Next_Highest is the SN next to the SN of the second RLC PDU with the largest SN in the received RLC PDUs. The initial value of this variable is 0.

RX_Timer_Trigger is the SN next to the SN that triggers the start of the t-Reassembly offset (or t-Reassembly). The initial value of this variable is empty. When t-Reassembly offset (or t-Reassembly) is started, it indicates that there are RLC PDUs smaller than this variable that have not been received, and it is necessary to wait for PDUs for reassembly.

RX_Next_Reassembly is the minimum SN within the reassembly receive window. That is, within the reassembly receiving window, the SN of the earliest RLC PDU currently waiting for reassembly. The initial value of this variable is 0, and the downlink UM RLC entity assumes by default that all RLC SDUs with SN smaller than this variable have been successfully received or discarded.

Step 504, (a certain) downlink UM RLC receiving entity in the UE receives the first RLC PDU from the MAC layer, and the first RLC PDU corresponds to an RLC SDU segment;

If the downlink UM RLC receiving entity receives an RLC PDU that does not contain an SN, the RLC PDU corresponds to an unsegmented RLC SDU, removes the RLC header of the RLC PDU to obtain the RLC SDU, and sends the RLC SDU to the upper layer.

If the downlink UM RLC receiving entity receives a UMD PDU from the MAC layer, and the header of the UMD PDU contains an SN, indicating that the UMD PDU corresponds to an RLC SDU segment, and the SN is greater than or equal to RX_Next_Reassembly, the received The UMD PDU is placed in the receive buffer.

The SN is the sequence number of the segmented RLC SDU, and different RLC SDU segments have different SNs. When one RLC SDU is segmented into at least two RLC SDU segments, the at least two RLC SDU segments have the same SN. In addition, the at least two RLC SDU segments also have other information for identifying the segment order and segment start position, and the other information is used to reassemble the at least two RLC SDU segments into RLC SDUs.

The UE performs at least one of steps 505 to 508:

Step 505, in the case that neither the reorganization offset timer nor the reorganization timer is running, and any one of the following first start conditions is met, start the reorganization offset timer;

The first start condition of the reassembly offset timer includes any one of the following two conditions:

Start condition 1: if RX_Next_Highest>RX_Next_Reassembly+1;

Start Condition 2: If RX_Next_Highest=RX_Next_Reassembly+1, and for the first RLC SDU with SN equal to RX_Next_Reassembly, there is at least one unreceived bit segment before the last bit of the first RLC SDU received;

Among them, RX_Next_Highest is the next SN of the SN of the second RLC PDU with the largest SN in the received RLC PDUs, and RX_Next_Reassembly is the minimum SN in the reassembly receiving window.

Step 506, when the reassembly offset timer times out, start the reassembly timer;

Step 507, when the reassembly timer times out and the following first start condition is satisfied, start the reassembly offset timer, and set RX_Timer_Trigger to RX_Next_Highest;

When the reassembly timer expires, the downlink UM RLC receiving entity performs the following operations:

1) Update RX_Next_Reassembly to the first SN that is not less than RX_Timer_Trigger and has not completed the reassembly.

2) discarding all segments whose corresponding SN is less than the updated RX_Next_Reassembly;

3) If any one of the start conditions of the reassembly offset timer is satisfied, start the t-Reassembly offset again, and set RX_Timer_Trigger to RX_Next_Highest.

In step 508, when the reorganization offset timer is running, and any one of the following stop conditions is satisfied, stop and reset the reorganization offset timer; or, when the reorganization timer is running, the following stop conditions are satisfied: In the case of any of the conditions, the reassembly timer is stopped and reset.

The stop condition includes any one of the following three conditions:

Stop condition 1: if RX_Timer_Trigger<=RX_Next_Reassembly;

Stop condition 2: If RX_Timer_Trigger falls outside the reassembly receive window, and RX_Timer_Trigger is not equal to RX_Next_Highest;

Stop condition 3: If RX_Next_Highest=RX_Next_Reassembly+1, and for the first RLC SDU corresponding to SN=RX_Next_Reassembly, there is no unreceived bit segment before the last bit of the received first RLC SDU;

Among them, RX_Next_Highest is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, RX_Timer_Trigger is the next SN of the SN that triggers the start of the reassembly offset timer, and RX_Next_Reassembly is the smallest SN in the reassembly receiving window. SN.

To sum up, in the method provided by this embodiment, the reorganization offset timer is added and set, so that the reorganization waiting time of the RLC entity becomes the sum of the reorganization offset timer and the reassembly timer, thereby avoiding the reorganization waiting time of the RLC entity. The problem is that the duration is too short to receive the RLC SDU normally. This embodiment can provide backward compatibility of the technical solution under the condition that the original design structure of the reassembly timer remains unchanged as much as possible.

In the method provided by this embodiment, for the UM receiving mode, the start condition and stop condition of the reassembly offset timer are also set, so that the reassembly offset timer can be turned on or off reasonably, and the backward compatibility of the technical solution is improved. .

With reference to FIG. 6, it is assumed that the downlink UM RLC receiving entity maintains the following three variables for the reassembly receiving window: RX_Next_Reassembly, RX_Timer_Trigger and RX_Next_Highest are all initial states.

1. The network device sends the UMD PDU1 to the UE, but the UE fails to receive the UMD PDU1 (SN=X) successfully, and feeds back a negative feedback (NACK) to the network device.

2. The network device sends the UMD PDU2 to the UE, and the UE successfully receives the UMD PDU2 (SN=X), and feeds back an acknowledgment feedback (ACK) to the network device. Since UMD PDU2 corresponds to segment 2 of RLC SDU n, SN=X of RLC SDU n. After the UE successfully receives the UMD PDU2, it puts the UMD PDU2 into the receiving buffer. The three state variables at this time are:

RX_Next_Highest=x+1, RN_Timer_Trigger=0, RX_Next_Reassembly=x.

Since RX_Next_Highest=RX_Next_Reassembly+1=x+1, and the RLC SDUn of SN=x has a segment 1 before UMD PDU2 that has not been received, so the UE starts the reassembly offset timer t-Reassembly offset, the reassembly offset timing t-Reassembly offset = 3 RTTs.

At the same time, RN_Timer_Trigger=RX_Next_Highest=x+1 is set.

Then the three state variables at this time are:

RX_Next_Highest=x+1, RN_Timer_Trigger=x+1, RX_Next_Reassembly=x.

3. The network device sends the UMD PDU3 to the UE, and the UE successfully receives the UMD PDU3 and feeds back an acknowledgment feedback (ACK) to the network device. Since UMD PDU3 corresponds to RLC SDU n+1, RLC SDU n+1 is an unsplit RLC SDU and does not have an SN. Then the three state variables at this time are:

RX_Next_Highest=x+1, RN_Timer_Trigger=x+1, RX_Next_Reassembly=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, the RLC entity of the UE reports the RLC SDUn+1 to the MAC layer entity.

4. The network device sends the UMD PDU4 to the UE, and the UE successfully receives the UMD PDU4 (SN=X+1), and feeds back an acknowledgment feedback (ACK) to the network device. Since UMD PDU4 corresponds to segment 1 of RLC SDU n+2, the SN of RLC SDU n+2 is X+1. Then the three state variables at this time are:

RX_Next_Highest=x+2, RN_Timer_Trigger=x+1, RX_Next_Reassembly=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, UMD PDU2 and UMD PDU4 are buffered in the reassembly receiving window for reassembly.

5. The network device sends the UMD PDU5 to the UE, and the UE successfully receives the UMD PDU5 (SN=X+1), and feeds back an acknowledgment feedback (ACK) to the network device. Since UMD PDU5 corresponds to segment 1 of RLC SDU n+2, the SN of RLC SDU n+2 is X+1. Then the three state variables at this time are:

RX_Next_Highest=x+2, RN_Timer_Trigger=x+1, RX_Next_Reassembly=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, the two segments in UMD PDU4 and UMD PDU 5 are reorganized into RLC SDU n+2, and the RLC entity of the UE reports RLC SDUn+2 to the MAC layer entity. And UMD PDU2 is buffered in the reassembly receiving window waiting for reassembly.

6. The network device sends the UMD PDU1 to the UE again. The UE fails to receive the UMD PDU1 successfully (SN=X), and feeds back a negative feedback (NACK) to the network device. Since UMD PDU1 corresponds to segment 1 of RLC SDU n, SN=X of RLC SDU n. Then the three state variables at this time are:

RX_Next_Highest=x+2, RN_Timer_Trigger=x+1, RX_Next_Reassembly=x.

Since RX_Next_Highest>RX_Next_Reassembly+1, and the reassembly offset timer t-Reassembly offset is running, continue to keep t-Reassembly offset running.

7. The network device sends the UMD PDU1 to the UE again. The UE fails to receive the UMD PDU1 (SN=X) successfully, and feeds back a negative feedback (NACK) to the network device. Since UMD PDU1 corresponds to segment 1 of RLC SDU n, SN=X of RLC SDU n. Then the three state variables at this time are:

RX_Next_Highest=x+2, RN_Timer_Trigger=x+1, RX_Next_Reassembly=x.

Since RX_Next_Highest>RX_Next_Reassembly+1, and the timer duration of the reassembly offset timer t-Reassembly offset expires, the UE continues to start the reassembly timer t-Reassembly to run.

8. When the reassembly timer t-Reassembly times out, update RX_Next_Reassembly to the first SN that is not less than RX_Timer_Trigger and has not yet completed the reassembly, that is, x+3. All segments whose corresponding SN is smaller than the updated RX_Next_Reassembly=x+3, that is, UMD PDU2, are discarded. Since any one of the first start conditions of the reassembly offset timer is no longer satisfied, the t-Reassembly offset is no longer started.

The above embodiment can be expressed as the following description:

Behavior when a UMD PDU is in the receive buffer

When a UMD PDU with SN=x is in the receive buffer, the UM RLC receiving entity shall:

1. If all bit fields of SN=x are received:

- Reassemble the RLC SDU from all bit fields of SN=X, remove the RLC header and submit the reassembled RLC SDU to the higher layers.

- If x=RX_Next_Reassembly, update RX_Next_Reassembly to: the next SN of the first SN that fails to be reassembled and delivered to the upper layer, the first SN is the current RX_Next_Reassembly.

2. Otherwise, if x is outside the reassembly receiving window, update RX_Next_Highest to x+1, and discard all UMDPDUs that fall outside the reassembly receiving window;

If RX_Next_Reassembly falls outside the reassembly receiving window, update RX_Next_Reassembly to the next SN of the second SN that fails to reassemble and deliver to the upper layer, and the second SN is (RX_Next_Highest-UM_Window_Size).

3. If the reassembly timer is running, or, if the reassembly offset timer is configured and the reassembly offset timer is running:

if RX_Timer_Trigger <= RX_Next_Reassembly; or,

If RX_Timer_Trigger is outside the reassembly receive window and RX_Timer_Trigger is not equal to RX_Next_Highest; or,

If RX_Next_Highest=RX_Next_Reassembly+1, and for the RLC SDU with SN=RX_Next_Reassembly, all bit fields before the last bit of the currently received RLC SDU have been received.

stop and reset the reassembly timer (if the reassembly timer is running), or, stop and reset the reassembly offset timer (if the reassembly offset timer is running),

4. If the reassembly offset timer does not run, and the reassembly timer does not run (including the case where the reassembly offset timer or the reassembly timer is stopped due to the above reasons), then if any of the following two conditions are met, then Start the reassembly offset timer with RX_Timer_Trigger set to RX_Next_Highest.

Condition 1: if RX_Next_Highest>RX_Next_Reassembly+1;

Condition 2: If RX_Next_Highest=RX_Next_Reassembly+1 and for the RLC SDU corresponding to SN=RX_Next_Reassembly, there is at least one unreceived Byte segment before the last bit of the currently received RLC SDU;

If the reassembly offset timer is configured, start the reassembly offset timer; otherwise, start the reassembly timer. Set RX_Timer_Trigger to RX_Next_Highest.

When the reassembly offset timer expires, the reassembly timer is started.

Behavior of reassembly timer timeout:

If the reassembly timer expires, the downlink UM RLC receiving entity performs the following operations:

Update RX_Next_Reassembly to the first SN that is not less than RX_Timer_Trigger and has not completed reassembly.

Discard all segments whose corresponding SN is less than the updated RX_Next_Reassembly;

If any of the following 2 conditions are met:

- Condition 1: RX_Next_Highest > RX_Next_Reassembly+1;

- Condition 2: If RX_Next_Highest=RX_Next_Reassembly+1 and for the RLC SDU corresponding to SN=RX_Next_Reassembly, there is at least one unreceived Byte segment before the last byte in the currently received segment of the RLC SDU;

Then, if the reassembly offset timer is configured, the reassembly offset timer is started, and RX_Timer_Trigger is set to RX_Next_Highest at the same time.

AM mode:

FIG. 7 shows a flowchart of a method for starting a reassembly timer provided by an exemplary embodiment of the present application. This embodiment is exemplified by the method being performed by the UE (RLC entity). Optionally, the RLC entity in the UE includes: a downlink AM RLC entity or a receiving side of the downlink AM RLC entity. The method includes:

Step 701, the UE receives the configuration information sent by the network device;

The configuration information is at least used to configure the timer duration of the reassembly offset timer in the RLC entity.

The network device sends RRC configuration information to the UE, where the RRC configuration information is used to configure the RLC function, or the function of the RLC entity. The UE receives the RRC configuration information sent by the network device.

Step 702, the UE configures the RLC function for each radio bearer according to the configuration information;

The UE configures the RLC function for each radio bearer according to the RRC configuration information. This step includes at least one of the following substeps:

1. Configure at least one radio bearer in AM mode;

2. In AM mode, one uplink AM RLC entity and one downlink AM RLC entity are set in the radio bearer. The UE sets the RLC reassembly timer t-Reassembly in the downlink UM RLC receiving entity.

3. Set the RLC reassembly offset timer t-Reassembly offset in the downlink AM RLC entity.

The configuration information carries the timer duration (or the start time offset of the reassembly timer). Optionally, the timer duration t-Reassembly offset>=RTT*max_HARQ_reTx_number. The RTT is the RTT when the communication signal is transmitted between the terminal and the network device (satellite). max_HARQ_reTx_number is the maximum number of retransmissions corresponding to the HARQ mechanism of the MAC layer.

In the case of UE-level configuration (applicable to all radio bearers), if a downlink AM RLC entity is set in the radio bearer, the UE sets the RLC reassembly offset timer t-Reassembly offset for the downlink AM RLC entity according to the timer duration. In the case of the radio bearer level configuration (applicable to the designated radio bearer), the designated radio bearer is set with a downlink AM RLC entity, then the UE sets the RLC reassembly offset timer t-Reassembly offset for the downlink AM RLC entity according to the timer duration .

Step 703, the UE maintains three variables for each downlink AM RLC entity:

The downlink AM RLC entity has the function of packet reassembly of RLC SDUs. A reassembly receiving window is set in the downlink AM RLC entity. Optionally, the downlink AM RLC entity maintains the following four variables for the reassembly receiving window: a first variable, a fourth variable, a fifth variable and a sixth variable.

Take the first variable as RX_Next_Highest, the fourth variable as RX_Next, the fifth variable as RX_Highest_Status, and the seventh variable as RX_Next_Status_Trigger as an example:

RX_Next is the next SN of the last RLC SDU received in sequence completely;

RX_Next_Highest is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDU;

RX_Next_Status_Trigger is the next SN of the SN that triggers the start of the reassembly timer;

RX_Highest_Status is the highest SN among all SNs indicated to the upper layer as ACK_SN.

Step 704, (a certain) downlink AM RLC entity in the UE receives the first RLC PDU from the MAC layer, and the first RLC PDU corresponds to an RLC SDU segment;

If the downlink AM RLC entity receives an RLC PDU, and the RLC PDU corresponds to an RLC SDU, remove the RLC header of the RLC PDU to obtain the RLC SDU, and send the RLC SDU to the upper layer.

If the downlink AM RLC entity receives a UMD PDU from the MAC layer, and the UMD PDU corresponds to an RLC SDU segment, and the SN is greater than or equal to RX_Next_Reassembly, it puts the received UMD PDU into the receive buffer.

The SN is the sequence number of the RLC SDU, and different RLC SDUs have different SNs. When one RLC SDU is segmented into at least two RLC SDU segments, the at least two RLC SDU segments have the same SN. In addition, the at least two RLC SDU segments also have other information for identifying the segment order and segment start position, and the other information is used to reassemble the at least two RLC SDU segments into RLC SDUs.

The UE performs at least one of steps 705 to 708:

Step 705, in the case that neither the reorganization offset timer nor the reorganization timer is running, and any one of the following first start conditions is satisfied, start the reorganization offset timer;

The first start condition of the reassembly offset timer includes any one of the following two conditions:

Start condition 1: if RX_Next_Highest>RX_Next+1;

Start condition 2: If RX_Next_Highest=RX_Next+1, and for the first RLC SDU corresponding to SN=RX_Next, there is at least one unreceived bit segment before the last bit in the segment of the first RLC SDU that has been received ;

Among them, RX_Next_Highest is the next SN of the SN of the third RLC PDU with the largest SN in the received RLC PDUs, and RX_Next is the next SN of the last RLC SDU that is completely received in sequence.

Step 706, in the case that the reassembly offset timer times out, start the reassembly timer;

Step 707, when the reassembly timer times out and the following second activation condition is satisfied, start the reassembly offset timer, and set RX_Next_Status_Trigger to RX_Next_Highest;

When the reassembly timer expires, the downstream AM RLC entity performs the following operations:

1) Update RX_Highest_Status to be not less than RX_Next_Status_Trigger and have not received the SN corresponding to the first RLC SDU of all bytes;

2) If any one of the following second start conditions is met, start t-Reassembly offset, and set RX_Next_Status_Trigger to RX_Next_Highest at the same time.

Condition 1: if RX_Next_Highest>RX_Highest_Status+1;

Condition 2: If RX_Next_Highest=RX_Highest_Status+1 and for the fourth RLC SDU corresponding to SN=RX_Highest_Status, there is at least one unreceived bit segment before the last bit in the segment of the received fourth RLC SDU.

In step 708, when the reorganization offset timer is running, and any one of the following stop conditions is satisfied, stop and reset the reorganization offset timer; or, when the reorganization timer is running, the following stop conditions are satisfied: In the case of any of the conditions, the reassembly timer is stopped and reset.

If the reassembly timer t-Reassembly is running, or if the reassembly offset timer t-Reassembly offset is running, stop and reset the running t-Reassembly offset if any of the following 3 stop conditions are met (if t-Reassembly offset is running), stop and reset running t-Reassembly (if t-Reassembly is running).

Stop condition 1: if RX_Next_Status_Trigger=RX_Next;

Stop condition 2: If RX_Next_Status_Trigger=RX_Next+1, and for the first RLC SDU corresponding to SN=RX_Next, there is no unreceived bit segment before the last bit in the segment of the currently received first RLC SDU;

Stop Condition 3: RX_Next_Status_Trigger is outside the reassembly receive window and RX_Next_Status_Trigger is not equal to RX_Next+AM_Window_Size. AM_Window_Size is the downlink receive window length of the downlink AM RLC entity.

To sum up, in the method provided by this embodiment, the reorganization offset timer is added and set, so that the reorganization waiting time of the RLC entity becomes the sum of the reorganization offset timer and the reassembly timer, thereby avoiding the reorganization waiting time of the RLC entity. The duration is too short to normally trigger the RLC status report requesting RLC retransmission. This embodiment can provide backward compatibility of the technical solution under the condition that the original design structure of the reassembly timer remains unchanged as much as possible.

In the method provided by this embodiment, for the UM receiving mode, the start condition and stop condition of the reassembly offset timer are also set, so that the reassembly offset timer can be turned on or off reasonably, and the backward compatibility of the technical solution is improved. .

In a schematic example with reference to FIG. 8, it is assumed that the downlink AM RLC entity maintains the following three variables for the reassembly receiving window: the following four variables: RX_Next, RX_Next_Status_Trigger, RX_Highest_Status and RX_Next_Highest;

1. The network device sends AMD PDU1 to the UE, but the UE fails to receive AMD PDU1 (SN=X) successfully, and feeds back a negative feedback (NACK) to the network device.

2. The network device sends the AMD PDU2 to the UE, the UE successfully receives the AMD PDU2 (SN=X), and feeds back an acknowledgment feedback (ACK) to the network device. Since AMD PDU2 corresponds to segment 2 of RLC SDU n, SN=X of RLC SDU n. After successfully receiving AMDPDU2,

RX_Next_Highest=x+1, RX_Next_Status_Trigger=0, RX_Next=x.

Since RX_Next_Highest=RX_Next+1=x+1, and the segment 1 of the RLC SDUn with SN=x is not received, the UE starts the reassembly offset timer t-Reassembly offset, the reassembly offset timer t-Reassembly offset= 3 RTTs. At the same time, set RX_Next_Status_Trigger=RX_Next_Highest=x+1.

Then the state variable at this time is:

RX_Next_Highest=x+1, RX_Next_Status_Trigger=x+1, RX_Next=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, AMD PDU2 is buffered in the reassembly receive window for reassembly.

3. The network device sends the AMD PDU3 to the UE, and the UE successfully receives the AMD PDU3 and feeds back an acknowledgment feedback (ACK) to the network device. Since AMD PDU3 corresponds to RLC SDU n+1, RLC SDU n+1 is an unsplit RLC SDU and does not have an SN. Then the state variable at this time is:

RX_Next_Highest=x+1, RX_Next_Status_Trigger=x+1, RX_Next=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, the RLC entity of the UE reports the RLC SDUn+1 to the MAC layer entity.

4. The network device sends the AMD PDU4 to the UE, the UE successfully receives the AMD PDU4 (SN=X+1), and feeds back an acknowledgment feedback (ACK) to the network device. Since AMD PDU4 corresponds to segment 1 of RLC SDU n+2, the SN of RLC SDU n+2 is X+1. Then the state variable at this time is:

RX_Next_Highest=x+2, RX_Next_Status_Trigger=x+1, RX_Next=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, AMD PDU2 and AMD PDU 4 are buffered in the reassembly receive window for reassembly.

5. The network device sends the AMD PDU5 to the UE, the UE successfully receives the AMD PDU5 (SN=X+1), and feeds back an acknowledgment feedback (ACK) to the network device. Since AMD PDU5 corresponds to segment 1 of RLC SDU n+2, the SN of RLC SDU n+2 is X+1. Then the state variable at this time is:

RX_Next_Highest=x+2, RX_Next_Status_Trigger=x+1, RX_Next=x.

Since the reassembly offset timer t-Reassembly offset has already run, but none of the three stop conditions are satisfied, the reassembly offset timer t-Reassembly offset is kept running. At the same time, the two segments in AMD PDU4 and AMD PDU 5 are reorganized into RLC SDU n+2, and the RLC entity of the UE reports RLC SDUn+2 to the MAC layer entity. The AMD PDU2 buffer is waiting for reassembly in the reassembly receive window.

6. The network device sends the AMD PDU1 to the UE again, but the UE fails to receive the AMD PDU1 (SN=X), and feeds back a negative feedback (NACK) to the network device. Since AMD PDU1 corresponds to segment 1 of RLC SDU n, SN=X of RLC SDU n. Then the state variable at this time is:

RX_Next_Highest=x+2, RX_Next_Status_Trigger=x+1, RX_Next=x.

Since RX_Next_Highest>RX_Next+1, and the reassembly offset timer t-Reassembly offset is running, continue to keep t-Reassembly offset running.

7. The network device sends the AMD PDU1 to the UE again, but the UE fails to receive the AMD PDU1 (SN=X) successfully, and feeds back a negative feedback (NACK) to the network device. Since AMD PDU1 corresponds to segment 1 of RLC SDU n, SN=X of RLC SDU n. Then the state variable at this time is:

RX_Next_Highest=x+2, RX_Next_Status_Trigger=x+1, RX_Next=x.

Since RX_Next_Highest>RX_Next+1, and the timer duration of the reassembly offset timer t-Reassembly offset expires, the UE continues to start the reassembly timer t-Reassembly to run.

8. When the reassembly timer t-Reassembly expires, update RX_Highest_status to the SN of the first RLC SDU that is not less than RX_T Next_Status_Trigger and has not received all bits, and triggers a status report. Since none of the start conditions of the reassembly offset timer are satisfied, the t-Reassembly offset is no longer started.

The above embodiment can be expressed as the following description:

Behavior when an AMD PDU is in the receive buffer

When a UMD PDU with SN=x is in the receive buffer, the AM RLC entity shall:

if x>=RX_Next_Highest;

-Update RX_Next_Highest to x+1.

If all bit fields of the RLC SDU with SN=x have been received:

- Reassemble the RLC SDU from the AMD PDU with SN=x, remove the RLC header and deliver the reassembled RLC SDU to the upper layer;

- if x=RX_Highest_Status,

- Update RX_Highest_Status to the third SN, which is the next SN of the current RX_Highest_Status corresponding to the RLC SDU for which all bits are not received.

- if x=RX_Next:

-Update RX_Next to the fourth SN, which is the next SN of the current RX_Next corresponding to the RLC SDU for which all bits are not received.

If the reassembly timer is running, or if the reassembly offset timer is running then if any of the following 3 conditions are met, stop and reset the running reassembly offset timer (if the reassembly offset timer is running running), stop and reset the running reassembly timer (if the reassembly timer is running).

Condition 1: if RX_Next_Status_Trigger=RX_Next;

Condition 2: If RX_Next_Status_Trigger=RX_Next+1, and for the first RLC SDU corresponding to SN=RX_Next, there is no unreceived bit segment before the last bit in the segment of the currently received first RLC SDU;

Condition 3: RX_Next_Status_Trigger is outside the reassembly receive window and RX_Next_Status_Trigger is not equal to RX_Next+AM_Window_Size;

If the reassembly offset timer is not running, and the reassembly timer is not running (including the case where the reassembly offset timer or the reassembly timer is stopped for the above reasons), then if either of the following 2 conditions is met.

Condition 1: if RX_Next_Highest>RX_Next+1;

Condition 2: If RX_Next_Highest=RX_Next+1, and for the first RLC SDU corresponding to SN=RX_Next, there is at least one unreceived bit segment before the last bit in the segment of the first RLC SDU that has been received;

If the reassembly offset timer is configured, start the reassembly offset timer; otherwise, start the reassembly timer. Setting also sets RX_Next_Status_Trigger to RX_Next_Highest.

When the reassembly offset timer expires, the reassembly timer is started.

Behavior when the reassembly timer expires:

If the reassembly timer expires, the AM RLC entity performs the following actions:

Update RX_Highest_Status to the SN corresponding to the first RLC SDU not less than RX_Next_Status_Trigger and not yet received all bits;

If any of the following 2 conditions are met:

Condition 1: if RX_Next_Highest>RX_Highest_Status+1;

Condition 2: If RX_Next_Highest=RX_Highest_Status+1 and for the RLC SDU corresponding to SN=RX_Highest_Status, there is at least one unreceived bit segment before the last bit in the currently received segment of the RLC SDU.

Then if the reassembly offset timer is configured, the reassembly offset timer is started, and RX_Next_Status_Trigger is set to RX_Next_Highest at the same time.

FIG. 9 shows a block diagram of an apparatus for starting a reassembly timer provided by an exemplary embodiment of the present application. The apparatus can be implemented as a terminal or a part in the terminal, and the apparatus includes:

a receiving module 920, configured to receive the first RLC PDU from the MAC layer, the first RLC PDU corresponds to an RLC SDU segment;

A timer module 940, configured to start the reassembly offset timer when the first RLC PDU satisfies the first start condition of the reassembly offset timer and neither the reassembly offset timer nor the reassembly timer is started A reassembly offset timer; when the reassembly offset timer expires, the reassembly timer is started.

In a possible implementation of this embodiment, the first start condition includes any one of the following two conditions:

The second RLC SDU preceding the first RLC SDU has at least one bit that has not been received;

At least one bit belonging to the first RLC SDU corresponding to the first RLC PDU and located before the first RLC PDU has not been received.

In a possible implementation of this embodiment, the RLC entity includes a downlink unacknowledged mode radio link control UM RLC receiving entity, and the downlink UM RLC receiving entity maintains a first variable and a second variable for the reassembly receiving window;

The first start condition includes any one of the following two conditions:

if the first variable > the second variable + 1;

If the first variable = the second variable + 1, and for a first RLC SDU with sequence number SN equal to the second variable, there is at least one received before the last bit of the first RLC SDU unreceived bit segments;

Wherein, the first variable is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, and the second variable is the minimum SN in the reorganization receiving window.

In a possible implementation of this embodiment, the first variable is RX_Next_Highest, and the second variable is RX_Next_Reassembly.

In a possible implementation of this embodiment, the timer module 940 is further configured to start the reassembly offset timer again when the reassembly timer times out and the first activation condition is satisfied.

In a possible implementation of this embodiment, the timer module 940 is further configured to stop and reset the reassembly offset timer when the reassembly offset timer is running and a stop condition is satisfied .

In a possible implementation of this embodiment, the RLC entity includes a downlink unacknowledged mode radio link control UM RLC receiving entity, and the downlink UM RLC receiving entity maintains a first variable, a second variable and third variable;

The stop condition includes any one of the following three conditions:

if said third variable <= said second variable;

if the third variable falls outside the recombination acceptance window, and the third variable is not equal to the first variable;

The first variable=the second variable+1, and for the first RLC SDU corresponding to the sequence number SN=the second variable, the last bit of the first RLC SDU that has been received has not been unreceived before to the bit segment;

The first variable is the next SN of the SN corresponding to the second RLC PDU with the largest SN in the received RLC PDUs, and the third variable is the next SN of the SN that triggers the start of the reassembly offset timer SN, the second variable is the minimum SN within the reassembled receive window.

In a possible implementation of this embodiment, the first variable is RX_Next_Highest, the second variable is RX_Next_Reassembly, and the third variable is RX_Timer_Trigger.

In a possible implementation of this embodiment, the RLC entity includes a downlink acknowledgement mode radio link control AM RLC entity, and the downlink AM RLC entity maintains a first variable and a fourth variable for the reassembly receiving window;

The first start condition includes any one of the following two conditions;

if the first variable > the fourth variable+1;

If the first variable = the fourth variable + 1, and for sequence number SN = the first RLC SDU corresponding to the fourth variable, the last of the segments of the first RLC SDU that have been received There is at least one unreceived bit segment preceding the bit;

Wherein, the first variable is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, and the fourth variable is the next SN of the last RLC SDU received in sequence and completely.

In a possible implementation of this embodiment, the first variable is RX_Next_Highest, and the fourth variable is RX_Next.

In a possible implementation of this embodiment, the RLC entity includes a downlink acknowledgement mode radio link control AM RLC entity, and the downlink AM RLC entity maintains a first variable and a fifth variable for the reassembly receiving window;

The device also includes:

In the case that the reassembly timer times out and the second activation condition is satisfied, start the reassembly offset timer;

The second start condition includes any one of the following two conditions:

if the first variable > the fifth variable+1;

If the first variable = the fifth variable + 1, and for sequence number SN = the fourth RLC SDU corresponding to the fifth variable, the last of the segments of the fourth RLC SDU that have been received There is at least one unreceived bit segment preceding the bit;

Wherein, the first variable is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, and the fifth variable is the largest SN among all the SNs indicated to the upper layer as ACK_SN.

In a possible implementation of this embodiment, the first variable is RX_Next_Highest, and the fifth variable is RX_Highest_Status.

In a possible implementation of this embodiment, the timer module 940 is further configured to stop and reset the reassembly offset timer when the reassembly offset timer is running and a stop condition is satisfied .

In a possible implementation of this embodiment, the RLC entity includes a downlink acknowledgement mode radio link control AM RLC entity, and the downlink AM RLC entity maintains a fourth variable and a sixth variable for the reassembly receiving window; the stopping Conditions include any of the following three conditions:

if the sixth variable = the fourth variable;

If the sixth variable=the fourth variable+1, and for the first RLC SDU corresponding to the sequence number SN=the fourth variable, before the last bit in the segment of the received first RLC SDU no unreceived bit segments;

if the sixth variable is outside the recombination reception window, and the sixth variable is not equal to the fourth variable plus the seventh variable;

Wherein, the sixth variable is the next SN of the SN that triggers the start of the reassembly offset timer, the fourth variable is the next SN of the last RLC SDU received in sequence and completely, and the seventh variable is The downlink receiving window length of the downlink AM RLC entity.

In a possible implementation of this embodiment, the fourth variable is RX_Next, the sixth variable is RX_Next_Status_Trigger, and the seventh variable is AM_Window_Size.

In a possible implementation of this embodiment, the receiving module 920 is configured to receive configuration information, where the configuration information is used to configure the timer duration of the reassembly offset timer of the RLC entity.

In a possible implementation of this embodiment, the timer duration of the reassembly offset timer is greater than the round-trip transmission time RTT, where the RTT is the round-trip transmission time during data transmission between the terminal and the network device.

In a possible implementation of this embodiment, the timer duration of the reassembly offset timer is equal to the product of the round-trip transmission time RTT and the maximum number of retransmissions.

In a possible implementation of this embodiment, the configuration information is applicable to all radio bearers of the terminal; or, the configuration information is applicable to a specified radio bearer among all radio bearers of the terminal.

FIG. 10 shows a block diagram of a configuration apparatus provided by an exemplary embodiment of the present application. The apparatus can be implemented as a terminal or a part in the terminal, and the apparatus includes:

The sending module 1020 is configured to send configuration information to the terminal, where the configuration information is used to configure the timer duration of the reassembly offset timer of the RLC entity.

In a possible implementation of this embodiment, the timer duration of the reassembly offset timer is greater than the round-trip transmission time RTT, where the RTT is the round-trip transmission time during data transmission between the UE and the network device.

In a possible implementation of this embodiment, the timer duration of the reassembly offset timer is equal to the product of the round-trip transmission time RTT and the maximum number of retransmissions.

In a possible implementation of this embodiment, the configuration information is applicable to all radio bearers of the UE; or, the configuration information is applicable to a specified radio bearer among all radio bearers of the UE.

FIG. 11 shows a schematic structural diagram of a communication device (network device or terminal device) provided by an exemplary embodiment of the present application. The communication device includes a processor 101 , a receiver 102 , a transmitter 103 , a memory 104 and a bus 105 .

The processor 101 includes one or more processing cores, and the processor 101 executes various functional applications and information processing by running software programs and modules.

The receiver 102 and the transmitter 103 may be implemented as a communication component, which may be a communication chip.

The memory 104 is connected to the processor 101 through the bus 105 .

The memory 104 may be configured to store at least one instruction, and the processor 101 may be configured to execute the at least one instruction, so as to implement various steps in the foregoing method embodiments.

Additionally, memory 104 may be implemented by any type or combination of volatile or non-volatile storage devices including, but not limited to, magnetic or optical disks, electrically erasable programmable Read Only Memory (Erasable Programmable Read Only Memory, EEPROM), Erasable Programmable Read Only Memory (EPROM), Static Random Access Memory (SRAM), Read Only Memory (Read -Only Memory, ROM), magnetic memory, flash memory, programmable read-only memory (Programmable Read-Only Memory, PROM).

In an exemplary embodiment, a computer-readable storage medium is also provided, wherein the computer-readable storage medium stores at least one instruction, at least one piece of program, code set or instruction set, the at least one instruction, the At least one section of program, the code set or the instruction set is loaded and executed by the processor to implement the method for starting the reassembly timer provided by the above method embodiments and executed by the terminal device, or the configuration method executed by the network device.

Those of ordinary skill in the art can understand that all or part of the steps of implementing the above embodiments can be completed by hardware, or can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. The storage medium mentioned may be a read-only memory, a magnetic disk or an optical disk, etc.

The above descriptions are only optional embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection of the present application. within the range.

Claims (28)

1. A method for starting a reassembly timer, characterized in that it is used in a radio link control RLC entity, the method comprising:

   Receive a first radio link control protocol data unit RLC PDU from the medium access control MAC layer, where the first RLC PDU corresponds to a radio link control service data unit RLC SDU segment;

   When the first RLC PDU satisfies the first start condition of the reassembly offset timer, and neither the reassembly offset timer nor the reassembly timer is started, start the reassembly offset timer;

   When the reassembly offset timer expires, the reassembly timer is started.
2. The method according to claim 1, wherein the first start condition comprises any one of the following two conditions:

   The second RLC SDU preceding the first RLC SDU has at least one bit that has not been received;

   At least one bit belonging to the first RLC SDU corresponding to the first RLC PDU and located before the first RLC PDU has not been received.
3. The method according to claim 1 or 2, wherein the RLC entity comprises a downlink unacknowledged mode radio link control UM RLC receiving entity, and the downlink UM RLC receiving entity maintains the first variable and the second variable;

   The first start condition includes any one of the following two conditions:

   if the first variable > the second variable + 1;

   If the first variable = the second variable + 1, and for a first RLC SDU with sequence number SN equal to the second variable, there is at least one received before the last bit of the first RLC SDU unreceived bit segments;

   Wherein, the first variable is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, and the second variable is the minimum SN in the reorganization receiving window.
4. The method of claim 3, wherein the first variable is RX_Next_Highest and the second variable is RX_Next_Reassembly.
5. The method according to any one of claims 1 to 4, wherein the method further comprises:

   When the reassembly timer expires and the first activation condition is satisfied, the reassembly offset timer is started again.
6. The method according to any one of claims 1 to 5, wherein the method further comprises:

   In the case that the reassembly offset timer is running and the following stop conditions are satisfied, the reassembly offset timer is stopped and reset.
7. The method according to claim 6, wherein the RLC entity comprises a downlink unacknowledged mode radio link control UM RLC receiving entity, and the downlink UM RLC receiving entity maintains the first variable and the second variable for the reassembly receiving window. variable;

   The stop condition includes any one of the following three conditions:

   if said third variable <= said second variable;

   if the third variable falls outside the recombination acceptance window, and the third variable is not equal to the first variable;

   If the first variable = the second variable + 1, and for the first RLC SDU corresponding to the sequence number SN = the second variable, the received last bit of the first RLC SDU has no pending received bit segments;

   The first variable is the next SN of the SN corresponding to the second RLC PDU with the largest SN in the received RLC PDUs, and the third variable is the next SN of the SN that triggers the start of the reassembly offset timer SN, the second variable is the minimum SN within the reassembled receive window.
8. The method of claim 7, wherein the first variable is RX_Next_Highest, the second variable is RX_Next_Reassembly, and the third variable is RX_Timer_Trigger.
9. The method according to claim 1 or 2, wherein the RLC entity comprises a downlink acknowledgement mode radio link control AM RLC entity, and the downlink AM RLC entity maintains variables fourth variables _Highest and the fourth variable;

   The first start condition includes any one of the following two conditions;

   if the first variable > the fourth variable+1;

   If the first variable = the fourth variable + 1, and for sequence number SN = the first RLC SDU corresponding to the fourth variable, the last of the segments of the first RLC SDU that have been received There is at least one unreceived bit segment preceding the bit;

   Wherein, the first variable is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, and the fourth variable is the next SN of the last RLC SDU received in sequence and completely.
10. The method of claim 9, wherein the first variable is RX_Next_Highest and the fourth variable is RX_Next.
11. The method according to any one of claims 1, 7 to 10, wherein the RLC entity comprises a downlink acknowledgement mode radio link control AM RLC entity, and the downlink AM RLC entity maintains a first-order RLC entity for the reassembly receiving window. a variable and a fifth variable;

    The method also includes:

    When the reassembly timer times out and the following second activation condition is satisfied, start the reassembly offset timer;

    The second start condition includes any one of the following two conditions:

    if the first variable > the fifth variable+1;

    If the first variable = the fifth variable + 1, and for sequence number SN = the fourth RLC SDU corresponding to the fifth variable, the last of the segments of the fourth RLC SDU that have been received There is at least one unreceived bit segment preceding the bit;

    Wherein, the first variable is the next SN of the SN corresponding to the third RLC PDU with the largest SN in the received RLC PDUs, and the fifth variable is the largest SN among all the SNs indicated to the upper layer as ACK_SN.
12. The method of claim 11, wherein the first variable is RX_Next_Highest and the fifth variable is RX_Highest_Status.
13. The method according to any one of claims 1, 7 to 12, wherein the method further comprises:

    If the reassembly offset timer is running and the stop condition is satisfied, the reassembly offset timer is stopped and reset.
14. The method according to claim 9, wherein the RLC entity comprises a downlink acknowledgment mode radio link control AM RLC entity, and the downlink AM RLC entity maintains a fourth variable and a sixth variable for the reassembly receiving window; The above stop condition includes any one of the following three conditions:

    if the sixth variable = the fourth variable;

    If the sixth variable = the fourth variable plus 1, and for sequence number SN = the first RLC SDU corresponding to the fourth variable, before the last bit in the segment of the first RLC SDU that has been received no unreceived bit segments;

    if the sixth variable is outside the recombination reception window, and the sixth variable is not equal to the fourth variable plus the seventh variable;

    Wherein, the sixth variable is the next SN of the SN that triggers the start of the reassembly offset timer, the fourth variable is the next SN of the last RLC SDU received in sequence and completely, and the seventh variable is The downlink receiving window length of the downlink AM RLC entity.
15. The method of claim 14, wherein the sixth variable is RX_Next_Status_Trigger, the fourth variable is RX_Next, and the seventh variable is AM_Window_Size.
16. The method according to any one of claims 1 to 15, wherein the method further comprises:

    Receive configuration information, where the configuration information is used to configure the timer duration of the reassembly offset timer of the RLC entity.
17. The method according to claim 16, wherein the timer duration of the reassembly offset timer is greater than the round-trip transmission time RTT, and the RTT is the round-trip transmission time during data transmission between the terminal and the network device.
18. The method according to claim 16, wherein the timer duration of the reassembly offset timer is equal to the product of the round-trip transmission time RTT and the maximum number of retransmissions.
19. The method of claim 16, wherein:

    The configuration information is applicable to all radio bearers of the terminal;

    or,

    The configuration information is applicable to a specified radio bearer among all radio bearers of the terminal.
20. A configuration method, characterized in that the method comprises:

    The network device sends configuration information to the terminal, where the configuration information is used to configure the timer duration of the reassembly offset timer of the radio link control RLC entity.
21. The method according to claim 20, wherein the timer duration of the reassembly offset timer is greater than the round-trip transmission time RTT, and the RTT is the round-trip transmission time during data transmission between the terminal and the network device .
22. The method according to claim 20, wherein the timer duration of the reassembly offset timer is equal to the product of the round-trip transmission time RTT and the maximum number of retransmissions.
23. The method of claim 20, wherein:

    the configuration information is applicable to all radio bearers of the terminal;

    or,

    The configuration information is applicable to a specified radio bearer among all radio bearers of the terminal.
24. An RLC entity device, characterized in that the device comprises:

    a receiving module, configured to receive a first radio link control protocol data unit RLC PDU from the media access control MAC layer, where the first RLC PDU corresponds to a radio link control service data unit RLC SDU segment;

    A timer module, configured to start the reorganization when the first RLC PDU satisfies the first start condition of the reassembly offset timer, and neither the reassembly offset timer nor the reassembly timer is started an offset timer; when the reassembly offset timer expires, the reassembly timer is started.
25. A configuration device, characterized in that the device comprises:

    The sending module is configured to send configuration information to the terminal, where the configuration information is used to configure the timer duration of the reassembly offset timer of the radio link control RLC entity.
26. A terminal, characterized in that the terminal comprises:

    processor;

    a transceiver connected to the processor;

    memory for storing executable instructions for the processor;

    Wherein, the processor is configured to load and execute the executable instructions to implement the method for starting a reassembly timer according to any one of claims 1 to 19.
27. A network device, characterized in that the network device includes:

    processor;

    a transceiver connected to the processor;

    memory for storing executable instructions for the processor;

    Wherein, the processor is configured to load and execute the executable instructions to implement the configuration method as claimed in any one of claims 20 to 23.
28. A computer-readable storage medium, wherein executable instructions are stored in the readable storage medium, and the executable instructions are loaded and executed by the processor to implement any one of claims 1 to 19. The method for starting the reassembly timer described above, or the configuration method described in any one of claims 20 to 23.

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