WO2017071281A1

WO2017071281A1 - Method and device for adjusting duration of polling timer of radio link control layer

Info

Publication number: WO2017071281A1
Application number: PCT/CN2016/088220
Authority: WO
Inventors: 吕应权
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-10-29
Filing date: 2016-07-01
Publication date: 2017-05-04
Also published as: CN106658546A

Abstract

A method and device for adjusting a duration of a polling timer of a radio link control layer. The method comprises: in the current process of starting a poll retransmission timer for performing poll transmission, calculating a poll round trip time, wherein the poll round trip time is a time interval between a transmission time at which a poll data packet is transmitted and a receiving time at which a status report data packet corresponding to the poll data packet is received; and obtaining a timer duration by adding a predetermined time margin to the poll round trip time.

Description

Method and device for adjusting duration of radio link control layer polling timer

Technical field

This document relates to, but is not limited to, the field of communications, and in particular, to a method and apparatus for adjusting the duration of a radio link control (RLC) polling timer.

Background technique

The RLC layer in the Long Term Evolution (LTE) system is located between the Medium Access Control (MAC) layer of the protocol stack access layer and the Packet Data Convergence Protocol (PDCP) layer. It mainly performs the functions of the Protocol Data Unit (PDU), the Service Data Unit (SDU), and the retransmission of the PDU. It supports three data transmission modes: Transparent Mode (TM, Transparent Mode), Unacknowledged Mode (UM, Unacknowledged) and Acknowledge Mode (AM, Acknowledge Mode). In order to ensure the normal operation of the wireless link and the high speed of the link transmission, the RLC layer is an important part of the core channel of the LTE system. Three types of timers are defined, that is, the reordering timer (AM, UM receiving end entity can use It is used to check whether there is packet loss at the bottom.) The status prohibit timer (used by the AM RLC receiver entity to ensure that only one status report is sent in a period of time), and the polling retransmission timer (AM RLC sender entity is used to ensure Each time interval, a PDU with a polling bit must be sent, that is, the transmitting end triggers the receiving end to send a status report).

The appropriate configuration of the timer duration has a large impact on the performance improvement of the system. For example, if the polling retransmission timer is too large, if the packet is lost in the air interface, the RLC window cannot be moved quickly. Therefore, the rate will decrease. If the timer duration is too small, polling retransmission will be initiated frequently, resulting in unnecessary air interface resource consumption.

The RLC protocol 36.322 of the 3rd Generation Partnership Project (3GPP) indicates that these three timers are configured by Layer 3 Radio Resource Control (RRC). However, this fixed configuration is inaccurate. Especially when the quality of the air interface changes during the service maintenance process, the length of the fixed configuration timer cannot be changed and cannot be quickly adapted, thereby affecting the performance of the system.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

The embodiment of the present invention is to provide a method and a device for adjusting the duration of a radio link control layer polling timer, which can adaptively adjust the duration of the RLC polling timer to improve system performance.

The technical solution of the embodiment of the present invention is implemented as follows:

A method for adjusting a duration of a radio link control layer polling timer, the method comprising:

In the process of starting the polling retransmission timer for polling transmission, the calculation obtains a polling loopback time, where the polling loopback time is the sending time of sending the polling data packet and receiving the polling data packet. The time interval between the reception times of the corresponding status report packets;

And adding the polling loopback time to the preset time margin to obtain a timer duration;

The next time the polling retransmission timer is started, the duration of the next polling retransmission timer is adjusted to the obtained timer duration.

In the above solution, in the process of starting the polling retransmission timer to perform polling retransmission, the calculation obtains the polling loopback time, including:

When the current polling retransmission timer is started, and the polling data packet of the polling location 1 is sent, the sending time T1 of the polling data packet and the serial number SN are recorded;

When the sequence number LSN of the next packet to be received data carried in the received status report data packet is SN+1, the reception time T2 of receiving the status report data packet is recorded;

The calculation obtains the polling loopback time as T2-T1.

In the above solution, the adjusting the length of the next polling retransmission timer to the obtained timer duration T includes:

Adjusting the duration of the next polling retransmission timer to the obtained time when the obtained timer duration is within a preset polling retransmission timer duration theoretical range [T _min , T _max ] Timer duration.

In the above solution, the adjusting the duration of the next polling retransmission timer is the obtained The timer duration T also includes:

When the timer duration T is less than the T _min , adjusting the duration of the next polling retransmission timer is the T _min ;

When the timer duration T is greater than the T _max , the duration of the next polling retransmission timer is adjusted to be the T _max .

In the above solution, the method further includes:

When the LSN carried in the received status report packet is not SN+1, the recorded transmission time T1 and the sequence number SN are set to an invalid value.

A duration adjustment apparatus for a radio link control layer polling timer, the apparatus comprising:

The calculating unit is configured to calculate a polling loopback time during the polling transmission of the current polling retransmission timer, and add the polling loopback time to the preset time margin to obtain the timer duration. The polling loopback time is a time interval between a sending time of sending a polling data packet and a receiving time of a status report data packet corresponding to receiving the polling data packet;

The adjusting unit is configured to adjust the duration of the next polling retransmission timer to be the timer duration calculated by the calculating unit when the polling retransmission timer is started next time.

In the above solution, the calculating unit includes: a recording subunit and a computing subunit;

The recording subunit is configured to record the transmission time T1 and the serial number SN of the polling data packet when the current polling retransmission timer is started, and the polling data packet of the polling position 1 is sent; When the sequence number LSN of the next packet to be received data carried in the status report data packet is SN+1, the reception time T2 of receiving the status report data packet is recorded;

The calculating subunit is configured to calculate and obtain a polling loopback time of T2-T1 according to the sending time T1 and the receiving time T2 recorded by the recording subunit.

In the above solution, the adjusting unit is configured to adjust the wheel when the timer duration calculated by the calculating unit is within a preset polling retransmission timer duration range [T _min , T _max ] The duration of the retransmission timer is the duration of the timer calculated by the computing unit.

In the above solution, the adjusting unit is further configured to adjust the duration of the polling retransmission timer to the _Tmin when the timer duration T calculated by the calculating unit is less than the _Tmin ; When the timer duration T calculated by the calculating unit is greater than the T _max , the duration of adjusting the polling retransmission timer is the T _max .

In the above solution, the calculating unit further includes: an invalid subunit,

The invalid subunit is configured to set the transmission time T1 and the sequence number SN recorded by the recording subunit to an invalid value when the LSN carried in the received status report data packet is not SN+1.

The embodiment of the invention provides a method and a device for adjusting the duration of a radio link control layer polling timer. In the process of starting the polling retransmission timer for polling transmission, the polling loopback time is calculated and obtained. The polling loopback time is added to the preset time margin to obtain the timer duration; when the polling retransmission timer is started next time, the duration of the polling retransmission timer is adjusted to be the timer duration. In this way, according to the polling loopback time of the current polling transmission, the duration of the polling retransmission timer used next time is adjusted, and the duration of the polling retransmission timer can be adaptively adjusted according to the change of the transmission environment, thereby improving the system. performance. In addition, from the evolution of the wireless communication network architecture, the deployment of functional entities after 5G is more flexible, and the control plane and user plane will be as independent as possible. By reducing the configuration of these parameters, the mutual coupling degree can be reduced, thereby reducing the complexity of the system. Sex.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic flowchart of a method for adjusting a duration of a radio link control layer polling timer according to Embodiment 1 of the present invention;

2 is a structural block diagram of a duration adjustment apparatus for a radio link control layer polling timer according to Embodiment 2 of the present invention;

FIG. 3 is a structural block diagram of another duration adjustment apparatus for a radio link control layer polling timer according to Embodiment 2 of the present invention.

Embodiments of the invention

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings.

Example 1

The embodiment provides a method for adjusting the duration of the radio link control layer polling timer. As shown in FIG. 1 , the processing procedure of the method in this embodiment includes the following steps:

Step 101: In the process of starting the polling retransmission timer for polling retransmission, the calculation obtains the polling loopback time.

For the polling retransmission timer, if the polling retransmission timer is too long, when there is a packet loss in the air interface, the RLC window cannot be moved quickly, and the rate will decrease if the timer duration is too small. Then, the polling retransmission is frequently initiated, resulting in unnecessary air interface resource consumption. The optimal duration for polling the retransmission timer should be slightly larger than the RTR (Round Trip Time) of the RLC layer data. In this way, the downlink data can be retransmitted because the acknowledgment of the RLC is not received, instead of confirming that the data is still retransmitted on the road; therefore, the method of the embodiment first calculates the polling loopback time.

The calculation process of the polling loopback time includes the following steps:

A1. When the polling retransmission timer is started and the polling packet of the polling location 1 is sent, the sending time T1 and the sequence number SN of the polling packet are recorded.

When the AM RLC entity initiates the polling retransmission, the polling data packet is first assembled, and then the current polling retransmission timer is started, and the polling data packet is sent. If the polling position in the polling data packet is 1, Indicates that the polling data packet can trigger the peer return status report data packet of the AM RLC entity, so the AM RLC entity records the sending time of the polling data packet when sending the polling data packet of the polling location 1 T1 and serial number (SN, Sequence Number), the serial number can be recorded as SN.

A2. When the LSN carried in the received status report data packet is SN+1, the receiving time of receiving the status report data packet is recorded.

After the peer end of the AM RLC entity receives the polling data packet, when the polling bit of the polling data packet is read as 1, the opposite end of the AM RLC entity returns a status to the AM RLC entity. The data packet is reported, and the status report data packet carries an LSN (Last Sequence Number of the next packet to be received data), and the LSN is SN+1.

Therefore, if the AM RLC entity receives a status report data packet, and the LSN carried in the status report data packet is SN+1, it indicates that the status report data packet is a polling data packet whose sequence number is SN. In response, the status report packet indicates that the opposite end of the AM RLC entity is received A polling packet with serial number SN. At this time, the AM RLC entity records the reception time T2 at which it receives the status report data packet.

Of course, when the LSN carried in the received status report packet is not SN+1, there are two possibilities. One possibility is that the peer end of the AM RLC entity does not receive data normally, such as packet loss, and One possibility is that the AM RLC entity sends a data packet whose polling bit is 1 after sending a data packet with a polling bit of 1, so that the opposite receiving end of the AM RLC entity may return LSN>SN+. 1 data. In both cases, the polling loopback time for the polling packet with sequence number SN cannot be calculated. The polling loopback time calculation fails, and the recorded sending time T1 and sequence number SN are set to Invalid value. Steps A1-A2 are repeated until T1 and T2 are obtained.

A3. The calculation obtains the polling loopback time as T2-T1.

The polling loopback time is a time interval between a sending time of sending a polling data packet and a receiving time of a status report data packet corresponding to receiving the polling data packet; therefore, the polling loopback time is T2 -T1.

Step 102: Add the polling loopback time plus a preset time margin to obtain a timer duration.

The optimal duration for polling the retransmission timer should be slightly larger than the polling loopback time, so the polling loopback time plus the preset time margin is used to obtain the timer duration. The preset time margin may be about 5 ms.

Step 103: Adjust the duration of the polling retransmission timer to be the duration of the timer when the polling retransmission timer is started next time.

Step 102: The time length of the obtained timer is slightly larger than the polling loopback time of the current polling retransmission. This duration ensures that in the current transmission environment, the AM RLC entity has sufficient time to receive the polling data during normal transmission. The status report packet corresponding to the package. The timer duration can be determined with greater probability because the downlink polling packet is retransmitted because the corresponding status report packet is not received, instead of the corresponding status report packet being polled on the way. Retransmission of the packet. Therefore, when the polling retransmission timer is started next time, the duration of the polling retransmission timer can be adjusted to be the duration of the timer.

The method in this embodiment adjusts the duration of the polling retransmission timer used next time according to the polling loopback time of the current polling transmission, and can adaptively adjust the polling retransmission timer according to the change of the transmission environment. The length of time increases the performance of the system.

In this embodiment, in order to ensure that the adjustment of the polling retransmission timer duration is within a safe range, the theoretical range [T _min , T _max ] of the polling retransmission timer duration may be preset, wherein the theoretical range [ T _min , T _max ] is set according to the capabilities of the system. For example, in the current LTE system, T _{min is at} least 2 ms, and T _max may be up to 60 ms.

The adjusting the duration of the polling retransmission timer is the timer duration T, including:

When the timer duration T is within the preset polling retransmission timer duration theoretical range [T _min , T _max ], the duration of the polling retransmission timer is adjusted to be the timer duration T.

In order to ensure that the adjusted polling retransmission timer duration is within a preset theoretical range, after the calculation obtains the timer duration T, the method further includes:

When the timer T is smaller than the length of T _min, adjusting the length of the polling for the retransmission timer T _min; When the timer T is larger than the length of T _max, to adjust the polling The duration of the retransmission timer is the T _max .

Example 2

The embodiment of the present invention further provides a duration adjustment device for a radio link control layer polling timer. As shown in FIG. 2, the device includes: a calculating unit 201 and an adjusting unit 202, where

The calculating unit 201 is configured to calculate a polling loopback time in the process of starting the polling retransmission timer for polling transmission, and add the polling loopback time to the preset time margin to obtain a timer. The polling loopback time is a time interval between a sending time of sending a polling data packet and a receiving time of a status report data packet corresponding to receiving the polling data packet;

The adjusting unit 202 is configured to adjust the duration of the polling retransmission timer to the timer duration calculated by the calculating unit 201 when the polling retransmission timer is started next time.

Optionally, as shown in FIG. 3, the calculating unit 201 includes: a recording subunit 2011 and a computing subunit 2012; wherein

The recording subunit 2011 is configured to record the transmission time T1 and the serial number SN of the polling data packet when the current polling retransmission timer is started, and the polling data packet of the polling position 1 is sent; When the LSN carried in the status report packet is SN+1, the receiving time T2 of receiving the status report data packet is recorded;

The calculation subunit 2012 is configured to calculate and obtain a polling loopback time of T2-T1 according to the transmission time T1 and the reception time T2 recorded by the recording subunit 2011.

Optionally, the adjusting unit 202 is configured to adjust the polling retransmission timing when the timer duration is within a preset polling retransmission timer duration range [T _min , T _max ] The duration of the timer is the duration of the timer.

The adjusting unit 202 is further configured to: when the timer duration T is less than the T _min , adjust a duration of the polling retransmission timer to be T _min ; and the timer duration T is greater than the When T _max , the duration of the polling retransmission timer is adjusted to be T _max .

As shown in FIG. 3, the calculating unit further includes: an invalid subunit 2013, wherein the invalid subunit 2013 is configured to set, when the LSN carried in the received status report data packet is not SN+1, The transmission time T1 and the sequence number SN recorded by the recording subunit 2011 are set to invalid values.

In practical applications, the computing unit 201 and the adjusting unit 202 described in this embodiment may be implemented by a central processing unit (CPU), a microprocessor (MPU), a digital signal processor (DSP) or a field on an AM RLC entity. Device gate array (FPGA), modem and other device implementations.

The embodiment of the invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the above method.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention can take the form of a hardware embodiment, a software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowcharts and/or block diagrams, and flow and/or A combination of boxes. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Industrial applicability

The foregoing technical solution can adaptively adjust the duration of the polling retransmission timer according to the change of the transmission environment, thereby improving the performance of the system; reducing the parameter configuration of the radio link control layer, and correspondingly reducing the coupling degree between the control plane and the user plane , thereby reducing the complexity of the system.

Claims

A method for adjusting a duration of a radio link control layer polling timer, the method comprising:

In the process of starting the polling retransmission timer for polling transmission, the calculation obtains a polling loopback time, where the polling loopback time is the sending time of sending the polling data packet and receiving the polling data packet. The time interval between the reception times of the corresponding status report packets;

And adding the polling loopback time to the preset time margin to obtain a timer duration;

The next time the polling retransmission timer is started, the duration of the next polling retransmission timer is adjusted to the obtained timer duration.
The method according to claim 1, wherein in the process of initiating the current polling retransmission timer for polling retransmission, the calculation obtains a polling loopback time, including:

When the current polling retransmission timer is started, and the polling data packet of the polling location 1 is sent, the sending time T1 of the polling data packet and the serial number SN are recorded;

When the sequence number LSN of the next packet to be received data carried in the received status report data packet is SN+1, the reception time T2 of receiving the status report data packet is recorded;

The calculation obtains the polling loopback time as T2-T1.
The method according to claim 1, wherein the adjusting the duration of the next polling retransmission timer to the obtained timer duration T comprises:

Adjusting the duration of the next polling retransmission timer to the obtained time when the obtained timer duration is within a preset polling retransmission timer duration theoretical range [T min , T max ] Timer duration.
The method according to claim 3, wherein the adjusting the duration of the next polling retransmission timer to the obtained timer duration T further includes:

When the timer duration T is less than the T min , adjusting the duration of the next polling retransmission timer is the T min ;

When the timer duration T is greater than the T max , the duration of the next polling retransmission timer is adjusted to be the T max .
The method of claim 2, the method further comprising:

When the LSN carried in the received status report packet is not SN+1, the recorded transmission time T1 and the sequence number SN are set to an invalid value.
A duration adjustment apparatus for a radio link control layer polling timer, the apparatus comprising:

The calculating unit is configured to calculate a polling loopback time during the polling transmission of the current polling retransmission timer, and add the polling loopback time to the preset time margin to obtain the timer duration. The polling loopback time is a time interval between a sending time of sending a polling data packet and a receiving time of a status report data packet corresponding to receiving the polling data packet;

The adjusting unit is configured to adjust the duration of the next polling retransmission timer to be the timer duration calculated by the calculating unit when the polling retransmission timer is started next time.
The apparatus according to claim 6, wherein said calculation unit comprises: a recording subunit and a calculation subunit;

The recording subunit is configured to record the transmission time T1 and the serial number SN of the polling data packet when the current polling retransmission timer is started, and the polling data packet of the polling position 1 is sent; When the sequence number LSN of the next packet to be received data carried in the status report data packet is SN+1, the reception time T2 of receiving the status report data packet is recorded;

The calculating subunit is configured to calculate and obtain a polling loopback time of T2-T1 according to the sending time T1 and the receiving time T2 recorded by the recording subunit.
The apparatus according to claim 6, wherein

The adjusting unit is configured to adjust the polling retransmission timing when the timer duration calculated by the calculating unit is within a preset polling retransmission timer duration range [T min , T max ] The duration of the timer is the timer duration calculated by the computing unit.
The device of claim 8

The adjusting unit is further configured to: when the timer duration T calculated by the calculating unit is less than the T min , adjust a duration of the polling retransmission timer to the T min ; calculate in the calculating unit When the timer duration T is greater than the T max , the duration of adjusting the polling retransmission timer is the T max .
The apparatus according to claim 7, wherein said calculating unit further comprises: an invalid subunit,

The invalid subunit is set to not carry the LSN carried in the received status report data packet. When SN+1, the transmission time T1 and the sequence number SN recorded by the recording subunit are set to invalid values.