CN115379586A

CN115379586A - Random access backoff optimization method and device

Info

Publication number: CN115379586A
Application number: CN202211008372.XA
Authority: CN
Inventors: 王飞; 翁金成; 付志亮
Original assignee: Shanghai Eigencomm Communication Technology Co ltd
Current assignee: Shanghai Eigencomm Communication Technology Co ltd
Priority date: 2022-08-22
Filing date: 2022-08-22
Publication date: 2022-11-22

Abstract

The invention provides a random access backspacing optimization method, which comprises the following steps: when detecting that the random access fails, acquiring a random access trigger reason, an RAR Backoff value and a timer running state of a current RRC layer; determining a target Backoff duration based on the random access trigger reason, the RAR Backoff value and the timer running state of the current RRC layer; and initiating random access again in different modes according to the target Backoff duration. When the UE detects that the random access fails, a proper Backoff mechanism is comprehensively formulated by combining the service requirement of an application layer and the signaling flow of the current RRC layer, so that the random access success rate is improved, and the power consumption of the UE is effectively reduced.

Description

Random access backoff optimization method and device

Technical Field

The present invention relates to the field of network technologies, and in particular, to a backoff optimization method and apparatus for random access.

Background

The random access is a process of establishing an initial Radio link between the UE and the Cell, and is mainly aimed at enabling the UE to obtain uplink time synchronization and a unique user identity C-RNTI (Cell Radio Network Temporary Identifier). The types of random access are further classified into contention-based and non-contention-based random access.

For 4/5G, the random access process is substantially similar for low-power Internet of things (Cat 1, eMTC/NB-IOT). The following description is given by taking a 4G LTE network as an example, and mainly includes the following steps: 1) UE sends a Random Access preamble (preamble) on PRACH (Physical Random Access Channel) resources, i.e. MSG1; 2) The UE monitors a PDCCH (Physical Downlink Control Channel) in an RAR (Random Access response) time window to receive an RAR, i.e. MSG2; 3) The UE sends MSG3 on PUSCH (Physical Uplink Shared Channel) and starts a contention resolution timer; 4) Before the contention resolution timer expires, the UE may monitor the PDCCH to receive a contention resolution message, i.e., MSG4. It is noted that the above steps 3) and 4) are not required for non-contention based random access.

Based on the above procedure, if the UE receives a BI (Backoff Indicator) in the RAR, a Backoff value specified by the BI is saved. It specifies the backoff time (random value within 0 to BI) before the UE retransmits the preamble. If the UE does not receive the RAR within the RAR time window, or none of the received raris (Random Access Preamble IDentifier) matches the Preamble in MSG1, it is determined that the RAR reception is failed. At this time, the UE needs to back off for a period of time and then starts random access. In addition, the same is true when MSG4 conflict resolution fails.

It follows that if the BI of the network configuration is large, access delay increases and power consumption increases. And the random access procedure may also be accompanied with RRC establishment/reestablishment/handover/recovery, etc., so the RRC layer needs to control the total access latency according to the duration of T300/T301/T304/T319. If the Backoff value is longer than the timers in the RRC layer, the probability of access failure increases. Especially for an NB-IOT (NB-IOT) terminal with high requirement on low power consumption, a better solution is needed for the increase of the power consumption.

In the prior art, a comprehensive and systematic Backoff mechanism starts from a service scene and is combined with power consumption. For example, for an NB-IOT terminal with a high requirement on low power consumption, especially for an intelligent meter reading service, the sending of small packet data is often time-efficient, and the sending opportunity may be missed by waiting for Backoff all the time. In addition, a certain random access failure does not mean that the packet data is not sent, but rather, the sending is cancelled in time, and the PSM is rapidly entered to save power consumption. For another example, for a reliably transmitted service, when a current cell is congested, access is still initiated in the current cell, and the network may also configure a BI, which may cause an access delay to be too large, and may also cause the access to fail due to timeout of an RRC layer timer. At this time, if the RRC is allowed to change to reside in a different cell, the access can be initiated quickly and the data transmission can be completed. Patents CN111757531a and CN114245477a do not combine with an actual service scenario, and are optimized in terms of improving a random access success rate alone, and influence caused by power consumption is not considered, and especially, the internet of things terminal with a high requirement on low power consumption is not optimized.

Disclosure of Invention

The invention aims to solve the technical problems that: when the UE detects that the random access fails, an appropriate Backoff mechanism needs to be comprehensively formulated by combining the service requirement of an application layer and the signaling flow of the current RRC layer, so that the power consumption of the UE is effectively reduced while the success rate of the random access is improved. The invention is realized by the following technologies:

in one aspect, the present invention provides a backoff optimization method for random access, including:

when detecting that the random access fails, acquiring a random access trigger reason, an RAR Backoff value and a timer running state of a current RRC layer;

determining a target Backoff duration based on the random access trigger reason, the RAR Backoff value and the timer running state of the current RRC layer;

and initiating random access again in different modes according to the target Backoff duration.

In some embodiments, the obtaining a random access trigger reason, a RAR Backoff value, and an operation state of a timer of a current RRC layer when a random access failure is detected includes:

if the random access is not triggered by the application layer data and a timer T300/T301/T304/T319 of an RRC layer is not operated, the target Backoff duration randomly takes values from 0 to an RAR Backoff value;

otherwise, randomly taking a value from 0 to min (RAR Backoff value, data residual effective duration and RRC timer residual running duration);

or the target Backoff time length is randomly selected from 0 to RAR Backoff value.

In some embodiments, the re-initiating random access in different manners according to the target Backoff duration includes:

and after waiting for the target Backoff duration, the MAC layer initiates random access on the original cell again.

if the random access is triggered by the application layer data, canceling the data transmission when the residual effective duration of the application layer data is less than or equal to the target Backoff duration, otherwise not canceling the data transmission; (ii) a

If the transmission is cancelled, the RRC/MAC is informed to execute the MAC RESET process;

if the data transmission is not canceled, determining whether to search for an available adjacent cell by combining the running state of a T300/T301/T304/T319 timer of the RRC layer;

if searching the available adjacent area, immediately initiating random access on the available adjacent area;

and if the available adjacent cell is not searched, initiating the random access again after the original cell waits for the target Backoff duration.

In some embodiments, the determining, if the data transmission is not cancelled, whether to search for an available neighboring cell in combination with the running state of the T300/T301/T304/T319 timer of the RRC layer includes:

if the cell is in the RRC establishment process and the residual time length of the T300 is less than or equal to the target Backoff time length, ending the RRC establishment process and searching the available adjacent cell;

if the cell is in the RRC reestablishment process and the residual time length of the T301 is less than or equal to the target Backoff time length, ending the RRC reestablishment process and searching the available adjacent cell;

if the cell is in the RRC switching process and the residual time length of the T304 is less than or equal to the target Backoff time length, ending the RRC switching process and searching the available adjacent cell;

if the cell is in the RRC recovery flow and the residual time length of the T319 is less than or equal to the target Backoff time length, ending the RRC recovery flow and searching the available adjacent cell;

otherwise, the available neighbor cell is not searched.

A backoff optimization apparatus for random access, comprising:

the acquisition module is used for acquiring a random access trigger reason, an RAR Backoff value and a timer running state of a current RRC layer when detecting the random access failure;

a determining module, configured to determine a target Backoff duration based on the random access trigger cause, the RAR Backoff value, and an operating state of the timer in the current RRC layer;

and the initiating module is used for initiating the random access again in different modes according to the target Backoff duration.

In some embodiments, the determining module is further configured to:

or the target Backoff time length is randomly selected from 0 to the RAR Backoff value.

In some embodiments, the initiating module is to:

if the available adjacent area is searched, random access is immediately initiated on the available adjacent area;

In some embodiments, a search module is included to:

if the cell is in the RRC establishing process and the residual time length of the T300 is less than or equal to the target Backoff time length, ending the RRC establishing process and searching the available adjacent cell;

and if the cell is in the RRC recovery flow and the residual time length of the T319 is less than or equal to the target Backoff time length, ending the RRC recovery flow and searching the available adjacent cell.

The random access backoff optimization method and system provided by the invention at least have the following beneficial effects: when the UE detects that the random access fails, a proper Backoff mechanism is comprehensively formulated by combining the service requirement of an application layer and the signaling flow of the current RRC layer, so that the power consumption of the UE is effectively reduced while the success rate of the random access is improved.

Drawings

The above features, technical features, advantages and implementations of a random access backoff optimization system will be further described in the following detailed description of preferred embodiments in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of an embodiment of a backoff optimization method for random access in the present invention;

fig. 2 is a schematic diagram of a Backoff mechanism in a random access failure in the present invention;

fig. 3 is a schematic diagram of a Backoff mechanism in a random access failure according to the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "a" means not only "only one of this but also a case of" more than one ".

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

In addition, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not intended to indicate or imply relative importance.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

In one embodiment, as shown in fig. 1, the present invention provides a backoff optimization method for random access, including:

s101, when detecting that the random access fails, obtaining a random access trigger reason, an RAR Backoff value and a timer running state of a current RRC layer.

S102, determining a target Backoff duration based on the random access trigger reason, the RAR Backoff value and the running state of the timer of the current RRC layer.

And S103, initiating random access again in different modes according to the target Backoff duration.

In this embodiment, when the UE detects a random access failure, a proper Backoff mechanism is synthetically formulated in combination with a service requirement of an application layer and a signaling flow of a current RRC layer, so that the power consumption of the UE is effectively reduced while the random access success rate is improved.

In an embodiment, the present invention provides a Backoff optimization method for random access, where the method, when detecting a random access failure, obtains a random access trigger cause, a RAR Backoff value, and a timer operating state of a current RRC layer, and determines a target Backoff duration, includes:

Exemplarily, when it is determined that the random access is not triggered by the application layer data and the timer of the RRC layer is not running, the target Backoff duration is randomly valued between 0 and the RAR Backoff value; otherwise, the target Backoff duration is randomly selected from 0 to min (RAR Backoff value, data remaining effective duration, and RRC timer remaining operation duration).

In this embodiment, if the current random access is not triggered by the application layer data and the T300/T301/T304/T319 timers of the RRC layer are not running, the T _ Target _ BI _ Delay value is randomly selected from 0 to T _ RAR _ BI _ Delay. Otherwise, values will be randomly taken from 0 to min (T _ RAR _ BI _ Delay, T _ Data _ Left _ BI _ Delay, T _ RRC _ Left _ BI _ Delay). Finally, the MAC will initiate random access again after waiting for the timeout of T _ Target _ BI _ Delay.

Specifically, as shown in fig. 2, the first scheme:

and 1. The UE detects the random access failure and determines that the network configures BI in the RAR and is not 0. If so, the RAR Backoff value (T _ RAR _ BI _ Delay) is specified by BI, otherwise set to 0. And if the T _ RAR _ BI _ Delay is not 0, jumping to the step 2, otherwise, setting the T _ Target _ BI _ Delay to be 0, and jumping to the step 5.

2. And determining whether the current random access is triggered by the application layer Data, if so, taking the Data residual effective duration of the application layer as a Data Backoff value (T _ Data _ Left _ BI _ Delay).

The application layer can indicate the validity period of the data packet in a signal for sending data, and the data packet is transmitted layer by layer and finally sent to the MAC layer.

3. And determining whether corresponding T300/T301/T304/T319 timers are running or not according to the current RRC layer signaling flow, and if so, taking the remaining time length of the timers as an RRC Backoff value (T _ RRC _ Left _ BI _ Delay).

Specifically, according to the RRC internal state, it may be determined that there are currently a connection establishment procedure (T300)/a reestablishment procedure (T301)/a handover procedure (T304)/a connection recovery (T319), and these procedures necessarily have corresponding timers running. In addition, the UE's own OS timer mechanism also knows whether these timers are running or not, and the remaining duration.

The remaining duration is the time interval from the current moment to the overtime moment of the timer.

T300: a timer for RRC connection establishment. And starting to time from the UE sending the MSG1, ending when RRCConnectionSetup or RRCConnectionReject is received, and recording as T300 time-out if the RRCConnectionSetup or RRCConnectionReject is not received within the period defined by the timer.

T301: a timer for RRC reestablishment.

The time counting is started when the UE sends the MSG1, the time counting is ended when the RRCConnectionReestablistigment or RRCConnectionReestablistigment Reject is received, and if the time counting is not received in the period defined by the timer, the time counting is recorded as T301 time-out.

T304: and switching the timer.

From the time when the UE receives RRCConnectionReconfiguration (including MobilityControlINfo), the time when the UE completes handover transmission RRCConnectionReconfiguration complete ends, and if the RRCConnectionReconfiguration complete is not received within the period defined by the timer, the time is recorded as T304 timeout.

T319: resume connection timer (38.331).

T319 is started when RRCRESUMeRequest/RRCRESUMeRequest1 is sent.

Stop running T319 if the following information is received:

RRCResumum/RRCSetup/RRCRelease/RRCRelease with suspend/RRCReject. If the message is not received, wait T319 times out.

4. Taking a minimum value among the T _ RAR _ BI _ Delay, the T _ Data _ Left _ BI _ Delay (if existing) and the T _ RRC _ Left _ BI _ Delay (if existing), and randomly taking a value between 0 and the minimum value as a Target Backoff duration (T _ Target _ BI _ Delay).

And 5, after waiting for the time-out of the T _ Target _ BI _ Delay, the MAC layer initiates the random access again.

The logic for determining the target Backoff duration includes two schemes:

the first scheme is as follows:

otherwise, the target Backoff duration is randomly selected from 0 to min (RAR Backoff value, data remaining effective duration, and RRC timer remaining operation duration).

Scheme II:

the target Backoff time length is randomly selected from 0 to RAR Backoff value.

In an embodiment, the present invention provides a Backoff optimization method for random access, where the method for re-initiating random access in different manners according to the target Backoff duration includes:

and if the available adjacent cell is not searched, after the original cell waits for the target Backoff duration, initiating the random access again.

When the residual effective duration of the application layer data is greater than the target Backoff duration, informing the RRC to determine whether to search an available adjacent cell according to the target Backoff duration;

and initiating random access on the available adjacent cell after searching the available adjacent cell. In an embodiment, the determining whether to search for an available neighboring cell in combination with the running state of the T300/T301/T304/T319 timer of the RRC layer if data transmission is not cancelled includes:

otherwise, the available neighbor cell is not searched.

In this embodiment, fig. 3 is a schematic diagram of a Backoff mechanism when a random access fails. The MAC determines the time length of the T _ Target _ BI _ Delay, the application layer determines whether to cancel data transmission (if the data transmission is random access triggered by application layer data) according to the T _ Target _ BI _ Delay, and finally the RRC determines whether to search for an available adjacent cell according to the T _ Target _ BI _ Delay and by combining a self service flow, and immediately initiates random access on the adjacent cell.

Specifically, as shown in fig. 3, the second scheme:

and 1. The UE detects the random access failure and determines that the network configures BI in the RAR and is not 0. If so, then T _ Target _ BI _ Delay is randomized between 0 and the BI assigned value, otherwise set to 0. If the T _ Target _ BI _ Delay is not 0, notifying the application layer (if the random access is triggered by the application layer data) and the RRC layer, and jumping to the step 2, otherwise, setting the T _ Target _ BI _ Delay to be 0 and jumping to the step 9;

2. if the residual effective duration of the application layer data is less than or equal to T _ Target _ BI _ Delay, the data transmission is cancelled, and the RRC/MAC is informed to execute the MAC RESET process so as to achieve the purpose of saving electricity;

3. if the residual effective duration of the application layer data is greater than T _ Target _ BI _ Delay, informing the RRC to continue initiating access;

the RRC is further optimized in consideration of the following steps according to the T _ Target _ BI _ Delay and the current signaling flow;

5. if the current RRC establishing process is in the RRC establishing process and the residual time length of the T300 is less than or equal to T _ Target _ BI _ Delay, the establishing process is ended in advance, the available adjacent cells are searched immediately, and then the establishing process is executed;

6. if the current RRC reconstruction process is in the RRC reconstruction process and the residual time length of the T301 is less than or equal to T _ Target _ BI _ Delay, the reconstruction process is ended in advance, an available adjacent cell is searched immediately, and then the establishment process is executed;

7. if the current RRC switching process is in the RRC switching process and the residual time length of the T304 is less than or equal to the T _ Target _ BI _ Delay, the switching process is ended in advance, the available adjacent cells are searched immediately, and then the reconstruction process is executed;

8. in addition, for 5G communication, the RRC recovery procedure needs to be considered. If the current RRC recovery flow is in the RRC recovery flow and the residual time length of the T319 is less than or equal to T _ Target _ BI _ Delay, the recovery flow is ended in advance, the available adjacent cells are searched immediately, and then the establishment flow is executed;

and 9, the RRC does not carry out any treatment, the original cell is kept to reside, and the MAC initiates random access again after waiting for the time-out of the T _ Target _ BI _ Delay.

The common point of both scheme 1 and scheme 2 is to shorten the time for waiting for BackOff as much as possible, and initiate random access or transmit data as early as possible, thereby reducing power consumption.

The difference between scheme 1 and scheme 2 is that scheme 1 shortens the BackOff time and initiates random access again on the current cell, while scheme 2 considers that the current flow is ended in advance and random access is initiated immediately on an available neighboring cell.

The invention also provides a random access backoff optimization device, which comprises:

the acquisition module is used for acquiring a random access trigger reason, an RAR Backoff value and a timer running state of a current RRC layer when the random access failure is detected;

a determining module, configured to determine a target Backoff duration based on the random access trigger cause, the RAR Backoff value, and a timer operating state of the current RRC layer;

and the initiating module is used for initiating the random access again in different modes according to the target Backoff duration. Based on the above embodiments, the same parts of the apparatus as those of the above method are not discussed.

In one embodiment, the determining module is further configured to:

In one embodiment, the initiating module is configured to:

if the data transmission is not canceled, determining whether to search an available adjacent area or not by combining the running state of a T300/T301/T304/T319 timer of an RRC layer;

In one embodiment, the search module is configured to:

It will be clear to those skilled in the art that, for the convenience and simplicity of description, the above division of the program modules is merely used as an example, and in practical applications, the above function distribution may be performed by different program modules according to needs, that is, the internal structure of the device is divided into different program units or modules to perform all or part of the above described functions. In the embodiments, each program module may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one processing unit, and the integrated units may be implemented in a form of hardware, or in a form of software program unit. In addition, specific names of the program modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or recited in detail in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described embodiments are merely exemplary, and the division of the modules or units is merely an example of a logical division, and there may be other divisions when the actual implementation is performed, and illustratively, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed coupling or direct coupling or communication connection between each other may be through some interfaces, or indirect coupling or communication connection between units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method for backoff optimization of random access, comprising:

when detecting the random access failure, acquiring a random access trigger reason, an RAR Backoff value and a timer running state of a current RRC layer;

2. The method according to claim 1, wherein when detecting a random access failure, obtaining a random access trigger cause, a RAR Backoff value, and a timer operating state of a current RRC layer, and determining a target Backoff duration comprises:

3. A Backoff optimization method for random access according to claim 1, wherein said re-initiating random access in different manners according to the target Backoff duration comprises:

4. A Backoff optimization method for random access according to claim 1, wherein said re-initiating random access in different manners according to the target Backoff duration comprises:

if the random access is triggered by the application layer data, canceling the data transmission when the residual effective duration of the application layer data is less than or equal to the target Backoff duration, otherwise not canceling the data transmission;

5. The method of claim 4, wherein the determining whether to search for the available neighbor cell in conjunction with the running state of the T300/T301/T304/T319 timer of the RRC layer if the data transmission is not cancelled comprises:

if the terminal is in the RRC switching process and the residual time length of the T304 is less than or equal to the target Backoff time length, ending the RRC switching process and searching the available adjacent cell;

otherwise, the available neighbor cell is not searched.

6. An apparatus for backoff optimization for random access, comprising:

7. The apparatus for backoff optimization for random access of claim 6, wherein the determining module is further configured to:

8. The apparatus for backoff optimization of random access according to claim 6, wherein said initiating module is configured to:

9. The apparatus for backoff optimization of random access according to claim 6, wherein said initiating module is configured to:

10. A backoff optimizing device for random access according to claim 9, comprising a searching module configured to: