CN113411910A

CN113411910A - Scheduling mechanism for accelerating 5G-NR random access

Info

Publication number: CN113411910A
Application number: CN202110965208.7A
Authority: CN
Inventors: 刘宁
Original assignee: Sichuan Innogence Technology Co Ltd
Current assignee: Sichuan Innogence Technology Co Ltd
Priority date: 2021-08-23
Filing date: 2021-08-23
Publication date: 2021-09-17

Abstract

The invention discloses a scheduling mechanism for accelerating 5G-NR random access, which comprises the following steps: step 1: scheduling RRC establishment messages for the UE; step 2: pre-estimating the time of the uplink message prepared by the UE, calculating the time of the next SR period of the UE, and reading a pre-scheduling threshold value; and step 3: judging whether the time of the uplink message prepared by the UE and the time distance of the next SR period of the UE are greater than a pre-scheduling threshold or not; and 4, step 4: if so, calculating the time when the pre-scheduling is sent to the UE and recording; if the number of the SR messages is smaller than the preset value, no processing is performed, and the UE is waited to send the SR; the pre-scheduling is pre-determined according to the 3GPP protocol flow, and the time when the UE will generate uplink data is obtained so as to carry out efficient pre-scheduling. The invention makes full use of the base station side to pre-judge the information of the user, and only performs accurate pre-scheduling when the pre-scheduling is needed; the user random access process is accelerated with minimum overhead.

Description

Scheduling mechanism for accelerating 5G-NR random access

Technical Field

The invention relates to the technical field of wireless communication, in particular to a scheduling mechanism for accelerating 5G-NR random access.

Background

The random access procedure is a very important procedure in a mobile communication system. In order to connect to the network, the UE needs to acquire uplink and downlink time synchronization with the network. In downlink synchronization, the UE may acquire relative time and cell basic information by demodulating the SSB, and then obtain more cell information including related parameters of an uplink Physical Random Access Channel (PRACH) by reading the SIB1 message, and at this time, may initiate a random access preamble. When the base station side detects the random access preamble of the UE, the uplink time deviation of the UE and the base station can be estimated, the base station can tell the UE that the time of the UE is adjusted by replying a random access response to the UE, so that uplink time synchronization is achieved, and the base station can allocate time-frequency resources required by the next uplink message to the UE in the random access response.

And then the UE can initiate an RRC establishment request, the base station sends a competition conflict solution and an RRC establishment message after detecting the RRC establishment request, and the UE replies an RRC establishment completion message after receiving the competition conflict solution and the RRC establishment message of the UE, so that the UE and the base station completely establish a first RRC channel, the random access process is finished, and the UE is successfully accessed to the base station.

When each information exchange between the base station and the UE is turned on, there are 8 message exchanges in total for one random access, as shown in fig. 1.

And 4 and 5, simultaneously sending the messages to the UE through one message, or splitting the messages into 2 messages to send the messages to the UE. After receiving the messages 4 and 5, the UE can prepare to report the RRC setup complete after processing the message content, i.e. step 8. But the UE needs the base station to give uplink scheduling to transmit uplink data at the scheduled time and the scheduled resource. For example, the uplink scheduling resource required in step 3 is carried in the message content in step 2.

The UE sends an uplink Scheduling Request (SR) periodically, and the period and the resource for sending the SR are carried in the RRC establishment message. At this time, the UE needs to wait for its SR transmission cycle, and after reaching its own transmission time, it transmits the SR, that is, step 6. And after the base station resolves the SR, scheduling the uplink resource for the UE and sending the uplink resource to the UE through the DCI-0, namely step 7. The UE may then proceed to step 8 to complete the entire random access.

The least stable overall process time is between step 5 and step 6. Generally, the SR period allocated to a user by a base station is not too small, because the PUCCH resources for transmitting SR are limited, and these resources are required for multiple users, so that the total number of users supported is reduced if the period is too small. Typical configuration values are compared, such as 160 slots, or more (to support a larger number of connected users). That is, in the worst case, after the UE processes the RRC setup message, prepares the RRC setup complete message, prepares to send to the base station, and needs to wait 8ms or more to send its own SR, and the base station receives the SR and then sends DCI-0 to the UE.

It can be seen from the log of the real UE side that after the UE receives the message of step 5, within 0.5ms, the contents of step 6 and step 8 are prepared, and then the UE starts to wait for the timing of sending step 6. When the time for transmitting the SR arrives, step 6 cannot be performed, and step 7 and step 8 can be completed within 0.5 ms. Therefore, the time from the UE receiving the message of step 5 to the UE performing step 6 is the most time-consuming and most uncontrollable place in the access procedure.

A method and an apparatus for accelerating RRC connection establishment are disclosed in patent application No. cn200810002522.x, the method includes: receiving an uplink RRC message sent by UE; when the base station of the target cell does not have the context of the UE, sending a message carrying random access related parameters required by RRC establishment to the UE, and the UE initiating an RRC establishment process according to the random access related parameters, so that the RRC connection establishment time can be greatly reduced, the network load can be balanced, and the UE can switch method processes among systems of different systems, so that the RRC establishment time can be effectively reduced, the service interruption time can be reduced, the user experience can be effectively improved, the load condition of the network can be effectively balanced, and the network can operate more stably. The scheme mainly aims at that in the switching process of the UE between the base stations, the UE is switched from the original station to the target station, and because the target station does not have the basic information of the UE, the scheme sends some information of the target station to the UE from the original station before the switching, so that the speed of establishing RRC by the UE at the target station can be accelerated, and a plurality of load balance related optimizations are derived; the main optimization point is that the upper layer (RRC layer, RRM layer, etc.) does not care about the time delay and flow on the physical layer and MAC layer; the scheme is based on that before UE is switched, an original station should send messages related to a target station to the UE, so that the UE can acquire various information of the target station step by step without being completely as long as initial access in the switching process; the optimization is performed at the high layer (RRC layer), so that the high layer flow in the switching process is less and faster. Without any flow optimization for the communication bottom layers (physical layer and MAC layer).

Disclosure of Invention

The invention aims to overcome the defects of the prior art, pre-judges the information of a user by using a base station side, and only performs accurate pre-scheduling when the pre-scheduling is needed, thereby providing a scheduling mechanism for accelerating 5G-NR random access.

The purpose of the invention is realized by the following technical scheme:

a scheduling mechanism for accelerating 5G-NR random access, comprising the following steps:

step 1: scheduling RRC establishment messages for the UE; UE is user terminal equipment of a cellular wireless network, and RRC is a radio resource control message;

step 2: pre-estimating the time of the uplink message prepared by the UE, calculating the time of the next SR period of the UE, and reading a pre-scheduling threshold value;

and step 3: judging whether the time of the uplink message prepared by the UE and the time distance of the next SR period of the UE are greater than a pre-scheduling threshold or not; SR is a user scheduling request;

and 4, step 4: if so, calculating the time when the pre-scheduling is sent to the UE and recording; if the SR is smaller than the preset value, no processing is carried out, and the UE is waited to send the SR.

Further, the pre-scheduling is performed only once.

Further, the pre-scheduling is pre-determined according to the 3GPP protocol flow, and obtains when the UE will generate uplink data for efficient pre-scheduling.

Further, in step 4, after calculating at what time the pre-scheduling is sent to the UE, the pre-scheduling time and the scheduled resource size are recorded.

Further, the size of the scheduled resource is allocated according to an RRC establishment complete message.

Further, a scheduling mechanism for accelerating 5G-NR random access further includes uplink scheduling at TTI, where TTI is a transmission time interval, and the uplink scheduling at TTI specifically includes: and calculating the predicted uplink data time point of the user and the time distance of the user to the next SR cycle to judge whether to perform pre-scheduling.

The invention has the beneficial effects that: the invention makes a prejudgment on the information of the user by fully utilizing the base station side, and only carries out accurate pre-scheduling when the pre-scheduling is needed; the user random access process is accelerated by using the minimum overhead; under the condition that resources are limited and the number of total users supported is not influenced, the access of the users is quickly completed, and the time for pre-scheduling is reduced.

Drawings

Fig. 1 is a flow chart of random access link establishment.

Fig. 2 is a flow chart of the method of the present invention.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.

Embodiment 1, as shown in fig. 2, a scheduling mechanism for accelerating 5G-NR random access includes the following steps:

the method comprises the following steps:

step 1: scheduling RRC establishment messages for the UE;

step 2: pre-estimating the time of the uplink message prepared by the UE, calculating the time distance of the next SR period of the UE, and reading a pre-scheduling threshold value;

and step 3: judging whether the time distance between the time when the UE prepares the uplink message and the time when the UE performs the next SR cycle is larger than a pre-scheduling threshold or not;

The UE is user terminal equipment of a cellular wireless network; RRC is a radio resource control message; the SR is a user scheduling request and represents a signal; the SR period indicates a period in which such a signal is transmitted.

Further, the pre-scheduling is performed only once.

The time distance is the absolute value of the time difference.

The invention can solve the problem that in some cases, the UE already prepares the uplink message, but needs to wait for the next SR cycle to send the request. In addition, the invention does not simply and directly carry out pre-scheduling, because a large amount of resources are wasted, and relatively, the invention fully utilizes the base station side to carry out pre-judgment on the information of the user, and only carries out accurate pre-scheduling when the pre-scheduling is needed. The user random access process is accelerated with minimum overhead.

The key points of the invention are as follows: according to the random access procedure shown in fig. 1: after the base station sends the RRC setup message to the user (step 5), the base station side can predict how long the UE should be ready for the message of step 8, that is, the base station can predict when the UE wants to send step 6, but the UE needs to wait for its SR period, and the base station also knows that the UE wants to reply the RRC setup complete message, and the size of the message is also known. In the scheme of the invention, the base station side calculates and calculates the time distance from the current UE to the next SR period at the predictable time points, if the distance is more than a certain threshold, the base station side directly issues an uplink scheduling to the UE (step 7). So that the UE can directly initiate step 8 and skip step 6.

The method is an idea of uplink pre-scheduling, but compared with the traditional pre-scheduling, the method does not always pre-schedule the user so as to waste PDCCH resources seriously. In contrast, in the present scheme, in the random access process, a prejudgment is performed according to the 3GPP protocol flow, and it is known when the user will generate uplink data, so that efficient pre-scheduling is performed (at most, one-time pre-scheduling is performed).

Example 2: a scheduling mechanism for accelerating 5G-NR random access, comprising the following steps:

step 1: scheduling RRC establishment messages for the UE;

and step 3: judging whether the time of the uplink message prepared by the UE and the time distance of the next SR period of the UE are greater than a pre-scheduling threshold or not;

Further, the pre-scheduling is performed only once.

Further, a scheduling mechanism for accelerating 5G-NR random access further includes uplink scheduling in TTI, where the uplink scheduling in TTI specifically is: and calculating the predicted uplink data time point of the user and the time distance of the user to the next SR cycle to judge whether to perform pre-scheduling.

The invention also calculates the predicted uplink data time point of the user and the time distance from the user to the next SR cycle of the user to judge whether to perform pre-scheduling, thereby further reducing the pre-scheduling time and only performing the pre-scheduling on the scene which can really and obviously accelerate the random access process.

The specific flow of uplink scheduling in TTI is as follows:

1) detecting whether the current UE has an SR scheduling request, if so, normally performing uplink scheduling according to an SR process;

2) if the current UE has no SR scheduling request, detecting whether the current UE has single pre-scheduling enabling, and checking whether the current UE is the current TTI;

3) if the current TTI is the current TTI with the single pre-scheduling enabling, performing uplink scheduling according to the parameter configuration of the single pre-scheduling; otherwise, the uplink scheduling of the current UE is abandoned.

For example, for the RRC setup complete message, the UE may actually send the next radio frame after receiving the MSG4 according to the measurement result.

However, sometimes, the SR may be transmitted after waiting for the SR period, so that the SR may be transmitted after obtaining uplink scheduling.

While a typical periodic configuration of SR, say 2240 (symbol), is 160 slots, 8ms, i.e. theoretically the UE may need more than 7ms to send out the prepared MSG 5.

If the SR cycle configuration is larger, it may wait longer. On the basis of the method, the time of the UE at the step can be uniformly controlled to be about 0.5 ms.

At the MAC layer of the base station, the following process is performed:

1. after sending the RRC setup message to the user, it starts to predict when the UE can prepare the RRC setup complete message, for example, 10 slots.

2. And reading the SR period parameter of the current user, and calculating the distance (slot is a unit) from the next SR period of the UE by taking the estimated time point when the UE prepares the RRC establishment completion message as a starting point.

3. And reading a pre-scheduling threshold, and judging whether the distance calculated in the previous step is greater than the threshold.

4. If less than the threshold, then any pre-scheduled actions are aborted. Otherwise, calculating when to do single pre-scheduling for the UE, and recording the time of the single scheduling and the scheduled resource size (allocated according to the RRC establishment completion message).

In the uplink scheduling flow of each TTI (transmission time interval), the following processing is performed:

1. and detecting whether the current UE has an SR request, and if so, going through a normal SR scheduling process.

2. If the UE does not have the SR scheduling request, it is detected whether the UE has single prescheduling enable in the above procedure, and it is checked whether it is the current TTI. And if all the conditions are not met, abandoning the uplink scheduling of the current UE.

3. And if the conditions in the last step are met, performing uplink scheduling according to the parameters of single pre-scheduling.

The optimization point of the scheme is that in a normal access process, in the process of establishing the first RRC, due to the disadvantage of the protocol flow, the UE and the base station may be ready to do the next step (and both sides also know that the other side is ready), but a waiting period is needed to complete the next step. The time waste caused by the scheme can be reduced to the minimum, and the unnecessary overhead is almost avoided. It mainly consists in flow optimization on the communication bottom layer (physical layer and MAC layer).

In the scheme, attention is mainly paid to a method for effectively and efficiently avoiding unstable time delay caused by an SR period in one access process (which can be initial access or handover access), so as to shorten the access time.

The invention makes a prejudgment on the information of the user by fully utilizing the base station side, and only carries out accurate pre-scheduling when the pre-scheduling is needed; the user random access process is accelerated by using the minimum overhead; under the condition that resources are limited and the number of total users supported is not influenced, the access of the users is quickly completed, and the time for pre-scheduling is reduced.

It should be noted that, for simplicity of description, the above-mentioned embodiments of the method are described as a series of acts or combinations, but those skilled in the art should understand that the present application is not limited by the order of acts described, as some steps may be performed in other orders or simultaneously according to the present application. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and elements referred to are not necessarily required in this application.

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

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a ROM, a RAM, etc.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A scheduling mechanism for expediting 5G-NR random access, comprising the steps of:

step 2: pre-estimating the time of UE for preparing uplink messages, calculating the time of the next SR period of the UE, and reading a pre-scheduling threshold value; SR is a user scheduling request;

and step 3: judging whether the time distance between the time when the UE prepares the uplink message and the time when the UE performs the next SR cycle is larger than a pre-scheduling threshold value or not;

and 4, step 4: if so, calculating the time for sending the pre-scheduling to the UE; if the SR is smaller than the preset value, no processing is carried out, and the UE is waited to send the SR.

2. The scheduling mechanism for accelerating 5G-NR random access according to claim 1, wherein the pre-scheduling is performed only once.

3. The scheduling mechanism of claim 1 wherein the pre-scheduling is performed according to 3GPP protocol flow to obtain when the UE will generate uplink data for efficient pre-scheduling.

4. The scheduling mechanism of claim 1, wherein after calculating the pre-scheduled time for UE transmission in step 4, the pre-scheduled time and the scheduled resource size are recorded.

5. The scheduling mechanism for accelerating 5G-NR random access according to claim 1, wherein the scheduled resource size is allocated according to RRC setup complete message.

6. The scheduling mechanism for accelerating 5G-NR random access according to claim 1, further comprising an uplink scheduling in TTI, where TTI is a transmission time interval, and the uplink scheduling in TTI specifically is: and calculating the predicted uplink data time point of the user and the time distance of the user to the next SR cycle to judge whether to perform pre-scheduling.