CN111935794B

CN111935794B - Data processing method for shortening switching time delay

Info

Publication number: CN111935794B
Application number: CN202010627779.5A
Authority: CN
Inventors: 吕磊
Original assignee: Sichuan Innogence Technology Co Ltd
Current assignee: Sichuan Innogence Technology Co Ltd
Priority date: 2020-07-02
Filing date: 2020-07-02
Publication date: 2021-06-04
Anticipated expiration: 2040-07-02
Also published as: CN111935794A

Abstract

The invention discloses a data processing method for shortening switching time delay, when user equipment is switched, if a target side F1-U link is successfully established and user data sending conditions are met, sending a certain amount of data to a target DU side, and caching downlink data and preprocessing by an RLC layer of the target DU side; meanwhile, when the UE sends a PDCP status report at the target DU side, the RLC layer of the target DU side analyzes a message of which the RLC SN is equal to 0, namely the PDCP status report, and processes the PDCP status report; meanwhile, a PDCP status report is delivered to the PDCP layer. Therefore, during switching, the PDCP layer does not need to wait and process the PDCP status report and then sends data to the RLC layer at the target DU side, but when the F1-U link is successfully established, the data is immediately sent to the RLC and is preprocessed, so that the time overhead of sending the PDCP status report to the PDCP layer by the DU side, processing the PDCP status report by the PDCP layer and sending the data to the RLC layer at the target DU side by the PDCP layer during switching is eliminated, the switching time delay is shortened, and the user experience is improved.

Description

Data processing method for shortening switching time delay

Technical Field

The invention relates to a data processing method, in particular to a data processing method for shortening switching time delay, and belongs to the field of wireless communication.

Background

In order to enhance the flexibility of network deployment and meet different requirements in different application scenarios, the 5G radio access network adopts a networking architecture in which a Central Unit (CU) and a Distributed Unit (DU) are independently deployed. Further, in order to support functions such as wireless network slicing, a CU clouding deployment mode is proposed. The CU is deployed in the data center, the DU is deployed at the site, and the CU and the DU are connected through the optical fiber. However, the networking mode of independent deployment of the CUs and the DUs necessarily causes additional data transmission delay between the CUs and the DUs, and in the CU clouded deployment scenario, the data transmission delay is further deteriorated. However, in the 5G wireless access network, the data transmission delay is one of the key indexes, especially for the application scenarios such as ultra-high reliability and low-delay communication.

Furthermore, when a User Equipment (UE) moves from its serving cell to another cell, the UE needs to initiate access on the target DU side. When the UE is successfully accessed at the target DU side, the uplink and downlink data can be normally transmitted. Under different scenes, the base station sends downlink data at different times on the target DU side. Scene one: when a Packet Data Convergence Protocol (PDCP) status report is not needed, the CU side may send downlink Data to the target DU side before and after receiving a downlink Data delivery status indication of the target DU side, and wait for scheduling. Scene two: when the PDCP status report is needed, the CU side needs to receive and process the PDCP status report sent by the UE, and then sends downlink data to the target DU side to wait for scheduling.

In scenario two, the UE must undergo the following processes when receiving the first packet data on the target DU side: 1) UE successfully accesses the target DU side; 2) UE sends an uplink PDCP status report; 3) the target DU side sends the PDCP status report to the CU side through a F1 User plane interface (F1 User plane interface, F1-U); 4) a CU side User Plane (CU-UP) processes the PDCP status report; 5) and under the condition that the sending condition is met, sending the downlink data to the target DU side and waiting for scheduling.

However, in the scenario of separate deployment of CU and DU, the time consumed by steps 3-5 becomes non-negligible, and it is necessary to prolong the time for UE to receive the first packet data at the target DU side, thereby deteriorating the user experience. However, currently, the research on handover mainly focuses on success rate, control signaling and the like, and does not focus on user data transmission delay.

Disclosure of Invention

In order to solve the problem of user data interruption during switching, the invention provides a data processing method for shortening switching time delay.

The technical scheme adopted by the data processing method for shortening the switching time delay is as follows:

a data processing method for shortening switching time delay is characterized in that when user equipment is switched, if a target side F1-U link is successfully established and user data sending conditions are met, a certain amount of data is sent to a target DU side, and an RLC layer of the target DU side caches downlink data and carries out preprocessing. Meanwhile, when the UE sends a PDCP status report on the target DU side, the RLC layer of the target DU side parses a packet whose RLC SN is equal to 0, that is, the PDCP status report, and processes the PDCP status report. Meanwhile, a PDCP status report is delivered to the PDCP layer.

Further, the user data transmission condition refers to that, in an intra-station switching scenario, when the link establishment between CU-UP and the target DU side F1-U is successful, data is transmitted to the target DU side. And under the inter-station switching scene, when the target CU-UP side receives the SN transmission information of the source side PDCP layer and the link between the target CU-UP and the target DU side F1-U is successfully established, sending data to the target DU side.

The sending of a certain amount of data to the target DU side means that the sent data amount cannot exceed the sending window of the PDCP layer, thereby avoiding the out-of-sync of the PDCP layer hyper frame number. And under the scene of no need of PDCP status report, sending data to all corresponding RLC entities at the target DU side. In the PDCP status report scene, when one PDCP entity corresponds to a plurality of RLC entities, only sending data to a main RLC entity; and when the PDCP layer receives and processes the PDCP status report, the data is sent to all corresponding RLC entities.

The target DU side RLC layer preprocessing data means that RLC SDU is immediately assembled into RLC PDU without a PDCP status report scene, and the scheduling of a Media Access Control (MAC) layer is waited; and under the condition that the PDCP state report exists, the target DU side RLC layer assembles the RLC SDU into the RLC PDU without filling the RLC SN.

The target DU side RLC layer processing PDCP status report means that the UE side PDCP layer which is cached by the RLC layer is deleted according to the PDCP status report and successfully receives the message, so that the empty transmission repeated message is minimized, and the frequency spectrum efficiency is improved. And for the buffer messages which are not deleted, allocating RLC SN and waiting MAC scheduling.

The invention has the beneficial effects that: when switching, the PDCP layer does not need to wait and process the PDCP status report and then send data to the RLC layer of the target DU side, but when the F1-U link is successfully established, the data is immediately sent to the RLC layer and is preprocessed, so that the time overhead of the PDCP status report processing by the PDCP layer and the data sending by the PDCP layer to the RLC layer of the target DU side when switching is eliminated, thereby shortening the switching time delay and improving the user experience.

Drawings

Other features and advantages of the invention will be apparent from the following description of the preferred embodiments of the invention, taken in conjunction with the accompanying drawings and from the claims. Individual features of the different embodiments shown in the figures may be combined in any desired manner in this case without going beyond the scope of the invention. In the drawings:

fig. 1 is a schematic diagram of a data processing flow for shortening a handover delay.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Examples

In this embodiment, a data processing method for shortening the handover delay is disclosed, when the target side F1-U link is successfully established and the data transmission condition is satisfied during handover, the data is immediately transmitted to the target DU side RLC layer without waiting for the PDCP status report. After receiving the downlink data, the target DU side RLC layer caches the data and performs preprocessing. When the UE is successfully accessed at the target DU side, if necessary, the UE sends an uplink PDCP status report, the RLC layer of the target DU side analyzes the PDCP status report, deletes the successfully received message of the UE according to the PDCP status report, distributes RLC SN, and waits for MAC scheduling. Meanwhile, the target DU side RLC layer delivers a PDCP status report to the PDCP layer. Therefore, the transmission time of the PDCP status report and the user data at the F1-U port during switching is eliminated, the switching time delay is shortened, and the user experience is improved.

The data processing flow for shortening handover in the embodiment of the present invention is shown in fig. 1, and specifically includes the following steps:

step 1, during switching. When the CU Control Plane (CU-CP) successfully establishes a new F1-U tunnel between the CU-UP and the target DU. In addition, in the inter-station handover scenario, the condition for sending data to the target DU is met only when the source side PDCP layer SN transmission information needs to be received.

And step 2, checking whether one PDCP entity corresponds to a plurality of target side RLC entities. If the plurality of RLC entities are corresponded, and when a PDCP status report exists, only sending data to a main RLC entity; otherwise, the data is sent to all corresponding RLC entities.

And step 3, the target side RLC entity caches the downlink data and carries out preprocessing.

And 4, checking whether a PDCP status report exists by the target side RLC entity. If no PDCP status report exists, RLC SN is distributed, RLC SDU is packaged into RLC PDU, and MAC scheduling is waited. Otherwise, the target side main RLC entity analyzes that the UE sends a PDCP status report, deletes the UE successfully received messages cached locally according to the PDCP status report, distributes RLC SNs for the messages which are not deleted, and waits for MAC scheduling.

And step 5, the main RLC entity at the target side delivers a PDCP status report to the PDCP layer through the port F1U.

And step 6, the PDCP layer processes the PDCP status report and sends data to all target side RLC entities corresponding to the PDCP entity.

And 7, the subsequent data transmission flow is consistent with the normal data transmission flow. That is, the PDCP layer assembles PDCP SDUs into PDCP PDUs and transmits them to the RLC layer, which allocates RLC SNs to the received RLC SDUs and assembles them into RLC PDUs. And finally, waiting for the MAC layer to schedule.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. A data processing method for shortening switching time delay is characterized by comprising the following steps:

s1: when user equipment is switched, if a target side F1-U link is successfully established and user data transmission conditions are met, a certain amount of data is transmitted to a target DU side, a target DU side RLC layer caches downlink data and carries out preprocessing, and the data preprocessing mode of the target DU side RLC layer is as follows: under the scene without PDCP status report, RLC SDU is immediately assembled into RLC PDU; in the situation that a PDCP status report exists, the target DU side RLC layer assembles RLC SDU into RLC PDU without filling RLC SN; under the switching scene in the station, the user data sending conditions are as follows: the CU-UP and the target DU side F1-U link are successfully established, and under the scene of switching among stations, the user data sending condition is as follows: the target CU-UP side receives the SN transmission information of the source side PDCP layer, and the target CU-UP and the target DU side F1-U link are successfully established;

s2: meanwhile, when the UE sends a PDCP status report at the target DU side, the RLC layer of the target DU side analyzes a message of which the RLC SN is equal to 0, namely the PDCP status report, and processes the PDCP status report;

s3: meanwhile, a PDCP status report is delivered to the PDCP layer.

2. The data processing method for shortening switching delay according to claim 1, wherein the step S1 further comprises the sub-step S103: the sent data volume cannot exceed the sending window of the PDCP layer, and the phenomenon that the PDCP layer exceeds the frame number is avoided; under the scene of no need of PDCP status report, the PDCP layer sends data to all corresponding RLC entities of a target DU side; under the situation that a PDCP status report exists, when one PDCP entity corresponds to a plurality of RLC entities, only sending data to a main RLC entity at a target DU side; and when the PDCP layer receives and processes the PDCP status report, sending data to all corresponding RLC entities of the target DU side.

3. The data processing method for shortening switching delay according to claim 1, wherein the step S2 further comprises the sub-step S201: the method for processing the PDCP status report by the RLC layer at the target DU side comprises the following steps: the main RLC entity deletes the PDCP layer of the UE side cached by the RLC layer according to the PDCP status report and successfully receives the message, minimizes the empty transmission repeat message and improves the spectrum efficiency; and for the buffer messages which are not deleted, allocating RLC SN and waiting MAC scheduling.