Carrier Aggregation Downlink Data Splitting Method

Abstract

The present invention discloses a method for downlink data splitting in carrier aggregation. The method includes: splitting downlink data at the PDCP layer, with one path split to the RLC layer of the primary cell and the other path split to the RLC layer of the secondary cell. The RLC layers of the primary cell and the secondary cell have shared memory. At the RLC layer, the downlink data scheduled for the MAC layer is respectively marked with a first tag and a second tag. The data packet marked with the first tag is sent to the MAC layer of the primary cell, and the data packet marked with the second tag is sent to the MAC layer of the secondary cell. The present invention can effectively reduce the packet out-of-order problem generated by carrier aggregation splitting at the PDCP layer and the RLC layer. The present invention can be widely applied to the field of carrier aggregation technology.

Description

Technical Field

[0001] The present invention relates to the technical field of carrier aggregation, and in particular to a method for downlink data splitting in carrier aggregation. Background Art

[0002] During the existing downlink process of carrier aggregation data, the RLC layer of the primary cell determines the amount of data in the RLC layer buffer of the carrier aggregation bearer allocated to the RLC layer of the primary cell and the secondary cell, and sends the amount of data in the RLC layer buffer allocated to the secondary cell to the MAC layer of the secondary cell. Then, the RLC layer of the primary cell determines the amount of data requested by the primary cell side from the RLC layer of the primary cell and the amount of data requested by the secondary cell side from the RLC layer of the primary cell. Then, the RLC layer of the primary cell allocates data according to the amount of data requested by the primary cell side and the secondary cell side, and forms the allocated data into RLC PDUs and sends them to the MAC layer of the primary cell and the MAC layer of the secondary cell respectively.

[0003] In the above process, when the RLC layer data of the primary cell is sent to the MAC layer for real-time scheduling, it is possible that the data packets to be scheduled to the MAC layer of the secondary cell are distributed to the MAC layer of the primary cell, resulting in an out-of-order situation where the sequence numbers of the data packets scheduled to the MAC layer of the primary cell are 1, 3, 5, 7, and the sequence numbers of the data packets scheduled to the MAC layer of the secondary cell are 2, 4, 6, 8. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, an object of the present invention is to provide a method for downlink data splitting in carrier aggregation, which can avoid the technical problem of out-of-order data in the MAC layer when downlink data is scheduled from the RLC layer to the MAC layer.

[0005] The technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for downlink data splitting in carrier aggregation. The method includes: according to the bandwidths of the primary and secondary cells and the UE scheduling capabilities, the PDCP layer of the primary cell splits the downlink data, with one path being split to the RLC layer of the primary cell and the other path being split to the RLC layer of the secondary cell. Among them, the downlink data is sorted during the splitting process to form data packets with serial numbers in a sequential order, and the RLC layer of the primary cell and the RLC layer of the secondary cell have shared memory; when the first data packet of the RLC layer of the primary cell is scheduled to the MAC layer of the primary cell, the RLC layer of the primary cell determines whether the first data packet is a data packet to be scheduled by the secondary cell. If so, the first data packet is skipped and a message is sent to the secondary cell; if not, the first data packet is marked with a first mark, and subsequently, the first data packet marked with the first mark is sent to the MAC layer of the primary cell; when the second data packet of the RLC layer of the secondary cell is scheduled to the MAC layer of the secondary cell, the RLC layer of the secondary cell determines whether the second data packet is a data packet to be scheduled by the primary cell. If so, the second data packet is skipped and a message is sent to the primary cell; if not, the second data packet is marked with a second mark, and subsequently, the second data packet marked with the second mark is sent to the MAC layer of the secondary cell.

[0007] The beneficial effects of the present invention are:

[0008] By using the shared memory of the RLC layer of the primary cell and the RLC layer of the secondary cell in the present invention, when the downlink data is scheduled from the shared memory to the MAC layer of the secondary cell, since the packets to be scheduled by the primary cell later have been marked with the first mark, during real-time scheduling, the scheduling starts from the marked data packets. Thus, it is ensured that the SN numbers of the data packets scheduled to the MAC layer of the primary cell are consecutive 1, 2, 3, 4, and the SN numbers of the data packets scheduled to the MAC layer of the secondary cell are consecutive 5, 6, 7, 8. In this way, the problem of out-of-order packets generated by the RLC layer due to carrier aggregation splitting can be effectively reduced.

[0009] At the same time, the present invention also solves the problem of out-of-order packets caused by the splitting of the PDCP layer. The downlink data is aggregated and processed at the RLC layer, which can solve the problem of out-of-order packets at the PDCP layer. Subsequently, it can be evolved to the situation where the amount of data sent by the PDCP layer can be scheduled to the MAC layer at one time. Description of the Drawings

[0010] Figure 1 is a schematic flowchart of an embodiment of a method for downlink data splitting in carrier aggregation according to the present invention;

[0011] Figure 2 is a schematic structural diagram of an embodiment of a method for downlink data splitting in carrier aggregation according to the present invention. Detailed Embodiments

[0012] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0013] Please refer to Figure 1 and Figure 2 . As Figure 1 shown, the method includes the following steps:

[0014] S11: According to the bandwidths of the primary cell and the secondary cell and the UE scheduling capability, the PDCP layer of the primary cell splits the downlink data. One path is split to the RLC layer of the primary cell, and the other path is split to the RLC layer of the secondary cell. Among them, during the splitting process, the downlink data is sorted to form data packets with serial numbers in a sequential order. The RLC layer of the primary cell and the RLC layer of the secondary cell have shared memory;

[0015] As Figure 2 shown, the downlink data is sent from the ng (5G core network) or s1 (4G core network) to the PDCP layer, and the PDCP layer further splits the downlink data into two paths. One path goes to the RLC layer of the primary cell, and the other path goes to the RLC layer of the secondary cell.

[0016] Among them, there are at least three ways of splitting, and the three ways are as follows:

[0017] First, default ratio 1:1 splitting. That is, the data packets with odd serial numbers are sent to the RLC layer of the primary cell, and the data packets with even serial numbers are sent to the RLC layer of the secondary cell.

[0018] Second, configured ratio splitting. That is, the m data packets with serial numbers from 0 to m - 1 are sent to the RLC layer of the primary cell; for the secondary cell, the n data packets with serial numbers from m to m + n are sent to the RLC layer of the secondary cell, and the total number of packets is m + n. When m = n, it is equivalent to 1:1 splitting.

[0019] Third, splitting according to bandwidth capabilities. If the bandwidth of the primary cell is 100M and the bandwidth of the secondary cell is 60M, then split according to 100:60 or 50:30.

[0020] For the packets in sequence at the PDCP layer, the serial numbers received by the RLC layer after splitting are out of order; then, the downlink data continues to converge at the RLC layer. Because the RLC layer has a cache, after a period of time, the data packets sent by the PDCP layer will be saved to the corresponding cache chain of the RLC layer according to the SN (serial number), which is equivalent to sorting.

[0021] It should be noted here that the RLC layer of the primary cell and the RLC layer of the secondary cell use shared memory, so that there is only one data cache chain in the RLC layer, and the scheduling of the MAC layers of the primary and secondary cells can be seen and scheduled to the corresponding layer of the peer UE for processing.

[0022] S12: When scheduling the first data packet of the RLC layer of the primary cell to the MAC layer of the primary cell, the RLC layer of the primary cell determines whether the first data packet is the data packet to be scheduled by the secondary cell. If so, skip the first data packet and send a message to the secondary cell; if not, mark the first data packet with a first flag, and subsequently send the first data packet marked with the first flag to the MAC layer of the primary cell.

[0023] S13: When scheduling the second data packet of the RLC layer of the secondary cell to the MAC layer of the secondary cell, the RLC layer of the secondary cell determines whether the second data packet is the data packet to be scheduled by the primary cell. If so, skip the second data packet and send a message to the primary cell; if not, mark the second data packet with a second flag, and subsequently send the second data packet marked with the second flag to the MAC layer of the secondary cell.

[0024] Step S12 and step S13 are parallel steps, and their order can be swapped.

[0025] Among them, since the RLC layer of the primary cell and the RLC layer of the secondary cell use shared memory, the contents of the first data packet and the second data packet are the same.

[0026] It should be noted that the first flag and the second flag are different. For example, set the first flag as pcellSched = 1, and set the second flag as scellSched = 1.

[0027] During subsequent packet assembly, packet assembly is performed in sequence by combining the first flag, the second flag, and the sequence number of the data packet. If packet assembly is performed on the data scheduled for the primary cell, the data packets with the first flag are packet-assembled in sequence number order. If packet assembly is performed on the data scheduled for the secondary cell, the data packets with the second flag are packet-assembled in sequence number order.

[0028] During retransmission (transferring data from the primary RLC layer to the MAC layer), retransmission is performed according to the protocol, and it can also ensure that the retransmission SN numbers are continuous.

[0029] The above has specifically described the preferred embodiments of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art can also make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A carrier aggregation downlink data offloading method, characterized in that: include: According to the bandwidth of the primary and secondary cells and the UE scheduling capability, the PDCP layer of the primary cell splits the downlink data, one way is split to the RLC layer of the primary cell, and the other way is split to the RLC layer of the secondary cell, wherein the downlink data is sorted in the splitting process to form data packets with sequence numbers in a sequential order, and the RLC layer of the primary cell and the RLC layer of the secondary cell have a shared memory; When scheduling a first data packet of the RLC layer of the primary cell to the MAC layer of the primary cell, the RLC layer of the primary cell determines whether the first data packet is a data packet to be scheduled by the secondary cell, and if so, skips the first data packet and sends a message to the secondary cell; if not, marks the first data packet with a first mark, and subsequently sends the first data packet marked with the first mark to the MAC layer of the primary cell; When scheduling the second data packet of the RLC layer of the secondary cell to the MAC layer of the secondary cell, the RLC layer of the secondary cell determines whether the second data packet is the data packet to be scheduled by the primary cell. If so, the second data packet is skipped and a message is sent to the primary cell; if not, the second data packet is marked with a second mark, and the second data packet marked with the second mark is subsequently sent to the MAC layer of the secondary cell.

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