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EP-4447608-B1 - DUPLICATION AND RLC OPERATION IN NEW RADIO ACCESS TECHNOLOGY

EP4447608B1EP 4447608 B1EP4447608 B1EP 4447608B1EP-4447608-B1

Inventors

  • DECARREAU, Guillaume
  • SEBIRE, BENOIST

Dates

Publication Date
20260513
Application Date
20180306

Claims (6)

  1. A method, comprising: transmitting (550), by a mobile device (10), a packet data convergence protocol, PDCP, protocol data unit, PDU, and a PDCP PDU duplicate, which is a duplicate of the PDCP PDU, over two different carriers, wherein the two different carriers are aggregated carriers, and wherein transmitting comprises submitting the PDCP PDU and the PDCP PDU duplicate to respective ones of two different Radio Link Control, RLC, entities for uplink transmission over a respective one of the two different carriers; and receiving (560) an indication that indicates one of the PDCP PDU and the PDCP PDU duplicate has been correctly transmitted over one of the two different carriers; characterised in that the method comprises: upon receiving the indication, instructing (570) to discard the other one of the PDCP PDU and the PDCP PDU duplicate that was submitted to the other one of the two different RLC entities for transmission over the carrier other than the one of two different carriers with a successful delivery, wherein instructing to discard comprises informing the other one of the two different RLC entities not to transmit the other one of the PDCP PDU and the PDCP PDU duplicate.
  2. The method of claim 1, wherein, when a discard timer expires for a PDCP service data unit, SDU, the mobile device (10) discards the PDCP SDU along with a corresponding PDCP PDU.
  3. The method of claim 1, wherein, when a successful delivery of a PDCP service data unit, SDU, is confirmed by PDCP status report, the mobile device (10) discards the PDCP SDU along with a corresponding PDCP PDU.
  4. A mobile device (10), comprising: means (10D) for transmitting, by the mobile device (10), a packet data convergence protocol, PDCP, protocol data unit, PDU, and a PDCP PDU duplicate, which is a duplicate of the PDCP PDU, over different carriers, wherein the two different carriers are aggregated carriers, and wherein transmitting comprises submitting the PDCP PDU and the PDCP PDU duplicate to respective ones of two different Radio Link Control, RLC, entities for uplink transmission over a respective one of the two different carriers; and means (10D) for receiving an indication that indicates one of the PDCP PDU and the PDCP PDU duplicate has been correctly transmitted over one of the different carriers; characterised in that the mobile device (10) comprises: means (10A, 10B, 10C), upon receiving the indication, for instructing to discard the other one of the PDCP PDU and the PDCP PDU duplicate that was submitted to the other one of the two different RLC entities for transmission over the carrier other than the one of two different carriers with a successful delivery, wherein instructing to discard comprises informing the other one of the two different RLC entities not to transmit the other one of the PDCP PDU and the PDCP PDU duplicate.
  5. The mobile device (10) of claim 4, comprising means (10A, 10B, 10C) for discarding a PDCP service data unit, SDU, along with a corresponding PDCP PDU when a discard timer expires for the PDCP SDU.
  6. The mobile device (10) of claim 4, comprising means (10A, 10B, 10C) for discarding a PDCP service data unit, SDU, along with a corresponding PDCP PDU when a successful delivery of the PDCP SDU is confirmed by PDCP status report.

Description

TECHNICAL FIELD: The teachings in accordance with the exemplary embodiments of this invention relate generally to a novel method to address Packet duplication at a PDCP sublayer and, more specifically, relate to improving radio link control and radio link failure operations when duplication at the PDCP sublayer takes place. This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section. Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows: AMacknowledged modeARQautomatic repeat requestCPTcontrol protocol data unit typeHARQhybrid automatic repeat requestMACmedium access controlMCGmaster cell groupNRnew radioOTAover-the-airPpoll bitPDCPpacket data convergence protocolPDUprotocol data unitRreserved bitRLCradio link controlRLFradio link failureRRCradio resource controlSCsegmentation controlSDUservice data unitSNsequence numberTBtransport blockUMunacknowledged mode In LTE, the radio protocols for the user plane currently consists of three layers: Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC) and Medium Access Control (MAC). The main services or functions of the PDCP sublayer for example include: header compression and decompression, transfer of user data and ciphering & deciphering as well as timer-based SDU discard. When dual connectivity is configured, for a split bearer, PDCP also performs reordering in a continuous manner. These functions rely on a PDCP SN in the PDCP header of each PDCP PDU. In addition, a study item on New Radio Access Technology (NR) has been agreed. One goal of NR is to support the very high bit rates required for 5G. In order to support such bit rates, it was agreed to move concatenation to MAC and reordering to PDCP, leaving to RLC the main functions of error correction and segmentation/re-assembly. Furthermore, to increase reliability as well as potentially decrease latency, packet duplication of packets at the PDCP sublayer was agreed. However, it is noted that a duplication of packets at the PDCP sublayer can lead to possible inefficiencies in RLC operation in AM mode. The example embodiments of the invention as described herein at least work to address operational inefficiencies that can be caused by this duplication of packets associated with PDCP. InterDigital Communications: "Redundancy below PDCP for NR", 3GPP Draft R2-1701183 discusses duplication schemes where a transport block is transmitted over multiple resource sets, and where retransmission of duplicated transport blocks is stopped if the transport block is successfully delivered via one of the multiple resources. SUMMARY: According to an aspect of the invention, there is provided a method as defined by appended independent claim 1. According to another aspect of the invention, there is provided a mobile device as defined by appended independent claim 5. BRIEF DESCRIPTION OF THE DRAWINGS: The foregoing and other aspects of embodiments of this invention are made more evident in the following Detailed Description, when read in conjunction with the attached Drawing Figures, wherein: Figure 1 shows C-Plane connectivity of eNBs involved in Dual Connectivity as in Figure 4.9.3.1-1 of 3GPP TS 36.300 V14.1.0 (2016-12);Figure 2 shows a diagram illustrating an example of a User Equipment (UE) in partially overlapping cells;Figure 3a shows a PDCP PDU Structure;Figure 3b shows a RLC PDU Structure;Figure 4 shows a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention; andFigures 5a and 5b each show a method that can be performed by an apparatus in accordance with the example embodiments of the invention. DETAILED DESCRIPTION: In this invention, we propose novel operations that will improve radio link control and radio link failure operations when duplication at a PDCP sublayer takes place. Figure 1 shows Figure 4.9.3.1-1 of 3GPP TS 36.300 V14.1.0 (2016-12) which shows a C-plane connectivity of eNBs involved in DC for a certain UE. As shown in Figure 1 there is an S1-MME interface terminated at the MeNB and the MeNB and the SeNB are interconnected via X2-C. The S1 interface supports a many-to-many relationship between MME/S-GW and eNBs. For a "split bearer" the Master eNB (MeNB) can be U-plane connected to the MME/S-GW via S1-U and in addition, the MeNB is interconnected to a Secondary eNB (SeNB) via X2-U. The routing function in the PDCP layer of the MeNB decides whether a PDCP layer PDU of a split bearer is sent directly over the local air interface to the UE or whether it is f