US 11,950,146 B2
PDCP and ROHC handling for multi-connectivity handover
Candy Yiu, Portland, OR (US); Yujian Zhang, Beijing (CN); Yi Guo, Shanghai (CN); and Jaemin Han, Portland, OR (US)
Assigned to Apple Inc., Cupertino, CA (US)
Appl. No. 17/274,311
Filed by Apple Inc., Cupertino, CA (US)
PCT Filed Sep. 23, 2019, PCT No. PCT/US2019/052412
§ 371(c)(1), (2) Date Mar. 8, 2021,
PCT Pub. No. WO2020/068659, PCT Pub. Date Apr. 2, 2020.
Claims priority of provisional application 62/737,683, filed on Sep. 27, 2018.
Prior Publication US 2022/0053389 A1, Feb. 17, 2022
Int. Cl. H04W 36/00 (2009.01); H04W 12/037 (2021.01); H04W 12/0431 (2021.01); H04W 28/06 (2009.01); H04W 76/30 (2018.01)
CPC H04W 36/0069 (2018.08) [H04W 12/037 (2021.01); H04W 12/0431 (2021.01); H04W 28/06 (2013.01); H04W 36/0058 (2018.08); H04W 36/00837 (2018.08); H04W 76/30 (2018.02)] 14 Claims
OG exemplary drawing
 
1. An apparatus, comprising:
a processor configured to cause a user equipment device (UE) to, in association with a multi-connectivity handover with a source base station (SBS) and a target base station (TBS):
transmit a measurement report to the SBS, the measurement report triggered based on a measurement event configured by the SBS;
receive radio resource control (RRC) signaling from the SBS, the RRC signaling including a handover command, the handover command including an indication for multi-connectivity support during handover by the SBS and the TBS;
configure a first protocol stack associated with the SBS and a second protocol stack associated with the TBS;
process a packet data convergence protocol (PDCP) protocol data unit (PDU) received at the UE during the handover, using the first protocol stack or the second protocol stack;
determine a sequence number (SN) of the PDCP PDU received at the UE during the handover;
perform integrity and deciphering operations of the PDCP PDU to generate a deciphered PDCP PDU using a first set of security keys associated with the SBS or a second set of security keys associated with the TBS based on whether the PDCP PDU is received from the SBS or the TBS;
store the deciphered PDCP PDU in a common buffer shared between the first protocol stack and the second protocol stack;
perform reordering to associate the deciphered PDCP PDU with the first protocol stack or the second protocol stack, based on the determined SN; and
perform robust header compression (ROHC) decompression of the deciphered PDCP PDU, subsequent to the reordering.