Ue capability signaling to support enhancements of a random access operation for 5g new radio (nr) in unlicensed spectrum (nr-u)

Abstract

A method for UE capability signaling to support enhancements of a random access operation for NR-U is proposed. A UE transfers UE capability information to a mobile communication network, and the UE capability information includes information indicating the UE's capability on random access operation in unlicensed spectrum. The UE receives configuration of an unlicensed cell from the mobile communication network. The UE performs a random access operation on the unlicensed cell according to the configuration.

What is claimed is: 
     
         1 . A method, comprising:
 transferring User Equipment (UE) capability information to a mobile communication network by a UE, wherein the UE capability information comprises information indicating the UE's capability on random access operation in unlicensed spectrum;   receiving configuration of an unlicensed cell from the mobile communication network by the UE; and   performing a random access operation on the unlicensed cell according to the configuration by the UE.   
     
     
         2 . The method of  claim 1 , wherein the UE capability information comprises a first indicator of whether the UE supports a Physical Random Access Channel (PRACH) transmission using a single long Zadoff-Chu (ZC) sequence, and the random access operation comprises performing the PRACH transmission using the single long ZC sequence. 
     
     
         3 . The method of  claim 2 , wherein the ZC sequence has a length value of 1151 or 571. 
     
     
         4 . The method of  claim 1 , wherein the configuration comprises a PRACH sequence length being 1151 or 571. 
     
     
         5 . The method of  claim 2 , wherein the unlicensed cell is configured by the mobile communication network as a Secondary Cell (SCell) for a carrier aggregation, or as a Primary SCell (PSCell) for a Dual Connectivity (DC) operation, or as a target cell for a handover. 
     
     
         6 . The method of  claim 1 , wherein the UE capability information comprises a second indicator of whether the UE supports extension of a Random Access Response (RAR) window. 
     
     
         7 . The method of  claim 6 , wherein the extension of the RAR window comprises extending the RAR window from 10 milliseconds to 40 milliseconds. 
     
     
         8 . The method of  claim 6 , wherein the configuration comprises an RAR window greater than 10 milliseconds. 
     
     
         9 . The method of  claim 6 , wherein the random access operation comprises:
 monitoring an RAR from the mobile communication network for at most a duration of the RAR window; and   decoding a 2-bit System Frame Number (SFN) indication in a Downlink Control Information (DCI) scheduling of the RAR.   
     
     
         10 . The method of  claim 1 , wherein the UE's capability on random access operation in unlicensed spectrum is set and reported per frequency band by the UE. 
     
     
         11 . A User Equipment (UE), comprising:
 a transmitter that transfers UE capability information to a mobile communication network, wherein the UE capability information comprises information indicating the UE's capability on random access operation in unlicensed spectrum;   a receiver that receives configuration of an unlicensed cell from the mobile communication network; and   a random access handling circuit that performs a random access operation on the unlicensed cell according to the configuration.   
     
     
         12 . The UE of  claim 11 , wherein the UE capability information comprises a first indicator of whether the UE supports a Physical Random Access Channel (PRACH) transmission using a single long Zadoff-Chu (ZC) sequence, and the random access operation comprises performing the PRACH transmission using the single long ZC sequence. 
     
     
         13 . The UE of  claim 12 , wherein the ZC sequence has a length value of 1151 or 571. 
     
     
         14 . The UE of  claim 11 , wherein the configuration comprises a PRACH sequence length being 1151 or 571. 
     
     
         15 . The UE of  claim 12 , wherein the unlicensed cell is configured by the mobile communication network as a Secondary Cell (SCell) for a carrier aggregation, or as a Primary SCell (PSCell) for a Dual Connectivity (DC) operation, or as a target cell for a handover. 
     
     
         16 . The UE of  claim 11 , wherein the UE capability information comprises a second indicator of whether the UE supports extension of a Random Access Response (RAR) window. 
     
     
         17 . The UE of  claim 16 , wherein the extension of the RAR window comprises extending the RAR window from 10 milliseconds to 40 milliseconds. 
     
     
         18 . The UE of  claim 16 , wherein the configuration comprises an RAR window greater than 10 milliseconds. 
     
     
         19 . The UE of  claim 16 , wherein the random access operation comprises:
 monitoring an RAR from the mobile communication network for at most a duration of the RAR window; and   decoding a 2-bit System Frame Number (SFN) indication in a Downlink Control Information (DCI) scheduling of the RAR.   
     
     
         20 . The UE of  claim 11 , wherein the UE's capability on random access operation in unlicensed spectrum is set and reported per frequency band by the UE.