Method and apparatus for rach procedure in wireless systems

Patent metadata

Field	Value
Publication number	US-2018167979-A1
Application number	US-201715826421-A
Country	US
Kind code	A1
Filing date	Nov 29, 2017
Priority date	Dec 9, 2016
Publication date	Jun 14, 2018
Grant date	—

Abstract

A method of user equipment (UE) for random access operation in a wireless communication system is provided. The method comprises receiving, from a base station (BS), random access channel (RACH) configuration information including RACH chunk information corresponding to at least one antenna beam including a beam identifier (ID), determining a RACH chunk based on the RACH configuration information received from the BS, transmitting, to the BS, a RACH preamble on the determined RACH chunk according to the RACH configuration information associated with the beam ID, and receiving, from the BS, a RACH response (RAR) corresponding to the transmitted RACH preamble and a downlink channel for a RAR transmission, wherein a random access-radio network temporary identification (RA-RNTI) is calculated based on an index of a slot and an index of the RACH chunk on which the RACH preamble is transmitted.

First claim

What is claimed is:

1 . A user equipment (UE) for random access operation in a wireless communication system, the UE comprising:
at least one transceiver configured to:
receive, from a base station (BS), random access channel (RACH) configuration information including RACH chunk information corresponding to at least one antenna beam including a beam identifier (ID); and
at least one processor configured to:
determine a RACH chunk based on the RACH configuration information received from the BS,
wherein the transceiver is further configured to:
transmit, to the BS, a RACH preamble on the determined RACH chunk according to the RACH configuration information associated with the beam ID; and
receive, from the BS, a RACH response (RAR) corresponding to the transmitted RACH preamble and a downlink channel for a RAR transmission, wherein a random access radio network temporary identification (RA-RNTI) is calculated based on an index of a slot and an index of the RACH chunk on which the RACH preamble is transmitted.

2 . The UE of claim 1 , wherein the at least one processor is further configured to determine a RACH occasion for the RACH preamble by:
re-selecting other RACH chunks each of which includes RACH symbols based on the RACH chunk information; or performing a power ramping that adjusts a transmit power of the RACH preamble.

3 . The UE of claim 1 , wherein the RACH configuration information comprises at least one of the index of the slot, the index of the RACH chunk, partitioning information, beam sweeping information, a preamble type, or retransmission information.

4 . The UE of claim 1 , wherein:
the at least one processor is further configured to identify dedicated resources for the BS to apply the at least one antenna beam; and the transceiver is further configured to transmit the RACH preamble on dedicated resources over which the at least one antenna beam is applied to receive signals.

5 . The UE of claim 1 , wherein the transceiver is further configured to transmit the RACH preamble over RACH symbols in the determined RACH chunk over the at least one antenna beam that is swept to receive signals.

6 . The UE of claim 1 , wherein:
the at least one processor is further configured to map, based on the RACH configuration information, downlink signal symbols to RACH chunks, the downlink signal symbols transmitted on at least one of synchronization signal (SS), a broadcasting signal on a physical broadcasting channel (PBCH), or a beam reference signal (BRS); and the transceiver is further configured to transmit the RACH preamble including the beam ID using the RACH chunk from the RACH chunks mapped to at least one downlink signal symbol selected.

7 . The UE of claim 1 , wherein:
the at least one processor is further configured to map, based on the RACH configuration information, downlink signal symbols to a subset of RACH preamble sequences, the downlink signal symbols being conveyed by at least one of synchronization signal (SS), a broadcasting signal on a physical broadcasting channel (PBCH), or a beam reference signal (BRS); and the transceiver is further configured to transmit the RACH preamble including the beam ID using a RACH preamble sequence from the subset of RACH preamble sequences mapped to at least one downlink signal symbol selected.

8 . A base station (BS) for random access operation in a wireless communication system, the BS comprising:
at least one processor configured to:
determine random access channel (RACH) configuration information including a RACH chunk;
at least one transceiver configured to:
transmit, to a user equipment (UE), the RACH configuration information including RACH chunk information corresponding to at least one antenna beam including a beam identifier (ID);
receive, from the UE, a RACH preamble on the RACH chunk according to the RACH configuration information associated with the beam ID; and
transmit, to the UE, a RACH response (RAR) corresponding to the received RACH preamble and a downlink channel for a RAR transmission, wherein a random access-radio network temporary identification (RA-RNTI) is calculated based on an index of a slot and an index of the RACH chunk on which the RACH preamble is received.

9 . The BS of claim 8 , wherein the transceiver is further configured to receive the RACH preamble based on a RACH occasion by:
re-selecting, by the UE, other RACH chunks each of which includes RACH symbols based on the RACH chunk information; or performing, by the UE, a power ramping that adjusts a transmit power of the RACH preamble.

10 . The BS of claim 8 , wherein the RACH configuration information comprises at least one of the index of the slot, the index of the RACH chunk, partitioning information, beam sweeping information, a preamble type, or retransmission information.

11 . The BS of claim 8 , wherein the transceiver is further configured to receive the RACH preamble on dedicated resources over which the at least one antenna beam is applied to receive signals, the dedicated resources being identified based on the at least one antenna beam.

12 . The BS of claim 8 , wherein the transceiver is further configured to receive the RACH preamble over RACH symbols in the determined RACH chunk over the at least one antenna beam that is swept to receive signals.

13 . The BS of claim 8 , wherein:
the at least one processor is further configured to map, based on the RACH configuration information, downlink signal symbols to RACH chunks, the downlink signal symbols transmitted on at least one of synchronization signal (SS), a broadcasting signal on a physical broadcasting channel (PBCH), or a beam reference signal (BRS); and the transceiver is further configured to receive the RACH preamble including the beam ID using the RACH chunk from the RACH chunks mapped to at least one downlink signal symbol selected.

14 . The BS of claim 8 , wherein:
the at least one processor is further configured to map, based on the RACH configuration information, downlink signal symbols to a subset of RACH preamble sequences, the downlink signal symbols being conveyed by at least one of synchronization signal (SS), a broadcasting signal on a physical broadcasting channel (PBCH), or a beam reference signal (BRS); and the transceiver is further configured to receive the RACH preamble including the beam ID using a RACH preamble sequence from the subset of RACH preamble sequences mapped to at least one downlink signal symbol selected.

15 . A method of user equipment (UE) for random access operation in a wireless communication system, the method comprising:
receiving, from a base station (BS), random access channel (RACH) configuration information including RACH chunk information corresponding to at least one antenna beam including a beam identifier (ID); determining a RACH chunk based on the RACH configuration information received from the BS, transmitting, to the BS, a RACH preamble on the determined RACH chunk according to the RACH configuration information associated with the beam ID; and receiving, from the BS, a RACH response (RAR) corresponding to the transmitted RACH preamble and a downlink channel for a RAR transmission, wherein a random access-radio network temporary identification (RA-RNTI) is calculated based on an index of a slot and an index of the RACH chunk on which the RACH preamble is transmitted.

16 . The method of claim 15 , further comprising determining a RACH occasion for the RACH preamble by:
re-selecting other RACH chunks each of which includes RACH symbols based on the RACH chunk informati

Assignees

• Samsung Electronics Co Ltd

Inventors

• Guo Li
• Nam Young-Han
• Ng Boon Loong

Classifications

• H04W74/0833 Primary

  Random access procedures, e.g. with 4-step access · CPC title

• H04W72/0453

  Resources in frequency domain, e.g. a carrier in FDMA · CPC title

• H04W16/28

  using beam steering · CPC title

• H04W74/004

  in the uplink, i.e. towards network · CPC title

• H04W74/006 Primary

  in the downlink, i.e. towards the terminal · CPC title