RACH transmission using multiple ports

Patent metadata

Field	Value
Publication number	US-10693605-B2
Application number	US-201715690820-A
Country	US
Kind code	B2
Filing date	Aug 30, 2017
Priority date	Sep 30, 2016
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A RACH preamble is transmitted from a UE using multiple antenna ports. A UE splits a data stream containing a RACH preamble into multiple streams corresponding to a same number of antenna ports of the UE. The UE multiplexes the copies of the RACH preamble according to a multiplexing scheme that enables a receiving eNB to discern the different channels used to transmit the signal from the different antenna ports. A RACH procedure is further accomplished in two steps instead of four by the UE then splitting a RACH payload to the same number of streams and multiplexing the RACH payload for transmission to the eNB. The eNB receives both transmissions, and may use the RACH preamble as a reference signal, and responds with a combined message with control information, random access response, and contention resolution information.

First claim

What is claimed is:

1. A method, comprising:
receiving, by a first wireless communications device, one or more synchronization signals on a plurality of beams from a second wireless communications device;
providing, by the first wireless communications device, a random access channel (RACH) preamble to a first antenna port of the first wireless communications device and to a second antenna port of the first wireless communications device for transmission to the second wireless communications device;
providing, by the first wireless communications device, a RACH payload to the first antenna port and the second antenna port for transmission to the second wireless communications device;
transmitting, by the first wireless communications device, the RACH preamble provided to the first and second antenna ports to the second wireless communications device without the RACH payload; and
transmitting, by the first wireless communications device, the RACH payload provided to the first and second antenna ports to the second wireless communications device without the RACH preamble,
wherein the RACH preamble and the RACH payload are beamformed for the transmitting based on one or more beams from among the plurality of beams on which the one or more synchronization signals were received.

2. The method of claim 1 , wherein the transmitting comprises transmitting, by the first wireless communications device, the RACH payload as provided to the first and second antenna ports to the second wireless communications device after transmitting the RACH preamble as provided to the first and second antenna ports as part of a two-step RACH procedure.

3. The method of claim 2 , further comprising:
receiving, by the first wireless communications device from the second wireless communications device, a message comprising control information, a random access response, and a connection resolution message, the message being in response to both the RACH preamble and the RACH payload and as part of the two-step RACH procedure.

4. The method of claim 2 , further comprising:
providing, by the first wireless communications device, the RACH preamble as a reference signal to the second wireless communications device for use with the RACH payload.

5. The method of claim 2 , further comprising:
determining, by the first wireless communications device, the one or more beams associated with a direction having a highest signal quality corresponding to the synchronization signals received from the second wireless communications device;
using, by the first wireless communications device, a first symbol from among a plurality of symbols associated with the one or more beams for transmitting the RACH preamble; and
using, by the first wireless communications device, a second symbol from among the plurality of symbols associated with the one or more beams for transmitting the RACH payload.

6. The method of claim 1 , further comprising:
precoding, by the first wireless communications device, the RACH preamble into a first frequency tone for transmission from a first physical antenna port and a second frequency tone for transmission from a second physical antenna port, the first and second frequency tones being non-overlapping to each other.

7. The method of claim 1 , further comprising:
spreading, by the first wireless communications device before the transmitting the RACH preamble, each component of the RACH preamble into two or more tones at both the first and second antenna ports.

8. The method of claim 1 , further comprising:
determining, by the first wireless communications device, a receive power delta between the first and second antenna ports during reception of a signal from the second wireless communications device;
determining, by the first wireless communications device, a split configuration between the first and second antenna ports using the receive power delta; and
splitting, by the first wireless communications device, a transmit power for the first wireless communications device between the first and second antenna ports according to the split configuration.

9. A method, comprising:
transmitting, by a first wireless communications device, one or more synchronization signals on a plurality of beams to a second wireless communications device;
receiving, at the first wireless communications device, a random access channel (RACH) preamble from the second wireless communications device, the RACH preamble having been conveyed through first and second antenna ports;
receiving, at the first wireless communications device, a RACH payload from the second wireless communications device, the RACH payload having been conveyed through the first and second antenna ports, the RACH preamble and the RACH payload having been beamformed based on one or more beams from among the plurality of beams on which the one or more synchronization signals were transmitted;
recovering, by the first wireless communications device, first and second data streams corresponding to the first and second antenna ports for the RACH preamble, and third and fourth data streams corresponding to the first and second antenna ports for the RACH payload; and
determining, by the first wireless communications device, an identity of the second wireless communications device based on the receiving the RACH preamble through the first and second antenna ports and the recovering the first and second data streams.

10. The method of claim 9 , further comprising:
receiving, by the first wireless communications device, the RACH preamble prior to receiving the RACH payload as part of a two-step RACH procedure; and
determining, by the first wireless communications device, a response message based on the recovering the third and fourth data streams.

11. The method of claim 10 , further comprising:
estimating, by the first wireless communications device, a channel between the first and second wireless communications devices based on the RACH preamble functioning as a reference signal.

12. The method of claim 10 , further comprising:
transmitting, by the first wireless communications device in response to both the RACH preamble and the RACH payload and as part of the two-step RACH procedure, the response message to the second wireless communications device, the response message comprising control information, a random access response, and a connection resolution message.

13. The method of claim 10 ,
wherein the RACH preamble is included with a first symbol from among a plurality of symbols associated with the one or more beams, and the RACH payload is included with a second symbol from among the plurality of symbols associated with the one or more beams.

14. The method of claim 9 , wherein the recovering further comprises:
decoding, by the first wireless communications device, the RACH preamble from a first frequency tone and a second frequency tone that are non-overlapping to each other.

15. The method of claim 9 , wherein the recovering further comprises:
despreading, by the first wireless communications device, each component of the RACH preamble from two or more tones from both the first and second antenna ports.

16. The method of claim 9 , further comprising:
detecting, by the first wireless communications device, a transmit power of the received RACH preamble as split between the first and second antenna ports, wherein the transmit power is based on a power of a prior signal from the first wireless communications device as received at the second wireless communications device.

17. An apparatus, comprising:
first and second

Assignees

• Qualcomm Inc

Inventors

• Islam Muhammad Nazmul
• Abedini Navid
• Sadiq Bilal
• Subramanian Sundar
• Li Junyi

Classifications

• H04W72/30

  Resource management for broadcast services · CPC title

• H04W74/0833 Primary

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

• H04W74/0836

  with 2-step access · CPC title

• H04W74/0838

  using contention-free random access [CFRA] · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title