Apparatus, System, and Method for Preambles for Unlicensed Access

• US 20190313458A1
• Filed: 04/01/2019
• Published: 10/10/2019
• Est. Priority Date: 04/06/2018
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Zeng, Wei, Zhang, Wei, Pu, Tianyan, Sun, Haitong, Kim, Yuchul, Zhang, Dawei
• Granted Patent: US 11,057,939 B2
• Time in Patent Office: Days
• CPC Class Codes: H04J 13/0044 OVSF [orthogonal variable spreading factor]
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Apparatuses, systems, and methods for transmitting a preamble. The UE may transmit a preamble to a base station in a random access channel (RACH). The RACH may be located in unlicensed spectrum. The bandwidth of the preamble may cover a majority of a nominal channel bandwidth of the RACH. The UE may receive a random access response and establish a connection with the base station in response to receiving the random access response.

Claims

1. An apparatus, comprising:

one or more processors, wherein the one or more processors are configured to cause a wireless device to;

transmit a preamble to a base station in a random access channel (RACH), wherein the RACH is comprised in unlicensed spectrum, wherein bandwidth of the preamble comprises a majority of a nominal channel bandwidth of the RACH;

receive a random access response; and

establish a connection with the base station in response to receiving the random access response.

2. The apparatus of claim 1, wherein the preamble is transmitted every M subcarriers of the RACH, wherein M is at least 2.

3. The apparatus of claim 2, wherein the one or more processing elements are further configured to cause the wireless device to:

receive configuration information from the BS prior to transmitting the preamble, wherein the configuration information specifies the value of M.

4. The apparatus of claim 2, wherein the preamble is transmitted over a first plurality of subcarriers, wherein the UE is included in a first RACH group, wherein other UEs of a different RACH group transmit preambles over a second plurality of subcarriers that are different from the first plurality of subcarriers, wherein the second plurality of subcarriers are also every M subcarriers.

5. The apparatus of claim 4, wherein a second UE is configured to transmit a second preamble using the same M subcarriers of the RACH, wherein the UE and the second UE transmit the preamble and the second preamble in a code division multiplexed manner.

6. The apparatus of claim 2, wherein the preamble is transmitted with a same subcarrier spacing as preambles transmitted in licensed spectrum.

7. The apparatus of claim 2, wherein the preamble is interlaced in the frequency domain with reference signals.

8. The apparatus of claim 1, wherein the preamble is transmitted with a larger subcarrier spacing than preambles transmitted in licensed spectrum.

9. The apparatus of claim 8, wherein the one or more processing elements are further configured to cause the wireless device to:

transmit the preamble a plurality of times.

10. The apparatus of claim 8, wherein the preamble is code division multiplexed with preambles of other UEs using the same larger sub-carrier spacing, wherein the code division multiplexing is achieved by applying time domain orthogonal cover codes over the plurality of preamble repetitions.

11. A wireless device, comprising:

an antenna;

a radio coupled to the antenna; and

a processing element coupled to the radio;

wherein the processing element is configured to cause the wireless device to;

transmit a preamble to a base station in a random access channel (RACH), wherein the RACH is located in unlicensed spectrum, wherein bandwidth of the preamble is substantially larger than preambles transmitted to the base station within a RACH in licensed spectrum;

receive a random access response; and

establish a connection with the base station in response to receiving the random access response.

12. The wireless device of claim 11, wherein the preamble is transmitted every M subcarriers of the RACH, wherein M is at least 2.

13. The wireless of claim 12, wherein the one or more processing elements are further configured to cause the wireless device to:

receive configuration information from the BS prior to transmitting the preamble, wherein the configuration information specifies the value of M.

14. The wireless device of claim 12, wherein the processing element is further configured to cause the wireless device to:

transmit a second preamble to the base station in a second RACH located in licensed spectrum, wherein the preamble is transmitted with a same subcarrier spacing as the second preamble.

15. The wireless device of claim 12, wherein the processing element is further configured to cause the wireless device to:

transmit a second preamble to the base station in a second RACH comprised in licensed spectrum, wherein the preamble is transmitted with a larger subcarrier spacing than the second preamble.

16. A method, comprising:

by a user equipment device (UE);

transmitting a preamble to a base station in a random access channel (RACH), wherein the RACH is located in unlicensed spectrum, wherein the bandwidth of the preamble is substantially larger than preambles transmitted in licensed spectrum, wherein the preamble is transmitted substantially at a maximum allowed transmit power based on the bandwidth of the preamble;

receiving a random access response; and

establishing a connection with the base station in response to receiving the random access response.

17. The method of claim 16, wherein the preamble is transmitted every M subcarriers of the RACH, wherein M is at least 2.

18. The method of claim 16, wherein the preamble is transmitted with a same subcarrier spacing as preambles transmitted in licensed spectrum.

19. The method of claim 16, wherein the preamble is transmitted with a larger subcarrier spacing than preambles transmitted in licensed spectrum.

20. The method of claim 19, wherein the sub-carrier spacing is increased by 2Λ

Au relative to the preambles transmitted in the licensed spectrum.