TECHNIQUES FOR ACCESSING A CELL USING AN UNLICENSED RADIO FREQUENCY SPECTRUM BAND

• US 20160095018A1
• Filed: 09/25/2015
• Published: 03/31/2016
• Est. Priority Date: 09/29/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Vajapeyam, Madhavan Srinivasan, Damnjanovic, Aleksandar, Malladi, Durga Prasad, Wei, Yongbin
• Granted Patent: US 11,343,680 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 28/0278 using buffer status reports dynamic wireless traffic scheduling definition H04W72/12
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 76/19 Connection re-establishment

Abstract

Techniques are described for wireless communication. One method includes winning a contention for access to an unlicensed radio frequency spectrum band, transmitting a request message upon winning the contention for access to the unlicensed radio frequency spectrum band, and receiving a response message over the unlicensed radio frequency spectrum band. The request message is transmitted by a user equipment (UE) on an enhanced physical random access channel (ePRACH), to access a cell that operates in the unlicensed radio frequency spectrum band. The response message is received in response to transmitting the request message.

Claims

1. A method for wireless communication, comprising:

winning a contention for access to an unlicensed radio frequency spectrum band;

transmitting a request message upon winning the contention for access to the unlicensed radio frequency spectrum band, the request message transmitted by a user equipment (UE) on an enhanced physical random access channel (ePRACH), to access a cell that operates in the unlicensed radio frequency spectrum band; and

receiving, in response to transmitting the request message, a response message over the unlicensed radio frequency spectrum band.

2. The method of claim 1, wherein the request message comprises at least one of:

a connection setup request;

a handover completion indication;

a connection reestablishment request;

a buffer status report;

a device identifier;

or a cause value.

3. The method of claim 1, wherein the response message comprises at least one of:

a connection configuration message;

a channel contention resolution indication;

a scheduled uplink grant;

a device identifier;

or an indication of a timing adjustment.

4. The method of claim 1, wherein the ePRACH is transmitted over the unlicensed radio frequency spectrum band.

5. The method of claim 1, wherein the request message is an unscheduled request message.

6. The method of claim 1, further comprising:

receiving, in a system information block, an indication of at least one time window for reception of the response message.

7. The method of claim 6, further comprising:

monitoring the unlicensed radio frequency spectrum band for the response message during at least one of the at least one time window.

8. The method of claim 6, wherein the indication of the at least one time window comprises a first indication of at least one connection establishment time window and a second indication of at least one handover time window.

9. The method of claim 1, further comprising:

receiving, in a system information block, a mapping of resource sets of the ePRACH to frequency-interlaced resource blocks.

10. The method of claim 9, further comprising:

selecting, from among the resource sets of the ePRACH, a resource set for transmitting the request message.

11. The method of claim 9, further comprising:

receiving, in the system information block, at least one indication of a transport block size for the ePRACH.

12. The method of claim 11, further comprising:

receiving, in the system information block, at least one power control parameter for the ePRACH.

13. The method of claim 1, further comprising:

receiving, in a system information block, an indication of at least one subframe available to perform the transmitting.

14. The method of claim 1, further comprising:

transmitting a scheduled confirmation message in response to receiving the response message.

15. The method of claim 1, further comprising:

repeating the transmitting before receiving the response message.

16. The method of claim 1, wherein the ePRACH comprises at least one contention-based resource set.

17. The method of claim 16, wherein the ePRACH further comprises at least one dedicated resource set.

18. The method of claim 16, wherein the request message is a handover completion indication transmitted using one of the at least one dedicated resource set.

19. The method of claim 1, wherein the request message is transmitted in synchronization with a subframe boundary.

20. A method for wireless communication, comprising:

transmitting a request message, the request message transmitted by a user equipment (UE) on an enhanced physical random access channel (ePRACH), without winning a contention for access to an unlicensed radio frequency spectrum band, to access a cell that operates in the unlicensed radio frequency spectrum band; and

receiving, in response to transmitting the request message, a response message over the unlicensed radio frequency spectrum band.

21. The method of claim 20, wherein the request message is transmitted during a preconfigured uplink clear channel assessment (CCA)-exempt transmission (CET) occasion.

22. A method for wireless communication, comprising:

winning a contention for access to an unlicensed radio frequency spectrum band;

receiving a first request message, the first request message received by a base station on an enhanced physical random access channel (ePRACH), from a first user equipment (UE), to access a cell that operates in the unlicensed radio frequency spectrum band; and

transmitting, in response to winning the contention for access to the unlicensed radio frequency spectrum band and in response to receiving the first request message from the first UE, a response message over the unlicensed radio frequency spectrum band.

23. The method of claim 22, wherein the first request message comprises at least one of:

a connection setup request;

a handover completion indication;

a connection establishment request;

a buffer status report;

a device identifier;

or a cause value.

24. The method of claim 22, wherein the response message comprises at least one of:

a connection configuration message;

a channel contention resolution indication;

a scheduled uplink grant;

a device identifier;

or an indication of a timing adjustment.

25. The method of claim 22, wherein the ePRACH is received over the unlicensed radio frequency spectrum band.

26. The method of claim 22, further comprising:

requesting from a source base station, between receiving the first request message and transmitting the response message, a context of the first UE.

27. The method of claim 22, further comprising:

receiving a respective request message from at least one of a plurality of UEs, each respective request message comprising a respective device identifier, wherein the first request message comprises a first device identifier.

28. The method of claim 27, further comprising:

resolving channel contention between the plurality of UEs in favor of the first UE; and

including the first device identifier in the response message.

29. A method for wireless communication, comprising:

receiving a first request message, the first request message received by a base station on an enhanced physical random access channel (ePRACH), from a first user equipment (UE), to access a cell that operates in an unlicensed radio frequency spectrum band; and

transmitting, in response to receiving the first request message from the first UE and without winning a contention for access to the unlicensed radio frequency spectrum band, a response message over the unlicensed radio frequency spectrum band.

30. The method of claim 29, wherein the request message is transmitted during a preconfigured downlink clear channel assessment (CCA)-exempt transmission (CET) occasion.