Access procedures for wireless communications
Wireless communications are described for access procedures. A wireless device may use a plurality of identifiers to monitor for a response from a base station. The wireless device may determine whether a random access procedure is a success or a failure based on the identifier that the wireless device is able to use to receive the response.
1. A method comprising:
causing, by a wireless device, transmission of:
a preamble; and
a cell-radio network temporary identifier (C-RNTI);
monitoring for a random access response to the transmission, wherein:
a received random access response that is scheduled by received downlink control information (DCI) identified by a radio network temporary identifier (RNTI) associated with a two-step random access procedure and that comprises an identifier of a preamble indicates proceeding with a transmission associated with a contention resolution procedure; and
received DCI that is identified by the C-RNTI indicates successful completion of a two-step random access procedure; and
based on receiving a random access response that is scheduled by received DCI identified by the RNTI associated with a two-step random access procedure and that comprises the identifier of the preamble, causing transmission of a contention resolution identifier parameter.
2. The method of claim 1 , further comprising receiving a random access response, wherein the monitoring for the random access response comprises monitoring for the random access response based on the RNTI and the C-RNTI.
3. The method of claim 1 , wherein the causing transmission of the contention resolution identifier parameter is further based on the random access response not comprising the contention resolution identifier parameter.
4. The method of claim 1 , wherein the causing transmission of the contention resolution identifier parameter comprises causing a Msg3 transmission that comprises the contention resolution identifier parameter.
5. The method of claim 1 , wherein the transmission of the preamble and the C-RNTI comprises a Msg A transmission.
6. The method of claim 1 , wherein the received DCI that is identified by the C-RNTI consists of at least one of each of:
a timing advance command;
an uplink grant;
a temporary C-RNTI; and
a reserve bit.
7. The method of claim 1 , further comprising:
determining, based on the received DCI that is identified by the RNTI, to fall back from a two-step random access procedure to a four-step random access procedure, wherein the causing transmission of the contention resolution identifier parameter is associated with the four-step random access procedure.
8. The method of claim 1 , further comprising:
causing, by the wireless device, second transmission of:
a preamble; and
the C-RNTI;
monitoring for a response to the second transmission; and
determining, based on receiving a response to the second transmission that is identified by the C-RNTI, successful completion of a two-step random access procedure.
9. The method of claim 1 , further comprising:
starting, based on causing transmission of the preamble and the C-RNTI, a random access response time window; and
stopping, based on received DCI that is identified by the RNTI associated with the random access response, the random access response time window.
10. The method of claim 1 , further comprising:
stopping the monitoring of the random access response based on received DCI that is identified by the C-RNTI; or
stopping the monitoring of the random access response based on received DCI that is identified by the RNTI.
11. The method of claim 1 , wherein the RNTI associated with the random access response is different from an RNTI associated with a four-step random access response.
12. A method comprising:
causing, by a wireless device, transmission of:
a preamble; and
a cell-radio network temporary identifier (C-RNTI), wherein the transmission of the preamble and the C-RNTI comprises a Msg A transmission;
monitoring for a random access response to the transmission, wherein:
a received random access response that is scheduled by received downlink control information (DCI) identified by a radio network temporary identifier (RNTI) associated with a two-step random access procedure and that comprises an identifier of the preamble indicates proceeding with a transmission associated with a contention resolution procedure; and
received DCI that is identified by the C-RNTI indicates successful completion of a two-step random access procedure; and
sending data using an uplink grant in the received DCI that is identified by the C-RNTI.
13. The method of claim 12 , further comprising receiving a random access response, wherein the monitoring for the random access response comprises monitoring for the random access response based on the RNTI and the C-RNTI.
14. The method of claim 12 , further comprising determining, based on the received DCI that is identified by the C-RNTI, the successful completion of the two-step random access procedure.
15. The method of claim 12 , wherein the received DCI that is identified by the RNTI is associated with a Msg B reception.
16. The method of claim 12 , wherein the received DCI that is identified by the C-RNTI consists of at least one of each of:
a timing advance command;
an uplink grant;
a temporary C-RNTI; and
a reserve bit.
17. The method of claim 12 , further comprising:
starting, based on causing the transmission of the preamble and the C-RNTI, a random access response time window; and
stopping, based on the received DCI that is identified by the C-RNTI, the random access response time window.
18. The method of claim 12 , further comprising:
stopping the monitoring of the random access response based on the received DCI that is identified by the C-RNTI; or
stopping the monitoring of the random access response based on received DCI that is identified by the RNTI.
19. A method comprising:
causing, by a wireless device, transmission of:
a preamble; and
a cell-radio network temporary identifier (C-RNTI);
monitoring for a random access response to the transmission based on a radio network temporary identifier (RNTI) and the C-RNTI; and
based on receiving a random access response that is scheduled by received downlink control information (DCI) being identified by the RNTI associated with a two-step random access procedure and that comprises an identifier of the preamble, causing transmission of a contention resolution identifier parameter, wherein the two-step random access procedure is not successfully completed based on the received DCI not being identified by the C-RNTI.
20. The method of claim 19 , further comprising receiving the random access response.
21. The method of claim 19 , wherein the causing transmission of the contention resolution identifier parameter comprises causing a Msg3 transmission that comprises the contention resolution identifier parameter.
22. The method of claim 19 , further comprising:
determining, based on the received DCI, to fall back from the two-step random access procedure to a four-step random access procedure, wherein the causing transmission of the contention resolution identifier parameter is associated with the four-step random access procedure.
23. The method of claim 19 , further comprising:
determining, based on the monitoring for the random access response, that the two-step random access procedure is not successfully completed.
24. The method of claim 19 , wherein the transmission of the preamble and the C-RNTI comprises a Msg A transmission, and wherein the received DCI is associated with a Msg B reception.
25. The method of claim 19 , further comprising:
starting, based on causing the transmission of the preamble and the C-RNTI, a random access response time window; and
stopping, based on the received DCI that is identified by the RNTI associated with the two-step random access procedure, the random access response time window.
26. The method of claim 19 , further comprising:
stopping the monitoring of the random access response based on received DCI that is identified by the C-RNTI; or
stopping the monitoring of the random access response based on the received DCI that is identified by the RNTI.