Reception Window Determination for a Random Access Procedure

1 . A method comprising:

receiving, by a wireless device, one or more broadcast messages indicating:

a first time offset used for starting a random access response (RAR) window; and

preamble transmission occasions, wherein each of the preamble transmission occasions is associated with a respective synchronization signal-physical broadcast channel (SS-PBCH) block of SS-PBCH blocks;

determining, for a preamble transmission, a preamble transmission occasion of the preamble transmission occasions, wherein the preamble transmission occasion is associated with an SS-PBCH block selected from the SS-PBCH blocks;

transmitting the preamble transmission via the preamble transmission occasion; and

starting the RAR window from a starting time that is based on:

the preamble transmission occasion;

the first time offset; and

a predefined second time offset.

2 . The method of claim 1 , further comprising transmitting a transport block using an uplink grant indicated by an RAR that the wireless device receives during the RAR window.

3 . The method of claim 1 , wherein the first time offset has a unit of slots.

4 . The method of claim 1 , wherein the predefined second time offset comprises at least one of:

an orthogonal frequency division multiplexing (OFDM) symbol;

a mini-slot;

a slot; or

a subframe.

5 . The method of claim 1 , further comprising selecting, based on a received signal strength of the SS-PBCH block, the SS-PBCH block among the SS-PBCH blocks.

6 . The method of claim 1 , further comprising receiving, during the RAR window, an RAR of the preamble transmission.

7 . The method of claim 1 , wherein the starting time occurs after the preamble transmission occasion with the first time offset and the predefined second time offset.

8 . A method comprising:

transmitting, by a base station, one or more broadcast messages indicating:

a first time offset used for starting a random access response (RAR) window; and

preamble transmission occasions, wherein each of the preamble transmission occasions is associated with a respective synchronization signal-physical broadcast channel (SS-PBCH) block of SS-PBCH blocks;

receiving, from a wireless device, a preamble transmission via a preamble transmission occasion of the preamble transmission occasions; and

transmitting, to the wireless device, an RAR of the preamble transmission during the RAR window that starts from a starting time that is based on:

the preamble transmission occasion;

the first time offset; and

a predefined second time offset.

9 . The method of claim 8 , further comprising receiving a transport block using an uplink grant indicated by an RAR that the base station transmits to the wireless device during the RAR window.

10 . The method of claim 8 , wherein the first time offset has a unit of slots.

11 . The method of claim 8 , wherein the predefined second time offset comprises at least one of:

an orthogonal frequency division multiplexing (OFDM) symbol;

a mini-slot;

a slot; or

a subframe.

12 . The method of claim 8 , further comprising transmitting, during the RAR window, an RAR of the preamble transmission.

13 . The method of claim 8 , wherein the starting time occurs after the preamble transmission occasion with the first time offset and the predefined second time offset.

14 . A wireless device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the wireless device to:

receive one or more broadcast messages indicating:

a first time offset used for starting a random access response (RAR) window; and

preamble transmission occasions, wherein each of the preamble transmission occasions is associated with a respective synchronization signal-physical broadcast channel (SS-PBCH) block of SS-PBCH blocks;

determine, for a preamble transmission, a preamble transmission occasion of the preamble transmission occasions, wherein the preamble transmission occasion is associated with an SS-PBCH block selected from the SS-PBCH blocks;

transmit the preamble transmission via the preamble transmission occasion; and

starting the RAR window from a starting time that is based on:

the preamble transmission occasion;

the first time offset; and

a predefined second time offset.

15 . The wireless device of claim 14 , wherein the instructions further cause the wireless device to transmit a transport block using an uplink grant indicated by an RAR that the wireless device receives during the RAR window.

16 . The wireless device of claim 14 , wherein the first time offset has a unit of slots.

17 . The wireless device of claim 14 , wherein the predefined second time offset comprises at least one of:

an orthogonal frequency division multiplexing (OFDM) symbol;

a mini-slot;

a slot; or

a subframe.

18 . The wireless device of claim 14 , wherein the instructions further cause the wireless device to select, based on a received signal strength of the SS-PBCH block, the SS-PBCH block among the SS-PBCH blocks.

19 . The wireless device of claim 14 , wherein the instructions further cause the wireless device to receive, during the RAR window, an RAR of the preamble transmission.

20 . The wireless device of claim 14 , wherein the starting time occurs after the preamble transmission occasion with the first time offset and the predefined second time offset.