Ultra-reliable low-latency communications support using grant free transmissions
A user equipment (UE) selects first and second radio resources from respective first and second pools of radio resources. In one example these are primarily allocated for contention-free and scheduling-based channel access, respectively. Content to duplicate in parallel communications is selected based at least on a characteristic of uplink data waiting to be sent (such as size) and/or on the selected first and second radio resources (such as timing difference between them). The UE transmits the selected content on each of the selected first and second radio resources. In the examples the content to duplicate was selected from among the uplink data to send and a scheduling request message. In various embodiments one of these transmissions indicates it's a duplicate, and the duplicated scheduling request message is transmitted on the first resource with the uplink data. These teachings are particularly useful for URLLC data.
1. A method comprising:
selecting for a user equipment a first radio resource from a first pool of radio resources;
selecting a second radio resource from a second pool of radio resources;
selecting which content to duplicate on parallel communications based on at least one of a size of uplink data waiting to be sent, a timing difference between the selected first radio resource and second radio resource, or a latency and a reliability requirement of the uplink data waiting to be sent,
wherein, when based on the size of uplink data waiting to be sent, the selecting which content to duplicate comprises at least one of:
content of a scheduling request message is selected as the content to duplicate based on the size of the uplink data waiting to be sent is larger than can be accommodated by a transport block of the selected first radio resource from the first pool of radio resources, or
content of the uplink data is selected as the content to duplicate based on the size of the uplink data waiting to be sent can be accommodated by a transport block of the selected second radio resource from the second pool of radio resources,
wherein one of:
the selecting the scheduling request message and the uplink data is in response to a failed attempt to send the scheduling request on another radio resource from the first pool in parallel with the uplink data being sent on another radio resource from the second pool;
or
the scheduling request is sent on another radio resource from the first pool in parallel with the uplink data being sent on another radio resource from the second pool in response to receiving a negative acknowledgement to the transmitting, and
wherein the selected content to duplicate comprises content from at least the scheduling request message for the user equipment and the uplink data; and
transmitting the selected content on each of the selected first radio resource and the selected second radio resource.
2. The method according to claim 1 , wherein:
the transmitting comprises:
transmitting on the selected second radio resource the scheduling request message; and
transmitting on the selected first radio resource the scheduling request message and a portion of the uplink data, where the scheduling request message transmitted on the selected first radio resource comprises an indication of a total number of consecutive radio resources from the first pool to be expected.
3. The method according to claim 1 , wherein:
on only one of the selected first radio resource or the selected second radio resource the selected content is transmitted with an indication that the content is a duplicate.
4. The method according to claim 1 , wherein the scheduling request message or the uplink data transmitted on each of the selected first radio resource and second radio resource further indicates if the respectively transmitted content is a first transmission or a re-transmission.
5. The method according to claim 1 , wherein the selected content is the scheduling request message and is transmitted with a buffer status report indicating a length of the uplink data to be sent.
6. The method according to claim 1 , wherein:
multiple radio resources are selected from the second pool of radio resources; and
the selected content is transmitted on the selected first radio resource and on the multiple radio resources selected from the second pool of radio resources.
7. The method according to claim 1 , wherein the transmitting the selected content on each of the selected first radio resource and the selected second radio resource is for grant-free uplink transmissions of data.
8. The method according to claim 1 , wherein:
the first pool of radio resources is primarily allocated for contention-based channel access; and
the second pool of radio resources is primarily allocated for scheduling-based channel access.
9. An apparatus comprising:
at least one non-transitory memory storing instructions; and
at least one processor;
wherein the at least one non-transitory memory storing instructions is executed by the at least one processor to cause the apparatus to:
select for a user equipment a first radio resource from a first pool of radio resources;
select a second radio resource from a second pool of radio resources;
select which content to duplicate in parallel communications based on at least one of a size of uplink data waiting to be sent, a timing difference between the selected first radio resource and second radio resource, or a latency and a reliability requirement of the uplink data waiting to be sent,
wherein, when based on the size of uplink data waiting to be sent, the selecting which content to duplicate comprises at least one of:
content of a scheduling request message is selected as the content to duplicate based on the size of the uplink data waiting to be sent is larger than can be accommodated by a transport block of the selected first radio resource from the first pool of radio resources, or
content of the uplink data is selected as the content to duplicate based on the size of the uplink data waiting to be sent can be accommodated by a transport block of the selected second radio resource from the second pool of radio resources,
wherein one of:
the selecting the scheduling request message and the uplink data is in response to a failed attempt to send the scheduling request on another radio resource from the first pool in parallel with the uplink data being sent on another radio resource from the second pool;
or
the scheduling request is sent on another radio resource from the first pool in parallel with the uplink data being sent on another radio resource from the second pool in response to receiving a negative acknowledgement to the transmitting, and
wherein the selected content to duplicate comprises content from at least the scheduling request message for the user equipment and the uplink data; and
transmit the selected content on each of the selected first radio resource and the selected second radio resource.
10. The apparatus according to claim 9 , wherein:
the first pool is primarily allocated for contention-based channel access.
11. The apparatus according to claim 9 , wherein:
the scheduling request message is transmitted on the selected second radio resource; and
the scheduling request message and a portion of the uplink data are transmitted on the selected first radio resource, where the scheduling request message transmitted on the selected first radio resource comprises an indication of a total number of consecutive radio resources from the first pool to be expected.
12. The apparatus according to claim 9 , wherein:
on only one of the selected first radio resource or the selected second radio resource the selected content is transmitted with an indication that the content is a duplicate.
13. The apparatus according to claim 9 , wherein at least one of:
the scheduling request message or the uplink data transmitted on each of the selected first and second radio resources further indicates if the respectively transmitted content is a first transmission or a re-transmission; and
the selected content is the scheduling request message and is transmitted with a buffer status report indicating a length of the uplink data to be sent.
14. The apparatus according to claim 9 , wherein selecting which content to duplicate is based on at least one of:
size of the uplink data waiting to be sent;
a timing difference between the selected first and second radio resources;
a latency requirement of the uplink data waiting to be sent; and
a reliability requirement of the uplink data waiting to be sent.
15. A non-transitory memory storing instructions that, when executed by one or more processors, cause an apparatus to perform actions comprising:
selecting, by a user equipment, a first radio resource from a first pool of radio resources;
selecting a second radio resource from a second pool of radio resources;
selecting which content to duplicate in parallel communications based on at least one of a size of uplink data waiting to be sent, a timing difference between the selected first radio resource and second radio resource, or a latency and a reliability requirement of the uplink data waiting to be sent,
wherein one of:
the selecting the content to duplicate is in response to a failed attempt to send the scheduling request on another radio resource from the first pool in parallel with the uplink data being sent on another radio resource from the second pool;
or
the scheduling request is sent on another radio resource from the first pool in parallel with the uplink data being sent on another radio resource from the second pool in response to receiving a negative acknowledgement to the transmitting, and
wherein, when based on the size of uplink data waiting to be sent, the selecting comprises at least one of:
content of a scheduling request message is selected as the content to duplicate based on the size of the uplink data waiting to be sent is larger than can be accommodated by a transport block of the selected first radio resource from the first pool of radio resources, or
content of the uplink data is selected as the content to duplicate based on the size of the uplink data waiting to be sent can be accommodated by a transport block of the selected second radio resource from the second pool of radio resources, and
wherein the selected content to duplicate comprises content from at least Raphe scheduling request message for the user equipment and the uplink data; and
transmitting the selected content on each of the selected first radio resource and the selected second radio resource.
16. The non-transitory memory according to claim 15 , wherein the second pool is primarily allocated for scheduling-based channel access.
17. The non-transitory memory according to claim 15 , wherein the transmitting comprises;
transmitting on the selected second radio resource the scheduling request message; and
transmitting on the selected first radio resource the scheduling request message and a portion of the uplink data, where the scheduling request message transmitted on the selected first radio resource comprises an indication of a total number of consecutive radio resources from the first pool to be expected.
18. The non-transitory memory according to claim 15 , wherein selecting which content to duplicate is based on at least one of:
a timing difference between the selected first and second radio resources;
a latency requirement of the uplink data waiting to be sent; and
a reliability requirement of the uplink data waiting to be sent.