Retransmission bandwidth reduction
Aspects relate to using a reduced bandwidth for a retransmission of a first transmission, where the bandwidth reduction is based on acknowledgement information associated with the first transmission. For example, the amount of the bandwidth reduction may be based on the number of positive acknowledgements and/or negative acknowledgements sent by a UE in response to the first transmission. In some examples, the reduction in bandwidth may be applicable to a control search space and/or a data resource allocation.
1 . A first apparatus for wireless communication, comprising:
at least one transceiver;
at least one memory configured to store processor executable code; and
at least one processor configured to execute the processor-executable code to cause the first apparatus to:
receive, from a second apparatus via the at least one transceiver, first information indicative of at least one reduction in retransmission bandwidth relative to a first initial transmission bandwidth associated with a physical downlink control channel PDCCH) and a second initial transmission bandwidth, different from the first initial transmission bandwidth, associated with a physical downlink shared channel (PDSCH), the at least one reduction in retransmission bandwidth being associated with acknowledgement information;
receive, via the at least one transceiver and the first initial transmission bandwidth associated with the PDCCH, a first PDCCH transmission from the second apparatus;
receive, via the at least one transceiver and the second initial transmission bandwidth associated with the PDSCH, a first PDSCH transmission from the second apparatus;
transmit, to the second apparatus via the at least one transceiver, first acknowledgement information associated with the first PDSCH transmission, the first acknowledgement information comprising a positive acknowledgement (ACK) or a negative acknowledgement (NACK);
select a first retransmission bandwidth associated with the PDCCH and a second retransmission bandwidth, different from the first retransmission bandwidth, associated with the PDSCH, wherein the first retransmission bandwidth is narrower than the first initial transmission bandwidth and the second retransmission bandwidth is narrower than the second initial transmission bandwidth, the selection of the first retransmission bandwidth and the second retransmission bandwidth being associated with the first information indicative of the at least one reduction in retransmission bandwidth and the first acknowledgement information comprising the ACK or NACK;
monitor, via the at least one transceiver and the first retransmission bandwidth, for a second PDCCH transmission associated with the first PDCCH transmission; and
monitor, via the at least one transceiver and the second retransmission bandwidth, for a second PDSCH transmission associated with retransmission of the first PDSCH transmission.
2 . The first apparatus of claim 1 , wherein at least one of:
the second initial transmission bandwidth is associated with a first physical downlink shared channel resource allocation; or
the second retransmission bandwidth is associated with a second physical downlink shared channel resource allocation.
3 . The first apparatus of claim 1 , wherein at least one of:
the first initial transmission bandwidth is associated with a first physical downlink control channel search space; or
the first retransmission bandwidth is associated with a second physical downlink control channel search space.
4 . The first apparatus of claim 1 , wherein:
the first information maps a first bandwidth reduction to a first NACK/ACK ratio;
the first information maps a second bandwidth reduction to a second NACK/ACK ratio;
the first bandwidth reduction is different from the second bandwidth reduction;
the first NACK/ACK ratio is different from the second NACK/ACK ratio; and
the selection of the first retransmission bandwidth or the second retransmission bandwidth comprises a selection of the first bandwidth reduction based on a comparison of the first acknowledgement information with the first NACK/ACK ratio.
5 . The first apparatus of claim 4 , wherein at least one of:
the first bandwidth reduction is associated with at least one of: a first physical downlink shared channel resource allocation, or a first physical downlink control channel search space; or
the second bandwidth reduction is associated with at least one of: a second physical downlink shared channel resource allocation, or a second physical downlink control channel search space.
6 . The first apparatus of claim 4 , wherein:
the first bandwidth reduction indicates a first percentage of the first initial transmission bandwidth;
the second bandwidth reduction indicates a second percentage of the first initial transmission bandwidth; and
the first percentage is different from the second percentage.
7 . The first apparatus of claim 1 , wherein the first acknowledgement information indicates a NACK/ACK ratio associated with the first PDSCH transmission.
8 . The first apparatus of claim 1 , wherein the first information indicates a location of the first retransmission bandwidth within the first initial transmission bandwidth.
9 . The first apparatus of claim 1 , wherein the first information indicates a frequency offset of the first retransmission bandwidth.
10 . The first apparatus of claim 1 , wherein:
the first information indicates a first slot offset between the first PDSCH transmission and the second PDSCH transmission; or
the first information indicates a second slot offset between the second PDSCH transmission and another retransmission of the first PDSCH transmission.
11 . The first apparatus of claim 1 , wherein the selection of the first retransmission bandwidth comprises an identification, based on the first information, of a first bandwidth reduction that maps to the first acknowledgement information.
12 . The first apparatus of claim 1 , wherein the selection of the first retransmission bandwidth comprises an identification, based on the first information, of a first bandwidth offset that maps to the first acknowledgement information.
13 . The first apparatus of claim 1 , wherein the processing system is further configured to:
identify, based on the first information, a slot offset that maps to the first acknowledgement information.
14 . The first apparatus of claim 1 , wherein the first information is received via downlink control information, a medium access control-control element (MAC-CE), or a radio resource control (RRC) message.
15 . The first apparatus of claim 1 , wherein the first apparatus is configured to operate as a user equipment.
16 . A first apparatus for wireless communication, comprising:
at least one transceiver;
at least one memory configured to store processor executable code; and
at least one processor configured to execute the processor-executable code to cause the first apparatus to:
transmit, to a second apparatus via the at least one transceiver, first information indicative of at least one reduction in retransmission bandwidth relative to a first initial transmission bandwidth associated with a physical downlink control channel (PDCCH) and a second initial transmission bandwidth, different from the first initial transmission bandwidth, associated with a physical downlink shared channel (PDSCH), the at least one reduction in retransmission bandwidth being associated with acknowledgement information;
transmit, to the second apparatus via the at least one transceiver and the first initial transmission bandwidth associated with the PDCCH, a first PDCCH transmission;
transmit, to the second apparatus via the at least one transceiver and the second initial transmission bandwidth associated with the PDSCH, a first PDSCH transmission;
receive, from the second apparatus via the at least one transceiver, first acknowledgement information associated with the first PDSCH transmission, the first acknowledgement information comprising a positive acknowledgement (ACK) or a negative acknowledgement (NACK);
select a first retransmission bandwidth associated with the PDCCH and a second retransmission bandwidth, different from the first retransmission bandwidth, associated with the PDSCH, wherein the first retransmission bandwidth is narrower than the first initial transmission bandwidth and the second retransmission bandwidth is narrower than the second initial transmission bandwidth, the selection of the second-first retransmission bandwidth and the second retransmission bandwidth being associated with the first information indicative of the at least one reduction in retransmission bandwidth and the first acknowledgement information comprising the ACK or NACK;
transmit, via the at least one transceiver and the first retransmission bandwidth, a second PDCCH transmission associated with the first PDCCH transmission; and
transmit, via the at least one transceiver and the second retransmission bandwidth, a second PDSCH transmission associated with retransmission of the first PDSCH transmission.
17 . The first apparatus of claim 16 , wherein at least one of:
the second initial transmission bandwidth is associated with a first physical downlink shared channel resource allocation; or
the second retransmission bandwidth is associated with a second physical downlink shared channel resource allocation.
18 . The first apparatus of claim 16 , wherein at least one of:
the first initial transmission bandwidth is associated with a first physical downlink control channel search space; or
the first retransmission bandwidth is associated with a second physical downlink control channel search space.
19 . The first apparatus of claim 16 , wherein:
the first information maps a first bandwidth reduction to a first NACK/ACK ratio;
the first information maps a second bandwidth reduction to a second NACK/ACK ratio;
the first bandwidth reduction is different from the second bandwidth reduction;
the first NACK/ACK ratio is different from the second NACK/ACK ratio; and
the selection of the first retransmission bandwidth or the second retransmission bandwidth comprises a selection of the first bandwidth reduction based on a comparison of the first acknowledgement information with the first NACK/ACK ratio.
20 . The first apparatus of claim 19 , wherein at least one of:
the first bandwidth reduction is associated with at least one of: a first physical downlink shared channel resource allocation, or a first physical downlink control channel search space; or
the second bandwidth reduction is associated with at least one of: a second physical downlink shared channel resource allocation, or a second physical downlink control channel search space.
21 . The first apparatus of claim 19 , wherein:
the first bandwidth reduction indicates a first percentage of the first initial transmission bandwidth;
the second bandwidth reduction indicates a second percentage of the first initial transmission bandwidth; and
the first percentage is different from the second percentage.
22 . The first apparatus of claim 16 , wherein the first acknowledgement information indicates a NACK/ACK ratio associated with the first PDSCH transmission.
23 . The first apparatus of claim 16 , wherein the first information indicates a location of the first retransmission bandwidth within the first initial transmission bandwidth.
24 . The first apparatus of claim 16 , wherein the first information indicates a frequency offset of the first retransmission bandwidth.
25 . The first apparatus of claim 16 , wherein:
the first information indicates a first slot offset between the first PDSCH transmission and the second PDSCH transmission; or
the first information indicates a second slot offset between the second PDSCH transmission and another retransmission of the first PDSCH transmission.
26 . The first apparatus of claim 16 , wherein the selection of the first retransmission bandwidth comprises an identification, based on the first information, of a first bandwidth reduction that maps to the first acknowledgement information.
27 . The first apparatus of claim 16 , wherein the selection of the first retransmission bandwidth comprises an identification, based on the first information, of a first bandwidth offset that maps to the first acknowledgement information.
28 . The first apparatus of claim 16 , wherein the processing system is further configured to:
include, in the first information, a slot offset that maps to the first acknowledgement information.
29 . The first apparatus of claim 16 , wherein the first information is transmitted via downlink control information, a medium access control-control element (MAC-CE), or a radio resource control (RRC) message.
30 . The first apparatus of claim 16
wherein the first apparatus is configured to operate as a network entity.