Techniques and apparatuses for downlink channel monitoring
Certain aspects of the present disclosure generally relate to wireless communication. In some aspects, a wireless communication device may receive a plurality of resource blocks of a short channel mapped using a short resource element group (sREG) to short control channel element (sCCE) mapping. The short channel may be a short physical downlink control channel (sPDCCH) or a short physical downlink shared channel (sPDSCH). The wireless communication device may process the short channel using the plurality of resource blocks. The plurality of resource blocks may be bundled into a set of resource block bundles based at least in part on the sREG-to-sCCE mapping.
1. A wireless communication device, comprising:
a memory; and
one or more processors coupled to the memory, the one or more processors configured to:
determine, when transmit diversity is enabled for a channel and when using a short transmission time interval (sTTI) with the channel, a monitoring period for receiving the channel,
wherein the sTTI is associated with a duration that is shorter than a duration of a transmission time interval (TTI) used with another channel, and
wherein the monitoring period is determined based at least in part on a number of resource elements (REs) used for a channel state information reference signal (CSI-RS); and
receive, during the monitoring period, the channel based at least in part on determining the monitoring period for receiving the channel,
wherein the channel is a short physical downlink control channel (sPDCCH) or a short physical downlink shared channel (sPDSCH) and the monitoring period is determined based at least in part on a number of useable tones of the channel being an integer multiple of 2.
2. The wireless communication device of claim 1 , wherein 2-port space frequency block coding (SFBC) is enabled for the channel; and
wherein the one or more processors are configured to determine the monitoring period based at least in part on a configuration of a particular number of configured ports and based at least in part on a 4-port channel state information reference signal (CSI-RS) configuration for the sTTI.
3. The wireless communication device of claim 2 , wherein the channel is the sPDCCH, and wherein the monitoring period omits one or more orphan resource elements (REs) of one or more short resource element groups (sREGs).
4. The wireless communication device of claim 1 , wherein 4-port space frequency block coding (SFBC) is enabled for the channel; and
wherein the one or more processors are configured to determine the monitoring period based at least in part on a configuration of a particular number of configured ports and based at least in part on an 8-port channel state information reference signal (CSI-RS) configuration for the sTTI and based at least in part on the number of useable tones of the channel being an integer multiple of 4.
5. The wireless communication device of claim 4 , wherein the one or more processors are configured to perform rate-matching around one or more resource elements (REs) associated with the 8-port CSI-RS.
6. The wireless communication device of claim 1 , wherein the monitoring period is determined based at least in part on a first one or more modulated symbols in a first short resource element group (sREG) and a second one or more modulated symbols in a second sREG.
7. The wireless communication device of claim 6 , wherein the first sREG and the second sREG are consecutive sREGs with a threshold number of REs and are each associated with the channel.
8. The wireless communication device of claim 1 , wherein the number of useable tones is determined based at least in part on one or more orphan resource elements (REs) being skipped for channel mapping.
9. The wireless communication device of claim 1 , wherein a resource element (RE) is skipped based at least in part on an index value of the RE being greater than one or more other index values of one or more other REs.
10. The wireless communication device of claim 1 , wherein distributed short resource element group (sREG) to short control channel element (sCCE) mapping is enabled for the channel.
11. The wireless communication device of claim 1 , wherein a transmit power of the received channel varies based at least in part on a number of usable resource elements (REs) in a resource block.
12. The wireless communication device of claim 1 , wherein the monitoring period is determined based at least in part on a gap between two modulated symbols of the channel being greater than two resource elements (REs) and based at least in part on the duration of the sTTI.
13. The wireless communication device of claim 1 , wherein the monitoring period is determined based at least in part on one or more orphan resource elements (REs), which are not used for a sPDCCH transmission, not being used for a sPDSCH transmission.
14. The wireless communication device of claim 13 , wherein the one or more processors are configured to receive the sPDSCH transmission using another resource that is different from the one or more orphan REs.
15. A wireless communication device, comprising:
a memory; and
one or more processors coupled to the memory, the one or more processors configured to:
determine, when transmit diversity is enabled for a channel and when using a short transmission time interval (sTTI) with the channel, a transmission period for transmitting the channel,
wherein the sTTI is associated with a duration that is shorter than a duration of a transmission time interval (TTI) used with another channel; and
transmit, during the transmission period, the channel based at least in part on determining the transmission period for transmitting the channel,
wherein the channel is a short physical downlink control channel (sPDCCH) or a short physical downlink shared channel (sPDSCH), and
wherein a resource element (RE) is skipped based at least in part on an index value of the RE being greater than one or more other index values of one or more other REs.
16. The wireless communication device of claim 15 , wherein 2-port space frequency block coding (SFBC) is enabled for the channel; and
wherein the one or more processors are configured to determine the transmission period based at least in part on a configuration of a particular number of configured ports and based at least in part on a 4-port channel state information reference signal (CSI-RS) configuration for one or more sTTIs and based at least in part on a number of useable tones of the channel being an integer multiple of 2.
17. The wireless communication device of claim 15 , wherein a sPDCCH transmission is not transmitted using one or more orphan resource elements (REs) of one or more short resource element groups (sREGs).
18. The wireless communication device of claim 15 , wherein a number of useable tones in each resource block of the channel is an integer multiple of 2.
19. The wireless communication device of claim 15 , wherein 4-port space frequency block coding (SFBC) is enabled for the channel; and
wherein the one or more processors are configured to determine the transmission period based at least in part on a configuration of a particular number of configured ports and based at least in part on an 8-port channel state information reference signal (CSI-RS) configuration for one or more sTTIs and based at least in part on a number of useable tones of the channel being an integer multiple of 4.
20. The wireless communication device of claim 15 , wherein the transmission period is determined based at least in part on one or more orphan resource elements (REs), which are not used for a sPDCCH transmission, not being used for a sPDSCH transmission.
21. The wireless communication device of claim 20 , wherein the one or more processors are configured to transmit the sPDSCH transmission using another resource that is different from the one or more orphan REs.
22. A method of wireless communication performed by a wireless communication device, comprising:
determining, when transmit diversity is enabled for a channel and when using a short transmission time interval (sTTI) with the channel, a monitoring period for receiving the channel,
wherein the sTTI is associated with a duration that is shorter than a duration of a transmission time interval (TTI) used with another channel; and
receiving, during the monitoring period, the channel based at least in part on determining the monitoring period for receiving the channel,
wherein the channel is a short physical downlink control channel (sPDCCH) and the monitoring period is determined based at least in part on a number of useable tones of the channel being an integer multiple of 2,
wherein 2-port space frequency block coding (SFBC) is enabled for the channel,
wherein the wireless communication device is configured to determine the monitoring period based at least in part on a configuration of a particular number of configured ports and based at least in part on a 4-port channel state information reference signal (CSI-RS) configuration for the sTTI, and
wherein the monitoring period omits one or more orphan resource elements (REs) of one or more short resource element groups (sREGs).
23. The method of claim 22 , wherein 4-port space frequency block coding (SFBC) is enabled for the channel; and
wherein the wireless communication device is configured to determine the monitoring period based at least in part on a configuration of a particular number of configured ports and based at least in part on an 8-port channel state information reference signal (CSI-RS) configuration for the sTTI and based at least in part on the number of useable tones of the channel being an integer multiple of 4.
24. The method of claim 22 , wherein the monitoring period is determined based at least in part on a first one or more modulated symbols in a first short resource element group (sREG) and a second one or more modulated symbols in a second sREG.
25. The method of claim 24 , wherein the first sREG and the second sREG are consecutive sREGs with a threshold number of REs and are each associated with the channel.
26. The method of claim 22 , wherein the number of useable tones is determined based at least in part on one or more orphan resource elements (REs) being skipped for channel mapping.
27. The method of claim 22 , wherein a resource element (RE) is skipped based at least in part on an index value of the RE being greater than one or more other index values of one or more other REs.
28. A method of wireless communication performed by a wireless communication device, comprising:
determining, when transmit diversity is enabled for a channel and when using a short transmission time interval (sTTI) with the channel, a transmission period for transmitting the channel,
wherein the sTTI is associated with a duration that is shorter than a duration of a transmission time interval (TTI) used with another channel; and
transmitting, during the transmission period, the channel based at least in part on determining the transmission period for transmitting the channel,
wherein the channel is a short physical downlink control channel (sPDCCH) or a short physical downlink shared channel (sPDSCH), and
wherein a resource element (RE) is skipped based at least in part on an index value of the RE being greater than one or more other index values of one or more other REs.
29. The method of claim 28 , wherein 2-port space frequency block coding (SFBC) is enabled for the channel; and
wherein the wireless communication device is configured to determine the transmission period based at least in part on a configuration of a particular number of configured ports and based at least in part on a 4-port channel state information reference signal (CSI-RS) configuration for one or more sTTIs and based at least in part on a number of useable tones of the channel being an integer multiple of 2.
30. The method of claim 28 , wherein a sPDCCH transmission is not transmitted using one or more orphan resource elements (REs) of one or more short resource element groups (sREGs).