US-12621097-B2 - Dynamic DMRS pattern switching

Abstract

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. In certain configurations, the UE receives a message having Demodulation Reference Signal (DMRS) switching bits that indicate which DMRS pattern is being used of either of a first DMRS pattern or a second DMRS pattern. The UE determines the DMRS pattern being used from the DMRS switching bits. The UE applies the determined DMRS pattern being used to processing of uplink and downlink channels.

Inventors

• Yahia Ahmed Mahmoud Mahmoud Shabara
• Parisa Cheraghi

Assignees

• MEDIATEK INC.

Dates

Publication Date

20260505

Application Date

20230801

Claims (20)

1. 1 . A method of wireless communication performed by a user equipment (UE), the method comprising: receiving a message having Demodulation Reference Signal (DMRS) switching bits that indicate which DMRS pattern is to be used of either of a first DMRS pattern or a second DMRS pattern, wherein the first DMRS pattern supports a first maximum number of orthogonal DMRS ports and provides a first channel estimation performance, wherein the second DMRS pattern supports a second maximum number of orthogonal DMRS ports that is greater than the first maximum number and provides a second channel estimation performance that is degraded relative to the first channel estimation performance, and wherein the DMRS switching bits indicate switching from the second DMRS pattern to the first DMRS pattern when network loading decreases to improve link quality; determining the DMRS pattern to be used from the DMRS switching bits; and applying the determined DMRS pattern to processing of uplink and downlink channels.
2. 2 . The method of claim 1 , wherein the first DMRS pattern has a first length frequency domain (FD)-orthogonal cover code (OCC) and the second DMRS pattern has a second length frequency domain FD-OCC that is different than the first length FD-OCC.
3. 3 . The method of claim 1 , wherein the first DMRS pattern is R15 DMRS with length-2 FD-OCC and the second DMRS pattern is R18 DMRS with length-4 FD-OCC.
4. 4 . The method of claim 1 , wherein the DMRS switching bits include one or more uplink bits that indicate an uplink DMRS pattern used for the uplink channel and one or more downlink bits that indicate a downlink DMRS pattern used for the downlink channel, and the determining the DMRS pattern includes determining each of the uplink DMRS pattern and the downlink DMRS pattern from the DMRS switching bits, and applying the determined DMRS pattern includes applying the determined uplink DMRS pattern to the uplink channel and the determined downlink DMRS pattern to the downlink channel, wherein the uplink DMRS pattern and downlink DMRS pattern are be different.
5. 5 . The method of claim 1 , further comprising reporting to a gNodeB (gNB) that the UE supports dynamic DMRS switching before receiving any Downlink Control Information (DCI) from the gNB.
6. 6 . The method of claim 5 , further comprising: determining that a handover has transpired to a new gNB; reporting to the new gNB that the UE supports dynamic DMRS switching.
7. 7 . The method of claim 5 , wherein the reporting is performed using RRC.
8. 8 . The method of claim 1 , wherein the DMRS switching bits are allocated in DCI and the message having the DMRS switching bits is received via the DCI from a gNB.
9. 9 . The method of claim 1 , wherein the DMRS switching bits are allocated in Radio Resource Control (RRC) information and the message having the DMRS switching bits is received via the RRC information.
10. 10 . A method of wireless communication performed by a gNodeB (gNB), the method comprising: transmitting to a user equipment (UE) a message having Demodulation Reference Signal (DMRS) switching bits that indicate which DMRS pattern is to be used of either of a first DMRS pattern or a second DMRS pattern, wherein the first DMRS pattern supports a first maximum number of orthogonal DMRS ports and provides a first channel estimation performance, wherein the second DMRS pattern supports a second maximum number of orthogonal DMRS ports that is greater than the first maximum number and provides a second channel estimation performance that is degraded relative to the first channel estimation performance, and wherein the DMRS switching bits indicate switching from the second DMRS pattern to the first DMRS pattern when network loading decreases to improve link quality; and applying the indicated DMRS pattern to processing of uplink and downlink channels.
11. 11 . The method of claim 10 , wherein the first DMRS pattern as a first length FD-OCC and the second DMRS pattern has a second length frequency domain (FD)-orthogonal cover code (OCC) that is different than the first length FD-OCC.
12. 12 . The method of claim 10 , wherein the first DMRS pattern is R15 DMRS with length-2 FD-OCC and the second DMRS pattern is R18 DMRS with length-4 FD-OCC.
13. 13 . The method of claim 10 , wherein the DMRS switching bits include one or more uplink bits that indicate an uplink DMRS pattern used for the uplink channel and one or more downlink bits that indicate a downlink DMRS pattern used for the downlink channel, and applying the indicated DMRS pattern includes applying the indicated uplink DMRS pattern to the uplink channel and the indicated downlink DMRS pattern to the downlink channel, wherein the uplink DMRS pattern and downlink DMRS pattern are be different.
14. 14 . The method of claim 10 , further comprising receiving a report from the UE indicating that the UE supports dynamic DMRS switching, and only sending the message having the DMRS switching bits to the UE after receiving the report.
15. 15 . The method of claim 14 , wherein the report is received via a Radio Resource Control (RRC) communication.
16. 16 . The method of claim 14 , wherein the method further includes allocating bits in DCI messaging for the DMRS switching bits, and wherein the DMRS switching bits are transmitted via DCI.
17. 17 . The method of claim 14 , wherein the DMRS switching bits are transmitted via RRC.
18. 18 . The method of claim 10 , further comprising: evaluating network conditions; deciding based on the evaluation whether to transmit to the user equipment (UE) the message with the DMRS switching bits for switching from a current DMRS pattern to a different DMRS pattern.
19. 19 . The method of claim 18 , wherein the network conditions include network loading and channel conditions and the evaluation includes optimization network performance based on the network conditions.
20. 20 . An apparatus for wireless communication, the apparatus being a user equipment (UE), comprising: a memory; and at least one processor coupled to the memory and configured to: receive a message having Demodulation Reference Signal (DMRS) switching bits that indicate which DMRS pattern is to be used of either of a first DMRS pattern or a second DMRS pattern, wherein the first DMRS pattern supports a first maximum number of orthogonal DMRS ports and provides a first channel estimation performance, wherein the second DMRS pattern supports a second maximum number of orthogonal DMRS ports that is greater than the first maximum number and provides a second channel estimation performance that is degraded relative to the first channel estimation performance, and wherein the DMRS switching bits indicate switching from the second DMRS pattern to the first DMRS pattern when network loading decreases to improve link quality; determine the DMRS pattern to be used from the DMRS switching bits; and apply the determined DMRS pattern to processing of uplink and downlink channels.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application claims the benefit of U.S. Provisional Application Ser. No. 63/370,679, entitled “DYNAMIC DMRS PATTERN SWITCHING”, and filed on Aug. 8, 2022, which is expressly incorporated by reference herein in its entirety. BACKGROUND Field The present disclosure relates generally to communication systems, and more particularly, to techniques of adapting DMRS patterns to dynamic conditions. Background The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems. These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. SUMMARY The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. In certain configurations, the UE receives a message having Demodulation Reference Signal (DMRS) switching bits that indicate which DMRS pattern is being used of either of a first DMRS pattern or a second DMRS pattern. The UE determines the DMRS pattern being used from the DMRS switching bits. The UE applies the determined DMRS pattern being used to processing of uplink and downlink channels. In certain configurations the UE reports to the gNB that the UE supports dynamic DMRS switching before receiving any DCI from the gNB. In certain configurations the UE determines that a handover has transpired to a new gNB. In certain configurations, the UE reports to the new gNB that the UE supports dynamic DMRS switching. In certain configurations, the first DMRS pattern has a first length FD-OCC and the second DMRS pattern has a second length frequency domain (FD)-orthogonal cover code (OCC) that is different than the first length FD-OCC. In certain configurations, the first DMRS pattern is R15 DMRS with length-2 FD-OCC and the second DMRS pattern is R18 DMRS with length-4 FD-OCC. In certain configurations, the DMRS switching bits include one or more uplink bits that indicate an uplink DMRS pattern used for the uplink channel and one or more downlink bits that indicate a downlink DMRS pattern used for the downlink channel, and the determining the DMRS pattern includes determining each of the uplink DMRS pattern and the downlink DMRS pattern from the DMRS switching bits, and applying the determined DMRS pattern includes applying the determined uplink DMRS pattern to the uplink channel and the determined downlink DMRS pattern to the downlink channel, wherein the uplink DMRS pattern and downlink DMRS pattern are be different. In certain configurations, the DMRS switching bits are allocated in DCI and the message having the DMRS switching bits is received via the DCI from a gNB. In certain configurations, the DMRS switching bits are allocated in RRC information and the message having the DMRS switching bits is received via the RRC information. In certain configurations, the reporting is performed using RRC. In an aspect of the disclosure, a method, a computer-readable medium, and