CROSS-REFERENCE TO RELATED APPLICATION & PRIORITY CLAIM

This application for Patent is a national stage application under 35 U.S.C. 371 of PCT/CN2018/099945, filed Aug. 10, 2018, which claims the benefit of International Patent Cooperation Treaty Application No. PCT/CN2017/097103, filed Aug. 11, 2017, which are both assigned to the assignee hereof and hereby expressly incorporated by reference herein as if fully set forth below and for all applicable purposes.

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wireless communications systems, and more particularly, to techniques for signaling a transmission rank and/or precoder(s) for an uplink non-codebook based transmission.

INTRODUCTION

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 (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include Long Term Evolution (LTE) systems, 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.

In some examples, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs). In LTE or LTE-A network, a set of one or more base stations may define an e NodeB (eNB). In other examples (e.g., in a next generation or 5G network), a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) in communication with a number of central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more distributed units, in communication with a central unit, may define an access node (e.g., a new radio base station (NR BS), a new radio node-B (NR NB), a network node, 5G NB, gNB, etc.). A base station or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or distributed unit).

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 of an emerging telecommunication standard is new radio (NR), for example, 5G radio access. NR is a set of enhancements to the LTE mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) as well as support beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.

Certain aspects of the present disclosure generally relate to methods and apparatus for configuring uplink non-codebook based transmissions, for example, by signaling a transmission rank indication (TRI) and/or a sounding reference signal (SRS) resource indication (SRI) for uplink non-codebook based transmissions.

Certain aspects of the present disclosure provide a method for wireless communication that may be performed, for example, by a base station (BS). The method generally includes receiving one or more sounding reference signal (SRS) resources from a user equipment (UE). Each SRS resource is associated with one or more precoded SRS ports. The method also includes determining, based on the one or more SRS resources, at least one of a transmission rank or a set of precoders for an uplink transmission. The method further includes signaling an indication of at least one of the one or more SRS resources to the UE.

Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes means for receiving one or more sounding reference signal (SRS) resources from a user equipment (UE). Each SRS resource is associated with one or more precoded SRS ports. The apparatus also includes means for determining, based on the one or more SRS resources, at least one of a transmission rank or a set of precoders for an uplink transmission. The apparatus further includes means for signaling an indication of at least one of the one or more SRS resources to the UE.

Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes a receiver, at least one processor, a transmitter, and a memory coupled to the at least one processor. The receiver is configured to receive one or more sounding reference signal (SRS) resources from a user equipment (UE), wherein each SRS resource is associated with one or more precoded SRS ports. The at least one processor is configured to determine, based on the one or more SRS resources, at least one of a transmission rank or a set of precoders for an uplink transmission. The transmitter is configured to transmit an indication of at least one of the one or more SRS resources to the UE.

Certain aspects of the present disclosure provide a computer-readable medium having computer executable code stored thereon for wireless communication by a UE. The computer executable code includes code for receiving one or more sounding reference signal (SRS) resources from a user equipment (UE). Each SRS resource is associated with one or more precoded SRS ports. The computer executable code also includes code for determining, based on the one or more SRS resources, at least one of a transmission rank or a set of precoders for an uplink transmission. The computer executable code further includes code for signaling an indication of at least one of the one or more SRS resources to the UE.

Certain aspects of the present disclosure provide a method for wireless communication that may be performed, for example, by a user equipment (UE). The method generally includes transmitting one or more sounding reference signal (SRS) resources to a base station, wherein each SRS resource is associated with one or more precoded SRS ports. The method also includes after transmitting the one or more SRS resources, receiving at least one of the one or more of the SRS resources to use for an uplink transmission. The method further includes determining a set of precoders for the uplink transmission based on the indication of the at least one of the one or more SRS resources. The method further includes sending an uplink transmission based in part on the set of precoders.

Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes means for transmitting one or more sounding reference signal (SRS) resources to a base station. Each SRS resource is associated with one or more precoded SRS ports. The apparatus also includes means for receiving at least one of the one or more of the SRS resources to use for an uplink transmission after transmitting the one or more SRS resources. The apparatus further includes means for determining a set of precoders for the uplink transmission based on the indication of the at least one of the one or more SRS resources. The apparatus further includes means for sending an uplink transmission based in part on the set of precoders.

Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes a receiver, at least one processor, a transmitter, and a memory coupled to the at least one processor. The transmitter is configured to transmit one or more sounding reference signal (SRS) resources to a base station. Each SRS resource is associated with one or more precoded SRS ports. The receiver is configured to receive at least one of the one or more of the SRS resources to use for an uplink transmission after transmitting the one or more SRS resources. The at least one processor is configured to determine a set of precoders for the uplink transmission based on the indication of the at least one of the one or more SRS resources. The transmitter is further configured to send an uplink transmission based in part on the set of precoders.

Certain aspects of the present disclosure provide a computer-readable medium having computer executable code stored thereon for wireless communication by a UE. The computer executable code includes code for transmitting one or more sounding reference signal (SRS) resources to a base station. Each SRS resource is associated with one or more precoded SRS ports. The computer executable code also includes code for receiving at least one of the one or more of the SRS resources to use for an uplink transmission after transmitting the one or more SRS resources. The computer executable code further includes code for determining a set of precoders for the uplink transmission based on the indication of the at least one of the one or more SRS resources. The computer executable code further includes code for sending an uplink transmission based in part on the set of precoders.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

