Channel State Information Reporting for Short Transmission Time Intervals

Abstract

Methods, systems, and devices for wireless communication are described. A first CSI reporting configuration can be used for communication using TTIs of a first duration, and a second CSI reporting configuration can be used for communication using TTIs of a second duration. A determination can be made to report CSI based on the first and / or second configuration, and a CSI report can be sent based on the determination. In some cases, the CSI for the first CSI reporting configuration can be determined differently compared to the CSI for the second CSI reporting configuration. For example, the CSI reporting configuration can use different reference resources and / or reference signal resources when calculating the corresponding CSI. In some cases, the first and second CSI reporting configurations can be configured as a first CSI process and a second CSI process, which can operate independently or jointly.

Description

[0001] This application is a divisional application of the patent application with the application date of August 8, 2018, the title of "Channel State Information Reporting for Short Transmission Time Intervals", and the application number of 201880051068.9.

[0002] Cross - References

[0003] This patent application claims the benefit of priority of U.S. Patent Application No. 16 / 057,593, titled "CHANNEL STATE INFORMATION REPORTING FOR SHORT TRANSMISSION TIME INTERVALS", filed on August 7, 2018 by Hosseini et al., and U.S. Provisional Patent Application No. 62 / 544,556, titled "CHANNEL STATE INFORMATION REPORTING FOR SHORT TRANSMISSION TIME INTERVALS", filed on August 11, 2017 by Hosseini et al., both of which have been assigned to the assignee of this application. Technical Field

[0004] Broadly speaking, the following description relates to wireless communication. Specifically, the following description relates to channel state information (CSI) reporting for short transmission time intervals (TTIs). Background Art

[0005] Wireless communication systems have been widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and so on. These systems are capable of supporting communication with multiple users by sharing available system resources, such as time, frequency, and power. Examples of such multi - access systems include fourth - generation (4G) systems (e.g., Long - Term Evolution (LTE) systems or enhanced LTE (LTE - A) systems) and fifth - generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems may employ technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT - S - OFDM). A wireless multi - access communication system may include multiple base stations or network access nodes, each of which simultaneously supports the communication of multiple communication devices (or may be referred to as user equipment (UE)).

[0006] In a multiple access system such as TDMA and OFDMA systems, wireless communication resources can be divided in the time domain into time intervals (e.g., symbol periods, time slots, subframes, etc.) and in the frequency domain into frequency bands (e.g., subcarriers, carriers, subbands, frequency bands, etc.). The divided communication resources can be referred to as resource mappings. In some cases, these time intervals and frequency bands are associated with digital identifiers (e.g., subframe numbers, system frame numbers, carrier numbers, etc.), and the digital identifiers can be used to identify specific communication resources in the resource mapping. For example, when scheduling specific communication resources for one or more specific UEs, the base station can use digital identifiers. In some cases, when scheduling communication resources in a wireless communication system, a minimum scheduling time interval (which can be referred to as TTI) is used. For example, a subframe can be an example of the minimum scheduling time interval, and the base station can schedule a UE to receive or transmit information on communication resources spanning one or more subframes.

[0007] In some examples, a first group of UEs can communicate with the base station using one length of TTI, while a second group of UEs can communicate with the base station using a different length of TTI. For example, the base station can use a short TTI (e.g., a TTI spanning two or three symbol periods) to transmit low-latency information to the first group of UEs and a long TTI (e.g., a TTI spanning 14 symbol periods) to transmit non-low-latency information to the second group of UEs.

[0008] In some cases, CSI reports can be used to increase the reliability of the communication link. For example, a UE can generate a CSI report based on the channel conditions observed by the UE and send the CSI report to the base station. In some cases, the base station can modify the transmission parameters for subsequent transmissions to the UE based on the information received in the CSI report. In some cases, the UE generates a CSI report for communication using a long TTI, and the base station modifies the transmission parameters for subsequent transmissions to the UE based on the CSI report. In some cases, the base station also adopts modified transmission parameters for subsequent transmissions to the UE using a short TTI based on the CSI report.

[0009] However, for communication using a short TTI, these modified transmission parameters may be suboptimal. For example, the CSI report may not take into account rapid changes in the channel conditions experienced by the UE (e.g., burst interference present in two or three symbol periods of a subframe), and the determined transmission parameters may not compensate for these changes. SUMMARY OF THE INVENTION

[0010] Enhanced channel state information (CSI) reporting techniques can be used to generate CSI for communication using low-latency transmission time intervals (TTIs). For example, a first CSI reporting configuration can be used for communication using a TTI of a first duration, and a second CSI reporting configuration can be used for communication using a TTI of a second duration. A determination can be made to report CSI based on the first and / or second configuration, and a CSI report can be sent based on that determination. In some cases, the CSI for the first CSI reporting configuration can be determined differently compared to the CSI for the second CSI reporting configuration. For example, the CSI reporting configuration can use different reference resources and / or reference signal resources when calculating the corresponding CSI. In some cases, the first and second CSI reporting configurations can be configured as a first CSI process and a second CSI process, which can operate independently or jointly.

[0011] A method for wireless communication is described. The method can include: identifying a first CSI reporting configuration associated with a TTI of a first duration; identifying a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; determining whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both; and sending a CSI report based on that determination.

[0012] An apparatus for wireless communication is described. The apparatus can include: a unit for identifying a first CSI reporting configuration associated with a TTI of a first duration; a unit for identifying a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; a unit for determining whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both; and a unit for sending a CSI report based on that determination.

[0013] Another apparatus for wireless communication is described. The apparatus can include a processor, a memory in electrical communication with the processor, and instructions stored in the memory. The instructions can be used to cause the processor to perform the following operations: identify a first CSI reporting configuration associated with a TTI of a first duration; identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; determine whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both; and send a CSI report based on that determination.

[0014] Describes a non - transitory computer - readable medium for wireless communication. The non - transitory computer - readable medium may include instructions that can be used to cause a processor to perform the following operations: identify a first CSI reporting configuration associated with a TTI of a first duration; identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; determine whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both; and transmit a CSI report based on the determination.

[0015] In addition, some examples of the methods, apparatuses, and non - transitory computer - readable media described above may further include: processing, features, units, or instructions for identifying at least one reference resource based on the TTI of the first duration or the TTI of the second duration to determine CSI.

[0016] In some examples of the methods, apparatuses, and non - transitory computer - readable media described above, identifying the at least one reference resource includes: identifying, at least in part based on determining that CSI for the second CSI reporting configuration is to be reported, the TTI of the first duration, where the TTI includes the at least one reference resource.

[0017] In addition, some examples of the methods, apparatuses, and non - transitory computer - readable media described above may further include: processing, features, units, or instructions for generating, at least in part based on the second duration, CSI for the second CSI reporting configuration, where the CSI report includes CSI generated according to the second CSI reporting configuration.

[0018] In some examples of the methods, apparatuses, and non - transitory computer - readable media described above, configuration information including a first period, a second period, a first offset, and a second offset is received. Wherein, identifying the at least one reference resource includes: for the first CSI reporting configuration, identifying a first set of TTIs of the first duration based on the first period and the first offset. In addition, some examples of the methods, apparatuses, and non - transitory computer - readable media described above may further include: processing, features, units, or instructions for identifying a second set of TTIs of the first duration based on the second period and the second offset for the second CSI reporting configuration.

[0019] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving a request for the CSI report during a first TTI of a first duration, wherein the request schedules reporting resources, and wherein identifying the at least one reference resource includes: identifying a second TTI of the first duration at least in part based on determining that CSI for a second CSI report configuration is to be reported, wherein the second TTI may be identified relative to the reporting resources.

[0020] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the request may be received in a third TTI of a second duration that occurs during the first TTI.

[0021] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving a request for the CSI report during a first TTI of a first duration, wherein identifying the at least one reference resource includes: identifying a second TTI of the second duration at least in part based on determining that CSI for a second CSI report configuration is to be reported, wherein the second TTI includes the at least one reference resource and occurs during the first TTI.

[0022] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving a request for the CSI report during a first TTI of a first duration, wherein identifying the at least one reference resource includes: identifying a second TTI of the second duration at least in part based on determining that CSI for a second CSI report configuration is to be reported, wherein the second TTI includes the at least one reference resource and occurs temporally before the first TTI.

[0023] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include processing, features, units, or instructions for the following operation: identifying the at least one reference resource includes: identifying a Multicast Broadcast Single Frequency Network (MBSFN) subframe at least in part based on determining that CSI for a second CSI report configuration is to be reported, wherein the MBSFN subframe includes the at least one reference resource.

[0024] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating CSI for a second CSI reporting configuration based at least in part on a first set of reference signals in a control region, where the MBSFN subframe includes a control region having the first set of reference signals and a data region lacking reference signals.

[0025] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for identifying a second set of reference signals during a TTI prior in time to the MBSFN subframe, where the CSI generated for the second CSI reporting configuration may be generated based at least in part on the second set of reference signals.

[0026] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the second set of reference signals may be located within a predetermined time period relative to the MBSFN subframe, where the predetermined time period is based at least in part on a TTI of a second duration.

[0027] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for associating a first CSI process with a first CSI reporting configuration and associating a second CSI process with a second CSI reporting configuration.

[0028] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating a first CSI report for the first CSI process or a second CSI report for the second CSI process or both, where the CSI report includes the first CSI report or the second CSI report or both.

[0029] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the first CSI process may operate independently of the second CSI process.

[0030] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the first CSI process for the first CSI reporting configuration may be triggered independently of the second CSI process for the second CSI reporting configuration.

[0031] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the first CSI process for the first CSI reporting configuration may be associated with a first period and a first offset, and where the second CSI process for the second CSI reporting configuration may be associated with a second period and a second offset.

[0032] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the first CSI process may operate jointly with the second CSI process.

[0033] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for identifying a first non-zero power (NZP) reference signal resource and a first interference measurement (IM) resource for a first CSI reporting configuration, where the first pattern may be associated with a first period and a first offset. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for determining a second NZP reference signal resource and a second IM resource for a second CSI reporting configuration, where the second pattern may be associated with a second period and a second offset.

[0034] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for determining a zero power (ZP) reference signal resource at least partially based on the first pattern. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for determining a ZP reference signal resource at least partially based on the second pattern.

[0035] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the TTI of the second duration includes a ZP reference signal resource of a third pattern, and wherein, the first IM resource overlaps with the second IM resource, and wherein, the ZP reference signal resource of the third pattern overlaps with the ZP reference signal resource of the fourth pattern.

[0036] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the first NZP reference signal resource overlaps with the second NZP reference signal resource.

[0037] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the second period may be higher than the first period.

[0038] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the resource element density of the second pattern may be lower than that of the first pattern.

[0039] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for identifying a first pattern for a first NZP reference signal resource and a first IM resource for a first CSI reporting configuration, where the first pattern may be associated with a first period and a first offset. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving an indication that one or more NZP reference signal resources and one or more IM resources for a second CSI reporting configuration are present in a TTI of a first duration, where the TTI of the first duration includes a subset of the first NZP reference signal resources of the first pattern and a subset of the first IM resources.

[0040] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, a TTI of a second duration includes one or more NZP reference signal resources of the subset of the first NZP reference signal resources and one or more IM resources of the subset of the first IM resources, where the one or more NZP reference signal resources for the second reporting configuration overlap with the one or more NZP reference signal resources of the subset of the first NZP reference signal resources, and where the one or more IM resources for the second CSI reporting configuration overlap with the one or more IM resources of the subset of the first IM resources.

[0041] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating a first CSI for a first CSI reporting configuration and a second CSI for a second CSI reporting configuration, where the size of the first CSI may be larger than the size of the second CSI. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating the CSI report including the first CSI or the second CSI or both.

[0042] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include processing, features, units, or instructions for the following operations: generating the first CSI includes: determining a first channel quality indicator (CQI) for at least one subband of a first size, and where generating the second CSI includes: determining a second CQI for at least one subband of a second size, where the second size may be larger than the first size.

[0043] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include processing, features, units, or instructions for the following operations: generating a first CSI includes: determining the first CSI according to one of multiple reporting modes, and wherein, generating a second CSI includes: determining the second CSI according to a subset of the multiple reporting modes.

[0044] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving uplink data for transmission having the CSI report, wherein a second CSI of a second size configured for the second CSI report may be generated at least in part based on the uplink data.

[0045] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the CSI report and the data may be transmitted according to a first time interval.

[0046] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating a third CSI configured for the second CSI report at least in part based on the lack of uplink data for transmission, wherein the size of the third CSI may be the same as or larger than the size of the second CSI.

[0047] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the CSI report may be transmitted according to a second time interval, wherein the second time interval may be as long as or longer than the first time interval.

[0048] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving a first downlink transmission via a first downlink resource of a third duration. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for identifying an uplink resource of a third duration. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating a CSI of a first size for a second CSI report configuration. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving a second downlink transmission via a second downlink resource of a third duration. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for identifying an uplink resource of a fourth duration, where the fourth duration may be greater than the third duration. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for generating a CSI of a second size greater than the first size for a second CSI report configuration.

[0049] In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for receiving a plurality of downlink transmissions via a plurality of downlink resources of a third duration, where the plurality of downlink transmissions may be associated with an uplink transmission of a fourth duration. In addition, some examples of the methods, apparatuses, and non-transitory computer-readable media described above may further include: processing, features, units, or instructions for identifying a request for the CSI report in one of the plurality of downlink transmissions.

[0050] A method of wireless communication is described. The method may include: identifying a first CSI report configuration associated with a TTI of a first duration; identifying a second CSI report configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; configuring whether the wireless device reports the CSI of the first CSI report configuration, the CSI of the second CSI report configuration, or both; and receiving a CSI report based on the determination.

[0051] A device for wireless communication is described. The device may include: a unit for identifying a first CSI reporting configuration associated with a TTI of a first duration; a unit for identifying a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; a unit for configuring whether the wireless device reports the CSI of the first CSI reporting configuration, or the CSI of the second CSI reporting configuration, or both; and a unit for receiving a CSI report based on the determination.

[0052] Another device for wireless communication is described. The device may include a processor, a memory in electrical communication with the processor, and instructions stored in the memory. The instructions may be used to cause the processor to perform the following operations: identify a first CSI reporting configuration associated with a TTI of a first duration; identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; configure whether the wireless device reports the CSI of the first CSI reporting configuration, or the CSI of the second CSI reporting configuration, or both; and receive a CSI report based on the determination.

[0053] A non - transitory computer - readable medium for wireless communication is described. The non - transitory computer - readable medium may include instructions for causing a processor to perform the following operations: identify a first CSI reporting configuration associated with a TTI of a first duration; identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration; configure whether the wireless device reports the CSI of the first CSI reporting configuration, or the CSI of the second CSI reporting configuration, or both; and receive a CSI report based on the determination. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Examples of wireless communication systems that support channel state information (CSI) reporting for short transmission time intervals (TTIs) are shown in accordance with various aspects of the present disclosure;

[0055] Figure 2 Examples of wireless communication subsystems that support CSI reporting for short TTIs are shown in accordance with various aspects of the present disclosure;

[0056] Figure 3A and Figure 3B CSI reporting for short TTIs is described in accordance with various aspects of the present disclosure;

[0057] Figure 4 Examples of reference signal configurations that support CSI reporting for short TTIs are shown in accordance with various aspects of the present disclosure;

[0058] Figure 5 Aspects of the present disclosure illustrate examples of processing flows that support CSI reporting for short TTIs;

[0059] Figure 6 and Figure 7 Aspects of the present disclosure illustrate block diagrams of devices that support CSI reporting for short TTIs.

[0060] Figure 8 Aspects of the present disclosure illustrate block diagrams of a system including a user equipment (UE), where the UE supports CSI reporting for short TTIs.

[0061] Figure 9 and Figure 10 Aspects of the present disclosure illustrate block diagrams of wireless devices that support CSI reporting for short TTIs.

[0062] Figure 11 Aspects of the present disclosure illustrate block diagrams of a system including a base station, where the base station supports CSI reporting for short TTIs.

[0063] Figures 12 to 17 Aspects of the present disclosure illustrate methods for CSI reporting for short TTIs. Detailed Description

[0064] A base station and a user equipment (UE) may communicate with each other using a transmission time interval of a first duration (e.g., 1 ms) (or "non-low-latency TTI" or "long TTI") as a minimum scheduling time interval. Thus, the base station and the UE may configure communication processes such as channel state information (CSI) reporting based on the minimum scheduling time interval. For example, a period that supports the latency corresponding to the minimum scheduling time interval may be utilized, and reference resources spanning the minimum scheduling time interval may be used. In some cases, the base station and the UE may also communicate with each other using a TTI of a second duration as the minimum scheduling time interval, where the second duration is shorter than the first duration. In some cases, the TTI of the second duration may be referred to as a "low-latency TTI" or "short TTI" (which is also referred to as sTTI). For example, it may be a 1 orthogonal frequency division multiplexing (OFDM) symbol TTI (the length may be 71.4 μs), a 2 OFDM symbol TTI (the length may be 142.8 μs), a 3 OFDM symbol TTI (the length may be 214.3 μs), or a 7 OFDM symbol TTI (the length may be 0.5 ms). In some cases, communication processes that support communication using a TTI of the first duration may not support communication using a low-latency TTI or may result in a degradation in its performance.

[0065] Therefore, enhanced CSI reporting techniques can be used to generate CSI for communications using low-latency TTIs. For example, a first CSI reporting configuration can be used to report CSI for communications using TTIs of a first duration, and a second CSI reporting configuration can be used to report CSI for communications using TTIs of a second duration. For example, the first CSI reporting configuration can be used for communications using non-low-latency TTIs, and the second CSI reporting configuration can be used for communications using low-latency TTIs.

[0066] CSI reference resources for non-low-latency CSI reporting may not be suitable for supporting low-latency CSI reporting, and thus additional CSI reference resources can be identified for the second CSI reporting configuration. The CSI reference resources can consist of a set of specific communication resources and can be used by a wireless device to determine CSI (e.g., a channel quality indicator (CQI) index). In some cases, a first CSI reference resource is identified for the first CSI reporting configuration, and a second CSI reference resource is identified for the second CSI reporting configuration, where the second reference resource can support low-latency communications. For example, the second CSI reference resource can use a multicast broadcast single frequency network (MBSFN) subframe.

[0067] In some cases, the first and second CSI reference resources span long TTIs. In some cases, CSI for the second CSI reference resource can be generated based on the duration of a short TTI, e.g., by performing transport block size calculations based on the two or three symbol lengths of the short TTI. In some cases, the second CSI reference resource spans short TTIs. In some cases, a trigger for reporting CSI is received in a short TTI, and the second CSI reference resource is within the short TTI. In other cases, a trigger for reporting CSI is received in a short TTI, and the second CSI reference resource is in another short TTI relative to the reporting TTI scheduled for the trigger (e.g., n-n CQI where n CQI acts as a pointer to another short TTI).

[0068] In some cases, the first and second CSI reporting configurations are considered as separate CSI procedures and are operated separately (e.g., triggered or configured). In some cases, these separate CSI procedures are operated jointly (e.g., triggering or configuring one CSI procedure triggers or configures another CSI procedure).

[0069] Reference signal resources configured for non-low latency CSI reporting (e.g., CSI reference signal (RS) and interference measurement (IM) resources) may not support low latency CSI reporting; thus, additional CSI reporting resources (e.g., uplink symbols, time slots or subframes) can be used for low latency configurations. For example, low latency CSI reporting can be supported by identifying RS resources for a second CSI reporting configuration. In some cases, a low latency mode that can include CSI-RS and / or interference measurement (IM) resources can be implemented for the second CSI reporting configuration. For example, the resource element pattern can be configured to be of a higher periodicity compared to the non-low latency mode for the first CSI reporting configuration. In some examples, the CSI-RS resources of the low latency mode can overlap with the CSI-RS resources of the non-low latency mode. In some cases, the CSI-RS resources of the low latency mode can completely overlap with the CSI-RS resources of the non-low latency mode (e.g., the low latency mode can use the CSI-RS resources of the non-low latency mode as its own resources).

[0070] The IM resources for the low latency mode can also overlap with the IM resources for the non-low latency mode. In some cases, the low latency IM resources can have the same pattern as the non-low latency ones, or use a subset of the resource elements (REs) of the pattern for traditional IM resources. For example, when the low latency and non-low latency IM resources overlap in a subframe, they can both be covered by the non-low latency zero power (ZP) CSI-RS pattern. Thus, traditional users can perform rate matching for their reception through the low latency IM resource REs as before. Therefore, the addition of the low latency mode may not affect the performance of traditional users. However, in some cases, the low latency IM resources (and low latency non-zero power (NZP) CSI-RS) can be transmitted more frequently compared to the non-low latency IM and / or NZP CSI-RS resources, and the non-low latency ZP CSI-RS pattern may not always cover the low latency IM resources. In these cases, non-low latency UEs may not be aware of the existence of the low latency IMR / NZP CSI-RS and may not be able to perform rate matching.

[0071] In some cases, the low latency CSI-RS / IM resources can be configured non-periodically, but can be indicated dynamically (e.g., in downlink control information (DCI)). In some cases, the low latency CSI-RS / IM resources can be scheduled semi-persistently (e.g., in downlink control information (DCI)). In some cases, similar to the discussion above, the low latency CSI-RS / IM resources can be scheduled to overlap with the non-low latency CSI-RS / IM resources. For example, in an sTTI of a symbol carrying non-low latency CSI-RS and IM resources, only the low latency CSI-RS / IM resources can be scheduled.

[0072] Low-latency CSI reporting can increase the processing workload of a wireless device; thus, enhanced techniques can be used to process CSI for low-latency CSI reporting. For example, an increased subband size with respect to the subband size used for non-low-latency CSI reporting can be used to calculate CSI for low-latency CSI reporting. In some cases, for low-latency CSI reporting, certain CSI report types can be excluded, or only certain CSI report types can be allowed. For example, low-latency CSI reporting can be limited to: a report type that does not report a precoding matrix indicator (PMI) or a report type that reports a single broadband PMI. A restricted PMI codebook can also be used.

[0073] In some cases, low-latency CSI reporting can be based on whether CSI reporting is used to transmit uplink data. For example, an aperiodic CSI report with uplink data can use a size-restricted CSI and can report the CSI according to an uplink scheduling timeline (e.g., n+4). While an aperiodic CSI report without uplink data can use the CSI with or without a reduced size limit. An aperiodic CSI report without uplink data can also report the CSI according to a timeline that is the same as or longer than the uplink scheduling timeline (e.g., n+6). In some cases, the size of low-latency CSI is based on the asymmetry in downlink and uplink short TTIs. For example, if the downlink TTI spans two symbols and the uplink TTI spans seven symbols, the size of low-latency CSI can be larger.

[0074] The features of the present disclosure introduced above are further described below in the context of a wireless communication system. Subsequently, specific examples of an exemplary processing flow that supports CSI reporting for short TTIs are described. These and other features of the present disclosure are further depicted and described by reference to apparatus diagrams, system diagrams, and flowcharts related to CSI reporting for short TTIs.

[0075] Figure 1In accordance with various aspects of the present disclosure, an example of a wireless communication system 100 is shown, where the wireless communication system 100 supports CSI reporting for short TTIs. The wireless communication system 100 includes a base station 105, a user equipment (UE) 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an enhanced LTE (LTE-A) network, or a New Radio (NR) network. In some cases, the wireless communication system 100 may support enhanced broadband communication, ultra-reliable (i.e., mission-critical) communication, low-latency communication, or communication with low-cost and low-complexity devices. In accordance with aspects of the present disclosure, the wireless communication system 100 may support CSI reporting for short TTIs, specifically, implementing a first CSI reporting configuration for non-low-latency communication and a second CSI reporting configuration for low-latency communication.

[0076] UEs 115 may be dispersed throughout the wireless communication system 100, and each UE 115 may be stationary or mobile. UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a user equipment, or some other suitable term, where "device" may also be used to refer to a unit, a station, a terminal, or a client. Additionally, UE 115 may be a personal electronic device, such as a cellular phone, a Personal Digital Assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may also be referred to as a Wireless Local Loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a Machine Type Communication (MTC) device, etc., which may be implemented in various items such as home appliances, vehicles, meters, etc.

[0077] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices that can provide automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M or MTC may refer to data communication technologies that allow devices to communicate with each other or with the base station 105 without human intervention. In some examples, M2M communication or MTC may include communication from devices integrated with sensors or meters, where the sensors or meters measure or capture information and relay the information to a central server or application, which may make full use of the information or present the information to a person interacting with the program or application. Some UEs 115 may be designed to collect information or implement automated behavior of machines. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based service billing.

[0078] Some UEs 115 may be configured to operate in a power consumption-reduced mode, e.g., half-duplex communication (e.g., a mode that supports one-way communication by transmitting or receiving, but does not support transmitting and receiving simultaneously). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power-saving techniques for the UE 115 include: entering a power-saving "deep sleep" mode when not participating in active communication, or operating on a limited bandwidth (e.g., according to narrowband communication). In some cases, the UE 115 may be designed to support critical functions (e.g., mission-critical functions), and the wireless communication system 100 may be configured to provide ultra-reliable communication to these functions.

[0079] In some cases, the UE 115 is also capable of directly communicating with other UEs 115 (e.g., using peer-to-peer (P2P) or device-to-device (D2D) protocols). One or more of a group of UEs 115 using D2D communication may be located within the geographical coverage area 110 of the base station 105. Other UEs 115 in the group may be located outside the geographical coverage area 110 of the base station 105 or may not be able to receive transmissions from the base station 105. In some cases, a group of UEs 115 communicating via D2D communication may employ a one-to-many (1:M) system in which each UE 115 transmits a signal to each other UE 115 in the group. In some cases, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0080] The base station 105 described herein may include or be referred to by those of ordinary skill in the art as: a base station transceiver, a radio base station, an access point, a radio transceiver, a Node B, an eNodeB (eNB), a next-generation Node B or a giga Node B (any of which may be referred to as a gNB), a home Node B, a home eNodeB or some other suitable term. The wireless communication system 100 may include different types of base stations 105 (e.g., macro cell base stations or small cell base stations). The UE 115 described herein is capable of communicating with various types of base stations 105 and network devices, which include macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

[0081] Base station 105 may communicate wirelessly with UE 115 via one or more base station antennas. Each base station 105 may be associated with a particular geographic coverage area 110, within which communication with respective UEs 115 is supported. Each base station 105 may provide communication coverage for the corresponding geographic coverage area 110 via a communication link 125, and the communication link 125 between the base station 105 and the UE 115 may use one or more carriers. The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105 or a downlink transmission from the base station 105 to the UE 115. The downlink transmission may also be referred to as a forward link transmission, and the uplink transmission may also be referred to as a reverse link transmission.

[0082] The geographic coverage area 110 of the base station 105 may be divided into sectors that only form a part of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for macro cells, small cells, hotspots, or other types of cells, or various combinations thereof. In some examples, the base station 105 may be movable, and thus provide communication coverage for a mobile geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and the overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or different base stations 105. For example, the wireless communication system 100 may include a heterogeneous LTE / LTE-A or NR network, where different types of base stations 105 provide coverage for various geographic coverage areas 110.

[0083] The term "cell" refers to a logical communication entity for communication with the base station 105 (e.g., via a carrier), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) for distinguishing adjacent cells operating via the same or different carriers. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types for providing access to different types of devices (e.g., MTC, narrowband Internet of Things (NB-IoT), enhanced mobile broadband (eMBB), etc.). In some cases, the term "cell" may refer to a part of the geographic coverage area 110 (e.g., a sector) on which the logical entity operates.

[0084] Base stations 105 may also communicate with each other. For example, base stations 105 may communicate directly (e.g., directly between base stations 105) or indirectly (e.g., via the core network 130) with each other over a backhaul link 134 (e.g., via X2 or other interfaces). Base stations 105 may also communicate with the core network 130. For example, base stations 105 may interface with the core network 130 over a backhaul link 132 (e.g., via S1 or other interfaces).

[0085] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may manage non-access stratum (e.g., control plane) functions such as the mobility, authentication, and bearer management of UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transmitted through the S-GW, where the S-GW itself may be connected to the P-GW. The P-GW may provide IP address allocation and other functions. The P-GW may be connected to the network operator's IP services. The operator's IP services may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or packet-switched (PS) streaming services.

[0086] At least some of the network devices (e.g., base stations 105) may include subcomponents such as access network entities, which may be examples of access node controllers (ANCs). Each access network entity may communicate with UEs 115 through a plurality of other access network transmission entities (which may be referred to as radio heads, intelligent radio heads, or transmission / reception points (TRPs)). In some configurations, the various functions of each access network entity or base station 105 may be distributed among various network devices (e.g., radio heads and access network controllers) or may be combined in a single network device (e.g., base station 105).

[0087] The wireless communication system 100 can operate using one or more frequency bands, which are typically in the range of 300 MHz to 300 GHz. Generally, the region from 300 MHz to 3 GHz is called the ultra-high frequency (UHF) region or the decimeter band, because its wavelength ranges from approximately one decimeter to one meter in length. UHF waves can be blocked or redirected by buildings and environmental features. However, these waves can penetrate structures sufficiently to enable a macro cell to serve a UE 115 located indoors. Compared with transmissions at smaller frequencies and longer wavelengths using the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, UHF wave transmissions can be associated with smaller antennas and shorter distances (e.g., less than 100 km).

[0088] In addition, the wireless communication system 100 can also operate in the super-high frequency (SHF) region using a frequency band from 3 GHz to 30 GHz, which is also called the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) band, which can be opportunistically used by devices that can tolerate interference from other users.

[0089] In addition, the wireless communication system 100 can also operate in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), which is also called the millimeter band. In some examples, the wireless communication system 100 can support millimeter wave (mmW) communication between the UE 115 and the base station 105, and the EHF antennas of the corresponding devices may be even smaller and more compact than UHF antennas. In some cases, this can facilitate the use of antenna arrays within the UE 115. However, compared with SHF or UHF transmissions, EHF transmissions may suffer greater atmospheric attenuation and shorter transmission distances. The techniques disclosed herein can be employed in transmissions using one or more different frequency regions; the designated use of frequency bands across these frequency regions may vary due to national or regulatory authorities.

[0090] In some cases, the wireless communication system 100 may use licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may use Licensed-Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in an unlicensed radio frequency spectrum band, wireless devices such as the base station 105 and the UE 115 may use a Listen-Before-Talk (LBT) procedure to ensure that the frequency channel is idle before transmitting data. In some cases, the operation in the unlicensed band may be based on a CA configuration that combines with a CC operating in a licensed band (e.g., LAA). The operation in the unlicensed spectrum may include downlink transmission, uplink transmission, peer-to-peer transmission, or a combination thereof. Duplexing in the unlicensed spectrum may be based on Frequency Division Duplexing (FDD), Time Division Duplexing (TDD), or a combination of both.

[0091] In some cases, the wireless communication system 100 may be a packet-based network that operates according to a hierarchical protocol stack. In the user plane, the communication of the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. In some cases, the Radio Link Control (RLC) layer may perform packet segmentation and reassembly for communication over logical channels. The Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels to transport channels. The MAC layer may also use Hybrid Automatic Repeat reQuest (HARQ) to provide MAC layer retransmissions to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide the establishment, configuration, and maintenance of an RRC connection between the UE 115 and the base station 105 or the core network 130 that supports the radio bearers for user plane data. At the Physical (PHY) layer, the transport channels may be mapped to physical channels.

[0092] Time intervals in LTE or NR can be expressed as multiples of a basic time unit (e.g., it may refer to a sampling period of T s = 1 / 30,720,000 seconds). The time intervals of communication resources can be organized according to radio frames, where each radio frame has a duration of 10 milliseconds (ms), and this frame period can be expressed as T f = 307,200T sThese radio frames can be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame can include 10 subframes numbered from 0 to 9, and each subframe can have a duration of 1 ms. The subframe can be further divided into 2 time slots, each with a duration of 0.5 ms, and each time slot can contain 6 or 7 modulation symbol periods (depending on the length of the cyclic prefix to each symbol period). Excluding the cyclic prefix, each symbol can contain 2048 sampling periods. In some cases, the subframe can be the smallest scheduling unit of the wireless communication system 100, which can be referred to as a TTI. In other cases, the smallest scheduling unit of the wireless communication system 100 can be shorter than a subframe (e.g., it can be one or two symbol periods), or it can be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs), or in a selected component carrier using sTTI).

[0093] In some wireless communication systems, a time slot can be further divided into multiple mini-slots containing one or more symbols. In some instances, the symbol of a mini-slot or a micro-slot can be the smallest unit of scheduling. For example, the duration of each symbol can vary according to the subcarrier spacing or the operating frequency band. In addition, some wireless communication systems can implement time slot aggregation, where multiple time slots or mini-slots are aggregated together and used for communication between the UE 115 and the base station 105.

[0094] The term "carrier" refers to a set of radio frequency spectrum resources with a specified physical layer structure to support communication on the communication link 125. For example, the carrier of the communication link 125 can include a part of the radio frequency spectrum band operating according to the physical layer channels for a given radio access technology. Each physical layer channel can carry user data, control information, or other signaling. The carrier can be associated with a pre-specified frequency channel (e.g., E-UTRA absolute radio frequency channel number (EARFCN)), and can be located according to the channel raster for UE 115 discovery. The carrier can be downlink or uplink (e.g., in FDD mode), or be configured to carry both downlink and uplink communications (e.g., in TDD mode). In some examples, the signal waveform transmitted through the carrier can be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or DFT-s-OFDM).

[0095] For different radio access technologies (e.g., LTE, LTE-A, NR, etc.), the organizational structure of a carrier can be different. For example, communication on a carrier can be organized according to a TTI or a time slot, and each of the TTI or time slot can include user data and control information or signaling for supporting the decoding of the user data. In addition, a carrier can also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc.) and control signaling for coordinating the operation of the carrier. In some examples (e.g., in a carrier aggregation configuration), a carrier can also have acquisition signaling or control signaling for coordinating the operation of the carrier.

[0096] Physical channels can be multiplexed on a carrier according to various techniques. For example, time-division multiplexing (TDM) techniques, frequency-division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques can be used to multiplex physical control channels and physical data channels on a downlink carrier. In some examples, the control information transmitted in a physical control channel can be distributed in different control domains (distributed between a common control domain or a common search space and one or more UE-specific control domains or UE-specific search spaces) in a cascaded manner.

[0097] A carrier can be associated with a specific bandwidth of the radio frequency spectrum. In some examples, the carrier bandwidth can be referred to as the "system bandwidth" of the carrier or the wireless communication system 100. For example, the carrier bandwidth can be one of multiple predetermined bandwidths for a carrier of a specific radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). In some examples, each served UE 115 can be configured to operate on a part or all of the carrier bandwidth. In other examples, some UE 115 can be configured to operate using a narrowband protocol type, where the narrowband protocol type is associated with a predefined part or range in the carrier (e.g., a set of subcarriers or RBs) (e.g., "in-band" deployment of the narrowband protocol type).

[0098] Wireless communication systems such as NR systems can use any combination of licensed, shared, and unlicensed spectrum bands, etc. The flexibility of the eCC symbol duration and subcarrier spacing can allow the use of eCC across multiple spectrums. In some examples, NR shared spectrum can increase frequency utilization and spectral efficiency, especially through vertical (e.g., across frequencies) and horizontal (e.g., across time) sharing of resources.

[0099] In some cases, UE 115 and base station 105 may support retransmission of data to increase the likelihood of successfully receiving the data. HARQ feedback is a technique for increasing the likelihood of correctly receiving data over communication link 125. HARQ may include a combination of error correction (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput of the MAC layer under poor radio conditions (e.g., signal-to-noise ratio conditions). In some cases, a wireless device may support same-slot HARQ feedback, in which case the device may provide HARQ feedback in a particular slot for data received in a previous symbol of that slot. In other cases, the device may provide HARQ feedback in a subsequent slot or according to some other time interval.

[0100] UE 115 and base station 105 may also use CSI reports to increase the reliability of communication. For example, UE 115 may generate a CSI report and send it to base station 105, and base station 105 may modify transmission parameters for subsequent transmissions based on the received CSI report. For example, when UE 115 indicates good channel conditions, base station 105 may use a higher modulation order for subsequent transmissions, increasing the throughput of subsequent communication.

[0101] A CSI report may include multiple feedback components including: a CSI-RS resource indicator (CRI), a rank indicator (RI), a PMI (e.g., PMI-1 and PMI-2), a CQI, or some combination of these components. In some cases, the generated CSI report may vary according to the TTI configuration used for communication. For example, communication using a non-low latency TTI may support up to 8-layer transmissions, while communication using a low latency TTI may support up to 4-layer transmissions. Thus, CSI component calculations may vary based on the TTI configuration.

[0102] The CRI component may be used to indicate which CSI-RS resource is used for the corresponding RI / PMI / CQI measurement value (i.e., which transmission beam in a plurality of beamformed transmissions is preferred). The RI component may be used to recommend the number of transmission layers (i.e., rank) for base station 105 to use in subsequent transmissions based on the signal / interference noise (SINR) of a previous transmission received at UE 115. The size of the RI component may be based on the number of transmission layers used by base station 105.

[0103] The PMI component can be used to signal the preferred weights to be applied during the precoding process, where the signaled weights can increase the S / N ratio of the transmissions received at the UE 115. The PMI component can be divided into two sub-components: PMI-1 and PMI-2. PMI-1 can be associated with the channel conditions of the full frequency band and / or the long-term channel conditions, while PMI-2 can be associated with the channel conditions of a fixed frequency sub-band and / or the short-term channel conditions. In some aspects, PMI-2 can be reported per fixed frequency sub-band. Thus, the size of the PMI-2 component can be proportional to the number of fixed frequency sub-bands within the frequency band used for downlink transmissions to the UE. In certain cases, only the wideband PMI is reported, thereby reducing the size of the PMI component.

[0104] Typically, the UE 115 and the base station 105 agree on a codebook that includes the preferred precoding matrices for downlink transmissions. In some aspects, the codebook includes a long-term sub-codebook associated with the relatively slow changes in the channel conditions, and a short-term sub-codebook associated with the channel conditions that change at an increased rate. Typically, the precoding matrix codebook is specified according to the rank (e.g., rank 1 is associated with the first codebook, rank 2 is associated with the second codebook, etc.). In addition, the number of bits used to convey different precoding matrices typically varies based on the selected codebook. Thus, the sizes of the two PMI components can also vary based on the rank selected by the UE 115. To reduce PMI feedback, the UE 115 can use a subsampled codebook that includes a subset of the precoding matrices available in the full codebook.

[0105] The CQI component can be used to signal channel quality information to the base station 105, which can use the information in the CQI component to select the modulation and coding scheme (MCS) for subsequent transmissions. Similar to the PMI-2 component, the CQI can be reported per fixed frequency sub-band. Thus, the size of the CQI component can be proportional to the number of fixed frequency sub-bands within the frequency band used for downlink transmissions to the UE 115. The CQI component can include a plurality of indices corresponding to specific modulation and coding schemes (e.g., index 0 to index 15).

[0106] To determine the CQI index for each frequency sub-band, the UE 115 may identify a single Physical Downlink Shared Channel (PDSCH) transport block (which may be referred to as a CSI reference resource) that occupies a set of downlink physical resource blocks. In some cases, the CSI reference resource may be identified relative to an uplink subframe designated for reporting CQI. Subsequently, the UE 115 may determine a combination of modulation scheme and transport block size for the PDSCH transport block that corresponds to the highest CQI index associated with the PDSCH transport block being received with a transport block error probability of no more than 0.1. If the combination can be signaled from the transmission on the PDSCH in the CSI reference resource according to a relevant transport block size table, the modulation scheme and transport block size correspond to the CQI index; the modulation scheme is represented by the CQI index; and the combination of transport block size and modulation scheme results in an effective channel coding rate when applied to the reference resource, which may be closest to the coding rate indicated by the CQI index.

[0107] In some examples, the CQI is based on a Common Reference Signal (CRS) included in the downlink transmission (e.g., Transmission Modes (TM) 1 to 8 may use the CRS). In some examples, the CQI is based on a CSI-RS included in the downlink transmission (e.g., TM 9 and 10 may use the CSI-RS). For example, for TM 9, when the parameter pmi-RI reporting is configured by a higher layer and the parameter eMIMO type is not configured by a higher layer, the UE may derive the CQI based on the NZP CSI-RS. In some instances, for TM10, when the parameter eMIMO type is configured by a higher layer, the UE may derive channel measurement values for calculating the CQI corresponding to the CSI process based on the NZP CSI-RS in the CSI-RS resource associated with the CSI process. When the parameter eMIMO type is not configured by a higher layer, the UE may derive interference measurement values for calculating the CQI corresponding to the CSI process based on the CSI-IM resource associated with the CSI process. TM 9 and 10 may support MIMO communication.

[0108] The UE may also use a Full-Dimension MIMO (FD-MIMO) TM, which may be similar to TM 9 and 10. Each of the above TMs may enable non-low latency or low latency transmission or both. The UE 115 may be configured to transmit according to a first transmission mode for non-low latency communication and a second transmission mode for low latency communication. Alternatively, the UE 115 may be configured to send non-low latency and low latency communication according to the same transmission mode.

[0109] In some examples, the CQI index calculation depends on the length of the CSI reference resource. In some cases, certain types of subframes (e.g., MBSFN subframes) are prohibited for CSI reference resources, which may not have CRS in the data domain.

[0110] CSI reporting can be configured periodically or aperiodically. For periodic CSI reporting, the base station 105 can instruct the UE 115 to report CSI according to a specified interval. In some aspects, the specified interval is unique in the time domain or the frequency domain compared to the intervals specified for other UEs 115 in the coverage area. The base station 105 can use the specified resources to expect a response from the UE 115 during the specified interval and associate the information received during that interval with the scheduled UE 115. That is, the base station 105 can identify the UE 115 based on the time and frequency resources used for transmitting the CSI report. In some aspects, physical uplink control channel (PUCCH) resources can be used to report periodic CSI.

[0111] For aperiodic reporting, the base station 105 can send a trigger to the UE 115, which triggers the UE 115 to report CSI. After receiving the trigger, the UE 115 can send CSI to the base station 105. In some aspects, physical uplink shared channel (PUSCH) resources can be used to send aperiodic CSI reports, and the base station 105 can receive the CSI report on the scheduled resources.

[0112] In some examples, multiple CSI processes are configured at one time. Each CSI process can be associated with an index, and for aperiodic reporting, the UE 115 can update a determined number of the lowest-index CSI processes. For example, the UE 115 can update the N lowest-index CSI processes, where N = max(N x -N u , 0), N CSI-P is the maximum number of supported CSI processes, and N u is the number of unreported CSI processes associated with other aperiodic CSI requests for the serving cell. For FDD serving cells: N x = N CSI-P .

[0113] As described above, the UE 115 and the base station 105 may communicate using a TTI of a first size and a TTI of a second size. In some examples, CSI reporting is configured to support a TTI of the first size (e.g., CSI reference resources are configured to span 1 ms), CSI and reference signal resources are configured to have a period that supports 1 ms communication, and so on. To support CSI reporting for a TTI of the second size, the UE 115 and the base station 105 may establish a second CSI configuration that is configured to support a TTI of the second size (e.g., CSI reference resources may be configured to span two or three symbol periods), reference signal resources may be configured with a period that supports low-latency communication, and so on.

[0114] Figure 2 In accordance with various aspects of the present disclosure, an example of a wireless communication subsystem 200 that supports CSI reporting for short TTIs is shown. The wireless communication subsystem 200 may include a UE 115-a and a base station 105-a to perform, and the UE 115-a and the base station 105-a may be examples of the UE 115 and the base station 105 and may communicate with each other as described above with reference to Figure 1 Furthermore, the wireless communication subsystem 200 may also include a downlink 205, an uplink 210, a downlink transmission 215, an uplink transmission 220, a TTI 225, an sTTI 230, and a CSI report 235.

[0115] The downlink 205 may be used to transmit control information and user data from the base station 105-a to the UE 115-a. The downlink 205 may consist of time and frequency resources in a component carrier. The uplink 210 may be used to transmit control information and user data from the UE 115-a to the base station 105-a. The uplink 210 may consist of time and frequency resources in a component carrier. In some cases, the uplink 210 uses a smaller amount of frequency resources compared to the downlink 205.

[0116] Downlink transmission 215 can carry control and / or user data from base station 105-a to UE 115-a. Downlink transmission 215 can also include reference signal resources to enable channel estimation. In some cases, downlink transmission 215 can be sent on a subset of the time and frequency resources used on downlink 205. In some examples, UE 115-a can identify which time and frequency resources are used for downlink transmission 215 based on an authorization received from base station 105-a. Uplink transmission 220 can carry control and / or user data from UE 115-a to base station 105-a. In some cases, uplink transmission 220 can be sent on a subset of the time and frequency resources used on uplink 210. In some examples, UE 115-a can identify which time and frequency resources are scheduled for uplink transmission 220 based on an uplink authorization received from base station 105-a.

[0117] TTI 225 can be the smallest scheduling resource used when scheduling a first configuration of communication between base station 105-a and UE 115-a. For example, for non-low latency communication between base station 105-a and UE 115-a, TTI 225 can span 1 ms. In some cases, resources for downlink transmission 215 and uplink transmission can be scheduled on a TTI-by-TTI basis. In some examples, a first CSI reporting scheme can be used to adopt TTI 225 as the communication with the smallest scheduling interval.

[0118] sTTI 230 can be the smallest scheduling resource used when scheduling a second configuration of communication between base station 105-a and UE 115-a. In some cases, sTTI 230 can be shorter than TTI 225 and can vary in length. For example, for low latency communication between base station 105-a and UE 115-a, sTTI 230 can be a 1 OFDM symbol TTI, a 2 OFDM symbol TTI, a 3 OFDM symbol TTI, or a 7 OFDM symbol TTI. In some examples, a second CSI reporting scheme can be used to adopt sTTI 230 as the communication with the smallest scheduling interval.

[0119] CSI report 235 can carry CSI and can be used to determine transmission parameters that optimize the use of communication resources (e.g., CSI can enable the base station to use a higher MCS to fully utilize a high signal-to-noise ratio (SNR), or when there is a low SNR, use a lower MCS to increase the reliability of the transmission). As described above, CSI report 235 can include CRI, RI, PMI, and / or CQI.

[0120] In some cases, base station 105-a configures UE 115-a to report CSI periodically. In some examples, base station 105-a provides an offset and a period to UE 115-a, which UE 115-a can use to identify specific downlink and uplink resources that support CSI reporting. For example, UE 115-a can identify one or more CSI reporting resources for transmitting CSI reports based on the provided offset and period. UE 115-a can also identify one or more CSI reference resources for calculating CSI values based on the reporting resources. For example, UE 115-a can identify CSI reference resources relative to the CSI reporting resources (e.g., the CSI reference resources can be located n CQI TTIs or sTTIs away from the reporting TTI or sTTI resource, and its location can be represented as n. In some examples, UE 115-a can receive configuration information for low-latency CSI configuration and configuration information for non-low-latency CSI.

[0121] In one example, base station 105-a transmits a downlink transmission 215 to UE 115-a via downlink 205. Downlink transmission 215 can include transmissions configured based on the length of TTI 225 and transmissions configured based on the length of sTTI 230. Downlink transmission 215a can also include CSI reference resources for low-latency CSI reporting configuration and CSI reference resources for non-low-latency CSI reporting configuration. In some cases, UE 115-a can receive downlink transmission 215 and can identify the low-latency CSI reference resources and non-low-latency CSI reference resources in downlink transmission 215. In some cases, UE 115-a can identify low-latency CSI reference resources based on the received low-latency configuration information and can identify non-low-latency CSI reference resources based on the received non-low-latency configuration information.

[0122] In some cases, UE 115-a identifies that the low-latency CSI reference resources span TTI 225. After identifying the low-latency CSI reference resources, UE 115-a can determine the CQI index for the CSI reference resources, as discussed above (e.g., by determining the modulation scheme and transport block size corresponding to the highest CQI index that supports a <0.1 error probability). In some cases, UE 115-a can adopt a two- or three-symbol sTTI length when determining the highest CQI index. In other cases, UE115-a identifies that the low-latency CSI reference resources span sTTI 230.

[0123] In some examples, the UE 115-a identifies that the low-latency CSI reference resource is located in an MBSFN subframe of the downlink transmission 215, or in a subframe that has CRS in the control domain rather than in the data domain. The UE 115-a can use the CRS in the control domain for channel estimation and determine the CQI index. In some cases, the interference statistics in the control domain and the data domain are different, and the UE 115-a can use the CRS received in the data domain of a subframe prior to the MBSFN subframe to estimate interference. In some cases, the UE 115-a limits the number of previous subframes that include CRS in the data domain (which is considered based on low-latency considerations). For example, the UE 115-a can use the CRS in a subframe that occurred 2 to 3 ms prior to the MBSFN subframe. In some cases, using the MBSFN subframe as the low-latency CSI reference resource is based on the transmission mode configured at the UE 115-a. For example, when the UE 115-a is configured to implement any one of transmission modes 1-8, the MBSFN subframe may not be used as the low-latency CSI reference resource.

[0124] In some examples, the non-low-latency CSI report and the low-latency CSI report can be calculated differently (e.g., based on each configuration that supports a different number of transmission layers). In some cases, a first RRC configuration is established for the non-low-latency CSI report, and a second RRC configuration is established for the low-latency CSI report. For periodic reporting, the first RRC configuration can include a first set of reporting modes and a first periodicity, and the second RRC configuration can include a second set of reporting modes and a second periodicity.

[0125] In addition, the base station 105-a can also schedule the UE 115-a to report CSI in an aperiodic manner. For example, the base station 105-a can trigger the UE 115-a to prepare the CSI report 235 during the downlink transmission 215. If the UE 115-a is triggered to prepare the CSI report in the downlink transmission 215, the UE 115-a can determine the CSI based on the reference resources included in the downlink transmission 215. In some cases, the UE 115-a receives multiple downlink sTTIs 230 in the downlink transmission 215, which correspond to a single uplink sTTI 230 scheduled in the uplink transmission 220. In some examples, the trigger can be sent within only one of the multiple downlink sTTIs 230. In some examples, the UE 115-a can determine that one or more CSI resources are located in the downlink transmission 215. For example, the UE 115-a can determine the CSI resources for the low-latency CSI configuration, and there are CSI resources for the non-low-latency CSI configuration in the downlink transmission 215.

[0126] In one example, base station 105-a transmits downlink transmission 215 to UE 115-a over downlink 205. Downlink transmission 215 may include transmissions configured based on TTI 225 and transmissions configured based on sTTI 230. Downlink transmission 215 may also include a trigger for CSI reporting and CSI reference resources for low-latency CSI reporting configuration. In some cases, UE 115-a may receive downlink transmission 215, may identify the CSI reporting trigger, and may identify the low-latency CSI reference resources in downlink transmission 215.

[0127] In some examples, UE 115-a may identify that the low-latency CSI reference resource span carries the TTI 225 of the trigger. In other cases, UE 115-a may identify that the low-latency CSI reference resource span receives the sTTI 230 of the trigger. UE 115-a may use the CRS symbols included in the CSI reference resources to perform interference and channel measurements. In some examples, UE 115-a may identify that the low-latency CSI reference resource is an sTTI 230 in a subframe before the subframe carrying the trigger. For example, UE 115-a may determine that the sTTI 230 is in a subframe that is n CQI subframes away from the subframe carrying the trigger.

[0128] In some examples, non-low-latency CSI reporting and low-latency CSI reporting may be calculated differently (e.g., based on each configuration supporting a different number of transport layers). In some cases, low-latency CSI reporting may be triggered separately or jointly with non-low-latency CSI reporting. For example, the trigger may include a CSI request field, and this field may be set to trigger one or both of the CSI reporting configurations (e.g., a first bit value (e.g., '00') may trigger low-latency CSI reporting, a second bit value (e.g., '01') may trigger non-low-latency CSI reporting, and a third bit value (e.g., '10') may trigger both low-latency and non-low-latency CSI reporting).

[0129] The CSI process capabilities can be specified jointly or separately. For example, separate indices can be allocated to non-low latency CSI processes and low latency CSI reports, or a common index can be allocated. In some examples, the non-low latency CSI report configuration is considered a separate CSI process compared to the low latency CSI report configuration. In some examples, the update of CSI for one or more low latency CSI processes can occur separately from the update of CSI for one or more non-low latency CSI processes. In some cases, the UE can update the CSI for a low latency CSI process based on whether the index allocated to the low latency CSI process is one of the N lowest index low latency CSI processes. For example, UE 115 can update the N lowest index low latency CSI processes (e.g., when a low latency CSI trigger is received), where N = max(N x -N u , 0), N CSI-P is the maximum number of supported low latency CSI processes, and N u is the number of unreported low latency CSI processes. The UE can separately update the CSI for a non-low latency CSI process based on whether the index allocated to the non-low latency CSI process is one of the N lowest index non-low latency CSI processes (e.g., when a non-low latency CSI trigger is received), where N = max(N x -N u , 0), N CSI-P is the maximum number of supported non-low latency CSI processes, and N u is the number of unreported non-low latency CSI processes.

[0130] In some cases, base station 105-a can transmit a reference signal in downlink transmission 215. For example, base station 105-a can transmit a CRS and / or CSI-RS in downlink transmission 215. Base station 105-a can also configure IM resources during downlink transmission 215. For CRS-based CSI reporting (e.g., transmission modes 1-8 and 9 without PMI), UE115-a can use CRS resources to calculate low latency CSI.

[0131] For CSI reports based on CSI-RS and / or IM (e.g., transmission modes 9, 10, and FD-MIMO), CSI-RS and IM resources can be used to support low-latency CSI reporting. Downlink transmission 215 can include CSI-RS resources, which can include NZP and ZP CSI-RS, as well as IM resources configured to support non-low-latency CSI reporting. Non-low-latency CSI-RS and / or IM resources can be configured according to a non-low-latency mode. In some examples, non-low-latency ZP CSI-RS resources are configured to support non-low-latency CSI-RS and IM resources. In some examples, non-low-latency CSI-RS and / or IM resources are configured with a period to support non-low-latency communication. Other UEs can identify the CSI-RS resources in downlink transmission 215 based on this period and perform rate matching thereon.

[0132] In some cases, downlink transmission 215 can also include CSI-RS and IM resources configured to support non-low-latency CSI reporting. Low-latency CSI-RS and / or IM resources can be configured according to a low-latency mode. In some examples, low-latency CSI-RS and / or IM resources are configured with a period to support low-latency communication. Low-latency ZP CSI-RS resources can also be configured to support low-latency CSI-RS and IM resources. In some cases, other UEs (e.g., legacy UEs) may not be aware of low-latency CSI-RS resources and cannot perform rate matching thereon. In some cases, low-latency CSI-RS resources can use the same resources as non-low-latency CSI-RS because if a UE stays in a single location or area, the change in channel conditions is minimal. When low-latency CSI-RS resources use the same resources as non-low-latency CSI-RS resources, other UEs (e.g., legacy UEs) can perform rate matching on both low-latency and non-low-latency CSI-RS resources without explicitly knowing the existence of non-low-latency CSI-RS resources.

[0133] In some cases, low-latency IM resources can be configured to have a higher periodicity compared to non-low-latency IM resources to compensate for short-term or bursty interference caused by scheduling in neighboring cells. In some examples, the IM resources are configured to have a periodicity based on transmissions using sTTI 230. In some examples, the low-latency IM resources are configured to at least partially overlap with non-low-latency IM resources. For example, the low-latency IM resources can use the same resources as the non-low-latency IM resources during subframes carrying non-low-latency ZP CSI-RS. In this way, rate matching of UE 115-a can be facilitated during these subframes. In some examples, the low-latency IM resources are configured to align with non-low-latency IM resources during symbol periods 5-6, 9-10, or 12-13. In some examples, the low-latency IM resource pattern has a lower resource element density than the non-low-latency IM resource pattern. In some cases, the low-latency IM resources use the same resources as the non-low-latency IM resources.

[0134] In some examples, the low-latency CSI-RS and / or IM resources are not configured according to a periodicity, but are dynamically scheduled and indicated (e.g., in DCI) in sTTI 230. In some cases, the low-latency CSI-RS and / or IM resources are scheduled to partially or fully overlap with the non-low-latency CSI-RS and / or IM resources (e.g., the low-latency CSI-RS and / or IM resources can be the same as the non-low-latency CSI-RS and IM resources). For example, the base station 105-a can indicate the presence of the low-latency CSI-RS and / or IM resources during a subframe in DCI. The UE 115-a can identify the presence of the low-latency CSI-RS and / or IM resources to determine the CSI. Other UEs can also identify the presence of the low-latency CSI-RS and / or IM resources accordingly based on the indication and rate matching. In some examples, the base station 105-a schedules the low-latency CSI-RS and / or IM resources to overlap with the non-low-latency CSI-RS and IM resources. For example, the base station 105-a can schedule the low-latency CSI-RS and / or IM resources in an sTTI 230 that includes non-low-latency CSI-RS. The base station 105-a can also trigger an aperiodic CSI report during sTTI 230. The UE 115-a can calculate the CSI based on the low-latency CSI-RS and IM resources, while other UEs can perform rate matching with respect to the low-latency CSI-RS and IM resources.

[0135] In some cases, UE 115-a may calculate CSI for low-latency CSI reporting configurations, non-low-latency CSI reporting configurations, or both. In some cases, UE 115-a may calculate size-limited CSI (which conveys less data than CSI for non-low-latency reporting) or partial CSI for low-latency CSI reporting. For example, relative to the subband size of non-low-latency CQI, UE 115-a may calculate low-latency CQI for an increased subband size. In another example, for low-latency CSI reporting, UE 115-a may exclude certain report types when in use, or include only certain report types. For example, UE 115-a may exclude report types that report wideband and narrowband PMI, and may support report types without PMI (e.g., report types 1-0, 2-0, and 3-0) or report types with a single wideband PMI (e.g., report types 1-1, 2-1, 3-1). UE 115-a may also use a restricted codebook for low-latency CSI reporting.

[0136] In some cases, UE 115-a may calculate CSI for low-latency CSI reporting based on the CSI processing timeline. For example, UE 115-a may calculate larger or smaller CSI based on the amount of time available for calculating CSI. In one example, UE 115-a may receive a trigger for reporting low-latency CSI in a first TTI 225 or sTTI 230 (TTI n or sTTI n), and may be scheduled to transmit a low-latency CSI report and uplink data on a PUSCH resource during a subsequent sTTI 230 (TTI n+4 or sTTI n+4). UE 115-a may calculate a size-limited CSI report based on the interval between receiving the trigger and the scheduled PUSCH resource. In another example, UE 115-a may receive a trigger for reporting low-latency CSI in a first TTI 225 or sTTI 230 (TTI n or sTTI n) without being scheduled to transmit uplink data. UE 115-a may report CSI according to the same interval as above (i.e., during TTI n+4 or sTTI n+4), or UE 115-a may use a longer interval (i.e., during TTI n+6 or sTTI n+6) to report CSI. Relative to the size of CSI generated when transmitting uplink data together with CSI, UE 115-a may generate a larger-size CSI based on more resources available during an sTTI and / or a longer processing time associated with TTI n+6 or sTTI n+6.

[0137] In another example, when configuring asymmetric downlink and uplink sTTIs 230 (e.g., {2,7}), UE 115-a may calculate a complete or near-complete CSI with respect to non-low latency CSI. For example, if the uplink timing is based on the uplink sTTI 230 length, when the downlink sTTI 230 spans 2 symbol periods and the uplink sTTI 230 spans 7 symbol periods, UE 115-a may generate a larger CSI report (e.g., a complete non-low latency CSI report) compared to when the downlink sTTI 230 spans 2 symbol periods and the uplink sTTI 230 spans 2 symbol periods (i.e., due to the longer processing time between the downlink sTTI 230 and the larger uplink sTTI 230).

[0138] In some cases, the rate of low latency CSI reporting is based on the periodicity configured for periodic low latency CSI reporting (e.g., the periodicity may be high to support low latency communication). In other cases, the rate of low latency CSI reporting may be based on the triggering rate of aperiodic low latency CSI reporting (e.g., the triggering may be frequent to support low latency communication). For aperiodic CSI reporting based on CSI-RS / IM resources, if the triggering rate of aperiodic low latency CSI reporting is higher than the period of the CSI-RS and IM resources when there are no new reference signals available for measurement between the first and second triggers, UE 115-a may avoid calculating the CSI.

[0139] Figure 3A According to various aspects of the present disclosure, a CSI report 300-a for short TTIs is described. The CSI report 300-a may illustrate aspects of the transmission between UE 115 and base station 105, as described above with reference to Figures 1 to 2 The CSI report 300-a may include sTTI reference resources (e.g., reference sTTIs 305-a and 325-a), TTI reference resources (e.g., reference TTIs 310-a and reference TTI 330-a), sTTI reporting resources (e.g., reporting sTTIs 315-a and reporting sTTI 335-a), and TTI reporting resources (e.g., reporting TTIs 320-a and reporting TTI 340-a). The CSI report 300-a may also include an sTTI period 345-a and a TTI period 350-a. In some cases, the sTTI period 345-a is shorter than the TTI period 350-a. In some cases, a first transmission mode is configured for non-low latency communication, and a second transmission mode is configured for low latency communication. In other cases, the same transmission mode is configured for both non-low latency and low latency communication.

[0140] The sTTI reference resource or reference sTTI can be used to determine the CSI for low-latency communication. For example, the UE can determine the modulation scheme and transport block size corresponding to the highest CQI index with a <0.1 probability error based on the transport block size of the sTTI. The length of the reference sTTI can vary (e.g., 2 to 3 symbol periods). In some examples, the reference sTTI is configured for the UE periodically based on the provided period and offset. The reference sTTI can be a downlink resource (e.g., sTTI PDSCH resource).

[0141] The TTI reference resource or reference TTI can be used to determine the CSI for non-low-latency communication. For example, the UE can determine the modulation scheme and transport block size corresponding to the highest CQI index with a <0.1 probability error based on the transport block size for the TTI. The size of the reference TTI can be larger than the reference sTTI (e.g., the reference TTI can span 14 symbol periods or subframes). However, in some cases, the reference sTTI can also span the entire subframe. In some examples, the reference TTI is identified relative to the reporting resources configured for the UE periodically. The reference TTI can be a downlink resource (e.g., PDSCH resource).

[0142] The sTTI reporting resource or reporting sTTI can be reserved for the transmission of low-latency CSI reports. The reporting sTTI can be configured for the UE periodically based on the provided period and offset. The reporting sTTI can be an uplink resource (e.g., sTTI PUSCH or PUCCH resource). The length of the reporting sTTI can vary between 1 and 7 symbol periods. In some cases, the low-latency CSI report can be used to transmit uplink data.

[0143] The TTI reporting resource or reporting TTI can be reserved for the transmission of non-low-latency CSI reports. The reporting TTI can be configured for the UE periodically based on the provided period and offset. The reporting TTI can be an uplink resource (e.g., PUSCH or PUCCH resource). In some cases, the non-low-latency CSI report can be used to transmit uplink data.

[0144] In one example, the UE can be configured with a low-latency CSI reporting configuration for sTTI and a non-low-latency CSI reporting configuration for TTI. The base station using the low-latency CSI reporting configuration can configure low-latency CSI reporting resources for the UE, and the UE can identify CSI reference resources relative to the reporting resources (e.g., reference sTTI 305-a and reporting sTTI 315-a). In some cases, the low-latency CSI reporting configuration provides the UE with the sTTI period 345-a and an offset, which the UE uses to determine the location of the low-latency CSI reporting resources. The offset can indicate to the UE the location of the TTI or sTTI relative to the first TTI or sTTI in the subframe.

[0145] In some cases, the UE can identify reference sTTI 305-a and reference sTTI 325-a based on the CSI reporting resources configured for the UE. The UE can generate a low-latency CSI report based on reference sTTI 305-a and 325-a. In some examples, reference sTTI 305-a and 325-a span the entire subframe, in which case the UE can use the sTTI transmission block size (e.g., 2 or 3 symbol periods) to generate the low-latency CSI report. In some examples, the UE can determine that reference sTTI 305-a is an MBSFN subframe or an sTTI in an MBSFN subframe.

[0146] In other examples, reference sTTI 305-a and 325-a span the sTTI (e.g., 2 or 3 symbol periods), in which case the UE can generate the low-latency CSI report based on the length of the reference sTTI. In some cases, the size of the low-latency CSI report is restricted to accommodate timing and / or resource constraints. For example, the low-latency CSI report can be restricted to certain CSI report types (e.g., CSI report types including a single broadband PMI or not reporting PMI at all). In another example, relative to the non-low-latency CSI report reporting CQI, the low-latency CSI report can increase the size of the subband.

[0147] The UE can similarly determine the locations of reporting sTTI 315-a and 335-a based on the provided period and offset. The UE can send the low-latency CSI report to the base station during reporting sTTI 315-a and 335-a.

[0148] The base station may also configure non-low-latency CSI reporting resources for the UE (e.g., with reference to TTI 310-a and reporting TTI 320-a). In some cases, the low-latency CSI reporting and non-low-latency CSI reporting configurations are configured as separate CSI procedures for the UE. In some examples, the low-latency CSI reporting procedure and the non-low-latency CSI reporting procedure are uniquely indexed and thus can be updated separately. For example, UE 115 may update the N lowest-indexed low-latency CSI procedures (e.g., when a low-latency CSI trigger is received), where N = max(N x -N u , 0), N CSI-P is the maximum number of supported low-latency CSI procedures, and N u is the number of unreported low-latency CSI procedures. The UE may separately update the CSI for the non-low-latency CSI procedure based on whether the index assigned to the non-low-latency CSI procedure is one of the N lowest-indexed non-low-latency CSI procedures (e.g., when a non-low-latency CSI is received), where N = max(N x -N u , 0), N CSI-P is the maximum number of supported non-low-latency CSI procedures, and N u is the number of unreported non-low-latency CSI procedures. In other examples, the low-latency CSI reporting procedure and the non-low-latency CSI reporting procedure are jointly indexed and thus can be updated simultaneously.

[0149] The UE may determine the location of the non-low-latency CSI reporting resource based on the TTI period 350-a and an offset. In some cases, the UE may determine that reference TTIs 310-a and 330-a are CSI reference resources, and reporting TTIs 320-a and 340-a are CSI reporting resources. The UE may generate CSI based on reference TTIs 310-a and 330-a and may report the CSI during reporting sTTIs 315-a and 335-a.

[0150] Figure 3B In accordance with various aspects of the present disclosure, an example of CSI reporting 300-b for short TTIs is shown. The CSI reporting 300-b may show aspects of the transmission between UE 115 and base station 105, as described above with reference to Figures 1 - 2As described. The CSI report 300-b may include sTTI reference resources (e.g., reference sTTIs 305-b and 325-b), TTI reference resources (e.g., reference TTI 310-b), sTTI report resources (e.g., reported sTTI 315-b), and TTI report resources (e.g., reported TTI 320-b). The CSI report 300-b may also include CSI report triggers (e.g., sTTI trigger 355-b and TTI trigger 360-b).

[0151] The sTTI reference resources, TTI reference resources, sTTI report resources, and TTI report resources may share the same or similar capabilities as the sTTI reference resources, TTI reference resources, sTTI report resources, and TTI report resources, as discussed with reference to Figure 3A those discussed.

[0152] In one example, the UE may be configured to report low-latency CSI on an aperiodic basis (e.g., based on receiving a CSI report trigger). The UE may also be configured to report non-low-latency CSI on an aperiodic basis. In some cases, the low-latency and non-low-latency CSI report configurations are triggered separately. For example, separate triggers may be specified for the low-latency and non-low-latency CSI report configurations (e.g., sTTI trigger 355-b and TTI trigger 360-b). Or a single trigger may include a field requesting the reporting of CSI for one of these CSI configurations. In other cases, the low-latency CSI report configuration and the non-low-latency CSI report configuration are triggered jointly. For example, a single trigger may cause the UE to report both low-latency and non-low-latency CSI. In some cases, the trigger includes a field for requesting the reporting of CSI for both CSI configurations.

[0153] The UE can receive the sTTI trigger 355-b in the sTTI resource. In some cases, the UE can also identify that the sTTI resource carrying the sTTI trigger is the reference sTTI 325-b for CSI reporting. In other cases, the UE can identify the previous resource (e.g., the reference sTTI 305-b is the reference resource for CSI reporting). In some cases, the reference sTTI 305-b and / or 325-b spans the entire subframe. In some cases, the reference sTTI 305-b and / or 325-b is an MBSFN subframe or the sTTI in an MBSFN subframe. The UE can generate a low-latency CSI report based on receiving the sTTI trigger 355-b. In some cases, the size of the low-latency CSI report is based on timing and / or resource considerations. For example, if the time between receiving the trigger and reporting the CSI is short (e.g., less than one millisecond), the size of the low-latency CSI report can be reduced relative to the non-low-latency CSI report. In another example, if the CSI report is to be sent together with uplink data, the size of the low-latency CSI report can be reduced relative to the non-low-latency CSI report. In some cases, if the CSI report is to be sent without sending uplink data, the size of the low-latency CSI report can be increased or the same as the non-low-latency CSI report.

[0154] The UE can report the low-latency CSI report during the reporting sTTI 315-b. In some examples, the reporting sTTI 315-b spans two or three symbol periods. In other examples, the reporting sTTI 315-b spans seven symbol periods. In some cases, the low-latency CSI report is generated based on the length of the reporting sTTI 315-b or 335-b. For example, if the length of the reporting sTTI 315-b is two or three symbol periods, the size of the low-latency CSI report can be reduced. In another example, if the length of the reporting sTTI 315-b is seven symbol periods, the size of the low-latency CSI report can be the full CSI report (e.g., the same as the size of the non-low-latency CSI report).

[0155] The UE can also receive the TTI trigger 360-b and prepare a non-low-latency CSI report. In some cases, the UE prepares the non-low-latency CSI report based on the reference TTI 310-b. The UE can send the non-low-latency CSI report in the reporting TTI 320-b. In some cases, the reporting TTI 320-b occurs four milliseconds after receiving the TTI trigger 360-b.

[0156] Figure 4In accordance with various aspects of the present disclosure, an example of a reference signal configuration 400 supporting CSI reporting for short TTIs is shown. The reference signal configuration 400 may include a resource block 405, which may include control resources, data resources, CRS resources, CSI-RS resources, and IM resources. The reference signal configuration 400 may also include a first low-latency IM resource 410-a and a second low-latency IM resource 410-b, a first low-latency CSI-RS resource 415-a, a second low-latency CSI-RS resource 415-b, a third low-latency CSI-RS resource 415-c, and reference sTTI candidates 420-a to 420-c.

[0157] The resource block 405 may be configured as a non-low-latency resource block (e.g., the resource block 405 may be configured for 1 ms TTIs, may include 14 symbol periods, which may be labeled 0 to 13). The resource block 405 may also span 12 subcarriers in the frequency domain. The resource block may include control resources, data resources, CRS resources, CSI-RS resources, and IM resources. In some cases, resource blocks (such as the resource block 405) carrying CRS, CSI-RS, and / or IM resources may be transmitted periodically (e.g., every 5 ms) to support non-low-latency communication.

[0158] The control resources may convey configuration information (e.g., transmit power control (TPC) commands and resource block allocation information). The data resources may convey user data. The CRS resources may carry a common reference signal, which may be used to determine channel estimation (e.g., determine SNR) and interference estimation, and may be used for CSI reporting. The CSI-RS resources may carry CSI-specific reference signals, which may also be used to determine channel estimation (since CSI-RS is typically used for data resource channel estimation, and the CSI-RS occupied resources can provide higher-precision channel estimation for data transmission) and interference estimation and for CSI reporting. In some cases, one or more of the CSI-RS resources may be configured as ZP CSI-RS resources. The UE may determine that resource elements configured as ZP CSI-RS resources are allocated for purposes other than CSI reporting (e.g., for interference measurement), and may avoid decoding and rate matching around the resource elements.

[0159] IM resources may be specified during the resource block 405 to measure interference caused by neighboring base stations. For example, the base station may avoid transmitting signals through resources that have been designated as IM resources, and the signals measured by the UE on that resource may represent interference from nearby base stations. In some cases, ZP CSI-RS resources are configured to support IM resources. For example, ZP CSI-RS resources may be configured in one or more resources designated as IM resources.

[0160] In one example, the base station configures low-latency CSI-RS and / or IM resources to support low-latency CSI reporting. For example, the base station may configure additional low-latency CSI-RS and / or IM resources to support low-latency CSI reporting. In some cases, compared with non-low-latency CSI-RS / IM resources, the low-latency CSI-RS and / or IM resources may be configured to have a higher period to compensate for short-term interference (e.g., interference lasting 1-2 symbol periods). The base station may also configure additional low-latency ZP CSI-RS resources based on the low-latency NZP CSI-RS / IM resources.

[0161] In some examples, the base station configures the low-latency CSI-RS resources 415 and the low-latency IM resources 410 based on the non-low-latency CSI-RS and IM resource configurations depicted in Figure 4 . In some examples, the base station configures the low-latency CSI-RS resources to overlap with the non-low-latency CSI-RS resources. For example, the base station may configure the low-latency CSI-RS resources to occupy all the same resources as the non-low-latency CSI-RS resources because when the UE remains stationary or moves within a small area, the short-term variations in the channel are typically minimal. For example, the base station may configure the low-latency CSI-RS resources 415 to use the same resources as the non-low-latency CSI-RS resources in the resource block 405.

[0162] The base station may also configure the low-latency IM resources to partially overlap with the non-low-latency IM resources, but may not configure the low-latency IM resources to occupy all the same resources as the non-low-latency IM resources because the interference from adjacent cells can change rapidly (e.g., within 1-2 symbol periods). In some examples, the base station may configure the low-latency IM resources 410 to use the same resources as the non-low-latency IM resources in the resource block (e.g., resource block 405) carrying the non-low-latency IM resources. By scheduling the low-latency CSI-RS and / or IM resources to overlap with one or more non-low-latency CSI-RS and / or IM resources, non-low-latency UEs can perform rate matching with respect to the low-latency CSI-RS and / or IM resources without knowing their existence.

[0163] In some examples, the base station may dynamically schedule low-latency CSI-RS and / or IM resources and may indicate the locations of the low-latency CSI-RS and / or IM resources. In some cases, the base station may indicate the locations of the low-latency CSI-RS and / or IM resources in the DCI sent in the control resources. As described above, when the base station schedules low-latency CSI-RS and / or IM resources during a resource block (e.g., resource block 405) that is transmitting non-low-latency CSI-RS and IM resources, the base station may schedule the low-latency CSI-RS resource 415 and the low-latency IM resource 410 to completely overlap with the non-low-latency CSI-RS and / or IM resources.

[0164] In some examples, the base station may schedule low-latency CSI-RS and / or IM resources on a semi-persistent basis. For example, the base station may indicate the location of the low-latency CSI-RS and / or IM resources in a first subframe and the period indicating the location of the low-latency CSI-RS and / or IM resources in subsequent subframes. In some cases, the base station may indicate the locations of the CSI-RS and IM resources, the period for the CSI-RS and IM resources in the DCI. The base station may also send activation or deactivation messages for the semi-persistently scheduled CSI-RS and IM resources. In some cases, when after a certain amount of time in the past (which may also be indicated in the DCI), the semi-persistently scheduled CSI-RS and IM resources may be deactivated. The UE may identify the low-latency CSI-RS and / or IM resources in the first subframe based on receiving the semi-persistent CSI-RS and / or IM resource trigger, and may identify the subsequent low-latency CSI-RS and / or IM resources in subsequent subframes based on the periodicity received in the DCI. In some cases, the UE may continue to identify the subsequent low-latency CSI-RS and / or IM resources until it receives a trigger to deactivate the semi-persistently scheduled low-latency CSI-RS and / or IM resources (e.g., received from the base station or based on the expiration of the corresponding timer).

[0165] Also as discussed above, when non-low-latency CSI-RS and / or IM resources are configured for a subframe, the base station may map the low-latency CSI-RS and / or IM resources to the non-low-latency CSI-RS and / or IM resources. Subsequently, the base station may configure one or more sTTIs based on this mapping. For example, the base station may identify the reference sTTI candidate 420-a and the reference sTTI candidate 420-b. As Figure 4As shown, reference sTTI candidate 420-a spans two symbol periods (e.g., covering symbol periods 5 and 6), and includes a first low-latency CSI-RS resource 415-a and a low-latency IM resource 410-a, which are mapped to one or more of the non-low-latency CSI-RS and IM resources. While reference sTTI candidate 420-a spans three symbol periods (e.g., covering symbol periods 8-10), and includes a second low-latency CSI-RS resource 415-b and a second low-latency IM resource 410-b, which are mapped to one or more of the non-low-latency CSI-RS and IM resources. In some cases, reference sTTI candidate 420-c covering symbol periods 12 and 13 may include a third low-latency CSI-RS resource 415-c, but may not include any low-latency IM resources. In some cases, reference sTTI candidate 420-c may not be configured or recognized as a reference resource for CSI reporting.

[0166] Figure 5 In accordance with various aspects of the present disclosure, an example of a processing flow 500 for CSI reporting for short TTI is shown. The processing flow 500 may be performed by UE 115-b and base station 105-b, which may be examples of UE 115 and base station 105 described below with reference to Figures 1 to 2 In some examples, a base station such as base station 105-b and a UE such as UE 115-b may configure and report CSI for long TTI, short TTI, or both.

[0167] At step 505, base station 105-b may identify one or more CSI reporting configurations for UE 115-b. In some examples, base station 105-b may identify a low-latency CSI reporting configuration and a non-low-latency CSI reporting configuration. In some cases, base station 105-b may determine a first period and offset for a low-latency CSI reporting resource, and a second period and offset for a low-latency CSI reporting resource configured for UE 115-b.

[0168] At step 510, base station 105-b and UE 115-b may exchange high-layer signaling (e.g., RRC signaling). For example, UE 115-b may signal to base station 105-b its ability to communicate using short TTIs, and base station 105-b may send configuration information such as CSI report configuration information to UE 115-b. In some cases, base station 105-b establishes a first RRC configuration for low-latency CSI reporting and a second RRC configuration for non-low-latency CSI reporting for UE 115-b. In some cases, the low-latency CSI report configuration corresponds to a low-latency CSI process, and the non-low-latency CSI report configuration corresponds to a separate CSI process. In some examples, a separate index is assigned to the low-latency CSI process from the non-low-latency CSI process, and when a CSI trigger is received, it is updated independently of the non-low-latency CSI process. In other examples, an index common to the low-latency CSI process and the non-low-latency process is assigned, and they are updated simultaneously when a CSI trigger is received.

[0169] At step 515, base station 105-b may configure CSI reporting resources for UE 115-b. In some cases, base station 105-b may configure low-latency CSI reporting resources for UE 115-b based on a first period and offset. Base station 105-b may also configure reference signal resources (e.g., CRS and low-latency CSI-RS) and low-latency IM resources. In some cases, base station 105-b schedules the low-latency reference signal resources and IM resources according to another period. In other cases, base station 105-b dynamically schedules the low-latency reference signal resources and IM resources and indicates the presence of low-latency resources in the DCI.

[0170] At step 520, UE 115-b may identify the low-latency CSI report configuration and the non-low-latency CSI report configuration. In some cases, the CSI report configuration may provide CSI report configuration information (e.g., period and offset) for both low-latency and non-low-latency CSI resources. In some cases, the CSI report configuration may indicate that an aperiodic CSI report is configured for one or both of the CSI report configurations. UE 115-b may also determine whether the low-latency CSI report configuration and the non-low-latency CSI report configuration are specified as separate processes, and determine whether the CSI processes are triggered jointly or independently.

[0171] At step 525, UE 115-b can determine which reporting configurations are actively used for reporting CSI. For example, UE 115-b can determine that a low-latency CSI reporting configuration is enabled or a non-low-latency CSI reporting configuration is enabled, or both. In some cases, UE 115-b can determine that the low-latency CSI reporting configuration corresponds to a first CSI process and the non-low-latency CSI reporting configuration corresponds to a second CSI process.

[0172] At step 530, base station 105-b can send a CSI report trigger. In some cases, base station 105-b sends a CSI report trigger to schedule UE 115-b to report CSI irregularly. In some examples, base station 105-b sends a single trigger that triggers both low-latency and non-low-latency CSI reports. In some cases, the trigger is configured with fields for requesting a low-latency CSI report (e.g., via signaling 00) or a non-low-latency CSI report (e.g., via signaling 01) or both (e.g., via signaling 10). In other examples, base station 105-b sends one trigger for low-latency CSI reporting and a different trigger for non-low-latency CSI reporting.

[0173] At step 535, UE 115-b can identify CSI reporting resources, such as CSI reference resources, CSI reporting resources, and reference signals that support CSI reporting (e.g., CRS, CSI-RS). UE 115-b can also identify IM resources for measuring interference from nearby base stations. In some cases, UE 115-b identifies the CSI reporting resources based on the received first period and offset and the position of the CSI reference resource relative to the CSI reporting resource. In some examples, UE 115-b can identify the CSI reporting resources and reference resources relative to the received trigger or scheduled reporting resources. For example, the reference resource can be offset by 4 milliseconds from the trigger or reporting resource, and the reference resource can be included in the TTI or sTTI in which the trigger is received. Or, the reference resource can be a certain number of sTTIs (n CSI ) or TTIs (n CQI ) before the scheduled reporting resource.

[0174] At step 540, UE 115-b may also identify one or more reference signal resources that support CSI reporting based on a known reference signal pattern. In some cases, UE 115-b only identifies CSI-RS and IM resources for CSI reporting for certain transmission modes (e.g., TM 9, TM10, or FD-MIMO TM). In some cases, UE 115-b may determine that a low-latency reference signal resource with its own periodicity and offset has been configured for sTTI communication. In other cases, UE 115-b may determine that the low-latency reference signal resource overlaps with a non-low-latency reference signal resource. For example, UE 115-b may determine that the low-latency CSI-RS resource is the same as the non-low-latency CSI-RS resource, and when the sTTI coverage is scheduled to carry the symbol period of the non-low-latency IM resource, the low-latency IM resource is the same as the non-low-latency IM resource. In some cases, UE 115-b may identify the one or more reference signal resources based on receiving an indication that the sTTI includes low-latency CSI-RS and IM resources. In some examples, when the sTTI covers non-low-latency CSI-RS and IM resources, the indicated low-latency CSI-RS and / or IM resources may be mapped to the non-low-latency CSI-RS and / or IM resources.

[0175] At step 545, UE 115-b may generate a CSI report based on the identified CSI reference resources and / or the identified CSI-RS / IM resources. In some cases, UE 115-b generates a reduced-size CSI report for low-latency CSI reporting as compared to the CSI report generated for non-low-latency CSI reporting. UE 115-b may generate a reduced low-latency CSI report by reporting CSI for fewer subbands than the non-low-latency CSI report (e.g., by reporting wider subbands). Additionally, UE 115-b may also generate a reduced low-latency CSI report by restricting the CSI report to certain types. For example, UE 115-b may exclude CSI reports that include wideband and narrowband PMI. Or, UE 115-b may use a restricted PMI codebook when generating the reduced low-latency CSI report.

[0176] In some cases, UE 115-b may generate a low-latency CSI report based on whether uplink data is scheduled to be sent together with the CSI report. For example, for an aperiodic CSI report, if the low-latency CSI report is scheduled to report CSI together with uplink data, UE 115-b may generate a low-latency CSI report with a reduced size as described above. However, if the low-latency CSI report is scheduled to report CSI without having uplink data, UE 115-b may generate a low-latency CSI report with a larger size (e.g., larger than the reduced-size low-latency CSI report or having the same size as a non-low-latency CSI report). In some examples, the low-latency CSI report resource is scheduled to be sent during a low-latency CSI report resource with a time offset from the aperiodic trigger. In some cases, if the time offset is long, UE 115-b generates a low-latency CSI report with a larger size. If there is a size imbalance between the downlink sTTI and the uplink sTTI for reporting low-latency CSI, UE 115-b may also generate a low-latency CSI report with a larger size.

[0177] At step 550, UE 115-b may send a CSI report to base station 105-b, and base station 105-b may receive the CSI report. In some cases, UE 115-b may send a low-latency CSI report during a determined low-latency CSI report resource.

[0178] Figure 6 According to aspects of the present disclosure, a block diagram 600 of a wireless device 605 that supports CSI reporting for short TTIs is shown. Wireless device 605 may be an example of some aspects of user equipment (UE) 115 as described herein. Wireless device 605 may include a receiver 610, a UE communication manager 615, and a transmitter 620. In addition, wireless device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0179] Receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CSI reporting for short TTIs, etc.). The information may be conveyed to other components of the device. Receiver 610 may be an example of some aspects of transceiver 835 as described Figure 8 herein. Receiver 610 may use a single antenna or a set of antennas.

[0180] The receiver 610 may receive a first downlink transmission via a first downlink resource of a third duration, receive a second downlink transmission via a second downlink resource of the third duration, and receive a set of downlink transmissions via a set of downlink resources of the third duration, where the set of downlink transmissions is associated with an uplink transmission of a fourth duration.

[0181] The UE communication manager 615 may be an example of some aspects of the UE communication manager 815 described with reference to Figure 8 The UE communication manager 615 and / or at least some of its respective sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof that execute the functions described in this disclosure may execute the functions of the UE communication manager 615 and / or at least some of its respective sub-components.

[0182] The UE communication manager 615 and / or at least some of its respective sub-components may be physically distributed across multiple locations, including being distributed such that a portion of the functionality is implemented at different physical locations via one or more physical devices. In some examples, in accordance with aspects of this disclosure, the UE communication manager 615 and / or at least some of its respective sub-components may be separate and distinct components. In other examples, in accordance with aspects of this disclosure, the UE communication manager 615 and / or at least some of its respective sub-components may be combined with one or more other hardware components, where such hardware components include, but are not limited to: I / O components, transceivers, network servers, another computing device, one or more other components described in this disclosure, or combinations thereof.

[0183] The UE communication manager 615 may: identify a first CSI reporting configuration associated with a TTI of a first duration, identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration, and determine whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both.

[0184] The transmitter 620 may send signals generated by other components of the device. In some examples, the transmitter 620 may be collocated with the receiver 610 in a transceiver module. For example, the transmitter 620 may be with reference to Figure 8Examples of some aspects of the transceiver 835 described. The transmitter 620 may use a single antenna or may also use a set of antennas. The transmitter 620 may send a CSI report based on the determination. In some cases, the CSI report and data are sent according to a first time interval. In some cases, the CSI report is sent according to a second time interval that is as long as or longer than the first time interval.

[0185] Figure 7 In accordance with aspects of the present disclosure, a block diagram 700 of a wireless device 705 supporting CSI reporting for short TTIs is shown. The wireless device 705 may be an example of some aspects of the wireless device 605 or UE 115 as described with reference to Figure 6 The wireless device 705 may include a receiver 710, a UE communication manager 715, and a transmitter 740. In addition, the wireless device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0186] The receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CSI reporting for short TTIs, etc.). The information may be conveyed to other components of the device. The receiver 710 may be an example of some aspects of the transceiver 835 described with reference to Figure 8 The receiver 710 may use a single antenna or a set of antennas.

[0187] The UE communication manager 715 may be an example of some aspects of the UE communication manager 815 described with reference to Figure 8 The UE communication manager 715 may also include a CSI manager 720, a CSI reporter 725, a CSI resource identifier 730, and a CSI generator 735. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses).

[0188] The CSI manager 720 may identify a first CSI report configuration associated with a TTI of a first duration and identify a second CSI report configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The CSI resource identifier 730 may identify at least one reference resource to determine CSI according to the TTI of the first duration or the TTI of the second duration. The CSI reporter 725 may determine whether to report CSI for the first CSI report configuration or the second CSI report configuration, or both. The transmitter 740 may send a CSI report based on the determination.

[0189] The CSI manager 720 may receive a request for a CSI report during a first TTI of a first duration, where the request may schedule reporting resources, and the CSI resource identifier 730 may identify the at least one reference resource by identifying a second TTI of the first duration. In some cases, the CSI resource identifier 730 identifies a second TTI of the first duration based on determining that CSI for a second CSI reporting configuration is to be reported, where the second TTI is identified relative to the reporting resources. In some cases, the CSI resource identifier 730 may identify the at least one reference resource by identifying a second TTI of a second duration. The CSI resource identifier 730 may identify a second TTI of the second duration at least in part based on determining that CSI for a second CSI reporting configuration is to be reported, where the second TTI includes the at least one reference resource and occurs during the first TTI. Additionally, the CSI manager 720 may also receive a request for a CSI report during a first TTI of a first duration, and the CSI resource identifier 730 may identify the at least one reference resource by: identifying a second TTI of a second duration based on determining that CSI for a second CSI reporting configuration is to be reported, where the second TTI includes the at least one reference resource and occurs temporally before the first TTI. In some cases, the CSI manager 720 identifies a request for a CSI report within one of a set of downlink transmissions.

[0190] Additionally, the CSI manager 720 may also associate a first CSI process with a first CSI reporting configuration and a second CSI process with a second CSI reporting configuration. In some cases, the request is received in a third TTI of a second duration that occurs during the first TTI. In some cases, the first CSI process operates independently of the second CSI process. In some cases, the first CSI process for the first CSI reporting configuration is triggered independently of the second CSI process for the second CSI reporting configuration. In some cases, the first CSI process for the first CSI reporting configuration is associated with a first period and a first offset, and where the second CSI process for the second CSI reporting configuration is associated with a second period and a second offset. In some cases, the first CSI process operates jointly with the second CSI process.

[0191] In addition, the CSI resource identifier 730 can also identify the at least one reference resource in the following manner: based on determining that CSI for a second CSI reporting configuration is to be reported, identify a TTI of a first duration, where the TTI includes the at least one reference resource. In some cases, the CSI resource identifier 730 can receive configuration information including a first period, a second period, a first offset, and a second offset, and for the first CSI reporting configuration, identify a first set of TTIs of a first duration based on the first period and the first offset to identify the at least one reference resource. In some cases, the CSI resource identifier 730 can identify the at least one reference resource in the following manner: based on determining that CSI for a second CSI reporting configuration is to be reported, identify an MBSFN subframe, where the MBSFN subframe includes the at least one reference resource. The CSI resource identifier 730 can identify a second set of reference signals during a TTI that is temporally before the MBSFN subframe, and the CSI generator 735 can generate CSI for the second CSI reporting configuration based on the second set of reference signals. In some cases, the second set of reference signals is within a predetermined time period relative to the MBSFN subframe, where the predetermined time period is at least partially based on a TTI of a second duration. In addition, the CSI resource identifier 730 can also identify a second set of TTIs of a first duration for the second CSI reporting configuration based on the second period and the second offset.

[0192] The CSI resource identifier 730 can also identify a first pattern for a first NZP reference signal resource and a first interference measurement (IM) resource for a first CSI reporting configuration, where the first pattern is associated with a first period and a first offset. In addition, the CSI resource identifier 730 can also determine a second pattern for a second NZP reference signal resource and a second IM resource for a second CSI reporting configuration, where the second pattern is associated with a second period and a second offset. In some cases, the second period is higher than the first period. In some cases, the first IM resource overlaps with the second IM resource. The CSI resource identifier 730 can also determine a third pattern for a zero power (ZP) reference signal resource based on the first pattern. In some cases, the TTI of the second duration includes one or more NZP reference signal resources of the subset of the first NZP reference signal resource and one or more IM resources of the subset of the first IM resource. In some cases, the one or more NZP reference signals resources for the second reporting configuration overlap with the one or more NZP reference signal resources of the subset of the first NZP reference signal resource. In some cases, the one or more IM resources for the second CSI reporting configuration overlap with the one or more IM resources of the subset of the first IM resource.

[0193] In some cases, the first NZP reference signal resource overlaps with the second NZP reference signal resource. In some cases, the resource element density of the second mode is lower than that of the first mode. In some cases, the CSI resource identifier 730 may receive an indication of the presence of one or more NZP reference signal resources and one or more IM resources for a second CSI reporting configuration in a TTI of a first duration, where the TTI of the first duration includes a subset of the first NZP reference signal resource and the first IM resource of the first mode. In some cases, the TTI of the second duration includes one or more of the first NZP reference signal resource and the first IM resource of the subset, and the one or more NZP reference signal resources and the one or more IM resources for the second CSI reporting configuration overlap with the one or more NZP reference signal resources and the first IM resource of the subset.

[0194] The CSI resource identifier 730 may identify an uplink resource of a third duration. In some cases, the CSI resource identifier 730 may also identify an uplink resource of a fourth duration, which is greater than the third duration.

[0195] The CSI generator 735 may generate CSI for a second CSI reporting configuration based on the second duration, where the CSI report includes CSI generated according to the second CSI reporting configuration. In addition, the CSI generator 735 may also generate, for the second CSI reporting configuration, a second CSI of a second size that is larger than a first size, generate a first CSI report for a first CSI process or a second CSI report for a second CSI process or both, where the CSI report includes the first CSI report or the second CSI report or both. In addition, the CSI generator 735 may also generate a first CSI for a first CSI reporting configuration and a second CSI for a second CSI reporting configuration, where the size of the first CSI is larger than the size of the second CSI. In addition, the CSI generator 735 may also generate a CSI report including the first CSI or the second CSI or both. In addition, the CSI generator 735 may also generate CSI for a second CSI reporting configuration based on a first set of reference signals in a control domain, where an MBSFN subframe includes a control domain with the first set of reference signals and a data domain lacking reference signals.

[0196] In some cases, generating the first CSI includes determining the first CSI according to one of a set of reporting modes, and generating the second CSI includes determining the second CSI according to a subset of the set of reporting modes. In addition, the CSI generator 735 may also receive uplink data for transmission with a CSI report, where, based on the uplink data, a second CSI of a second size is generated for a second CSI reporting configuration.

[0197] In addition, the CSI generator 735 may also generate a third CSI for the second CSI report configuration based on the lack of uplink data for transmission, where the size of the third CSI is the same as or larger than the size of the second CSI. The CSI generator 735 may generate a CSI of a first size for the second CSI report configuration, and generating the first CSI includes: determining a first CQI for at least one subband of the first size, and where generating the second CSI includes: determining a second CQI for at least one subband of a second size that is larger than the first size.

[0198] The transmitter 740 may transmit signals generated by other components of the device. In some examples, the transmitter 740 may be collocated with the receiver 710 in a transceiver module. For example, the transmitter 740 may be an example of some aspects of the transceiver 835 described with reference to Figure 8 The transmitter 740 may use a single antenna or may also use a set of antennas.

[0199] Figure 8 According to aspects of the present disclosure, a block diagram of a system 800 including a device 805 is shown, where the device 805 supports CSI reporting for short TTIs. The device 805 may be an example of the wireless device 605, the wireless device 705, or the UE 115 described above, for example, with reference to Figure 6 and Figure 7 or may include components of the wireless device 605, the wireless device 705, or the UE 115. The device 805 may include components for two-way voice and data communication, which include components for sending communications and components for receiving communications, including a UE communication manager 815, a processor 820, a memory 825, software 830, a transceiver 835, an antenna 840, and an I / O controller 845. These components may communicate electrically via one or more buses (e.g., bus 810). The device 805 may communicate wirelessly with one or more base stations 85.

[0200] The processor 820 may include intelligent hardware devices (e.g., a general-purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 820 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 820. The processor 820 may be configured to execute computer-readable instructions stored in the memory to perform various functions (e.g., functions or tasks supporting CSI reporting for short TTIs).

[0201] The memory 825 may include a random access memory (RAM) and a read-only memory (ROM). The memory 825 may store computer-readable, computer-executable software 830 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, specifically, the memory 825 may contain a basic input / output system (BIOS) that may control basic hardware or software operations (e.g., interaction with peripheral components or devices).

[0202] The software 830 may include code for implementing aspects of the present disclosure, including code for supporting CSI reporting for short TTIs. The software 830 may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software 830 may not be directly executed by the processor but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0203] The transceiver 835 may communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 835 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Additionally, the transceiver 835 may also include a modem to modulate a packet, provide the modulated packet to the antenna for transmission, and demodulate a packet received from the antenna.

[0204] In some cases, the wireless device may include a single antenna 840. However, in some cases, the device may have more than one antenna 840 that are capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0205] The I / O controller 845 may manage input and output signals for the device 805. The I / O controller 845 may also manage peripheral devices not integrated into the device 805. In some cases, the I / O controller 845 may represent a physical connection or port for external peripheral devices. In some cases, the I / O controller 845 may use an operating system such as or another known operating system. In other cases, the I / O controller 845 may represent a modem, keyboard, mouse, touch screen, or similar device, or interact with such devices. In some cases, the I / O controller 845 may be implemented as part of the processor. In some cases, a user may interact with the device 805 via the I / O controller 845 or via the hardware components controlled by the I / O controller 845.

[0206] Figure 9In aspects according to the present disclosure, a block diagram 900 of a wireless device 905 that supports CSI reporting for short TTIs is shown. The wireless device 905 can be an example of some aspects of the base station 105 as described herein. The wireless device 905 can include a receiver 910, a base station communication manager 915, and a transmitter 920. In addition, the wireless device 905 can also include a processor. Each of these components can communicate with one another (e.g., via one or more buses).

[0207] The receiver 910 can receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CSI reporting for short TTIs, etc.). The information can be transmitted to other components of the device. The receiver 910 can be an example of some aspects of the transceiver 1135 described with reference to Figure 11 The receiver 910 can use a single antenna or a set of antennas.

[0208] The base station communication manager 915 can be an example of some aspects of the base station communication manager 1115 described with reference to Figure 11 The base station communication manager 915 and / or at least some of its various sub-components can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof for performing the functions described in the present disclosure can execute the functions of the base station communication manager 915 and / or at least some of its various sub-components.

[0209] The base station communication manager 915 and / or at least some of its various sub-components can be physically distributed in multiple locations, including being distributed such that a portion of the functionality is implemented in different physical locations by one or more physical devices. In some examples, according to various aspects of the present disclosure, the base station communication manager 915 and / or at least some of its various sub-components can be separate and distinct components. In other examples, according to various aspects of the present disclosure, the base station communication manager 915 and / or at least some of its various sub-components can be combined with one or more other hardware components, where these hardware components include, but are not limited to: I / O components, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or combinations thereof.

[0210] The base station communication manager 915 may: identify a first CSI reporting configuration associated with a TTI of a first duration, identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration, and configure the wireless device to report CSI of the first CSI reporting configuration, or the second CSI reporting configuration, or both.

[0211] The transmitter 920 may send signals generated by other components of the device. In some examples, the transmitter 920 may be collocated with the receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of some aspects of the transceiver 1135 described with reference to Figure 11 The transmitter 920 may use a single antenna or may also use a set of antennas.

[0212] The transmitter 920 may send a CSI report based on the determination.

[0213] Figure 10 According to aspects of the present disclosure, a block diagram 1000 of a wireless device 1005 supporting CSI reporting for short TTIs is shown. The wireless device 1005 may be an example of some aspects of the wireless device 905 or the base station 105 described with reference to Figure 9 The wireless device 1005 may include a receiver 1010, a base station communication manager 1015, and a transmitter 1020. In addition, the wireless device 1005 may further include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0214] The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CSI reporting for short TTIs, etc.). The information may be transmitted to other components of the device. The receiver 1010 may be an example of some aspects of the transceiver 1135 described with reference to Figure 11 The receiver 1010 may use a single antenna or a set of antennas.

[0215] The base station communication manager 1015 may be an example of some aspects of the base station communication manager 1115 described with reference to Figure 11 The base station communication manager 1015 may further include a CSI manager 1025, a CSI reporter 1030, a CSI resource scheduler 1035, and a CSI resource mapper 1040.

[0216] The CSI manager 1025 may identify a first CSI reporting configuration associated with a TTI of a first duration, and identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration.

[0217] The CSI reporter 1030 may configure the wireless device to report CSI of the first CSI reporting configuration, or the second CSI reporting configuration, or both.

[0218] The CSI resource scheduler 1035 may determine a first period and a first offset for CSI reporting of the first CSI reporting configuration, and a second period and a second offset for CSI reporting of the second CSI reporting configuration. In some cases, the CSI reporting resources of the second duration are scheduled according to the second period and the second offset. In some cases, the CSI resource scheduler 1035 schedules the CSI resources for the first and / or second CSI reporting configurations on an irregular basis.

[0219] The CSI resource mapper 1040 may map the CSI resources for the second CSI reporting configuration. In some cases, the CSI resource mapper 1040 may map a first CSI reference signal resource to a first mode for the first CSI reporting configuration, and map a second CSI reference signal resource to a second mode for the second CSI reporting configuration. In some cases, the second CSI reference signal resource (which may be a CSI-RS and / or IM resource) overlaps partially or completely with the first CSI reference signal resource. In some cases, when the first CSI reference signal resource includes NZP CSI-RS and / or IM resources, the CSI resource mapper 1040 maps the second CSI reference signal resource to completely overlap with the first CSI reference signal resource. In some cases, the CSI resource scheduler 1035 schedules the TTI of the second duration, which includes the second CSI reference signal resource overlapping with the first CSI reference signal resource.

[0220] The transmitter 1020 may transmit signals generated by other components of the device. In some examples, the transmitter 1020 may be collocated with the receiver 1010 in a transceiver module. For example, the transmitter 1020 may be an example of some aspects of the transceiver 1135 described with reference to Figure 11 The transmitter 1020 may use a single antenna, or may also use a set of antennas.

[0221] Figure 11 According to aspects of the present disclosure, a block diagram of a system 1100 including a device 1105 is shown, where the device 1105 supports CSI reporting for short TTIs. The device 1105 may be, for example, as described above with reference to Figure 1The example of base station 105 described, or components including base station 105. Device 1105 may include components for two-way voice and data communication, which include components for sending communication and components for receiving communication, including base station communication manager 1115, processor 1120, memory 1125, software 1130, transceiver 1135, antenna 1140, network communication manager 1145, and inter-station communication manager 1150. These components may communicate electrically via one or more buses (e.g., bus 1110). Device 1105 may communicate wirelessly with one or more UEs 115.

[0222] Processor 1120 may include intelligent hardware devices (e.g., general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 1120 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 1120. Processor 1120 may be configured to execute computer-readable instructions stored in the memory to perform various functions (e.g., functions or tasks supporting CSI reporting for short TTI).

[0223] Memory 1125 may include RAM and ROM. Memory 1125 may store computer-readable, computer-executable software 1130 including instructions, which when executed, cause the processor to perform the various functions described herein. In some cases, specifically, memory 1125 may contain BIOS, which may control basic hardware or software operations (e.g., interaction with peripheral components or devices).

[0224] Software 1130 may include code for implementing aspects of the present disclosure, which includes code supporting CSI reporting for short TTI. Software 1130 may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, software 1130 may not be directly executed by the processor, but cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0225] Transceiver 1135 may communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, transceiver 1135 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. In addition, transceiver 1135 may also include a modem to modulate packets, provide the modulated packets to the antenna for transmission, and demodulate packets received from the antenna.

[0226] In some cases, the wireless device may include a single antenna 1140. However, in some cases, the device may have more than one antenna 1140 that are capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0227] The network communication manager 1145 may manage communication with the core network (e.g., via one or more wired backhaul links). For example, the network communication manager 1145 may manage the transmission of data communication for client devices (e.g., one or more UEs 115).

[0228] The inter-station communication manager 1150 may manage communication with other base stations 105 and may include a controller or scheduler for collaboratively controlling communication with UEs 115 with other base stations 105. For example, the inter-station communication manager 1150 may coordinate the scheduling of transmissions for UEs 115 to implement various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communication manager 1150 may provide an X2 interface in a Long Term Evolution (LTE) / LTE-Advanced wireless communication network technology to provide communication between base stations 105.

[0229] Figure 12 According to aspects of the present disclosure, a flowchart of a method 1200 for CSI reporting for short TTIs is shown. The operations of method 1200 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of method 1200 may be performed by a UE communication manager as described with reference to Figures 6 to 8 In some examples, the UE 115 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special purpose hardware to perform aspects of the functions described below.

[0230] At block 1205, the UE 115 may identify a first channel state information (CSI) report configuration associated with a TTI of a first duration. The operation of block 1205 may be performed according to the methods described herein. In certain examples, aspects of the operation of block 1205 may be performed by a CSI manager as described with reference to Figures 6 to 8 In some examples, the UE 115 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special purpose hardware to perform aspects of the functions described below.

[0231] At block 1210, the UE 115 may identify a second CSI report configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The operation of block 1210 may be performed according to the methods described herein. In certain examples, aspects of the operation of block 1210 may be performed by a CSI manager as described with reference to Figures 6 to 8 In some examples, the UE 115 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special purpose hardware to perform aspects of the functions described below.

[0232] At block 1215, the UE 115 may determine whether to report CSI for a first CSI reporting configuration, a second CSI reporting configuration, or both. The operation of block 1215 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1215 may be performed by a CSI reporter as described with reference to Figures 6 to 8 what is described.

[0233] At block 1220, the UE 115 may transmit a CSI report based on the determination. The operation of block 1220 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1220 may be performed by a transmitter as described with reference to Figures 6 to 8 what is described.

[0234] Figure 13 According to aspects of the present disclosure, a flowchart of a method 1300 for CSI reporting for short TTIs is shown. The operations of method 1300 may be implemented by the UE 115 or its components as described herein. For example, the operations of method 1300 may be performed by a UE communication manager as described with reference to Figures 6 to 8 what is described. In some examples, the UE 115 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special-purpose hardware to perform aspects of the functions described below.

[0235] At block 1305, the UE 115 may identify a first channel state information (CSI) reporting configuration associated with a TTI of a first duration. The operation of block 1305 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1305 may be performed by a CSI manager as described with reference to Figures 6 to 8 what is described.

[0236] At block 1310, the UE 115 may identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The operation of block 1310 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1310 may be performed by a CSI manager as described with reference to Figures 6 to 8 what is described.

[0237] At block 1315, the UE 115 may determine whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both. The operation of block 1315 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1315 may be performed by a CSI reporter as described with reference to Figures 6 to 8 what is described.

[0238] At block 1320, the UE 115 may identify at least one reference resource in a TTI of a second duration to determine CSI. The operation of block 1320 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1320 may be performed by a CSI resource identifier as described with reference to Figures 6 to 8 what is described.

[0239] At block 1325, the UE 115 may transmit a CSI report based on the determination. The operation of block 1325 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1325 may be performed by a transmitter as described with reference to Figures 6 to 8 what is described.

[0240] Figure 14 According to aspects of the present disclosure, a flowchart of a method 1400 for CSI reporting for short TTIs is shown. The operations of method 1400 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1400 may be performed by a UE communication manager as described with reference to Figures 6 to 8 what is described. In some examples, the UE 115 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special-purpose hardware to perform aspects of the functions described below.

[0241] At block 1405, the UE 115 may identify a first channel state information (CSI) report configuration associated with a TTI of a first duration. The operation of block 1405 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1405 may be performed by a CSI manager as described with reference to Figures 6 to 8 what is described.

[0242] At block 1410, the UE 115 may identify a second CSI report configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The operation of block 1410 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1410 may be performed by a CSI manager as described with reference to Figures 6 to 8 what is described.

[0243] At block 1415, the UE 115 may associate a first CSI process with the first CSI report configuration and associate a second CSI process with the second CSI report configuration. The operation of block 1415 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1415 may be performed by a CSI manager as described with reference to Figures 6 to 8Execute by the described CSI manager.

[0244] At block 1420, the UE 115 may determine whether to report CSI for a first CSI reporting configuration, a second CSI reporting configuration, or both. The operation of block 1420 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1420 may be performed by a CSI reporter as described with reference to Figures 6 to 8 the described CSI reporter.

[0245] At block 1425, the UE 115 may transmit a CSI report based on the determination. The operation of block 1425 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1425 may be performed by a transmitter as described with reference to Figures 6 to 8 the described transmitter.

[0246] Figure 15 According to aspects of the present disclosure, a flowchart of a method 1500 for CSI reporting for short TTIs is shown. The operations of method 1500 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of method 1500 may be performed by a UE communication manager as described with reference to Figures 6 to 8 the described UE communication manager. In some examples, the UE 115 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special-purpose hardware to perform aspects of the functions described below.

[0247] At block 1505, the UE 115 may identify a first channel state information (CSI) reporting configuration associated with a TTI of a first duration. The operation of block 1505 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1505 may be performed by a CSI manager as described with reference to Figures 6 to 8 the described CSI manager.

[0248] At block 1510, the UE 115 may identify a second CSI reporting configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The operation of block 1510 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1510 may be performed by a CSI manager as described with reference to Figures 6 to 8 the described CSI manager.

[0249] At block 1515, the UE 115 may identify a first pattern for a first NZP reference signal resource and a first interference measurement (IM) resource for a first CSI reporting configuration, where the first pattern is associated with a first period and a first offset. The operations of block 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of block 1525 may be performed by a CSI resource identifier as described with reference to Figures 6 to 8 as described.

[0250] At block 1520, the UE 115 may determine a second pattern for a second NZP reference signal resource and a second IM resource for a second CSI reporting configuration, where the second pattern is associated with a second period and a second offset. The operations of block 1530 may be performed according to the methods described herein. In some examples, aspects of the operations of block 1530 may be performed by a CSI resource identifier as described with reference to Figures 6 to 8 as described.

[0251] At block 1525, the UE 115 may determine whether to report CSI for the first CSI reporting configuration, the second CSI reporting configuration, or both. The operations of block 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of block 1515 may be performed by a CSI reporter as described with reference to Figures 6 to 8 as described.

[0252] At block 1530, the UE 115 may transmit a CSI report based on the determination. The operations of block 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of block 1520 may be performed by a transmitter as described with reference to Figures 6 to 8 as described.

[0253] Figure 16 In accordance with aspects of the present disclosure, a flowchart of a method 1600 for CSI reporting for short TTIs is shown. The operations of method 1600 may be implemented by the UE 115 or components thereof as described herein. For example, the operations of method 1600 may be performed by a UE communication manager as described with reference to Figures 6 to 8 as described. In some examples, the UE 115 may execute a set of code to control the functional units of the device to perform the functions described below. Additionally or alternatively, the UE 115 may use special-purpose hardware to perform aspects of the functions described below.

[0254] At block 1605, the UE 115 may identify a first channel state information (CSI) report configuration associated with a transmission time interval (TTI) of a first duration. The operation of block 1605 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1605 may be performed by a CSI manager as described with reference to Figures 6 to 8 as described.

[0255] At block 1610, the UE 115 may identify a second CSI report configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The operation of block 1610 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1610 may be performed by a CSI manager as described with reference to Figures 6 to 8 as described.

[0256] At block 1615, the UE 115 may identify a first pattern of a first non-zero power (NZP) reference signal resource and a first interference measurement (IM) resource for the first CSI report configuration, where the first pattern is associated with a first period and a first offset. The operation of block 1620 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1620 may be performed by a CSI resource identifier as described with reference to Figures 6 to 8 as described.

[0257] At block 1620, the UE 115 may receive an indication that one or more NZP reference signal resources and one or more IM resources for the second CSI report configuration are present in the TTI of the first duration, where the TTI of the first duration includes a subset of the first NZP reference signal resources of the first pattern and a subset of the first IM resources. The operation of block 1625 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1625 may be performed by a CSI resource identifier as described with reference to Figures 6 to 8 as described.

[0258] At block 1625, the UE 115 may determine whether to report CSI for the first CSI report configuration, the second CSI report configuration, or both. The operation of block 1615 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1615 may be performed by a CSI reporter as described with reference to Figures 6 to 8 as described.

[0259] At block 1630, the UE 115 may transmit a CSI report based on the determination. The operation of block 1630 may be performed according to the methods described herein. In some examples, aspects of the operation of block 1630 may be performed by a component as described with reference to Figures 6 to 8performed by the described transmitter.

[0260] Figure 17 According to aspects of the present disclosure, a flowchart of a method 1700 for CSI reporting for short TTIs is shown. Operations of method 1700 may be implemented by a base station 105 or its components as described herein. For example, operations of method 1700 may be performed by a base station communication manager as described with reference to Figures 9 to 11 the described one. In some examples, the base station 105 may execute a set of codes to control the functional units of the device to perform the functions described below. Additionally or alternatively, the base station 105 may use special-purpose hardware to perform aspects of the functions described below.

[0261] At block 1705, the base station 105 may identify a first channel state information (CSI) report configuration associated with a TTI of a first duration. The operation of block 1705 may be performed according to the methods described herein. In certain examples, aspects of the operation of block 1705 may be performed by a CSI manager as described with reference to Figures 9 to 11 the described one.

[0262] At block 1710, the base station 105 may identify a second CSI report configuration associated with a TTI of a second duration, where the second duration is shorter than the first duration. The operation of block 1710 may be performed according to the methods described herein. In certain examples, aspects of the operation of block 1710 may be performed by a CSI manager as described with reference to Figures 9 to 11 the described one.

[0263] At block 1715, the base station 105 may configure whether the wireless device reports CSI of the first CSI report configuration, or the second CSI report configuration, or both. The operation of block 1715 may be performed according to the methods described herein. In certain examples, aspects of the operation of block 1715 may be performed by a CSI reporter as described with reference to Figures 9 to 11 the described one.

[0264] At block 1720, the base station 105 may transmit a CSI report based on the determination. The operation of block 1720 may be performed according to the methods described herein. In certain examples, aspects of the operation of block 1720 may be performed by a transmitter as described with reference to Figures 9 to 11 the described one.

[0265] It should be noted that the methods described above describe some possible implementations, and these operations and steps may be rearranged or modified, and other implementations are possible. In addition, aspects from two or more of these methods may be combined.

[0266] The techniques described herein can be used in various wireless communication systems, such as, Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-Carrier Frequency Division Multiple Access (SC-FDMA), and other systems. CDMA systems can implement wireless technologies such as CDMA 2000, Universal Terrestrial Radio Access (UTRA), and so on. CDMA2000 covers the IS-2000, IS-95, and IS-856 standards. The Release of IS-2000 is commonly referred to as CDMA 2000 1X, 1X, and so on. IS-856 (TIA-856) is commonly referred to as CDMA 2000 1xEV-DO, High Rate Packet Data (HRPD), and so on. UTRA includes Wideband CDMA (WCDMA) and other CDMA variants. TDMA systems can implement wireless technologies such as Global System for Mobile Communications (GSM).

[0267] OFDMA systems can implement wireless technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and so on. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are new versions of UMTS that employ E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, NR, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used in the systems and wireless technologies mentioned above and other systems and wireless technologies. Although aspects of the LTE or NR systems are described for illustrative purposes and the LTE or NR terminology is used in most of the description, the techniques described herein are also applicable outside of LTE or NR applications.

[0268] Macro cells typically cover a relatively large geographical area (e.g., with a radius of several kilometers), which allows unrestricted access for UEs 115 having a service subscription with the network provider. Compared with macro cells, small cells can be associated with low-power base stations 105 and can operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. According to various examples, small cells can include pico cells, femto cells, and micro cells. For example, a pico cell can cover a relatively small geographical area, which allows unrestricted access for UEs 115 having a service subscription with the network provider. In addition, a femto cell can also cover a small geographical area (e.g., a home), which can provide restricted access to UEs 115 associated with the femto cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 for users in a home, etc.). The eNB for a macro cell can be referred to as a macro eNB. The eNB for a small cell can be referred to as a small cell eNB, pico eNB, femto eNB, or home eNB. An eNB can support one or more (e.g., two, three, four, etc.) cells and can also support communication using one or more component carriers.

[0269] The wireless communication system 100 described herein or some systems can support synchronous or asynchronous operations. For synchronous operations, the base stations 105 can have similar frame timings, and transmissions from different base stations 105 are approximately aligned in time. For asynchronous operations, the base stations 105 can have different frame timings, and transmissions from different base stations 105 are not aligned in time. The techniques described herein can be used for synchronous operations and can also be used for asynchronous operations.

[0270] The information and signals described herein can be represented using any of a variety of different technologies and methods. For example, the data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0271] A general-purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device (PLD), discrete gate or transistor logic device, discrete hardware component, or any combination thereof for performing the functions described herein can be used to implement or execute the various exemplary blocks and modules described in connection with the disclosure herein. The general-purpose processor can be a microprocessor, or alternatively, the processor can be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, several microprocessors, a combination of a microprocessor and a DSP core, or any other such configuration).

[0272] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions can be stored on a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Other examples and implementations also fall within the scope of the present disclosure and its appended claims. For example, due to the nature of software, the functions described above can be implemented using software, hardware, firmware, hardwiring, or any combination thereof executed by a processor. The features for implementing the functions can be physically distributed in multiple locations, including being distributed in different physical locations to implement a part of the functions.

[0273] Computer-readable media includes non-transitory computer storage media and communication media, where the communication media includes any medium that facilitates transfer of a computer program from one place to another. The non-transitory storage media can be any available media that can be accessed by a general or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), flash memory, compact disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code units in the form of instructions or data structures and that can be accessed by a general or special purpose computer, or a general or special purpose processor. Additionally, any connection can be properly termed a computer-readable medium. By way of example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically, while discs optically reproduce data with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0274] As used herein (which includes the claims), the "or" as used in a list item (e.g., a list item ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such that, for example, at least one of A, B, or C means: A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Additionally, as used herein, the phrase "based on" should not be construed as referring to a closed set of conditions. For example, an exemplary step described as "based on condition A" may be based on condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "at least partially based on".

[0275] In the drawings, like parts or features have the same reference numerals. Additionally, each of the same type of parts may be distinguished by adding a dashed line after the reference numeral and a second label for differentiating similar parts. If only the first reference numeral is used in the specification, the description may apply to any one of the similar parts having the same first reference numeral, regardless of other subsequent reference numerals.

[0276] The specific embodiments described herein in conjunction with the drawings describe exemplary configurations, but they do not represent all examples that can be implemented, nor all examples that fall within the scope of the claims. As used herein, the term "exemplary" means "serving as an example, illustration, or instance", but does not mean "more preferred" or "more advantageous" than other examples. The specific embodiments include specific details for providing a thorough understanding of the described technologies. However, these technologies can be implemented without using these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0277] The foregoing has been described around the present disclosure to enable any ordinary person skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure are obvious to those of ordinary skill in the art, and the general principles defined herein can also be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is consistent with the broadest scope of the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a wireless device, comprising: Receiving, from a base station, a first channel state information (CSI) report configuration and a second CSI report configuration, wherein the first CSI report configuration is associated with a transmission time interval (TTI) for a first duration of a CSI report resource, and the second CSI report configuration is associated with a TTI for a second duration of a CSI report resource; Determining a CSI report based on one of the first CSI report configuration and the second CSI report configuration; and Transmitting the determined CSI report.

2. The method according to claim 1, further comprising: Identifying a first CSI resource for the first CSI report configuration, or Identifying a second CSI resource for the second CSI report configuration; Wherein the first CSI resource has a first resource TTI, and the second CSI resource has a second resource TTI.

3. The method according to claim 2, wherein The first CSI resource and the second CSI resource have different periods.

4. The method according to claim 1, further comprising: Receiving a trigger for a CSI report for the first CSI report configuration.

5. The method according to claim 4, wherein The CSI report for the second CSI report configuration is triggered separately from the first CSI report configuration.

6. The method according to claim 2, wherein The first CSI resource or the second CSI resource includes a plurality of reference symbol occasions having 14 symbol periods.

7. The method according to claim 6, wherein The plurality of reference symbol occasions having 14 symbol periods includes one reference symbol occasion for a CSI-reference signal (CSI-RS) and one reference symbol occasion for interference measurement.

8. The method according to claim 1, wherein the first CSI report configuration and the second CSI report configuration are associated with different maximum CSI processes.

9. An apparatus for wireless communication, comprising: A processor; A memory coupled to the processor; And Instructions stored in the memory, which when executed by the processor, are operable to cause the apparatus to perform the following operations: Receiving, from a base station, a first channel state information (CSI) report configuration and a second CSI report configuration, wherein the first CSI report configuration is associated with a transmission time interval (TTI) for a first duration of a CSI report resource, and The second CSI report configuration is associated with a TTI for a second duration of a CSI report resource; Determining a CSI report based on one of the first CSI report configuration and the second CSI report configuration; And Transmitting the determined CSI report.

10. The apparatus according to claim 9, wherein The instructions can be further executed by the processor for: Identifying a first CSI resource for the first CSI report configuration, or Identifying a second CSI resource for the second CSI report configuration; Wherein the first CSI resource has a first resource TTI, and the second CSI resource has a second resource TTI.

11. The apparatus according to claim 10, wherein, The first CSI resource and the second CSI resource have different periods.

12. The apparatus according to claim 9, wherein, The instructions can be further executed by the processor for: Receive a trigger for a CSI report for the first CSI report configuration.

13. The apparatus according to claim 12, wherein, The CSI report for the second CSI report configuration is triggered separately from the first CSI report configuration.

14. The apparatus according to claim 10, wherein, The first CSI resource or the second CSI resource includes a plurality of reference symbol occasions having 14 symbol periods.

15. The apparatus according to claim 14, wherein, The plurality of reference symbol occasions having 14 symbol periods includes one reference symbol occasion for a CSI-reference signal (CSI-RS) and one reference symbol occasion for interference measurement.

16. The apparatus according to claim 9, wherein the first CSI report configuration and the second CSI report configuration are associated with different maximum CSI processes.

17. A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform the following operations: Receiving a first channel state information (CSI) report configuration and a second CSI report configuration from a base station, where The first CSI report configuration is associated with a transmission time interval (TTI) for a first duration of a CSI report resource, and the second CSI report configuration is associated with a TTI for a second duration of a CSI report resource; Determine a CSI report based on one of the first CSI report configuration and the second CSI report configuration; And Transmit the determined CSI report.

18. The non-transitory computer-readable medium according to claim 17, wherein, The instructions may further be executable by the processor for: Identifying a first CSI resource for the first CSI report configuration, or Identifying a second CSI resource for the second CSI report configuration; Wherein the first CSI resource has a first resource TTI and the second CSI resource has a second resource TTI.

19. The non-transitory computer-readable medium according to claim 18, wherein, The first CSI resource and the second CSI resource have different periods.

20. The non-transitory computer-readable medium according to claim 17, wherein, The instructions may further be executable by the processor for: Receive a trigger for a CSI report for the first CSI report configuration.

21. The non-transitory computer-readable medium according to claim 20, wherein, The CSI report for the second CSI report configuration is triggered separately from the first CSI report configuration.

22. The non-transitory computer-readable medium according to claim 18, wherein, The first CSI resource or the second CSI resource includes a plurality of reference symbol occasions having 14 symbol periods.

23. The non-transitory computer-readable medium according to claim 22, wherein, The plurality of reference symbol occasions having 14 symbol periods includes one reference symbol occasion for a CSI-reference signal (CSI-RS) and one reference symbol occasion for interference measurement.

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