Differential measurement reporting based on a demodulation reference signal

A method of wireless communication includes receiving, by a user equipment (UE), a first transmission and transmitting, by the UE, a first measurement report that is based on the first transmission and includes at least a first measurement result. The method further includes receiving, by the UE, a second transmission that includes a demodulation reference signal (DMRS) and further includes transmitting, by the UE, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to wireless communication systems that perform measurement reporting.

DESCRIPTION OF THE RELATED TECHNOLOGY

SUMMARY

In some aspects of the disclosure, a method of wireless communication includes receiving, by a user equipment (UE), a first transmission and transmitting, by the UE, a first measurement report that is based on the first transmission and includes at least a first measurement result. The method further includes receiving, by the UE, a second transmission that includes a demodulation reference signal (DMRS) and further includes transmitting, by the UE, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In some other aspects of the disclosure, an apparatus for wireless communication includes a receiver configured to receive a first transmission and to receive a second transmission that includes a DMRS. The apparatus further includes a transmitter configured to transmit a first measurement report that is based on the first transmission and that includes at least a first measurement result and to transmit a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In some other aspects of the disclosure, a method of wireless communication includes transmitting, by a base station, a first transmission and receiving, by the base station, a first measurement report that is based on the first transmission and includes at least a first measurement result. The method further includes transmitting, by the base station, a second transmission that includes a DMRS and receiving, by the base station, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In some other examples, an apparatus for wireless communication includes a transmitter configured to transmit a first transmission and to transmit a second transmission that includes a DMRS. The apparatus further includes a receiver configured to receive a first measurement report that is based on the first transmission and includes at least a first measurement result and to receive a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

DETAILED DESCRIPTION

Wireless communications systems increasingly provide premium services and other features. For example, cellular phones may provide broadband communications, low latency, high reliability, high throughput, and other services. As a result, wireless communication systems include features such as embedded mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and vehicle-to-everything (V2X) communications.

In some applications, such features may increase overhead and complexity, which may decrease certain performance parameters or cost-efficiency. For example, some “low-overhead” devices (such as a stationary sensor or a stationary camera) may occasionally transmit a relatively small amount of data to a network device. If the network device supports low latency, high reliability, and high throughput, then power consumption of the devices may be increased, which may reduce battery life or increase operation complexity of the metering devices in some cases.

A wireless communication system in accordance with some aspects of the disclosure may use differential measurement reporting to reduce an amount of data transmitted in the wireless communication system. To illustrate, a user equipment (UE) may perform measurements based on a demodulation reference signal (DMRS) that may have a quasi-colocation (QCL) relation with a prior signal, such as a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). The UE may indicate the measurements to a base station in a differential format, such as by indicating values that correspond to a difference between the measurements and other measurements of a prior measurement report transmitted based on the prior signal. In such examples, the values may be referred to as being reported on a time-differential or inter-report basis. Alternatively or in addition, measurements may be reported on an intra-report basis. In such examples, a value of a measurement report may correspond to a difference between multiple measurements associated with the measurement report.

By using a differential format to report measurements, an amount of data transmitted via a wireless communication system may be reduced, which may be advantageous in some applications, such as low-overhead wireless communication protocols. To illustrate, in some wireless communication protocols, measurements may be reported using a relatively large number of bits or digits, and the measurements may change relatively infrequently (such as in the case of stationary sensors in a building, as an illustrative example). Further, in some cases, a DMRS may serve multiple purposes in a wireless communication system, which may reduce a number of reference signals or a number of resources associated with reference signals in the wireless communication system. For example, in addition to using a DMRS to estimate channel characteristics and demodulate signals received from a base station, a UE may report measurements based on the DMRS. As a result, one or more of a periodicity of a CSI-RS or an SSB or a number of resources used to transmit the CSI-RS or the SSB may be reduced, increasing bandwidth or resources available for other communications, for other devices, or both.

Devices, networks, and systems may be configured to communicate via one or more portions of the electromagnetic spectrum. The electromagnetic spectrum is often subdivided, based on frequency or wavelength, into various classes, bands, channels, etc. In 5G NR two initial operating bands have been identified as frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” (mmWave) band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz-300 GHz) which is identified by the International Telecommunications Union (ITU) as a “mmWave” band.

FIG. 1is a block diagram illustrating 5G network100including various base stations and UEs configured according to aspects of the present disclosure. The 5G network100includes a number of base stations105and other network entities. A base station may be a station that communicates with the UEs and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each base station105may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a base station and/or a base station subsystem serving the coverage area, depending on the context in which the term is used.

The 5G network100may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time.

The UEs115are dispersed throughout the wireless network100, and each UE may be stationary or mobile. A UE may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE may be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE may be a device that does not include a UICC. In some aspects, UEs that do not include UICCs may also be referred to as internet of everything (IoE) or internet of things (IoT) devices. UEs115a-115dare examples of mobile smart phone-type devices accessing 5G network100A UE may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs115e-115kare examples of various machines configured for communication that access 5G network100. A UE may be able to communicate with any type of the base stations, whether macro base station, small cell, or the like. InFIG. 1, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE and a serving base station, which is a base station designated to serve the UE on the downlink and/or uplink, or desired transmission between base stations, and backhaul transmissions between base stations.

FIG. 2shows a block diagram of a design of a base station105and a UE115, which may be one of the base station and one of the UEs inFIG. 1. At the base station105, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor220may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor230may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)232athrough232t. Each modulator232may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators232athrough232tmay be transmitted via the antennas234athrough234t, respectively.

At the UE115, the antennas252athrough252rmay receive the downlink signals from the base station105and may provide received signals to the demodulators (DEMODs)254athrough254r, respectively. Each demodulator254may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator254may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector256may obtain received symbols from all the demodulators254athrough254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor258may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE115to a data sink260, and provide decoded control information to a controller/processor280.

On the uplink, at the UE115, a transmit processor264may receive and process data (e.g., for the PUSCH) from a data source262and control information (e.g., for the PUCCH) from the controller/processor280. The transmit processor264may also generate reference symbols for a reference signal. The symbols from the transmit processor264may be precoded by a TX MIMO processor266if applicable, further processed by the modulators254athrough254r(e.g., for SC-FDM, etc.), and transmitted to the base station105. At the base station105, the uplink signals from the UE115may be received by the antennas234, processed by the demodulators232, detected by a MIMO detector236if applicable, and further processed by a receive processor238to obtain decoded data and control information sent by the UE115. The processor238may provide the decoded data to a data sink239and the decoded control information to the controller/processor240.

The controllers/processors240and280may direct the operation at the base station105and the UE115, respectively. The controller/processor240and/or other processors and modules at the base station105may perform or direct the execution of various processes for the techniques described herein. The controllers/processor280and/or other processors and modules at the UE115may also perform or direct the execution of the functional blocks illustrated inFIGS. 7 and 8and/or other processes for the techniques described herein. The memories242and282may store data and program codes for the base station105and the UE115, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

Wireless communications systems operated by different network operating entities (e.g., network operators) may share spectrum. In some instances, a network operating entity may be configured to use an entirety of a designated shared spectrum for at least a period of time before another network operating entity uses the entirety of the designated shared spectrum for a different period of time. Thus, in order to allow network operating entities use of the full designated shared spectrum, and in order to mitigate interfering communications between the different network operating entities, certain resources (e.g., time) may be partitioned and allocated to the different network operating entities for certain types of communication.

For example, a network operating entity may be allocated certain time resources reserved for exclusive communication by the network operating entity using the entirety of the shared spectrum. The network operating entity may also be allocated other time resources where the entity is given priority over other network operating entities to communicate using the shared spectrum. These time resources, prioritized for use by the network operating entity, may be utilized by other network operating entities on an opportunistic basis if the prioritized network operating entity does not utilize the resources. Additional time resources may be allocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resources among different network operating entities may be centrally controlled by a separate entity, autonomously determined by a predefined arbitration scheme, or dynamically determined based on interactions between wireless nodes of the network operators.

In general, four categories of LBT procedure have been suggested for sensing a shared channel for signals that may indicate the channel is already occupied. In a first category (CAT 1 LBT), no LBT or CCA is applied to detect occupancy of the shared channel. A second category (CAT 2 LBT), which may also be referred to as an abbreviated LBT, a single-shot LBT, or a 25-μs LBT, provides for the node to perform a CCA to detect energy above a predetermined threshold or detect a message or preamble occupying the shared channel. The CAT 2 LBT performs the CCA without using a random back-off operation, which results in its abbreviated length, relative to the next categories.

A third category (CAT 3 LBT) performs CCA to detect energy or messages on a shared channel, but also uses a random back-off and fixed contention window. Therefore, when the node initiates the CAT 3 LBT, it performs a first CCA to detect occupancy of the shared channel. If the shared channel is idle for the duration of the first CCA, the node may proceed to transmit. However, if the first CCA detects a signal occupying the shared channel, the node selects a random back-off based on the fixed contention window size and performs an extended CCA. If the shared channel is detected to be idle during the extended CCA and the random number has been decremented to 0, then the node may begin transmission on the shared channel. Otherwise, the node decrements the random number and performs another extended CCA. The node would continue performing extended CCA until the random number reaches 0. If the random number reaches 0 without any of the extended CCAs detecting channel occupancy, the node may then transmit on the shared channel. If at any of the extended CCA, the node detects channel occupancy, the node may re-select a new random back-off based on the fixed contention window size to begin the countdown again.

A fourth category (CAT 4 LBT), which may also be referred to as a full LBT procedure, performs the CCA with energy or message detection using a random back-off and variable contention window size. The sequence of CCA detection proceeds similarly to the process of the CAT 3 LBT, except that the contention window size is variable for the CAT 4 LBT procedure.

Use of a medium-sensing procedure to contend for access to an unlicensed shared spectrum may result in communication inefficiencies. This may be particularly evident when multiple network operating entities (e.g., network operators) are attempting to access a shared resource. In the 5G network100, base stations105and UEs115may be operated by the same or different network operating entities. In some examples, an individual base station105or UE115may be operated by more than one network operating entity. In other examples, each base station105and UE115may be operated by a single network operating entity. Requiring each base station105and UE115of different network operating entities to contend for shared resources may result in increased signaling overhead and communication latency.

FIG. 3illustrates an example of a timing diagram300for coordinated resource partitioning. The timing diagram300includes a superframe305, which may represent a fixed duration of time (e.g., 20 ms). The superframe305may be repeated for a given communication session and may be used by a wireless system such as 5G network100described with reference toFIG. 1. The superframe305may be divided into intervals such as an acquisition interval (A-INT)310and an arbitration interval315. As described in more detail below, the A-INT310and arbitration interval315may be subdivided into sub-intervals, designated for certain resource types, and allocated to different network operating entities to facilitate coordinated communications between the different network operating entities. For example, the arbitration interval315may be divided into a plurality of sub-intervals320. Also, the superframe305may be further divided into a plurality of subframes325with a fixed duration (e.g., 1 ms). While timing diagram300illustrates three different network operating entities (e.g., Operator A, Operator B, Operator C), the number of network operating entities using the superframe305for coordinated communications may be greater than or fewer than the number illustrated in timing diagram300.

The A-INT310may be a dedicated interval of the superframe305that is reserved for exclusive communications by the network operating entities. In some examples, each network operating entity may be allocated certain resources within the A-INT310for exclusive communications. For example, resources330-amay be reserved for exclusive communications by Operator A, such as through base station105a, resources330-bmay be reserved for exclusive communications by Operator B, such as through base station105b, and resources330-cmay be reserved for exclusive communications by Operator C, such as through base station105c. Since the resources330-aare reserved for exclusive communications by Operator A, neither Operator B nor Operator C can communicate during resources330-a, even if Operator A chooses not to communicate during those resources. That is, access to exclusive resources is limited to the designated network operator. Similar restrictions apply to resources330-bfor Operator B and resources330-cfor Operator C. The wireless nodes of Operator A (e.g., UEs115or base stations105) may communicate any information desired during their exclusive resources330-a, such as control information or data.

When communicating over an exclusive resource, a network operating entity does not need to perform any medium sensing procedures (e.g., listen-before-talk (LBT) or clear channel assessment (CCA)) because the network operating entity knows that the resources are reserved. Because only the designated network operating entity may communicate over exclusive resources, there may be a reduced likelihood of interfering communications as compared to relying on medium sensing techniques alone (e.g., no hidden node problem). In some examples, the A-INT310is used to transmit control information, such as synchronization signals (e.g., SYNC signals), system information (e.g., system information blocks (SIBs)), paging information (e.g., physical broadcast channel (PBCH) messages), or random access information (e.g., random access channel (RACH) signals). In some examples, all of the wireless nodes associated with a network operating entity may transmit at the same time during their exclusive resources.

In some examples, resources may be classified as prioritized for certain network operating entities. Resources that are assigned with priority for a certain network operating entity may be referred to as a guaranteed interval (G-INT) for that network operating entity. The interval of resources used by the network operating entity during the G-INT may be referred to as a prioritized sub-interval. For example, resources335-amay be prioritized for use by Operator A and may therefore be referred to as a G-INT for Operator A (e.g., G-INT-OpA). Similarly, resources335-bmay be prioritized for Operator B, (e.g., G-INT-OpB), resources335-c(e.g., G-INT-OpC) may be prioritized for Operator C, resources335-dmay be prioritized for Operator A, resources335-emay be prioritized for Operator B, and resources335-fmay be prioritized for Operator C.

The various G-INT resources illustrated inFIG. 3appear to be staggered to illustrate their association with their respective network operating entities, but these resources may all be on the same frequency bandwidth. Thus, if viewed along a time-frequency grid, the G-INT resources may appear as a contiguous line within the superframe305. This partitioning of data may be an example of time division multiplexing (TDM). Also, when resources appear in the same sub-interval (e.g., resources340-aand resources335-b), these resources represent the same time resources with respect to the superframe305(e.g., the resources occupy the same sub-interval320), but the resources are separately designated to illustrate that the same time resources can be classified differently for different operators.

When resources are assigned with priority for a certain network operating entity (e.g., a G-INT), that network operating entity may communicate using those resources without having to wait or perform any medium sensing procedures (e.g., LBT or CCA). For example, the wireless nodes of Operator A are free to communicate any data or control information during resources335-awithout interference from the wireless nodes of Operator B or Operator C.

A network operating entity may additionally signal to another operator that it intends to use a particular G-INT. For example, referring to resources335-a, Operator A may signal to Operator B and Operator C that it intends to use resources335-a. Such signaling may be referred to as an activity indication. Moreover, since Operator A has priority over resources335-a, Operator A may be considered as a higher priority operator than both Operator B and Operator C. However, as discussed above, Operator A does not have to send signaling to the other network operating entities to ensure interference-free transmission during resources335-abecause the resources335-aare assigned with priority to Operator A.

Similarly, a network operating entity may signal to another network operating entity that it intends not to use a particular G-INT. This signaling may also be referred to as an activity indication. For example, referring to resources335-b, Operator B may signal to Operator A and Operator C that it intends not to use the resources335-bfor communication, even though the resources are assigned with priority to Operator B. With reference to resources335-b, Operator B may be considered a higher priority network operating entity than Operator A and Operator C. In such cases, Operators A and C may attempt to use resources of sub-interval320on an opportunistic basis. Thus, from the perspective of Operator A, the sub-interval320that contains resources335-bmay be considered an opportunistic interval (O-INT) for Operator A (e.g., O-INT-OpA). For illustrative purposes, resources340-amay represent the O-INT for Operator A. Also, from the perspective of Operator C, the same sub-interval320may represent an O-INT for Operator C with corresponding resources340-b. Resources340-a,335-b, and340-ball represent the same time resources (e.g., a particular sub-interval320), but are identified separately to signify that the same resources may be considered as a G-INT for some network operating entities and yet as an O-INT for others.

To utilize resources on an opportunistic basis, Operator A and Operator C may perform medium-sensing procedures to check for communications on a particular channel before transmitting data. For example, if Operator B decides not to use resources335-b(e.g., G-INT-OpB), then Operator A may use those same resources (e.g., represented by resources340-a) by first checking the channel for interference (e.g., LBT) and then transmitting data if the channel was determined to be clear. Similarly, if Operator C wanted to access resources on an opportunistic basis during sub-interval320(e.g., use an O-INT represented by resources340-b) in response to an indication that Operator B was not going to use its G-INT (e.g., resources335-b), Operator C may perform a medium sensing procedure and access the resources if available. In some cases, two operators (e.g., Operator A and Operator C) may attempt to access the same resources, in which case the operators may employ contention-based procedures to avoid interfering communications. The operators may also have sub-priorities assigned to them designed to determine which operator may gain access to resources if more than operator is attempting access simultaneously. For example, Operator A may have priority over Operator C during sub-interval320when Operator B is not using resources335-b(e.g., G-INT-OpB). It is noted that in another sub-interval (not shown) Operator C may have priority over Operator A when Operator B is not using its G-INT.

In some examples, a network operating entity may intend not to use a particular G-INT assigned to it, but may not send out an activity indication that conveys the intent not to use the resources. In such cases, for a particular sub-interval320, lower priority operating entities may be configured to monitor the channel to determine whether a higher priority operating entity is using the resources. If a lower priority operating entity determines through LBT or similar method that a higher priority operating entity is not going to use its G-INT resources, then the lower priority operating entities may attempt to access the resources on an opportunistic basis as described above.

In some examples, access to a G-INT or O-INT may be preceded by a reservation signal (e.g., request-to-send (RTS)/clear-to-send (CTS)), and the contention window (CW) may be randomly chosen between one and the total number of operating entities.

In some examples, an operating entity may employ or be compatible with coordinated multipoint (CoMP) communications. For example an operating entity may employ CoMP and dynamic time division duplex (TDD) in a G-INT and opportunistic CoMP in an O-INT as needed.

In the example illustrated inFIG. 3, each sub-interval320includes a G-INT for one of Operator A, B, or C. However, in some cases, one or more sub-intervals320may include resources that are neither reserved for exclusive use nor reserved for prioritized use (e.g., unassigned resources). Such unassigned resources may be considered an O-INT for any network operating entity, and may be accessed on an opportunistic basis as described above.

In some examples, each subframe325may contain 14 symbols (e.g., 250-μs for 60 kHz tone spacing). These subframes325may be standalone, self-contained Interval-Cs (ITCs) or the subframes325may be a part of a long ITC. An ITC may be a self-contained transmission starting with a downlink transmission and ending with an uplink transmission. In some embodiments, an ITC may contain one or more subframes325operating contiguously upon medium occupation. In some cases, there may be a maximum of eight network operators in an A-INT310(e.g., with duration of 2 ms) assuming a 250-μs transmission opportunity.

Although three operators are illustrated inFIG. 3, it should be understood that fewer or more network operating entities may be configured to operate in a coordinated manner as described above. In some cases, the location of the G-INT, O-INT, or A-INT within the superframe305for each operator is determined autonomously based on the number of network operating entities active in a system. For example, if there is only one network operating entity, each sub-interval320may be occupied by a G-INT for that single network operating entity, or the sub-intervals320may alternate between G-INTs for that network operating entity and O-INTs to allow other network operating entities to enter. If there are two network operating entities, the sub-intervals320may alternate between G-INTs for the first network operating entity and G-INTs for the second network operating entity. If there are three network operating entities, the G-INT and O-INTs for each network operating entity may be designed as illustrated inFIG. 3. If there are four network operating entities, the first four sub-intervals320may include consecutive G-INTs for the four network operating entities and the remaining two sub-intervals320may contain O-INTs. Similarly, if there are five network operating entities, the first five sub-intervals320may contain consecutive G-INTs for the five network operating entities and the remaining sub-interval320may contain an O-INT. If there are six network operating entities, all six sub-intervals320may include consecutive G-INTs for each network operating entity. It should be understood that these examples are for illustrative purposes only and that other autonomously determined interval allocations may be used.

It should be understood that the coordination framework described with reference toFIG. 3is for illustration purposes only. For example, the duration of superframe305may be more or less than 20 ms. Also, the number, duration, and location of sub-intervals320and subframes325may differ from the configuration illustrated. Also, the types of resource designations (e.g., exclusive, prioritized, unassigned) may differ or include more or less sub-designations.

FIG. 4is a block diagram illustrating an example of a wireless communication system400according to some aspects of the disclosure. The wireless communication system400may include one or more base stations, such as the base station105, and may include one or more UEs, such as the UE115.

The base station105may include one or more processors (such as the controller/processor240), one or more memories (such as the memory242), a transmitter480, and a receiver484. The transmitter480and the receiver484may include one or more components or devices described herein, such as the modulator/demodulators232a-t, the MIMO detector236, the receive processor238, the transmit processor220, the TX MIMO processor230, one or more other components or devices, or a combination thereof.

The UE115may include one or more processors (such as the controller/processor280), one or more memories (such as the memory282), a transmitter490, and a receiver492. The transmitter490and the receiver492may include one or more components or devices described herein, such as the modulator/demodulators254a-r, the MIMO detector256, the receive processor258, the transmit processor264, the TX MIMO processor266, one or more other components or devices, or a combination thereof.

In some aspects, the wireless communications system400includes or corresponds to a low power wide area (LPWA) network. For example, the wireless communications system400may correspond to a reduced capability (RedCap) network that includes one or more UEs115having performance parameters (such as peak throughput, latency, and reliability) that are less than (or “relaxed”) as compared to performance parameters of other devices, such as a device that supports eMBB or URLLC features. To further illustrate, in some examples, the UE115corresponds to “light” or “superlight” device that uses low-power or low-complexity operations as compared to a device that supports eMBB or URLLC features.

During operation, the UE115may perform measurements and may report the measurements to the base station105. To illustrate, the base station105may perform a first transmission410. Depending on the particular example, the first transmission410may include a synchronization signal block (SSB)412, a channel state information reference signal (CSI-RS)414, or a demodulation reference signal (DMRS)416, one or more other signals, or a combination thereof. The UE115may perform measurements based on the first transmission410to generate first measurement results450. To illustrate, the base station105may transmit the first transmission410using a set of beams, and the UE115may perform a beam sweeping operation to measure one or more parameters (such as a signal-to-interference-plus-noise ratio (SINR) or a received signal strength indicator (RSSI)) for each beam of the set of beams. The first measurement results450may include the measured parameters, and the UE115may report the measured parameters to the base station105using a first measurement report420that is based on the first transmission410.

After the first transmission410, the base station105may perform a second transmission430that includes a DMRS432. The UE115may perform measurements based on the second transmission430to generate second measurement results460. In some examples, the UE115may perform one or more operations described with reference to the first measurement results450and the first transmission410to generate the second measurement results460. For example, the base station105may transmit the second transmission430using the same set of beams described with reference to the first transmission410. The UE115may perform a beam sweeping operation to measure one or more parameters (such as an SINR or an RSSI) for each beam of the set of beams. The second measurement results460may include the measured parameters, and the UE115may report the measured parameters to the base station105using a second measurement report440that is based on the DMRS432.

In some aspects of the disclosure, the second measurement report440includes one or more values that are differential with respect to one or more values of the first measurement report420. To illustrate, the first measurement report420may indicate a first measurement result422of the first measurement results450, and the second measurement report440may include a first value442that corresponds to or that is based on a difference424between the first measurement result422and a second measurement result462of the second measurement results460. The first value442may include fewer bits than the second measurement result462, such as if the second measurement result462is similar to or the same as the first measurement result422(e.g., where channel conditions associated with the wireless communication system400are relatively invariant). In such examples, a data size of the second measurement report440may be reduced as compared to some other examples in which the second transmission430includes an explicit indication of the second measurement result462.

The first value442may be referred to as a time-differential value or as an inter-report differential value. Alternatively or in addition, one or more values of the second measurement report440may be indicated on an intra-report differential basis. To illustrate, the second measurement report440may further include a second value444that corresponds to or is based on a difference466between the second measurement result462and a third measurement result464of the second measurement results460. In such examples, the second measurement report440may indicate the third measurement result464on intra-report differential basis (because the second value444may correspond to or may be based on the difference466between the measurement results462,464of the second measurement results460). Further, in such examples, the second measurement report440may include at least one value that is indicated on an inter-report basis (such as the first value442) and may include at least one other value that is indicated on an intra-report basis (such as the second value444).

In some other examples, one or more other values of the second measurement report440(in addition to the first value442) may be indicated on an inter-report basis. For example, in some implementations, the second value444may correspond to or may be based on a difference468between the first measurement result422and the third measurement result464. In some examples, each value of the second measurement report440may be indicated on an inter-report basis (e.g., with respect to the first measurement report420).

One or more aspects described herein may be configured by the base station105, by one or more other network devices, or a combination thereof. To illustrate, the base station105may transmit to the UE115one or more configuration messages402associated with DMRS-based measurement reporting. In some examples, the one or more configuration messages402have a radio resource control (RRC) format.

FIG. 4illustrates that the one or more configuration messages402may include a quasi-colocation (QCL) indicator404that indicates that the first transmission410has a QCL relation with the second transmission430. In some examples, the QCL relation indicates that the first transmission410and the second transmission430have one or more common properties, such as one or more of a common transmit beam, a common Doppler shift, a common Doppler spread, a common average delay, a common average delay spread, or a common spatial receive parameter, as illustrative examples. In some examples, the QCL indicator404includes or corresponds to a flag in a transmission configuration indicator (TCI) state indicated by the one or more configuration messages402.

In some examples, the QCL indicator404indicates that the first transmission410and the second transmission430are associated with a same spatial transmit filter482. The base station105may use the same spatial transmit filter482to perform the first transmission410and the second transmission430. Further, in some examples, the one or more configuration messages402may indicate a type406of the QCL relation between the first transmission410and the second transmission430. As an example, the type406may correspond to one of multiple types specified by a wireless communication protocol, such as one of QCL-type A, QCL-type B, QCL-type C, or QCL-type D specified by a 5G NR wireless communication protocol.

In some examples, the UE115selects a spatial receive filter494based on the one or more configuration messages402. As examples, the one or more configuration messages402may indicate a same spatial receive filter494to be used by the UE115to receive the first transmission410and the second transmission430, or the UE115may determine the same spatial receive filter494based on the type406of the QCL relation between the first transmission410and the second transmission430. The UE115may receive the first transmission410and the second transmission430using the same spatial receive filter494.

In some other examples, the first transmission410and the second transmission430may have a non-QCL relation, are associated with differential spatial filters, or both. To illustrate, the one or more configuration messages402may request that the UE115provide the second measurement report440based on a differential format irrespective of whether the first transmission410has a QCL relation with the second transmission430and irrespective of whether the first transmission410and the second transmission430are associated with a same spatial transmit filter.

In some examples, the one or more configuration messages402indicate a compensation factor408associated with DMRS-based measurement reporting. To illustrate, in some cases, although the first transmission410has a QCL relation with the second transmission430, one or more characteristics of the first transmission410may differ with respect to the second transmission430. The compensation factor408may be selected (e.g., by the base station105) to account for the one or more characteristics. As illustrative examples, the one or more characteristics may include one or more of a change in beam pattern from the first transmission410to the second transmission430, a difference in precoding between the first transmission410and the second transmission430, a change in channel condition from the first transmission410to the second transmission430, or a change in scheduled bandwidth from the first transmission410to the second transmission430.

To compensate for the one or more characteristics, the UE115may apply the compensation factor408to one or more measurement results of the second measurement results460that are differential with respect to the first measurement report420. To illustrate, applying the compensation factor408to the one or more measurement results may include applying the compensation factor408to the second measurement result462(e.g., by adding, subtracting, multiplying, or dividing the second measurement result462and the compensation factor408) to determine an adjusted value. The UE115may subtract the adjusted value from the first measurement result422to determine the first value442. In such examples, the UE115may “pre-compensate” the second measurement results460prior to determining values of the second measurement report440that represent the second measurement results460. In some other examples, alternatively or in addition to indicating the compensation factor408to the UE115, the base station105may apply the compensation factor408(or another compensation factor) to measurement reports received from the UE115, such as the second measurement report440.

Alternatively or in addition to receiving an indication of the compensation factor408from the base station105, the UE115may determine a compensation factor using one or more other techniques. In some examples, the UE115applies a default compensation factor to the second measurement results460, such as a default compensation factor that is specified by a wireless communication protocol used by the base station105and the UE115. In some examples, the compensation factor408may correspond to an update to the default compensation factor that is to be applied to one or more subsequent DMRS-based measurement reports generated by the UE115.

In some implementations, the UE115may indicate one or more parameters or values by excluding a value from the second measurement report440. To illustrate, the UE115may determine that a change in a particular measurement result associated with the second measurement report440relative to a corresponding measurement result of the first measurement report420fails to satisfy a threshold difference, and the UE115may exclude a value446associated with the particular measurement result from the second measurement report440to indicate that the change fails to satisfy the threshold difference. In some examples, a DMRS resource indicator (DMRS-RI) corresponding to the value446is excluded from the second measurement report440, which may enable the base station105to detect exclusion of the value446from the second measurement report440. The second measurement report440may include DMRS-RIs associated with other values included in the second measurement report440, such as a first DMRS-RI associated with the first value442and a second DMRS-RI associated with the second value444. In some examples, the first DMRS-RI indicates a beam associated with the first value442, and the second DMRS-RI indicates a beam associated with the second value444.

The base station105may determine, based on the exclusion of the DMRS-RI corresponding to the value446, that the change fails to satisfy the threshold difference. In such examples, by excluding the value446from the second measurement report440, a data size of the second measurement report440may be reduced as compared to an example in which the second measurement report440includes the value446. It is noted that the change may be quantized to within a particular number of significant values (e.g., significant bits or significant digits) associated with the first measurement report420and the second measurement report440.

In some cases, the base station105may change a reporting format of DMRS-based measurement reports transmitted by the UE115(such as the second measurement report440). For example, a message of the one or more configuration messages402may change the format of the DMRS-based measurement reports transmitted by the UE. As an example, the message may indicate that the DMRS-based measurement reports are to be differential with respect to a third transmission from the base station105instead of with respect to the first transmission410. As an illustrative example, the first transmission410may include one of the SSB412, the CSI-RS414, or the DMRS416, and the third transmission may include another of the SSB412, the CSI-RS414, or the DMRS416. In some other examples, the message may indicate that the DMRS-based measurement reports are to include absolute values instead of differential values, such as the measurement results462,464instead of the values442,444.

One or more aspects of the disclosure may be used in connection with a single antenna port configuration, a multiple antenna port configuration, or a combination thereof. In some examples, the base station105performs the first transmission410using a single antenna port and performs the second transmission430using multiple antenna ports. The UE115may determine the second measurement result462based on an average of measurements determined over the multiple antenna ports. In such examples, the first value442is determined based on an average of measurements determined over multiple antenna ports. In some other examples, the base station105performs the first transmission410using a first group of antenna ports and performs the second transmission430using a second group of antenna ports. In such examples, the UE115may determine the first measurement result422based on a first average of measurements determined over the first group of antenna ports and may determine the second measurement result462based on a second average of measurements determined over the second group of antenna ports. In such examples, the first value442may be based on multiple averages of measurements, where each average is determined over multiple antenna ports.

FIG. 5is a diagram illustrating an example of inter-report and intra-report differential measurement reporting according to some aspects of the disclosure. In the example ofFIG. 5, the first transmission410is performed using two beams (B1and B2), the second transmission430is performed using four beams (D1, D2, D3, and D4), and a third transmission550is performed using four beams (D5, D6, D7, and D8). In some examples, the first transmission410includes the SSB412transmitted using the beams B1and B2, and the second transmission430includes a first DMRS (“DMRS1”) (e.g., the DMRS432) transmitted using the beams D1, D2, D3, and D4, and the third transmission550includes a second DMRS (“DMRS2”) transmitted using the beams D5, D6, D7, and D8. The UE115may transmit the second measurement report440based on DMRS1 and may transmit a third measurement report560based on DMRS2. Other examples are also within the scope of the disclosure.

InFIG. 5, the second measurement report440includes one or more values that are time differential with respect to the first measurement report420. For example, the first measurement report420may include a measurement M1, and the second measurement report440may include a value (M1′−M1) corresponding to a difference between the measurement M1 and a measurement M1′ that is based on DMRS1.

FIG. 5also illustrates that the second measurement report440may include one or more values that are differential with respect to the value (M1′−M1). For example, the second measurement report may further include a value (M2′) corresponding to a difference between the measurement M1′ and a measurement M2′ that is based on DMRS1.

FIG. 6is a diagram illustrating an example of inter-report differential measurement reporting according to some aspects of the disclosure. InFIG. 5, the second measurement report440includes values that are time differential with respect to the first measurement report420. For example, the first measurement report420may include a measurement M1, and the second measurement report440may include a value (M1′−M1) corresponding to a difference between the measurement M1 and a measurement M1′ that is based on DMRS1. As another example, the second measurement report440may include a value (M2′−M1) corresponding to a difference between the measurement M1 and a measurement M2′ that is based on DMRS1. To further illustrate, the first measurement report420may include a measurement M2. The second measurement report440may include a value (M3′−M2) corresponding to a difference between the measurement M2 and a measurement M3′ that is based on DMRS1. The second measurement report440may also include a value (M4′−M2) corresponding to a difference between the measurement M2 and a measurement M4′ that is based on DMRS1.

FIGS. 5 and 6also illustrate that transmissions may have multiple QCL relations. To illustrate, beam B1of the first transmission410may have a first QCL relation with beams D1and D2of DMRS1 and with beams D5and D6of DMRS2. Further, the beam B2of the first transmission410may have a second QCL relation with beams D3and D4of DMRS1 and with beams D7and D8of DMRS2. Thus, certain aspects described herein may be applicable to multiple QCL relations between transmissions.

To further illustrate, in some aspects of the disclosure, the second transmission430is performed via a first physical downlink shared channel (PDSCH) block, and the third transmission550is performed via a second PDSCH block. In some examples, the second transmission430and the third transmission550are performed using different sets of beams (e.g., to enable testing of the different sets of beams, in which case the base station105may select one of the sets of beams based on reception of the beams by the UE115). The UE115may transmit the second measurement report440using a particular set of beams, and the base station105may adjust, based on the particular set of beams, from a first set beams used to perform the second transmission430to a second set of beams used to perform the third transmission550. In some examples, DMRS1 and DMRS2 are transmitted using a same transmit beam. The UE115may adjust, based on the same transmit beam, a receive beam of the UE used to receive transmissions from the base station105.

One or more aspects described herein may improve performance of a wireless communication system. For example, by using a differential format to report measurements, an amount of data transmitted via the wireless communication system400may be reduced, which may be particular advantageous in some low-overhead wireless communication protocols, such as a RedCap wireless communication protocol. To illustrate, in some wireless communication protocols, the measurement results450,460may include a relatively large number of bits or digits and may change relatively infrequently (such as in the case of stationary sensors in a building, as an illustrative example). Further, in some cases, a DMRS (such as the DMRS432) may serve multiple purposes in the wireless communication system400, which may reduce a number of reference signals or a number of resources associated with reference signals in the wireless communication system. For example, in addition to using the DMRS432to estimate channel characteristics and demodulate signals received from the base station105, the UE115may report measurements based on the DMRS432(using the second measurement report440). As a result, one or more of a periodicity of the CSI-RS414or SSB412or a number of resources used to transmit the CSI-RS414or the SSB412may be reduced, increasing bandwidth or resources available for other communications, for other devices, or both.

FIG. 7is a flow chart of a method700of wireless communication according to some aspects of the disclosure. In some examples, the method700is performed by a UE, such as the UE115.

The method700includes receiving, by a UE, a first transmission, at702. For example, the UE115may receive the first transmission410from the base station105.

The method700further includes transmitting, by the UE, a first measurement report that is based on the first transmission and includes at least a first measurement result, at704. For example, the UE115may transmit the first measurement report420based on the first transmission410and including at least the first measurement result422.

The method700further includes receiving, by the UE, a second transmission that includes a DMRS, at706. For example, the UE115may receive the second transmission430from the base station105, and the second transmission430may include the DMRS432.

The method700further includes transmitting, by the UE, a second measurement report that is based on the DMRS, at708. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS. For example, the UE115may transmit the second measurement report440based on the DMRS432, and the second measurement report440may include the first value442that is based on the difference424between the first measurement result422and the second measurement result462. The second measurement result462is based on the DMRS432.

FIG. 8is a flow chart of a method800of wireless communication according to some aspects of the disclosure. In some examples, the method800is performed by a base station, such as the base station105.

The method800includes transmitting, by a base station, a first transmission, at802. For example, the base station105may transmit the first transmission410to the UE115.

The method800further includes receiving, by the base station, a first measurement report that is based on the first transmission and includes at least a first measurement result, at804. For example, the base station105may receive the first measurement report420from the UE115, and the first measurement report420may include the first measurement result422.

The method800further includes transmitting, by the base station, a second transmission that includes a DMRS, at806. For example, the base station105may transmit the second transmission430to the UE115including the DMRS432.

The method800further includes receiving, by the base station, a second measurement report that is based on the DMRS, at808. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS. For example, the base station105may receive the second measurement report440from the UE115based on the DMRS432, and the second measurement report440may include the first value442that is based on the difference424between the first measurement result422and the second measurement result462. The second measurement result462is based on the DMRS432.

FIG. 9is a block diagram illustrating an example of a UE115according to some aspects of the disclosure. The UE115may include structure, hardware, or components illustrated inFIG. 2. For example, the UE115may include the controller/processor280, which may execute instructions stored in the memory282. Using the controller/processor280, the UE115may transmit and receive signals via wireless radios901a-rand antennas252a-r. The wireless radios901a-rmay include one or more components or devices described herein, such as the modulator/demodulators254a-r, the MIMO detector256, the receive processor258, the transmit processor264, the TX MIMO processor266, the transmitter490, the receiver492, one or more other components or devices, or a combination thereof.

The memory282may store instructions executable by the controller/processor280to initiate, perform, or control one or more operations described herein. For example, the memory282may store measurement instructions902executable by the controller/processor280to generate the first measurement results450based on the first transmission410and to generate the second measurement results460based on the second transmission430. As another example, the memory282may store differential reporting instructions904executable by the controller/processor280to generate the second measurement report440.

FIG. 10is a block diagram illustrating an example of a base station105according to some aspects of the disclosure. The base station105may include structure, hardware, and components illustrated inFIG. 2. For example, the base station105may include the controller/processor240, which may execute instructions stored in memory242. Under control of the controller/processor240, the base station105may transmit and receive signals via wireless radios1001a-tand antennas234a-t. The wireless radios1001a-tmay include one or more components or devices described herein, such as the modulator/demodulators232a-t, the MIMO detector236, the receive processor238, the transmit processor220, the TX MIMO processor230, the transmitter480, the receiver484, one or more other components or devices, or a combination thereof.

The memory242may store instructions executable by the controller/processor240to initiate, perform, or control one or more operations described herein. For example, the memory242may store transmit instructions1002executable by the controller/processor240to initiate, perform, or control one or more transmissions, such as to transmission of the one or more configuration messages402, the first transmission410, and the second transmission430, as illustrative examples. As another example, the memory242may store inverse differential reporting instructions1004executable by the controller/processor240to determine a measurement result based on a differential value reported by the UE115and based on another value or measurement result. For example, in some implementations, after receiving the first measurement report420and the second measurement report440, the controller/processor240may execute the inverse differential reporting instructions1004to determine the second measurement result462based on a sum of the first measurement result422and the first value442.

According to some further aspects, in a first aspect, a method of wireless communication includes receiving, by a UE, a first transmission and transmitting, by the UE, a first measurement report that is based on the first transmission and includes at least a first measurement result. The method further includes receiving, by the UE, a second transmission that includes a DMRS and further includes transmitting, by the UE, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a second aspect alternatively or in addition to the first aspect, the second measurement report further includes at least a second value that is based on a difference between the second measurement result and a third measurement result that is based on the DMRS.

In a third aspect alternatively or in addition to one or more of the first through second aspects, the second measurement report further includes at least a second value that is based on a difference between the first measurement result and a third measurement result that is based on the DMRS.

In a fourth aspect alternatively or in addition to one or more of the first through third aspects, the method includes receiving, by the UE, a message indicating that the first transmission and the second transmission are associated with a same spatial transmit filter.

In a fifth aspect alternatively or in addition to one or more of the first through fourth aspects, the second transmission has a QCL relation with the first transmission, and the message further indicates a type of the QCL relation.

In a sixth aspect alternatively or in addition to one or more of the first through fifth aspects, the method includes selecting a same spatial receiver filter based on the message, and the UE receives the first transmission and the second transmission using the same spatial filter.

In a seventh aspect alternatively or in addition to one or more of the first through sixth aspects, the method includes applying a compensation factor to one or more measurement results that are differential with respect to the first measurement report, where applying the compensation factor to the one or more measurement results includes applying the compensation factor to the second measurement result to determine an adjusted value and subtracting the adjusted value from the first measurement result to determine the first value.

In an eighth aspect alternatively or in addition to one or more of the first through seventh aspects, the compensation factor is selected to account for one or more of a change in beam pattern from the first transmission to the second transmission, a difference in precoding between the first transmission and the second transmission, a change in channel condition from the first transmission to the second transmission, or a change in scheduled bandwidth from the first transmission to the second transmission.

In a ninth aspect alternatively or in addition to one or more of the first through eighth aspects, the method includes receiving, by the UE, a message indicating the compensation factor.

In a tenth aspect alternatively or in addition to one or more of the first through ninth aspects, the message requests that the UE provide the second measurement report based on a differential format irrespective of whether the first transmission has a QCL relation with the second transmission and irrespective of whether the first transmission and the second transmission are associated with a same spatial transmit filter.

In an eleventh aspect alternatively or in addition to one or more of the first through tenth aspects, the method includes determining, by the UE, that a change in a particular measurement result associated with the second measurement report relative to a corresponding measurement result of the first measurement report fails to satisfy a threshold difference, and the second measurement report excludes a value associated with the particular measurement result indicating that the change fails to satisfy the threshold difference.

In a twelfth aspect alternatively or in addition to one or more of the first through eleventh aspects, the change is quantized to within a particular number of significant values associated with the first measurement report and the second measurement report.

In a thirteenth aspect alternatively or in addition to one or more of the first through twelfth aspects, the first transmission is associated with a single antenna port, the second transmission is associated with multiple antenna ports, and the second measurement result is determined based on an average of measurements determined over the multiple antenna ports.

In a fourteenth aspect alternatively or in addition to one or more of the first through thirteenth aspects, the first transmission is associated with a first group of antenna ports, the second transmission is associated with a second group of antenna ports, the first measurement result is determined based on a first average of measurements determined over the first group of antenna ports, and the second measurement result is determined based on a second average of measurements determined over the second group of antenna ports.

In a fifteenth aspect alternatively or in addition to one or more of the first through fourteenth aspects, receiving, by the UE, a message changing a format of DMRS-based measurement reports transmitted by the UE.

In a sixteenth aspect alternatively or in addition to one or more of the first through fifteenth aspects, the message indicates that the DMRS-based measurement reports are to be differential with respect to a third transmission instead of with respect to the first transmission.

In a seventeenth aspect alternatively or in addition to one or more of the first through sixteenth aspects, the message indicates that the DMRS-based measurement reports are to include absolute values instead of differential values.

In an eighteenth aspect alternatively or in addition to one or more of the first through seventeenth aspects, an apparatus for wireless communication includes a receiver configured to receive a first transmission and to receive a second transmission that includes a DMRS. The apparatus further includes a transmitter configured to transmit a first measurement report that is based on the first transmission and that includes at least a first measurement result and to transmit a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a nineteenth aspect alternatively or in addition to one or more of the first through eighteenth aspects, the second measurement report further includes at least a second value, and further comprising a processor configured to determine the second value based on a difference between the second measurement result and a third measurement result that is based on the DMRS.

In a twentieth aspect alternatively or in addition to one or more of the first through nineteenth aspects, the second measurement report further includes at least a second value, and further comprising a processor configured to determine the second value based on a difference between the first measurement result and a third measurement result that is based on the DMRS.

In a twenty-first aspect alternatively or in addition to one or more of the first through twentieth aspects, a method of wireless communication includes transmitting, by a base station, a first transmission and receiving, by the base station, a first measurement report that is based on the first transmission and includes at least a first measurement result. The method further includes transmitting, by the base station, a second transmission that includes a DMRS and receiving, by the base station, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a twenty-second aspect alternatively or in addition to one or more of the first through twenty-first aspects, the second measurement report further includes at least a second value that is based on a difference between the second measurement result and a third measurement result that is based on the DMRS.

In a twenty-third aspect alternatively or in addition to one or more of the first through twenty-second aspects, the second measurement report further includes at least a second value that is based on a difference between the first measurement result and a third measurement result that is based on the DMRS.

In a twenty-fourth aspect alternatively or in addition to one or more of the first through twenty-third aspects, transmitting a message indicating that the first transmission and the second transmission are associated with a same spatial transmit filter.

In a twenty-fifth aspect alternatively or in addition to one or more of the first through twenty-fourth aspects, the second transmission has a QCL relation with the first transmission, and the message further indicates a type of the QCL relation.

In a twenty-sixth aspect alternatively or in addition to one or more of the first through twenty-fifth aspects, the method includes transmitting a message indicating a compensation factor that is selected to account for one or more of a change in beam pattern from the first transmission to the second transmission, a difference in precoding between the first transmission and the second transmission, a change in channel condition from the first transmission to the second transmission, or a change in scheduled bandwidth from the first transmission to the second transmission.

In a twenty-seventh aspect alternatively or in addition to one or more of the first through twenty-sixth aspects, the method includes transmitting a message changing a format of DMRS-based measurement reports.

In a twenty-eighth aspect alternatively or in addition to one or more of the first through twenty-seventh aspects, an apparatus for wireless communication includes a transmitter configured to transmit a first transmission and to transmit a second transmission that includes a DMRS. The apparatus further includes a receiver configured to receive a first measurement report that is based on the first transmission and includes at least a first measurement result and to receive a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a twenty-ninth aspect alternatively or in addition to one or more of the first through twenty-eighth aspects, the second measurement report further includes at least a second value that is based on a difference between the second measurement result and a third measurement result that is based on the DMRS.

In a thirtieth aspect alternatively or in addition to one or more of the first through twenty-ninth aspects, the second measurement report further includes at least a second value that is based on a difference between the first measurement result and a third measurement result that is based on the DMRS.

In a thirty-first aspect alternatively or in addition to one or more of the first through thirtieth aspects, a non-transitory computer-readable medium stores instructions executable by a processor to initiate, perform, or control operations. The operations include receiving, by a UE, a first transmission and transmitting, by the UE, a first measurement report that is based on the first transmission and includes at least a first measurement result. The operations further include receiving, by the UE, a second transmission that includes a DMRS and further includes transmitting, by the UE, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a thirty-second aspect alternatively or in addition to one or more of the first through thirty-first aspects, an apparatus for wireless communication includes means for receiving a first transmission and for receiving a second transmission that includes a DMRS. The apparatus further includes means for transmitting a first measurement report that is based on the first transmission and that includes at least a first measurement result and for transmitting a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a thirty-third aspect alternatively or in addition to one or more of the first through thirty-second aspects, a non-transitory computer-readable medium stores instructions executable by a processor to initiate, perform, or control operations. The operations include transmitting, by a base station, a first transmission and receiving, by the base station, a first measurement report that is based on the first transmission and includes at least a first measurement result. The operations further include transmitting, by the base station, a second transmission that includes a DMRS and receiving, by the base station, a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

In a thirty-fourth aspect alternatively or in addition to one or more of the first through thirty-third aspects, an apparatus for wireless communication includes a transmitter configured to transmit a first transmission and to transmit a second transmission that includes a DMRS. The apparatus further includes a receiver configured to receive a first measurement report that is based on the first transmission and includes at least a first measurement result and to receive a second measurement report that is based on the DMRS. The second measurement report includes at least a first value that is based on a difference between the first measurement result and a second measurement result that is based on the DMRS.

One or more components, functional blocks, and devices described herein (e.g., one or more components, functional blocks, and devices ofFIG. 2) may include one or more processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, etc., or any combination thereof. Those of skill would further appreciate that the various illustrative logical blocks, devices, circuits, and operations described herein may be implemented using electronic hardware, computer software, or combinations of both. To illustrate, various components, blocks, devices, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design parameters of the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. Skilled artisans will also readily recognize that the order or combination of components, methods, or interactions that are described herein are merely examples and that the components, methods, or interactions of the various aspects of the present disclosure may be combined or performed in ways other than those illustrated and described herein.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, a connection may be properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), hard disk, solid state disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.