Patent Description:
The present application relates to wireless devices, and more particularly to apparatus, systems, and methods for providing downlink control for multi-TRP transmissions.

Wireless communication systems are rapidly growing in usage. In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS), and are capable of operating sophisticated applications that utilize these functionalities. Additionally, there exist numerous different wireless communication technologies and standards. Some examples of wireless communication standards include GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE Advanced (LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), IEEE <NUM> (WLAN or Wi-Fi), BLUETOOTH™, etc..

The ever increasing number of features and functionality introduced in wireless communication devices also creates a continuous need for improvement in both wireless communications and in wireless communication devices. To increase coverage and better serve the increasing demand and range of envisioned uses of wireless communication, in addition to the communication standards mentioned above, there are further wireless communication technologies under development, including fifth generation (<NUM>) new radio (NR) communication. Accordingly, improvements in the field in support of such development and design are desired. <CIT> discloses methods, apparatuses and systems for transmission of a CSI report. A WTRU may receive an aperiodic CSI reporting request on a PDCCH. The WTRU may determine a time gap between a last symbol of the PDCCH of which the aperiodic CSI reporting request is received and a first uplink symbol of a designated uplink channel for transmission of a corresponding aperiodic CSI report. The determination of the time gap may include consideration of a timing advance value. A determination may be made as to whether a time threshold is shorter than the determined time gap. If the determined time gap is not shorter than the time threshold, the WTRU may transmit the CSI report. If the determined time gap is shorter than the threshold, the WTRU may not transmit the CSI report. <CIT> discloses a method for performing coordinated transmission in a wireless communication system and an apparatus therefor.

Embodiments relate to apparatuses, systems, and methods to provide downlink control for multi-TRP transmission.

According to the techniques described herein, a cellular base station may provide a downlink control information transmission to a wireless device scheduling downlink transmissions to the wireless device from multiple transmission reception points. The downlink control information may include information that can be used by the wireless device to determine any or all of physical resource block bundling sizes, frequency domain resource allocations, modulation and coding schemes, redundancy versions, phase tracking reference signal configurations, and any of various other possible types of configuration information for the downlink transmissions.

Using the downlink control information, the wireless device may be able to determine the resource allocations and various other configuration details for the downlink transmissions, and thus may be able to receive and decode the downlink transmissions from the plurality of transmission reception points in accordance with the downlink control information.

Thus, the techniques described herein may be used to support a single downlink control information format for scheduling multi-TRP downlink transmissions, at least according to some embodiments.

The techniques described herein may be implemented in and/or used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the subject matter as defined by the appended claims.

The base station (BS) 102A may be a base transceiver station (BTS) or cell site (a "cellular base station"), and may include hardware that enables wireless communication with the UEs 106A through 106N.

The communication area (or coverage area) of the base station may be referred to as a "cell. " The base station 102A and the UEs <NUM> may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), <NUM> new radio (<NUM> NR), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc. Note that if the base station 102A is implemented in the context of LTE, it may alternately be referred to as an 'eNodeB' or 'eNB'. Note that if the base station 102A is implemented in the context of <NUM> NR, it may alternately be referred to as a 'gNodeB' or 'gNB'.

In some embodiments, base station 102A may be a next generation base station, e.g., a <NUM> New Radio (<NUM> NR) base station, or "gNB". In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network and/or to a NR core (NRC) network. In addition, a gNB cell may include one or more transition and reception points (TRPs). For example, it may be possible that that the base station 102A and one or more other base stations <NUM> support joint transmission, such that UE <NUM> may be able to receive transmissions from multiple base stations (and/or multiple TRPs provided by the same base station).

Note that a UE <NUM> may be capable of communicating using multiple wireless communication standards. For example, the UE <NUM> may be configured to communicate using a wireless networking (e.g., Wi-Fi) and/or peer-to-peer wireless communication protocol (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, <NUM> NR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc.). The UE <NUM> may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS, e.g., GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M/H), and/or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

<FIG> illustrates user equipment <NUM> (e.g., one of the devices 106A through 106N) in communication with a base station <NUM>, according to some embodiments. The UE <NUM> may be a device with cellular communication capability such as a mobile phone, a hand-held device, a computer, a laptop, a tablet, a smart watch or other wearable device, or virtually any type of wireless device.

The UE <NUM> may include a processor (processing element) that is configured to execute program instructions stored in memory. Alternatively, or in addition, the UE <NUM> may include a programmable hardware element such as an FPGA (field-programmable gate array), an integrated circuit, and/or any of various other possible hardware components that are configured to perform (e.g., individually or in combination) any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

The UE <NUM> may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, the UE <NUM> may be configured to communicate using, for example, NR or LTE using at least some shared radio components. As additional possibilities, the UE <NUM> could be configured to communicate using CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD) or LTE using a single shared radio and/or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE <NUM> may share one or more parts of a receive and/or transmit chain between multiple wireless communication technologies, such as those discussed above.

For example, the UE <NUM> might include a shared radio for communicating using either of LTE or <NUM> NR (or either of LTE or 1xRTT, or either of LTE or GSM, among various possibilities), and separate radios for communicating using each of Wi-Fi and Bluetooth.

<FIG> illustrates an example simplified block diagram of a communication device <NUM>, according to some embodiments. It is noted that the block diagram of the communication device of <FIG> is only one example of a possible communication device. According to embodiments, communication device <NUM> may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet, and/or a combination of devices, among other devices. As shown, the communication device <NUM> may include a set of components <NUM> configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOC), which may include portions for various purposes. Alternatively, this set of components <NUM> may be implemented as separate components or groups of components for the various purposes. The set of components <NUM> may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the communication device <NUM>.

For example, the communication device <NUM> may include various types of memory (e.g., including NAND flash <NUM>), an input/output interface such as connector I/F <NUM> (e.g., for connecting to a computer system; dock; charging station; input devices, such as a microphone, camera, keyboard; output devices, such as speakers; etc.), the display <NUM>, which may be integrated with or external to the communication device <NUM>, and wireless communication circuitry <NUM> (e.g., for LTE, LTE-A, NR, UMTS, GSM, CDMA2000, Bluetooth, Wi-Fi, NFC, GPS, etc.).

The wireless communication circuitry <NUM> may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antenna(s) <NUM> as shown. The wireless communication circuitry <NUM> may include cellular communication circuitry and/or short to medium range wireless communication circuitry, and may include multiple receive chains and/or multiple transmit chains for receiving and/or transmitting multiple spatial streams, such as in a multiple-input multiple output (MIMO) configuration.

In some embodiments, as further described below, cellular communication circuitry <NUM> may include one or more receive chains (including and/or coupled to (e.g., communicatively; directly or indirectly) dedicated processors and/or radios) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for <NUM> NR). For example, a first radio may be dedicated to a first RAT, e.g., LTE, and may be in communication with a dedicated receive chain and a transmit chain shared with a second radio. The second radio may be dedicated to a second RAT, e.g., <NUM> NR, and may be in communication with a dedicated receive chain and the shared transmit chain.

As shown, the SOC <NUM> may include processor(s) <NUM>, which may execute program instructions for the communication device <NUM> and display circuitry <NUM>, which may perform graphics processing and provide display signals to the display <NUM>. The processor(s) <NUM> may also be coupled to memory management unit (MMU) <NUM>, which may be configured to receive addresses from the processor(s) <NUM> and translate those addresses to locations in memory (e.g., memory <NUM>, read only memory (ROM) <NUM>, NAND flash memory <NUM>) and/or to other circuits or devices, such as the display circuitry <NUM>, wireless communication circuitry <NUM>, connector I/F <NUM>, and/or display <NUM>. The MMU <NUM> may be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU <NUM> may be included as a portion of the processor(s) <NUM>.

As noted above, the communication device <NUM> may be configured to communicate using wireless and/or wired communication circuitry. As described herein, the communication device <NUM> may include hardware and software components for implementing any of the various features and techniques described herein. The processor <NUM> of the communication device <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM> of the communication device <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be configured to implement part or all of the features described herein.

Further, as described herein, wireless communication circuitry <NUM> may include one or more processing elements. In other words, one or more processing elements may be included in wireless communication circuitry <NUM>. Thus, wireless communication circuitry <NUM> may include one or more integrated circuits (ICs) that are configured to perform the functions of wireless communication circuitry <NUM>. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of wireless communication circuitry <NUM>.

As another possibility, the base station <NUM> may include a multi-mode radio which is capable of performing communications according to any of multiple wireless communication technologies (e.g., <NUM> NR and LTE, <NUM> NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

In addition, as described herein, processor(s) <NUM> may include one or more processing elements.

Further, as described herein, radio <NUM> may include one or more processing elements.

<FIG> illustrates an example simplified block diagram of cellular communication circuitry, according to some embodiments. It is noted that the block diagram of the cellular communication circuitry of <FIG> is only one example of a possible cellular communication circuit; other circuits, such as circuits including or coupled to sufficient antennas for different RATs to perform uplink activities using separate antennas, or circuits including or coupled to fewer antennas, e.g., that may be shared among multiple RATs, are also possible. According to some embodiments, cellular communication circuitry <NUM> may be included in a communication device, such as communication device <NUM> described above. As noted above, communication device <NUM> may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet and/or a combination of devices, among other devices.

The cellular communication circuitry <NUM> may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 335a-b and <NUM> as shown. In some embodiments, cellular communication circuitry <NUM> may include dedicated receive chains (including and/or coupled to (e.g., communicatively; directly or indirectly) dedicated processors and/or radios) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for <NUM> NR). For example, as shown in <FIG>, cellular communication circuitry <NUM> may include a first modem <NUM> and a second modem <NUM>. The first modem <NUM> may be configured for communications according to a first RAT, e.g., such as LTE or LTE-A, and the second modem <NUM> may be configured for communications according to a second RAT, e.g., such as <NUM> NR.

As shown, the first modem <NUM> may include one or more processors <NUM> and a memory <NUM> in communication with processors <NUM>.

Similarly, the second modem <NUM> may include one or more processors <NUM> and a memory <NUM> in communication with processors <NUM>.

Thus, when cellular communication circuitry <NUM> receives instructions to transmit according to the first RAT (e.g., as supported via the first modem <NUM>), switch <NUM> may be switched to a first state that allows the first modem <NUM> to transmit signals according to the first RAT (e.g., via a transmit chain that includes transmit circuitry <NUM> and UL front end <NUM>). Similarly, when cellular communication circuitry <NUM> receives instructions to transmit according to the second RAT (e.g., as supported via the second modem <NUM>), switch <NUM> may be switched to a second state that allows the second modem <NUM> to transmit signals according to the second RAT (e.g., via a transmit chain that includes transmit circuitry <NUM> and UL front end <NUM>).

As described herein, the first modem <NUM> and/or the second modem <NUM> may include hardware and software components for implementing any of the various features and techniques described herein. The processors <NUM>, <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processors <NUM>, <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processors <NUM>, <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> may be configured to implement part or all of the features described herein.

In addition, as described herein, processors <NUM>, <NUM> may include one or more processing elements. Thus, processors <NUM>, <NUM> may include one or more integrated circuits (ICs) that are configured to perform the functions of processors <NUM>, <NUM>. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of processors <NUM>, <NUM>.

In some embodiments, the cellular communication circuitry <NUM> may include only one transmit/receive chain. For example, the cellular communication circuitry <NUM> may not include the modem <NUM>, the RF front end <NUM>, the DL front end <NUM>, and/or the antenna 335b. As another example, the cellular communication circuitry <NUM> may not include the modem <NUM>, the RF front end <NUM>, the DL front end <NUM>, and/or the antenna 335a. In some embodiments, the cellular communication circuitry <NUM> may also not include the switch <NUM>, and the RF front end <NUM> or the RF front end <NUM> may be in communication, e.g., directly, with the UL front end <NUM>.

New cellular communication techniques are continually under development, to increase coverage, to better serve the range of demands and use cases, and for a variety of other reasons. One technique that is currently under development may include scheduling transmissions in which multiple TRPs can transmit downlink data to a wireless device. As part of such development, it would be useful to provide a downlink control framework that can support such a technique.

Accordingly, <FIG> is a signal flow diagram illustrating an example of such a method, at least according to some embodiments. Aspects of the method of <FIG> may be implemented by a wireless device such as a UE <NUM> illustrated in various of the Figures herein, a base station such as a BS <NUM> illustrated in various of the Figures herein, and/or more generally in conjunction with any of the computer circuitry, systems, devices, elements, or components shown in the above Figures, among others, as desired. For example, a processor (and/or other hardware) of such a device may be configured to cause the device to perform any combination of the illustrated method elements and/or other method elements.

In various embodiments, some of the elements of the methods shown may be performed concurrently, in a different order than shown, may be substituted for by other method elements, or may be omitted. Additional elements may also be performed as desired. As shown, the method of <FIG> may operate as follows.

At <NUM>, a wireless device receives downlink control information (DCI) for a multi-TRP transmission. The DCI may be provided in any of a variety of possible formats. At least according to some embodiments, the wireless device may receive an indication of which of multiple possible formats is being used to provide the DCI. For example, such information may be broadcast by a base station to which the wireless device is attached in a system information broadcast, among various other possibilities.

As one possible format, the DCI may be provided as a single DCI transmission from a cellular base station that includes scheduling information for multiple downlink data streams. The cellular base station may provide all of the multiple TRPs from which the downlink transmissions are scheduled, or may provide only a subset of the multiple TRPs from which the downlink transmissions are scheduled, while one or more of the TRPs from which the downlink transmissions are scheduled could be provided by one or more other cellular base stations, according to some embodiments.

In case of a single DCI transmission being used to schedule the multi-TRP transmission, the DCI may include entirely separate / independent scheduling information for each downlink data stream, or may include some scheduling information that is common to the downlink data streams and some scheduling information that is separate / independent for each of the downlink data streams, e.g., to more efficiently communicate the scheduling information.

According to some embodiments, the downlink transmissions may include physical downlink shared channel (PDSCH) blocks that are provided by the multiple TRPs using frequency division multiplexing techniques, e.g., such that the different PDSCH blocks have different frequency resource allocations, which may each include a certain number of resource blocks (RBs), which may in turn be bundled according to any of multiple possible physical RB (PRB) bundling sizes.

In such a scenario, it may be the case that the DCI includes information that can be used by the wireless device to determine (PRB) bundling sizes for the downlink transmissions. For example, it may be the case that different PRB bundling sizes could be configured for the downlink transmissions from the different TRPs. In such a case, PRB bundling related parameters could be indicated for each downlink transmission. The wireless device may thus be able to determine PRB bundling sizes separately for the downlink transmissions from the plurality of TRPs scheduled by the DCI transmission, at least as one possibility. As another possibility, the PRB bundling size could be common across all of the downlink transmissions scheduled by the DCI. In such a case, PRB bundling related parameters could be indicated for all of the downlink transmissions commonly, or PRB bundling related parameters could still be indicated for each downlink transmission, and the wireless device could determine the common PRB bundling size using a specified or otherwise predetermined technique based on the indicated PRB bundling size for each downlink transmission, such as by selecting the maximum PRB bundling size among the indicated PRB bundling sizes for the downlink transmissions, or by selecting the minimum PRB bundling size among the indicated PRB bundling sizes for the downlink transmissions.

At least in some instances, the DCI may include information that can be used by the wireless device to determine the frequency domain resource allocations for the downlink transmissions. For example, as one possibility, the DCI may include an indication of the frequency domain resource allocation for each of the downlink transmissions, such that the wireless device may be able to determine the frequency domain resource allocation for each of the downlink transmissions based at least in part on the indication of the frequency domain resource allocation for each of the downlink transmissions. As another possibility, the DCI may include a frequency domain resource allocation indicator that configures frequency resources for all of the downlink transmissions. For example, the frequency domain resource allocation indicator could include a combinatorial index that is calculated based on a start resource block index value and an end resource block index value for each of the downlink transmissions. The calculation could be performed in a predetermined manner such that the resulting combinatorial index could be used by the wireless device to determine the start resource block index value and an end resource block index value for each of the downlink transmissions (and thus the frequency domain resource allocation) for each of the downlink transmissions in turn. Such an approach may result in a lower signaling overhead to indicate the frequency domain resource allocations than would result from including an indication of the frequency domain resource allocation for each of the downlink transmissions, at least according to some embodiments.

According to some embodiments, the DCI may include information that can be used by the wireless device to determine the modulation and coding scheme (MCS) and a redundancy version (RV) for each of the downlink transmissions. For example, as one possibility, the DCI may include an indication of the MCS and the RV for each of the downlink transmissions, such that the wireless device may be able to determine the MCS and the RV for each of the downlink transmissions based at least in part on the indication of the MCS and the RV for each of the downlink transmissions. According to the invention, the DCI may include an indication of a MCS and a RV for a first downlink transmission of the downlink transmissions, and a predetermined or configured approach to determining the MCS and RV for each of the other downlink transmissions may be specified. For example, in some embodiments, a common MCS may be used for all of the downlink transmissions, and one MCS indication may be sufficient to indicate the MCS for each of the downlink transmissions. Similarly, in some embodiments, each downlink transmission may have the same RV, such that one RV indication may be sufficient to indicate the RV for each of the downlink transmissions. As another possibility, it may be possible to determine the RV for each downlink transmission for which the RV is not directly indicated in a predetermined or dynamically configured manner based at least in part on the indicated RV. For example, the RV for a second downlink transmission could be calculated based on the RV for the first transmission according to the formula RV2 = (RV1+<NUM>) mod <NUM>, as one possibility. The specified technique for determining the RV for each downlink transmission for which the RV is not directly indicated could alternatively or additionally be based at least in part on the resource allocation for the that downlink transmission (e.g., the first PRB index of that downlink transmission), and/or based on any of various other considerations, as desired.

According to some embodiments, the DCI may include information that can be used by the wireless device to determine the phase tracking reference signal (PT-RS) configuration for the downlink transmissions. For example, as one possibility, a common PT-RS pattern may be transmitted in conjunction with all of the downlink transmissions. In such a scenario, the PT-RS frequency domain pattern for the downlink transmissions could be determined based at least in part on the number of resource blocks associated with each of the downlink transmissions. For example, the PT-RS frequency domain presence, density, and pattern could be determined using a table mapping scheduled bandwidth to frequency density of the PT-RS, and the scheduled bandwidth used for the mapping could include the number of resource blocks associated with a specified one of the downlink transmissions (e.g., the number of resource blocks associated with a first downlink transmission, or the number of resource blocks associated with a second downlink transmission, etc.), or could include the minimum number of resource blocks scheduled among the downlink transmissions, or could include the maximum number of resource blocks scheduled among the downlink transmissions, or could include the sum total number of resource blocks scheduled in the downlink transmissions, among various other possibilities.

In a scenario in which a common PT-RS pattern is transmitted in conjunction with all of the downlink transmissions, if the MCS is common for all of the downlink transmissions, it may be the case that the wireless device can determine the PT-RS time domain pattern based on the indicated common MCS. Alternatively, if the different downlink transmissions from the different TRPs have different MCS configurations, the PT-RS time domain pattern could be determined based at least in part on the configured MCS for each of the downlink transmissions. For example, the PT-RS time domain pattern could be selected based on the minimum MCS among the downlink transmissions, or based on the maximum MCS among the downlink transmissions, or based on an equivalent overall MCS determined based on the MCS for each of the downlink transmissions, among various possibilities.

As another possible scenario, separate PT-RS patterns could be used for each downlink transmission. In such a scenario, the wireless device may be able to determine the PT-RS pattern separately for each of the downlink transmissions, e.g., based at least in part on the number of scheduled RBs and the MCS associated with each of the downlink transmissions.

In some embodiments, the downlink transmissions may be providing using spatial division multiplexing techniques. In such a scenario, it may be the case that the DCI indicates a demodulation reference signal (DMRS) port allocation for each of the downlink transmissions, and that the wireless device is able to determine a PT-RS port associated with each of the downlink transmissions based at least in part on the DMRS port allocation. For example, the PT-RS port for a given transmission may be associated with the lowest DMRS port index, as one possibility. As another possibility, the PT-RS port for a given transmission could be associated with the highest DMRS port index for that transmission.

In <NUM>, the wireless device receives the downlink transmissions from the multiple TRPs in accordance with the DCI. This may include utilizing the various parameters and configuration information provided in and/or determined based on the DCI to receive and decode each of the multiple downlink transmissions.

Thus, the method of <FIG> may be used by multiple TRPs and a wireless device to schedule and perform a multi-TRP downlink communication to the wireless device, at least according to some embodiments.

Figures <NUM>-<NUM> illustrate further aspects that might be used in conjunction with the method of <FIG> if desired. It should be noted, however, that the exemplary details illustrated in and described with respect to Figures <NUM>-<NUM> are not intended to be limiting to the disclosure as a whole: numerous variations and alternatives to the details provided herein below are possible and should be considered within the scope of the disclosure.

<FIG> illustrates an example scenario in which two transmission reception points (TRPs) schedule two data streams to a wireless device, according to some embodiments. Such multi-TRP operation may include non coherent joint transmission (NCJT) communication, as one possibility. Other forms of multi-TRP operation are also possible.

There may be a variety of options for providing a signaling framework for scheduling such multi-TRP operation. As one possibility, a single downlink control information (DCI) communication may be used to schedule different physical downlink control channel (PDSCH) blocks for a UE from different TRPs. The different PDSCH blocks may be provided using a frequency division multiplexing scheme, as one possibility. <FIG> illustrates possible time and frequency resource usage in one example of such a scheme, in which the two different PDSCH blocks share the same redundancy version (RV). <FIG> illustrates possible time and frequency resource usage in another example of such a scheme, in which the two different PDSCH blocks are allocated different RVs. As a still further possibility, a spatial domain multiplexing (SDM) based approach to providing different PDSCH blocks from different TRPs to a UE may be used. In such a scenario, it may be the case that different demodulation reference signal (DMRS) ports can correspond to different TRPs.

One aspect of configuring a downlink communication may include indicating (e.g., by the network) and determining (e.g., by the UE) the physical resource block (PRB) bundling size for the downlink communication. <FIG> is a flowchart diagram illustrating one possible scheme that may be used by a UE to determine the PRB bundling size for a PDSCH communication, according to some embodiments. As shown, in <NUM>, the UE may determine if the RRC parameter prb-BundlingType is configured. In <NUM>, if it is not, the UE may determine that a default PRB bundling size (e.g., <NUM> RBs, in the illustrated scenario) is configured. In <NUM>, if the RRC parameter prb-BundlingType is configured, it may be determined if the prb-BundlingType parameter is set to dynamicBundling. If it is not, in <NUM>, the UE may determine that the PRB group size is configured by the RRC parameter bundleSizeSet2 (e.g., which may be selected from an enumerated set of PRB bundle size options). In <NUM>, if the prb-BundlingType parameter is set to dynamicBundling, the UE may further determine if one value is configured in the RRC parameter bundleSizeSet1. If so, in <NUM>, the UE may determine the PRG size based on the higher layer parameter bundleSizeSet1 (e.g., which may be selected from an enumerated set of PRB bundle size options). If not, in <NUM>, the UE may determine if the scheduled set of PRBs is contiguous and if the number of scheduled PRBs is above half of the bandwidth of the active bandwidth part. If not, in <NUM>, the UE may determine that the PRG size is wideband. If so, in <NUM>, the UE may determine that the PRG size is equal to <NUM> of <NUM>, e.g., as configured by the RRC parameter bundleSizeSet1.

In a communication framework that utilizes a FDM scheme, it may be the case that physical resource blocks (PRBs) from the different TRPs should not be bundled. Effectively, the channels from the TRPs should be different. Thus, with respect to determining a PRB group bundling size, it may be preferable in such a scenario that a 'wideband' group size should not be indicated, or that a PDSCH block specific definition of a wideband group size should be used. More generally, it may be useful to provide a framework for indicating and determining PRB bundling size such that different PRB bundling sizes can be used for different TRPs. Accordingly, <FIG> is a flowchart diagram illustrating another possible scheme, e.g., as an alternative to the method of <FIG>, that may be used by a UE to determine the PRB bundling size for each PDSCH block of a multi-TRP downlink communication, according to some embodiments.

As shown, in <NUM>, the UE may determine if the RRC parameter prb-BundlingType is configured for the current PDSCH block. In <NUM>, if it is not, the UE may determine that a default PRB bundling size (e.g., <NUM> RBs, in the illustrated scenario) is configured for the current PDSCH block. In <NUM>, if the RRC parameter prb-BundlingType is configured, it may be determined if the prb-BundlingType parameter is set to dynamicBundling. If it is not, in <NUM>, the UE may determine that the PRB group size for the current PDSCH block is configured by the RRC parameter bundleSizeSet2 (e.g., which may be selected from an enumerated set of PRB bundle size options). In <NUM>, if the prb-BundlingType parameter is set to dynamicBundling, the UE may further determine if one value is configured in the RRC parameter bundleSizeSet1. If so, in <NUM>, the UE may determine the PRG size for the current PDSCH block based on the higher layer parameter bundleSizeSet1 (e.g., which may be selected from an enumerated set of PRB bundle size options). If not, in <NUM>, the UE may determine if the scheduled set of PRBs for the current PDSCH block is contiguous and if the number of scheduled PRBs for the current PDSCH block is above a threshold. If not, in <NUM>, the UE may determine that the PRG size for the current PDSCH block is wideband. If so, in <NUM>, the UE may determine that the PRG size for the current PDSCH block is equal to <NUM> of <NUM>, e.g., as configured by the RRC parameter bundleSizeSet1.

Thus, according to the method of <FIG>, the PRB bundling size can be determined by the scheduled RBs within each PDSCH block. In this scenario, 'wideband' may indicate that the PRB bundling is at a wideband level within a PDSCH block (e.g., and not necessarily across the entire multi-TRP downlink communication). For dynamic PRB bundling size selection, the 'scheduled set of PRBs' may refer to the number of RBs for the corresponding PDSCH block. The relevant RRC parameters could thus be configured on a per-PDSCH block basis, and the threshold used in step <NUM> could be configured by the network using RRC signaling, or could be predefined (e.g., as half of the maximum bandwidth of the active bandwidth part, as one possibility), among various options.

Using such an approach to determine a PRB bundling size separately for each PDSCH block from a different TRP, it may be possible that the PRB bundling size for each PDSCH block is different, e.g., as determined in accordance with the method of <FIG>, or using an alternative approach. Alternatively, if desired, the UE may determine a common PRB bundling size across all PDSCH blocks, e.g., after separately determining the (e.g., preliminary) PRB bundling size for each PDSCH block. For example, the common PRB bundling size could be determined as the maximum determined PRB bundling size among the configured PDSCH blocks (e.g., max (P1, P2,. , Pj), where Pj indicates the determined PRB bundling size for the PDSCH block j). As another possibility, the common PRB bundling size could be determined as the minimum determined PRB bundling size among the configured PDSCH blocks (e.g., min (P1, P2,.

Another potentially important aspect of configuring a FDM multi-TRP communication using a single DCI may include providing a mechanism for the UE to identify the frequency domain resource allocation for each PDSCH block. For example, <FIG> illustrates an exemplary possible frequency resource allocation for a FDM multi-TRP communication, in which a first PDSCH block from a first TRP may be allocated a first set of RBs (N_RB_1), while a second PDSCH block from a second TRP may be allocated a second set of RBs (N_RB_2).

As one possibility, a gNB providing DCI for a FDM multi-TRP communication may indicate two separate frequency domain resource allocations in the DCI, such that each frequency domain resource allocation indication corresponds to each PDSCH block.

As another possibility, a gNB providing DCI for a FDM multi-TRP communication may use a single frequency domain resource allocation indicator to configure the frequency resources for all of the PDSCH blocks in the DCI. Such a frequency domain resource allocation indicator could be defined in such a way as to specify the starting RB or RBG index and end RB or RBG index of each PDSCH block with a single indicator, for example using a combinatorial index. For example, <FIG> illustrates a scenario in which a first PDSCH block ("PDSCH block <NUM>") starts at RB S0 and ends at RB S1, while a second PDSCH block ("PDSCH block <NUM>") starts at RB S2 and ends at RB S3. Using such parameters, the value of the resource allocation field could be determined by a combinatorial index r that may be defined as follows: <MAT> where N is equal to the maximum number of RBs or RBGs within the active bandwidth part, and M is equal to <NUM>. Note that different combinatorial indices and/or different parameters could be used in conjunction with multi-TRP communications that include a different number (e.g., <NUM>, <NUM>, etc.) of PDSCH blocks.

Still another possible aspect of configuring a FDM multi-TRP communication using a single DCI may include providing a mechanism for the UE to determine the modulation and coding scheme (MCS) and RV for different PDSCH blocks. As one possible approach, the existing MCS/RV field for a second transport block may be used to configure a second PDSCH block. For example, 3GPP specification documents could include any or all of the following description (or similar description) regarding specifying the MCS/RV for multiple PDSCH blocks from different TRPs:.

As another possible approach, one MCS field may be used to indicate a common MCS for all PDSCH blocks, and only one RV indication (e.g., to indicate the RV for the first PDSCH block) may be provided. In this case, the RV for the second PDSCH block may be determined by the UE based at least in part on the RV for the first PDSCH block. For example, a specified relation between the RV for the first PDSCH block and the RV for the second PDSCH block may be used, such as RV2 = (RV1+<NUM>) mod <NUM>. If desired, the RV for the second PDSCH block may be determined based on the RV for the first PDSCH block as well as the resource allocation for the second PDSCH block, for example using the first PRB index for the second PDSCH block, or any of various other means may be used to specify a relation between the RV for the first PDSCH block and the RV for the second PDSCH block that allows the UE to determine the RV for each PDSCH block using one RV field of a DCI communication.

A further consideration with respect to configuring a FDM multi-TRP communication using a single DCI may include how to provide a framework that supports a UE dynamically determining the phase tracking reference signal (PT-RS) presence, density, and pattern associated with PDSCH blocks provided by different TRPs. For example, a current approach to determining the PT-RS frequency density for a PDSCH transmission may include using a table that maps scheduled bandwidth with PT-RS frequency density, such as illustrated in <FIG>. To adapt such an approach to be used in a scenario in which multiple PDSCH blocks provided by different TRPs are provided, it may be important to specify how to determine the PT-RS frequency density for each of the multiple PDSCH blocks.

As one possibility, one common PT-RS pattern may be transmitted associated with all of the PDSCH blocks. In such a case, the PT-RS frequency domain pattern may be selected based at least in part on any or all of: the number of resource blocks for one of the PDSCH blocks (e.g., one of N_RB_1, N_RB_2,. ); the minimum number of resource blocks among the PDSCH blocks (e.g., min(N_RB_1, N_RB_2,. )); the maximum number of resource blocks among the PDSCH blocks (e.g., max(N _RB_1, N_RB_2,. )); the total number of resource blocks among the PDSCH blocks (e.g., N _RB_1+N _RB_2+. ); or in any of various other ways. Additionally, in such a case, the PT-RS time domain patter may be selected based at least in part on the MCS(s) for the PDSCH blocks. For example, if the MCS is common across all PDSCH blocks, the PT-RS time domain pattern may be determined based using the indicated MCS. Otherwise, the PT-RS time domain pattern may be selected based on the minimum MCS among the PDSCH blocks (e.g., min(MCS_1, MCS_2,. )), the maximum MCS among the PDSCH blocks (e.g., max(MCS_1, MCS_2,. )), an equivalent MCS based on a combination of the MCS configurations (e.g., the MCS with spectral efficiency closest to an equivalent spectral efficiency calculated based on each of the MCS configurations), or in any of various other possible ways.

As another possibility, separate PT-RS patterns could be used for each PDSCH block. In such a scenario, the PD-RS dynamic presence and frequency/time domain pattern for each respective PDSCH block could be determined based on the scheduled RBs and MCS configuration for the respective PDSCH block.

For spatial division multiplexed operation, it may be useful to provide a mechanism for associating PT-RS and DMRS, at least according to some embodiments. For example, it may be the case that DMRS port combinations of <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, and <NUM>+<NUM> are supported, e.g., such that each PDSCH block may be associated with <NUM> or <NUM> DMRS ports. Since different TRPs could have different phase noise level properties, it may be preferable to map different PT-RS ports to different TRPs. One way to do so may include transmitting one independent PT-RS port associated with each PDSCH block, where the PT-RS port is associated with one DMRS port within each PDSCH block. The association may be specified in any of various possible ways. As one such possibility, the PT-RS port could be associated with the lowest DMRS port index within each PDSCH block. For example, in a scenario in which a UE is configured with a <NUM>+<NUM> DMRS port combination of {<NUM>; <NUM>,<NUM>}, the first PR-RS port may be associated with DMRS port <NUM>, while the second PT-RS port may be associated with DMRS port <NUM>. Alternative arrangements, such as associating the PT-RS port with the highest DMRS port index within each PDSCH block, or any of various other arrangements, are also possible. The dynamic presence and density of the PT-RS may be determined based on the scheduled RBs and MCS for each PDSCH block, at least according to some embodiments.

In some embodiments, a device (e.g., a UE <NUM> or BS <NUM>) may be configured to include a processor (or a set of processors) and a memory medium, where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method embodiments described herein (or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets). The device may be realized in any of various forms.

Claim 1:
A method, comprising:
by a wireless device (<NUM>):
receiving (<NUM>), from a first transmission reception point, TRP, of a plurality of TRPs, a downlink control information transmission scheduling a plurality of frequency division multiplexed, FDM, downlink transmissions from the plurality of TRPs;
determining physical resource block bundling sizes separately for the plurality of FDM downlink transmissions from the plurality of TRPs, wherein the determination is based on parameters comprising:
whether dynamic bundling is enabled; and
whether a number of the plurality of FDM downlink transmissions from the plurality of TRPs exceeds a threshold; and
receiving the plurality of FDM downlink transmissions from the plurality of TRPs in accordance with the downlink control information transmission (<NUM>) and the determined physical resource block bundling sizes.