Control signaling for uplink frequency selective precoding

Abstract

The present disclosure relates to control signaling for uplink frequency-selective precoding. Disclosed herein are systems and methods at a user equipment (UE) using control signaling for uplink frequency-selective precoding. A base station can indicate to a UE a transmission rank indicator (TRI), a wideband transmission precoder matrix indicator (TPMI), and one or more subband TPMIs. The base station can indicate to the UE whether to use the wideband TPMI or the subband TPMIs to precode a physical uplink shared channel (PUSCH) transmission from the UE to the base station. The UE then precodes (and transmits) the PUSCH accordingly. Methods of the UE applying the indicated subband TPMIs to subbands of the bandwidth in which the PUSCH can be transmitted are described. Methods of considering UE capabilities with respect to non-coherent, partial-coherent, and / or coherent precoding are described. Methods of assigning TPMIs to subbands taking into account multiple transmission reception points (TRPs) used by the UE for UE transmissions are described.

Description

TECHNICAL FIELD

[0001] The present application relates generally to wireless communication systems, including wireless communication systems that implement uplink frequency-selective precoding at a user equipment (UE). BACKGROUND

[0002] Wireless mobile communication technology uses various standards and protocols to transmit data between base stations and wireless communication devices. Wireless communication system standards and protocols can include, for example, the Third Generation Partnership Project (3GPP) Long-Term Evolution (LTE) (such as 4G), 3GPP New Radio (NR) (such as 5G), and IEEE 802.11 standards (commonly referred to as Wi-Fi® within the industry organization) for wireless local area networks (WLANs).

[0003] As contemplated by 3GPP, different wireless communication system standards and protocols can use various radio access networks (RANs) to enable base stations of the RAN (which can also be referred to at times as a RAN node, network node, or simply a node) to communicate with wireless communication devices referred to as user equipment (UE). 3GPP RANs can include, for example, Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and / or Next Generation Radio Access Network (NG-RAN).

[0004] Each RAN can use one or more radio access technologies (RATs) for communication between base stations and UEs. For example, GERAN implements GSM and / or EDGE RAT, UTRAN implements Universal Mobile Telecommunications System (UMTS) RAT or other 3GPP RAT, E-UTRAN implements LTE RAT (which is sometimes referred to simply as LTE), and NG-RAN implements NR RAT (which is sometimes referred to herein as a 5G RAT, 5G NR RAT, or simply NR). In certain deployments, E-UTRAN can also implement NR RAT. In certain deployments, NG-RAN can also implement LTE RAT.

[0005] A base station used by a RAN can correspond to that RAN. One example of an E-UTRAN base station is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (also denoted as an Evolved Node B, Enhanced Node B, eNodeB, or eNB). One example of an NG-RAN base station is a Next Generation Node B (sometimes also referred to as a gNodeB or gNB).

[0006] ​The RAN, through its connection to the core network (CN), together with the core network (CN), provides the communication service to external entities. For example, an E-UTRAN can utilize an Evolved Packet Core (EPC), while a NG-RAN can utilize a 5G Core (5GC). BRIEF DESCRIPTION OF DRAWINGS

[0007] To facilitate discussion, one or more of the most significant digits in a reference number refers to the drawing figure in which the element was first introduced.

[0008] Figure 1 A portion of a codebook corresponding to rank 3 transmission is shown in accordance with an embodiment.

[0009] Figure 2 A subband TPMI arrangement is shown in accordance with an embodiment.

[0010] Figure 3 A diagram showing use of wideband TPMI or subband TPMI corresponding to associated CORESETs is shown in accordance with an embodiment.

[0011] Figure 4 A method of a UE is shown in accordance with an embodiment.

[0012] Figure 5 A diagram showing use of subband TPMI when two-stage DCI is sent across linked search spaces is shown in accordance with an embodiment.

[0013] Figure 6 A diagram showing use of subband TPMI when two-stage DCI is sent across multiple CCE sets of SS is shown in accordance with an embodiment.

[0014] Figure 7 A method of a UE is shown in accordance with an embodiment.

[0015] Figure 8 A method of a base station is shown in accordance with an embodiment.

[0016] Figure 9 A diagram showing allocation of subband TPMI to various RBs is shown in accordance with an embodiment.

[0017] Figure 10 A diagram showing allocation of subband TPMI to various RBs is shown in accordance with an embodiment.

[0018] Figure 11 A method of a UE is shown in accordance with an embodiment.

[0019] Figure 12 A method of a UE is shown in accordance with an embodiment.

[0020] Figure 13A method of a base station according to an embodiment is shown.

[0021] Figure 14 A subband TPMI arrangement according to an embodiment is shown.

[0022] Figure 15 An exemplary architecture of a wireless communication system according to embodiments disclosed herein is shown.

[0023] Figure 16 A system for performing signaling between a wireless device and a network device according to embodiments disclosed herein is shown. DETAILED DESCRIPTION

[0024] Embodiments are described in terms of UEs. However, references to UEs are provided for illustrative purposes only. Exemplary embodiments can be used with any electronic component that can establish a connection with a network and is configured with hardware, software, and / or firmware for exchanging information and data with the network. Thus, a UE as described herein is used to represent any appropriate electronic component.

[0025] In some wireless communication systems, codebook-based precoding for uplink transmissions is supported for the case of transmissions by a UE to a single transmission reception point (TRP) (“single-TRP mode”) and to multiple TRPs (“multi-TRP mode”).

[0026] To facilitate UE transmissions according to the single-TRP mode, a base station can indicate to a UE each of a transmission rank indicator (TRI) and a transmission precoder matrix indicator (TPMI). The UE can then use the TRI to identify a set of precoder matrices that correspond to (for) a transmission rank indicated by or associated with the TRI. Further, the UE can use the provided TPMI to identify a particular precoder matrix (sometimes also referred to simply as a “precoder” herein) from the set. The UE can then use the assigned precoder to precode a corresponding uplink (UL) transmission (e.g., to be transmitted on a physical uplink shared channel (PUSCH)). In such cases, the precoder (e.g., the UL transmission precoder) can be used in a wideband manner (e.g., for any UL transmission over the entire scheduled bandwidth for such UL transmission).

[0027] To facilitate UE transmissions according to the multi-TRP mode, a base station can indicate a TRI, as described. In addition, a UE can indicate a TPMI for each TRP to which the UE will transmit in the multi-TRP mode. Each such TPMI can correspond to a precoder for a transmission direction between the UE and the respective TRP. Because the various TRPs can be in different transmission directions from the UE, the precoders can be different. The UE applies the precoder for each TRP to the PUSCH transmission to each TRP based on each TRP.

[0028] It is contemplated that, for PUSCH transmitted according to dynamic grant (DG), the TRI indication and the TPMI indication can be indicated by the downlink control information (DCI) that schedules the PUSCH. For PUSCH transmitted according to configured grant (CG), the TRI indication and the TPMI indication can be configured by radio resource control (RRC) so.

[0029] The codebook can contain precoders and can be used with the TRI indication and the TPMI indication to identify the appropriate precoder by the base station and / or at the UE. Figure 1 A portion 100 of a codebook corresponding to rank 3 transmissions according to an embodiment is shown. The portion 100 of the codebook is used when TRI = 3. In this codebook, there are seven precoders 102 available in the codebook with this TRI.

[0030] The UE can be capable of performing one or more of non-coherent precoding, partial-coherent precoding, and / or coherent precoding. In non-coherent precoding, the UE does not control phase alignment between any of the various UE antenna ports represented by the precoder. In partial-coherent precoding, the UE controls phase alignment between a subset of the various UE antenna ports (e.g., between pairs of antenna ports), but does not control phase alignment between the entire set of antenna ports. In coherent precoding, the UE controls phase alignment between the entire set of antenna ports. Controlling phase alignment between two or more antenna ports allows the UE to “divide” the rank across those “coherent” ports according to the precoder selected for the transmission. This can allow for the use of more complex precoders in the non-coherent case (and thus better control or tuning of the transmission direction used by the UE).

[0031] As shown, within the precoder 102, the first precoder 106 is a non-coherent precoder 120, the second precoder 108 and the third precoder 110 are partial-coherent precoders 122 (which implement phase alignment between the first antenna port and the third antenna port, making the second precoder 108 and the third precoder 110 more complex than the non-coherent precoder), and the fourth precoder 112, the fifth precoder 114, the sixth precoder 116, and the seventh precoder 118 are coherent precoders 124 (which utilize phase alignment between all four antenna ports), making the fourth precoder 112, the fifth precoder 114, the sixth precoder 116 more complex than the non-coherent precoder and the partial-coherent precoder. Each precoder in the precoder 102 corresponds to a TPMI index 104, which can be used to indicate (e.g., by the base station to the UE, as described above) one of the precoders 102.

[0032] In some cases, a UE can use non-coherent precoding. In other cases, a UE can use non-coherent precoding and / or partial-coherent precoding. In other cases, a UE can use non-coherent precoding, partial-coherent precoding, and / or coherent precoding. In any case, a UE can indicate its supported codebook types (e.g., supported precoder types) to a base station using UE capability signaling. The base station can then configure a codebook subset to the UE based on the UE’s capabilities using RRC signaling. For example, the base station can use a codebookSubset information element to indicate the properties of the codebook subset to the UE, maintaining a corresponding understanding of the codebooks used at the UE and the base station. Continuing the description, the codebook subset is used with the TRI / TPMI indication schemes discussed previously.

[0033] A UE can perform an UL transmission (e.g., a PUSCH transmission) over an allocated frequency bandwidth (e.g., bounded by a configured part (BWP)). In some cases, it can be that the UE is configured to use an allocated precoder for all such transmissions of the (entire) bandwidth. This can be understood as using a “wideband precoder”. A TPMI identifying a wideband precoder can be understood as a “wideband TPMI”.

[0034] However, it can be beneficial to support frequency-selective precoding within subbands of the (entire) bandwidth. For example, it can be that using a first precoder within a first subband and a second precoder within a second subband results in better overall throughput (e.g., due to specific, different channel conditions at each subband) than simply using the same precoder corresponding to each subband. This can be understood as the use of “subband precoders.” A TPMI that identifies a subband precoder (e.g., as corresponding to a given subband of the (entire) bandwidth) can be understood as a “subband TPMI.”

[0035] Figure 2 A subband TPMI configuration 200 is shown in accordance with embodiments. It is possible that a bandwidth 202 for an uplink (e.g., PUSCH) transmission by a UE is divided into a first subband 204, a second subband 206, an additional subband 208, an N-1th subband 210, and an Nth subband 212.

[0036] It is contemplated that a base station can indicate (in addition to TRI and wideband TPMI) a subband TPMI for each of one or more subbands 204-212 within the bandwidth 202. Each portion of a PUSCH scheduled to use the bandwidth 202 can then be precoded using a subband precoder identified by one of the subband TPMIs corresponding to the subband carrying that portion of the PUSCH.

[0037] With respect to the use of configured grants, it is possible that TRI, wideband TPMI, and / or subband TPMI are indicated to a UE in RRC. With respect to the use of dynamic grants, it is possible that TRI, wideband TPMI, and / or subband TPMI are indicated to a UE in DCI scheduling.

[0038] In some cases, it is possible that RRC configuration information can be used to indicate whether, for a PUSCH to be transmitted, a precoder corresponding to a wideband TPMI is to be used or multiple precoders corresponding to multiple subband TPMIs (corresponding to subbands used for transmission of the PUSCH) are to be used. In some embodiments, an RRC parameter can be used to enable / disable the use of subband TPMIs (as opposed to wideband TPMI). For example, an RRC parameter can be transmitted in a binary field to indicate whether a transmission should be precoded with a precoder corresponding to a subband TPMI or a wideband TPMI. In some embodiments, an RRC parameter can indicate a number of configured TPMIs. In these cases, when the value is 1, the UE should understand that the RRC configured TPMI is a wideband TPMI.

[0039] In some examples, a UE can apply use of a wideband TPMI or subband TPMI to transmissions within a particular BWP used by the UE in a manner configured by an RRC parameter. In some examples, a UE can apply use of a wideband TPMI or subband TPMI to transmissions to a particular serving cell in a manner configured by an RRC parameter. In some examples, a UE can apply use of a wideband TPMI or subband TPMI to transmissions between the UE and a particular serving cell group (SCG) in a manner configured by an RRC parameter. In some examples, a UE can apply use of a wideband TPMI or subband TPMI to all transmissions made by the UE in a manner configured by an RRC parameter.

[0040] In some examples, a UE can apply use of a wideband TPMI or subband TPMI to use of a particular control resource set (CORESET) in a manner configured by an RRC parameter. Figure 3 A diagram 300 illustrating use of a wideband TPMI or subband TPMI corresponding to an associated CORESET is shown in accordance with an embodiment. A first physical downlink control channel (PDCCH) 302 (e.g., DCI transmitted via the first PDCCH 302) scheduling a first PUSCH 304 is transmitted by a base station to a UE. The first PDCCH 302 can be received at the UE in a first CORESET. The first CORESET can correspond to a wideband TPMI (e.g., as configured by an RRC parameter). Accordingly, the UE precode the first PUSCH 304 scheduled by the first PDCCH 302 with a wideband precoder (the precoder identified by the wideband TPMI) prior to transmitting the first PUSCH 304.

[0041] A second PDCCH 306 (e.g., DCI via the second PDCCH 306) scheduling a second PUSCH 308 is transmitted by a base station to a UE. The second PDCCH 306 can be received at the UE in a second CORESET. The second CORESET can correspond to a subband TPMI (e.g., as configured by an RRC parameter). Accordingly, the UE precode the second PUSCH 308 scheduled by the second PDCCH 306 with a subband precoder (the precoder identified by the subband TPMI) prior to transmitting the second PUSCH 308, where each subband is used for transmission of the second PUSCH 308 using the corresponding subband precoder indicated by the corresponding subband TPMI.

[0042] In some examples, the UE can apply use of a wideband TPMI or a subband TPMI to a particular search space (SS) configured by an RRC parameter. For example, upon receiving a PDCCH that schedules a PUSCH, determining whether to use a wideband precoder (a precoder identified by a wideband TPMI) or a subband precoder (a precoder identified by a subband TPMI) to precode the PUSCH can be based on whether the PDCCH is received in a SS associated with use of the wideband TPMI or the subband TPMI, as configured by the RRC parameter.

[0043] In some cases, it can be possible to use medium access control control element (MAC CE) information to configure whether a transmission is precoded using a precoder corresponding to a wideband TPMI or a precoder corresponding to a subband TPMI for a PUSCH to be transmitted. For example, as described above, a MAC CE information can be transmitted in order to change or update a previous configuration by an RRC parameter. It can be possible that these MAC CE driven changes can be implemented faster compared to a change using a subsequent or updated RRC configuration.

[0044] Figure 4 A method 400 of a UE according to embodiments is shown. The method 400 includes receiving 402, from a base station, an RRC configuration including an indication that transmissions on a PUSCH should be precoded with a plurality of precoding matrices indicated by a plurality of TPMIs.

[0045] The method 400 also includes precoding 404 the transmissions using the plurality of precoding matrices indicated by the plurality of subband TPMIs.

[0046] The method 400 also includes transmitting 406 the transmissions on the PUSCH.

[0047] In some embodiments of the method 400, the indication that the transmissions should be precoded with the plurality of precoding matrices or a second precoding matrix indicated by a wideband TPMI is provided in a binary field.

[0048] In some embodiments of the method 400, the indication is provided as a plurality of TPMIs available for use at the UE.

[0049] In some embodiments of the method 400, the RRC configuration also identifies a bandwidth part (BWP) for which the indication that the transmissions should be precoded with the plurality of precoding matrices applies, and the PUSCH is transmitted in the BWP.

[0050] In some embodiments of the method 400, the RRC configuration also identifies a serving cell for which the indication that the transmissions should be precoded with the plurality of precoding matrices applies, and the PUSCH is transmitted on the serving cell.

[0051] In some embodiments of the method 400, the RRC configuration further identifies a group of serving cells to which the indication that the transmission should be precoded with the plurality of precoding matrices applies, and the PUSCH is transmitted on a cell in the group of serving cells.

[0052] In some embodiments of the method 400, the RRC configuration further identifies that the indication that the transmission should be precoded with the plurality of precoding matrices applies at the UE.

[0053] In some embodiments of the method 400, the RRC configuration further identifies a CORESET for which the indication that the transmission should be precoded with the plurality of precoding matrices applies, and the PDCCH scheduling the transmission is received in the CORESET.

[0054] In some embodiments of the method 400, the RRC configuration further identifies a SS for which the indication that the transmission should be precoded with the plurality of precoding matrices applies, and the PDCCH scheduling the transmission is received in the SS.

[0055] In some embodiments, the method 400 further includes receiving a MAC CE that updates the indication.

[0056] In some embodiments of the method 400, the plurality of subband TMPIs are provided in DCI scheduling the transmission.

[0057] In some embodiments of the method 400, the plurality of subband TMPIs are provided via RRC signaling.

[0058] In some embodiments of the method 400, the UE is capable of performing coherent transmission, and wherein the plurality of precoding matrices includes coherent precoding matrices.

[0059] In some embodiments of the method 400, the UE is capable of performing partial coherent transmission, and wherein the plurality of precoding matrices includes partial coherent precoding matrices.

[0060] In some embodiments of the method 400, the transmission is transmitted on a plurality of subbands corresponding to the plurality of subband TMPIs.

[0061] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 400. The apparatus can be, for example, an apparatus of a UE (such as the wireless device 1602 as a UE, as described herein).

[0062] Embodiments contemplated herein include one or more non-transitory computer- readable media comprising instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of method 400. The non-transitory computer-readable media can be, for example, a memory of a UE (such as memory 1606 of wireless device 1602 of a UE, as described herein).

[0063] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry to perform one or more elements of method 400. The apparatus can be, for example, an apparatus of a UE (such as wireless device 1602 of a UE, as described herein).

[0064] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of method 400. The apparatus can be, for example, an apparatus of a UE (such as wireless device 1602 of a UE, as described herein).

[0065] Embodiments contemplated herein include a signal as described in or related to one or more elements of method 400.

[0066] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processor causes the processor to perform one or more elements of method 400. The processor can be a processor of a UE (such as processor 1604 of wireless device 1602 of a UE, as described herein). The instructions can be, for example, located in the processor and / or on a memory of the UE (such as memory 1606 of wireless device 1602 of a UE, as described herein).

[0067] In some cases, it can be possible for DCI to indicate whether a precoder corresponding to a wideband TPMI or a precoder corresponding to a subband TPMI is to be used for a PUSCH scheduled by the DCI.

[0068] It is contemplated that there are cases in which DCI provides an indication of whether a wideband TPMI or a subband TPMI is used in the context of using two-stage DCI. In the case of two-stage DCI, it can be possible for a first stage DCI of the two-stage DCI to be used to provide a wideband TPMI (itself) to a UE as well as an indication of whether a wideband TPMI or a subband TPMI is used, and it can be possible for a second stage DCI of the two-stage DCI to be used to provide a subband TPMI to the UE.

[0069] In the corresponding two-stage DCI enforcement context, when receiving and starting to decode a DCI, the UE determines whether the decoded part of the DCI represents a first-stage DCI of a two-stage DCI. For example, the decoded part of the DCI can indicate that there is a second-stage DCI for the DCI. This can inform the UE that the (entire) DCI is a two-stage DCI, and thus the decoded part of the DCI is the first-stage DCI of this two-stage DCI. This first-stage DCI can include information for the UE that allows the UE to subsequently continue to locate and decode the second-stage DCI of the two-stage DCI.

[0070] Alternatively, it can be that when the UE receives and decodes the DCI, it determines that there is no second-stage DCI (thus, the DCI only includes a first-stage DCI and is not a two-stage DCI)

[0071] The use of wideband or subband TPMI can be triggered by the DCI accordingly by utilizing this context. For example, the UE can use the decoded first-stage DCI to determine whether a second-stage DCI exists. If a second-stage DCI exists, the UE uses the first-stage DCI to determine whether the subband precoder indicated by the subband TPMI of the second-stage DCI should be used to precode the PUSCH scheduled by the two-stage DCI (or whether the UE should instead precode the PUSCH using, for example, the wideband precoder for the wideband TPMI received in the first-stage DCI). The PUSCH is then precoded and transmitted accordingly. In the absence of a second-stage DCI, the wideband precoder indicated in the first-stage DCI can be used to precode the PUSCH.

[0072] In some embodiments, the first-stage DCI can include a field indicating whether a precoder corresponding to the wideband TPMI (provided by the first-stage DCI) or a precoder corresponding to the subband TPMI (provided by the second-stage DCI) should be used to precode the scheduled PUSCH. In some embodiments, this field can be a one-bit indicator provided in the first-stage DCI.

[0073] In some embodiments, the first-stage DCI can include a reserved value for a (e.g., existing) field of the DCI that indicates whether a precoder corresponding to the wideband TPMI (provided by the first-stage DCI) or a precoder corresponding to the subband TPMI (provided by the second-stage DCI) should be used to precode the scheduled PUSCH. In some embodiments, the reserved value can be a value of a demodulation reference signal (DMRS) antenna port indication found in the first-stage DCI.

[0074] In some embodiments, the first-stage DCI can be transmitted on a PDCCH with a starting control channel element (CCE) index that is associated with the use of a precoder corresponding to a wideband TPMI (provided by the first-stage DCI) or a precoder corresponding to a subband TPMI (provided by the second-stage DCI). In other words, the use of a wideband precoder or a subband precoder can open a determination made at the UE regarding the starting CCE index. In some cases, the determination can be a value relative to the starting CCE index. For example, if the starting CCE index is odd, the UE can use a subband precoder (identified by a subband TPMI), or if the starting CCE index is even, the UE can use a wideband precoder (identified by a wideband TPMI) (or vice versa).

[0075] In some embodiments, the first-stage DCI can be transmitted with cyclic redundancy check (CRC) bits that have been scrambled using a radio network temporary identifier (RNTI) that is configured to indicate the use of a precoder corresponding to a wideband TPMI (provided by the first-stage DCI) or a precoder corresponding to a subband TPMI (provided by the second-stage DCI). The RNTI can be referred to as a TPMI-C-RNTI. The RNTI can be associated with the PDCCH on which the DCI is transmitted. It can be that the UE determines to use a subband precoder (identified by a subband TPMI) if the CRC bits of the DCI have been scrambled using the RNTI, and / or determines to use a wideband precoder (identified by a wideband TPMI) if the CRC bits of the DCI have not been scrambled using the RNTI (or vice versa).

[0076] Note that because the wideband TPMI is transmitted in the first-stage DCI, it can be that the base station does not transmit the second-stage DCI in the case that the wideband TPMI (that has already been transmitted in the first-stage DCI) is to be used to precode the scheduled PUSCH. Thus, in this case, the first-stage DCI can not indicate the presence of the second-stage DCI. In this case, the UE can accordingly not attempt to decode the second-stage DCI.

[0077] In the case that the first-stage DCI indicates the presence of the second-stage DCI but the UE fails to decode the second-stage DCI, the UE can in some cases use the wideband precoder found in the first-stage DCI to precode the scheduled PUSCH and then transmit the scheduled PUSCH. Alternatively, the UE can in other such cases not transmit the scheduled PUSCH at all. Whether to use the wideband precoder or to discard the transmission of the PUSCH entirely in this case can be pre-defined at the UE and / or configured at the UE through higher layer signaling.

[0078] In some implementations, two levels of DCI can be transmitted within linked SSs. In this case, the first level DCI can be transmitted in the PDCCH of the first SS in the linked SSs, and the second level DCI can be transmitted in the PDCCH of the second SS in the linked SSs. The first SS (with the first level DCI) can be considered the primary SS, and the second SS (with the second level DCI) can be considered the secondary SS. The link and type (e.g., primary, secondary) of each such SS can be configured to the UE via RRC signaling or via MAC CE.

[0079] Figure 5 Figure 500 illustrates the use of subband TPMI when two-level DCIs are transmitted across the link search space, according to an implementation scheme. The first PDCCH 502 of the first SS is transmitted from the base station to the UE. The first PDCCH 502 may include a first-level DCI with scheduling information for PUSCH 506. This scheduling information may include the scheduling bandwidth of PUSCH 506. The UE can then compare the scheduling bandwidth with a threshold. The threshold may be predefined or may be configured by higher-layer signaling (e.g., RRC signaling or MAC CE).

[0080] If the UE determines that the scheduled bandwidth is below a threshold (not shown), the UE determines that there is no second-stage DCI, and the UE continues to precode the PUSCH using the wideband precoder identified from the first PDCCH by the wideband TPMI. This reflects the understanding that for relatively small bandwidths, PUSCH transmission is limited by an already relatively narrow frequency range, and the wideband TPMI found in the first-stage DCI accordingly provides a precoder that is sufficiently specific for that (relatively narrow) bandwidth.

[0081] In other cases (e.g.) Figure 5 As shown, when the UE determines that the scheduling bandwidth is equal to or greater than a threshold, the UE determines that a second-level DCI exists, and the UE should use the subband precoder indicated by the subband TPMI in the second-level DCI. Therefore, the UE continues to locate and decode the second-level DCI found on the second PDCCH 504 of the second SS, which is linked to the first SS of the first PDCCH 502. This second-level DCI may include the subband TPMI. The UE then continues to precode the PUSCH using the subband precoder identified by the subband TPMI and transmits the PUSCH.

[0082] A time offset (greater than a threshold) can be used between the first and second level DCI, so that the UE has enough time to decode the first PDCCH 502 with the first level DCI in the first SS (to learn of the existence of the second level DCI), and prepare to decode the second PDCCH 504 with the second level DCI in the second SS.

[0083] When the UE determines to use a wideband precoder with a wideband TPMI as described above, it can be possible that the UE does not include the secondary SS for blind detection (BD) / CCE counting. Alternatively, it can be possible that the UE always assumes that two level DCI is transmitted, and thus includes the secondary SS for the purpose of BD / CCE counting (even if the second level DCI in the secondary SS is not actually used).

[0084] It can be possible that if the primary SS is dropped (e.g., due to overbooking or quasi co-location (QCL) type D collision, etc.), the secondary SS should also be dropped.

[0085] When two level DCI is used across linked search spaces, a scheduling offset between the second PDCCH 504 and the PUSCH 506 can be used to ensure that the UE has enough time to decode the second PDCCH 504 and prepare to transmit the PUSCH 506 accordingly as described above. The scheduling offset can be determined according to the last symbol of the second PDCCH 504 in the secondary SS.

[0086] In some embodiments, two level DCI can be transmitted in a single SS, but across multiple CCE sets of the single SS. The SS can include a primary CCE set (PCCE) and a secondary CCE set (SCCE). In this case, the first level DCI can be transmitted in a first PDCCH of the PCCE of the SS, and the second level DCI can be transmitted in a second PDCCH of the SCCE of the SS. The PCCE and the SCCE can be 1:1 mapped, and any linkage between the PCCE and its corresponding PCCE can be configured by higher layer signaling or determined according to CCE set indices.

[0087] Figure 6 A diagram 600 showing the use of subband TPMI when two level DCI is transmitted across multiple CCE sets of a SS is shown, according to an embodiment. A first PDCCH 602 of a PCCE is transmitted by a base station to a UE. The first PDCCH 602 can include a first level DCI with scheduling information for a PUSCH 606. The scheduling information can include a scheduled bandwidth of the PUSCH 606. The UE can then compare the scheduled bandwidth to a threshold. The threshold can be predefined, or can be configured by higher layer signaling (e.g., RRC signaling or a MAC CE).

[0088] In the case where the UE determines that the scheduled bandwidth is below a threshold (not shown), the UE determines that there is no second stage DCI, and the UE continues to precode the PUSCH using the wideband precoder identified by the wideband TPMI from the first PDCCH. This can reflect the recognition that for a relatively small bandwidth, the transmission of the PUSCH is limited to a frequency range that is already relatively narrow, and the wideband TPMI found in the first stage DCI accordingly provides a precoder that is sufficiently specific to that (relatively narrow) bandwidth.

[0089] In other cases (as shown, for example, Figure 6 When the UE determines that the scheduled bandwidth is equal to or greater than the threshold, the UE determines that there is a second stage DCI, and the UE should use the subband precoder indicated by the subband TPMI in the second stage DCI. Accordingly, the UE continues to locate and decode the second stage DCI found on the second PDCCH 604 of the SCCE that is linked to the PCCE with the first PDCCH 602. This second stage DCI can include a subband TPMI. The UE then continues to precode the PUSCH using the subband precoder identified by the subband TPMI, and transmits the PUSCH.

[0090] When two-stage DCI is used across multiple CCE sets of an SS, a scheduling offset between the second PDCCH 604 and the PUSCH 606 can be used to ensure that the UE has sufficient time to decode the second PDCCH 604 and to prepare for transmission of the PUSCH 606 as described above accordingly. This scheduling offset can be determined from the last symbol of the second PDCCH 604 in the PCCE.

[0091] Figure 7 A method 700 of a UE according to an embodiment is shown. The method 700 includes decoding 702 a first stage DCI of a two-stage DCI received from a base station that schedules a transmission on a PUSCH.

[0092] The method 700 also includes determining 704, based on the first stage DCI, to precode the transmission using a plurality of precoding matrices indicated by a plurality of subband TPMIs of a second stage DCI of the two-stage DCI.

[0093] The method 700 also includes decoding 706 the second stage DCI of the two-stage DCI having the plurality of subband TPMIs.

[0094] The method 700 also includes precoding 708 the transmission using the plurality of precoding matrices indicated by the plurality of subband TPMIs.

[0095] The method 700 also includes transmitting 710 the transmission on the PUSCH.

[0096] In some embodiments of the method 700, determining, based on the first-stage DCI, to use the multiple precoding matrices indicated by the multiple-subband TPMI is based on a field of the first-stage DCI. In some of these embodiments, the field of the first-stage DCI is a one-bit indicator.

[0097] In some embodiments of the method 700, determining, based on the first-stage DCI, to use the multiple precoding matrices indicated by the multiple-subband TPMI is based on a reserved value of a field of the first-stage DCI. In some of these embodiments, the reserved value includes a value of a DMRS antenna port indication of the first-stage DCI.

[0098] In some embodiments of the method 700, determining, based on the first-stage DCI, to use the multiple precoding matrices indicated by the multiple-subband TPMI is based on a determination regarding a starting CCE index of a PDCCH carrying the first-stage DCI. In some of these embodiments, the determination regarding the starting CCE index is that the starting CCE index is odd.

[0099] In some embodiments of the method 700, determining, based on the first-stage DCI, to use the multiple precoding matrices indicated by the multiple-subband TPMI is based on an RNTI associated with a PDCCH carrying the first-stage DCI.

[0100] In some embodiments of the method 700, when the first-stage DCI is transmitted in a first SS and the second-stage DCI is transmitted in a second SS, determining, based on the first-stage DCI, to use the multiple precoding matrices indicated by the multiple-subband TPMI is based on a comparison of a scheduling bandwidth indicated by the first-stage DCI to a threshold.

[0101] In some embodiments of the method 700, when the first-stage DCI is transmitted in a PCCE of an SS and the second-stage DCI is transmitted in a SCCE of the SS, determining, based on the first-stage DCI, to use the multiple precoding matrices indicated by the multiple-subband TPMI is based on a comparison of a scheduling bandwidth indicated by the first-stage DCI to a threshold.

[0102] In some embodiments of the method 700, the UE is capable of performing coherent transmission, and wherein the multiple precoding matrices indicated by the multiple-subband TPMI include coherent precoding matrices.

[0103] In some embodiments of the method 700, the UE is capable of performing partial-coherent transmission, and wherein the multiple precoding matrices indicated by the multiple-subband TPMI include partial-coherent precoding matrices.

[0104] In some embodiments of the method 700, the first-stage DCI includes a wideband TPMI.

[0105] In some embodiments of the method 700, the transmission is transmitted on a plurality of subbands corresponding to a plurality of subband TPMIs.

[0106] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 700. The apparatus can be, for example, an apparatus of a UE, such as the wireless device 1602 as a UE, as described herein.

[0107] Embodiments contemplated herein include one or more non-transitory computer- readable media comprising instructions to, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of the method 700. The non-transitory computer-readable media can be, for example, a memory of a UE, such as the memory 1606 of the wireless device 1602 as a UE, as described herein.

[0108] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of the method 700. The apparatus can be, for example, an apparatus of a UE, such as the wireless device 1602 as a UE, as described herein.

[0109] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions to, when executed by the one or more processors, cause the one or more processors to perform one or more elements of the method 700. The apparatus can be, for example, an apparatus of a UE, such as the wireless device 1602 as a UE, as described herein.

[0110] Embodiments contemplated herein include a signal as described in or related to one or more elements of the method 700.

[0111] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processor causes the processor to perform one or more elements of the method 700. The processor can be a processor of a UE, such as the processor 1604 of the wireless device 1602 as a UE, as described herein. The instructions can be, for example, located within the processor and / or on a memory of the UE, such as the memory 1606 of the wireless device 1602 as a UE, as described herein.

[0112] Figure 8A method 800 of a base station is shown in accordance with embodiments. The method 800 includes transmitting 802, to a UE, a first stage DCI of a two-stage DCI scheduling a transmission on a PUSCH, where the first stage DCI is configured to indicate that a plurality of precoding matrices indicated by a plurality of subband TMPIs of the second stage DCI of the two-stage DCI are to be used to precoding the transmission.

[0113] The method 800 also includes transmitting 804, to the UE, the second stage DCI with the plurality of subband TMPIs.

[0114] The method 800 also includes receiving 806, from the UE, the transmission on the PUSCH that has been precoded using the plurality of precoding matrices indicated by the plurality of subband TMPIs.

[0115] In some embodiments of the method 800, the first stage DCI is configured to indicate that the plurality of precoding matrices indicated by the plurality of subband TMPIs are to be used via a field of the first stage DCI. In some of these embodiments, the field of the first stage DCI is a 1-bit indicator.

[0116] In some embodiments of the method 800, the first stage DCI is configured to indicate that the plurality of precoding matrices indicated by the plurality of subband TMPIs are to be used via a reserved value of a field of the first stage DCI. In some of these embodiments, the reserved value includes a value of a DMRS antenna port indication of the first stage DCI.

[0117] In some embodiments of the method 800, the first stage DCI is configured to indicate that the plurality of precoding matrices indicated by the plurality of subband TMPIs are to be used by being transmitted in a PDCCH having a starting CCE index corresponding to the use of the plurality of subband TMPIs. In some of these embodiments, the starting CCE index corresponds to the use of the plurality of subband TMPIs because the starting CCE index is odd.

[0118] In some embodiments of the method 800, the first stage DCI is configured to indicate that the plurality of precoding matrices indicated by the plurality of subband TMPIs are to be used by being transmitted in a PDCCH associated with an RNTI corresponding to the use of the plurality of subband TMPIs.

[0119] In some embodiments of the method 800, when the first stage DCI is transmitted in a first SS and the second stage DCI is transmitted in a second SS, the first stage DCI is configured to indicate that the plurality of precoding matrices indicated by the plurality of subband TMPIs are to be used via a scheduling bandwidth indicated by the first stage DCI.

[0120] In some embodiments of the method 800, when the first-stage DCI is transmitted in a PCCE of a search space (SS) and the second-stage DCI is transmitted in a SCCE of the SS, the first-stage DCI is configured to indicate to use the multiple precoding matrices indicated by the multiple subband TPMIs via a scheduling bandwidth indicated by the first-stage DCI.

[0121] In some embodiments of the method 800, the UE is capable of performing coherent transmission, and wherein the multiple precoding matrices indicated by the multiple subband TPMIs include coherent precoding matrices.

[0122] In some embodiments of the method 800, the UE is capable of performing partial coherent transmission, and wherein the multiple precoding matrices indicated by the multiple subband TPMIs include partial coherent precoding matrices.

[0123] In some embodiments of the method 800, the first-stage DCI includes a wideband TPMI.

[0124] In some embodiments of the method 800, the transmission is received on multiple subbands corresponding to the multiple subband TPMIs.

[0125] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 800. For example, the apparatus can be an apparatus of a base station, such as network equipment 1618 as a base station, as described herein.

[0126] Embodiments contemplated herein include one or more non-transitory computer- readable media comprising instructions to, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of the method 800. For example, the non-transitory computer-readable media can be a memory of a base station, such as memory 1622 of network equipment 1618 as a base station, as described herein.

[0127] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of the method 800. For example, the apparatus can be an apparatus of a base station, such as network equipment 1618 as a base station, as described herein.

[0128] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions to, when executed by the one or more processors, cause the one or more processors to perform one or more elements of the method 800. For example, the apparatus can be an apparatus of a base station, such as network equipment 1618 as a base station, as described herein.

[0129] Embodiments contemplated herein include a signal as described in or related to one or more elements of method 800.

[0130] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processing element causes the processing element to carry out one or more elements of method 800. The processor can be a processor of a base station (such as processor 1620 of network device 1618 of a base station, as described herein). For example, the instructions can be located within the processor and / or on a memory of the base station (such as memory 1622 of network device 1618 of a base station, as described herein).

[0131] In some embodiments, the nature of the wideband TPMI / subband TPMI operation can be determined relative to the scheduled bandwidth provided by the base station. For example, assume X resource blocks (RBs) are scheduled by the base station, and N subband TPMIs are also indicated by the base station.

[0132] In a first case, it can be that a threshold T (denoting a threshold of a number of RBs) is used at the UE. T can be predefined at the UE, or can be configured to the UE through higher layer signaling. Then, if X > T, the indicated subband TMPIs are used at the UE to identify the precoder for (parts of) the transmission within the scheduled RBs (according to the corresponding subband). In this case, the UE iterates through each of the N subband TPMIs with respect to the X RBs, where the nthsubband TPMI is applied to each ceil(X / N) or floor(X / N) of the X RBs (in case of uneven division of X / N, the last subband TPMI is applied to all remaining RBs that are not applied to at the last iteration).

[0133] Otherwise, if X ≤ T, the wideband TPMI is used to identify a wideband precoder for all transmissions within the corresponding frequency range.

[0134] Figure 9 A diagram 900 showing allocation of subband TPMIs to various RBs is shown in accordance with an embodiment. In this example, the base station schedules 4 RBs (RB0, RB1, RB2, RB3) and indicates 3 subband TPMIs (TPMI0, TPMI1, TPMI2). The base station indicates TPMI0 for RB0, TPMI1 for RB1, and TPMI2 for RB2 and RB3. The UE then iterates through each of the 3 subband TPMIs with respect to the 4 RBs, where the nthsubband TPMI is applied to each ceil(4 / N) or floor(4 / N) of the 4 RBs (in case of uneven division of 4 / N, the last subband TPMI is applied to all remaining RBs that are not applied to at the last iteration). Figure 9In the illustrated embodiment, X = 10 and N = 4. The UE first determines that X > T (e.g., that the scheduled 10 RBs exceed the threshold of RBs using a subband TPMI known to the UE). The UE then iterates through each of the 4 subband TPMIs with respect to the 10 RBs, assigning one of them to ceil(10 / 4) = 3 (as many as possible) of the scheduled RBs during each iteration. Thus, as illustrated, the UE assigns the first subband TPMI to the first subband 902 with first RB 910, second RB 912, and third RB 914; the second subband TPMI to the second subband 904 consisting of fourth RB 916, fifth RB 918, and sixth RB 920; the third subband TPMI to the third RB subband 906 consisting of seventh RB 922, eighth RB 924, and ninth RB 926; and the fourth subband TPMI to the fourth subband 908 consisting of tenth RB 928 (and note that there are no more RBs to assign, so this fourth subband 908 has less than three RBs).

[0135] In a second case, it can be that a subband size (in RBs) K is configured to the UE through higher layer signaling. The UE then iterates through each of the N subband TPMIs with respect to the X RBs, where the nth subband TPMI is applied to every K of the X RBs. In the case that X > N*K, once all N subband TPMIs have been assigned in this manner, there will be unassigned (remaining) RBs. In this case, a wideband TPMI can be assigned to the remaining RBs. In the case that X < N*K, it can be that one or more subband TPMIs are not fully used over K RBs. Further, it can also be that only the subband TPMIs corresponding to the RBs scheduled according to the assignment method are actually assigned to those corresponding RBs (e.g., it can be that one or more subband TPMIs are not actually assigned to one or more RBs).

[0136] Figure 10 A diagram 1000 illustrating assignment of subband TPMIs to various RBs is shown in accordance with an embodiment. In this example, X = 10 and N = 4. The UE first determines that X > T (e.g., that the scheduled 10 RBs exceed the threshold of RBs using a subband TPMI known to the UE). The UE then iterates through each of the 4 subband TPMIs with respect to the 10 RBs, assigning one of them to ceil(10 / 4) = 3 (as many as possible) of the scheduled RBs during each iteration. Thus, as illustrated, the UE assigns the first subband TPMI to the first subband 902 with first RB 910, second RB 912, and third RB 914; the second subband TPMI to the second subband 904 consisting of fourth RB 916, fifth RB 918, and sixth RB 920; the third subband TPMI to the third RB subband 906 consisting of seventh RB 922, eighth RB 924, and ninth RB 926; and the fourth subband TPMI to the fourth subband 908 consisting of tenth RB 928 (and note that there are no more RBs to assign, so this fourth subband 908 has less than three RBs). Figure 10In the illustrated embodiment, X = 10, N = 4, and K = 2. The UE iterates through each of the 4 subband TPMIs with respect to the 10 RBs, assigning one of them to K = 2 of the scheduled RBs during each iteration. Thus, as illustrated, the UE assigns the first subband TPMI to the first subband 1002 with first RB 1012 and second RB 1014; the second subband TPMI to the second subband 1004 consisting of third RB 1016 and fourth RB 1018; the third subband TPMI to the third RB subband 1006 consisting of fifth RB 1020 and sixth RB 1022; and the fourth subband TPMI to the fourth subband 1008 consisting of seventh RB 1024 and eighth RB 1026.

[0137] Because X > N*K in this case, once the iteration through the N TPMIs is complete, the fourth subband TPMI is assigned to the fourth subband 1008, leaving the remaining RBs (ninth RB 1028 and tenth RB 1030). Thus, a wideband TPMI is assigned to the fifth subband 1010 with the remaining ninth RB 1028 and tenth RB 1030.

[0138] Figure 11 A method 1100 of a UE according to an embodiment is shown. The method 1100 includes determining 1102 a number X of RBs available in a scheduled bandwidth of the UE.

[0139] The method 1100 also includes receiving 1104, at the UE, a plurality of subband TPMIs, where a number of the subband TPMIs is N.

[0140] The method 1100 also includes determining 1106 to precode transmissions on a PUSCH using a plurality of precoding matrices identified by the plurality of subband TPMIs based on the number X of RBs.

[0141] The method 1100 also includes identifying 1108 a plurality of subbands of the PUSCH corresponding to the plurality of subband TPMIs, each subband comprising a subset of the RBs, based on the number N of the plurality of subband TPMIs and the number X of RBs.

[0142] The method 1100 also includes precoding 1110 the transmissions using the plurality of precoding matrices indicated by the plurality of subband TPMIs.

[0143] The method 1100 also includes transmitting 1112 the transmissions on the PUSCH.

[0144] In some embodiments of the method 1100, the determining to use the precoding matrix to identify the plurality of subbands TMPI is performed when the number of RBs X is greater than a threshold. In some of these embodiments, the subset of RBs of at least one of the plurality of subbands is equal to one of ceil(X / N) RBs and floor(X / N) RBs.

[0145] In some embodiments, the method 1100 further includes receiving a subband size K RBs, where the subset of RBs of at least one of the plurality of subbands is equal to K RBs.

[0146] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 1100. The apparatus can be, for example, an apparatus of a UE (such as the wireless device 1602 as a UE, as described herein).

[0147] Embodiments contemplated herein include one or more non-transitory computer- readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of the method 1100. The non-transitory computer-readable medium can be, for example, a memory of a UE (such as the memory 1606 of the wireless device 1602 as a UE, as described herein).

[0148] Embodiments contemplated herein include an apparatus comprising logic, a module, or a circuit for performing one or more elements of the method 1100. The apparatus can be, for example, an apparatus of a UE (such as the wireless device 1602 as a UE, as described herein).

[0149] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions to cause the one or more processors, upon execution of the instructions, to perform one or more elements of the method 1100. The apparatus can be, for example, an apparatus of a UE (such as the wireless device 1602 as a UE, as described herein).

[0150] Embodiments contemplated herein include a signal as described in or related to one or more elements of the method 1100.

[0151] The embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein an execution program by a processor causes the processor to perform one or more elements of method 1100. The processor may be a processor of the UE (such as processor 1604 as a wireless device 1602 of the UE, as described herein). These instructions may, for example, reside in the processor and / or in the memory of the UE (such as memory 1606 as a wireless device 1602 of the UE, as described herein).

[0152] In some implementations, the use of subband precoders and / or subband TPMI indicators may depend on the UE's capabilities regarding incoherent, partially coherent, and / or coherent transmissions.

[0153] For example, in the first case, the subband TPMI indicated by the base station may correspond to a codebook subset with a phase interference encoder. Therefore, it is possible that the subband TPMI is only indicated to the UE if the UE is capable of coherent transmission. It is also possible that the base station may indicate candidate values ​​for representing the codebook subset, allowing the UE to identify the candidate values ​​of the codebook subset being used (e.g., allowing the UE to identify the intended phase interference encoder using the same codebook subset as the base station with the provided TPMI).

[0154] In some such cases, it is possible that the UE can also perform partially coherent transmissions, and some TPMIs using a partially coherent encoder with more than a threshold X antenna ports can also be used in a codebook subset from which subband TPMIs are extracted (where, for example, X = 2 or X = 4, and can be predefined based on performance test data). This lower limit of X helps ensure that the precoder used corresponds to a sufficiently narrow beam (to ensure sufficient performance gain to offset the computational cost of using such a precoder).

[0155] For UEs that cannot support coherent transmission (e.g., can only support non-coherent and / or partially coherent transmission), it is possible that the base station indicates a wideband TPMI for UL (e.g., PUSCH) transmission.

[0156] In the second scenario, it is possible that the subband TPMI indicated by the base station could correspond to a codebook subset that includes phase interference encoders and partially phase interference encoders. Therefore, it is possible that the subband TPMI is only indicated to the UE if the UE is capable of coherent and / or partially coherent transmission. It is also possible that the base station can indicate candidate values ​​for representing the codebook subset, allowing the UE to identify the codebook subset in use (e.g., allowing the UE to use the same codebook subset as the base station with the provided TPMI to identify the intended phase interference encoder and partially phase interference encoder).

[0157] The partially-coherent precoders included in the codebook subset can be precoders having more than X number of non-zero-power (NZP) antenna ports for at least one layer of the precoder, or having more than X number of non-zero-power (NZP) antenna ports for each layer of the precoder.

[0158] For UEs that cannot support coherent or partially-coherent transmission (e.g., can only support non-coherent transmission), it can be possible for the base station to indicate a wideband TPMI for UL transmission.

[0159] Figure 12 A method 1200 of a UE is shown in accordance with embodiments. The method 1200 includes determining 1202 a set of subband TPMIs of precoding matrices corresponding to a codebook subset of a codebook, where the codebook subset excludes non-coherent precoding matrices of the codebook.

[0160] The method 1200 also includes selecting 1204, using the multiple subband TPMIs in the set of subband TPMIs, multiple precoding matrices from the codebook subset for precoding a transmission on a PUSCH.

[0161] The method 1200 also includes precoding 1206 the transmission using the multiple precoding matrices selected with the multiple subband TPMIs.

[0162] The method 1200 also includes transmitting 1208 the transmission on the PUSCH.

[0163] In some embodiments of the method 1200, the codebook subset includes only coherent precoding matrices.

[0164] In some embodiments of the method 1200, the codebook subset includes partially-coherent precoding matrices and coherent precoding matrices of the codebook. In some of these embodiments, each of the partially-coherent precoding matrices uses a number of antenna ports that is greater than a threshold. In some of these embodiments, each of the partially-coherent precoding matrices has more than a threshold amount of non-zero-power (NZP) antenna ports for at least one layer of the respective precoding matrix. In some of these embodiments, each of the partially-coherent precoding matrices has more than a threshold amount of non-zero-power (NZP) antenna ports for each layer of the respective precoding matrix.

[0165] In some embodiments, the method 1200 also includes receiving an indication from a base station, the indication informing the UE that the codebook subset includes coherent precoders. In some of these embodiments, the indication also informs the UE that the codebook includes partially-coherent precoders.

[0166] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of method 1200. The apparatus can be, for example, an apparatus of a UE, such as wireless device 1602 as a UE, as described herein.

[0167] Embodiments contemplated herein include one or more non-transitory computer- readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of method 1200. The non-transitory computer-readable medium can be, for example, a memory of a UE, such as memory 1606 of wireless device 1602 as a UE, as described herein.

[0168] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of method 1200. The apparatus can be, for example, an apparatus of a UE, such as wireless device 1602 as a UE, as described herein.

[0169] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions to cause the one or more processors, upon execution of the instructions by the one or more processors, to perform one or more elements of method 1200. The apparatus can be, for example, an apparatus of a UE, such as wireless device 1602 as a UE, as described herein.

[0170] Embodiments contemplated herein include a signal as described in or related to one or more elements of method 1200.

[0171] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processor causes the processor to perform one or more elements of method 1200. The processor can be a processor of a UE, such as processor 1604 of wireless device 1602 as a UE, as described herein. The instructions can be, for example, located in the processor and / or on a memory of the UE, such as memory 1606 of wireless device 1602 as a UE, as described herein.

[0172] Figure 13 A method 1300 of a base station, in accordance with embodiments, is shown. The method 1300 includes transmitting 1302 an indication to a UE, the indication informing the UE of a codebook subset of a codebook, wherein precoding matrices of the codebook subset correspond to a set of subband TPMIs, and wherein the codebook subset excludes non-coherent precoding matrices of the codebook.

[0173] The method 1300 also includes receiving 1304, from the UE, a transmission on a PUSCH that has been precoded using a plurality of precoding matrices corresponding to a plurality of TPMIs in the set of subband TPMIs.

[0174] In some embodiments of the method 1300, the subset of codebooks includes only coherent precoding matrices.

[0175] In some embodiments of the method 1300, the subset of codebooks includes partial-coherent precoding matrices and coherent precoding matrices of the codebook. In some of these embodiments, each of the partial-coherent precoding matrices uses a number of antenna ports that is greater than a threshold. In some of these embodiments, each of the partial-coherent precoding matrices has a number of non-zero power (NZP) antenna ports for at least one layer of the respective precoding matrix that is greater than a threshold amount. In some of these embodiments, each of the partial-coherent precoding matrices has a number of non-zero power (NZP) antenna ports for each layer of the respective precoding matrix that is greater than a threshold amount.

[0176] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 1300. For example, the apparatus can be an apparatus of a base station, such as network equipment 1618 as a base station, as described herein.

[0177] Embodiments contemplated herein include one or more non-transitory computer- readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of the method 1300. For example, the non-transitory computer-readable medium can be a memory of a base station, such as memory 1622 of network equipment 1618 as a base station, as described herein.

[0178] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of the method 1300. For example, the apparatus can be an apparatus of a base station, such as network equipment 1618 as a base station, as described herein.

[0179] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions to cause the one or more processors to perform one or more elements of the method 1300 when executed by the one or more processors. For example, the apparatus can be an apparatus of a base station, such as network equipment 1618 as a base station, as described herein.

[0180] Embodiments contemplated herein include a signal as described in or related to one or more elements of the method 1300.

[0181] Embodiments contemplated herein include a computer program or computer program product comprising instructions, where execution of the program by a processing element causes the processing element to carry out one or more elements of the method 1300. The processor can be a processor of a base station (such as the processor 1620 of the network device 1618 of the base station, as described herein). For example, the instructions can be located within the processor and / or on a memory of the base station (such as the memory 1622 of the network device 1618 of the base station, as described herein).

[0182] It is contemplated that in some cases, the UE can be involved in multi-TRP transmission. Accordingly, methods of frequency-selective precoding are discussed in terms of possible multi-TRP transmission.

[0183] In a first option, it is possible that frequency-selective precoding is used only when the UE performs single-TRP transmission. In other words, it is possible that the UE does not use frequency-selective precoding in the context of multi-TRP transmission by the UE.

[0184] In a second option, it is possible that frequency-selective precoding is used for UEs performing multi-TRP transmission. In this case, it is possible that the use of wideband TPMI and / or the use of subband TPMI is configured on a per-TRP or across-TRP basis (e.g., using RRC configuration information or DCI to indicate whether a precoder corresponding to wideband TPMI or a precoder corresponding to subband TPMI is to be used for a PUSCH to be transmitted, as described herein).

[0185] For example, in some such cases, the DCI can indicate M*N subband TPMIs, where M is the number of TRPs in the multi-TRP transmission in which operation based on subband TPMI is enabled (e.g., as described herein), and N is the number of subband TPMIs per TRP. When two-level DCI based operation is used, the second level DCI can provide the indication of subband TPMIs for the multiple (e.g., two, all, etc.) TRPs that are being used.

[0186] Figure 14 A subband TPMI configuration 1400 is shown in accordance with an embodiment. It is possible that a bandwidth 1402 for uplink (e.g., PUSCH) transmission is divided into a first subband 1404, a second subband 1406, an additional subband 1408, an N-1th subband 1410, and an Nth subband 1412.

[0187] Using the above, a method of frequency-selective precoding is shown in accordance with an embodiment. Figure 14A UE configured with the subband TPMI configuration 1400 can be configured to transmit to a pair of TRPs. Thus, it is contemplated that the base station can indicate a per-TRP subband TPMI for each of the first subband 1404, the second subband 1406, the additional subbands 1408, the N-lth subband 1410, and / or the Nth subband 1412. Thus, as shown, the base station can then configure the UE with a first set of subband TPMIs 1414 to determine a first set of subband precoders for PUSCH transmissions to a first TRP, and / or can further configure the UE with a second set of subband TPMIs 1416 to determine a second set of subband precoders for PUSCH transmissions to a second TRP.

[0188] Figure 15 An exemplary architecture of a wireless communication system 1500 is shown in accordance with the embodiments disclosed herein. The description provided below is directed to an exemplary wireless communication system 1500 that operates in conjunction with the LTE system standards and / or 5G or NR system standards provided by 3GPP Technical Specifications.

[0189] As Figure 15 shown, the wireless communication system 1500 includes UE 1502 and UE 1504 (although any number of UEs can be used). In this example, the UEs 1502 and 1504 are shown as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks) but can also include any mobile or non-mobile computing device configured for wireless communication.

[0190] The UEs 1502 and 1504 can be configured to communicate using the cellular band, the unlicensed band, or a combination thereof. The UEs 1502 and 1504 can be configured to communicate using separate transmit and receive chains, or a single transmit and receive chain.

[0191] In this example, the connections 1508 and 1510 are air interfaces that implement the wireless communication between the UEs 1502 and 1504 and the RAN 1506. Each of the connections 1508 and 1510 include a physical layer interface that can be the same or different. Each of the connections 1508 and 1510 include a physical layer interface that can be the same or different. The connections 1508 and 1510 are illustrated as an air interface to facilitate 3GPP

[0192] In some embodiments, UEs 1502 and 1504 can also be configured to directly exchange communication data via a sidelink interface 1516. The UE 1504 is illustrated as being configured to access an access point (AP) 1518 via a connection 1520. In the example, the connection 1520 can comprise a local wireless connection, such as a connection consistent with any IEEE 1002.11 protocol, Bluetooth connection, and / or any other suitable connection. In another example, the connection 1520 can comprise a non-local connection, such as a wide area wireline or wireless connection (e.g., via an API 1524). In another embodiment, the UE 1504 can access the AP 1518 via a connection 1522, such as a connection consistent with any IEEE 1002.11 protocol, a Bluetooth connection, and / or any other suitable connection. The AP 1518 can or can not be connected to a core network (e.g., the CN 1524). In the example shown, the AP 1518 can not be connected to the CN 1524. In some embodiments, the AP 1518 can be a wireless AP, such as a wireless AP configured to communicate according to any IEEE 1002.11 protocol, a Bluetooth AP, and / or any other suitable wireless protocol.

[0193] In embodiments, the UEs 1502 and 1504 can be configured to communicate using one or more communication technologies, such as, but not limited to, orthogonal frequency division multiplexing (OFDM) communication signals with frequency division duplexing (FDD), time division duplexing (TDD), and / or a combination of FDD and TDD. OFDM signals can comprise a plurality of orthogonal subcarriers.

[0194] In some embodiments, all or a portion of base station 1512 or base station 1514 can be implemented as one or more software entities running on server computers as part of a virtual network. Additionally, or in other embodiments, base station 1512 or base station 1514 can be configured to communicate with each other via interface 1522. In embodiments where the wireless communication system 1500 is an LTE system (e.g., where CN 1524 is an EPC), interface 1522 can be an X2 interface. The X2 interface can be defined between two or more base stations (e.g., two or more eNBs, etc.) that connect to a EPC or between two eNBs that connect to a EPC. In embodiments where the wireless communication system 1500 is a NR system (e.g., where CN 1524 is a 5GC), interface 1522 can be an Xn interface. The Xn interface is defined between two or more base stations (e.g., two or more gNBs, etc.) that connect to a 5GC, between a base station 1512 (e.g., gNB) and an eNB that connect to a 5GC, and / or between two eNBs that connect to a 5GC (e.g., CN 1524).

[0195] The RAN 1506 is shown to include base stations 1512 and 1514, which provide wireless access to the core network 1524 for UEs 1502 and 1504, respectively. The base stations 1512, 1514 can be referred to as NodeBs, evolved NodeBs (eNBs), gNBs, RAN nodes, radio heads, or transmission reception points (TRPs), among other examples. The UEs 1502, 1504 can be referred to as mobile stations, subscriber stations, mobile units, subscriber

[0196] In embodiments, the CN 1524 can be an EPC, and the RAN 1506 can interface with the CN 1524 via an S1 interface 1528. In embodiments, the S1 interface 1528 can be split into two parts, an S1 user plane (S1-U) interface, which carries traffic data between the base stations 1512, 1514 and serving gateways (S-GWs) 1530, and an S1-MME interface, which is a signaling interface between the base stations 1512, 1514 and mobility management entities (MMEs) 1532.

[0197] In embodiments, the CN 1524 can be a 5GC, and the RAN 1506 can interface with the CN 1524 via an NG interface 1528. In embodiments, the NG interface 1528 can be split into two parts, an NG user plane (NG-U) interface, which carries traffic data between the base stations 1512, 1514 and user plane functions (UPFs) 1530, and an S1 control plane (NG-C) interface, which is a signaling interface between the base stations 1512, 1514 and access and mobility management functions (AMFs) 1532.

[0198] Generally, the application server 1530 can be an element of a network that provides content, or access to content, to UEs 1502, 1504 using Internet Protocol (IP) bearers provided by the CN 1524. The application server 1530 can also be configured to support one or more communication services (e.g., VoIP sessions, group communication sessions, or the like) for the UEs 1502, 1504 via the CN 1524. The application server 1530 can communicate with the CN 1524 through an IP communications interface 1532.

[0199] Figure 16 A system 1600 for performing signaling 1634 between a wireless device 1602 and a network device 1618 is shown, in accordance with the embodiments disclosed herein. The system 1600 can be part of a wireless communication system, as described herein. The wireless device 1602 can be, for example, a UE of the wireless communication system. The network device 1618 can be, for example, a base station (e.g., an eNB or gNB) of the wireless communication system.

[0200] The wireless device 1602 can include one or more processors 1604. The processors 1604 can execute instructions to perform various operations of the wireless device 1602, as described herein. The processors 1604 can include one or more baseband processors implemented with, for example, a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0201] The wireless device 1602 can include a memory 1606. The memory 1606 can be a non-transitory computer-readable storage medium that stores instructions 1608 (which can include, for example, computer program instructions executed by the processors 1604). The instructions 1608 can also be referred to as program code or computer programs. The memory 1606 can also store data used by the processors 1604 and results of operations performed by the processors.

[0202] The wireless device 1602 can include one or more transceivers 1610, which can include radio frequency (RF) transmitter and / or receiver circuits that use the antennas 1612 of the wireless device 1602 to facilitate transmission or reception of signaling (e.g., signaling 1634) by the wireless device 1602 with other devices (e.g., network devices 1618) in accordance with a corresponding RAT.

[0203] The wireless device 1602 can include one or more antennas 1612 (e.g., one, two, four, or more). For embodiments with multiple antennas 1612, the wireless device 1602 can take advantage of spatial diversity of such multiple antennas 1612 to send and / or receive multiple different data streams on the same time-frequency resources. This approach can be referred to as, for example, a multiple-input multiple-output (MIMO) approach (referring to the multiple antennas used in this regard at the transmitting device and the receiving device sides, respectively). MIMO transmission by the wireless device 1602 can be implemented according to pre-coding (or digital beamforming) applied at the wireless device 1602, which multiplexes data streams across the antennas 1612 according to known or assumed channel characteristics, such that each data stream is received at an appropriate signal strength relative to other streams and at a desired location in space (e.g., the location of the receiver associated with that data stream). Certain embodiments can use a single-user MIMO (SU-MIMO) approach (where data streams are all directed to a single receiver) and / or a multi-user MIMO (MU-MIMO) approach (where individual data streams can be directed to individual (different) receivers at different locations in space).

[0204] In some implementations with multiple antennas, the wireless device 1602 can implement analog beamforming techniques, whereby the phase of the signal transmitted by the antenna 1612 is relatively adjusted to enable the (joint) transmission of the directional antenna 1612 (this is sometimes referred to as beam control).

[0205] Wireless device 1602 may include one or more interfaces 1614. Interface 1614 can be used to provide input to or output to wireless device 1602. For example, wireless device 1602 as a UE may include interface 1614, such as a microphone, speaker, touchscreen, button, etc., to allow users of the UE to input to and / or output to the UE. Other interfaces of such UEs may consist of transmitters, receivers, and other circuitry (e.g., in addition to the transceiver 1610 / antenna 1612 already described), allowing the UE to communicate with other devices and according to known protocols (e.g., (etc.) to perform the operation.

[0206] Wireless device 1602 may include a frequency-selective precoding module 1616. The frequency-selective precoding module 1616 may be implemented via hardware, software, or a combination thereof. For example, the frequency-selective precoding module 1616 may be implemented as a processor, circuitry, and / or instructions 1608 stored in memory 1606 and executed by processor 1604. In some examples, the frequency-selective precoding module 1616 may be integrated within processor 1604 and / or transceiver 1610. For example, the frequency-selective precoding module 1616 may be implemented via a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within processor 1604 or transceiver 1610.

[0207] The frequency-selective precoding module 1616 can be used in various aspects of this disclosure, for example, Figures 1 to 14 All aspects. The frequency selective precoding module 1616 can configure the wireless device 1602 to receive TRI, wideband TPMI and / or subband TPMI from the base station; receive RRC configuration information, MAC CE information and / or DCI indicating whether PUSCH transmission will be performed using a precoder corresponding to the wideband TPMI or a precoder corresponding to the subband TPMI; and / or transmit PUSCH transmission in the manner discussed herein (among other possible behaviors) according to the precoder corresponding to the indicated subband TPMI or wideband TPMI (as the case may be).

[0208] The network device 1618 can include one or more processors 1620. The processors 1620 can execute instructions to perform various operations of the network device 1618, as described herein. The processors 1620 can include one or more baseband processors implemented with, for example, CPUs, DSPs, ASICs, controllers, FPGA devices, another hardware devices, firmware devices, or any combination thereof to perform the operations described herein.

[0209] The network device 1618 can include memory 1622. The memory 1622 can be a non-transitory computer-readable storage medium that stores instructions 1624 (which can include, for example, computer program instructions executable by the processors 1620). The instructions 1624 can also be referred to as program code or computer programs. The memory 1622 can also store data used by the processors 1620 and results of operations performed by the processors 1620.

[0210] The network device 1618 can include one or more transceivers 1626, which can include RF transmitter and / or receiver circuits that use the antennas 1628 of the network device 1618 to facilitate transmission or reception of signaling (e.g., signaling 1634) by the network device 1618 with other devices (e.g., the wireless devices 1602) in accordance with a corresponding RAT.

[0211] The network device 1618 can include one or more antennas 1628 (e.g., one, two, four, or more). In embodiments with multiple antennas 1628, the network device 1618 can perform MIMO, digital beamforming, analog beamforming, beam steering, etc., as described herein.

[0212] The network device 1618 can include one or more interfaces 1630. The interfaces 1630 can be used to provide input to or output from the network device 1618. For example, the network device 1618 as a base station can include interfaces 1630 consisting of transmitters, receivers, and other circuitry (e.g., in addition to the transceivers 1626 / antennas 1628 already described) that enable the base station to communicate with other equipment in a core network and / or to communicate with external networks, computers, databases, etc. to perform operations, management, and maintenance of the base station or other equipment with which the base station is operatively connected.

[0213] The network device 1618 can include a frequency-selective precoding module 1632. The frequency-selective precoding module 1632 can be implemented via hardware, software, or combinations thereof. For example, the frequency-selective precoding module 1632 can be implemented as a processor, circuit, and / or instructions 1624 stored in the memory 1622 and executed by the processor 1620. In some examples, the frequency-selective precoding module 1632 can be integrated within the processor 1620 and / or the transceiver 1626. For example, the frequency-selective precoding module 1632 can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the processor 1620 or the transceiver 1626.

[0214] The frequency-selective precoding module 1632 can be used for various aspects of the present disclosure, for example, Figures 1 to 14 Aspects of the frequency-selective precoding module 1632. For example, the frequency-selective precoding module 1632 can configure the network device 1618 to indicate a TRI, a wideband TPMI, and / or a subband TPMI to a UE, and / or to transmit RRC configuration information, MAC CE information, and / or DCI to indicate whether to use a precoder corresponding to the wideband TPMI or a precoder corresponding to the subband TPMI for a PUSCH transmission (among other possible behaviors).

[0215] For one or more embodiments, at least one of the components shown in one or more of the preceding figures can be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, a baseband processor as described herein in connection with one or more of the preceding figures can be configured to operate in accordance with one or more of the examples described herein. As another example, circuitry associated with a UE, base station, network element, etc. as described above in connection with one or more of the preceding figures can be configured to operate in accordance with one or more of the examples shown herein.

[0216] Any of the above-described embodiments can be combined in any combination with any other embodiment (or combination of embodiments), unless specifically noted otherwise. The foregoing description of one or more implementations provides functionality and / or technical advantages, but do not limit the implementations to the precise form described. Modifications and variations are possible in light of the above teachings or can be acquired from practice of the implementations. For example, other implementations can have more, other, or fewer steps than those disclosed.

[0217] Embodiments and implementations of the systems and methods described herein can include various operations, which can be reflected in machine-executable instructions to be executed by a computer system. The computer system can include one or more general- or special-purpose computers (or other electronic devices). The computer system can include hardware components that include specific logic for performing the operations, or can include a combination of hardware, software, and / or firmware.

[0218] It should be recognized that the systems described herein include descriptions of specific embodiments. These embodiments can be combined into a single system, incorporated into other systems, divided into multiple systems, or otherwise divided or combined. Further, it is contemplated that parameters, attributes, aspects, etc. of one embodiment can be used in another embodiment. For clarity, these parameters, attributes, aspects, etc. are only described in one or more embodiments, and it should be recognized that these parameters, attributes, aspects, etc. can be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment unless specifically stated otherwise herein.

[0219] It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled in a way that minimizes risks to the privacy of the users and is used only for authorized purposes.

[0220] Although the foregoing has been described in some detail for purposes of clarity, it will be apparent that certain changes and modifications can be made without departing from the principles thereof. It should be noted that there are many alternative ways of implementing both the processes and apparatuses described herein. Accordingly, the embodiments of the application are to be considered illustrative and not restrictive, and the description is not to be limited to the details given herein, but can be modified within the scope and equivalents of the appended claims.

Claims

1. A method for a user equipment (UE), comprising: Decode the first level of the two-level downlink control information (DCI) transmitted on the scheduling physical uplink shared channel (PUSCH) received from the base station; Based on the first-level DCI, a plurality of precoding matrices are determined to be used to precode the transmission using a plurality of subband transmission precoder matrix indicators (TPMIs) of the second-level DCI of the two-level DCI, wherein the determination of the plurality of precoding matrices indicated by the plurality of subband TPMIs based on the first-level DCI is based on the determination of the starting control channel element (CCE) index of the physical downlink control channel (PDCCH) carrying the first-level DCI. Decode the second-level DCI with the multiple sub-band TPMIs of the two-level DCI; The transmission is precoded using the plurality of precoding matrices indicated by the plurality of subband TPMIs; as well as The transmission is sent on the PUSCH.

2. The method of claim 1, wherein the determination of the starting CCE index means that the starting CCE index is odd.

3. The method of claim 1, wherein the first-level DCI is transmitted in a first search space SS and the second-level DCI is transmitted in a second SS.

4. The method according to claim 1, wherein the first-level DCI is transmitted in the primary control channel element set PCCE of the search space SS and the second-level DCI is transmitted in the secondary control channel element set SCCE of the SS.

5. The method of claim 1, wherein the UE is capable of performing coherent transmission, and wherein the plurality of precoding matrices indicated by the plurality of subband TPMIs include coherent interferometric coding matrices.

6. The method of claim 1, wherein the UE is capable of performing partially coherent transmission, and wherein the plurality of precoding matrices indicated by the plurality of subband TPMIs include partially coherent coding matrices.

7. The method of claim 1, wherein the first-level DCI comprises a broadband TPMI.

8. The method of claim 1, wherein the transmission is transmitted on a plurality of subbands corresponding to the plurality of subbands TPMI.

9. A method for a base station, comprising: Sending a first-level DCI of a two-level downlink control information (DCI) to a user equipment (UE) to schedule transmissions on the Physical Uplink Shared Channel (PUSCH), wherein the first-level DCI is configured to indicate, by being sent in the Physical Downlink Control Channel (PDCCH) with a Start Control Channel Element (CCE) index, that multiple precoding matrices indicated by multiple subband transmission precoder matrix indicators (TPMIs) of the second-level DCI of the two-level DCI will be used to precode the transmissions, the start CCE index corresponding to the use of the multiple subband TPMIs. Send the second-level DCI with the plurality of sub-band TPMIs to the UE; as well as The UE receives the transmission on the PUSCH that has been precoded using the multiple precoding matrices indicated by the multiple subband TPMIs.

10. The method of claim 9, wherein the starting CCE index corresponds to the use of the plurality of subband TPMIs, because the starting CCE index is odd.

11. The method of claim 9, wherein the first-level DCI is transmitted in a first search space SS and the second-level DCI is transmitted in a second SS.

12. The method of claim 9, wherein the first-level DCI is transmitted in the primary control channel element set PCCE of the search space SS and the second-level DCI is transmitted in the secondary control channel element set SCCE of the SS.

13. The method of claim 9, wherein the UE is capable of performing coherent transmission, and wherein the plurality of precoding matrices indicated by the plurality of subband TPMIs include coherent interferometric coding matrices.

14. The method of claim 9, wherein the UE is capable of performing partially coherent transmission, and wherein the plurality of precoding matrices indicated by the plurality of subband TPMIs include partially coherent coding matrices.

15. The method of claim 9, wherein the first-level DCI comprises a broadband TPMI.

16. The method of claim 9, wherein the transmission is received on a plurality of subbands corresponding to the plurality of subbands TPMI.

17. An apparatus for wireless communication, the apparatus comprising components for performing the method according to any one of claims 1 to 16.

18. A computer-readable medium storing instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform the method according to any one of claims 1 to 16.

19. An apparatus for wireless communication, the apparatus comprising a logic component, module, or circuit for performing the method according to any one of claims 1 to 16.

Images