Patent Description:
Wireless communication systems are widely known in which base stations (also known as eNBs or gNBs, depending on the network type) communicate with mobile devices (also known as user equipments (UEs)) which are within range of the base stations. Each base station divides its available bandwidth, such as frequency and time resources, into different resource allocations for different UEs. For example, UE can be configured with one or more sounding reference signal (SRS) resources for uplink (UL) transmission.

MIMO is one technique used for data transmission in wireless communication systems. A MIMO communication system can employ multiple antennas at the transmitter and/or at the receiver (often at both) to enhance the data capacity achievable between the transmitter and the receiver. Every transmit (TX) antenna in a MIMO system is usually provided with at least one RF or TX chain, which may have separate or shared transmitters or TX components. However, there will be different coherent transmission capabilities among different TX chains. This leads to different UL coherent transmission capabilities, such as full/non/partial-coherent transmission between SRS ports of one or more SRS resources.

The document discusses a procedure of codebook based UL transmission.

<CIT>discusses a transceiver set selection and communication scheme for a distributed antenna system.

Thus, there is a need for providing coherent transmission capabilities of the TX chains of the UEs to the base station to facilitate the configuration of the codebook or coherent transmission for the UEs.

According to an embodiment of the present disclosure, a method comprises: transmitting the number of antenna panels equipped at a user equipment (UE), the number of antenna panels being at least one; transmitting the number of panel groups (PGs), wherein each PG includes one antenna panel or more than one antenna panels sharing at least one transmit (TX) component of the UE; transmitting PG information indicating which antenna panel is grouped into which PG; transmitting the number of coherent PGs (CPGs), wherein each CPG includes at least two PGs and the antenna panels in the at least two PGs of each CPG are coherent; and transmitting CPG information indicating which PG is grouped into which CPG.

According to another embodiment of the present disclosure, a method comprises: receiving the number of antenna panels equipped at a user equipment (UE), the number of antenna panels being at least one; receiving the number of panel groups (PGs), wherein each PG includes one antenna panel or more than one antenna panels sharing at least one transmit (TX) component of the UE; receiving PG information indicating which antenna panel is grouped into which PG; receiving the number of coherent PGs (CPGs), wherein each CPG includes at least two PGs and the antenna panels in the at least two PGs of each CPG are coherent; and receiving CPG information indicating which PG is grouped into which CPG.

Embodiments of the present disclosure also provide apparatuses for performing the above methods.

In an embodiment of the present disclosure, an apparatus comprises one or more transmitters, and one or more antenna panels, wherein each antenna panel corresponds to at least one transmit (TX) component of the one or more transmitters. The one or more transmitters: transmit the number of the one or more antenna panels; transmit the number of panel groups (PGs), wherein each PG includes one antenna panel or more than one antenna panels sharing at least one TX component; transmit PG information indicating which antenna panel is grouped into which PG; transmit the number of coherent PGs (CPGs), wherein each CPG includes at least two PGs and the antenna panels in the at least two PGs of each CPG are coherent; and transmit CPG information indicating which PG is grouped into which CPG.

Embodiments of the present disclosure also provide non-transitory computer-readable media having stored thereon computer-executable instructions to cause a processor to implement the above methods.

In order to describe the manner in which advantages and features of the disclosure can be obtained, a description of the disclosure is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only example embodiments of the disclosure and are not therefore to be considered to be limiting of its scope.

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present disclosure, and is not intended to represent the only form in which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the scope of the present disclosure.

<FIG> illustrates a wireless communication system <NUM> according to an embodiment of the disclosure.

As shown in <FIG>, the wireless communication system <NUM> includes a plurality of base stations <NUM> including base stations 10a and 10b, and a plurality of UEs <NUM> including UEs 12a, 12b and 12c. The plurality of base stations <NUM> may be based on the standards of long-term evolution (LTE), LTE-Advanced (LTE-A), new radio (NR), or other suitable standards. For example, the plurality of base stations <NUM> may be a plurality of eNBs, or a plurality of gNBs. In an embodiment of the disclosure, the plurality of base stations <NUM> may be controlled by a control unit (not shown). Each base station <NUM> may define one or more cells <NUM>, such as cell 16a or 16b, and each cell <NUM> may support mobility management through the radio resource control (RRC) signaling. A group of cells <NUM> may form a radio access network-based (RAN-based) notification area (RNA). The UE <NUM> may be a computing device, a wearable device, and a mobile device, etc. The UEs with reference numerals 12a, 12b and 12c may represent the same UE moving in different locations within the coverage of the cell 16a or 16b, or different UEs. Persons skilled in the art should understand that as the 3GPP and the communication technology develop, the terminologies recited in the specification may change, which should not affect the principle of the disclosure.

<FIG> shows a MIMO communication system <NUM> including a receiver <NUM> and a transmitter <NUM> according to an embodiment of the disclosure. For downlink (DL) transmission, receiver <NUM> may be part of a UE, and transmitter <NUM> may be part of a base station. For uplink (UL) transmission, receiver <NUM> may be part of a base station, and transmitter <NUM> may be part of a UE. In an embodiment, a UE or a base station may include one or more receivers and one or more transmitters as shown in <FIG>.

In <FIG>, the transmitter <NUM> includes multiple TX antennas or antenna panels (i.e., antennas 213a, 213b,. and 213t), and the receiver <NUM> includes multiple receive (RX) antennas or antenna panels (i.e., antennas 211a, 211b,. The TX/RX antenna panel may have separate or shared TX/RX components, such as Digital-to-Analog Converter (DAC) and Phase-Locked Loop (PLL). When TX/RX antenna panels have shared TX/RX components, only one panel in these TX/RX panels can transmit/receive at a time (by means of panel switching or panel selection). When TX/RX antenna panels have separate TX/RX components, these TX/RX panels can transmit/receive independently. Moreover, coherent transmission can be supported if the antenna panels are all coherent or calibrated. However, only non-coherent or partial-coherent transmission can be applied when those antenna panels are not coherent or calibrated.

In an embodiment, the transmitter <NUM> may utilize TX beamforming technique. Possible TX beamforming schemes include analog, digital, and hybrid TX beamforming. Different TX beamforming schemes have different capabilities. For example, for analog beamforming, only one TX chain is equipped for one panel, and thus only one SRS port can be configured for one SRS resource of a corresponding panel. For digital or hybrid beamforming, multiple TX chains are equipped for one panel, and thus multiple SRS ports can be configured for one SRS resource of a corresponding panel. There will be different coherent transmission capabilities among different TX chains. In particular, for digital or hybrid beamforming, different SRS ports may have different coherent levels. Also, there will be different coherent transmission capabilities between different antenna panels. This leads to different coherent transmission capabilities, such as full/non/partial-coherent transmission between different SRS ports of one or more SRS resources. Therefore, there is a need for providing coherent transmission capabilities of the TX chains to the base station to facilitate the configuration of the codebook or coherent transmission for the UE. In the following, proposed schemes are presented in details.

<FIG> illustrates a flow chart for a method <NUM> for transmitting coherent information according to an embodiment of the disclosure.

As shown in <FIG>, in step <NUM>, the number of antenna panels equipped at a UE is transmitted. In an embodiment, the number of the antenna panels is at least one. In step <NUM>, the number of panel groups (PGs) is transmitted. In an embodiment, each PG includes one antenna panel or more than one antenna panels sharing at least one TX component of the UE. In step <NUM>, PG information indicating which antenna panel is grouped into which PG is transmitted. In step <NUM>, the number of coherent PGs (CPGs) is transmitted. In an embodiment, each CPG includes at least two PGs, and the antenna panels in the at least two PGs of each CPG are coherent or calibrated. In step <NUM>, CPG information indicating which PG is grouped into which CPG is transmitted. In an embodiment, the above information regarding the UE capability maybe signaled to a base station (e.g., gNB) through RRC messages.

In an embodiment, the method <NUM> may further transmit an indicator of beamforming architecture of the UE. For example, the indicator may indicate that the UE employs an analog beamforming architecture. In another example, the indicator may indicate that the UE employs a hybrid or digital beamforming architecture. In the latter case, the method <NUM> may further transmit the number of SRS ports. When the UE employs a hybrid or digital beamforming architecture, each antenna panel may support a plurality SRS ports. The method <NUM> then further transmits, for each antenna panel, the number of coherent SRS port groups (CSPGs). In an embodiment, each CSPG includes at least two SRS ports that are coherent. The method <NUM> also transmits, for each CSPG, CSPG information indicating which SRS port is grouped into which CSPG.

In an example, assuming that a UE employs an analog beamforming architecture, the US may then signal the following coherent information to a base station (e.g., gNB):
{
Indicator for beamforming architecture: analog beamforming;
Number of panels;
Number of PGs;
Panels in each PG;
Number of CPG;
Panel groups in each CPG;
}.

As mentioned above, in analog beamforming, each panel only has one TX chain, and a UE may be equipped with multiple panels. The transmission of the above information thus allows the UE to support high rank and coherent transmission. For example, "Panels in each PG" indicates the panels that share TX components (such as DAC and PLL). That is, panels sharing any TX component are defined as a PG, where two panels in a same PG cannot transmit together, and different panels in different PGs can transmit together. If all panels have separated TX chains, each panel will belong to a single PG. Moreover, "Panel groups in each CPG" indicates the panels/PGs that are calibrated and can transmit coherently. Panels in different CPGs are not calibrated and cannot transmit coherently.

In an embodiment, assuming that <NUM> panels are equipped at the UE side with analog beamforming, wherein panel <NUM> (P<NUM>) and panel <NUM> (P<NUM>) share one TX chain, panel <NUM> (P<NUM>) and panel <NUM> (P<NUM>) share another TX chain, and these two TX chains are calibrated or coherent, the above coherent information from the UE to the gNB may be implemented as follows:
<IMG>
<IMG>.

In another embodiment, assuming that all <NUM> panels in the above embodiment have separated TX chains, wherein TX chains of panel <NUM> and panel <NUM> are coherent, TX chains of panel <NUM> and panel <NUM> are coherent, TX chains of panel <NUM>/<NUM> and TX chains of panel <NUM>/<NUM> are not coherent, the above coherent information from the UE to the gNB may be implemented as follows:
<IMG>.

In another example, assuming that a UE employs a hybrid and digital beamforming architecture, the US may then signal the following coherent information to a base station (e.g., gNB):
{
Indicator for beamforming architecture: hybrid/digital beamforming;
Number of panels;
Number of SRS ports;
Number of CSPG for each panel;
SRS ports in each CSPG;
Number of panel groups;
Panels in each panel groups;
Number of CPG;
Panel groups in each CPG;
}.

As mentioned above, in hybrid and digital beamforming, each panel may have multiple TX chains, which correspond to multiple SRS ports. Since different TX chains or different SRS ports may have different coherent levels, the UE may signal one or more CSPGs, wherein all SRS ports in a same CSPG are calibrated and can transmit coherently, while any two SRS ports in different CSPGs are not calibrated and cannot transmit coherently. Similar to analog beamforming architecture, the UE should also signal the information regarding the PGs and CPGs.

In an embodiment, assuming that <NUM> panels are equipped at the UE side, and each panel has <NUM> TX chains corresponding to <NUM> SRS ports, the coherent information from the UE to the gNB may be implemented as follows:
<IMG>.

In another embodiment, still assuming that <NUM> panels are equipped at the UE side, and each panel has <NUM> TX chains corresponding to <NUM> SRS ports, the coherent information from the UE to the gNB may be implemented as follows:
<IMG>.

In this case, the above information indicates:.

In an embodiment, the method <NUM> may further comprise grouping antenna panels sharing at least one TX component of the UE into corresponding PGs.

In another embodiment, the method <NUM> may further comprise grouping coherent PGs into corresponding CPGs.

In yet another embodiment, the method <NUM> may further comprise grouping coherent SRS ports into corresponding CSPGs.

In still another embodiment, the method <NUM> may further comprise in response to receiving a transmitted precoding matrix indicator (TPMI), transmitting Physical Uplink Shared Channel (PUSCH) with precoders corresponding to the TPMI.

<FIG> illustrates a flow chart for a method <NUM> for receiving coherent information according to an embodiment of the disclosure.

As shown in <FIG>, in step <NUM>, the number of antenna panels equipped at a UE is received. In an embodiment, the number of the antenna panels is at least one. In step <NUM>, the number of PGs is received. In an embodiment, each PG includes one antenna panel or more than one antenna panels sharing at least one TX component of the UE. In step <NUM>, PG information indicating which antenna panel is grouped into which PG is received. In step <NUM>, the number of CPGs is received. In an embodiment, each CPG includes at least two PGs, and the antenna panels in the at least two PGs of each CPG are coherent. In step <NUM>, CPG information indicating which PG is grouped into which CPG is received.

In an embodiment, the method <NUM> may further comprise receiving an indicator of beamforming architecture of the UE. For example, the indicator may indicate that the UE employs an analog beamforming architecture. In another example, the indicator may indicate that the UE employs a hybrid or digital beamforming architecture. In the latter case, the method <NUM> may further comprise receiving the number of SRS ports. As mentioned above, when the UE employs a hybrid or digital beamforming architecture, each antenna panel may support a plurality SRS ports. The method <NUM> then further receives, for each antenna panel, the number of CSPGs. In an embodiment, each CSPG includes at least two SRS ports that are coherent. The method <NUM> also receives, for each CSPG, CSPG information indicating which SRS port is grouped into which CSPG.

The above coherent transmission capability information may be received by a base station (e.g., gNB) through RRC messages. In response to receiving the above information, the base station may allocate SRS resources based on the received coherent transmission capability information. For example, the base station may determine the UL SRS beam (UL TX beam/precoder) used for PUSCH and indicate the selected SRS beam to UE through an SRS resource indicator (SRI). SRI is a key component of both codebook-based and non-codebook-based UL MIMO. For codebook based UL MIMO, an additional TX precoder may be applied on top of the selected SRS beams.

In an embodiment, the method <NUM> further comprises in response to receiving the PG information, determining an SRI for UE UL transmission in a transmission time interval (TTI) based at least on selecting no more than one antenna panel from a PG at a time. In another embodiment, the method <NUM> further comprises transmitting the SRI to the UE.

In an embodiment, the method <NUM> further comprises in response to receiving the CPG information, determining a TPMI for UE UL transmission in a TTI based at least on not configuring coherent transmission between antenna panels in different CPGs. In another embodiment, the method <NUM> further comprises in response to receiving the CSPG information, determining the TPMI for UE UL transmission in a TTI based at least on not configuring coherent transmission between SRS ports in different CSPGs. In yet another embodiment, the method <NUM> further comprises transmitting the TPMI to the UE.

<FIG> illustrates a block diagram of an apparatus <NUM> for transmitting coherent information according to an embodiment of the disclosure. The apparatus <NUM> may perform method <NUM> as described above. The apparatus <NUM> may be a UE such as a computing device, a wearable device, and a mobile device. The apparatus <NUM> can communicate with a base station.

As shown in <FIG>, the apparatus <NUM> may include a memory <NUM>, a processor <NUM>, a transmitter <NUM>, and a plurality of antennas or antenna panels including antennas/antenna panels 504a, 504b,. The transmitter <NUM> may comprise TX components such as DAC and/or PLL (not shown). Although in this figure, elements such as memory, processor, and transmitter are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

In an embodiment, the apparatus <NUM> may comprise one or more transmitters and one or more antenna panels, wherein each antenna panel corresponds to at least one TX component of the one or more transmitters. The one or more transmitters may transmit the number of the one or more antenna panels; transmit the number of PGs, wherein each PG includes one antenna panel or more than one antenna panels sharing at least one TX component; transmit PG information indicating which antenna panel is grouped into which PG; transmit the number of CPGs, wherein each CPG includes at least two PGs and the antenna panels in the at least two PGs of each CPG are coherent; and transmit CPG information indicating which PG is grouped into which CPG.

In another embodiment, the one or more transmitters may further transmit an indicator of beamforming architecture of the apparatus. For example, the indicator may indicate that the apparatus employs an analog beamforming architecture. In another example, the indicator may indicate that the apparatus employs a hybrid or digital beamforming architecture. In the latter case, each antenna panel may support a plurality of SRS ports. The one or more transmitters may further transmit the number of SRS ports supported by the one or more antenna panels. The one or more transmitters then further transmit, for each antenna panel, the number of CSPGs. In an embodiment, each CSPG includes at least two SRS ports that are coherent. The one or more transmitters also transmit, for each CSPG, CSPG information indicating which SRS port is grouped into which CSPG.

In yet another embodiment, the processor <NUM> is coupled to one or more transmitters, and groups antenna panels sharing at least one TX component of the apparatus into corresponding PGs.

In still another embodiment, the processor <NUM> is coupled to one or more transmitters, and groups coherent PGs into corresponding CPGs.

In yet still another embodiment, the processor <NUM> is coupled to one or more transmitters, and groups coherent SRS ports into corresponding CSPGs.

In still yet another embodiment, the one or more transmitters further transmit, in response to receiving a TPMI, PUSCH with precoders corresponding to the TPMI.

<FIG> illustrates a block diagram of an apparatus <NUM> for receiving coherent information according to an embodiment of the disclosure. The apparatus <NUM> may perform method <NUM> as described above. The apparatus <NUM> may be a base station that can communicate with UE(s).

As shown in <FIG>, the apparatus <NUM> may include a memory <NUM>, a processor <NUM>, a transmitter <NUM>, and a receiver <NUM>. Although in this figure, elements such as memory, processor, transmitter, and receiver are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In an embodiment, the processor <NUM> may perform method <NUM> as described above.

Those having ordinary skill in the art would understand that the steps of a method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the steps of a method may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

Claim 1:
A method (<NUM>) performed by a user equipment, UE (<NUM>), the method comprising:
transmitting (<NUM>) the number of antenna panels (<NUM>) equipped at the user equipment (<NUM>), the number of antenna panels (<NUM>) being at least two;
transmitting (<NUM>) the number of panel groups, wherein each panel group includes one antenna panel (<NUM>) or more than one antenna panel (<NUM>) sharing at least one transmit component of the UE (<NUM>);
transmitting (<NUM>) panel group information indicating which antenna panel (<NUM>) is grouped into which panel group;
transmitting (<NUM>) the number of coherent panel groups, wherein each coherent panel group includes at least two panel groups and the antenna panels (<NUM>) in the at least two panel groups of each coherent panel group are coherent;
transmitting (<NUM>) coherent panel group information indicating which panel group is grouped into which coherent panel group; and
transmitting an indicator of beamforming architecture of the UE (<NUM>), wherein the indicator indicates that the UE employs a digital beamforming architecture or a hybrid beamforming architecture, and
the method further comprises:
transmitting the number of sounding reference signal ports, wherein each antenna panel (<NUM>) supports a plurality sounding reference signal ports;
transmitting, for each antenna panel (<NUM>), the number of coherent sounding reference signal port groups, CSPGs, wherein each CSPG includes at least two sounding reference signal ports that are coherent; and
transmitting, for each CSPG, CSPG information indicating which sounding reference signal port is grouped into which CSPG.