Patent Description:
The invention is defined in independent claims <NUM>, <NUM> and <NUM>.

SONY: "Remaining issues in Pre-emption Indicator",.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for physical downlink shared channel (PDSCH) processing in presence of downlink preemption indication (DLPI).

In certain systems, such as NR (new radio or <NUM>) systems, a scheduled physical downlink shared channel (PDSCH) transmission may be preempted by another PDSCH transmission. For example, NR supports a variety of services including enhanced mobile broadband (eMBB) service and ultra-reliable low-latency communications (URLLC) service. An eMBB PDSCH transmission to a user equipment (UE) may be preempted by a URLLC PDSCH transmission to the UE or another UE. A base station (BS) provides a downlink preemption indicator (DLPI) to the UE, indicating the preempted resources, to improve decoding performance at the UE, for example.

When the BS schedules a PDSCH transmission, the BS sends a feedback timing indicator indicating when the UE should provide feedback, such as hybrid automatic repeat request (HARQ) feedback, for the scheduled PDSCH transmission. If the UE waits, after receiving the scheduled PDSCH, to account for the DLPI in processing the received PDSCH, then the UE may have insufficient time to complete the processing before the indicated feedback timing. Therefore, techniques for PDSCH processing in the presence of the DLPI are desirable.

For example, the wireless communication network <NUM> may be a New Radio (NR) or <NUM> network. The wireless communication network <NUM> may support enhanced mobile broadband (eMBB) and ultra-reliable low-latency communication (URLLC) services. A base station (BS), such as a BS 110a in the wireless communication network <NUM> may schedule physical downlink shared channel (PDSCH) transmission to a user equipment (UE), such as a UE 120a in the wireless communication network <NUM>. The BS <NUM> may preempt the scheduled PDSCH with another PDSCH. For example, the BS 110a may schedule an eMBB PDSCH transmission to the UE 120a in a slot, then the BS 110a may transmit a URLLC PDSCH, to the UE 120a or to another UE <NUM> in one more symbols of the slot scheduled for the eMBB PDSCH, the URLCC PDSCH preempting the eMBB PDSCH. The BS 110a may send the UE 120a a downlink preemption indictor (DLPI) indicating the preempted resources. The BS 110a may ensure that the UE 120a can process the PDSCH taking into account the preempted resources. For example, the BS 110a determines a feedback timing indicator associated with the scheduled PDSCH. As shown in <FIG>, the BS 110a has a module for determining a sufficient k1 value. The BS 110a may determine the feedback timing indicator based on the number of slots between the scheduled PDSCH and the DLPI and on the minimum processing time associated with the UE. The BS 110a includes the feedback timing indicator in the downlink control information (DCI) scheduling the PDSCH. The UE 120a can determine how to process the PDSCH based on the feedback timing indicator. For example, as shown in <FIG>, the UE 120a has a module for determining how to process PDSCH based on a k1 value, according to aspects described herein.

As illustrated in <FIG>, the wireless communication network <NUM> may include a number of base stations (BSs) <NUM> and other network entities. A BS may be a station that communicates with user equipments (UEs). Each BS <NUM> may provide communication coverage for a particular geographic area. In NR systems, the term "cell" and next generation NodeB (gNB or gNodeB), NR BS, <NUM> NB, access point (AP), or transmission reception point (TRP) may be interchangeable. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network <NUM> through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

Some UEs may be considered Intemet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

<FIG> illustrates an example architecture of a distributed Radio Access Network (RAN) <NUM>, which may be implemented in the wireless communication network <NUM> illustrated in <FIG>. <FIG>, the distributed RAN includes Core Network (CN) <NUM> and Access Node <NUM>.

The CN <NUM> may host core network functions. CN <NUM> may be centrally deployed. CN <NUM> functionality may be offloaded (e.g., to advanced wireless services (AWS)), in an effort to handle peak capacity. The CN <NUM> may include the Access and Mobility Management Function (AMF) <NUM> and User Plane Function (UPF) <NUM>. The AMF <NUM> and UPF <NUM> may perform one or more of the core network functions.

The AN <NUM> may communicate with the CN <NUM> (e.g., via a backhaul interface). The AN <NUM> may communicate with the AMF <NUM> via an N2 (e.g., NG-C) interface. The AN <NUM> may communicate with the UPF <NUM> via an N3 (e.g., NG-U) interface. The AN <NUM> may include a central unit-control plane (CU-CP) <NUM>, one or more central unit-user plane (CU-UPs) <NUM>, one or more distributed units (DUs) <NUM>-<NUM>, and one or more Antenna/Remote Radio Units (AU/RRUs) <NUM>-<NUM>. The CUs and DUs may also be referred to as gNB-CU and gNB-DU, respectively. One or more components of the AN <NUM> may be implemented in a gNB <NUM>. The AN <NUM> may communicate with one or more neighboring gNBs.

The CU-CP <NUM> may be connected to one or more of the DUs <NUM>-<NUM>. The CU-CP <NUM> and DUs <NUM>-<NUM> may be connected via a F1-C interface2, the CU-CP <NUM> may be connected to multiple DUs, but the DUs may be connected to only one CU-CP. Although <FIG> only illustrates one CU-UP <NUM>, the AN <NUM> may include multiple CU-UPs. The CU-CP <NUM> selects the appropriate CU-UP(s) for requested services (e.g., for a UE). The CU-UP(s) <NUM> may be connected to the CU-CP <NUM>. For example, the DU-UP(s) <NUM> and the CU-CP <NUM> may be connected via an E1 interface. The CU-CP(s) <NUM> may be connected to one or more of the DUs <NUM>-<NUM>. The CU-UP(s) <NUM> and DUs <NUM>-<NUM> may be connected via a F1-U interface2, the CU-CP <NUM> may be connected to multiple CU-UPs, but the CU-UPs may be connected to only one CU-CP.

A DU, such as DUs <NUM>, <NUM>, and/or <NUM>, may host one or more TRP(s) (transmit/receive points, which may include an Edge Node (EN), an Edge Unit (EU), a Radio Head (RH), a Smart Radio Head (SRH), or the like). A DU may be located at edges of the network with radio frequency (RF) functionality. A DU may be connected to multiple CU-UPs that are connected to (e.g., under the control of) the same CU-CP (e.g., for RAN sharing, radio as a service (RaaS), and service specific deployments). DUs may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE. Each DU <NUM>-<NUM> may be connected with one of AU/RRUs <NUM>-<NUM>.

The CU-CP <NUM> may be connected to multiple DU(s) that are connected to (e.g., under control of) the same CU-UP <NUM>. Connectivity between a CU-UP <NUM> and a DU may be established by the CU-CP <NUM>. For example, the connectivity between the CU-UP <NUM> and a DU may be established using Bearer Context Management functions. Data forwarding between CU-UP(s) <NUM> may be via a Xn-U interface.

The distributed RAN <NUM> may support fronthauling solutions across different deployment types. For example, the RAN <NUM> architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter). The distributed RAN <NUM> may share features and/or components with LTE. For example, AN <NUM> may support dual connectivity with NR and may share a common fronthaul for LTE and NR. The distributed RAN <NUM> may enable cooperation between and among DUs <NUM>-<NUM>, for example, via the CU-CP <NUM>. An inter-DU interface may not be used.

Logical functions may be dynamically distributed in the distributed RAN <NUM>. As will be described in more detail with reference to <FIG>, the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, Physical (PHY) layers, and/or Radio Frequency (RF) layers may be adaptably placed, in the AN and/or UE.

<FIG> illustrates a diagram showing examples for implementing a communications protocol stack <NUM> in a RAN (e.g., such as the RAN <NUM>), according to aspects of the present disclosure. The illustrated communications protocol stack <NUM> may be implemented by devices operating in a wireless communication system, such as a <NUM> NR system (e.g., the wireless communication network <NUM>). In various examples, the layers of the protocol stack <NUM> may be implemented as separate modules of software, portions of a processor or ASIC, portions of non-collocated devices connected by a communications link, or various combinations thereof. Collocated and non-collocated implementations may be used, for example, in a protocol stack for a network access device or a UE3, the system may support various services over one or more protocols. One or more protocol layers of the protocol stack <NUM> may be implemented by the AN and/or the UE.

As shown in <FIG>, the protocol stack <NUM> is split in the AN (e.g., AN <NUM> in <FIG>). The RRC layer <NUM>, PDCP layer <NUM>, RLC layer <NUM>, MAC layer <NUM>, PHY layer <NUM>, and RF layer <NUM> may be implemented by the AN. For example, the CU-CP (e.g., CU-CP <NUM> in <FIG>) and the CU-UP e.g., CU-UP <NUM> in <FIG>) each may implement the RRC layer <NUM> and the PDCP layer <NUM>. A DU (e.g., DUs <NUM>-<NUM> in <NUM>) may implement the RLC layer <NUM> and MAC layer <NUM>. The AU/RRU (e.g., AU/RRUs <NUM>-<NUM> in <FIG>) may implement the PHY layer(s) <NUM> and the RF layer(s) <NUM>. The PHY layers <NUM> may include a high PHY layer and a low PHY layer.

The UE may implement the entire protocol stack <NUM> (e.g., the RRC layer <NUM>, the PDCP layer <NUM>, the RLC layer <NUM>, the MAC layer <NUM>, the PHY layer(s) <NUM>, and the RF layer(s) <NUM>).

<FIG> illustrates example components of BS <NUM> and UE <NUM> (as depicted in <FIG>), which may be used to implement aspects of the present disclosure. For example, antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE <NUM> and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS <NUM> may be used to perform the various techniques and methods described herein. For example, as shown in <FIG>, the processor <NUM> has a module for determining a sufficient k1 value, according to aspects described herein. As another example, as shown in <FIG>, the processor <NUM> has a module for determining how to process PDSCH based on a k1 value, according to aspects described herein.

The controllers/processors <NUM> and <NUM> may direct the operation at the BS <NUM> and the UE <NUM>, respectively.

<FIG> illustrates an example system architecture <NUM> for interworking between 5GS (e.g., such as the distributed RAN <NUM>) and E-UTRAN-EPC, in accordance with certain aspects of the present disclosure. As shown in <FIG>, the UE <NUM> may be served by separate RANs 504A and 504B controlled by separate core networks 506A and 506B, where the RAN 504A provides E-UTRA services and RAN 504B provides <NUM> NR services. The UE may operate under only one RAN/CN or both RANs/CNs at a time.

In certain wireless communication systems, a base station (BS) schedules transmissions to a user equipment (UE) by sending the UE a downlink grant. In some examples, as shown in <FIG>, a next generation Node B (gNB) sends a downlink grant to a UE scheduling the UE for a physical downlink shared channel (PDSCH) transmission (e.g., PDSCH <NUM> in <FIG>). The BS may send the downlink grant in downlink control information (DCI) for each scheduled PDSCH. In some examples, the DCI is a fallback DCI (e.g., DCI format 1_0) or a regular DCI (e.g., DCI format 1_1). The BS sends a feedback timing indicator in the DCI. For example, the BS sends a <NUM>-bit PDSCH-to-HARQ (hybrid automatic repeat request (HARQ) feedback timing indicator, referred to as the k1 value. The k1 value may indicate a slot for the UE to provide HARQ acknowledgment (ACK) or negative ACK (NACK) information for the PDSCH transmission. Thus, the k1 defines the processing time for the UE to decode the PDSCH transmission and prepare the ACK/NACK transmission. In some examples, the k1 value indicates a number of slots from the end of the PDSCH transmission to the time at which the UE sends the ACK/NACK to the BS. The k1 values may take values of {<NUM>,<NUM>, <NUM>. As shown in <FIG>, the gNB sends a k1 value of two slots for PDSCH <NUM> and the UE sends the ACK/NACK feedback for the PDSCH <NUM> two slots after the end of the PDSCH <NUM> transmission.

In certain systems, such as NR (new radio or <NUM>) systems, a scheduled PDSCH transmission may be preempted by another PDSCH transmission. For example, NR supports a variety of services including enhanced mobile broadband (eMBB) service and ultra-reliable low-latency communications (URLLC) service. An eMBB PDSCH transmission may be preempted by a URLLC PDSCH transmission. The BS may send a downlink preemption indication (DLPI) to indicate the preempted resources. For example, as shown in <FIG>, when both URLLC and eMBB traffic are present, the gNB sends a DLPI to eMBB UEs (the preempted UE), indicating the time/frequency PDSCH resources that are preempted by URLLC transmissions. The DLPI may be sent at a periodicity of every n slots. The DLPI may indicate the preempted resources in the last n slots. In some examples, the periodicity may take values of n = <NUM>, <NUM>, or <NUM>.

The eMBB UE can improve decoding performance by taking the DLPI (e.g., the indicated preempted resources) into account. However, as shown in <FIG>, if the eMBB UE starts the PDSCH decoding after DLPI is received (e.g., in order to take the DLPI into account in the decoding), there may be insufficient time to finish the UE-side processing (e.g., the PDSCH decoding and ACK/NACK preparation) before the k1 timing signaled by gNB, i.e., before the slot in which the UE needs to send the ACK/NACK information. Therefore, techniques for PDSCH transmission processing in the presence of the DLPI are desirable.

Accordingly, aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for PDSCH processing in presence of DLPI.

In some examples, the BS may ensure that a sufficiently large k1 value is signaled from the gNB to UE to ensure that the DLPI can be incorporated into PDSCH decoding with time to send the HARQ feedback for the PDSCH transmission within the k1 timing.

<FIG> is a flow diagram showing example operations <NUM> for wireless communications, in accordance with certain aspects of the present disclosure. The operations <NUM> may be performed by a BS, such as a BS <NUM> in the wireless communication network <NUM>. Operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., processor <NUM> of <FIG>). Further, the transmission and reception of signals by the BS in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., processor <NUM>) obtaining and/or outputting signals.

The operations <NUM> begin, at <NUM>, by determining a feedback timing indicator (e.g., the k1 value) associated with a PDSCH transmission (e.g., an eMBB PDSCH) to a UE in a first slot. In some examples, the determination is based on a first number of slots from the first slot until transmission of a DLPI to the UE in a second slot and a second number slots for a minimum processing time associated with the UE. The minimum processing time associated with the UE may be the number of slots for the UE to decode the scheduled PDSCH transmission and prepare the HARQ feedback for the scheduled PDSCH transmission. The BS determines the second slot in which the DLPI is transmitted based on the periodicity n associated with the DLPI.

In some examples, the BS selects a feedback timing indicator that is equal to or greater than a sum of the first number of slots and the second number of slots. As shown in <FIG>, in the example of n = <NUM> DLPI periodicity, the gNB schedules eMBB PDSCH <NUM> in the second of the <NUM> slots and preempts with a URLLC PDSCH in that slot. The first number of slots, the number of slots from the end of the PDSCH transmission (e.g., the end PDSCH <NUM> in the example in <FIG>) to the DLPI (<NUM> slots in <FIG>) may be referred to as the delta_t. The second number of slots for the minimum processing time for the UE to process the PDSCH transmission (e.g., PDSCH <NUM> in the example shown in <FIG>) may be referred to as the k1_min. The minimum processing time may be a UE-specific amount that is based on UE capability. In order to ensure that the UE can process the PDSCH transmission and also take into account the DLPI, the gNB may send a timing feedback indicator value <NUM> that is equal to or greater than the sum delta_t + k1_min, as shown in <FIG>.

At <NUM>, the BS sends DCI to the UE scheduling the PDSCH transmission to the UE in the first slot. The DCI includes the feedback timing indicator (e.g., the k1 value). The feedback timing indicator indicates a number of slots after the scheduled PDSCH transmission for the UE to send HARQ feedback (e.g., ACK/NACK) for the scheduled PDSCH transmission.

The BS may then send the scheduled PDSCH (e.g., the eMBB PDSCH) in the slot and the other PDSCH (to the UE or another UE) on the preempted resources in the slot of the scheduled PDSCH. The BS may send the DLPI, indicating the preempted resources by the other PDSCH (e.g., by a URLLC PDSCH). The BS may receive ACK/NACK feedback from the UE for the PDSCH based on the feedback timing indicator.

In some examples, when the DLPI is received in the same slot as the preempted resources (e.g., for n =<NUM> DLPI periodicity), then the UE can take the DLPI into account during the decoding of the PDSCH transmission. When n > <NUM>, then the UE may or may not take the DLPI into account. When the UE receives a feedback timing indicator that is sufficiently large (e.g., k1 ≥ delta_t + k1_min), then the UE may take the DLPI into account for the decoding. For example, the UE buffers the PDSCH transmission and waits until the DLPI is received to process the PDSCH transmission. In some examples, when the k1 is not sufficiently large (e.g., k1 ≤ delta_t + k1_min), the UE may declare an error case. In some examples, when the k1 is not sufficiently large, the UE can proceed with regular decoding and is not expected to take DLPI into account.

<FIG> is a flow diagram showing example operations <NUM> for wireless communications, in accordance with certain aspects of the present disclosure. Operations <NUM> may be performed, for example, by a UE such as a UE <NUM> in the wireless communications network <NUM>. The operations <NUM> may be complimentary operations by the UE to the operations <NUM> performed by the BS. Operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., processor <NUM> of <FIG>). Further, the transmission and reception of signals by the UE in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., processor <NUM>) obtaining and/or outputting signals.

The operations <NUM> may begin, at <NUM>, by receiving DCI scheduling a PDSCH transmission (e.g., an eMBB PDSCH) in a first slot. The DCI includes a feedback timing indicator (e.g., a k1 value) associated with the scheduled PDSCH transmission. At <NUM>, the UE receives the PDSCH transmission in the first slot. At <NUM>, the UE determines how to process the PDSCH transmission based on the feedback timing indicator. At <NUM>, the UE processes the PDSCH transmission based on the determination.

For example, the UE determines whether to begin processing the PDSCH transmission immediately after the PDSCH transmission is received-without waiting for, and without taking into account DLPI, determine buffer the PDSCH transmission and wait for and take into account DLPI to begin processing the PDSCH transmission and account for preempted resources in the decoding, or may declare an error case. The UE may determine how to process the PDSCH based on a first number of slots from the first slot until a second slot in which DLPI is transmitted (e.g., the delta_t) and a second number slots for a minimum processing time associated with the UE (e.g., the k1_min).

As shown in the example call flows <NUM>, <NUM>, and <NUM> in <FIG>, respectively, the BS <NUM> schedules the UE <NUM> for an eMBB PDSCH, at <NUM>, and provides the k1 value for the eMBB PDSCH transmission. At <NUM>, the BS <NUM> sends the scheduled eMBB PDSCH transmission to the UE <NUM>. At <NUM>, the UE <NUM> determines if the k1 value is sufficient (e.g., equal to or larger than the sum of delta_t + 1_min). As shown in <FIG>, when the k1 value is sufficient the UE <NUM> waits for the DLPI (e.g., buffers the PDSCH transmission) at <NUM>. At <NUM>, the UE <NUM> receives the DLPI from the BS <NUM> and then, at <NUM>, the UE <NUM> processes the PDSCH transmission taking the DLPI into account. At <NUM>, based on the k1 timing, the UE sends the HARQ feedback for the PDSCH transmission. As shown in <FIG>, when the k1 value is insufficient (e.g., smaller than the sum of delta_t + k1_min) at <NUM>, the UE processes the PDSCH transmission without waiting for the DLPI. After receiving the DLPI at <NUM>, the UE ignores the DPLI at <NUM> and, at <NUM>, the UE sends the HARQ feedback for the PDSCH transmission based on the k1 timing). Alternatively, as shown in <FIG>, when the k1 value is insufficient, the UE declares an error case at <NUM>.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for PDSCH processing in presence of DLPI. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for determining a feedback timing indicator, code <NUM> for sending DCI scheduling a PDSCH transmission including the feedback timing indicator, and code <NUM> for sending DLPI. In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for determining a feedback timing indicator, circuitry <NUM> for sending DCI scheduling a PDSCH transmission including the feedback timing indicator, and circuitry <NUM> for sending DLPI.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for PDSCH processing in presence of DLPI. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for receiving DCI scheduling a PUSCH transmission including the feedback timing indicator, code <NUM> for receiving the PDSCH transmission; code <NUM> for determining how to process the PDSCH transmission based on the feedback timing indicator; and code <NUM> for processing the PDSCH transmission based on the determination. In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for receiving DCI scheduling a PUSCH transmission including the feedback timing indicator, circuitry <NUM> for receiving the PDSCH transmission; circuitry <NUM> for determining how to process the PDSCH transmission based on the feedback timing indicator; and circuitry <NUM> for processing the PDSCH transmission based on the determination.

For example, instructions for performing the operations described herein and illustrated in <FIG> and <FIG>.

Claim 1:
A method for wireless communications by a user equipment, UE (<NUM>), comprising:
receiving (<NUM>), from a base station (<NUM>), downlink control information, DCI scheduling a physical downlink shared channel, PDSCH transmission in a first slot, the DCI including a feedback timing indicator indicating a first number of slots between the scheduled PDSCH transmission and a third slot for the UE to send hybrid automatic repeat request, HARQ feedback for the scheduled PDSCH transmission;
receiving (<NUM>), from the base station, the PDSCH transmission in the first slot;
processing (<NUM>) the PDSCH transmission wherein processing comprises
determining (<NUM>) whether the first number of slots indicated by the feedback timing indicator is greater than or equal to a sum of a second number of slots from the first slot until a second slot in which a downlink preemption indication, DLPI is transmitted by the base station to the UE and a third number of slots for a processing time associated with the UE, the second slot being determined based on a periodicity associated with the DLPI; and based on the determination,
buffering (<NUM>) the PDSCH on receipt and waiting until the DLPI is received (<NUM>) to decode the PDSCH transmission, when the first number of slots indicated by the feedback timing indicator is greater than or equal to the sum of the second number of slots and the third number of slots; or
decoding the PDSCH transmission, after receiving the PDSCH transmission in the first slot, without waiting and accounting for the DLPI, when the first number of slots indicated by the feedback timing indicator is smaller than the sum of the second number of slots and the third number of slots.