Patent Description:
As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a <NUM> Node B, and/or the like.

The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless communication devices to communicate on a municipal, national, regional, and even global level. <NUM>, which may also be referred to as New radio (NR), is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). <NUM> is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDM with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread ODFM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and <NUM> technologies.

<CIT> discloses a method and an apparatus for transmitting/receiving uplink signaling information and uplink data in a Frequency Division Multiple Access (FDMA) wireless communication system using a single carrier.

<CIT> discloses a method of transmitting data in a wireless communication system for effectively correcting a system error when an error occurs in a control channel.

<CIT> discloses a method and apparatus for transmitting uplink control information in a wireless communication system supporting multiple carriers.

<CIT> discloses a method for discontinuous transmission signaling in a physical uplink shared channel of a wireless communication system. The disclosed method includes puncturing at least a portion of a physical uplink shared channel at a location that would collide with acknowledgement/negative acknowledgement feedback if acknowledgement/negative acknowledgement feedback is transmitted. The method also includes transmitting discontinuous transmission symbols in the punctured portion of the physical uplink shared channel by a user equipment. The method further includes detecting discontinuous transmission symbols on the physical uplink shared channel by an evolved Node B, indicating the user equipment is operating according to a discontinuous transmission signaling mode.

When multiplexing control communications and data communications, a UE may puncture uplink data with ACK/NACK signaling to reduce decoding errors. However, in some radio access technologies, such as <NUM>, puncturing uplink data with ACK/NACK signaling may cause a large performance degradation when the ACK/NACK signaling has a large payload size (e.g., due to ACK/NACK signaling for carrier aggregation, for multiple code block groups, and/or the like). With a large ACK/NACK signaling payload size, rate matching the ACK/NACK signaling around the uplink data may lead to better performance (e.g., throughput, delay, and/or the like) than puncturing the uplink data with the ACK/NACK signaling. However, as indicated above, rate matching the ACK/NACK signaling around the uplink data may lead to decoding errors when the base station does not have information regarding whether to expect receipt of the ACK/NACK signaling.

Advantageous, optional, features are then recited in the accompanying dependent claims.

Some techniques and apparatuses described herein assist with indicating, to a base station, whether ACK/NACK signaling is present in an uplink transmission, thereby enhancing performance by permitting use of rate matching while reducing decoding errors.

In some aspects, a method according to claim <NUM> is provided.

In some aspects, an apparatus according to claim <NUM> is provided.

In some aspects, a computer program product according to claim <NUM> is provided.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.

An access point ("AP") may comprise, be implemented as, or known as a NodeB, a Radio Network Controller ("RNC"), an eNodeB (eNB), a Base Station Controller ("BSC"), a Base Transceiver Station ("BTS"), a Base Station ("BS"), a Transceiver Function ("TF"), a Radio Router, a Radio Transceiver, a Basic Service Set ("BSS"), an Extended Service Set ("ESS"), a Radio Base Station ("RBS"), a Node B (NB), a gNB, a <NUM> NB, a Transmit Receive Point (TRP), or some other terminology.

An access terminal ("AT") may comprise, be implemented as, or be known as an access terminal, a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, user equipment (UE), a user station, a wireless node, or some other terminology. In some aspects, an access terminal may comprise a cellular telephone, a smart phone, a cordless telephone, a Session Initiation Protocol ("SIP") phone, a wireless local loop ("WLL") station, a personal digital assistant ("PDA"), a tablet, a netbook, a smartbook, an ultrabook, a handheld device having wireless connection capability, a Station ("STA"), or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone, a smart phone), a computer (e.g., a desktop), a portable communication device, a portable computing device (e.g., a laptop, a personal data assistant, a tablet, a netbook, a smartbook, an ultrabook), wearable device (e.g., smart watch, smart glasses, smart bracelet, smart wristband, smart ring, smart clothing, and/or the like), medical devices or equipment, biometric sensors/devices, an entertainment device (e.g., music device, video device, satellite radio, gaming device, and/or the like), a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. In some aspects, the node is a wireless node. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link.

Some UEs may be considered machine-type communication (MTC) UEs, which may include remote devices that may communicate with a base station, another remote device, or some other entity. Machine type communications (MTC) may refer to communication involving at least one remote device on at least one end of the communication and may include forms of data communication which involve one or more entities that do not necessarily need human interaction. MTC UEs may include UEs that are capable of MTC communications with MTC servers and/or other MTC devices through Public Land Mobile Networks (PLMN), for example. Examples of MTC devices include sensors, meters, location tags, monitors, drones, robots/robotic devices, and/or the like. In some aspects, MTC devices may be referred to as enhanced MTC (eMTC) devices, LTE category M1 (LTE-M) devices, machine to machine (M2M) devices, and/or the like. Additionally, or alternatively, some UEs may be narrowband Internet of things (NB-IoT) devices.

It is noted that while aspects may be described herein using terminology commonly associated with <NUM> and/or <NUM> wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as <NUM> and later, including <NUM> technologies.

The network <NUM> may be an LTE network or some other wireless network, such as a <NUM> network. A BS is an entity that communicates with user equipment (UEs) and may also be referred to as a base station, a Node B, a gNB, a <NUM> NB, an access point, a TRP, and/or the like.

The terms "eNB", "base station", "gNB", "TRP", "AP", "node B", "<NUM> NB", and "cell" may be used interchangeably herein.

Some UEs may be considered evolved or enhanced machine-type communication (eMTC) UEs. Some UEs may be considered Internet-of-Things (IoT) devices.

In some aspects, a UE <NUM> may use ACK/NACK signaling to indicate whether communications from a base station <NUM> were properly received and/or decoded by the UE <NUM>. As described in more detail elsewhere herein, a UE <NUM> determines whether ACK/NACK signaling is to be included in an uplink transmission in a portion of uplink resources allocated for a data channel, generates a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, and transmits the reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission. The base station <NUM> receives the reference signal, determines whether the ACK/NACK signaling was received in the uplink transmission based at least in part on the reference signal, and decodes the ACK/NACK signaling when the ACK/NACK signaling is received.

While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communication systems, such as <NUM> technologies.

In some aspects, <NUM> may refer to radios configured to operate according to a new air interface (e.g., other than Orthogonal Frequency Divisional Multiple Access (OFDMA)-based air interfaces) or fixed transport layer (e.g., other than Internet Protocol (IP)). In aspects, <NUM> may utilize OFDM with a CP (herein referred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDM on the uplink, may utilize CP-OFDM on the downlink and include support for half-duplex operation using TDD. In aspects, <NUM> may, for example, utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink and include support for half-duplex operation using TDD. <NUM> may include Enhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g., <NUM> megahertz (MHz) and beyond), millimeter wave (mmW) targeting high carrier frequency (e.g., <NUM> gigahertz (GHz)), massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra reliable low latency communications (URLLC) service.

A single component carrier bandwidth of <NUM> may be supported. <NUM> resource blocks may span <NUM> sub-carriers with a sub-carrier bandwidth of <NUM> kilohertz (kHz) over a <NUM> duration. Each radio frame may include <NUM> subframes with a length of <NUM>. Consequently, each subframe may have a length of <NUM>. Each subframe may indicate a link direction (e.g., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data. UL and DL subframes for <NUM> may be as described in more detail below with respect to <FIG>.

Alternatively, <NUM> may support a different air interface, other than an OFDM-based interface. <NUM> networks may include entities such central units or distributed units.

The RAN may include a central unit (CU) and distributed units (DUs). A <NUM> BS (e.g., gNB, <NUM> Node B, Node B, transmit receive point (TRP), access point (AP)) may correspond to one or multiple BSs. <NUM> cells can be configured as access cells (ACells) or data only cells (DCells). For example, the RAN (e.g., a central unit or distributed unit) can configure the cells. DCells may be cells used for carrier aggregation or dual connectivity, but not used for initial access, cell selection/reselection, or handover. In some cases, DCells may not transmit synchronization signals-in some case cases DCells may transmit SS. <NUM> BSs may transmit downlink signals to UEs indicating the cell type. Based at least in part on the cell type indication, the UE may communicate with the <NUM> BS. For example, the UE may determine <NUM> BSs to consider for cell selection, access, handover, and/or measurement based at least in part on the indicated cell type.

Transmit processor <NUM> may also process system information (e.g., for semi-static resource partitioning information (SRPI), and/or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and/or the like) and provide overhead symbols and control symbols. Transmit processor <NUM> may also generate reference symbols for reference signals (e.g., the CRS) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS)). According to certain aspects described in more detail below, the synchronization signals can be generated with location encoding to convey additional information.

A receive (RX) processor <NUM> may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE <NUM> to a data sink <NUM>, and provide decoded control information and system information to a controller/processor <NUM>. A channel processor may determine RSRP, RSSI, RSRQ, CQI, and/or the like.

Controllers/processors <NUM> and <NUM> and/or any other component(s) in <FIG> may direct the operation at base station <NUM> and UE <NUM>, respectively, to perform acknowledgement or negative acknowledgement (ACK/NACK) signaling using a reference signal. For example, controller/processor <NUM> and/or other processors and modules at base station <NUM>, may perform or direct operations of UE <NUM> to perform acknowledgement or negative acknowledgement (ACK/NACK) signaling using a reference signal. For example, controller/processor <NUM> and/or other controllers/processors and modules at BS <NUM> may perform or direct operations of, for example, method <NUM> of <FIG>, method <NUM> of <FIG>, and/or other methods as described herein. In some aspects, one or more of the components shown in <FIG> may be employed to perform example method <NUM> of <FIG>, method <NUM> of <FIG>, and/or other methods for the techniques described herein. Memories <NUM> and <NUM> may store data and program codes for BS <NUM> and UE <NUM>, respectively.

<FIG> is a diagram <NUM> showing an example of a DL-centric subframe or wireless communication structure.

The DL-centric subframe may also include an UL short burst portion <NUM>. The UL short burst portion <NUM> may sometimes be referred to as an UL burst, an UL burst portion, a common UL burst, a short burst, an UL short burst, a common UL short burst, a common UL short burst portion, and/or various other suitable terms. In some aspects, the UL short burst portion <NUM> may include one or more reference signals. Additionally, or alternatively, the UL short burst portion <NUM> may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the UL short burst portion <NUM> may include feedback information corresponding to the control portion <NUM> and/or the data portion <NUM>. Nonlimiting examples of information that may be included in the UL short burst portion <NUM> include an ACK signal (e.g., a physical uplink control channel (PUCCH) ACK, a physical uplink shared channel (PUSCH) ACK, an immediate ACK), a NACK signal (e.g., a PUCCH NACK, a PUSCH NACK, an immediate NACK), a scheduling request (SR), a buffer status report (BSR), a HARQ indicator, a channel state indication (CSI), a channel quality indicator (CQI), a sounding reference signal (SRS), a demodulation reference signal (DMRS), PUSCH data, and/or various other suitable types of information. The UL short burst portion <NUM> may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests, and various other suitable types of information. In some aspects, a DMRS may be used to indicate whether ACK/NACK signaling is present in an uplink transmission, as described in more detail elsewhere herein.

The foregoing is one example of a DL-centric wireless communication structure, and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

<FIG> is a diagram <NUM> showing an example of an UL-centric subframe or wireless communication structure. The UL-centric subframe may include a control portion <NUM>. The control portion <NUM> may exist in the initial or beginning portion of the UL-centric subframe. The control portion <NUM> in <FIG> may be similar to the control portion <NUM> described above with reference to <FIG>. In some configurations, the control portion <NUM> may be a physical DL control channel (PDCCH).

The UL-centric subframe may also include an UL long burst portion <NUM>. The UL long burst portion <NUM> may sometimes be referred to as the payload of the UL-centric subframe. The UL portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS).

The UL-centric subframe may also include an UL short burst portion <NUM>. The UL short burst portion <NUM> in <FIG> may be similar to the UL short burst portion <NUM> described above with reference to <FIG>, and may include any of the information described above in connection with <FIG>. The foregoing is one example of an UL-centric wireless communication structure and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

<FIG> is a diagram illustrating an example <NUM> of acknowledgement or negative acknowledgement (ACK/NACK) signaling.

In some radio access technologies, such as LTE, when a UE is scheduled to transmit both control transmissions (e.g., PUCCH transmissions) and data transmissions (e.g., PUSCH transmissions), in the same wireless communication structure (e.g., a subframe), the UE may multiplex the control transmissions and the data transmissions prior to performing a discrete Fourier transform (DFT) operation. This may be referred to as piggybacking, and may increase throughput by multiplexing the transmissions.

As shown in <FIG>, in some aspects, the UE may rate match some control transmissions around the data transmissions. For example, the UE may rate match a channel quality indicator (CQI) / pre-coding matrix indicator (PMI) <NUM> around uplink data <NUM> (e.g., PUSCH transmissions). Additionally, or alternatively, the UE may rate match a rank indicator (RI) <NUM> around the uplink data <NUM>. In some aspects, the UE may puncture the uplink data <NUM> with ACK/NACK signaling <NUM>. Additionally, or alternatively, some resource element may be used for a demodulation reference signal (DMRS) <NUM>.

In some aspects, the UE may rate match the CQI/PMI <NUM> and/or the RI <NUM> around the uplink data <NUM> because a base station communicating with the UE stores information regarding whether to expect receipt of the CQI/PMI <NUM> and/or the RI <NUM> from the UE. For example, periodic transmission of CQI/PMI <NUM> and/or RI <NUM> by the UE may be configured during radio resource control (RRC) configuration between the UE and the base station. Additionally, or alternatively, aperiodic transmission of CQI/PMI <NUM> and/or RI <NUM> by the UE may be configured using an uplink grant sent from the base station to the UE. In this case, if the UE receives the uplink grant, then the CQI/PMI <NUM> and/or RI <NUM> may be transmitted according to the uplink grant. If the UE does not receive the uplink grant, then the UE may not transmit control or data communications corresponding to the uplink grant, in which case the base station will not receive the aperiodic CQI/PMI <NUM> and/or RI <NUM>, and so will not have any decoding errors for the CQI/PMI <NUM> and/or RI <NUM>.

In some aspects, the UE may puncture the uplink data <NUM> with the ACK/NACK signaling <NUM> to reduce decoding errors as compared to rate matching the ACK/NACK signaling <NUM> around the uplink data <NUM>. Rate matching the ACK/NACK signaling <NUM> around the uplink data <NUM> may result in decoding errors because the base station does not store information regarding whether to expect receipt of the ACK/NACK signaling <NUM> (e.g., the base station does not know whether the UE will receive a downlink grant or not). For example, if a base station is configured to assume that the UE rate matches the ACK/NACK signaling <NUM> around the uplink data <NUM>, and the UE does not transmit the ACK/NACK signaling <NUM> (e.g., due to a missed downlink grant), then the base station may fail to decode the uplink data <NUM> due to a log likelihood ratio (LLR) location mismatch. Thus, puncturing the uplink data <NUM> with the ACK/NACK signaling <NUM> may reduce decoding errors.

However, in some radio access technologies, such as <NUM>, puncturing the uplink data <NUM> with the ACK/NACK signaling <NUM> may cause a larger performance degradation as compared to other radio access technologies, such as LTE. For example, the ACK/NACK signaling <NUM> may have a larger payload size due to the use of carrier aggregation. Additionally, or alternatively, the ACK/NACK signaling <NUM> may have a larger payload size due to the use of multiple downlink code block groups with multiple corresponding ACKs/NACKs (e.g., one ACK/NACK for each code block group). With the larger ACK/NACK signaling payload size, rate matching the ACK/NACK signaling <NUM> around the uplink data <NUM> may lead to better performance (e.g., throughput, delay, and/or the like) than puncturing the uplink data <NUM> with the ACK/NACK signaling <NUM>. However, as indicated above, rate matching the ACK/NACK signaling <NUM> around the uplink data <NUM> may lead to decoding errors when the base station does not have information regarding whether to expect receipt of the ACK/NACK signaling <NUM>. Techniques described herein assist with indicating, to the base station, whether ACK/NACK signaling <NUM> is present in an uplink transmission, thereby enhancing performance by permitting use of rate matching while reducing decoding errors.

<FIG> is a diagram illustrating another example <NUM> of ACK/NACK signaling using a reference signal. As shown in <FIG>, a UE <NUM> may communicate with a base station <NUM>. In some aspects, the UE <NUM> may correspond to one or more UEs described elsewhere herein, such as UE <NUM> of <FIG> and/or the like. Additionally, or alternatively, the base station <NUM> may correspond to one or more base stations described elsewhere herein, such as base station <NUM> of <FIG> and/or the like.

At <NUM>, the UE <NUM> determines whether ACK/NACK signaling is to be included in an uplink transmission in a portion of uplink resources allocated for a data channel. In some aspects, the portion of uplink resources allocated for the data channel is a PUSCH. In some aspects, the UE <NUM> may include ACK/NACK signaling in the uplink transmission when a downlink grant is received by the UE <NUM>. For example, the UE <NUM> may include an ACK in the uplink transmission when downlink data, corresponding to the downlink grant, is received and successfully decoded. Additionally, or alternatively, the UE <NUM> may include a NACK in the uplink transmission when downlink data, corresponding to the downlink grant, is not received or is not successfully decoded. In some aspects, the UE <NUM> may not include ACK/NACK signaling in the uplink transmission when a downlink grant is missed by the UE <NUM> (e.g., because the UE <NUM> is unaware of downlink data to be acknowledged or negatively acknowledged).

At <NUM>, the UE <NUM> generates a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, and transmits the reference signal. Further, UE <NUM> modulates the reference signal to indicate whether the ACK/NACK signaling is present in the uplink transmission. Additionally, one or more cyclic shifts or one or more phase rampings of the reference signal indicates whether the ACK/NACK signaling is present in the uplink transmission. For example, the UE <NUM> may modify one or more cyclic shifts and/or one or more phase rampings of the reference signal to indicate whether the ACK/NACK signaling is present in the uplink transmission.

The reference signal includes a single symbol. For example, the reference signal may be a DMRS with one symbol. In this case, the single symbol indicates whether the ACK/NACK signaling is present in the uplink transmission. For example, the single symbol may be a sequence (e.g., a DMRS sequence) having a cyclic shift or a phase ramping that indicates whether the ACK/NACK signaling is present in the uplink transmission. In some aspects, a first cyclic shift or a first phase ramping of the reference signal (e.g., the single symbol) may indicate that ACK/NACK signaling is present in the uplink transmission, and a second cyclic shift or a second phase ramping of the reference signal may indicate that ACK/NACK signaling is not present in the uplink transmission.

Referring to the example at <NUM>, a first cyclic shift is shown as CS(<NUM>), indicating no cyclic shift for the sequence, and a second cyclic shift is shown as CS(N/<NUM>), indicating a cyclic shift of N/<NUM>, where N is a length of the sequence. In some aspects, a cyclic shift of zero may indicate that ACK/NACK signaling is present in the uplink transmission, and a second cyclic shift of N/<NUM> may indicate that ACK/NACK signaling is not present in the uplink transmission. In some aspects, a cyclic shift of N/<NUM> may indicate that ACK/NACK signaling is present in the uplink transmission, and a second cyclic shift of zero may indicate that ACK/NACK signaling is not present in the uplink transmission.

In some aspects, the reference signal includes at least two symbols. For example, the reference signal may be a DMRS with two symbols. In this case, the two symbols may indicate whether the ACK/NACK signaling is present in the uplink transmission. For example, the UE <NUM> may generate the two symbols with a same cyclic shift and/or phase ramping or different cyclic shifts and/or phase rampings to indicate whether the ACK/NACK signaling is present in the uplink transmission. In some aspects, a first pair of cyclic shifts or a first pair of phase rampings of the two symbols may indicate that ACK/NACK signaling is present in the uplink transmission, and a second pair of cyclic shifts or a second pair of phase rampings of the two symbols may indicate that ACK/NACK signaling is not present in the uplink transmission.

Referring again to the example at <NUM>, a first cyclic shift for the first symbol is shown as CS(<NUM>), indicating no cyclic shift for the sequence used for the first symbol, and a second cyclic shift is shown as CS(N/<NUM>), indicating a cyclic shift of N/<NUM> for the sequence used for the second symbol. In this case, different cyclic shifts are used for the two symbols of the reference signal (e.g., zero and N/<NUM>). In some aspects, different cyclic shifts for the two symbols may indicate that ACK/NACK signaling is present in the uplink transmission, and the same cyclic shift for the two symbols (e.g., zero and zero, N/<NUM> and N/<NUM>, and/or the like) may indicate that ACK/NACK signaling is not present in the uplink transmission. In some aspects, the same cyclic shift for the two symbols may indicate that ACK/NACK signaling is present in the uplink transmission, and different cyclic shifts for the two symbols may indicate that ACK/NACK signaling is not present in the uplink transmission.

Referring to the example at <NUM>, in some aspects, the UE <NUM> may use <NUM> bit of information (e.g., a binary indication of whether ACK/NACK signaling is present in the uplink transmission) to modulate half of the entries of the base DMRS sequence (e.g., shown as "Y"). In this way, the UE <NUM> may modulate the reference signal in the time domain (e.g., using a cyclic shift) or in the frequency domain (e.g., using phase ramping, such as phase ramping with a slope of pi). In some aspects, the UE <NUM> may modulate the reference signal to deliver one bit of information, as described above. Additionally, or alternatively, the UE <NUM> modulates the reference signal to deliver more than one bit of information, such as information indicating a quantity of ACK/NACK signaling bits transmitted by the UE <NUM>. For example, a first cyclic shift or a first phase ramping of the reference signal may indicate that ACK/NACK signaling is not present in the uplink transmission, a second cyclic shift or a second phase ramping of the reference signal may indicate that one bit of ACK/NACK signaling is present in the uplink transmission, a third cyclic shift or a third phase ramping of the reference signal may indicate that two bits of ACK/NACK signaling are present in the uplink transmission, a fourth cyclic shift or a fourth phase ramping of the reference signal may indicate that three bits of ACK/NACK signaling are present in the uplink transmission, and/or the like.

In some aspects, the indication in the reference signal of whether ACK/NACK signaling is present in the uplink transmission may be an indication of whether uplink data is rate matched around the ACK/NACK signaling in the uplink transmission. In some aspects, the indication in the reference signal of whether ACK/NACK signaling is present in the uplink transmission may be an indication of whether uplink data is punctured by the ACK/NACK signaling in the uplink transmission. For example, ACK/NACK signaling between the UE <NUM> and the base station <NUM> may be configured for rate matching (e.g., by default, based at least in part on an RRC configuration, and/or the like). In this case, the reference signal may indicate whether uplink data is rate matched around the ACK/NACK signaling in the uplink transmission. As another example, ACK/NACK signaling between the UE <NUM> and the base station <NUM> may be configured for puncturing (e.g., by default, based at least in part on an RRC configuration, and/or the like). In this case, the reference signal may indicate whether uplink data is punctured by the ACK/NACK signaling in the uplink transmission.

At <NUM>, the base station <NUM> receives the reference signal, determines whether the ACK/NACK signaling was received in the uplink transmission based at least in part on the reference signal, and decodes the ACK/NACK signaling and/or uplink data included in the uplink transmission based at least in part on whether the ACK/NACK signaling is present. Further, the base station <NUM> decodes the ACK/NACK signaling when the ACK/NACK signaling is received. Additionally, or alternatively, the base station <NUM> may decode uplink data in the uplink transmission based at least in part on whether the ACK/NACK signaling was received.

In some aspects, when the ACK/NACK signaling is received by the base station <NUM>, the base station <NUM> may decode uplink data from a set of resource elements (REs) other than resource elements in which the ACK/NACK signaling is received. For example, the uplink data may be included in a first set of REs, in the uplink transmission, that are rate matched around a second set of REs, in the uplink transmission, that include the ACK/NACK signaling. Additionally, or alternatively, the second set of REs may puncture some uplink data in the uplink transmission, and uplink data may remain in the first set of REs. In either case, when the reference signal indicates that ACK/NACK signaling is present in the uplink transmission, the base station <NUM> may decode the uplink data from the first set of REs (e.g., and may not use the second set of REs for decoding uplink data). In some aspects, the base station <NUM> may apply a rule to collect log likelihood ratio (LLR) results from the first set of REs that include uplink data (and not the second set of REs that include ACK/NACK signaling or other REs that include, for example, CQI, PMI, RI, and/or the like). In some aspects, the rule may be different depending on whether puncturing or rate matching is used for ACK/NACK signaling in the uplink transmission.

In some aspects, when the ACK/NACK signaling is not received by the base station <NUM>, the base station <NUM> may decode uplink data from a set of resource elements (REs) including resource elements in which the ACK/NACK signaling would otherwise be received. For example, when ACK/NACK signaling is not present in an uplink transmission, the UE <NUM> may include uplink data in the first set of REs and the second set of REs (e.g., as described above), where the second set of REs would otherwise be used for ACK/NACK signaling if ACK/NACK signaling were present in the uplink transmission. In this case, when the reference signal indicates that ACK/NACK signaling is not present in the uplink transmission, the base station <NUM> may decode the uplink data from the first set of REs (e.g., uplink data REs) and the second set of REs (e.g., ACK/NACK signaling REs). In some aspects, the base station <NUM> may apply a rule to collect log likelihood ratio (LLR) results from the first set of REs and the second set of REs that include uplink data (and not other REs that include, for example, CQI, PMI, RI, and/or the like).

In some aspects, the UE <NUM> and/or the base station <NUM> may enable or disable the indication of ACK/NACK signaling using a reference signal. For example, if a UE <NUM> is associated with good channel conditions (e.g., based on an indication of channel conditions, such as RSRP, RSRQ, and/or the like, satisfying a threshold), then such reference signal indications may be disabled by the UE <NUM> (e.g., autonomously or based at least in part on an instruction from the base station <NUM>). In this way, network resources may be conserved.

Although techniques are described above in connection with using a reference signal to indicate whether ACK/NACK signaling is present in an uplink transmission, other techniques may be used. For example, in some aspects, dedicated resource elements may be used to indicate whether ACK/NACK signaling is present in an uplink transmission. In some aspects, the dedicated resource elements may be indicated in configuration information communicating between the base station <NUM> and the UE <NUM> (e.g., in an RRC message). In some aspects, the dedicated resource elements may be encoded for repetition (e.g., to repeat <NUM> bit of information in multiple resource elements). Additionally, or alternatively, the dedicated resource elements may be modulated using a dedicated modulation order (e.g., QPSK), which may be signaled (e.g., in an RRC message).

Additionally, or alternatively, one or more dedicated resource elements may indicate a payload size of the ACK/NACK signaling. Additionally, or alternatively, one or more dedicated resource elements may indicate the communications (e.g., downlink grants) to which the ACK/NACK signaling corresponds (e.g., a bitmap that maps ACK/NACK signals to downlink grants). For example, if the base station <NUM> schedules four downlink grants for the UE <NUM> (e.g., in <NUM> slots, in <NUM> carriers, in a combination of <NUM> slots and <NUM> carriers, etc.), then the UE <NUM> may indicate which downlink grants were received and/or missed using dedicated resource elements. For example, signaling a bitmap of <NUM> may indicate that the UE <NUM> sends ACK/NACK signaling for the first, second, and fourth downlink grants, and that the UE <NUM> missed the third downlink grant and did not send ACK/NACK signaling for the third downlink grant. In this way, the base station <NUM> may send downlink retransmissions according to which downlink grants were missed by the UE <NUM>.

Additionally, or alternatively, the base station <NUM> and/or the UE <NUM> may use an RRC message to semi-statically configure the payload size of the ACK/NACK signaling and/or the bitmap that maps ACK/NACK signals to downlink grants. In this way, resource elements may be conserved and/or used for other purposes. For example, if the UE <NUM> is configured with two component carriers in transmission mode <NUM> (e.g., rank <NUM>), then the UE <NUM> may have four bits in the ACK/NACK signaling fields. The first two bits may correspond to the first component carrier and the second two bits corresponding to the second component carrier. In this case, even if the UE <NUM> is only scheduled on one component carrier, then the UE <NUM> will include NACK signaling in the corresponding field to resolve the payload size ambiguity at the base station <NUM>. In other words, the payload size may be fixed based on the configuration indicated by the base station <NUM>. In this case, the UE <NUM> may either send nothing if the UE <NUM> missed both downlink grants on both component carriers, or may send four bits if the UE <NUM> received at least one downlink grant. In this scenario, there may be ambiguity at the base station <NUM> regarding whether to expect receipt of ACK/NACK signaling if the UE <NUM> misses both downlink grant on the two component carriers. In this case, the ACK/NACK signaling will not be transmitted from the UE <NUM>, but the base station <NUM> will still expect <NUM> bits of ACK/NACK signaling. However, this situation can be resolved to reduce errors by using different reference signal (e.g., DMRS) sequences to indicate to the base station <NUM> whether ACK/NACK signaling has been transmitted, as described in more detail elsewhere herein.

Additionally, or alternatively, the base station <NUM> may bundle downlink grants and uplink grants. In this way, if the UE <NUM> receives the downlink grant, the UE <NUM> will also receive the uplink grant, and will transmit an uplink transmission based at least in part on receiving the uplink grant. In this case, the base station <NUM> will expect receipt of ACK/NACK signaling because if the base station <NUM> receives an uplink transmission corresponding to the uplink grant, then the base station <NUM> determines that the UE <NUM> also received the downlink grant. If the UE <NUM> does not receive the downlink grant, then the UE <NUM> will also not receive the uplink grant, and will not transmit an uplink transmission, so the base station <NUM> will not fail to decode the uplink transmission.

By indicating to the base station <NUM> whether ACK/NACK signaling is present in an uplink transmission, the UE <NUM> may improve performance by permitting use of rate matching while reducing decoding errors, as described elsewhere herein.

<FIG> and <FIG> are diagrams illustrating another example <NUM> of ACK/NACK signaling. <FIG> and <FIG> show an example of a special rate matching pattern for ACK/NACK signaling that reduces decoding errors at the base station. In <FIG> and <FIG>, each block represents a resource element (RE) along a symbol period.

As shown in <FIG>, when the UE does not use the special rate matching pattern, the UE may begin filling ACK/NACK signaling REs (e.g., one or more REs that the base station assumes includes ACK/NACK signaling) with uplink data (e.g., shown as PUSCH <NUM>, PUSCH <NUM>, and so on) instead of ACK/NACK signaling. At <NUM>, without using the special rate matching pattern, if the UE receives a downlink grant and sends an ACK, and the base station (BS) assumes that the ACK is sent, then the base station will be able to decode the uplink data (e.g., on the PUSCH) because the first bit of uplink data (PUSCH <NUM>) is received in the RE in which the base station expects to receive the first bit of uplink data. However, at <NUM>, without using the special rate matching pattern, if the UE misses the downlink grant and does not send an ACK, and the UE instead sends the first bit of uplink data (PUSCH <NUM>) in the RE in which the base station is expecting ACK/NACK signaling, then the base station will not be able to decode the uplink data because the base station assumes that the RE that includes the first bit of uplink data (shown as PUSCH <NUM>) includes an ACK, and thus will not include this RE when decoding the uplink data. Thus, the base station will start decoding with PUSCH <NUM> rather than PUSCH <NUM>, and the decoding will fail. This rate matching pattern results in an offset in bit ordering, resulting in a decoding failure of uplink data.

As shown in <FIG>, when the UE uses the special rate matching pattern, the UE may first rate match around ACK/NACK signaling REs (e.g., by assuming that ACK/NACK signaling will be sent) until all uplink data REs (e.g., PUSCH REs) are filled. Then, if the UE receives a downlink grant, the UE may map ACK/NACK signaling to ACK/NACK signaling REs. If the UE misses the downlink grant, then the UE may map modulated uplink data symbols (e.g., PUSCH symbols) onto the ACK/NACK signaling REs (e.g., REs that would otherwise be used for ACK/NACK signaling if the UE received the downlink grant).

At <NUM>, if the UE receives a downlink grant and sends an ACK, and the base station assumes that the ACK is sent, then the base station will be able to decode the uplink data (e.g., on the PUSCH) because the first bit of uplink data (PUSCH <NUM>) is received in the RE in which the base station expects to receive the first bit of uplink data. Furthermore, at <NUM>, if the UE misses the downlink grant and does not send an ACK, and the base station assumes that the ACK is sent, then the base station will still be able to decode the uplink data because the base station will start decoding with PUSCH <NUM> after skipping the ACK/NACK signaling RE, which includes PUSCH <NUM>. This special rate matching pattern results in a correct bit ordering, resulting in a successful decoding of uplink data.

Other examples are possible and may differ from what was described with regard to <FIG> and <FIG>.

<FIG> is a flow chart of a method <NUM> of wireless communication. The method is performed by a UE (e.g., the UE <NUM> of <FIG>, the UE <NUM> of <FIG>, the apparatus <NUM>/<NUM>' of <FIG>/<FIG>, and/or the like).

At <NUM>, the UE determines whether ACK/NACK signaling is to be included in an uplink transmission. In particular, the UE determines whether ACK/NACK signaling is to be included in an uplink transmission in a portion of uplink resources allocated for a data channel, as described in more detail above in connection with <FIG>.

At <NUM>, the UE generates a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission. In particular, the UE generates a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, as described in more detail above in connection with <FIG>.

At <NUM>, the UE transmits the reference signal. In particular, the UE transmits the reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, as described in more detail above in connection with <FIG>.

Method <NUM> may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other methods described elsewhere herein.

In some aspects, the reference signal is modulated to indicate whether the ACK/NACK signaling is present in the uplink transmission. In some aspects, one or more cyclic shifts or one or more phase rampings of the reference signal indicate whether the ACK/NACK signaling is present in the uplink transmission.

In some aspects, a single symbol of the reference signal indicates whether the ACK/NACK signaling is present in the uplink transmission. In some aspects, the single symbol includes a sequence having a cyclic shift or a phase ramping that indicates whether the ACK/NACK signaling is present in the uplink transmission.

In some aspects, at least two symbols of the reference signal indicate whether the ACK/NACK signaling is present in the uplink transmission. In some aspects, the at least two symbols are generated with a same cyclic shift or phase ramping or different cyclic shifts or phase rampings to indicate whether the ACK/NACK signaling is present in the uplink transmission.

In some aspects, the reference signal is a demodulation reference signal. In some aspects, the reference signal indicates whether uplink data is rate matched around the ACK/NACK signaling in the uplink transmission. In some aspects, the reference signal indicates whether uplink data is punctured by the ACK/NACK signaling in the uplink transmission. In some aspects, a payload size of the ACK/NACK signaling is indicated using one or more dedicated resource elements. In some aspects, the portion of uplink resources allocated for the data channel is a physical uplink shared channel.

Although <FIG> shows example blocks of a method of wireless communication, in some aspects, the method may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those shown in <FIG>. Additionally, or alternatively, two or more blocks shown in <FIG> may be performed in parallel.

<FIG> is a flow chart of a method <NUM> of wireless communication. The method is performed by a base station (e.g., the base station <NUM> of <FIG>, the base station <NUM> of <FIG>, the apparatus <NUM>/<NUM>' of <FIG>/<FIG>, and/or the like).

At <NUM>, the base station receives a reference signal that indicates whether ACK/NACK signaling is present in an uplink transmission. In particular, the base station receives a reference signal that indicates whether ACK/NACK signaling is present in an uplink transmission in a portion of uplink resources allocated for a data channel, as described in more detail above in connection with <FIG>.

At <NUM>, the base station determines whether the ACK/NACK signaling was received in the uplink transmission. In particular, the base station determines whether the ACK/NACK signaling was received in the uplink transmission based at least in part on the reference signal, as described in more detail above in connection with <FIG>.

At <NUM>, the base station decodes the ACK/NACK signaling when the ACK/NACK signaling is received. In particular, the base station decodes the ACK/NACK signaling when the ACK/NACK signaling is received, as described in more detail above in connection with <FIG>.

In some aspects, the base station may decode uplink data in the uplink transmission based at least in part on whether the ACK/NACK signaling was received. In some aspects, when the ACK/NACK signaling is received, the uplink data is decoded from a set of resource elements other than resource elements in which the ACK/NACK signaling is received. In some aspects, a set of resource elements are decoded as the ACK/NACK signaling or uplink data based at least in part on the indication in the reference signal.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different modules/means/components in an example apparatus <NUM>. The apparatus <NUM> is a UE. In some aspects, the apparatus <NUM> includes a reception module <NUM>, a determination module <NUM>, a generation module <NUM>, a transmission module <NUM>, and/or the like.

The reception module <NUM> may receive data <NUM>, such as a downlink grant, from a base station <NUM>, and may provide data <NUM> to the determination module <NUM> to indicate whether a downlink grant has been received. The determination module <NUM> determines whether ACK/NACK signaling is to be included in an uplink transmission in a portion of uplink resources allocated for a data channel. For example, the determination module <NUM> may determine that ACK/NACK signaling is to be included in the uplink transmission when the downlink grant is received, and may determine that ACK/NACK signaling is not to be included in the uplink transmission when the downlink grant is not received. The determination module <NUM> may provide data <NUM> to the generation module <NUM> to indicate whether to include the ACK/NACK signaling in the uplink transmission. The generation module <NUM> generates a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, and may provide data <NUM>, such as the reference signal, to the transmission module <NUM>. The transmission module <NUM> transmits the reference signal and/or the uplink transmission, as data <NUM>, to the base station <NUM>.

The apparatus may include additional modules that perform each of the blocks of the algorithm in the aforementioned flow chart of <FIG>. As such, each block in the aforementioned flow chart of <FIG> may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The apparatus <NUM>' is a UE.

The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware modules, represented by the processor <NUM>, the modules <NUM>, <NUM>, <NUM>, and/or <NUM>, and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception module <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission module <NUM>, and based at least in part on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system further includes at least one of the modules <NUM>, <NUM>, <NUM>, and/or <NUM>. The modules may be software modules running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware modules coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the UE <NUM> and may include the memory <NUM> and/or at least one of the TX MIMO processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM>.

The apparatus <NUM>/<NUM>' for wireless communication includes means for determining whether ACK/NACK signaling is to be included in an uplink transmission in a portion of uplink resources allocated for a data channel, means for generating a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, means for transmitting the reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, and/or the like. The aforementioned means may be one or more of the aforementioned modules of the apparatus <NUM> and/or the processing system <NUM> of the apparatus <NUM>' configured to perform the functions recited by the aforementioned means. As described supra, the processing system <NUM> may include the TX MIMO processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM>. As such, in one configuration, the aforementioned means may be the TX MIMO processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM> configured to perform the functions recited by the aforementioned means.

Other examples are possible and may differ from what was described in connection with <FIG>.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different modules/means/components in an example apparatus <NUM>. The apparatus <NUM> is a base station. In some aspects, the apparatus <NUM> includes a reception module <NUM>, a determination module <NUM>, a decoding module <NUM>, a transmission module <NUM>, and/or the like.

The reception module <NUM> receives data <NUM> from a UE <NUM>. The data <NUM> includes a reference signal that indicates whether ACK/NACK signaling is present in an uplink transmission in a portion of uplink resources allocated for a data channel. The reception module <NUM> may provide data <NUM>, such as the reference signal, to the determination module <NUM>. The determination module <NUM> determines whether the ACK/NACK signaling was received in the uplink transmission based at least in part on the reference signal, and may provide data <NUM>, such as an indication of whether the ACK/NACK signaling was received, to the decoding module <NUM>. The decoding module <NUM> decodes the ACK/NACK signaling and/or uplink data in the uplink transmission based at least in part on whether the ACK/NACK signaling was received. In some aspects, the decoding module <NUM> may provide data <NUM>, such as information associated with a result of the decoding to the transmission module <NUM>. The transmission module <NUM> may provide data <NUM> to the UE <NUM>, such as the information associated with the result of the decoding.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The apparatus <NUM>' is a base station.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception module <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the transmission module <NUM>, and based at least in part on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system further includes at least one of the modules <NUM>, <NUM>, <NUM>, and/or <NUM>. The modules may be software modules running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware modules coupled to the processor <NUM>, or some combination thereof. The processing system <NUM> may be a component of the base station <NUM> and may include the memory <NUM> and/or at least one of the TX MIMO processor <NUM>, the RX processor <NUM>, and/or the controller/processor <NUM>.

The apparatus <NUM>/<NUM>' for wireless communication includes means for receiving a reference signal that indicates whether ACK/NACK signaling is present in an uplink transmission in a portion of uplink resources allocated for a data channel, means for determining whether the ACK/NACK signaling was received in the uplink transmission based at least in part on the reference signal, means for decoding the ACK/NACK signaling when the ACK/NACK signaling is received, means for decoding uplink data in the uplink transmission based at least in part on whether the ACK/NACK signaling was received, and/or the like. The aforementioned means may be one or more of the aforementioned modules of the apparatus <NUM> and/or the processing system <NUM> of the apparatus <NUM>' configured to perform the functions recited by the aforementioned means. As described supra, the processing system <NUM> may include the TX MIMO processor <NUM>, the receive processor <NUM>, and/or the controller/processor <NUM>. As such, in one configuration, the aforementioned means may be the TX MIMO processor <NUM>, the receive processor <NUM>, and/or the controller/processor <NUM> configured to perform the functions recited by the aforementioned means.

It is understood that the specific order or hierarchy of blocks in the processes / flow charts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes / flow charts may be rearranged.

Claim 1:
A method (<NUM>) of wireless communication performed by a user equipment, UE, comprising:
determining (<NUM>) whether acknowledgement or negative acknowledgement, ACK/NACK, signaling is to be included in an uplink transmission in a portion of uplink resources allocated for a data channel;
generating (<NUM>) a reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission, wherein the reference signal includes a single symbol; and wherein a single symbol of the reference signal indicates whether the ACK/NACK signaling is present in the uplink transmission, and wherein a phase ramping of a plurality of phase rampings applied to the single symbol indicates whether the ACK/NACK signaling is present or not present in the uplink transmission; and wherein the reference signal is modulated to indicate more than one bit of information concerning the quantity of ACK/NACK signaling bits transmitted by the UE; and
transmitting (<NUM>) the reference signal that indicates whether the ACK/NACK signaling is present in the uplink transmission.