Codeword determination for acknowledgement information

Methods and apparatus are provided for a base station to enable a user equipment (UE) configured for operation with carrier aggregation over a number of cells to determine cells and transmission time intervals (TTIs) where the base station transmits data information to the UE and for the UE to determine and arrange corresponding acknowledgement information in a codeword.

TECHNICAL FIELD

The present application relates generally to wireless communications and, more specifically, to determining a codeword of acknowledgement information in carrier aggregation operation.

BACKGROUND

Wireless communication has been one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeded five billion and continues to grow quickly. The demand of wireless data traffic is rapidly increasing due to the growing popularity among consumers and businesses of smart phones and other mobile data devices, such as tablets, “note pad” computers, net books, eBook readers, and machine type of devices. In order to meet the high growth in mobile data traffic and support new applications and deployments, improvements in radio interface efficiency and coverage is of paramount importance.

SUMMARY

This disclosure provides methods and apparatus for determining a codeword of acknowledgement information in carrier aggregation operation.

In a first embodiment, a method includes receiving control signaling that conveys downlink control information (DCI) formats. Each of the DCI formats indicates scheduling for either a reception for a physical downlink shared channel (PDSCH) or a release for a semi-persistently scheduled (SPS) PDSCH in a transmission time interval (TTI) from a number of TTIs and on a cell from a number of cells. Each TTI has a TTI index and each cell has a cell index. Each of the DCI formats is associated with a cell index and with a TTI index for a respective PDSCH reception or SPS PDSCH release. Each of the DCI formats, when received in a first search space, includes a value for a counter downlink assignment indicator (DAI) field that counts DCI formats, first across cells from the number of cells according to an ascending cell index and then across TTIs from the number of TTIs according to an ascending TTI index, until the index of the TTI and the index of the cell associated with the DCI format. Each of the DCI formats, when received in a second search space, includes a value for a total DAI field that counts DCI formats across all cells and across TTIs from the number of TTIs according to an ascending TTI index until the index of the TTI associated with the DCI format. The method additionally includes generating acknowledgement information bits in response to receiving the PDSCHs or the SPS PDSCH release. The method also includes transmitting the acknowledgement information bits.

In a second embodiment, a UE includes a receiver, a controller, and a transmitter. The receiver is configured to receive control signaling that conveys DCI formats. Each of the DCI formats indicates scheduling for either a reception for a PDSCH or a release for a SPS PDSCH in a TTI from a number of TTIs and on a cell from a number of cells. Each TTI has a TTI index and each cell has a cell index. Each of the DCI formats is associated with a cell index and with a TTI index for a respective PDSCH reception or SPS PDSCH release. Each of the DCI formats, when received in a first search space, includes a value for a counter DAI field that counts DCI formats, first across cells from the number of cells according to an ascending cell index and then across TTIs from the number of TTIs according to an ascending TTI index, until the index of the TTI and the index of the cell associated with the DCI format. Each DCI format, when received in a second search space, includes a value for a total DAI field that counts DCI formats across all cells and across TTIs from the number of TTIs according to an ascending TTI index until the index of the TTI associated with the DCI format. The controller is configured to generate acknowledgement information bits in response to the reception of the PDSCHs or the SPS PDSCH release. The transmitter is configured to transmit the acknowledgement information bits.

In a third embodiment, a base station includes a transmitter and a receiver. The transmitter is configured to transmit control signaling that conveys DCI formats. Each of the DCI format indicates scheduling for either a transmission for a PDSCH or a release for a SPS PDSCH in a TTI from a number of TTIs and on a cell from a number of cells. Each TTI has a TTI index and each cell has a cell index. Each of the DCI formats is associated with a cell index and with a TTI index for a respective PDSCH transmission or SPS PDSCH release. Each of the DCI formats, when transmitted in a first search space, includes a value for a counter DAI field that counts DCI formats, first across cells from the number of cells according to an ascending cell index and then across TTIs from the number of TTIs according to an ascending TTI index, until the index of the TTI and the index of the cell associated with the DCI format. Each of the DCI formats, when transmitted in a second search space, includes a value for a total DAI field that counts DCI formats across all cells and across TTIs from the number of TTIs according to an ascending TTI index until the index of the TTI associated with the DCI format. The receiver is configured to receive acknowledgement information bits in response to the transmission of the PDSCHs or of the SPS PDSCH release.

DETAILED DESCRIPTION

The following documents and standards descriptions are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 36.211 v12.4.0, “E-UTRA, Physical channels and modulation” (REF 1); 3GPP TS 36.212 v12.3.0, “E-UTRA, Multiplexing and Channel coding” (REF 2); 3GPP TS 36.213 v12.4.0, “E-UTRA, Physical Layer Procedures” (REF 3); 3GPP TS 36.331 v12.4.0, “E-UTRA. Radio Resource Control (RRC) Protocol Specification” (REF 4); U.S. Pat. No. 8,588,259, entitled “Multiplexing Large Payloads of Control Information from User Equipments” (REF 5); and U.S. Pat. No. 8,837,450, entitled “Transmission of HARQ Control Information from a User Equipment for Downlink Carrier Aggregation” (REF 6).

One or more embodiments of the present disclosure relate to determining a codeword of acknowledgement information in carrier aggregation (CA) operation. A wireless communication network includes a downlink (DL) that conveys signals from transmission points, such as base stations or enhanced NodeBs (eNBs), to UEs. The wireless communication network also includes an uplink (UL) that conveys signals from UEs to reception points, such as eNBs.

FIG. 1illustrates an example wireless network100according to this disclosure. The embodiment of the wireless network100shown inFIG. 1is for illustration only. Other embodiments of the wireless network100could be used without departing from the scope of this disclosure.

As shown inFIG. 1, the wireless network100includes an eNB101, an eNB102, and an eNB103. The eNB101communicates with the eNB102and the eNB103. The eNB101also communicates with at least one Internet Protocol (IP) network130, such as the Internet, a proprietary IP network, or other data network.

Depending on the network type, other well-known terms may be used instead of “eNodeB” or “eNB,” such as “base station” or “access point.” For the sake of convenience, the terms “eNodeB” and “eNB” are used in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, other well-known terms may be used instead of “user equipment” or “UE,” such as “mobile station,” “subscriber station,” “remote terminal,” “wireless terminal,” or “user device.” A UE may be fixed or mobile and may be a cellular phone, a personal computer device, and the like. For the sake of convenience, the terms “user equipment” and “UE” are used in this patent document to refer to remote wireless equipment that wirelessly accesses an eNB, whether the UE is a mobile device (such as a mobile telephone or smart-phone) or is normally considered a stationary device (such as a desktop computer or vending machine).

The eNB102provides wireless broadband access to the network130for a first plurality of user equipments (UEs) within a coverage area120of the eNB102. The first plurality of UEs includes a UE111, which may be located in a small business (SB); a UE112, which may be located in an enterprise (E); a UE113, which may be located in a WiFi hotspot (HS); a UE114, which may be located in a first residence (R); a UE115, which may be located in a second residence (R); and a UE114, which may be a mobile device (M) like a cell phone, a wireless laptop, a wireless PDA, or the like. The eNB103provides wireless broadband access to the network130for a second plurality of UEs within a coverage area125of the eNB103. The second plurality of UEs includes the UE115and the UE114. In some embodiments, one or more of the eNBs101-103may communicate with each other and with the UEs111-116using 5G, LTE, LTE-A, WiMAX, or other advanced wireless communication techniques.

Dotted lines show the approximate extents of the coverage areas120and125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with eNBs, such as the coverage areas120and125, may have other shapes, including irregular shapes, depending upon the configuration of the eNBs and variations in the radio environment associated with natural and man-made obstructions.

As described in more detail below, various components of the network100(such as the eNBs101-103and/or the UEs111-116) support the adaptation of communication direction in the network100and support transmission or reception of acknowledgement information in CA operation.

AlthoughFIG. 1illustrates one example of a wireless network100, various changes may be made toFIG. 1. For example, the wireless network100could include any number of eNBs and any number of UEs in any suitable arrangement. Also, the eNB101could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network130. Similarly, each eNB102-103could communicate directly between them or with the network130and provide UEs with direct wireless broadband access to the network130. Further, the eNB101,102, and/or103could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

FIG. 2illustrates an example UE114according to this disclosure. The embodiment of the UE114shown inFIG. 2is for illustration only, and the other UEs inFIG. 1could have the same or similar configuration. However, UEs come in a wide variety of configurations, andFIG. 2does not limit the scope of this disclosure to any particular implementation of a UE.

As shown inFIG. 2, the UE114includes an antenna205, a radio frequency (RF) transceiver210, transmit (TX) processing circuitry215, a microphone220, and receive (RX) processing circuitry225. The UE114also includes a speaker230, a processor240, an input/output (I/O) interface (IF)245, an input250, a display255, and a memory260. The memory260includes an operating system (OS) program261and one or more applications262.

The RF transceiver210receives, from the antenna205, an incoming RF signal transmitted by an eNB or another UE. The RF transceiver210down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent to the RX processing circuitry225, which generates a processed baseband signal by filtering, decoding, and/or digitizing the baseband or IF signal. The RX processing circuitry225transmits the processed baseband signal to the speaker230(such as for voice data) or to the processor240for further processing (such as for web browsing data).

The TX processing circuitry215receives analog or digital voice data from the microphone220or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor240. The TX processing circuitry215encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver210receives the outgoing processed baseband or IF signal from the TX processing circuitry215and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna205.

The processor240can include one or more processors or other processing devices and can execute the OS program261stored in the memory260in order to control the overall operation of the UE114. For example, the processor240could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver210, the RX processing circuitry225, and the TX processing circuitry215in accordance with well-known principles. In some embodiments, the processor240includes at least one microprocessor or microcontroller.

The processor240is also capable of executing other processes and programs resident in the memory260. The processor240can move data into or out of the memory260as required by an executing process. In some embodiments, the processor240is configured to execute the applications262based on the OS program261or in response to signals received from eNBs, other UEs, or an operator. The processor240is also coupled to the I/O interface245, which provides the UE114with the ability to connect to other devices such as laptop computers and handheld computers. The I/O interface245is the communication path between these accessories and the processor240.

The processor240is also coupled to the input250(e.g., touchscreen, keypad, etc.) and the display255. The operator of the UE114can use the input250to enter data into the UE114. The display255may be a liquid crystal display or other display capable of rendering text and/or at least limited graphics, such as from web sites. The display255could also represent a touch-screen.

The memory260is coupled to the processor240. Part of the memory260could include a control or data signaling memory (RAM), and another part of the memory260could include a Flash memory or other read-only memory (ROM).

As described in more detail below, the transmit and receive paths of the UE114(implemented using the RF transceiver210, TX processing circuitry215, and/or RX processing circuitry225) support transmission of acknowledgement information in CA operation.

AlthoughFIG. 2illustrates one example of UE114, various changes may be made toFIG. 2. For example, various components inFIG. 2could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor240could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, whileFIG. 2illustrates the UE114configured as a mobile telephone or smart-phone, UEs could be configured to operate as other types of mobile or stationary devices. In addition, various components inFIG. 2could be replicated, such as when different RF components are used to communicate with the eNBs101-103and with other UEs.

FIG. 3illustrates an example eNB102according to this disclosure. The embodiment of the eNB102shown inFIG. 3is for illustration only, and other eNBs ofFIG. 1could have the same or similar configuration. However, eNBs come in a wide variety of configurations, andFIG. 3does not limit the scope of this disclosure to any particular implementation of an eNB.

As shown inFIG. 3, the eNB102includes multiple antennas305a-305n, multiple RF transceivers310a-310n, transmit (TX) processing circuitry315, and receive (RX) processing circuitry320. The eNB102also includes a controller/processor325, a memory330, and a backhaul or network interface335.

The RF transceivers310a-310nreceive, from the antennas305a-305n, incoming RF signals, such as signals transmitted by UEs or other eNBs. The RF transceivers310a-310ndown-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are sent to the RX processing circuitry320, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The RX processing circuitry320transmits the processed baseband signals to the controller/processor325for further processing.

The TX processing circuitry315receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor325. The TX processing circuitry315encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers310a-310nreceive the outgoing processed baseband or IF signals from the TX processing circuitry315and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas305a-305n.

The controller/processor325can include one or more processors or other processing devices that control the overall operation of the eNB102. For example, the controller/processor325could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers310a-310n, the RX processing circuitry320, and the TX processing circuitry315in accordance with well-known principles. The controller/processor325could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor325could support beam forming or directional routing operations in which outgoing signals from multiple antennas305a-305nare weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the eNB102by the controller/processor325. In some embodiments, the controller/processor325includes at least one microprocessor or microcontroller.

The controller/processor325is also capable of executing programs and other processes resident in the memory330, such as an OS. The controller/processor325can move data into or out of the memory330as required by an executing process.

The controller/processor325is also coupled to the backhaul or network interface335. The backhaul or network interface335allows the eNB102to communicate with other devices or systems over a backhaul connection or over a network. The interface335could support communications over any suitable wired or wireless connection(s). For example, when the eNB102is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A), the interface335could allow the eNB102to communicate with other eNBs, such as eNB103, over a wired or wireless backhaul connection. When the eNB102is implemented as an access point, the interface335could allow the eNB102to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface335includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver.

The memory330is coupled to the controller/processor325. Part of the memory330could include a RAM, and another part of the memory330could include a Flash memory or other ROM.

As described in more detail below, the transmit and receive paths of the eNB102(implemented using the RF transceivers310a-310n, TX processing circuitry315, and/or RX processing circuitry320) support reception of acknowledgement information in CA operation.

AlthoughFIG. 3illustrates one example of an eNB102, various changes may be made toFIG. 3. For example, the eNB102could include any number of each component shown inFIG. 3. As a particular example, an access point could include a number of interfaces335, and the controller/processor325could support routing functions to route data between different network addresses. As another particular example, while shown as including a single instance of TX processing circuitry315and a single instance of RX processing circuitry320, the eNB102could include multiple instances of each (such as one per RF transceiver).

In some wireless networks, DL signals can include data signals conveying information content, control signals conveying DL control information (DCI), and reference signals (RS) that are also known as pilot signals. An eNB, such as eNB102, can transmit one or more of multiple types of RS, including UE-common RS (CRS), channel state information RS (CSI-RS), and demodulation RS (DMRS). A CRS can be transmitted over a DL system bandwidth (BW) and can be used by a UE, such as UE114, to demodulate data or control signals or to perform measurements. To reduce CRS overhead, eNB102can transmit a CSI-RS with a smaller density in the time domain than a CRS (see also REF 1 and REF 3). UE114can use either a CRS or a CSI-RS to perform measurements and a selection can be based on a transmission mode (TM) UE114is configured by eNB102for physical DL shared channel (PDSCH) reception (see also REF 3). Finally, UE114can use a DMRS to demodulate data or control signals. The eNB102transmits data information to UE114through a PDSCH. The eNB102transmits control information to UE114through a physical DL control channel (PDCCH) or through an enhanced PDCCH (EPDCCH). Unless otherwise explicitly mentioned, only PDCCH will be referred to in the following but the descriptions are also applicable for EPDCCH.

In some wireless networks, UL signals can include data signals conveying information content, control signals conveying UL control information (UCI), and RS. A UE, such as UE114, can transmit data information or UCI through a respective physical UL shared channel (PUSCH) or a physical UL control channel (PUCCH) to an eNB, such as eNB102. The transport channel transferring information from a PUSCH to higher layers is referred to as UL shared channel (UL-SCH). When UE114simultaneously transmits data information and UCI, UE114can multiplex both in a PUSCH or simultaneously transmit data information and possibly some UCI in a PUSCH and transmit some or all UCI in a PUCCH. UCI can include hybrid automatic repeat request acknowledgement (HARQ-ACK) information indicating correct or incorrect detection of data transport blocks (TBs) in respective PDSCHs, scheduling request (SR) information indicating to eNB102whether UE114has data in its buffer, and channel state information (CSI) enabling eNB102to select appropriate parameters for PDSCH or PDCCH transmissions to UE114. HARQ-ACK information can include a positive acknowledgement (ACK) in response to a correct PDCCH or data TB detection, a negative acknowledgement (NACK) in response to incorrect data TB detection, and an absence of PDCCH detection (DTX) that can be implicit or explicit. A DTX can be implicit when UE114does not transmit a HARQ-ACK signal. It is also possible to represent NACK and DTX with a same NACK/DTX state in the HARQ-ACK information (see also REF 3).

UL RS can include DMRS and sounding RS (SRS). UE114transmits a DMRS only in a BW of a respective PUSCH or PUCCH and eNB102can use a DMRS to demodulate information in a PUSCH or PUCCH. UE114transmits a SRS in order to provide eNB102with a UL CSI (see also REF 2 and REF 3). A DMRS is constructed by a constant amplitude zero autocorrelation (CAZAC) sequence such as a Zadoff-Chu (ZC). UE114applies a cyclic shift (CS) and an orthogonal covering code (OCC) to a DMRS transmission in the two slots of a SF.

The eNB102can schedule a PDSCH transmission to UE114either dynamically, by transmitting a DL DCI format in a PDCCH, or semi-statically by RRC signaling. The eNB102can schedule a PUSCH transmission from UE114either dynamically, by transmitting an UL DCI format in a PDCCH, or semi-statically by RRC signaling. DCI formats can also provide other functionalities (see also REF 2). For example, a DCI format 3/3A can be used to convey to a group of UEs respective power control commands for adjusting a respective PUSCH transmission power or a PUCCH transmission power. UE114detects a PDCCH conveying a DCI format through decoding operation in a common search space (CSS), such as for a DCI format 3/3A, or in a UE-specific search space (USS) see also REF 3. For some DCI formats, such as a DCI format 1A, a respective PDCCH can be transmitted either in a CSS or in a USS. An EPDCCH can be transmitted only in a USS (see also REF 3).

A transmission time interval (TTI) for DL signaling or for UL signaling is one subframe (SF). For example, a SF duration can be one millisecond (msec). A unit of 10 SFs, indexed from 0 to 9, is referred to as a system frame. In a time division duplex (TDD) system, a communication direction in some SFs is in the DL, and a communication direction in some other SFs is in the UL.

FIG. 4illustrates an example UL SF structure for PUSCH transmission or PUCCH transmission according to this disclosure. The embodiment of the UL SF structure shown inFIG. 4is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

UL signaling can use Discrete Fourier Transform Spread OFDM (DFT-S-OFDM). An UL SF410includes two slots. Each slot420includes NsymbULsymbols430where UE114transmits data information, UCI, or RS including one symbol per slot where UE114transmits DMRS440. A transmission BW includes frequency resource units that are referred to as resource blocks (RBs). Each RB includes NscRB(virtual) sub-carriers that are referred to as resource elements (REs). A transmission unit of one RB over one slot is referred to as a physical RB (PRB) and transmission unit of one RB over one SF is referred to as a PRB pair. UE114is assigned MPUXCHRBs for a total of MscPUXCH=MPUXCH·NscRBREs450for a PUSCH transmission BW (‘X’=‘S’) or for a PUCCH transmission BW (‘X’=‘C’). A last SF symbol can be used to multiplex SRS transmissions460from one or more UEs. A number of UL SF symbols available for data/UCI/DMRS transmission is NsymbPUXCH=2·(NsymbUL−1)·NSRS·NSRS=1 when a last SF symbol supports SRS transmissions from UEs that overlap at least partially in BW with a PUXCH transmission BW; otherwise, NSRS=0. Therefore, a number of total REs for a PUXCH transmission is MscPUXCH·NsymbPUXCH.

When the structure inFIG. 4is used to transmit UCI (HARQ-ACK or P-CSI with or without SR) in a PUCCH, there is no data information included and UCI can be mapped over all REs except for REs used to transmit DMRS or SRS.

FIG. 5illustrates an example encoding and modulation process for UCI according to this disclosure. The embodiment of the encoding process shown inFIG. 5is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

Upon determining that a number OUCI,0of UCI bits is larger than a predetermined value, a UE114controller (not shown) provides the UCI bits510to a cyclic redundancy check (CRC) generator520that computes a CRC for the OUCI,0UCI bits and appends OCRCCRC bits, such as 8 CRC bits, to the OUCI,0UCI bits to result OUCIUCI and CRC bits530. An encoder540, such as a tail biting convolutional code (TBCC), encodes the output of OUCIbits. A rate matcher550performs rate matching to allocated resources, followed by a scrambler560to perform scrambling, a modulator570to modulate the encoded bits, for example using QPSK, an RE mapper580, and finally a transmitter for a transmission of a control signal590.

FIG. 6illustrates an example demodulation and decoding process for UCI according to this disclosure. The embodiment of the decoding process shown inFIG. 6is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

The eNB102receives a control signal610that is provided to a RE demapper620to perform RE demapping, a demodulator630to perform demodulation for a corresponding modulation scheme, a descrambler640to perform descrambling, a rate matcher650to perform rate matching, and a decoder660, such as a TBCC decoder, to perform decoding and provide OUCIUCI and CRC bits. A CRC extraction unit670separates OUCI,0UCI bits680and OCRCCRC bits685, and a CRC checking unit690computes a CRC check (whether a CRC checksum is zero for a positive CRC check or non-zero for a negative CRC check). When the CRC check passes (CRC checksum is zero), eNB102determines that the UCI is valid.

The eNB102can use a same transmitter structure for transmitting a DCI format as UE114can use for transmitting UCI inFIG. 5. With respect toFIG. 5, UCI can be replaced by DCI format and a UE-specific scrambler can be replaced by a cell-specific scrambler. Similar, UE114can use a same receiver structure for receiving a DCI format as eNB102can use for receiving UCI inFIG. 6. With respect toFIG. 6, UCI can be replaced by DCI format and a UE-specific descrambler can be replaced by a cell-specific descrambler. Respective descriptions of an eNB102transmitter structure and of a UE114receiver structure for a DCI format are omitted for brevity.

FIG. 7illustrates an example UE transmitter for a PUCCH having a same SF structure as a PUSCH according to this disclosure. The embodiment of the transmitter shown inFIG. 7is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

UCI bits from UE114, such as OP-CSIP-CSI information bits705, when any, and OHARQ-ACKHARQ-ACK information bits710, when any, but also a SR bit in a SF configured to UE114for SR transmission (not shown), are jointly encoded by encoder720. The encoder can be a TBCC or turbo coding (TC) and CRC bits are included in each encoded codeword (see also REF 2). Encoded bits are subsequently modulated by modulator730. A discrete Fourier transform (DFT) is obtained by DFT unit740, REs750corresponding to a PUCCH transmission BW are selected by selector755, an inverse fast Fourier transform (IFFT) is performed by IFFT unit760, an output is filtered and by filter770, a processor applies a power according to a power control procedure to power amplifier (PA)780, and a transmitted790transmits a signal. Due to the DFT mapping, the REs can be viewed as virtual REs but are referred to as REs for simplicity. For brevity, additional transmitter circuitry such as digital-to-analog converter, filters, amplifiers, and transmitter antennas as well as encoders and modulators for data symbols and UCI symbols are omitted.

A UE transmitter block diagram for data in a PUSCH can be obtained as inFIG. 7by replacing HARQ-ACK information and CSI with data information.

FIG. 8illustrates an example eNB receiver for a PUCCH having a same SF structure as a PUSCH according to this disclosure. The embodiment of the receiver shown inFIG. 8is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

A received signal810is filtered by filter820, a fast Fourier transform (FFT) is applied by FFT unit830, a selector unit840selects REs850used by a transmitter, an inverse DFT (IDFT) unit applies an IDFT860, a demodulator870demodulates the IDFT output using a channel estimate provided by a channel estimator (not shown), and finally a decoder880outputs OHARQ-ACKHARQ-ACK information bits890, when any, and OP-CSICSI information bits895, when any, and a SR bit (not shown), when any. Additional receiver circuitry such as a channel estimator, demodulators and decoders for data and UCI symbols are not shown for brevity.

An eNB receiver block diagram for data in a PUSCH can be obtained as inFIG. 8by replacing HARQ-ACK information and CSI with data information.

For transmission of HARQ-ACK information payloads up to 22 bits, or for joint transmission of HARQ-ACK information and single-cell CSI with total payload up to 22 bits, a PUCCH format 3 (see also REF 1 and REF 3) can be used and a payload of OHARQ-ACKHARQ-ACK bits, or a payload of OHARQ-ACKHARQ-ACK bits and OCSICSI bits, can be encoded using a block code. Considering for brevity in the following only the case of HARQ-ACK bits, the block code can be a (32, OHARQ-ACK) Reed-Mueller (RM) code.

FIG. 9illustrates a structure for a PUCCH format 3 over one SF slot for transmission of HARQ-ACK information according to this disclosure.

After encoding and modulation using respectively, for example, a (32, OHARQ-ACK) RM code punctured to a (24, OHARQ-ACK) RM code (see also REF 2) and QPSK) modulation (not shown for brevity), a set of same HARQ-ACK bits910is multiplied920with elements of an OCC930and is subsequently precoded by a DFT filter940. For example, for 5 symbols per slot used to transmit HARQ-ACK bits, the OCC has length 5 {OCC(0), OCC(1), OCC(2), OCC(3), OCC(4)} and can be either of {1, 1, 1, 1, 1}, or {1, exp(j2π/5), exp(j4π/5), exp(j6π/5), exp(j8π/5)}, or {1, exp(j4π/5), exp(j8π/5), exp(j2π/5), exp(j6π/5)}, or {1, exp(j6π/5), exp(j2π/5), exp(j8π/5), exp(j4π/5)}, or {1, exp(j8π/5), exp(j6π/5), exp(j4π/5), exp(j2π/5)}. The output is passed through an IFFT950and then mapped to a SF symbol960. The previous operations are linear and their relative order can be inter-changed. As PUCCH format 3 is transmitted over one PRB pair, 24 encoded HARQ-ACK bits are transmitted in each slot and they are mapped to 12 QPSK symbols in respective 12 REs. Same or different HARQ-ACK bits can be transmitted in the second slot of a SF. RS is also transmitted in each slot to enable coherent demodulation of HARQ-ACK signals. A RS is constructed from a length-12 CAZAC sequence (see also REF 1) 970 that is passed through an IFFT filter980and mapped to another SF symbol990. Multiplexing of RS from different UEs is achieved by using different CS of a same ZC sequence.

The structure inFIG. 9can support a limited payload of HARQ-ACK information bits without incurring a large coding rate. For a HARQ-ACK payload between 12 and 22 bits, a dual RM code can be used where a mapping to successive elements of a DFT can alternate between elements from an output of a first RM code and elements from an output of a second RM code in a sequential manner (not shown for brevity see also REF 2).

FIG. 10illustrates a UE transmitter block diagram for HARQ-ACK information using a PUCCH format 3 according to this disclosure. The embodiment of the transmitter shown inFIG. 10is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

HARQ-ACK information bits1005are encoded and modulated1010and then multiplied1020with an OCC element1025for a respective DFT-S-OFDM symbol. After DFT precoding by filter1030, REs1040of an assigned PRB pair are selected1050, an IFFT is performed1060and finally filtering1070is applied and a signal is transmitted1080. For brevity, additional transmitter circuitry such as RS transmission, CP insertion, digital-to-analog converter, analog filters, amplifiers, and transmitter antennas are not shown.

FIG. 11illustrates an eNB receiver block diagram for receiving HARQ-ACK information in a PUCCH format 3 according to this disclosure. The embodiment of the receiver shown inFIG. 11is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

A received signal1110is filtered by filter1120, followed by FFT filter1130, RE selector1140selects REs1150, filter1160applies an IDFT, multiplier1170multiplies an OCC element1175for a respective PUCCH format 3 SF symbol, summer1180sums the outputs for PUCCH format 3 SF symbols conveying HARQ-ACK signals over each slot, and demodulator and decoder1190demodulate and decode, respectively the HARQ-ACK symbols to obtain HARQ-ACK information bits1195. Well known receiver functionalities such as analog filtering, CP extraction, and RS reception and channel estimation are not shown for brevity.

When UE114transmits OHARQ-ACKHARQ-ACK information in a PUSCH that conveys one data TB, UE114determines a number of coded modulation symbols per layer Q′ for HARQ-ACK as being inversely proportional to a modulation and coding scheme (MCS) for data transmission, or when a modulation for HARQ-ACK information is fixed to QPSK, to a number of coded data symbols as in Equation 1 (see also REF 2)

In a TDD communication system, a communication direction in some SFs is in the DL, and a communication direction in some other SFs is in the UL. Table 1 lists indicative UL/DL configurations over a period of 10 SFs that is also referred to as frame period. “D” denotes a DL SF, “U” denotes an UL SF, and “S” denotes a special SF that includes a DL transmission field referred to as DwPTS, a guard period (GP), and a UL transmission field referred to as UpPTS. Several combinations exist for a duration of each field in a special SF subject to the condition that the total duration is one SF (see also REF 1).

In a TDD system, a HARQ-ACK signal transmission from UE114in response to PDSCH receptions in multiple DL SFs can be transmitted in a same UL SF. A number MWof DL SFs having associated HARQ-ACK signal transmissions from UE114in a same UL SF is referred to as a DL association set or as a bundling window of size MW. A DL DCI format scheduling a PDSCH transmission (or an SPS PDSCH release) includes a DL assignment index (DAI) field of two binary elements (bits) that provides a counter indicating a number of DL DCI formats, modulo 4, transmitted to UE114in a bundling window up to the SF of the DL DCI format detection (see also REF 2 and REF 3). Table 2 indicates DL SFs n−k, where kεK, that UE114transmits an associated HARQ-ACK signal in UL SF n. These DL SFs represent a bundling window for a respective UL SF.

A DAI field having a value VDAIDLis included in each DL DCI format scheduling a PDSCH transmission to UE114. As eNB102cannot predict whether or not eNB102will schedule a PDSCH transmission to UE114in a future SF, VDAIDLis a relative counter that is incremented in DL DCI formats scheduling PDSCH transmissions to UE114in respective SFs of a bundling window. Then, for a DAI field that includes 2 bits, when UE114fails to detect up to 3 successive DL DCI formats scheduling PDSCH transmissions in respective SFs of a bundling window but UE114detects a DL DCI format scheduling a PDSCH transmission in a later SF of the bundling window, UE114can determine that UE114failed to detect the up to 3 successive DL DCI formats and UE114can provide a NACK/DTX indication for HARQ-ACK information for the up to 3 respective PDSCH transmissions. However, since VDAIDLcan only be a relative counter, when UE114fails to detect a DL DCI format scheduling a PDSCH transmission in a last SF within a bundling window, UE114has no means to identify the missed detection. This shortcoming can be circumvented by UE114providing HARQ-ACK information to eNB102regarding outcomes of PDSCH receptions for all SFs of a bundling window (see also REF 3).

One mechanism towards satisfying a demand for increased network capacity and data rates is network densification. This is realized by deploying small cells in order to increase a number of network nodes and their proximity to UEs and provide cell splitting gains. As a number of small cells increases and deployments of small cells become dense, a handover frequency and a handover failure rate can also significantly increase. By maintaining a RRC connection to the macro-cell, communication with the small cell can be optimized as control-place (C-place) functionalities such as mobility management, paging, and system information updates can be provided only by the macro-cell while a small-cell can be dedicated for user-data plane (U-plane) communications. When a latency of a backhaul link between network nodes (cells) is practically zero, CA can be used as in REF 3 and scheduling decisions can be made by a same eNB102and conveyed to each network node. Moreover, UCI from UE114can be received at any network node, except possibly for nodes using unlicensed spectrum, and conveyed to eNB102to facilitate a proper scheduling decision for UE114.

FIG. 12illustrates a communication using CA according to this disclosure.

UE1141210, communicates with a first cell1220corresponding to a macro-cell using a first carrier frequency f11230and with a second cell1240corresponding to a small cell over carrier frequency f21250. The first carrier frequency can correspond to a licensed frequency band and the second carrier frequency can correspond to an unlicensed frequency bad. The first cell and the second cell are controlled by eNB102and are connected over a backhaul that introduces negligible latency.

When UE114is configured with CA operation over a first number of DL cells and over a second number of UL cells, PDCCH transmissions in a CSS are only on a primary DL cell and PUCCH transmissions are only on a primary UL cell that is associated with the primary DL cell. Remaining, DL or UL, cells are referred to as secondary cells (see also REF 3). The eNB102configures UE114with indexes for respective secondary cells while the primary cell has index 0 (see also REF 5). The above functionalities can be parallelized for two cell groups (see also REF 3).

When UE114is configured with CA operation with up to 5 DL cells, HARQ-ACK transmission on a PUCCH typically uses a PUCCH format 3 (see also REF 1 and REF 3). For a TDD system, a PUCCH format 3 resource is determined from a transmission power control (TPC) command field in a DL DCI format with DAI value greater than ‘1’ or with DAI value equal to ‘1’ that is not the first DL DCI format that UE114detects within a bundling window. UE114assumes that a same PUCCH resource index value is transmitted in all DL DCI formats used to determine the PUCCH resource index value for a bundling window (see also REF 3). A functionality of a TPC command field in a DL DCI format with DAI value equal to ‘1’ that is the first DL DCI format UE114detects in a bundling window remains unchanged and provides a TPC command value for UE114to adjust a transmission power for the PUCCH format 3. In this manner, a DAI field functions both as a counter of DL DCI formats transmitted to UE114within a bundling window and as an indicator whether a TPC command field in a DL DCI format provides either a TPC command value or an indicator to one PUCCH resource from a set of PUCCH resources configured to UE114(ARI).

When a DL DCI format is conveyed by an EPDCCH, the DL DCI format also includes a HARQ-ACK resource offset (HRO) field that either indicates a PUCCH resource for a PUCCH format 1a/1b transmission when the DL DCI format schedules PDSCH on a primary cell or is set to zero when the DL DCI format schedules PDSCH on a secondary cell (see also REF 2 and REF 3). Therefore, regardless of whether a DL DCI format scheduling a PDSCH transmission is conveyed by a PDCCH or an EPDCCH, UE114cannot obtain a TPC command to transmit associated HARQ-ACK information in a PUCCH when UE114does not detect a DL DCI format scheduling a PDSCH transmission on a primary cell.

Typical CA operation supports up to 5 DL cells each with a maximum of 20 MHz BW and, for UL/DL configuration 5 in TDD systems, for up to 2 DL cells (see also REF 3). This limitation on the number of DL cells that UE114can support limits DL data rates due to a respective limitation in a total DL BW. With an availability of unlicensed spectrum where many 20 MHz BW carriers can exist, a number of cells that can be configured to UE114can become significantly larger than 5. Therefore, extending support for CA beyond 5 DL cells can allow for more efficient utilization of available spectrum and improve DL data rates and service experience for UE114. A consequence from increasing a number of DL cells relates to a need to support larger UCI payloads. A new PUCCH format that can accommodate large HARQ-ACK payloads or, in general, large UCI payloads can have a PUSCH-based structure (see also REF 5) and use TBCC or TC to encode UCI.

As accommodating large HARQ-ACK payloads requires more UL resources or higher transmission power, thereby increasing an associated overhead, or interference and UE power consumption, it is beneficial for a UE to be provided a capability to dynamically determine a HARQ-ACK payload, and accordingly select a PUCCH format or resources according to a predetermined association with the UCI payload instead of semi-statically determine the HARQ-ACK payload based on a number of configured DL cells and a configured PDSCH TM per each configured DL cell (see also REF 2 and REF 3). This can also be beneficial for reducing a resource overhead required for multiplexing HARQ-ACK in a PUSCH.

Embodiments of this disclosure provide mechanisms for a UE to determine a HARQ-ACK codeword. Embodiments of this disclosure also provide mechanisms for a UE to select a PUCCH format or PUCCH resources according to a predetermined association with a HARQ-ACK codeword size. Embodiments of this disclosure additionally provide mechanisms for introducing and utilizing DAI fields to determine and arrange HARQ-ACK information bits in a codeword for transmission in a PUCCH or in a PUSCH. Embodiments of this disclosure further provide mechanisms for an eNB to resolve possible error cases when a UE determines a HARQ-ACK codeword.

When eNB102configures a parameters to UE114, unless otherwise explicitly mentioned, the configuration is by higher layer signaling, such as RRC signaling. When eNB102dynamically indicates a parameter to UE114, the indication is by physical layer signaling such as by a DCI format.

In the following, for brevity and with a few exceptions, a SPS PDSCH transmission or a DL DCI format indicating SPS PDSCH release is not explicitly mentioned; UE114is assumed to include HARQ-ACK information for SPS PDSCH transmission or for a DL DCI format indicating SPS PDSCH release (see also REF 3). A DCI format indicating SPS PDSCH release includes a same set of DAI fields as a DCI format scheduling a PDSCH transmission. A DL DCI format refers to a DCI format scheduling a PDSCH transmission or a SPS PDSCH release and an UL DCI format refers to a DCI format scheduling a PUSCH transmission.

UE114is configured a group of cells for possible receptions of respective PDSCH transmissions (DL cells) for operation with CA. Each cell in the group of cells is identified by a UE-specific cell index that eNB102informs to UE114through higher layer signaling. For example, UE114can be configured with a group of C cells and respective cell indexes 0, 1, . . . , C−1. UE114generates one HARQ-ACK information bit in response to one DL DCI format detection when UE114is configured with HARQ-ACK spatial domain bundling or, for each cell from the group of C cells, with a PDSCH TM that enables transmission of only one data TB. UE114generates two HARQ-ACK information bits in response to a DL DCI format detection when UE114is not configured with spatial domain bundling and UE114is configured with a PDSCH TM that enables transmission of two data TB in at least one cell from the C cells. For brevity, unless explicitly mentioned, following descriptions consider that UE114generates one HARQ-ACK information bit in response to one DL DCI format detection.

The eNB102can also configure UE114with more than one cell for PUCCH transmission (UL cell), such as for example two UL cells. PUCCH transmission in a first UL cell is associated with a first group of DL cells and PUCCH transmission in a second UL cell is associated with a second group of DL cells. UE114transmits a PUCCH on a primary cell of a DL cell group. Unless otherwise explicitly noted, the descriptions in this disclosure are with respect to one group of DL cells and can be replicated per group of DL cells in case of more than one group of DL cells.

Selection of PUCCH Format or of PUCCH Resources for HARQ-ACK Transmission

UE114can select a PUCCH format or determine resources for a PUCCH format transmission based on an actual HARQ-ACK payload instead of a maximum HARQ-ACK payload that is determined from a number of cells that UE114is configured by eNB102and a configured PDSCH TM in each of the configured cells (see also REF 2 and REF 3).

UE114can use a first PUCCH format, such as PUCCH Format 3, to transmit up to a first number of HARQ-ACK information bits, such as 22 bits, and use a second PUCCH format, such as one based on a PUSCH structure, to transmit a number of HARQ-ACK information bits larger than the first number.

FIG. 13illustrates a selection by a UE of a PUCCH format based on an associated HARQ-ACK codeword size according to this disclosure.

UE114is configured for CA operation and determines a HARQ-ACK information payload1310. As subsequently described, a determination can be based on one or more DAI fields in respective one or more DL DCI formats scheduling respective one or more PDSCH transmissions (including an SPS PDSCH release) to UE114in respective one or more cells from a group of cells and, for a TDD system, in one or more SFs of a bundling window. UE114examines whether the HARQ-ACK payload is larger than a threshold1320. The threshold can be predetermined in a system operation, such as 11 bits or 22 bits, or can be configured to UE114by eNB102. When the HARQ-ACK payload is not larger than the threshold, UE114transmits the HARQ-ACK payload using a first PUCCH format1330, such as PUCCH format 3. When the HARQ-ACK payload is larger than the threshold, UE114transmits the HARQ-ACK payload using a second PUCCH format1340such as one having the PUSCH SF structure (see also REF 5).

DAI Design for a FDD System

For a FDD system, UE114can determine a HARQ-ACK payload (HARQ-ACK codeword size) to transmit in a PUCCH based on a cell-domain DAI in DL DCI formats scheduling PDSCH transmissions or SPS PDSCH release in respective cells that UE114detects, and on SPS PDSCH transmissions to UE114, when any, in a same SF.

In a first approach, a value VDAIDL-Cof a cell-domain DAI field in a DL DCI format can be a relative counter for a cell where UE114is scheduled a PDSCH transmission where the relative counter increments according to an ascending order of a cell index. For example, when UE114is configured with 32 cells for PDSCH transmissions, a DAI of 5 bits in a DL DCI format can provide an index of a respective cell where UE114is scheduled PDSCH transmission in a SF.

When UE114is configured for potential PDSCH transmissions in C cells, a cell-domain DAI size can be ┌log2C┐ bits. Alternatively, to have a same DL DCI format size regardless of a number of cells that UE114is configured PDSCH transmissions, a DAI size can be ┌log2Cmax┐ bits where Cmaxis a maximum number of cells in a system operation, such as 32 cells. When UE114is configured to receive PDSCH in C<Cmaxcells, UE114can assume that a DL DCI format is not valid when the DL DCI format conveys a DAI value larger than C or UE114can assume that bits of a DAI field for DAI values corresponding to cell indexes larger than C are set to zero. For example, when UE114is configured to receive PDSCH in c≦16 cells and Cmax=32, UE114can assume that a most significant bit (MSB) of the DAI is set to 0.

Although a DAI design according to the first approach can indicate a relative order of cells where UE114is scheduled PDSCH transmissions in a SF, the first approach requires a relatively large number of bits and UE114cannot determine whether UE114failed to detect DL DCI formats scheduling PDSCH transmissions in cells with indexes larger than a largest index of a cell that UE114detected a DL DCI format scheduling a PDSCH transmission.

In a second approach, to avoid having a large number of bits to represent a cell-domain DAI, a DAI value VDAIDL-Ccan still be a relative counter according to a cell index for a transmitted DL DCI format but also rely on a sufficiently low probability that UE114fails to detect a number of DL DCI formats scheduling respective PDSCH transmissions in cells indicated by successive values VDAIDL-C. Assuming that UE114detects a DL DCI format that schedules a PDSCH transmission to UE114in a cell with index c and includes a DAI field with a first value VDAI,1DL-C, and that UE114detects a DL DCI format that schedules a PDSCH transmission to UE114in a cell with index c+j and includes a DAI field with a second value VDAI,2DL-C=VDAI,1DL-C+1, and UE114does not detect a DL DCI format scheduling a PDSCH transmission to UE114in cells with indexes between c and c+j, UE114can assume that there is no PDSCH transmission to UE114in any cell with index between c and c+j. In order to avoid any adverse effects on operation, a probability of the above assumption to be incorrect should be much smaller than a probability of incorrect HARQ-ACK detection at eNB102. For example, assuming a probability of 1 e-2 that UE114fails to detect a DL DCI format, that this probability is independent for different DL DCI formats, and a probability of 1e-4 for incorrect HARQ-ACK detection at eNB102, a probability that UE114fails to detect 4 DL DCI formats for cells with indexes between c and c+j is 1e-8 (when j≧4) and this probability is sufficiently smaller than the probability of 1e-4 for incorrect HARQ-ACK detection at eNB102. Then, a cell-domain DAI field of 2 bits suffices and mapping can be as in Table 3.

TABLE 3Value of Cell-Domain Relative Counter DAIDAINumber of DL Cells with PDSCHMSB,transmission and with PDCCH/EPDCCHLSBVDAIDL-Cindicating DL SPS release0, 011 or 5 or 9 or 13 or 17 or 21 or 25 or 290, 122 or 6 or 10 or 14 or 18 or 22 or 26 or 301, 033 or 7 or 11 or 15 or 19 or 23 or 27 or 311, 140 or 4 or 8 or 12 or 16 or 20 or 24 or 28 or 32

For example, when UE114detects a DL DCI format having a cell-domain relative counter DAI field with value VDAIDL-C=2 and scheduling PDSCH transmission in cell c and UE114detects a DL DCI format having a cell-domain DAI field value VDAIDL-C=1 and scheduling PDSCH transmission in cell c+j, where j>2, UE114can determine that UE114missed detecting two DL DCI formats scheduling respective PDSCH transmissions in cells with indexes between c and c+j. For example, when UE114detects a DL DCI format having a cell-domain relative counter DAI field with value VDAIDL-C=2 and scheduling a PDSCH transmission in cell c and detects a DL DCI format having a cell-domain relative counter DAI field with value VDAIDL-C=3 and scheduling a PDSCH transmission in cell c+j where j>0, UE114can determine that there was no DL DCI format scheduling a PDSCH transmission to UE114in cells with indexes between c and c+j. Therefore, for a cell-domain counter DAI field with value VDAIDL-Cmapping as in Table 3, UE114can determine whether UE114failed to detect up to three DL DCI formats scheduling respective PDSCH transmissions (or a SPS PDSCH release) in respective cells with indexes between an index of a first cell and an index of a second cell that UE114detects DL DCI formats scheduling respective PDSCH transmissions.

Regardless of a size of a cell-domain relative counter DAI field, an additional mechanism is needed to solve a problem of UE114not knowing whether UE114failed to detect DL DCI formats for one or more cells with larger indexes than a largest index of a cell that UE114detects a respective DL DCI format scheduling a PDSCH transmission in a same SF. This problem is similar to one for a TDD system where UE114cannot determine whether or not UE114failed to detect DL DCI formats transmitted in SFs of a bundling window that occur after a last SF within the bundling window where UE114detected a DL DCI format. However, unlike a TDD system where eNB102cannot predict future scheduling decisions in order to inform UE114, eNB102knows a number of DL DCI formats that eNB102transmits to UE114in a SF and eNB102can additionally include either a total counter DAI field or a forward counter DAI field in the DL DCI format as is subsequently described.

A value VDAI,FDL-Cof a forward counter DAI field in a DL DCI format can indicate to UE114whether or not there are DL DCI formats scheduling PDSCH transmissions in cells with indexes larger than an index of a cell that the DL DCI format schedules a PDSCH transmission to UE114. For example, the forward counter DAI can include 1 bit to indicate whether or not there is at least one more DL DCI format scheduling a PDSCH transmission in a cell with a larger index, or 2 bits to indicate whether there are 0, 1, 2, or 3 more DL DCI formats scheduling respective PDSCH transmissions in respective cells with larger indexes, and so on. Based on a value of a forward counter DAI in a DL DCI format that UE114detects and schedules a PDSCH transmission for a cell, UE114can determine whether or not UE114failed to detect up to three DL DCI formats that schedule PDSCH transmissions in cells with indexes larger that the index of the cell. A mapping to numeric values of a forward counter DAI that includes 2 bits can be as in Table 4.

TABLE 4Value of Cell-Domain Forward Counter DAIDAINumber of DL cells with PDSCHMSB,transmission and with PDCCH/LSBVDAI,FDL-CEPDCCH indicating DL SPS release0, 011 or 5 or 9 or 13 or 17 or 21 or 25 or 290, 122 or 6 or 10 or 14 or 18 or 22 or 26 or 301, 033 or 7 or 11 or 15 or 19 or 23 or 27 or 311, 140 or 4 or 8 or 12 or 16 or 20 or 24 or 28

FIG. 14illustrates a functionality of a cell-domain DAI that includes a relative counter DAI and a forward counter DAI according to this disclosure.

The eNB102configures UE114for PDSCH transmissions in ten cells of a FDD system. In a SF, eNB102transmits to UE114three DL DCI formats for Cell#21410, Cell#51420, and Cell#71430. A cell-domain DAI in a first DL DCI format for Cell#2includes a relative counter DAI with value VDAIDL-C=1 (binary value ‘00’) and a forward counter DAI with value VDAI,FDL-C=2 (binary value ‘01’), a cell-domain DAI in a second DL DCI format for Cell#5includes a relative counter DAI with value VDAIDL-C=2 (binary value ‘01’) and a forward counter DAI with value VDAI,FDL-C=1 (binary value ‘00’), and a cell-domain DAI in a third DL DCI format for Cell#7includes a relative counter DAI with value VDAIDL-C=3 (binary value ‘10’) and a forward counter DAI with value VDAI,FDL-C=0 (binary value ‘11’). UE114fails to detect the DL DCI format for Cell#5and the DL DCI format for Cell#7. Based on the value of the relative counter DAI and the value of the forward counter DAI in the DL DCI format for Cell#2, UE114can determine that UE114failed to detect two DL DCI formats in cells with indexes larger than the index of Cell#2and UE114places NACK/DTX values for respective HARQ-ACK information bits after the HARQ-ACK information bit for Cell#2.

A value VDAI,TDL-Cof a total counter DAI field in a DL DCI format can indicate to UE114a total number of DL DCI formats scheduling PDSCH transmissions in respective cells in a SF. For a total counter DAI field of 2 bits, a mapping to numeric values VDAI,TDL-Ccan be as in Table 3 with VDAI,TDL-Creplacing VDAIDL-C. Based on a value VDAI,TDL-Cfor the total counter DAI and on a value VDAIDL-Cfor the relative counter DAI in a DL DCI format scheduling a PDSCH transmission to UE114in a cell, UE114can determine a number of DL DCI formats that UE114failed to detect as well as indexes of cells for the number of DL DCI formats relative to the index of the cell.

FIG. 15illustrates a functionality of a cell-domain DAI that includes a relative counter DAI and a total counter DAI according to this disclosure.

UE114is configured by eNB102for PDSCH transmissions in ten cells of a FDD system. In a SF, eNB102transmits to UE114three DL DCI formats for Cell#21510, Cell#51520, and Cell#71530. A cell-domain DAI in a first DL DCI format for Cell#2includes a relative counter DAI with value VDAIDL-C=1 (binary value ‘00’) and a total counter DAI with value VDAI,TDL-C=3 (binary value ‘10’), a cell-domain DAI in a second DL DCI format for Cell#5includes a relative counter DAI with value VDAIDL-C=2 (binary value ‘01’) and a total counter DAI with value VDAI,TDL-C=3 (binary value ‘10’), and a cell-domain DAI in a third DL DCI format for Cell#7includes a relative counter DAI with value VDAIDL-C=3 (binary value ‘10’), and a total counter DAI with value VDAI,TDL-C=3 (binary value ‘10’). UE114fails to detect the DL DCI format for Cell#2and the DL DCI format for Cell#7. Based on the value VDAIDL-C=2 of the relative counter DAI and the value VDAI,TDL-C=3 of the total counter DAI in the DL DCI format for Cell#5, UE114can determine that UE114failed to detect two DL DCI formats, where a first DL DCI format is for a first cell with index smaller than the index of Cell#5and a second DL DCI format is for a second cell with index larger than the index of Cell#5, and UE114places NACK/DTX values for the respective HARQ-ACK information bits.

In addition to UE114determining a number of cells that UE114fails to detect respective DL DCI formats scheduling respective PDSCH transmissions and an order of a number of cells according to respective configured indexes, UE114needs to determine whether UE114needs to convey one or two HARQ-ACK information bits (both with NACK/DTX value) for each cell from the number of cells according to a PDSCH TM in the cell. When UE114applies HARQ-ACK spatial domain bundling, UE114provides HARQ-ACK feedback only for a number of cells that UE114determines as having respective PDSCH transmissions (or SPS PDSCH release) in a SF. This avoids a dependence of HARQ-ACK information that UE114generates on a respective PDSCH TM and results to UE114generating one HARQ-ACK information bit for each cell that UE114identifies as UE114having a scheduled PDSCH transmission in a SF. When UE114does not apply HARQ-ACK spatial domain bundling and UE114is configured for at least one cell a PDSCH TM that supports more than one data TB, UE114reports two HARQ-ACK information bits for all cells to avoid a dependence of HARQ-ACK information that UE114generates on a respective PDSCH TM.

An order of HARQ-ACK information bits in a codeword for transmission using a PUCCH format can be according to an order of indexes of cells that UE114identifies as having a scheduled PDSCH transmission in a respective SF. UE114can place a HARQ-ACK information bit in response to a SPS PDSCH transmission either according to a respective cell index or at a predetermined location in a HARQ-ACK codeword, such as a first one or a last one.

FIG. 16illustrates a generation of HARQ-ACK information bits by a UE based on a counter DAI field and either on a forward DAI field or on a total DAI field according to this disclosure.

UE114is configured for CA operation and detects one or more DL DCI formats that schedule respective one or more PDSCH transmissions in one or more respective cells in a SF. A DL DCI format includes a cell-domain DAI field that comprises of a relative counter DAI and either a forward counter DAI or a total counter DAI1610. Based on values of the two DAIS fields in the one or more DL DCI formats, UE114determines cell indexes with received and non-received PDSCH transmissions1620that correspond to detected or non-detected DL DCI formats. UE114generates HARQ-ACK information for received and non-received PDSCH transmissions. UE114can either apply HARQ-ACK spatial domain bundling in case a PDSCH TM is associated with transmission of two data TBs, or transmit two HARQ-ACK bits per cell when UE114is configured with a PDSCH TM associated with transmission of two data TBs in at least one cell, or transmit one HARQ-ACK bit per cell when UE114is configured with a PDSCH TM associated with transmission of one data TB in all cells1630. UE114arranges the HARQ-ACK information according to cell indexes of received and non-received PDSCH transmissions1640. Finally, UE114encodes, modulates, and transmits the HARQ-ACK information using a PUCCH format1650. UE114can select the PUCCH format based on a HARQ-ACK payload.

DAI Design for a TDD System

For a TDD system, in addition to a cell dimension, HARQ-ACK codeword determination needs to account for a time dimension corresponding to SFs in a bundling window. This is achieved by including in a DL DCI format both a cell-domain DAI that UE114can use to derive a number of DL DCI formats that eNB102transmits to UE114in a respective SF of a bundling window and a time-domain DAI that UE114can use to determine whether or not UE114failed to detect some or all DL DCI formats that eNB102transmitted to UE114in a previous SF of the bundling window or by including a 2-dimensional DAI spanning both the cell-domain and the time-domain (cell/time-domain DAI).

When a DL DCI format transmission is in a same SF as an associated PDSCH transmission (or SPS PDSCH release), there is no difference between a DAI counting DCI format transmissions or PDSCH transmissions. When a DL DCI format transmission is in a first SF and an associated PDSCH transmission (or SPS PDSCH release) is in a second SF and the second SF can occur after the first SF, a DAI value needs to count PDSCH transmissions at least when the first SF and the second SF are not associated by a predetermined and fixed time difference. For example, a DL DCI format can include a time index of 2 bits that can indicate whether a SF of an associated PDSCH transmission is 0, 1, 2, or 3 SFs after a SF of the DL DCI format transmission. Then, for a same cell, a one-to-one mapping between a SF of DCI format transmission and an associated HARQ-ACK information bit is not ensured while a one-to-one mapping between a SF of PDSCH transmission and an associated HARQ-ACK information bit is ensured.

A cell-domain DAI design and functionality can be a relative counter only in a cell domain as for a FDD system, or a relative counter across cells and SFs (cell/time-domain DAI) as subsequently described. A cell/time-domain DAI can be a relative counter DAI mapping first in the cell domain and then in the time domain. A time-domain DAI design and functionality can provide a total number of DL DCI formats that eNB102transmits to UE114in a number of SFs of a bundling window as subsequently described.

Unlike a FDD system where UE114does not transmit HARQ-ACK information when UE114does not detect a DL DCI format in a SF, for a TDD system a result of UE114failing to detect a DL DCI format that eNB102transmits to UE114in a SF of a bundling window after a last SF of the bundling window where UE114detects a DL DCI format, is an incorrect determination of a HARQ-ACK payload (assuming that UE114determines the HARQ-ACK payload based on a number of DL DCI formats the UE114determines that eNB102transmitted in SFs of the bundling window). For example, in a last SF of a bundling window with DL DCI format transmissions to UE114, eNB102can transmit only one DL DCI format to UE114and when UE114fails to detect the one DL DCI format, UE114is not able to accurately determine a HARQ-ACK payload over the bundling window. In this example, the problem can be addressed by a receiver implementation of eNB102to determine whether or not UE114transmits a first HARQ-ACK payload or a second HARQ-ACK payload. The first HARQ-ACK payload can be one corresponding to UE114having a correct determination of transmitted DL DCI formats in a bundling window and the second HARQ-ACK payload can be one corresponding to UE114failing to determine transmitted DL DCI formats in a last SF within a bundling window where eNB102transmits DL DCI formats to UE114.

In a first approach, when UE114transmits a first HARQ-ACK payload using a first PUCCH format or a first PUCCH resource and UE114transmits a second HARQ-ACK payload using a second PUCCH format or a second PUCCH resource, eNB102can determine the PUCCH format or the PUCCH resource that UE114uses to transmit the HARQ-ACK payload by determining a discontinuous transmission (DTX) for the other PUCCH format or the other PUCCH resource. For example, DTX can be determined when a received signal power, such as a RS power, is below a threshold.

In a second approach, for example when UE114can use a same PUCCH format and a same PUCCH to transmit different HARQ-ACK payloads, eNB102can perform decoding operations according to a first HARQ-ACK payload and according to a second HARQ-ACK payload and select a hypothesis resulting to a larger normalized decoding metric such as a larger likelihood metric for a decided codeword according to the first or the second HARQ-ACK payload.

In a third approach, for example when UE114can use a same PUCCH format and a same PUCCH to transmit different HARQ-ACK payloads, UE114can include a CRC in an encoding of a HARQ-ACK information codeword and eNB102can detect a HARQ-ACK codeword according to a set of different possible HARQ-ACK payloads and determine a HARQ-ACK codeword based on a successful CRC check (CRC checksum is zero).

In a fourth approach, when UE114uses a same PUCCH format and a same PUCCH resource to transmit a first HARQ-ACK payload and a second HARQ-ACK payload, UE114can be configured to use different attributes of an associated DMRS according to a last SF within a bundling window where UE114detects a DL DCI format. For example, UE114can use a first CS/OCC for a DMRS transmission when UE114detects a last DL DCI format in a first SF of a bundling window, a second CS/OCC for a DMRS transmission when UE114detects a last DL DCI format in a second SF of a bundling window, and so on. When a number of SFs in a bundling window MWis larger than a number of DMRS CS/OCCs MCS/OCC, UE114can use a first CS/OCC value for SF MCS/OCC+1, and so on.

FIG. 17illustrates a procedure for a UE to transmit and for an eNB to detect an HARQ-ACK information payload according to this disclosure.

UE114encodes and transmits a HARQ-ACK payload in a PUCCH using a PUCCH format in a PUCCH resource1710. The eNB102considers at least two hypotheses for a received HARQ-ACK payload size1720. Each of at least two hypotheses can be associated with a different PUCCH format, or with different resources, or with a same PUCCH format and a same resource. The eNB102determines a metric for each of the at least two hypotheses1730. For example, a metric can be a received power for each of the different PUCCH formats or resources, or a likelihood metric for a decoded HARQ-ACK codeword for each of the at least two hypotheses, or a CRC check result for a decoded HARQ-ACK codeword for each of the at least two hypotheses, or a DMRS received power for each of the at least two hypotheses assuming that each of the at least two hypotheses corresponds to a different CS/OCC for the DMRS. The eNB102decides on one of the at least two hypotheses based at least on a value of the respective metrics1740. The eNB102can further condition a decision depending on a probability for a respective metric. For example eNB102can assign a larger weight to a metric corresponding to UE114detecting at least one DL DCI format from one or more DL DCI formats that eNB102transmits to UE114in a last SF within a bundling window.

An alternative to using a cell-specific functionality for a time-domain DAI is to change the functionality of the time-domain DAI to cell-common (time-domain total counter DAT). When UE114detects a DL DCI format scheduling a PDSCH transmission on a cell in a SF within a bundling window, a cell-domain DAI value VDAIDL-Ccan provide a total number of DL DCI formats transmitted to UE114in the SF of the bundling window while a time-domain DAI value VDAI,TDL-Tcan provide a count of DL DCI formats transmitted in previous SFs of the bundling window, when any, and in the SF. In this manner, UE114can use a value VDAI,TDL-Tof a time-domain total counter DAI field in a DL DCI format to determine a number of DL DCI formats that UE114failed to detect in respective SFs of a bundling window that occur prior to or at the SF where UE114detects the DL DCI format that includes the time-domain total counter DAI field with value VDAI,TDL-T.

A time-domain total counter DAI value VDAI,TDL-Tacts as a counter for all DL DCI formats transmitted to UE114in all SFs (across all cells) up to a SF where eNB102transmits the DL DCI format that includes the time-domain total counter DAI value VDAI,TDL-T. As a consequence, unlike a FDD system, a cell-domain DAI for a TDD system need only include a relative counter VDAIDL-Cof a DL DCI format for a cell according to a cell index. A cell-common functionality of a time-domain total counter DAI value VDAI,TDL-Tdoes not preclude UE114from incorrectly determining a HARQ-ACK payload for transmission in a PUCCH when UE114fails to detect any DL DCI format that eNB102transmits to UE114in a last SF within a bundling window (and therefore means such as ones described with respect toFIG. 17can be additionally needed by eNB102to correctly detect a HARQ-ACK codeword transmitted by UE114). However, a cell-common functionality of a time-domain total counter DAI can result to a correct HARQ-ACK payload determination and arrangement of HARQ-ACK information bits in a codeword (HARQ-ACK codebook determination) for HARQ-ACK transmission in a PUSCH where a DAI field in a DL DCI format scheduling a PUSCH transmission (UL DAI) can serve as time-domain total counter DAI for a last SF in a bundling window where eNB102transmits to UE114DL DCI formats scheduling PDSCH transmissions.

FIG. 18illustrates a combined functionality of a relative counter DAI and of a total counter DAI according to this disclosure.

The eNB102configures UE114ten DL cells for PDSCH transmissions in a TDD system where a bundling window size includes four SFs. In a first SF, SF#01810, eNB102transmits to UE114three DL DCI formats scheduling PDSCH transmissions in Cell#2, Cell#5, and Cell#7, respectively. A cell-domain counter DAI in a DL DCI format for Cell#2has a value VDAIDL-Cof ‘00’ for a counter of the DL DCI format, a cell-domain counter DAI in a DL DCI format for Cell#5has a value VDAIDL-Cof ‘01’ for a counter of the DL DCI format, and a cell-domain counter DAI in a DL DCI format for Cell#7has a value VDAIDL-Cof ‘10’ for a counter of the DL DCI format. In SF#0, a time-domain total counter DAI in each of the three DL DCI formats has a value VDAI,TDL-Tof ‘10’ (corresponds to a numeric value of 3).

In a second SF, SF#11820, eNB102transmits to UE114three DL DCI formats scheduling PDSCH transmissions in Cell#3, Cell#6, and Cell#7. A cell-domain counter DAI in a DL DCI format for Cell#3has a value VDAIDL-Cof ‘00’ for a counter of the DL DCI format, a cell-domain counter DAI in a DL DCI format for Cell#6has a value VDAIDL-Cof ‘01’ for a counter of the DL DCI format, and a cell-domain counter DAI in a DL DCI format for Cell#7has a value VDAIDL-Cof ‘10’ for a counter of the DL DCI format. In SF#1, a time-domain total counter DAI in each of the three DL DCI formats has a value VDAI,TDL-Tof ‘01’ (equivalent to a numeric value of 6).

In a third SF, SF#21830, eNB102transmits to UE114two DL DCI formats scheduling PDSCH transmissions in Cell#5and Cell#7and UE114fails to detect both DL DCI formats. A cell-domain counter DAI in a DL DCI format for Cell#5has a value VDAIDL-Cof ‘00’ for a counter of the DL DCI format and a cell-domain counter DAI in a DL DCI format for Cell#7has a value VDAIDL-Cof ‘01’ for a counter of the DCI format. In SF#2, a time-domain total counter DAI in each of the two DL DCI formats has a value VDAI,TDL-Tof ‘11’ (corresponds to a numeric value of 8).

In a fourth SF, SF#31840, eNB102transmits to UE114three DL DCI formats scheduling PDSCH transmissions in Cell#3, Cell#6, and Cell#7. A cell-domain counter DAI in a DL DCI format for Cell#3has a value VDAIDL-Cof ‘00’ for a counter of the DL DCI format, a cell-domain counter DAI in a DL DCI format for Cell#6has a value VDAIDL-Cof ‘01’ for a counter of the DL DCI format, and a cell-domain counter DAI in a DL DCI format for Cell#7has a value VDAIDL-C‘10’ for a counter of the DL DCI format. In SF#3, a time-domain total counter DAI in each of the three DL DCI formats has a value VDAI,TDL-Tof ‘10’ (corresponds to a numeric value of 11). UE114knows that the time-domain total counter DAI value VDAIDL-CTis a numeric 6 in SF#1and a numeric 11 in SF#3, determines 3 DL DCI formats in SF#3, and therefore UE114knows that UE114failed to detect 2 DL DCI formats in SF#2.

Instead of a time-domain total DAI being a cell-common total counter DAI, a cell/time-domain relative counter DAI can be used. A cell/time-domain relative counter DAI field can be same as an existing DAI field in a DL DCI format for a TDD system but with a different interpretation. For example, for CA operation with up to five DL cells in a TDD system, DL DCI formats include a DAI field of 2 bits that is cell-specific and functions as a relative counter of DL DCI formats in SFs of a bundling window for a cell (see also REF 2 and REF 3). For CA operation with more than 5 DL cells in a TDD system, a DAI field in a DL DCI format scheduling a PDSCH transmission in a SF on a cell provides a counter VDAIDL-CTof DL DCI formats, up to the SF and the cell, first across cells starting from a cell with a smallest index (Cell#0) and then across SFs in a bundling window starting from a SF with a smallest index (SF#0). A configuration for a use of a DAI field in a DL DCI format can be implicit, such as for example when UE114is configured with a number of cells that is larger than a predetermined number, such as 5, or explicit such as by 1-bit indicating either a cell-specific use of a counter DAI field across SFs of a bundling window (as in REF 2 and REF 3) or a 2-dimensional use of the counter DAI field first across cells and then across SFs up to a SF and a cell corresponding to the DL DCI format. For a number of C configured cells and a bundling window size of MWSFs, a joint cell/time-domain relative counter DAI field can include 2 bits and a mapping of VDAIDL-CTcan be as a mapping of VDAIUL-CTin Table 5 (same mapping applies for values VDAI,TDL-Tof a time-domain total counter DAI field of 2 bits).

For brevity, in the following, a cell/time-domain relative counter DAI is referred to as counter DAI and a time-domain total DAI is referred to as total DAI.

FIG. 19illustrates a determination and arrangement for a HARQ-ACK information payload using a counter DAI for a TDD system according to this disclosure.

UE114is configured by eNB102for PDSCH transmissions in ten cells of a TDD system where a bundling window size includes four SFs. In a first SF, SF#01910, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#2, Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=1 for Cell#2, a value VDAIDL-CT=2 for Cell#5, and a value VDAIDL-CT=3 for Cell#7. In a second SF, SF#11920, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#3, Cell#6, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=4 for Cell#3, a value VDAIDL-CT=5 for Cell#6, and a value VDAIDL-CT=6 for Cell#7. In a third SF, SF#21930, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#5and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=7 for Cell#5and a value VDAIDL-CT=8 for Cell#7. In a fourth SF, SF#31940, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#3and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=9 for Cell#3and a value VDAIDL-CT=10 for Cell#7.

In SF#01910, UE114detects the first and third DL DCI formats and fails to detect the second DL DCI format. From the values VDAIDL-CT=1 and VDAIDL-CT=3 of the counter DAI in the two detected DL DCI formats in SF#0, UE114determines that UE114failed to detect a DL DCI format for a cell with index larger than 2 and smaller than 7. Therefore, UE114can determine and arrange the HARQ-ACK information bits as {x, NACK/DTX, x}, where ‘x’ represents either an ACK or a NACK/DTX, in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in SF#0. In SF#11920, UE114detects the first and second DL DCI formats and fails to detect the third DL DCI format. From the values VDAIDL-CT=4 and VDAIDL-CT=5 of the counter DAI in the two detected DL DCI formats in SF#1, UE114determines that UE114did not fail to detect any other DL DCI format in SF#0. For SF#0and SF#1, the UE can generate HARQ-ACK information bits as {x, NACK/DTX, x, x, x}. In SF#21930, UE114detects both the first and second DL DCI formats. From the value VDAIDL-CT=7 of the counter DAI in the detected DL DCI format for Cell#5in SF#2, UE114determines that UE114failed to detect a DL DCI format in SF#1for a cell with larger index than Cell#6. From the value VDAIDL-CT=8 of the counter DAI in the detected DL DCI format for Cell#7in SF#2, UE114determines that UE114did not fail to detect a DL DCI format in SF#2for a cell with smaller index than Cell#7. For SF#0, SF#1, and SF#2, UE114can generate HARQ-ACK information bits as {x, NACK/DTX, x, x, x, NACK/DTX, x, x}. In SF#31940, UE114fails to detect both the first and second DL DCI formats and UE114cannot determine this error event.

The functionalities of a counter DAI (as described inFIG. 19) and of a total counter DAI (as described inFIG. 18) can be combined. A DL DCI format transmitted in a SF for PDSCH transmission in a cell can include a counter DAI providing a counter of DL DCI formats across cells and SFs up to the SF and the cell, and a total counter DAI providing a total number of DL DCI formats across cells and SFs up to the SF. Relative to the operation inFIG. 18, a (cell/time-domain) counter DAI replaces a cell-domain relative counter DAI. A resulting functionality is practically equivalent.

FIG. 20illustrates a determination and arrangement for a HARQ-ACK information payload using a value of a counter DAI and a value of a total DAI for a TDD system according to this disclosure.

The eNB102configures UE114for PDSCH transmissions in ten cells of a TDD system where a bundling window size includes four SFs. In a first SF, SF#02010, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#2, Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=1 for Cell#2, a value VDAIDL-CT=2 for Cell#5, and a value VDAIDL-CT=3 for Cell#7and a total counter DAI in each of the three DL DCI formats has a value VDAI,TDL-T=3. In a second SF, SF#12020, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#3, Cell#6, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=4 for Cell#3, a value VDAIDL-CT=5 for Cell#6, and a value VDAIDL-CT=6 for Cell#7and a total counter DAI in each of the three DL DCI formats has a value VDAI,TDL-T=6. In a third SF, SF#22030, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=7 for Cell#5and a value VDAIDL-CT=8 for Cell#7and a total counter DAI in each of the two DL DCI formats has a value VDAI,TDL-T=8. In a fourth SF, SF#32040, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#3and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=9 for Cell#3and a value VDAIDL-CT=10 for Cell#7and a total counter DAI in each of the two DL DCI formats has a value VDAI,TDL-CT=10. For SF#0, SF#1, and SF#2, a determination and arrangement of HARQ-ACK information using a value of a counter DAI can be as inFIG. 19. A usefulness of the total counter DAI VDAI,TDL-Tappears in SF#3where UE114detects a DL DCI format scheduling a PDSCH in Cell#3but fails to detect a DL DCI format scheduling a PDSCH in Cell#7. Without the inclusion of the total counter DAI VDAI,TDL-Tin DL DCI formats, UE114is unable to determine that UE114failed to detect a DL DCI format scheduling a PDSCH in a cell with index larger than the index of Cell#3. With the inclusion of the total counter DAI VDAI,TDL-Tin DL DCI formats, based on the VDAI,TDL-Tvalue in the DL DCI format scheduling PDSCH in Cell#3(in SF#3) that UE114detects, UE114can determine that UE114failed to detect a DL DCI format scheduling a PDSCH in a cell with index larger than the index of Cell#3.

DL DCI Format Transmission in a CSS

A DL DCI format, such as DCI format 1A, that eNB102transmits in a CSS of a primary cell and schedules a PDSCH transmission on a primary cell does not include new fields for a (cell/time-domain) counter DAI and for a (time-domain) total counter DAI for a FDD system or for a total counter DAI for a TDD system. This is because a size of DCI format 1A when transmitted in a CSS needs to be same as a size of a DCI format 3/3A that is transmitted in the CSS and needs to be decoded by a group of UEs where at least some UEs in the group of UEs can be unaware of a change in the size of DCI format 1A in case a counter DAI or a total DAI are included in DCI format 1A.

For a FDD system, when UE114detects a DCI format 1A that is transmitted in a CSS and schedules a PDSCH on a primary cell, and UE114also detects at least one other DL DCI format that is transmitted in a USS and schedules a PDSCH reception on a secondary cell, a value for a counter DAI and a value for a total DAI in the at least one other DL DCI format counts the transmission of DCI format 1A and UE114places HARQ-ACK information for DCI format 1A in a first position of an associated HARQ-ACK codeword.

For a TDD system, when UE114detects a DCI format 1A in a CSS in a SF of a bundling window that schedules a PDSCH on a primary cell, and UE114also detects at least one other DL DCI format in a USS in the SF or in a later SF of the bundling window, a value for a counter DAI and a value for a total DAI in the at least one other DL DCI format includes counting of DCI format 1A. UE114places HARQ-ACK information for DCI format 1A in a first position for HARQ-ACK information that UE114determines for the SF. The first position for HARQ-ACK information that UE114determines for the SF is the first position in an associated HARQ-ACK codeword only when the SF is the first SF in the bundling window.

FIG. 21illustrates a determination and arrangement for a HARQ-ACK information payload when a DL DCI format is transmitted in a CSS for a TDD system according to this disclosure.

The eNB102configures UE114for PDSCH transmissions in ten cells of a TDD system where a bundling window size includes four SFs. In a first SF, SF#02010, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#2, Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=1 for Cell#2, a value VDAIDL-CT=2 for Cell#5, and a value VDAIDL-CT=3 for Cell#7and a total DAI in each of the three DL DCI formats has a value VDAI,TDL-T=3. In a second SF, SF#12020, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#0, Cell#6, and Cell#7and the DL DCI format that schedules PDSCH transmission in Cell#0is transmitted in a CSS and does not include a total DAI. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=4 for Cell#0, a value VDAIDL-CT=5 for Cell#6, and a value VDAIDL-CT=6 for Cell#7and a total DAI in the second and third DL DCI formats of the three DL DCI formats has a value VDAI,TDL-T==6. In a third SF, SF#22030, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=7 for Cell#5and a value VDAIDL-CT=8 for Cell#7and a total DAI in each of the two DL DCI formats has a value VDAI,TDL-T=8. In a fourth SF, SF#32040, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#0and Cell#7and the DL DCI format that schedules PDSCH transmission in Cell#0is transmitted in a CSS and does not include a total DAI. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=9 for Cell#0and a value VDAIDL-CT=10 for Cell#7and a counter DAI in the second of the two DL DCI formats has a value VDAIDL-T=10. HARQ-ACK information for the DL DCI format transmitted in the CSS in SF#12120is placed fourth in a HARQ-ACK codeword as a respective counter DAI value is VDAIDL-CT=4 and a total DAI value in SF#0is VDAI,TDL-T=3. HARQ-ACK information for the DL DCI format transmitted in the CSS in SF#32140is placed ninth in the HARQ-ACK codeword as a respective counter DAI value is VDAIDL-CT=9 and a total DAI value in SF#2is VDAI,TDL-T=8.

Resolution of Error Cases

It is also possible that UE114fails to detect any transmitted DL DCI format in SFs after a last SF where UE114detects a DL DCI format, for example as inFIG. 19. Then, regardless of DAI types in a DL DCI format, UE114cannot determine a correct HARQ-ACK information payload. The eNB102can resolve this ambiguity using one of the four previously described approaches. For example, according to the third approach and for a TDD system and for the exemplary case inFIG. 19orFIG. 20orFIG. 21, eNB102can attempt detection and perform a CRC check (determine whether or not a CRC checksum is zero) for each of the four following HARQ-ACK information payload values corresponding to the following(a) UE114detects at least one DL DCI format in SF#0and does not detect any DL DCI format in SF#1and SF#2and SF#3(UE114determines a first HARQ-ACK information payload, can be considered as the least likely scenario)(b) UE114detects at least one DL DCI format in SF#1and does not detect any DL DCI format in SF#2and SF#3(UE114determines a second HARQ-ACK information payload, can be considered as the second least likely scenario)(c) UE114detects at least one DL DCI format in SF#2and does not detect any DL DCI format in SF#3(UE114determines a third HARQ-ACK information payload, can be considered as the second most likely scenario)(d) UE detects at least one DL DCI format in SF#3(UE114determines a fourth HARQ-ACK information payload, can be considered as the most likely scenario)

When UE114transmits HARQ-ACK information using a PUCCH format that depends on a HARQ-ACK information payload, for example as described inFIG. 13, eNB102can attempt detection of multiple PUCCH formats. For example, when UE114determines a first HARQ-ACK information payload, UE114can use a PUCCH Format 3 while when UE114determines a second HARQ-ACK information payload, UE114can use a PUCCH Format 4 having a PUSCH-based structure. The eNB102can determine whether UE114transmits a PUCCH Format 3 by detecting a received energy in a resource that UE114can use to transmit the PUCCH Format 3 (DTX detection). The eNB102can determine whether UE114transmits a PUCCH Format 4 by detecting a received energy in a resource that UE114can use to transmit the PUCCH Format 4 or by relying on a check of a CRC that is included with the HARQ-ACK information payload in an encoded codeword when UE114uses PUCCH Format 4.

FIG. 22illustrates a procedure for eNB102to detect an HARQ-ACK codeword in a PUCCH using a CRC check or, in case of multiple possible PUCCH formats, a DTX detection for some of the PUCCH formats according to this disclosure.

The eNB102first decodes a HARQ-ACK codeword according to a HARQ-ACK information payload, a PUCCH format, and a PUCCH resource that eNB102expects UE114to use in response to transmissions of DL DCI formats from eNB102to UE114in one or more SFs2210. When a check for a CRC, when included in an encoded HARQ-ACK codeword, is positive (CRC checksum is zero)2220, eNB102considers a HARQ-ACK information obtained from a decoded HARQ-ACK codeword as valid2230. It is also possible that an encoded HARQ-ACK codeword does not include a CRC, such as when UE114uses a PUCCH format 3, and in such case eNB102can determine whether UE114transmits a respective PUCCH based on energy detection at a respective PUCCH resource (absence of DTX detection). When the CRC check is not positive (CRC checksum is not zero) or when eNB102detects DTX, eNB102proceeds to decode a HARQ-ACK codeword according to a next smaller HARQ-ACK information payload, relative to an expected HARQ-ACK information payload based on the transmitted DL DCI formats, and a respective PUCCH format and a PUCCH resource2240and repeats step2220. For example, for transmissions of DL DCI formats as inFIG. 19orFIG. 20, an expected HARQ-ACK payload corresponds to one for DL DCI formats transmitted in four SFs (ten DL DCI formats) while a next smaller HARQ-ACK information payload corresponds to DL DCI formats transmitted in the first three SFs (eight DL DCI formats). When the CRC check is not positive, eNB102proceeds to decode a HARQ-ACK codeword first according to a HARQ-ACK information payload that corresponds to DL DCI formats transmitted in the first two SFs (six DL DCI formats) and then, when the CRC check is also not positive, according to a HARQ-ACK information payload that corresponds to DL DCI formats transmitted in the first SF (three DL DCI formats). The above steps for the eNB102decoding attempts can also be performed in parallel or with a different order.

Determination of Payload and Arrangement of Information Bits in a Codeword for HARQ-ACK Transmission in a PUSCH

For a FDD system, when a cell-domain DAI in a DL DCI format scheduling a PDSCH transmission to UE114in a cell includes both a counter of transmitted DL DCI formats (or PDSCH transmissions) and either a forward counter of DL DCI format or a total number of DL DCI formats (or PDSCH transmissions), UE114can determine a number of DL DCI formats that eNB102transmits to UE114in a SF to schedule PDSCH transmissions (including SPS PDSCH release) in respective cells. UE114can also determine an order of respective cell indexes to arrange respective HARQ-ACK information in a codeword according to an ascending order of cell indexes. Then, assuming that either spatial-domain bundling applies or reported HARQ-ACK information for a cell includes two HARQ-ACK information bits regardless of a PDSCH TM when a PDSCH TM for at least one cell supports two data TBs (otherwise, by default, reported HARQ-ACK information for all cells includes 1 HARQ-ACK bit), UE114can determine an HARQ-ACK payload to transmit in a PUSCH in a same manner as in a PUCCH and an UL DAI in an UL DCI format scheduling a PUSCH transmission from UE114is not needed. An error case happens only when UE114fails to detect all DL DCI that eNB102transmits to UE114in a last SF within a bundling window.

For a TDD system, when a DL DCI format includes both a cell-domain DAI and a time-domain DAI, where for example the cell-domain DAI can be a counter of DL DCI formats (or PDSCH transmissions) in a SF according to an ascending order of a respective cell index and the time-domain DAI can be a total counter of DL DCI formats (or PDSCH transmissions) in past SF and a present SF of a same bundling window, or when a single counter DAI operates in the joint cell/time-domain (cell-first mapping of DAI values), UE114can determine a number of DL DCI formats that eNB102transmits to UE114in a bundling window to schedule PDSCH transmissions in respective cells and SFs. UE114can also determine an order of respective cell indexes and SFs to arrange respective HARQ-ACK information in a codeword according to an ascending order of cell indexes per SF and then according to an ascending order of SFs. Then, UE114can determine an HARQ-ACK payload to transmit in a PUSCH. An error case occurs when UE114fails to detect all transmitted DL DCI formats (or PDSCH transmissions) that eNB102transmits to UE114in a last SF within bundling window.

To avoid error cases where UE114can have a different understanding than eNB102of a number or an order of DL DCI formats transmitted from eNB102to UE114, a DAI field can be included in an UL DCI format scheduling a PUSCH transmission from UE114. The DAI field can indicate a total number of transmitted DL DCI formats that schedule PDSCH transmissions to UE114(or can indicate a total number of PDSCH transmissions), either in a SF for a FDD system or in a bundling window for a TDD system. Otherwise, when error cases are practically immaterial, a DAI field does not need to be included or used in an UL DCI format scheduling a PUSCH transmission and UE114determines a HARQ-ACK codeword in a same manner as for transmission in a PUCCH.

For a FDD system, when UE114adjusts a PUSCH transmission based on a detected UL DCI format, UE114can obtain a DAI value, VDAIUL-C. UE114can use VDAIUL-Cto determine an HARQ-ACK information payload, OHARQ-ACK, to multiplex in the PUSCH.

When UE114is configured with a maximum of C cells, a cell-domain total counter DAI field, or simply DAI field, in an UL DCI can include, for example, 2 bits having a mapping to respective numeric values VDAIUL-Cas in Table 6. Although each combination of the two bits can map to multiple numeric values, an error occurs only when UE114fails to detect three successive (based on a cell index) DL DCI formats and, for typical block error rate (BLER) values of 1 e-2 that UE114fails to detect a DCI format, this is an immaterial event.

TABLE 6Cell-Domain Total DAI Values in an UL DCI Format for a FDD SystemDAINumber of DL Cells with PDSCHMSB,transmissions and with PDCCH/EPDCCHLSBVDAIUL-Cindicating DL SPS release0, 011 or 5 or 9 or 13 or 17 or 21 or 25 or 29 . . . or C − 30, 122 or 6 or 10 or 14 or 18 or 22 or 26 or 30 . . . or C − 21, 033 or 7 or 11 or 15 or 19 or 23 or 27 or 31 . . . or C − 11, 140 or 4 or 8 or 12 or 16 or 20 or 24 or 28 or 32 . . . or C

It is OHARQ-ACK=VDAIUL-C(for 1 bit HARQ-ACK per DL DCI format; otherwise, it is OHARQ-ACK=2·VDAIUL-C) unless VDAIUL-C=4 and UDAICell+NSPS=0 (UE114does not detect a DL DCI format scheduling a PDSCH transmission and does not have a SPS PDSCH transmission in a SF) and then UE114does not transmit HARQ-ACK in a PUSCH. A spatially bundled HARQ-ACK information bit with index oHARQ-ACK, 0≦oHARQ-ACKis associated with a PDSCH transmission scheduled by a DL DCI format with cell-domain DAI value oHARQ-ACK+1 where UE114sets a value of the HARQ-ACK information bit with index oHARQ-ACKto a NACK/DTX value when UE114does not detect a DL DCI format scheduling a PDSCH transmission and having a counter DAI value of VDAIDL-C=oHARQ-ACK+1 (UE114determines existence of the DL DCI format from a counter DAI or from a total DAI in a next DL DCI format or from the DAI in the UL DCI format). When NSPS>0, a HARQ-ACK information bit associated with a SPS PDSCH transmission is assigned index OHARQ-ACK−1 (placed last in a HARQ-ACK codeword).

FIG. 23illustrates a determination and arrangement for a HARQ-ACK information payload transmission in a PUSCH transmission using a relative counter DAI value in a DL DCI format scheduling a PDSCH transmission and a total DAI value in an UL DCI format scheduling a PUSCH transmission for a FDD system according to this disclosure.

UE114is configured by eNB102for PDSCH transmissions in ten cells of a FDD system. In a first case, UE114detects a DL DCI format that schedules a PDSCH transmission in Cell#2and includes a cell-domain counter DAI field having a value VDAIDL-C=1 2310. UE114fails to detect DL DCI formats scheduling PDSCH transmissions for Cell#52312and Cell#72314. UE114also detects an UL DCI format scheduling a PUSCH transmission in a SF where eNB102expects UE114to transmit HARQ-ACK in response to PDSCH transmissions in Cell#2, Cell#5, and Cell#7where the UL DCI format includes a cell-domain total DAI field having a value VDAIUL-C=3 2320. Based on the value of VDAIDL-C=1 and VDAIUL-C=3, UE114determines that UE114failed to detect 2 DL DCI formats scheduling PDSCH transmissions in cells with index larger than 2 (the index for Cell#2) and UE114generates a HARQ-ACK codeword of {x, NACK/DTX, NACK/DTX}2330for transmission in the PUSCH where ‘x’ is either ACK or NACK/DTX depending on a correct or incorrect detection of data TBs conveyed in the PDSCH transmission in Cell#2.

In a second case, UE114detects a DL DCI format that schedules a PDSCH transmission in Cell#7and includes a cell-domain counter DAI field having a value VDAIDL-CT=32344. UE114fails to detect DL DCI formats scheduling PDSCH transmissions for Cell#22340, Cell#52342and Cell#92346. UE114also detects an UL DCI format scheduling a PUSCH transmission in a SF where eNB102expects UE114to transmit HARQ-ACK in response to PDSCH transmissions in Cell#2, Cell#5, Cell#7, and Cell#9, where the UL DCI format includes a cell-domain total DAI field having a value VDAIUL-C=4 2350. Based on the values of VDAIDL-C=3 and VDAIUL-C=4, UE114determines that UE114failed to detect 2 DL DCI formats scheduling PDSCH transmissions in cells with index smaller than 7 (the index for Cell#7) and 1 DL DCI format scheduling a PDSCH transmission in a cell with index larger than 7 and UE114generates a HARQ-ACK codeword of {NACK/DTX, NACK/DTX, x, NACK/DTX}2360for transmission in the PUSCH where ‘x’ is either ACK or NACK/DTX depending on a correct or incorrect detection of data TBs conveyed in the PDSCH transmission in Cell#7. Therefore with a combination of a cell-domain counter DAI field in DL DCI formats scheduling PDSCH transmissions and a cell-domain total counter (that counts all DL DCI formats scheduling PDSCH transmissions in a SF) in an UL DCI format scheduling a PUSCH transmission, UE114can identify a HARQ-ACK payload and arrangement of HARQ-ACK information bits in a codeword in a manner that is same as expected by eNB102.

In case of a SPS PUSCH transmission from UE114, there is no UL DCI format scheduling the SPS PUSCH transmission and UE114cannot obtain a VD value. Relying only on a cell-domain counter DAI field in DL DCI format can result to UE114transmitting an incorrect HARQ-ACK payload in the SPS PUSCH as UE114can fail to detect DL DCI formats scheduling PDSCH transmissions in cells with larger indexes than a largest index of a cell where UE114detects a DL DCI format. A first alternative is for UE114to transmit HARQ-ACK information for all configured cells. A second alternative is to rely on eNB102to resolve a HARQ-ACK payload ambiguity, for example as described inFIG. 22. A third alternative is to devise means for circumventing a HARQ-ACK payload ambiguity problem.

A first approach for the third alternative is to include a forward relative counter DAI field or a total DAI field, in addition to a cell-domain counter DAI field, in DL DCI formats as was previously described inFIG. 14orFIG. 15, respectively.

A second approach for the second alternative is for UE114to include information for a number of received PDSCH transmissions together with, but separately encoded, the HARQ-ACK information. The second approach can be conditioned on UE114multiplexing HARQ-ACK information in a PUSCH transmission that is not scheduled by an UL DCI format. The eNB102can first decode an indicator field with value Irxtransmitted by UE114and indicating a number of PDSCH transmissions (or a number of DL DCI formats) UE114received. Based on that information, eNB102can determine a HARQ-ACK information payload transmitted by UE114and accordingly decode HARQ-ACK information and data information in the PUSCH. For example, an indicator field can include 2 bits where a mapping of the 2 bits can be as in Table 6 by replacing VDAIUL-Cwith Irxand replacing ‘transmissions’ with ‘receptions’.

FIG. 24illustrates a method for a UE to transmit HARQ-ACK information by indicating a number of detected DL DCI formats according to this disclosure.

UE114determines a number of received PDSCHs (or, equivalently by also accounting for SPS PDSCH release, a number of detected DL DCI formats) and generates and encodes an indicator for the number2410. UE114also generates and encodes, separately than the indicator, HARQ-ACK information bits for respective received PDSCH receptions2420. UE114multiplexes and transmits to eNB102the indicator codeword and a HARQ-ACK codeword in a same channel (PUSCH or PUCCH)2430. The eNB102receives the channel that conveys the indicator codeword and the HARQ-ACK codeword2440. The eNB102decodes the indicator codeword to obtain a number of PDSCH transmissions that UE114received and determine a payload for the HARQ-ACK codeword2450. Based on the determined payload for the HARQ-ACK codeword, eNB102decodes the HARQ-ACK codeword to obtain the HARQ-ACK information bits2460.

For a TDD system, a DAI field with value VDAIUL-CTin an UL DCI format scheduling a PUSCH transmission can provide a total number of PDSCH transmissions (or DL DCI format transmissions by including SPS PDSCH release) over both a cell domain and a time domain or, equivalently, the DAI field can provide a total number of PDSCH transmissions over all cells and over all SFs of a bundling window (cell/time-domain DAI). A mapping for a value VDAIUL-CTof the DAI field can be as in Table 6 by replacing VDAIUL-Cwith VDAIUL-CTand considering PDSCH transmissions over the entire bundling window.

A first alternative for determining an arrangement of HARQ-ACK information bits in a codeword is for UE114to use a value of a DAI field in an UL DCI format scheduling a PUSCH transmission, a value VDAIDL-Cof a cell-domain counter DAI field, and a value VDAI,TDL-Tof a time-domain total DAI field in DL DCI formats scheduling PDSCH transmissions in configured cells and SFs of a bundling window. A counter DAI field provides a relative counter of a respective DL DCI format according to an index of a cell with a respective PDSCH transmission. A total DAI field in a DL DCI format provides a total counter for DL DCI formats scheduling PDSCH transmissions in all cells and in all previous SFs and a current SF of a bundling window. Using a value VDAIUL-CTof a DAI in an UL DCI format, UE114can determine whether UE114failed to detect some DL DCI formats, particularly in SFs of a bundling window after a last SF of the bundling window where UE114detects a DL DCI format. Using VDAIDL-C, UE114can determine whether UE114failed to detect one or more DL DCI formats scheduling PDSCHs in cells with smaller indexes than an index of a cell where UE114detects a DL DCI format that includes VDAIDL-Cand schedules a PDSCH transmission in the cell in a SF. Using VDAI,TDL-T, UE114can determine whether UE114failed to detect one or more DL DCI formats scheduling PDSCH transmissions in cells with larger indexes than an index of a cell where UE114detects a DL DCI format that includes VDAI,TDL-Tand schedules a PDSCH transmission in the cell in a SF of a bundling window and also determine whether UE114failed to detect one or more DL DCI formats scheduling PDSCH transmissions in cells in previous SFs of the bundling window.

FIG. 25illustrates a determination and arrangement of HARQ-ACK information in a PUSCH using a counter DAI value and a total DAI value in a DL DCI format scheduling a PDSCH transmission and a DAI value in an UL DCI format scheduling a PUSCH transmission for a TDD system according to this disclosure.

UE114is configured by eNB102for PDSCH transmissions in ten cells of a TDD system where a bundling window size includes four SFs. In a first SF, SF#02510, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#2, Cell#5, and Cell#7. A cell-domain counter DAI in a respective DL DCI format has a value VDAIDL-C=1 for Cell#2, a value VDAIDL-C=2 for Cell#5, and a value VDAIDL-C=3 for Cell#7and a total DAI in each of the three DL DCI formats has a value VDAI,TDL-T=3. In a second SF, SF#12520, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#3, Cell#6, and Cell#7. A cell-domain counter DAI in a respective DL DCI format has a value VDAIDL-C=1 for Cell#3, a value VDAIDL-C=2 for Cell#6, and a value VDAIDL-C=3 for Cell#7and a total DAI in each of the three DL DCI formats has a value VDAI,TDL-T=6. In a third SF, SF#22530, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#5, and Cell#7. A cell-domain counter DAI in a respective DL DCI format has a value VDAIDL-C=1 for Cell#5and a value VDAIDL-C=2 for Cell#7and a total DAI in each of the two DL DCI formats has a value VDAI,TDL-T=8. In a fourth SF, SF#32540, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#3and Cell#7. A cell-domain counter DAI in a respective DL DCI format has a value VDAIDL-C=1 for Cell#3and a value VDAIDL-C=2 for Cell#7and a total DAI in each of the three DL DCI formats has a value VDAI,TDL-T=10.

In SF#02510, UE114detects the first and third DL DCI formats and fails to detect the second DL DCI format. From the values CDAIDL-C=1 and VDAIDL-C=3 of the cell-domain counter DAI in the two detected DL DCI formats in SF#0, UE114determines that UE114failed to detect a DL DCI format for a cell with index larger than 2 and smaller than 7. From the value VDAI,TDL-T=3 of the total DAI in SF#0, UE114determines that UE114did not fail to detect any other DL DCI format. Therefore, UE114can determine and arrange HARQ-ACK information bits in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in SF#0.

In SF#12520, UE114detects the first and second DL DCI formats and fails to detect the third DL DCI format. From the values VDAIDL-C=1 and VDAIDL-C=2 of the cell-domain counter DAI in the two detected DL DCI formats in SF#1, UE114determines that UE114did not fail to detect any DL DCI format for a cell with index smaller than 6. From the value VDAI,TDL-T=6 of the total DAI in SF#1, UE114determines that UE114failed to detect a DL DCI format and, using the value of the cell-domain counter DAI field in the DL DCI format for Cell#6, UE114determines that the DL DCI format that UE114failed to detect is for a cell with index larger6. Therefore, UE114can determine and arrange HARQ-ACK information bits in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in SF#1.

In SF#22530, UE114detects both the first and second DL DCI formats. From the values VDAIDL-C=1 and VDAIDL-C=2 of the cell-domain counter DAI in the two detected DL DCI formats in SF#2, UE114determines that UE114did not fail to detect any DL DCI format for a cell with index smaller than 7. From the value VDAI,TDL-T=8 of the total DAI in SF#2, UE114determines that UE114did not fail to detect a DL DCI format for a cell with index larger than 7. Therefore, UE114can determine and arrange HARQ-ACK information bits in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in SF#2.

In SF#32540, UE114fails to detect both the first and second DL DCI formats. From the value VDAIUL-CT=10 of the cell/time-domain total DAI in the UL DCI format scheduling a PUSCH transmission and from the determinations in previous SFs of the bundling window, UE114can determine that UE114failed to detect two DL DCI formats in SF#3. Therefore, UE114can determine and arrange HARQ-ACK information bits in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in SF#4.

For brevity, in the following, a cell/time-domain relative counter DAI is referred to as counter DAI and a time-domain total counter DAI is referred to as total DAI.

A second alternative for determining an arrangement of HARQ-ACK information bits in a codeword is for UE114to use a value of a DAI field in an UL DCI format scheduling a PUSCH transmission and a value VDAIDL-CTof a counter DAI field in DL DCI format scheduling PDSCH transmissions in configured cells and SFs of a bundling window. A counter DAI field in a DL DCI format scheduling a PDSCH transmission in a cell can provide a relative counter for DL DCI formats scheduling PDSCH transmissions in all cells and in all previous SFs and for cell indexes up to the index of the cell in a current SF of a bundling window. Using VDAIUL-CT, UE114can determine whether UE114failed to detect some DL DCI formats scheduling PDSCH transmissions, particularly in SFs of a bundling window after a last SF of the bundling window where UE114detects a DL DCI format scheduling a PDSCH transmission.

FIG. 26illustrates a determination and arrangement for a HARQ-ACK information payload transmission in a PUSCH using a counter DAI value in a DL DCI format scheduling a PDSCH transmission and a DAI value in an UL DCI format scheduling a PUSCH transmission for a TDD system according to this disclosure.

UE114is configured by eNB102for PDSCH transmissions in ten cells of a TDD system where a bundling window size includes four SFs. In a first SF, SF#02610, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#2, Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=1 for Cell#2, a value VDAIDL-CT=2 for Cell#5, and a value VDAIDL-CT=3 for Cell#7. In a second SF, SF#12620, eNB102transmits to UE114three DL DCI formats scheduling respective PDSCH transmissions in Cell#3, Cell#6, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=4 for Cell#3, a value VDAIDL-CT=5 for Cell#6, and a value VDAIDL-CT=6 for Cell #7. In a third SF, SF#22630, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#5, and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=7 for Cell#5and a value VDAIDL-CT=8 for Cell#7. In a fourth SF, SF#32640, eNB102transmits to UE114two DL DCI formats scheduling respective PDSCH transmissions in Cell#3and Cell#7. A counter DAI in a respective DL DCI format has a value VDAIDL-CT=9 for Cell#3and a value VDAIDL-CT=10 for Cell#7.

In SF#02610, UE114detects the first and third DL DCI formats and fails to detect the second DL DCI format. From the values VDAIDL-CT=1 and VDAIDL-CT=3 of the counter DAI in the two detected DL DCI formats in SF#0, UE114determines that UE114failed to detect a DL DCI format for a cell with index larger than 2 and smaller than 7. Therefore, UE114can determine and arrange HARQ-ACK information bits as {x, NACK/DTX, x}, where ‘x’ represents either an ACK or a NACK/DTX, in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in SF#0.

In SF#12620, UE114detects the first and second DL DCI formats and fails to detect the third DL DCI format. From the values VDAIDL-CT=4 and VDAIDL-CT=5 of the counter DAI in the two detected DL DCI formats in SF#1, UE114determines that UE114did not fail to detect any other DL DCI format in SF#0. For SF#0and SF#1, UE114can determine and arrange HARQ-ACK information bits as {x, NACK/DTX, x, x, x}.

In SF#22630, UE114detects both the first and second DL DCI formats. From the value VDAIDL-CT=7 of the counter DAI in the detected DL DCI format for Cell#5in SF#2, UE114determines that UE114failed to detect a DL DCI format in SF#1for a cell with larger index than Cell#6or in SF#2with a cell with smaller index than Cell#5. From the value VDAIDL-CT=8 of the counter DAI in the detected DL DCI format for Cell#7in SF#2, UE114determines that UE114did not fail to detect a DL DCI format in SF#2for a cell with smaller index than Cell#7. For SF#0, SF#1, and SF#2, UE114can determine and arrange HARQ-ACK information bits as {x, NACK/DTX, x, x, x, NACK/DTX, x, x}.

In SF#32640, UE114fails to detect both the first and second DL DCI formats. From the value VDAIUL-CT=10 of the UL DAI in the UL DCI format scheduling a PUSCH transmission and from the determinations in previous SFs of the bundling window, UE114can determine that UE114failed to detect two DL DCI formats for cells with larger index than Cell#7in SF#2or for any cells in SF#3. For SF#0, SF#1, SF#2, and SF#3, UE114can determine and arrange HARQ-ACK information bits as {x, NACK/DTX, x, x, x, NACK/DTX, x, x, NACK/DTX, NACK/DTX}. Therefore, UE114can determine and arrange the HARQ-ACK information bits in response to receptions or absence of receptions of PDSCH transmissions scheduled by DL DCI formats transmitted in all SFs of a bundling window.

It can be observed that a functionality of a DAI value, VDAIUL-CT, in an UL DCI format is same as a functionality of a total DAI value, VDAI,TDL-T, in a DL DCI format. When eNB102transmits DL DCI formats to UE114in a number of SFs within a bundling window, unless UE114fails to detect all DL DCI formats in a last SF from the number of SFs (error case), VDAI,TDL-Tis same as VDAIUL-CTand, as previously described, a use of a DAI in an UL DCI format can be omitted. A use of a DAI value in an UL DCI format can also be omitted when UE114transmits HARQ-ACK codeword in a PUCCH in a same SF where UE114transmits a PUSCH scheduled by an UL DCI format that includes an UL DAI value. When an UL DAI field already exists in UL DCI formats, as in case of a TDD system (see also REF 2 and REF 3), an interpretation of the UL DAI field can be different depending on whether UE114is configured with up to 5 DL cells or with more than 5 DL cells. In the former case, a functionality of the UL DAI field can be as described in REF 2 and REF 3. In the latter case, a functionality of the UL DAI field can be same as for a total DAI field in a DL DCI format and UE114can apply a same mechanism for determining a HARQ-ACK codeword for transmission in a PUCCH and for transmission in a PUSCH. For a SPS PUSCH transmission or for a non-adaptive (not scheduled by an UL DCI format) retransmission of a data TB in a PUSCH, UE114determines a same HARQ-ACK codeword for transmission in a PUSCH or in a PUCCH using values VDAIDL-CTof counter DAI fields and values VDAI,TDL-Tof total DAI fields in DL DCI formats. A same determination for a HARQ-ACK codeword can also apply when a PUSCH transmission is scheduled by an UL DCI format or, to protect against the error case, the UL DAI field value VDAIUL-CTreplaces the total counter DAI value VDAI,TDL-Tin determining the HARQ-ACK codeword while using a same mechanism for the determination as for transmission in a PUCCH.

Allocation of Resources for HARQ-ACK Transmission in a PUSCH

In Equation 2, a number of REs, MREreq, required for multiplexing HARQ-ACK information in a PUSCH depends on a MCS for an initial data TB transmission, through the term

MscPUSCH⁢-⁢initial⁢·NsymbPUSCH⁢-⁢initial/∑r=0C-1⁢Kr,
on a HARQ-ACK information payload OHARQ-ACKand on an offset βoffsetPUSCHthat intents to decouple a data information BLER from a HARQ-ACK information BLER. For a given HARQ-ACK payload, a HARQ-ACK BLER depends on a coding method used to encode the HARQ-ACK information bits. For example, for a RM code, a coding gain can be such MREreqincreases linearly with O and therefore using a single βoffsetPUSCHvalue can be sufficient. However, for a TBCC, a coding gain can be non-linear with O and UE114can be configured several βoffsetPUSCHvalues for respective values of O thereby making βoffsetPUSCHa function of O. For example, for HARQ-ACK payloads up to 128 bits and use of TBCC for HARQ-ACK payloads above 22 bits, eNB102can configure three βoffsetPUSCHvalues to UE114; a first value, βoffsetPUSCH(O1), for use with HARQ-ACK payloads between 23 bits and 60 bits, a second value, βoffsetPUSCH(O2), for use with HARQ-ACK payloads between 61 bits and 96 bits, and a third value, βoffsetPUSCH(O3), for use with HARQ-ACK payloads between 97 bits and 128 bits.

A coarser or a finer granularity for a range of HARQ-ACK payloads can be achieved by configuring, respectively, a smaller number or a larger number of βoffsetPUSCHvalues. When eNB102configures a single βoffsetPUSCHvalue to UE114for HARQ-ACK payloads encoded by a TBCC that range from O1bits to O2bits, where for example O1=23 and O2=128, there can be at least two approaches for eNB102to select the βoffsetPUSCHvalue. In a first approach, eNB102can select the βoffsetPUSCHvalue as the one providing a value of M that can achieve a desired BLER for a HARQ-ACK information payload near the mid-point of O1and O2. In a second approach, in order to ensure a desired BLER at the expense of occasional unnecessary use of resources for HARQ-ACK transmission in a PUSCH, eNB102can select O1as a reference payload for determining a βoffsetPUSCHvalue since coding gains increase as an HARQ-ACK payload increases. Even when eNB102configures UE114with a single βoffsetPUSCHvalue when UE114uses a TBCC to encode HARQ-ACK information, eNB102separately configures UE114a first βoffsetPUSCHvalue for use in case of RM coding or repetition coding (for payloads up to 22 bits) and a second βoffsetPUSCHvalue for use in case of TBCC (for payloads above 22 bits).

Although the present disclosure has been described with example embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications that fall within the scope of the appended claims.