Patent Description:
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 wmobile 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. <CIT> relates to the transmission and reception of ACKnowledgements (ACK) signals. <CIT> discloses a method for transmitting Hybrid Automatic Repeat reQuest-ACKnowledgement (HARQ-ACK) feedback information. <CIT> discloses a method in which a user equipment transmits hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) information and a scheduling request (SR), in a communication system under a carrier aggregation environment.

Aspects of the present disclosure is to provide methods and apparatus for determining a resource and a power for a PUCCH format transmission.

Definitions for other certain words and phrases are provided throughout this disclosure. Those of ordinary skill in the art should understand that in many if not most instances such definitions apply to prior as well as future uses of such defined words and phrases.

This disclosure provides methods and apparatus for determining a resource and a power for a PUCCH format transmission.

Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless communication system.

One or more embodiments of the present disclosure relate to determining a power and a resource for a transmission of an uplink control channel in carrier aggregation 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> illustrates an example wireless network <NUM> according to this disclosure. The embodiment of the wireless network <NUM> shown in <FIG> is for illustration only.

As shown in <FIG>, the wireless network <NUM> includes an eNB <NUM>, an eNB <NUM>, and an eNB <NUM>. The eNB <NUM> communicates with the eNB <NUM> and the eNB <NUM>. The eNB <NUM> also communicates with at least one Internet Protocol (IP) network <NUM>, 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 eNB <NUM> provides wireless broadband access to the network <NUM> for a first plurality of user equipments (UEs) within a coverage area <NUM> of the eNB <NUM>. The first plurality of UEs includes a UE <NUM>, which may be located in a small business (SB); a UE <NUM>, which may be located in an enterprise (E); a UE <NUM>, which may be located in a WiFi hotspot (HS); a UE <NUM>, which may be located in a first residence (R); a UE <NUM>, which may be located in a second residence (R); and a UE <NUM>, which may be a mobile device (M) like a cell phone, a wireless laptop, a wireless PDA, or the like. The eNB <NUM> provides wireless broadband access to the network <NUM> for a second plurality of UEs within a coverage area <NUM> of the eNB <NUM>. The second plurality of UEs includes the UE <NUM> and the UE <NUM>. In some embodiments, one or more of the eNBs <NUM>-<NUM> may communicate with each other and with the UEs <NUM>-<NUM> using <NUM>, LTE, LTE-A, WiMAX, or other advanced wireless communication techniques.

It should be clearly understood that the coverage areas associated with eNBs, such as the coverage areas <NUM> and <NUM>, 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 network <NUM> (such as the eNBs <NUM>-<NUM> and/or the UEs <NUM>-<NUM>) support the adaptation of communication direction in the network <NUM>, and can provide support for DL or UL transmissions in carrier aggregation operation.

Although <FIG> illustrates one example of a wireless network <NUM>, various changes may be made to <FIG>. For example, the wireless network <NUM> could include any number of eNBs and any number of UEs in any suitable arrangement. Also, the eNB <NUM> could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network <NUM>. Similarly, each eNB <NUM>-<NUM> could communicate directly between them or with the network <NUM> and provide UEs with direct wireless broadband access to the network <NUM>. Further, the eNB <NUM>, <NUM>, and/or <NUM> could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

<FIG> illustrates an example UE <NUM> according to this disclosure. The embodiment of the UE <NUM> shown in <FIG> is for illustration only, and the other UEs in <FIG> could have the same or similar configuration.

As shown in <FIG>, the UE <NUM> includes an antenna <NUM>, a radio frequency (RF) transceiver <NUM>, transmit (TX) processing circuitry <NUM>, a microphone <NUM>, and receive (RX) processing circuitry <NUM>. The UE <NUM> also includes a speaker <NUM>, a controller/processor <NUM>, an input/output (I/O) interface (IF) <NUM>, an input <NUM>, a display <NUM>, and a memory <NUM>. The memory <NUM> includes an operating system (OS) program <NUM> and one or more applications <NUM>.

The RF transceiver <NUM> receives, from the antenna <NUM>, an incoming RF signal transmitted by an eNB or another UE. The RX processing circuitry <NUM> transmits the processed baseband signal to the speaker <NUM> (such as for voice data) or to the controller/processor <NUM> for further processing (such as for web browsing data).

The TX processing circuitry <NUM> receives analog or digital voice data from the microphone <NUM> or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the controller/processor <NUM>.

The controller/processor <NUM> can include one or more processors or other processing devices and can execute the OS program <NUM> stored in the memory <NUM> in order to control the overall operation of the UE <NUM>. For example, the controller/processor <NUM> could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver <NUM>, the RX processing circuitry <NUM>, and the TX processing circuitry <NUM> in accordance with well-known principles. In some embodiments, the controller/processor <NUM> includes at least one microprocessor or microcontroller.

The controller/processor <NUM> is also capable of executing other processes and programs resident in the memory <NUM>. In some embodiments, the controller/processor <NUM> is configured to execute the applications <NUM> based on the OS program <NUM> or in response to signals received from eNBs, other UEs, or an operator. The controller/processor <NUM> is also coupled to the I/O interface <NUM>, which provides the UE <NUM> with the ability to connect to other devices such as laptop computers and handheld computers. The I/O interface <NUM> is the communication path between these accessories and the controller/processor <NUM>.

The controller/processor <NUM> is also coupled to the input <NUM> (e.g., touchscreen, keypad, etc.) and the display <NUM>. The operator of the UE <NUM> can use the input <NUM> to enter data into the UE <NUM>. The display <NUM> may be a liquid crystal display or other display capable of rendering text and/or at least limited graphics, such as from web sites. The display <NUM> could also represent a touch-screen.

Part of the memory <NUM> could include a control or data signaling memory (RAM), and another part of the memory <NUM> could include a Flash memory or other read-only memory (ROM).

As described in more detail below, the transmit and receive paths of the UE <NUM> (implemented using the RF transceiver <NUM>, TX processing circuitry <NUM>, and/or RX processing circuitry <NUM>) support respective DL or UL transmissions in carrier aggregation operation.

As a particular example, the controller/processor <NUM> could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while <FIG> illustrates the UE <NUM> configured 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 in <FIG> could be replicated, such as when different RF components are used to communicate with the eNBs <NUM>-<NUM> and with other UEs.

<FIG> illustrates an example eNB <NUM> according to this disclosure. The embodiment of the eNB <NUM> shown in <FIG> is for illustration only, and other eNBs of <FIG> could have the same or similar configuration. However, eNBs come in a wide variety of configurations, and <FIG> does not limit the scope of this disclosure to any particular implementation of an eNB.

As shown in <FIG>, the eNB <NUM> includes multiple antennas 305a-305n, multiple RF transceivers 310a-310n, transmit (TX) processing circuitry <NUM>, and receive (RX) processing circuitry <NUM>. The eNB <NUM> also includes a controller/processor <NUM>, a memory <NUM>, and a backhaul or network interface <NUM>.

The RF transceivers 310a-310n receive, from the antennas 305a-305n, incoming RF signals, such as signals transmitted by UEs or other eNBs. The RF transceivers 310a-310n down-convert the incoming RF signals to generate IF or baseband signals.

The RF transceivers 310a-310n receive the outgoing processed baseband or IF signals from the TX processing circuitry <NUM> and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 305a-305n.

The controller/processor <NUM> can include one or more processors or other processing devices that control the overall operation of the eNB <NUM>. For example, the controller/processor <NUM> could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 310a-310n, the RX processing circuitry <NUM>, and the TX processing circuitry <NUM> in accordance with well-known principles. The controller/processor <NUM> could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor <NUM> could support beam forming or directional routing operations in which outgoing signals from multiple antennas 305a-305n are 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 eNB <NUM> by the controller/processor <NUM>. In some embodiments, the controller/processor <NUM> includes at least one microprocessor or microcontroller.

The backhaul or network interface <NUM> allows the eNB <NUM> to communicate with other devices or systems over a backhaul connection or over a network. For example, when the eNB <NUM> is implemented as part of a cellular communication system (such as one supporting <NUM>, LTE, or LTE-A), the interface <NUM> could allow the eNB <NUM> to communicate with other eNBs, such as eNB <NUM>, over a wired or wireless backhaul connection. When the eNB <NUM> is implemented as an access point, the interface <NUM> could allow the eNB <NUM> to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet).

As described in more detail below, the transmit and receive paths of the eNB <NUM> (implemented using the RF transceivers 310a-310n, TX processing circuitry <NUM>, and/or RX processing circuitry <NUM>) support respective DL or UL transmissions in carrier aggregation operation.

Although <FIG> illustrates one example of an eNB <NUM>, various changes may be made to <FIG>. For example, the eNB <NUM> could include any number of each component shown in <FIG>. As another particular example, while shown as including a single instance of TX processing circuitry <NUM> and a single instance of RX processing circuitry <NUM>, the eNB <NUM> could 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 eNB <NUM>, 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 LTE, such as UE <NUM>, to demodulate data or control signals or to perform measurements. To reduce CRS overhead, eNB <NUM> can transmit a CSI-RS with a smaller density in the time domain than a CRS (see also REF <NUM> and REF <NUM>). UE <NUM> can use either a CRS or a CSI-RS to perform measurements and a selection can be based on a transmission mode (TM) UE <NUM> is configured by eNB <NUM> for physical DL shared channel (PDSCH) reception (see also REF <NUM>). Finally, UE <NUM> can use a DMRS to demodulate data or control signals. The eNB <NUM> can transmit data information to UE <NUM> through a PDSCH. The transport channel transferring information from a PDSCH to higher layers is referred to as DL shared channel (DL-SCH). An eNB can transmit DCI to a UE through a DCI format transmission in a physical DL control channel (PDCCH).

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 UE <NUM>, 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 eNB <NUM>. The transport channel transferring information from a PUSCH to higher layers is referred to as UL shared channel (UL-SCH). When UE <NUM> simultaneously transmits data information and UCI, UE <NUM> can 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 eNB <NUM> whether UE <NUM> has data in its buffer, and channel state information (CSI) enabling eNB <NUM> to select appropriate parameters for PDSCH or PDCCH transmissions to UE <NUM>. 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 UE <NUM> does 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 <NUM>).

CSI can include a channel quality indicator (CQI) informing eNB <NUM> of a transport block size (TBS) having a modulation and coding scheme (MCS) that can be received by UE <NUM> with a predefined target block error rate (BLER), a precoding matrix indicator (PMI) informing eNB <NUM> how to combine signals from multiple transmitted antennas in accordance with a multiple input multiple output (MIMO) transmission principle, and a rank indicator (RI) indicating a transmission rank for a PDSCH (see also REF <NUM>). For example, UE <NUM> can determine a CQI from a signal-to-interference and noise ratio (SINR) measurement while also considering a configured PDSCH TM and the UE <NUM> receiver characteristics. A UE can use a CRS or a CSI-RS transmission from an eNB to determine a CSI (see also REF <NUM>). The eNB <NUM> can configure UE <NUM> to periodically transmit CSI (P-CSI) on a PUCCH or to dynamically transmit aperiodic CSI (A-CSI) on a PUSCH (see also REF2 and REF <NUM>).

UL RS can include DMRS and sounding RS (SRS). DMRS can be transmitted only in a BW of a respective PUSCH or PUCCH and eNB <NUM> can use a DMRS to demodulate information in a PUSCH or PUCCH. SRS can be transmitted by UE <NUM> in order to provide eNB <NUM> with a UL CSI (see also REF <NUM> and REF <NUM>).

The eNB <NUM> can schedule PDSCH transmission to UE <NUM> or PUSCH transmission from UE <NUM> through respective DCI formats conveyed by respective PDCCHs. DCI formats can also provide other functionalities (see also REF <NUM>).

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 <NUM> SFs, indexed from <NUM> to <NUM>, 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> illustrates an example UL SF structure for PUSCH transmission or PUCCH transmission according to this disclosure. The embodiment of the UL SF structure shown in <FIG> is 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 SF <NUM> includes two slots. Each slot <NUM> includes ASeNB,<NUM> symbols <NUM> where UE <NUM> transmits data information, UCI, or RS including one symbol per slot where UE <NUM> transmits DMRS <NUM>. A transmission BW includes frequency resource units that are referred to as resource blocks (RBs). Each RB includes ASeNB,<NUM> (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. UE <NUM> is assigned MPUXCH RBs for a total of <MAT> REs <NUM> for a PUSCH transmission BW ('X'='S') or for a PUCCH transmission BW ('X'='C'). A last SF symbol can be used to multiplex SRS transmissions <NUM> from one or more UEs. A number of UL SF symbols available for data/UCI/DMRS transmission is <MAT>. NSRS=<NUM> when a last SF symbol supports SRS transmissions from UEs that overlap at least partially in BW with a PUXCH transmission BW; otherwise, NSRS=<NUM>. Therefore, a number of total REs for a PUXCH transmission is <MAT>.

When the structure in <FIG> is used to transmit UCI (HARQ-ACK or P-CSI) 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> illustrates an example encoding and modulation process for UCI according to this disclosure. The embodiment of the encoding process shown in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

Upon determining that a number OUCI,<NUM> of UCI bits is larger than a predetermined value, a UE <NUM> controller (not shown) provides the UCI bits <NUM> to a CRC generator <NUM> that computes a CRC for the OUCI,<NUM> UCI bits and appends OCRC CRC bits, such as <NUM> CRC bits, to the OUCI,<NUM> UCI bits to result OUCI UCI and CRC bits <NUM>. An encoder <NUM>, such as a tail biting convolutional code (TBCC), encodes the output of OUCI bits. A rate matcher <NUM> performs rate matching to allocated resources, followed by a scrambler <NUM> to perform scrambling, a modulator <NUM> to modulate the encoded bits, for example using QPSK, an RE mapper <NUM>, and finally a transmitter for a transmission of a control signal <NUM>.

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

The eNB <NUM> receives a control signal <NUM> that is provided to a RE demapper <NUM> to perform RE demapping, a demodulator <NUM> to perform demodulation for a corresponding modulation scheme, a descrambler <NUM> to perform descrambling, a rate matcher <NUM> to perform rate matching, and a decoder <NUM>, such as a TBCC decoder, to perform decoding and provide OUCI UCI and CRC bits. A CRC extraction unit <NUM> separates OUCI,<NUM> UCI bits <NUM> and OCRC CRC bits <NUM>, and a CRC checking unit <NUM> computes a CRC check. When the CRC check passes (CRC checksum is zero), eNB <NUM> determines that the UCI is valid.

<FIG> illustrates 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 in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

UCI bits <NUM> from UE <NUM>, such as OP-CSI P-CSI information bits, when any, and OHARQ-ACK HARQ-ACK information bits, when any, but also a SR bit in a SF configured to UE <NUM> for SR transmission (not shown), are jointly encoded either by a first encoder <NUM>, for example using tail-biting convolutional coding (TBCC) or turbo coding (TC) and cyclic redundancy check (CRC) bits are included in each encoded codeword (see also REF <NUM>) or by a second encoder <NUM>, for example using Reed-Muller (RM) coding. An encoder selection is by a controller (e.g., controller/processor <NUM> of <FIG>) where, for example, the controller selects the TBCC encoder when a HARQ-ACK payload is larger than a predetermined value, such as <NUM> bits, and the controller selects the RM encoder when a HARQ-ACK payload is not larger than a predetermined value. Encoded bits are subsequently modulated by modulator <NUM>. A discrete Fourier transform (DFT) is obtained by DFT unit <NUM>, REs <NUM> corresponding to a PUCCH transmission BW are selected by selector <NUM>, an inverse fast Fourier transform (IFFT) is performed by IFFT unit <NUM>, an output is filtered and by filter <NUM>, a processor applies a power according to a power control procedure to power amplifier (PA) <NUM>, and a transmitted <NUM> transmits 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 are omitted.

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

<FIG> illustrates 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 in <FIG> is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure.

A received signal <NUM> is filtered by filter <NUM>, a fast Fourier transform (FFT) is applied by FFT unit <NUM>, a selector unit <NUM> selects REs <NUM> used by a transmitter, an inverse DFT (IDFT) unit applies an IDFT <NUM>, a demodulator <NUM> demodulates the IDFT output using a channel estimate provided by a channel estimator (not shown), and a controller (e.g., controller/processor <NUM> of <FIG>) selects a first decoder <NUM>, for example using tail-biting convolutional decoding or turbo decoding and CRC bits are extracted from each decoded codeword, or a second decoder <NUM>, for example using RM decoding. For example, the controller selects the TBCC decoder when an expected HARQ-ACK payload is larger than a predetermined value, such as <NUM> bits, and the controller selects the RM decoder when an expected HARQ-ACK payload is not larger than a predetermined value. UCI bits <NUM> are obtained by an output of either the first decoder or the second decoder. Additional receiver circuitry such as an analog-to-digital converter, filters, and channel estimator, are not shown for brevity.

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

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 <NUM> lists indicative UL/DL configurations over a period of <NUM> 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 <NUM>).

In a TDD system, a HARQ-ACK signal transmission from UE <NUM> in response to PDSCH receptions in multiple DL SFs can be transmitted in a same UL SF. A number Mw of DL SFs having associated HARQ-ACK signal transmissions from UE <NUM> in a same UL SF is referred to as a DL association set or as a bundling window of size Mw. A DL DCI format includes a DL assignment index (DAI) field of two binary elements (bits) that provides a counter indicating a number of DL DCI formats, modulo <NUM>, transmitted to UE <NUM> in a bundling window up to the SF of the DL DCI format detection. Table <NUM> indicates DL SFs n-k, where k∈K, that UE <NUM> transmits an associated HARQ-ACK signal in UL SF n. These DL SFs represent a bundling window for a respective UL SF.

A transmission power for a PUSCH is determined so that a PUSCH transmission from UE <NUM> is received with a desired SINR at eNB <NUM> while controlling a respective interference to neighboring cells thereby achieving a BLER target for data TBs in the PUSCH and ensuring proper network operation. UL power control (PC) includes open-loop PC (OLPC) with cell-specific and UE-specific parameters and closed-loop PC (CLPC) corrections provided to a UE by an eNB through transmission PC (TPC) commands. When a PUSCH transmission is scheduled by a PDCCH, a TPC command is included in a respective DCI format (see also REF <NUM>). TPC commands can also be provided by a separate PDCCH conveying a DCI format <NUM> or a DCI format 3A, for brevity jointly referred to as DCI format <NUM>/3A, providing TPC commands to a group of UEs (see also REF <NUM>). A DCI format includes cyclic redundancy check (CRC) bits and UE <NUM> identifies a DCI format type from a respective radio network temporary identifier (RNTI) used to scramble the CRC bits. For DCI format <NUM>/3A, a RNTI is a TPC-RNTI that UE <NUM> is configured by eNB <NUM> through higher layer signaling, such as radio resource control (RRC) signaling. For a DCI format scheduling a PUSCH transmission from UE <NUM> or a PDSCH transmission to UE <NUM>, a RNTI is a Cell RNTI (C-RNTI). Additional RNTI types also exist (see also REF <NUM>).

UE <NUM> can derive a PUSCH transmission power PPUSCH,c(i), in decibels per milliwatt (dBm), in cell c and SF i as in Equation <NUM>. For simplicity, it is assumed that UE <NUM> does not transmit both PUSCH and PUCCH in a same SF (see also REF <NUM>). <MAT> where,.

A PUCCH transmission power PPUCCH,c(i) from UE <NUM> in cell c and SF i is given by Equation <NUM> (see also REF <NUM>) <MAT> where.

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, Carrier Aggregation (CA) can be used as in REF <NUM> and scheduling decisions can be made by a same eNB <NUM> and conveyed to each network node. Moreover, UCI from UE <NUM> can be received at any network node, except possibly for nodes using unlicensed spectrum, and conveyed to eNB <NUM> to facilitate a proper scheduling decision for UE <NUM>.

<FIG> illustrates a communication using CA according to this disclosure.

UE <NUM><NUM>, communicates with a first cell <NUM> corresponding to a macro-cell using a first carrier frequency f1 <NUM> and with a second cell <NUM> corresponding to a small cell over carrier frequency f2 <NUM>. 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 eNB <NUM> and are connected over a backhaul that introduces negligible latency.

When UE <NUM> is configured with CA operation with up to <NUM> DL cells, HARQ-ACK transmission on a PUCCH typically uses a PUCCH format <NUM> (see also REF <NUM> and REF <NUM>). In a FDD system, a method for UE <NUM> to obtain a TPC command to adjust a power of a PUCCH format <NUM> transmission is from a TPC command field in a DCI format scheduling a PDSCH transmission on a primary cell (see also REF <NUM> and REF <NUM>). A method for UE <NUM> to determine a resource to transmit the PUCCH format <NUM> is from a TPC command field in a DCI format scheduling a PDSCH transmission on a secondary cell (see also REF <NUM>). Then, the TPC command field provides an acknowledgement resource indication (ARI) or, equivalently, a PUCCH resource index for one of four PUCCH resources configured to UE <NUM> by higher layers (see also REF <NUM>). For example, for a TPC command field of <NUM> bits and UE <NUM> configured with <NUM> resources for PUCCH format <NUM> transmission, an ARI can indicate one of the <NUM> resources (see also REF <NUM>).

For a TDD system, UE <NUM> uses a PUCCH format <NUM> resource determined from a TPC command field in a DCI format with DAI value greater than '<NUM>' or with DAI value equal to '<NUM>' that is not the first DCI format that UE <NUM> detects within a bundling window. UE <NUM> assumes that a same PUCCH resource index value is transmitted in all DCI formats used to determine the PUCCH resource index value for a bundling window (see also REF <NUM>). A functionality of a TPC command field in a DCI format with DAI value equal to '<NUM>' that is the first DCI format UE <NUM> detects in a bundling window remains unchanged and provides a TPC command value for UE <NUM> to adjust a transmission power for the PUCCH format <NUM>. In this manner, a DAI field functions both as a counter of DL DCI formats transmitted to UE <NUM> within a bundling window and as an indicator whether a TPC command field in a DCI format provides a TPC command value or whether a TPC command field in a DCI format provides an indicator to one PUCCH resource from a set of PUCCH resources configured to UE <NUM> (ARI).

When a DCI format is conveyed by an EPDCCH, the 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 DCI format schedules PDSCH on a primary cell or is set to zero when the DCI format schedules PDSCH on a secondary cell (see also REF <NUM> and REF <NUM>). Therefore, regardless of whether a DCI format scheduling a PDSCH transmission is conveyed by a PDCCH or an EPDCCH, UE <NUM> cannot obtain a TPC command to transmit associated HARQ-ACK information in a PUCCH when UE <NUM> does not detect a DCI format scheduling a PDSCH transmission on a primary cell.

Typical CA operation supports up to <NUM> DL cells each with a maximum of <NUM> BW and, for UL/DL configuration <NUM> in TDD systems, for up to <NUM> DL cells (see also REF <NUM>). This limitation on the number of DL cells that UE <NUM> can support limits DL data rates due to a respective limitation in a total DL BW. With an availability of unlicensed spectrum where many <NUM> BW carriers can exist, a number of cells that can be configured to UE <NUM> can become significantly larger than <NUM>. Therefore, extending support for CA beyond <NUM> DL cells can allow for more efficient utilization of available spectrum and improve DL data rates and service experience for UE <NUM>. 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 <NUM>) and use TBCC or TC to encode UCI. Achieving a desired detection reliability of a HARQ-ACK codeword or, in general, of a UCI codeword can become more difficult as a respective payload increases and it can be beneficial to improve transmission power control for a respective PUCCH format and improve a detection performance for a TBCC decoder or a TC decoder.

Embodiments of this disclosure provide mechanisms to increase a probability that a UE obtains TPC commands for transmission of a PUCCH format conveying HARQ-ACK information. Embodiments of this disclosure also provide mechanisms for a base station to indicate and for a UE to determine a resource for a PUCCH format transmission. Embodiments of this disclosure additionally provide mechanisms for a UE to determine a power for a PUCCH transmission. Embodiments of this disclosure additionally provide mechanisms for a base station to improve a detection reliability of a TBCC encoded HARQ-ACK codeword by utilizing known values in the HARQ-ACK codeword.

In the following, for brevity, a SPS PDSCH transmission or a DCI format indicating SPS PDSCH release is not explicitly mentioned; UE <NUM> is always assumed to include HARQ-ACK information for SPS PDSCH transmission or for a DCI format indicating SPS PDSCH release (see also REF <NUM>). Further, unless explicitly otherwise mentioned, a DCI format is assumed to schedule a PDSCH transmission (or SPS PDSCH release) in a respective cell. Further, UE <NUM> is configured a group of cells for possible receptions of respective PDSCH transmissions for operation with carrier aggregation. Each cell in the group of cells is identified by a UE-specific cell index that eNB <NUM> can inform UE <NUM> through higher layer signaling. UE <NUM> is configured to transmit HARQ-ACK information in a same PUCCH in response to PDSCH receptions in any cells from the group of cells. For example, UE <NUM> can be configured with a group of C cells and respective cell indexes <NUM>,<NUM>,.

When UE <NUM> is configured a parameter by eNB <NUM>, unless otherwise noted, the configuration is by higher layer signaling, such as RRC signaling, while when a parameter is dynamically indicated to UE <NUM> by eNB <NUM>, the indication is by physical layer signaling such as by a DCI format transmitted in a PDCCH or EPDCCH. UE <NUM> can be configured with more than one UL cell for PUCCH transmission, 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. UE <NUM> is assumed to transmit a PUCCH on a primary cell. UE <NUM> can also be configured by eNB <NUM> to transmit PUCCH on a primary secondary cell. In such case, UE <NUM> transmits PUCCH on the primary for UCI corresponding to a first group of DL cells (CG1) and transmits PUCCH on the primary secondary cell for UCI corresponding to a second group of DL cells (CG2). Unless otherwise explicitly noted, the descriptions in this disclosure are with respect to one group of DL cells and can be replicated for another group of DL cells.

A first embodiment of this disclosure considers power adjustments and resource determination for transmission of HARQ-ACK information in a PUCCH. Unless explicitly otherwise mentioned, a DCI format is assumed to schedule a PDSCH transmission in a respective cell. For brevity, a SPS PDSCH transmission or a DCI format indicating SPS PDSCH release is not explicitly mentioned; UE <NUM> is always assumed to include HARQ-ACK information for SPS PDSCH transmission or for a DCI format indicating SPS PDSCH release.

UE <NUM> can determine a number of DCI formats with associated HARQ-ACK information in a same PUCCH transmission based on a counter DAI field and a total DAI field (see also in REF <NUM>). The counter DAI in a DCI format transmitted in a SF is an incremental counter (modulo <NUM>) of DCI formats up to the DCI format in the SF with associated HARQ-ACK information in a same PUCCH transmission. The total DAI in a DCI format transmitted in a SF is a total counter (modulo <NUM>) of DCI formats up to the SF with associated HARQ-ACK information in a same PUCCH transmission.

In a first example for a FDD system, a method for providing TPC commands to UE <NUM> for adjusting a power of a PUCCH format transmission can depend on a number of DCI formats transmitted to the UE in a SF.

In a first method, a process for determining a TPC command to adjust a power of a PUCCH format transmission and for determining a PUCCH resource for the PUCCH format transmission depends on a number of transmitted DCI formats by eNB <NUM> or identified DCI formats by UE <NUM>. For a FDD system, when eNB <NUM> transmits a first number of DCI formats scheduling respective PDSCH transmissions in a first number of cells to UE <NUM>, eNB <NUM> can use the TPC command field to provide a TPC command only in a DCI format for a primary cell and use the TPC command field in any DCI format for a respective secondary cell to provide an ARI for a PUCCH resource determination to UE <NUM>. When, through a total DAI field, UE <NUM> determines (but not necessarily detects) a first number of DCI formats for a first number of cells, UE <NUM> can use a TPC command field only in a DCI format for a primary cell to obtain TPC command for a PUCCH transmission conveying HARQ-ACK and use a TPC command field in any DCI format for a respective secondary cell to obtain ARI for a PUCCH resource determination. When eNB <NUM> transmits a second number of DCI formats for a second number of cells, eNB <NUM> can use a TPC command field in a DCI format for a primary cell and in one or more DCI formats for respective one or more secondary cells to provide a TPC command and use a TPC command field in remaining DCI formats for respective secondary cells to provide ARI for a PUCCH resource determination to UE <NUM>. When, through a total DAI field, UE <NUM> determines (but not necessarily detects) a second number of DCI formats for a second number of respective cells, UE <NUM> can use each respective TPC command field in a DCI format for a primary cell and in one or more DCI formats for respective secondary cells to obtain TPC command and use a TPC command field in each remaining DCI formats for respective secondary cells to obtain ARI for a PUCCH resource determination.

<FIG> illustrates a use of a TPC command field in a DCI format depending on a number of DCI formats an eNB transmits to a UE according to this disclosure.

The eNB <NUM> transmits to UE <NUM> a first number D<NUM> of DCI formats scheduling respective PDSCH transmissions in respective cells in a SF <NUM>. UE <NUM> determines transmission of a second number D<NUM> of DCI formats scheduling PDSCHs in respective cells in the SF <NUM>. In absence of operating errors (DCI format detection errors), D<NUM> =D<NUM>. The second number of DCI formats that UE <NUM> determines that eNB <NUM> transmits to UE <NUM> in the SF is not necessarily same as a number of DCI formats UE <NUM> detects in the SF as, based on a use of a total DAI field, UE <NUM> can determine transmission of DCI formats that UE <NUM> failed to detect. The eNB <NUM> examines whether D<NUM> is larger than a first predetermined number DR<NUM> of DCI formats <NUM>. UE <NUM> examines whether D<NUM> is larger than a second predetermined number DR<NUM> of DCI formats <NUM>. When D<NUM>>DR<NUM>, eNB <NUM> provides TPC command in the TPC command field of at least one DCI format for a secondary cell <NUM>. When D<NUM>>DR<NUM>, UE <NUM> processes as a TPC command a value of a TPC command field of at least one DCI format for a secondary cell <NUM>. When D<NUM>≤DR<NUM>, eNB <NUM> provides only ARI in the TPC command field of each DCI format for a secondary cell <NUM>. When D<NUM>≤DR<NUM>, UE <NUM> processes only as ARI a value of the TPC command field of each DCI format for a secondary cell <NUM>.

In a second method, a process for determining a TPC command to adjust a power of a PUCCH format transmission and for determining a PUCCH resource for the PUCCH format transmission depends on the associated PUCCH format. For example, when UE <NUM> uses a first PUCCH format to transmit HARQ-ACK information, such as a PUCCH format <NUM> with transmission in one PRB pair, UE <NUM> can obtain a TPC command for adjusting a transmission power for the first PUCCH format only from the TPC command field in a DCI format for the primary cell and obtain an ARI for determining a resource for the first PUCCH format transmission from the TPC command field for any DCI format for a respective secondary cell. When UE <NUM> uses a second PUCCH format to transmit HARQ-ACK information, such as a PUCCH format with a PUSCH-based structure, UE <NUM> can obtain a TPC command for adjusting a transmission power for the second PUCCH format from the TPC command field in a DCI format for the primary cell and from the TPC command filed in some DCI formats for respective secondary cells and obtain an ARI for determining a resource for the second PUCCH format transmissions from the TPC command field in other DCI formats for respective secondary cells. A corresponding functionality can apply for eNB <NUM>.

<FIG> illustrates a use a TPC command field in a DCI format according to a PUCCH format used by a UE to transmit HARQ-ACK information according to this disclosure.

UE <NUM> determines a PUCCH format to use for HARQ-ACK transmission <NUM>. For example, the PUCCH format can be PUCCH format <NUM> with transmission in one PRB pair, or a PUCCH format based on the PUSCH structure. UE <NUM> determines whether the PUCCH format is a first PUCCH format, such as PUCCH format <NUM> with transmission in one PRB pair <NUM>. When the PUCCH format is the first PUCCH format, UE <NUM> uses a first method to obtain a TPC command and ARI <NUM>. When the PUCCH format is a second PUCCH format, UE <NUM> uses a second method to obtain a TPC command and ARI <NUM>. Similar steps apply when UE <NUM> considers whether a determined number of DCI formats scheduling PDSCH transmissions in respective cells is larger than a first number and when so, UE <NUM> uses a first method to obtain a TPC command and ARI; otherwise, UE <NUM> uses a second method to obtain a TPC command and ARI.

Different UL power control processes can be associated with respective different PUCCH formats and a TPC command for a transmission of a PUCCH format can either apply to a respective UL PC process or be common for all UL power control processes.

In case TPC commands or ARI is provided by one or more DCI formats for respective one or more secondary cells, several approaches can apply for a selection of the one or more DCI formats.

In a first approach, DCI formats can alternate in providing TPC commands or ARI where an ordering can be in an ascending order of a cell index with a respective PDSCH transmission. For example, when four DCI formats schedule respective four PDSCH transmissions in cells with indexes c<NUM>, c<NUM>, c<NUM>, and c<NUM> where c<NUM> < c<NUM> < c<NUM> < c<NUM>, a TPC command field in DCI formats for cells with indexes c<NUM> and c<NUM> can provide TPC commands while a TPC command field in DCI formats scheduling PDSCH transmissions in cells with indexes c<NUM> and c<NUM> can provide ARI. The first approach can be beneficial when cell indexing is such that UE <NUM> can experience similar channel conditions in cells with successive indexes, such as for example a similar propagation loss, a similar interference, or a similar availability of cells for PDSCH transmissions. Then, by alternating cell indexes where a TPC command field in a respective DCI format provides an actual TPC command or an ARI, a likelihood that UE <NUM> can detect at least two DCI formats providing a TPC command and an ARI, respectively, can increase.

In a second approach, when NC DCI formats are transmitted by eNB <NUM> or determined by UE <NUM> for scheduling PDSCH transmissions in respective NC cells, a first number of DCI formats, such as for example the first <MAT> (or <MAT> ) DCI formats or the first <NUM> DCI formats, after the first DCI format, can provide ARI and remaining DCI formats, such as the last <MAT> (or <MAT> ) DCI formats or the NC-<NUM> DCI formats (when NC><NUM>), respectively, can provide TPC commands where ┌ ┐ is a ceiling function rounding a number to the smallest integer that is larger than the number and └ ┘ is a floor function rounding a number to the largest integer that is smaller than the number. Both approaches can be conditioned on a TPC command field in a DCI format for the primary cell to provide a TPC command (instead of ARI).

By using the second approach when a number of DCI formats (transmitted by eNB <NUM> and determined by UE <NUM>) is large, so that for example UE <NUM> uses a second PUCCH format associated with transmission of DCI formats for a large number of cells, even when UE <NUM> fails to detect some DCI formats, a probability that UE <NUM> fails to detect all DCI formats providing TPC commands or all DCI formats providing ARI can be sufficiently lower than a probability of incorrect HARQ-ACK detection. Moreover, any approach can be conditioned so that a DCI format for a primary cell provides a TPC command for the PUCCH format transmission. Therefore, the application of the first method or the second method can also be associated with a use of a first PUCCH format or of a second PUCCH format, respectively.

<FIG> illustrates a mechanism for providing a TPC command and an ARI for a PUCCH transmission conveying HARQ-ACK information according to this disclosure.

UE <NUM> configured for CA operation detects first one or more DCI formats that schedule respective PDSCH transmissions in a first set of cells and second one or more DCI formats that schedule respective PDSCH transmissions in a second set of cells <NUM>. UE <NUM> determines a TPC command from TPC command field in the first one or more DCI formats and an ARI from a TPC command field in the second one or more DCI formats <NUM>. UE <NUM> transmits a PUCCH format conveying HARQ-ACK information by using the TPC command to adjust a transmission power and the ARI to determine a PUCCH resource <NUM>. Similar, eNB <NUM> transmits third one or more DCI formats that schedule PDSCH in a first set of cells and fourth one or more DCI format that schedule PDSCH in a second set of cells. The eNB <NUM> provides TPC command in the TPC command field in the first one or more DCI formats and ARI in the TPC command field in the second one or more DCI formats. The first one or more DCI formats or the third one or more DCI formats include at least one DCI format scheduling a respective at least one PDSCH transmission in respective at least one secondary cell.

In a second example, a TPC command field can always be used to provide TPC commands and an additional field can be included to provide ARI. For DCI formats transmitted by PDCCH, this additional field needs to be introduced as a new field. For DCI formats transmitted by EPDCCH, this additional field can be the HRO field when a DCI format schedules a PDSCH transmission in a secondary cell. Then, instead of the HRO field value being set to zero as for conventional operation (see also REF <NUM>), the HRO field is used as an ARI field.

Any of the two examples can also apply for a TDD system with an additional condition that applicability extends in every SF of a bundling window where eNB <NUM> transmits DCI formats to UE <NUM>. For the first method, in order to account for a likelihood that UE <NUM> experiences correlated channel conditions in SFs of a same bundling window and a likelihood that UE <NUM> is scheduled PDSCH transmissions in a same cell in multiple SFs of a same bundling window, a DCI format association for a TPC command field to a TPC command or to an ARI can alternate between successive SFs of a same bundling window. A primary cell can be excluded from this alternate association. For example, for the first approach, a TPC command field in a first, third, fifth, and so on, DCI formats can provide a TPC command and a TPC command field in a second, fourth, sixth, and so on DCI formats can provide an ARI in a first SF and the association can be reversed in a second SF of a same bundling window. Moreover, UE <NUM> can accumulate TPC commands in SFs of a bundling window having a number of Mw SFs. When δPUCCH(j) is a TPC command value in DCI formats for applicable cells in SF j, j = <NUM>, <NUM>,. , Mw-<NUM>, UE <NUM> can compute a final TPC command for adjusting a PUCCH transmission power as <MAT>. This can provide more accurate power control, particularly in association with a PUCCH format used for transmission of large HARQ-ACK payloads.

For a TDD system, the eNB <NUM> scheduler cannot be generally assumed to be capable of predicting scheduling decisions for PDSCH transmissions to UE <NUM> in future SFs of a same bundling window. Consequently, when UE <NUM> selects a PUCCH format according to a respective HARQ-ACK information payload, the eNB <NUM> scheduler cannot be generally assumed to know the PUCCH format at the first SF of the bundling window because the eNB <NUM> scheduler cannot know, in general, the HARQ-ACK information payload after the last SF of the bundling window. For example, when eNB <NUM> schedules PDSCH transmissions to UE <NUM> only in the first SF of a bundling window, UE <NUM> uses a first PUCCH format such as PUCCH format <NUM>, while when <NUM> eNB schedules PDSCH transmissions to UE <NUM> in all SFs of the bundling window, UE <NUM> uses a second PUCCH format such as a PUCCH format having a PUSCH-based structure, for example as in <FIG>. For a FDD system, unlike a TDD system, an eNB <NUM> scheduler knows a number of cells with PDSCH transmissions in a SF and can set an ARI value to either indicate a resource for a PUCCH format <NUM> when a corresponding HARQ-ACK payload is OHARQ-ACK ≤ <NUM> bits or indicate a resource for a PUSCH-based PUCCH format when a corresponding HARQ-ACK payload is OHARQ-ACK > <NUM> bits.

In order to enable eNB <NUM> and UE <NUM> to have a same understanding of a PUCCH resource for a transmission of a PUCCH format, an ARI value in a DCI format transmitted in a SF of a bundling window can indicate a resource for a PUCCH format that UE <NUM> would use in response to PDSCH receptions in previous SFs, when any, of the bundling window and in the SF of the bundling window. Therefore, the ARI value can depend on the SF of a respective DCI format transmission and can be different in DCI formats transmitted in different SFs of a bundling window. For example, a DCI format scheduling a PDSCH transmission in a first SF of a bundling window indicates (through a value of a TPC command field when it serves as an ARI field) a PUCCH resource for a first PUCCH format, such as PUCCH format <NUM>, while a DCI format scheduling a PDSCH transmission in a last SF of the bundling window indicates a PUCCH resource for a second PUCCH format, such as a PUCCH format <NUM> having a PUSCH-based structure.

<FIG> illustrates a determination by an eNB and by a UE of a PUCCH resource indicated by an ARI value in a DCI format transmitted in a SF of a bundling window according to this disclosure.

In a SF, eNB <NUM> (or UE <NUM>) determines a HARQ-ACK information payload based on transmitted DCI formats in SFs of a bundling window up to the SF <NUM>. The eNB <NUM> (or UE <NUM>) determines whether the HARQ-ACK information payload is associated with use of a first PUCCH format or of a second PUCCH format <NUM>. When the first PUCCH format is used, an ARI value in a DCI format transmitted in SF <NUM> indicates a resource for the first PUCCH format transmission <NUM>. When the second PUCCH format is used, the ARI value in the DCI format transmitted in SF <NUM> indicates a resource for the second PUCCH format transmission <NUM>.

When UE <NUM> transmits PUCCH on the primary cell for UCI corresponding to a first group of DL cells and transmits PUCCH on a primary secondary cell for UCI corresponding to a second group of DL cells, the first embodiment separately applies for the first group of DL cells and the primary cell and for the second group of DL cells and the primary secondary cell.

A second embodiment of this disclosure considers a power control mechanism for a PUCCH transmission. Unlike PUCCH formats supported for CA with up to <NUM> DL cells (see also REF <NUM> and REF <NUM>) where PUCCH transmission is always over one PRB pair, PUCCH transmission for CA with more than <NUM> DL cells can be in more than one PRB pair.

For HARQ-ACK transmission in a PUCCH, UE <NUM> can derive a PUCCH transmission power PPUCCH,c(i), in decibels per milliwatt (dBm), in cell c (primary cell or primary secondary cell) and SF i as in Equation <NUM>. <MAT> or equivalently, using a ΔF_PUCCH(F) offset relative to PUCCH format 1a as in Equation <NUM> for a PUCCH transmission power, as in Equation 3a <MAT> where,.

A third embodiment of this disclosure considers a detection procedure of a HARQ-ACK information codeword at eNB <NUM> when UE <NUM> encodes the HARQ-ACK codeword using TBCC.

An HARQ-ACK information codeword can include HARQ-ACK values that are known to eNB <NUM>. For example, when a cell-domain total DAI is not used to indicate cells with PDSCH transmissions to UE <NUM> from eNB <NUM> in a FDD system for determining an HARQ-ACK payload, UE <NUM> can include HARQ-ACK information for all configured cells in a HARQ-ACK information codeword. For cells where eNB <NUM> does not transmit a PDSCH to UE <NUM>, eNB <NUM> can expect that a respective HARQ-ACK value in the HARQ-ACK information codeword is a NACK/DTX value. For example, for a TDD system, when UE <NUM> provides HARQ-ACK information for PDSCH transmissions in a cell for every SF in a bundling window, eNB <NUM> can expect that in a SF where eNB <NUM> does not transmit PDSCH to UE <NUM>, a respective HARQ-ACK value in the HARQ-ACK information codeword is a NACK/DTX value. A NACK/DTX value can be represented, for example, by a binary '<NUM>' while an ACK value can be represented by a binary '<NUM>'.

When UE <NUM> uses TBCC for a HARQ-ACK information codeword, a TBCC decoder at eNB <NUM> can maintain a number of paths through a trellis where the paths can be selected according to respective likelihood metrics. A path with a largest likelihood metric can be discarded (respective branch in a trellis is pruned) when a resulting HARQ-ACK information codeword contains different values for HARQ-ACK information that is known in advance to eNB <NUM>, the path with the next largest likelihood metric can be selected, and so on, until a resulting decoded HARQ-ACK information codeword contains same values for HARQ-ACK information as the ones that are known in advance to eNB <NUM>. For example, considering for simplicity a HARQ-ACK information codeword of <NUM> bits (although in practice convolutional encoding applies to HARQ-ACK codewords of significantly larger size, such as above <NUM> bits), where eNB <NUM> expects a fourth bit to have a value of '<NUM>', eNB <NUM> can discard a decoded codeword of 'x1, x2, x3, <NUM>, x5' even when this codeword has a largest likelihood metric and instead select a codeword of 'y1, y2, y3, <NUM>, y5' that has a largest likelihood metric among codewords having a '<NUM>' binary value for their fourth element.

<FIG> illustrates a decoding process at an eNB for a TBCC encoded HARQ-ACK information codeword according to this disclosure.

The eNB <NUM> determines known values in a received, TBCC encoded, HARQ-ACK codeword <NUM> that is transmitted by UE <NUM> in response to receptions of PDSCH transmissions. For example, a known value can be a binary '<NUM>' at a position corresponding to a cell where eNB <NUM> does not transmit PDSCH in a SF. A TBCC decoder at eNB <NUM> decodes the TBCC encoded HARQ-ACK codeword and maintains a number of paths through a decoding trellis and respective likelihood metrics <NUM>. The number of paths can depend on the eNB <NUM> decoder implementation. The eNB <NUM> determines whether or not a HARQ-ACK codeword corresponding to a path with a largest metric is verified <NUM>. Verification can be by determining whether or not the known values for a candidate HARQ-ACK codeword corresponding to the path with the largest metric are same with the values of the decoded HARQ-ACK codeword at respective predetermined locations that can correspond, for example, to cell indexes. When verification is positive, eNB <NUM> can select the candidate HARQ-ACK codeword as the one corresponding to the path with the largest metric <NUM>. When verification is negative, eNB <NUM> can discard a current path with a largest metric from the number of paths <NUM> and then repeat step <NUM>. Equivalently, the eNB <NUM> TBCC decoder can prune branches in the trellis that correspond to a different HARQ-ACK information bit value than a known HARQ-ACK information bit value at a respective position in the HARQ-ACK codeword.

<FIG> illustrates a path selection by a decoder using knowledge of known bits in a codeword according to this disclosure.

Claim 1:
A user equipment, UE (<NUM>), in a communication system, the UE (<NUM>) comprising:
a transceiver (<NUM>); and
a controller (<NUM>) coupled with the transceiver and configured to:
receive a number of physical downlink control channels, PDCCHs, that include downlink control information, DCI, formats scheduling receptions of physical downlink shared channels, PDSCHs, that include transport blocks, TBs, and
transmit a physical uplink control channel, PUCCH, that includes a number of hybrid automatic repeat request acknowledgement, HARQ-ACK, information bits in response to the receptions of the TBs in the PDSCHs on a PUCCH resource, characterized in that
wherein the PUCCH resource is determined from a field in a last DCI format among the DCI formats being ordered,
wherein the field in the last DCI format indicates the PUCCH resource from a set of PUCCH resources determined based on the number of HARQ-ACK information bits.