Hybrid automatic repeat request-acknowledge (HARQ-ACK) codebook generation for inter-band time division duplex (TDD) carrier aggregation (CA)

Technology to determine a Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook size for inter-band time division duplex (TDD) carrier aggregation (CA) is disclosed. In an example, a user equipment (UE) operable to determine a HARQ-ACK codebook size for inter-band TDD CA can include computer circuitry configured to: Determine a HARQ bundling window for inter-band TDD CA including a number of downlink (DL) subframes using HARQ-ACK feedback; divide the HARQ bundling window into a first part and a second part; and calculate the HARQ-ACK codebook size based on the first part and the second part. The first part can include DL subframes of configured serving cells that occur no later than the DL subframe where a downlink control information (DCI) transmission for uplink scheduling on a serving cell is conveyed, and the second part can include physical downlink shared channel (PDSCH) subframes occurring after the DCI transmission of the serving cells.

BACKGROUND

Wireless mobile communication technology uses various standards and protocols to transmit data between a node (e.g., a transmission station) and a wireless device (e.g., a mobile device). Some wireless devices communicate using orthogonal frequency-division multiple access (OFDMA) in a downlink (DL) transmission and single carrier frequency division multiple access (SC-FDMA) in an uplink (UL) transmission. Standards and protoCols that use orthogonal frequency-division multiplexing (OFDM) for signal transmission include the third generation partnership project (3GPP) long term evolution (LTE), the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard (e.g., 802.16 e, 802.16 m), which is commonly known to industry groups as WiMAX (Worldwide interoperability for Microwave Access), and the IEEE 802.11 standard, which is commonly known to industry groups as WiFi.

In 3GPP radio access network (RAN) LTE systems, the node can be a combination of Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node Bs (also commonly denoted as evolved Node Bs, enhanced Node Bs, eNodeBs, or eNBs) and Radio Network Controllers (RNCs), which communicates with the wireless device, known as a user equipment (UE). The downlink (DL) transmission can be a communication from the node (e.g., eNodeB) to the wireless device (e.g., UE), and the uplink (UL) transmission can be a communication from the wireless device to the node.

In LTE, data can be transmitted from the eNodeB to the UE via a physical downlink shared channel (PDSCH). A physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) can be used to acknowledge that data was received. Downlink and uplink channels or transmissions can use time-division duplexing (TDD) or frequency-division duplexing (FDD). Time-division duplexing (TDD) is an application of time-division multiplexing (TDM) to separate downlink and uplink signals. In TDD, downlink signals and uplink signals may be carried on a same carrier frequency (i.e., shared carrier frequency) where the downlink signals use a different time interval from the uplink signals, so the downlink signals and the uplink signals do not generate interference for each other. TDM is a type of digital multiplexing in which two or more bit streams or signals, such as a downlink or uplink, are transferred apparently simultaneously as sub-channels in one communication channel, but are physically transmitted on different resources. In frequency-division duplexing (FDD), an uplink transmission and a downlink transmission can operate using different frequency carriers (i.e. separate carrier frequency for each transmission direction). In FDD, interference can be avoided because the downlink signals use a different frequency carrier from the uplink signals.

DETAILED DESCRIPTION

All tables cited herein from the 3GPP LTE standard are provided from Release 11 of the 3GPP LTE standard, unless otherwise noted.

Example Embodiments

An increase in the amount of wireless data transmission has created congestion in wireless networks using licensed spectrum to provide wireless communication services for wireless devices, such as smart phones and tablet devices. The congestion is especially apparent in high density and high use locations such as urban locations and universities.

One technique for providing additional bandwidth capacity to wireless devices is through the use carrier aggregation of multiple smaller bandwidths to form a virtual wideband channel at a wireless device (e.g., UE). In carrier aggregation (CA) multiple component carriers (CC) can be aggregated and jointly used for transmission to/from a single terminal. Carriers can be signals in permitted frequency domains onto which information is placed. The amount of information that can be placed on a carrier can be determined by the aggregated carrier's bandwidth in the frequency domain. The permitted frequency domains are often limited in bandwidth. The bandwidth limitations can become more severe when a large number of users are simultaneously using the bandwidth in the permitted frequency domains.

FIG. 1illustrates a carrier bandwidth, signal bandwidth, or a component carrier (CC) that can be used by the wireless device. For example, the LTE CC bandwidths can include: 1.4 MHz210, 3 MHz212, 5 MHz214, 10 MHz216, 15 MHz218, and 20 MHz220. The 1.4 MHz CC can include 6 resource blocks (RBs) comprising 72 subcarriers. The 3 MHz. CC can include 15 RBs comprising 180 subcarriers. The 5 MHz CC can include 25 RBs comprising 300 subcarriers. The 10 MHz CC can include 50 RBs comprising 600 subcarriers. The 15 MHz CC can include 75 RBs comprising 900 subcarriers. The 20 MHz CC can include 100 RBs comprising 1200 subcarriers.

Carrier aggregation (CA) enables multiple carrier signals to be simultaneously communicated between a user's wireless device and a node. Multiple different carriers can be used. In some instances, the carriers may be from different permitted frequency domains. Carrier aggregation provides a broader choice to the wireless devices, enabling more bandwidth to be obtained. The greater bandwidth can be used to communicate bandwidth intensive operations, such as streaming video or communicating large data files.

FIG. 2Aillustrates an example of carrier aggregation of continuous carriers. In the example, three carriers are contiguously located along a frequency band. Each carrier can be referred to as a component carrier. In a continuous type of system, the component carriers are located adjacent one another and can be typically located within a single frequency band (e.g., band A). A frequency band can be a selected frequency range in the electromagnetic spectrum. Selected frequency bands are designated for use with wireless communications such as wireless telephony. Certain frequency bands are owned or leased by a wireless service provider. Each adjacent component carrier may have the same bandwidth, or different bandwidths. A bandwidth is a selected portion of the frequency band. Wireless telephony has traditionally been conducted within a single frequency band. In contiguous carrier aggregation, only one fast Fourier transform (FFT) module and/or one radio frontend may be used. The contiguous component carriers can have similar propagation characteristics which can utilize similar reports and/or processing modules.

FIGS. 2B-2Cillustrates an example of carrier aggregation of non-continuous component carriers. The non-continuous component carriers may be separated along the frequency range. Each component carrier may even be located in different frequency bands. Non-contiguous carrier aggregation can provide aggregation of a fragmented spectrum. Intra-band (or single-band) non-contiguous carrier aggregation provides non-contiguous carrier aggregation within a same frequency band (e.g., band A), as illustrated inFIG. 2B. Inter-band (or multi-band) non-contiguous carrier aggregation provides non-contiguous carrier aggregation within different frequency bands (e.g., bands A, B, or C), as illustrated inFIG. 2C. The ability to use component carriers in different frequency bands can enable more efficient use of available bandwidth and increases the aggregated data throughput.

Network symmetric (or asymmetric) carrier aggregation can be defined by a number of downlink (DL) and uplink (UL) component carriers offered by a network in a sector. UE symmetric (or asymmetric) carrier aggregation can be defined by a number of downlink (DL) and uplink (UL) component carriers configured for a UE. The number of DL CCs may be at least the number of UL CCs. A system information block type2(SIB2) can provide specific linking between the DL and the UL.FIG. 3Aillustrates a block diagram of a symmetric-asymmetric carrier aggregation configuration, where the carrier aggregation is symmetric between the DL and UL for the network and asymmetric between the DL and UL for the UE.FIG. 3Billustrates a block diagram of an asymmetric-symmetric carrier aggregation configuration, where the carrier aggregation is asymmetric between the DL and UL for the network and symmetric between the DL and UL for the UE.

For each UE, a CC can be defined as a primary cell (PCell). Different UEs may not necessarily use a same CC as their PCell. The PCell can be regarded as an anchor carrier for the UE and the PCell can thus be used for control signaling functionalities, such as radio link failure monitoring, hybrid automatic repeat request-acknowledgement (HARQ-ACK), and PUCCH resource allocations (RA). If more than one CC is configured for a UE, the additional CCs can be denoted as secondary cells (SCells) for the UE.

A component carrier can be used to carry channel information via a radio frame structure transmitted on the physical (PHY) layer in a downlink transmission between a node (e.g., eNodeB) and the wireless device (e.g., UE) using a generic long term evolution (LTE) frame structure, as illustrated inFIG. 4. In another example, a component carrier can be used to carry channel information via a radio frame structure transmitted on the PHY layer in a uplink transmission between a node (e.g., eNodeB) and the wireless device (e.g., UE) using a generic long term evolution (LTE) frame structure, as illustrated inFIG. 5. While an LTE frame structure is illustrated, a frame structure for an IEEE 802.16 standard (WiMax), an IEEE 802.11 standard (WiFi), or another type of communication standard using SC-FDMA or OFDMA may also be used.

FIG. 4illustrates a downlink radio frame structure type2. In the example, a radio frame400of a signal used to transmit the data can be configured to have a duration, Tf, of 10 milliseconds (ms). Each radio frame can be segmented or divided into ten subframes410ithat are each 1 ms long. Each subframe can be further subdivided into two slots420aand420b, each with a duration, Tslot, of 0.5 ms. The first slot (#0)420acan include a legacy physical downlink control channel (PDCCH)160and/or a physical downlink shared channel (PDSCH)466, and the second slot (#1)420bcan include data transmitted using the PDSCH.

Each slot for a component carrier (CC) used by the node and the wireless device can include multiple resource blocks (RBs)430a,430b,430i,430m, and430nbased on the CC frequency bandwidth. The CC can have a carrier frequency having a bandwidth and center frequency. Each subframe of the CC can include downlink control information (DCI) found in the legacy PDCCH. The legacy PDCCH in the control region can include one to three columns of the first OFDM symbols in each subframe or RB, when a legacy PDCCH is used. The remaining 11 to 13 OFDM symbols (or 14 OFDM symbols, when legacy PDCCH is not used) in the subframe may be allocated to the PDSCH for data (for short or normal cyclic prefix).

The control region can include physical control format indicator channel (PCFICH), physical hybrid automatic repeat request (hybrid-ARQ) indicator channel (PHICH), and the PDCCH. The control region has a flexible control design to avoid unnecessary overhead. The number of OFDM symbols in the control region used for the PDCCH can be determined by the control channel format indicator (CFI) transmitted in the physical control format indicator channel (PCFICH). The PCFICH can be located in the first OFDM symbol of each subframe. The PCFICH and PHICH can have priority over the PDCCH, so the PCFICH and PHICH are scheduled prior to the PDCCH.

Each RB (physical RB or PRB)430ican include 12-15 kHz subcarriers436(on the frequency axis) and 6 or 7 orthogonal frequency-division multiplexing (OFDM) symbols432(on the time axis) per slot. The RB can use seven OFDM symbols if a short or normal cyclic prefix (CP) is employed. The RB can use six OFDM symbols if an extended cyclic prefix (CP) is used. The resource block can be mapped to 84 resource elements (REs)440iusing short or normal cyclic prefixing, or the resource block can be mapped to 72 REs (not shown) using extended cyclic prefixing. The RE can be a unit of one OFDM symbol442by one subcarrier (i.e., 15 kHz)446.

Each RE can transmit two bits450aand450bof information in the case of quadrature phase-shift keying (QPSK) modulation. Other types of modulation may be used, such as 16 quadrature amplitude modulation (QAM) or 64 QAM to transmit a greater number of bits in each RE, or bi-phase shift keying (BPSK) modulation to transmit a lesser number of bits (a single bit) in each RE. The RB can be configured for a downlink transmission from the eNodeB to the UE, or the RB can be configured for an uplink transmission from the UE to the eNodeB.

Communication of data on a physical downlink shared channel (PDSCH) can be controlled via a control channel, referred to as a physical downlink control channel (PDCCH). The PDCCH can be used for downlink (DL) and uplink (UL) resource assignments (e.g., UL grants), transmit power commands, and paging indicators. The data carried on the PDCCH can be referred to as downlink control information (DCI).

The DCI has various formats to define resource allocations. For example in LTE, DCI format0can be used for the transmission of uplink shared channel (UL-SCH) allocation or assignments (e.g., UL grants), which can be used for scheduling of PUSCH and transmit power control (TPC) command for UL power control. DCI format1can be used for the transmission of downlink shared channel (DL-SCH) assignments for single antenna operation, which can transmit PDSCH for single-input multiple-output (SIMO) operation. DCI format1A can be used for a compact transmission of DL-SCH assignments for single antenna (e.g., SIMO) operation, allocation for SIMO operation or allocating a dedicated preample signature to a UE for random access, or UL power control. DCI format1B can be used for compact scheduling or resource assignment with precoding information to support multiple-input multiple-output (MIMO) closed-loop (CL) single-rank transmission with possibly contiguous resource allocation. DCI format1C can be for very compact scheduling of resource allocation for PDSCH to support downlink transmission of paging, random access channel (RACH) response, and dynamic broadcast control channel (BCCH) scheduling. DCI format1C can be similar to DCI format1B with additional power offset information. DCI format2can be for compact DL-SCH allocation and scheduling with precoding and power offset information used to support the transmission of DL-SCH assignments for MIMO operation, which can be used for CL DL MIMO and UL power control. DCI format2A can be for compact DL-SCH allocation and scheduling with precoding and power offset information used to support the transmission of DL-SCH assignments for MIMO operation, which can be used for open loop (OL) DL MIMO and UL power control. DCI formats2C and2D can also be used for the transmission of DL-SCH assignments for MIMO operations. DCI format3can be used for the transmission of TPC commands for an uplink channel (e.g., PUCCH and PUSCH) with 2-bit power adjustments (for multiple UEs). DCI format3A can be used for the transmission of TPC commands for an uplink channel (e.g., PUCCH and PUSCH) with single bit power adjustments (for multiple UEs). DCI formats used to grant PUSCH transmissions can be provided by DCI format0and DCI format4, which can also be referred to as uplink DCI formats when common behavior is addressed.

The various scenarios for the downlink can also be reflected in different transmission modes (TMs). For example, in LTE, TM1can use a single transmit antenna; TM2can use transmit diversity; TM3can use open loop spatial multiplexing with cyclic delay diversity (CDD); TM4can use closed loop spatial multiplexing; TM5can use multi-user MIMO (MU-MIMO); TM6can use closed loop spatial multiplexing using a single transmission layer; TM7can use beamforming with UE-specific RS; TM8can use single or dual-layer beamforming with UE-specific RS; and TM9can use a multilayer transmission to support closed-loop single user MIMO (SU-MIMO) or carrier aggregation. In an example, TM10can be used for coordinated multipoint (CoMP) signaling, such as joint processing (JP), dynamic point selection (DPS), and/or coordinated scheduling/coordinated beamforming (CS/CB).

FIG. 5illustrates an uplink radio frame structure. A similar structure can be used for a downlink radio frame structure using OFDMA (as shown inFIG. 4). In the example, a radio frame100of a signal used to transmit control information or data can be configured to have a duration, Tf, of 10 milliseconds (ms). Each radio frame can be segmented or divided into ten subframes110ithat are each 1 ms long. Each subframe can be further subdivided into two slots120aand120b, each with a duration, Tslot, of 0.5 ms. Each slot for a component carrier (CC) used by the wireless device and the node can include multiple resource blocks (RBs)130a,130b,130i,130m, and130nbased on the CC frequency bandwidth. Each RB (physical RB or PRB)130ican include 12-15 kHz subcarriers136(on the frequency axis) and 6 or 7 SC-FDMA symbols132(on the time axis) per subcarrier. The RB can use seven SC-FDMA symbols if a short or normal cyclic prefix is employed. The RB can use six SC-FDMA symbols if an extended cyclic prefix is used. The resource block can be mapped to 84 resource elements (REs)140iusing short or normal cyclic prefixing (CP), or the resource block can be mapped to 72 REs (not shown) using extended cyclic prefixing (CP). The RE can be a unit of one SC-FDMA symbol142by one subcarrier (i.e., 15 kHz)146. Each RE can transmit two bits150aand150bof information in the case of quadrature phase-shift keying (QPSK) modulation. Other types of modulation may be used, such as 16 quadrature amplitude modulation (QAM) or 64 QAM to transmit a greater number of bits in each RE, or bi-phase shift keying (BPSK) modulation to transmit a lesser number of bits (a single bit) in each RE. The RB can be configured for an uplink transmission from the wireless device to the node.

An uplink signal or channel can include data on a Physical Uplink Shared CHannel (PUSCH) or control information on a Physical Uplink Control CHannel (PUCCH). In LTE, the uplink physical channel (PUCCH) carrying uplink control information (UCI) can include channel state information (CSI) reports, Hybrid Automatic Repeat reQuest (HARQ) ACKnowledgment/Negative ACKnowledgment (ACK/NACK) and uplink scheduling requests (SR).

The wireless device (e.g., UE) can provide HARQ-ACK feedback for a PDSCH using a PUCCH. The PUCCH can support multiple formats (i.e., PUCCH format) with various modulation and coding schemes (MCS), as shown for LTE in Table 1. Similar information to Table 1 can be shown in 3GPP LTE standard Release 11 (e.g., V11.1.0 (2012-12)) Technical Specification (TS) 36.211 Table 5.4-1. For example, PUCCH format3can be used to convey a 48-bit HARQ-ACK, which can be used for carrier aggregation.

Legacy LTE TDD can support asymmetric UL-DL allocations by providing seven different semi-statically configured uplink-downlink configurations. Table 2 illustrates seven UL-DL configurations used in LTE, where “D” represents a downlink subframe, “S” represents a special subframe, and “U” represents an uplink subframe. In an example, the special subframe can operate or be treated as a downlink subframe. Similar information to Table 2 can be shown in 3GPP LTE TS 36.211 Table 4.2-2.

As illustrated by Table 2, UL-DL configuration0can include 6 uplink subframes in subframes2,3,4,7,8, and9, and4downlink and special subframes in subframes0,1,5, and6; and UL-DL configuration5can include one uplink subframe in subframe2, and9downlink and special subframes in subframes0,1, and3-9. Each uplink subframe n can be associated with a downlink subframe based on the uplink-downlink configuration, where each uplink subframe n can have a downlink association set index K ε{k0, k1, . . . kM-1} where M is defined as the number of elements in set K, as illustrated by Table 3. Similar information to Table 3 can be shown in 3GPP LTE TS 36.213 Table 10.1.3.1-1.

The Table 3 shows examples of downlink subframe bundling in an uplink subframe handling ACK/NACK feedback for certain downlink subframe(s). For example, in uplink-downlink configuration4, uplink subframe2(subframe n) handles ACK/NACK feedback for downlink and special subframes which are {12,8,7,11} subframes (subframes km) earlier than uplink subframe2(i.e., downlink and special subframes {0,4,5,1} (or downlink and special subframes n−km)) and M equals 4. Uplink subframe3(subframe n) handles ACK/NACK feedback for downlink subframes which are {6,5,4,7} subframes (subframes km) earlier than uplink subframe3(i.e., downlink subframes {7,8,9,6} (or downlink subframes n−km)) and M equals 4. For uplink-downlink configuration5uplink subframe2, M equals 9. For uplink-downlink configuration0, uplink subframe2, M equals one, and uplink subframe3, M equals zero. Depending on the uplink-downlink configuration one uplink subframe may be responsible for ACK/NACK feedback for one or multiple downlink subframes. In certain situations, even distribution between uplink subframe responsibility can be desired to reduce situations where one uplink subframe is responsible for ACK/NACK feedback for a large number of downlink and special subframes.

As an underlying requirement in some examples, cells of the network can change UL-DL (TDD) configurations synchronously in order to avoid the interference. However, such a requirement can constrain the traffic management capabilities in different cells of the network. The legacy LTE TDD set of configurations can provide DL subframe allocations in the range between 40% and 90%, as shown in Table 2. The UL and DL subframes allocation within a radio frame can be reconfigured through system information broadcast signaling (e.g., system information block [SIB]). Hence, the UL-DL allocation once configured can be expected to vary semi-statically.

A property of TDD is that a number of UL and DL subframes can be different as shown in Table 2 and often the number of DL subframes can be more than the number of UL subframes for a radio frame. In configurations where more DL subframes are used than UL subframes, multiple DL subframes can be associated with one single UL subframe for the transmission of a corresponding control signals. A configuration-specific HARQ-ACK timing relationship can be defined (e.g., 3GPP LTE standard Release 11 (e.g., V11.1.0 (2012-12)) TS 36.213 Table 10.1.3.1-1 or Table 3). If a UE is scheduled in a multiple of DL subframes, which can be associated with one UL subframe, the UE can transmit multiple ACK/NAK (ACK/NACK) bits in that UL subframe. A number of DL subframes with HARQ-ACK feedback on one single UL subframe can comprise one bundling window. In an example, HARQ-ACK bundling window may not be used for configuration5, with 9 DL subframes.

An advantage of a Time Division Duplex (TDD) system can be a flexible resource utilization through different TDD configurations to better match the uplink and downlink traffic characteristics of the cell. By configuring different TDD configurations, the ratio between available UpLink (UL) and Downlink (DL) resources can range from 3UL:2DL (6UL:4DL) to 1UL:9DL. In legacy LTE TDD (e.g., LTE Release 10 (Rel-10) specification), only the aggregation of TDD Component Carriers (CCs) of a same UL-DL configuration may be defined and supported. While the same UL-DL configuration can simplify a design and operation of CC, the same UL-DL configuration can also impose some limitations.

In an example, inter-band carrier aggregation (CA) for a TDD system with different uplink-downlink configurations on different bands can be supported. For instance, more than one TDD carrier can be deployed by a single TDD operator and the carriers can be aggregated at a single base station (e.g., node). Besides, a separation between two carrier frequencies can be large enough to avoid UL-DL interference from a same device. Some of the benefits of inter-band CA with different TDD configurations on different bands can be include (1) legacy system co-existence, (2) heterogeneous network (HetNet) support, (3) aggregation of traffic-dependent carriers, (4) flexible configuration (e,g., more UL subframe in lower bands for better coverage, and more DL subframes in higher bands), and (5) higher peak rate.

Supporting Inter-band TDD Carrier Aggregation (CA) with different uplink-downlink configurations can be used to aggregate component carriers (CC) with different DL/UL configurations. To provide high peak data rate enhancement benefits to both full- and half-duplex UEs, HARQ (Hybrid Automatic Repeat reQuest) ACK/NACK feedback for downlink (DL) data may use a PUCCH only transmitted on Primary Cell (PCell), use legacy HARQ-ACK timing for PCell PDSCH by following a PCell SIB type1(SIB1) UL-DL configuration, and use HARQ-ACK timing for the PDSCH of a Secondary Cell (SCell) following a specific reference UL-DL configuration (e.g., PCell and SCell UL-DL configuration) as shown in Table 4 illustrated inFIG. 6. For example, HARQ-ACK timing of the PDSCH on the PCell can follow the PCell SIB1legacy UL/DL configuration. For the PDSCH transmitted on the SCell, the HARQ timing can follow reference legacy UL/DL configuration as shown in Table 4.

Interband TDD CA with different UL-DL configurations in different bands can be supported. For example, an SCell PDSCH HARQ reference timing can be determined from a PCell UL-DL configuration and a SCell UL-DL configuration, as shown in Table 4 illustrated inFIG. 6. Table 4 (i.e.,FIG. 6) illustrates the UL-DL configuration number of PDSCH HARQ-ACK timing reference for SCell. A HARQ-ACK timing of PCell PDSCH, the scheduling timing of PCell PUSCH, the HARQ timing of PCell PUSCH can use the PCell SIB1configuration. A UE can be configured with PUCCH format3for HARQ-ACK transmission and self-carrier scheduling for TDD inter-band carrier aggregation (CA) with different UL-DL configurations on different bands.

In Time-Division Long-Term Evolution (TD-LTE) system (also referred to as LTE Time-Division Duplex (LTE TDD) system), the HARQ-Acknowledgement (HARQ-ACK) for downlink data can be either transmitted on PUCCH channel or piggybacked on uplink PUSCH data prior to discrete Fourier transform-spreading (DFTS) in order to preserve an uplink single-carrier low-cubic metric property. When HARQ-ACK is to be transmitted in a subframe in which the UE has been allocated transmission resources for the PUSCH, HARQ-ACK resources can be mapped to SC-FDMA symbols by puncturing the PUSCH data resource elements (RE). Such PUSCH puncturing can cause PUSCH performance degradation, especially when the puncture is excessive. Therefore, PUSCH performance can be improved, if PUSCH REs punctured by HARQ-ACK symbols is minimized. To reduce PUSCH REs puncturing by HARQ-ACK symbols, 2-bits Downlink Assignment Index (DAI) in downlink control information (DCI) format0/4, VDAIUL, can be used for TDD HARQ-ACK bundling or HARQ-ACK multiplexing to indicate the total number of DL assignments in a DL subframe bundling window. For example, assuming the bundling window size is M, as defined in Table 3, VDAIULHARQ-ACK bits, instead of M bits, can be fedback to eNB if a PUSCH transmission is adjusted based on a detected PDCCH with an uplink DCI format (e.g., DCI format0or4), so the un-needed (M−VDAIUL) HARQ-ACK bits corresponding to the un-scheduled DL subframes by eNB are consequently reduced. The value VDAIULcan include all PDSCH transmission with and without corresponding PDCCH within all the subframe(s) n−k, as defined in Table 3.

In coding theory, puncturing is the process of removing some of the parity bits after encoding with an error-correction code. Puncturing can have the same effect as encoding with an error-correction code with a higher rate (e.g., modulation and coding scheme (MCS)), or less redundancy. With puncturing a same decoder can be used regardless of how many bits have been punctured, thus puncturing can considerably increase the flexibility of a system without significantly increasing the system's complexity.

The DAI is a field in the downlink resource grant signaled to a UE, indicating how many subframes in a previous time window have contained transmissions to that UE. DAI can be applicable only when LTE is operated in TDD mode, and can enable the UE to determine whether the UE has received all the downlink transport blocks for which the UE transmits a combined ACK/NACK. For instance, the TDD configuration1with a dynamic 80-90% DL ratio can use a 2-bit DAI to indicate subframes3and8.

If carrier aggregation(CA) is configured for UE in a legacy TD-LTE system (e.g., LTE release 10), the HARQ-ACK codebook size (in a case of piggybacking on PUSCH) can be determined by a number of configured CCs, the CCs' configured transmission mode, and a number of downlink subframes in the bundled window. When TDD UL-DL configuration1-6is used and PUCCH format3is configured for transmission of the HARQ-ACK, the HARK-ACK codebook size in PUSCH can be represented by Equation 1:
nHARQ=BcDL(C+C2)  [Equation 1],

where C is the number of downlink CCs configured; C2is the number of downlink CCs with configured transmission mode enabling the reception of two transport blocks (TB) (if spatial bundling is not employed), otherwise C2=0; BcDLis the number of downlink subframes for which UE needs to feedback HARQ-ACK bits for the c-th serving cell, and c≧0.

For TDD UL-DL configuration1,2,3,4and6, the UE can assume that BcDLon PUSCH subframe n is represented by Equation 2. Equation 2 may not apply to UL-DL configurations0and5because UL-DL configuration0may not transmit a value WDAIUL, and UL-DL configuration5may not use a HARQ-ACK bundling window with 9 DL subframes (as previously discussed).
BcDL=WDAIUL[Equation 2],

where WDAIULis determined by the downlink assignment index (DAI) in an uplink DCI format (e.g., DCI format0/4) according to Table 6 in subframe n−k′, where k′ is defined in Table 5 for each serving cell. Similar information to Table 5 can be shown in 3GPP LTE TS 36.213 Table 7.3-Y. Similar information to Table 6 can be shown in 3GPP LTE TS 36.213 Table 7.3-Z.

As defined in a legacy LTE system, the uplink DCI format (e.g., DCI format0/4) for PUSCH scheduling can be transmitted in the last downlink subframe (subframe #3) within each bundling window, as shown inFIG. 7. When this occurs, the eNB can determine how many DL subframes have been transmitted within each serving cell c, so the eNB can directly set the value of WDAIULas a maximum number of BcDL, 0≦c<C for the configured CCs. Since WDAIULmay be no larger than the bundling window size in the legacy LTE system, HARQ-ACK codebook size determined by WDAIULin the uplink DCI format can be equal to a minimum HARQ-ACK bits number. Using WDAIULto determine the HARQ-ACK codebook size can be a good tradeoff between HARQ-ACK overhead and PUSCH performance.

FIG. 7depicts a location of downlink subframe containing the UL grant within an ithPDSCH bundling window (e.g., HARQ bundling window), where a previous downlink subframes9,0, and3, and special subframe1can comprise one bundling window on a PCell and SCell according a predefined HARQ-ACK timing relation for UL-DL configuration2for uplink subframe7. Subframe3of the PCell can include the UL grant for subframe7for the PCell and the SCell. In an example, the HARQ-ACK for the PDSCH of the ithPDSCH bundling window can be provided by a UCI in the PUSCH.

Inter-band TDD carrier aggregation (CA) with different uplink-downlink configurations can also be supported, where component carriers (CC) with different DL/UL configurations can be aggregated, as illustrated inFIGS. 8A-B. For example, in order to provide high peak data rate enhancement to both full- and half-duplex UEs, Hybrid Automatic Repeat reQuest (HARQ) ACK/NACK feedback for downlink (DL) data can have various constraints. For instance, the PUCCH may only transmitted on Primary Cell (PCell), the HARQ-ACK timing of the PCell PDSCH can follow the PCell's own SIB1UL-DL configuration, or for the PDSCH of SCell, the HARQ-ACK timing can follow a specific reference UL-DL configuration, such as Table 4 (FIG. 6).

According to the HARQ-ACK timing table (i.e., Table 4) for the SCell PDSCH (as shown inFIG. 6), the size of HARQ-ACK bundling window can be different between the PCell and the SCell. Based on this observation, if a UE configured with PUCCH format3for HARQ-ACK transmission, the HARQ-ACK transmission can follow a legacy design except for the following exception introducing Equation 3:

If the timing reference configuration is #{1,2,3,4,6}, for HARQ-ACK transmission in an UL subframe ‘n’ and on a PUSCH adjusted by an UL grant, the number of downlink subframes for which the UE can feedback HARQ-ACK bits for the c-th serving cell can be represented by Equation 3:
BcDL=min(WDAIUL,Mc)  [Equation 3],

where Mcrepresents the total number of subframes with PDSCH transmissions and with PDCCH indicating downlink semi-persistent scheduling (SPS) release to the corresponding UE within HARQ-ACK bundling window associated with UL subframe n for the c-th serving cell. Using the method implementing Equation 3 can effectively reduce the HARQ-ACK overhead for inter-band TDD CA in many cases. For instance,FIGS. 8A-8Billustrate an example, where the UE aggregates a total of three CCs with UL-DL configuration0in PCell, UL-DL configuration2in SCell1, and UL-DL configuration1in SCell2. Transmission mode4with two transport blocks (TB) enabled can be configured and spatial HARQ-ACK bundling may not be applied because the HARQ-ACK payload size is not greater than 20. The special subframe configuration of each CC can be configuration3with normal downlink CP. The eNB can transmit the downlink subframes at subframe1of PCell; subframes9,0,1, and3of Scell1; and subframe0of SCell2. Additionally, the UE can receive the uplink grant for the PUSCH transmission for subframe7. As a result, the total HARQ-ACK codebook size can be reduced from 18 to 14, as illustrated inFIG. 8B, which implies a reduction of HARQ-ACK overhead of up to 23%. As a consequence, the PUSCH performance and system throughput can be improved with little to no impact on HARQ-ACK performance (unlike puncturing).FIGS. 8A-Billustrate HARQ-ACK codebook piggybacking on the PUSCH scheduled with transmission mode4. The total HARQ-ACK bit numbers (or HARQ-bit numbers) can be represented by ‘O’ or ‘OACK’.FIG. 8Bcan be generated using Tables 5 and 6, and Equations 1-3.

From Equations 2 and 3, the HARQ-ACK codebook size reduction can depend on the WDAIULvalue. As previously stated, if an uplink DCI format (e.g., DCI format0/4) for PUSCH scheduling is restricted to be transmitted at the last DL subframe within each bundling window, the value of WDAIULmay be set by eNB according to the existing PDSCH scheduling information, which may not be complete in some inter-band TDD CA scenarios. By exploiting the timing relationship between the PUSCH scheduling and the last DL subframe within each bundling window, the HARQ-ACK codebook size can be minimized when the HARQ-ACK feedback piggybacked (e.g, transmitted) on the PUSCH. Unfortunately, some cases of inter-band TDD CA can exist when an uplink DCI format (e.g., DCI format0/4) for PUSCH scheduling is transmitted in the DL subframe in the middle of bundling window, as illustrated inFIG. 9.FIG. 9illustrates an example where the PCell is configured with TDD UL-DL configuration1and SCell is configured with TDD UL-DL configuration2. PCell subframe0can have a DAI=1 and subframe1can have a DAI=2, while SCell subframe9can have a DAI=1 and subframes0and1can have a DAI=2 with subframe3having an unknown DAI.FIG. 9depicts a potential issue for HARQ-ACK codebook determination for inter-band TDD CA. Since the PDSCH transmission in subframe #3in SCell may not be predicted by eNB for WDAIULsetting of the UL grant sent in subframe #1of PCell (i.e., WDAIULsent in subframe #1of PCell), a set of rules (e.g., modification of the calculation of the value BcDL) can be defined and provided to UE to avoid the HARQ-ACK codebook size ambiguity between UE and eNB.

For cases when PDSCH transmission in a HARQ bundling window occur after the transmission of a UL grant, as shown inFIG. 9, the HARQ-ACK bit generation method, as defined in Equation 3, may no longer be applicable and may not support this case. Because of the subsequent DL subframe (which may or may not be transmitted), which occurs after the DL subframe carrying the uplink DCI format (e.g., DCI format0/4), such as subframe #3of SCell inFIG. 9, the HARQ-ACK codebook size can be ambiguous. Therefore, the subsequent DL subframe may not be included in the WDAIULvalue when the uplink DCI format is transmitted. The technology (e.g., methods, computer circuitry, devices, processors, and UEs) described herein can be used to set the WDAIULvalue to minimize the HARQ-ACK codebook size and while still avoiding the ambiguity on HARQ-ACK codebook size between eNB and UE. The technology can be used for minimizing the HARQ-ACK book size for various cases.

In an example, a HARQ-ACK codebook size can be determined under a timing triggering condition when a DL subframe occurs after the DL DCI transmission with an uplink DCI format (e.g., DCI format0/4). Such DL subframe may not be predicted in advance by the eNB, therefore the subsequent PDSCH subframe may not be counted for the WDAIULvalue setting. Consequently, the WDAIULmay not be applicable for the entire HARQ bundling window and may cause a discrepancy on the HARQ-ACK codebook size between eNB and UE side, since UE may generate a legacy HARQ-ACK bits number solely depends on the WDAIULvalue in the uplink grant DCI (e.g., DCI format0/4) detected.FIG. 10illustrates a HARQ-ACK feedback model for an inter-band TDD CA system, where the subsequent PDSCH subframe (e.g., Part B) occurs after an uplink grant DCI.

Equation 3 may lead to ambiguity for HARQ-ACK generation and may not be applicable for the cases illustrated byFIGS. 9-10. The UE can make determinations and modifications to properly utilize the WDAIULvalue to minimize the HARQ-ACK codebook size without ambiguity. For example, the bundling window can be divided into two parts (e.g., parts A and B), as shown inFIG. 10. For part A, the HARQ-ACK codebook overhead can be properly reduced according to the WDAIULin the uplink DCI format (e.g., DCI format0/4). While for part B, if existing (e.g., a subsequent PDSCH subframe occurs after an uplink grant DCI), the subsequent PDSCH subframe can generate HARQ-ACK bits associated with each downlink subframe.

Additional details are provided of the examples related to Parts A and B. By reusing an existing HARQ-ACK bundling window definition, a bundling window can include a set of DL subframes associated with one UL subframe, which can carry the HARQ-ACK feedbacks as defined in Table 3.FIG. 10can illustrate HARQ-ACK codebook size determination to address the issue depicted inFIG. 9. InFIG. 10, the PDSCH bundling window of serving cell ‘j’, which is associated with UL subframe ‘n’, can be further divided into two parts: part A and B, according to the downlink subframe position relative to the DL subframe carrying the UL grant transmitted on serving cell ‘i’ where i≠j. The part A within a bundling window on serving cell ‘c’ can include McAnumber of DL subframes, and part B within a bundling window on serving cell ‘c’, if existed, can include McBnumber of DL subframes, and Mc=McA+McB. As shown inFIG. 10, the characteristic of the DL subframe in part B can be that these subframes are transmitted later than the downlink subframe conveyed the UL grant for PUSCH scheduling on UL subframe #n. In some cases, McBcan be equal to zero.

The HARQ-ACK codebook size can be expressed by Equation 4:
OACK=Σc=0NcellsDL−1(BcDL×CcDL)  [Equation 4],

where NcellsDLis the number of configured cells, CcDL=1 if transmission mode configured in the c-th serving cell supports one transport block or spatial HARQ-ACK bundling is applied, otherwise CcDL=2

In an example, several different BcDLdeterminations can be used corresponding to different TDD UL-DL configuration of serving cell ‘i’, which can be used for the case shown inFIG. 10and when PUCCH format3is configured.

In a first case, when PUCCH format3is configured for transmission of HARQ-ACK, HARQ-ACK is transmitted on the PUSCH in the subframe n adjusted by a detected PDCCH with an uplink DCI format (e.g., DCI format0/4), and the timing reference configuration of serving cell #i, on which UL grant is transmitted, is UL-DL configuration0; the UE can assume BcDLfor any one serving cell ‘c’ on PUSCH subframe ‘n’ as represented by Equation 5:
BcDL=Mc[Equation 5],

where Mcis the number of elements in the set K (as defined in Table 3) associated with subframe ‘n’ for HARQ-ACK feedback and the set K does not include a special subframe of UL-DL configurations0and5with normal downlink CP or the set K does not include a special subframe of UL-DL configurations0and4with extended downlink CP. Otherwise, for PUCCH format3is configured for transmission of HARQ-ACK, HARQ-ACK is transmitted on the PUSCH in the subframe n adjusted by a detected PDCCH with an uplink DCI format (e.g., DCI format0/4), and the timing reference configuration of serving cell #i, on which UL grant is transmitted, is UL-DL configuration0. The UE can assume BcDLfor any one serving cell ‘c’ on PUSCH subframe ‘n’ as represented by Equation 6:
BcDL=Mc−1  [Equation 6].

In an example, equation 5 and 6 can be used when an uplink DCI format does not transmit a value WDAIUL(e.g., UL-DL configuration0). Equation 5 can be used when no PDSCH or no data (e.g., only PDCCH transmission) are transmitted in special frames (e.g., UL-DL configurations0and5with normal downlink CP, or UL-DL configurations0or4with extended downlink CP). Equation 6 can be used when PDSCH or data are transmitted in special frames.

In a second case (e.g., the timing reference configuration of serving cell #i is not a UL-DL configuration0), first option, as illustrated byFIG. 10, where the HARQ-ACK transmission in an UL subframe ‘n’ and on PUSCH can be adjusted by an UL grant, the number of HARQ-ACK codebook size on PUSCH can be determined by Equation 7:

where U denotes the maximum value of Ucamong all the configured serving cells, Ucis the total number of received PDSCHs and PDCCH indicating downlink SPS release in subframe n−k within part A on the c-th serving cell, k ε K defined in Table 3; and WDAIULis determined by the Downlink Assignment Index (DAI) in an uplink DCI format (e.g., DCI format0/4) of serving cell in which UCI piggybacking on PUSCH, according to Table 6 in subframe n−k′, where k′ is defined in Table 5.

In the second case, the value of WDAIULmay only count the DL subframes transmitted no later than the DL subframe containing the UL grant for UL subframe n. This assumption can be valid considering the eNB may not precisely determine the transmission condition of subsequent subframe in Part B of the bundling window at the instant in time that the UL grant for subframe ‘n’ is transmitted.

FIG. 11provides an example of the HARQ-ACK codebook size determination for the second case. InFIG. 5, serving cell0can use configuration1, and serving cell1can use configuration2. Serving cell0subframe5can have a DAI=1, while serving cell1subframe6can have a DAI=1. The part B's PDSCH transmission (e.g, subframe8with DAI=2) may not be known by eNB scheduler, the UL grant with WDAIUL=1 can be transmitted on subframe #6on serving cell0according to the PDSCH transmission status within part A of the PDSCH bundling window. Using Equations 4 and 7, the number of total HARQ-ACK bits generated can be 6 bits assuming transmission mode 4 with two transport blocks (TBs) configured. The 6 HARQ-ACK bits generated by the technology herein reduces the HARQ-ACK codebook size relative to the 8 HARQ-ACK bits used to feedback HARQ-ACK with a legacy system or design.

In a second case (e.g., the timing reference configuration of serving cell #i is not a UL-DL configuration0), second option, the eNB can take the DL subframes of part B into consideration when determining the value of WDAIULin UL grant without a definitive determination of the subsequent PDSCH subframes in the HARQ bundling window by padding bits for the potential of additional PDSCH subframes. However, second case, second option can increase the HARQ-ACK overhead. For instance, as shown by the example inFIG. 11, the value of WDAIULcan be set as WDAIUL=2, instead of WDAIUL=1, in order to include part B. Consequently, the number of HARQ-ACK bits increases from 6 to 8 (as illustrated inFIG. 11) when two CCs are configured. In another example using the illustration ofFIG. 11, the number of additional HARQ-ACK bits can be considerably increased as the number of configured CCs is increased.

Another example provides a method500for Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook size generation for inter-band time division duplex (TDD) carrier aggregation (CA) at a user equipment (UE), as shown in the flow chart inFIG. 12. The method may be executed as instructions on a machine, computer circuitry, or a processor for the UE, where the instructions are included on at least one computer readable medium or one non-transitory machine readable storage medium. The method includes the operation of receiving configuration information including a physical downlink shared channel (PDSCH) bundling window for inter-band TDD CA including at least one downlink (DL) subframe using HARQ-ACK feedback, as in block510. The operation of dividing the PDSCH bundling window into a first part and a second part, wherein the first part includes DL subframes of all configured serving cells that occur no later than the DL subframe where a downlink control information (DCI) transmission for uplink scheduling on a serving cell is conveyed, and the second part includes physical downlink shared channel (PDSCH) subframes occurring after the DCI transmission of all the serving cells follows, as in block520. The next operation of the method can be generating the HARQ-ACK codebook size based on the first part and the second part, as in block530.

In an example, the HARQ-ACK codebook size on a physical uplink shared channel (PUSCH) can be represented by OACK=Σc=0NcellsDL−1(BcDL×CcDL), where NcellsDLis the number of configured cells, BcDLis the number of downlink subframes for which the UE needs to feedback HARQ-ACK bits for the c-th serving cell, c is a non-negative integer, and CcDL=1 if a transmission mode configured in the c-th serving cell supports one transport block (TB) or spatial HARQ-ACK bundling is applied, otherwise CcDL=2

In a configuration,

BcDL=min(McA,WDAIUL+4⁢⌈U-WDAIUL4⌉)+McB
when the DCI transmission includes a WDAIULvalue, where McAis a number of DL subframes in a first part, McBis a number of DL subframes in a second part, U denotes a maximum value of Ucamong configured serving cells, Ucis a total number of received PDSCHs and physical downlink control channels (PDCCH) indicating downlink semi-persistent scheduling (SPS) release in subframe n−k within the first part on the c-th serving cell, k ε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213, and WDAIULis determined by a downlink assignment index (DAI) in a DCI format where uplink control information (UCI) is transmitted on PUSCH according to a Table 7.3-Z of the TS 36.213 in subframe n−k′, where k′ is defined in the Table 7.3-Y of TS 36.213.

In another configuration,

BcDL=min(McA,WDAIUL+4⁢⌈U-WDAIUL4⌉)+McB
when the DCI transmission includes a WDAIULvalue, where McAis a number of DL subframes in a first part, McBis a number of DL subframes in a second part, U denotes a maximum value of Ucamong configured serving cells, Ucis a total number of received PDSCHs and physical downlink control channels (PDCCH) indicating downlink semi-persistent scheduling (SPS) release in subframe n−k within the first part on the c-th serving cell, k ε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213, and WDAIUL=2.

In still another configuration, BcDL=Mcwhen the DCI transmission does not include a WDAIULvalue, where Mc=McA+McBis a number of elements in the set kε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213 associated with subframe ‘n’ for HARQ-ACK feedback, and the set K does not include a PDSCH, McAis a number of DL subframes in a first part, and McBis a number of DL subframes in a second part. Otherwise, BcDL=Mc−1 when the DCI transmission does not include a WDAIULvalue, and where the set K does include does include a PDSCH.

In another example, the method can further include receiving an uplink grant in a DCI transmission including downlink assignment index (DAI) information in a value WDAIULfor the first part, wherein the DCI transmission is transmitted with a DCI format used for uplink grants. In another configuration, the method can further include transmitting HARQ-ACK feedback for PDSCH subframes of the HARQ bundling window with the calculated HARQ-ACK codebook size in uplink control information (UCI) on physical uplink shared channel (PUSCH).

In another configuration, the method includes the operation of receiving configuration information including a physical downlink shared channel (PDSCH) bundling window for inter-band TDD CA including at least one downlink (DL) subframe using HARQ-ACK feedback. The operation of triggering a division of the PDSCH bundling window into a first part and a second part when a PDSCH subframe in the PDSCH bundling window is transmitted after a downlink control information (DCI) transmission of a serving cell for an uplink grant, wherein the first part is associated with the DCI transmission of the serving cell for the uplink grant, and the second part represents HARQ-ACK feedback for PDSCH subframes occurring after the DCI transmission follows. The next operation of the method can be generating the HARQ-ACK codebook size based on the first part and the second part.

Another example provides functionality600of computer circuitry on a user equipment (UE) operable to determine a Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook size for inter-band time division duplex (TDD) carrier aggregation (CA), as shown in the flow chart inFIG. 13. The functionality may be implemented as a method or the functionality may be executed as instructions on a machine, where the instructions are included on at least one computer readable medium or one non-transitory machine readable storage medium. The computer circuitry can be configured to determine a HARQ bundling window for inter-band TDD CA including a number of downlink (DL) subframes using HARQ-ACK feedback, as in block610. The computer circuitry can be further configured to divide the HARQ bundling window into a first part and a second part, wherein the first part includes DL subframes of configured serving cells that occur no later than the DL subframe where a downlink control information (DCI) transmission for uplink scheduling on a serving cell is conveyed, and the second part includes physical downlink shared channel (PDSCH) subframes occurring after the DCI transmission of the serving cells, as in block620. The computer circuitry can also be configured to calculate the HARQ-ACK codebook size based on the first part and the second part, as in block630.

In an example, the HARQ-ACK codebook size on a physical uplink shared channel (PUSCH) can be represented by OACK=Σc=0NcellsDL−1(BcDL×CcDL), where NcellsDLis the number of configured cells, BcDLis the number of downlink subframes for which the UE needs to feedback HARQ-ACK bits for the c-th serving cell, c is a non-negative integer, and CcDL=1 if a transmission mode configured in the c-th serving cell supports one transport block (TB) or spatial HARQ-ACK bundling is applied, otherwise CcDL=2.

In a configuration,

BcDL=min(McA,WDAIUL+4⁢⌈U-WDAIUL4⌉)+McB
when a serving cell carrying the uplink grant is not an uplink-downlink (UL-DL) configuration0, where McAis a number of DL subframes in a first part, McBis a number of DL subframes in a second part, U denotes a maximum value of Ucamong configured serving cells, Ucis a total number of received PDSCHs and physical downlink control channels (PDCCH) indicating downlink semi-persistent scheduling (SPS) release in subframe n−k within the first part on the c-th serving cell, kε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213, and WDAIULis determined by a downlink assignment index (DAI) in a DCI format0or4of the serving cell in which uplink control information (UCI) is transmitted on PUSCH according to a Table 7.3-Z of the TS 36.213 in subframe n−k′, where k′ is defined in the Table 7.3-Y of TS 36.213.

In another configuration,

BcDL=min(McA,WDAIUL+4⁢⌈U-WDAIUL4⌉)+McB
when a serving cell carrying the uplink grant is not uplink-downlink (UL-DL) configuration0, where McAis a number of DL subframes in a first part, McBis a number of DL subframes in a second part, U denotes a maximum value of Ucamong configured serving cells, Ucis a total number of received PDSCHs and physical downlink control channels (PDCCH) indicating downlink semi-persistent scheduling (SPS) release in subframe n−k within the first part on the c-th serving cell, k ε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213, and WDAIUL=2.

In still another configuration, BcDL=Mcwhen a serving cell carrying the uplink grant is uplink-downlink (UL-DL) configuration0, a physical uplink control channel (PUCCH) format3is configured for a transmission of HARQ-ACK, and detection of a physical downlink control channel (PDCCH) with DCI format0or4corresponding to subframe ‘n’; where Mcis a number of elements in the set kε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213 associated with subframe ‘n’ for HARQ-ACK feedback, and the set K does not include a special subframe of UL-DL configurations0and5with normal downlink cyclic prefixing (CP) and the set K does not include a special subframe of UL-DL configurations0and4with extended downlink CP. Otherwise, BcDL=Mc−1 when a serving cell carrying the uplink grant is uplink-downlink (UL-DL) configuration0, a physical uplink control channel (PUCCH) format3is configured for a transmission of HARQ-ACK, and detection of a physical downlink control channel (PDCCH) with DCI format0or4corresponding to subframe ‘n’; where the set K does include a special subframe of UL-DL configurations0or5with normal downlink cyclic prefixing (CP) or the set K does include a special subframe of UL-DL configurations0or4with extended downlink CP.

In another example, the computer circuitry can be further configured to receive an uplink grant in a DCI transmission including downlink assignment index (DAI) information in a value WDAIULfor the first part, where the DCI transmission is transmitted with an Long Term Evolution (LTE) DCI format0or a DCI format4. In another configuration, the computer circuitry can be further configured to transmit HARQ-ACK codebook through the physical uplink shared channel (PUSCH) scheduled by the DCI for uplink scheduling.

In another example, the HARQ bundling window with HARQ bundling window size Mccan include a set of DL subframes associated with one uplink (UL) subframe which carries the HARQ-ACK feedbacks as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213. In another configuration, a TDD configuration of a primary cell (PCell) in the inter-band TDD CA can differ from a TDD configuration of a secondary cell (SCell) in the inter-band TDD CA.

In another example, the computer circuitry can be configured to determine a HARQ bundling window for inter-band TDD CA including a number of downlink (DL) subframes using HARQ-ACK feedback. The computer circuitry can be further configured to divide the HARQ bundling window into a first part and a second part, wherein the first part is associated with a downlink control information (DCI) transmission of a serving cell for uplink scheduling, and the second part represents HARQ-ACK feedback for physical downlink shared channel (PDSCH) subframes occurring after the DCI transmission. The computer circuitry can also be configured to calculate the HARQ-ACK codebook size based on the first part and the second part.

FIG. 14illustrates an example node (e.g., serving node710and cooperation node750), such as an eNB, and an example wireless device720(e.g., UE). The node can include a node device712and752. The node device or the node can be configured to communicate with the wireless device. The node device, device at the node, or the node can be configured to communicate with other nodes via a backhaul link748(optical or wired link), such as an X2 application protocol (X2AP). The node device can include a processor714and754and a transceiver716and756. The transceiver can be configured to transmit an uplink grant in a DCI transmission including downlink assignment index (DAI) information in a value WDAIULfor the first part, where the DCI transmission is transmitted with a DCI format used for uplink grants. The transceiver can also be configured to receive HARQ-ACK codebook through the physical uplink shared channel (PUSCH) scheduled by the DCI for uplink scheduling. The transceiver716and756can be further configured to communicate with the coordination node via an X2 application protocol (X2AP). The processor can be further configured to generate downlink channels and receive and process uplink channels. The serving node can generate both the PCell and the SCell. The node (e.g., serving node710and cooperation node750) can include a base station (BS), a Node B (NB), an evolved Node B (eNB), a baseband unit (BBU), a remote radio head (RRH), a remote radio equipment (RRE), a remote radio unit (RRU), or a central processing module (CPM).

The wireless device720(e.g., UE) can include a transceiver724and a processor722. The wireless device (i.e., device) can be configured to calculate a Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook size for time division duplex (TDD) carrier aggregation (CA), as described in500ofFIG. 12 or 600ofFIG. 13.

In another example, processor722can be configured to: Determine a HARQ bundling window for inter-band TDD CA including a number of downlink (DL) subframes using HARQ-ACK feedback; partition the HARQ bundling window into a first part and a second part, where the first part includes DL subframes of configured serving cells that occur no later than the DL subframe where a downlink control information (DCI) transmission for uplink scheduling on a serving cell is conveyed, and the second part includes physical downlink shared channel (PDSCH) subframes occurring after the DCI transmission of the serving cells; and determine the HARQ-ACK codebook size based on the first part and the second part and a DCI format.

In an example, the HARQ-ACK codebook size on a physical uplink shared channel (PUSCH) can be represented by OACK=Σc=0NcellsDL−1(BcDL×CcDL), where NcellsDLis the number of configured cells, BcDLis the number of downlink subframes for which the UE needs to feedback HARQ-ACK bits for the c-th serving cell, c is a non-negative integer, and CcDL=1 if a transmission mode configured in the c-th serving cell supports one transport block (TB) or spatial HARQ-ACK bundling is applied, otherwise CcDL=2.

In a configuration,

BcDL=min(McA,WDAIUL+4⁢⌈U-WDAIUL4⌉)+McB
when a serving cell carrying the uplink grant is not an uplink-downlink (UL-DL) configuration0, where McAis a number of DL subframes in a first part, McBis a number of DL subframes in a second part, U denotes a maximum value of Ucamong configured serving cells, Ucis a total number of received PDSCHs and physical downlink control channels (PDCCH) indicating downlink semi-persistent scheduling (SPS) release in subframe n−k within the first part on the c-th serving cell, kε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213, and WDAIULis determined by a downlink assignment index (DAD in a DCI format0or4of the serving cell in which uplink control information (UCI) is transmitted on PUSCH according to a Table 7.3-Z of the TS 36.213 in subframe n−k′, where k′ is defined in the Table 7.3-Y of TS 36.213.

In another configuration, BcDL=Mcwhen a serving cell carrying the uplink grant is uplink-downlink (UL-DL) configuration0, a physical uplink control channel (PUCCH) format3is configured for a transmission of HARQ-ACK, and detection of a physical downlink control channel (PDCCH) with DCI format0or4corresponding to subframe ‘n’; where Mcis a number of elements in the set kε K as defined in a Table 10.1.3.1-1 in a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard Release 11 Technical Specification (TS) 36.213 associated with subframe ‘n’ for HARQ-ACK feedback, and the set K does not include a special subframe of UL-DL configurations0and5with normal downlink cyclic prefixing (CP) and the set K does not include a special subframe of UL-DL configurations0and4with extended downlink CP. Otherwise, BcDL=Mc−1 when a serving cell carrying the uplink grant is uplink-downlink (UL-DL) configuration0, a physical uplink control channel (PUCCH) format3is configured for a transmission of HARQ-ACK, and detection of a physical downlink control channel (PDCCH) with DCI format0or4corresponding to subframe ‘n’; where the set K does include a special subframe of UL-DL configurations0or5with normal downlink cyclic prefixing (CP) or the set K does include a special subframe of UL-DL configurations0or4with extended downlink CP.

In another example, the transceiver724can be configured to receive an uplink grant in a DCI transmission including downlink assignment index (DAD information in a value WDAIULfor the first part, where the DCI transmission is transmitted with a DCI format used for uplink grants. In another configuration, the transceiver can be further configured to transmit HARQ-ACK codebook through the physical uplink shared channel (PUSCH) scheduled by the DCI for uplink scheduling to a node.

In another example, processor722can be configured to: Determine a HARQ bundling window for inter-band TDD CA including a number of downlink (DL) subframes using HARQ-ACK feedback; partition the HARQ bundling window into a first part and a second part, where the first part represents HARQ-ACK feedback for physical downlink shared channel (PDSCH) subframes occurring prior or during a downlink control information (DCI) transmission of a serving cell for uplink scheduling, and the second part represents HARQ-ACK feedback for PDSCH subframes occurring after the DCI transmission; and determine the HARQ-ACK codebook size based on the first part and the second part and a DCI format.

FIG. 15also provides an illustration of a microphone and one or more speakers that can be used for audio input and output from the wireless device. The display screen may be a liquid crystal display (LCD) screen, or other type of display screen such as an organic light emitting diode (OLED) display. The display screen can be configured as a touch screen. The touch screen may use capacitive, resistive, or another type of touch screen technology. An application processor and a graphics processor can be coupled to internal memory to provide processing and display capabilities. A non-volatile memory port can also be used to provide data input/output options to a user. The non-volatile memory port may also be used to expand the memory capabilities of the wireless device. A keyboard may be integrated with the wireless device or wirelessly connected to the wireless device to provide additional user input. A virtual keyboard may also be provided using the touch screen.