Patent Description:
Wireless communications networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stations (e.g., eNodeBs or eNBs) that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via the downlink and uplink.

<NPL>, relates to proposals for improving UL control signaling in enhanced carrier aggregation.

In some wireless communication networks, such as in Long Term Evolution (LTE), for example, a downlink assignment index (DAI) may be communicated by an eNB to an UE to prevent acknowledgment/negative-acknowledgment (ACK/NACK) errors that may occur as part of Hybrid Automatic Repeat Request (HARQ) operations in which the UE bundles ACK/NACK feedback to the eNB. The use of the DAI in systems in which multiple component carriers (CCs) are supported for carrier aggregation may present some challenges, particularly as the number of component carriers that are supported increases. Accordingly, it is desirable to have mechanisms that enable the use of a DAI in a wide range of carrier aggregation scenarios.

A method performed by a UE and a corresponding UE and computer-readable medium are defined by independent claims <NUM>, <NUM>, <NUM> respectively.

The features, nature, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout, where dashed lines may indicate optional components or actions, and wherein:.

However, it will be apparent to those skilled in the enhanced carrier aggregation (eCA) is provided. The computer readable medium includes code for receiving, at a user equipment (UE) and from a base station, a DAI indicating a total number of DL assignments or codewords; and code for interpreting, at the UE, the DAI received from the base station based at least on whether the DAI is received from the base station in a DL grant or a uplink (UL) grant.

According to another example, a method for downlink (DL) assignment index (DAI) management in an enhanced carrier aggregation (eCA) is provided. The example method includes determining, at a base station, whether to transmit a DAI in a DL grant or a uplink (UL) grant, wherein the DAI indicates a total number of DL assignments or codewords; and transmitting, from the base station, the DAI in the DL grant or the UL grant to one or more user equipments (UEs) based on the determination.

In another example, an apparatus for downlink (DL) assignment index (DAI) management in an enhanced carrier aggregation (eCA) is provided. The example apparatus may include means for determining, at a base station, whether to transmit a DAI in a DL grant or a uplink (UL) grant, wherein the DAI indicates a total number of DL assignments or codewords; and means for transmitting, from the base station, the DAI in the DL grant or the UL grant to one or more user equipments (UEs) based on the determination.

In a further example, an apparatus for downlink (DL) assignment index (DAI) management in an enhanced carrier aggregation (eCA) is provided that may include a memory configured to store data; and one or more processors communicatively coupled with the memory, wherein the one or more processors and the memory are configured to determine, at a base station, whether to transmit a DAI in a DL grant or a uplink (UL) grant, wherein the DAI indicates a total number of DL assignments or codewords; and transmit, from the base station, the DAI in the DL grant or the UL grant to one or more user equipments (UEs) based on the determination.

Additionally, in another example, a computer readable medium storing computer executable code for downlink (DL) assignment index (DAI) management in an enhanced carrier aggregation (eCA) is provided that may include code for determining, at a base station, whether to transmit a DAI in a DL grant or a uplink (UL) grant, wherein the DAI indicates a total number of DL assignments or codewords; and code for transmitting, from the base station, the DAI in the DL grant or the UL grant to one or more user equipments (UEs) based on the determination.

Various aspects and features of the disclosure are described in further detail below with reference to various examples thereof as shown in the accompanying drawings. While the present disclosure is described below with reference to various examples, it should be understood that the present disclosure is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and examples, as well as other fields of use, which are within the scope of the present disclosure as described herein, and with respect to which the present disclosure may be of significant utility.

In an aspect, the term "component" as used herein may be one of the parts that make up a system, may be hardware or software, and may be divided into other components.

The present aspects generally relate to downlink assignment index (DAI) management in carrier aggregation (CA), and particularly in carrier aggregation scenarios in which larger numbers of component carriers (CCs) or cells are being supported (e.g., enhanced carrier aggregation or eCA). Throughout this disclosure the terms component carriers and cells may be used interchangeably. In some implementations (e.g., in LTE Rel-<NUM>), a UE may be configured to support up to five (<NUM>) component carriers (CC) for carrier aggregation. For example, each component carrier may be configured with up to <NUM> and may be backward compatible (the UE may therefore be configured to support up to <NUM>). In carrier aggregation, all the component carriers - which may sometimes be referred to as cells - may operate in frequency division duplexing (FDD) or time division duplexing (TDD), or operate in a combination or mixture of FDD and TDD. In some instances, component carriers in TDD may have the same or different downlink (DL) and uplink (UL) configurations. In addition, special subframes may also be configured differently for different TDD component carriers.

In another aspect related to current implementations, one component carrier may be configured as the primary component carrier (PCC) for the UE. The PCC is the only component carrier that is configured to carry a Physical Uplink Control Channel (PUCCH) and a common search space for the UE. All other or remaining component carriers are termed secondary component carriers (SCCs). In these implementations, no adoption has been made of enabling PUCCH for a UE on two component carriers for carrier aggregation. In such a scheme, besides the PCC, one of the secondary component carriers or cell may carry PUCCH as well. This approach is at least partially motivated by dual-connectivity and PUCCH load balancing needs.

In some cases, component carriers may not have ideal backhaul capabilities, and consequently, very tight coordination between the various component carriers may not be possible because of the limited backhaul capacity and non-negligible backhaul latency (e.g., tens of milliseconds). The concept of dual-connectivity was therefore introduced recently (e.g., LTE Rel-<NUM>) to address the above scenario. In dual-connectivity, component carriers or cells may be partitioned into two groups, the primary cell group (PCG) and the secondary cell group (SCG). Each of these groups may have one or more cells in carrier aggregation. In addition, each of these groups may have a single cell carrying PUCCH. For example, a primary cell in PCG carries PUCCH for the PCG, and a secondary cell in SCG carries PUCCH for the SCG, also called the pScell. The common search space is also additionally monitored in the SCG by the UE. Uplink control information (UCI) may be separately conveyed to each group via the PUCCH in each group. Moreover, semi-static scheduling (SPS) and scheduling requests (SR) are not only supported in the PSG but are supported in the SCG as well.

In current efforts (e.g., LTE Rel-<NUM>), there is a push to increase the number of component carriers beyond five (<NUM>) component carriers to enable enhanced carrier aggregation (eCA). For example, PUCCH on a secondary cell (SCell) for UEs supporting uplink carrier aggregation may now be possible. In addition, the physical layer Specifications for PUCCH on SCell may be developed based on the necessary mechanisms that would enable LTE carrier aggregation of up to <NUM> component carriers for the downlink and uplink. Such mechanisms may include enhancements to downlink control signalling for up to <NUM> component carriers including both self-scheduling and cross-carrier scheduling, if any, as well as enhancements to uplink control signalling for up to <NUM> component carriers. The enhancements to uplink control signalling may involve enhancements to support UCI feedback on PUCCH for up to <NUM> downlink carriers by specifying the necessary enhancements to UCI feedback signalling formats, as well as enhancements to support UCI feedback on Physical Uplink Shared Channel (PUSCH) for up to <NUM> downlink carriers.

These efforts to increase the number of component carriers need also take into consideration the use of downlink assignment index (DAI) for HARQ feedback. In TDD, for example, multiple downlink (DL) subframes may be associated with a same uplink (UL) subframe for HARQ feedback. In order to more efficiently provide ACK/NACK feedback, a <NUM>-bit DAI may be included in DL grants and UL grants in TDD. When included in the DL grant, the <NUM>-bit DL DAI may indicate the accumulative number of DL assignments. When included in the UL grant, the <NUM>-bit UL DAI may indicate the total number of DL assignments. A UE may, based on the indicated total DAI, determine the number of ACK/NACK bits for feedback, and based on the indicated accumulative DAI, order the ACK/NACK bits of different DL subframes associated with the same UL subframe.

In TDD with carrier aggregation, the UL DAI may be used to indicate a maximum number of DL subframes scheduled in any of the multiple component carriers being supported. For example, when <NUM> component carriers are being used (i.e., CC1 and CC2), with DL CC1 and DL CC2 both having <NUM> DL subframes associated with the same UL subframe, and when only <NUM> of the DL subframes in CC1 are scheduled and only <NUM> of the DL subframes in CC2 are scheduled, the total DAI may indicate a value of <NUM>, representing the maximum number of scheduled DL subframes in each of the two component carriers.

For FDD, however, there may not be DAI involved, even under FDD with carrier aggregation. The use of DAI in FDD with carrier aggregation may be beneficial because, for example, instead of counting the number of DL assignments in time domain as in TDD, DAI in FDD may count in the component carrier-domain (e.g., frequency-domain) reflecting the number of component carriers or codewords that are scheduled.

For both FDD and TDD with carrier aggregation, when a TDD component carrier is used to carry PUCCH (thus the TDD component carrier is the primary cell, or the primary secondary cell), DAI may be added for DL grants and UL grants for the FDD component carrier (as a secondary cell). In other words, the FDD Scell Downlink Control Information (DCI) formats may be adapted to the TDD-like DCI formats when TDD is the primary cell or the primary secondary cell. Similarly, a TDD Scell Downlink Control Information (DCI) formats may be adapted to the FDD-like DCI formats when FDD is the primary cell or the primary secondary cell.

For enhanced carrier aggregation, because of the increased number of component carriers, DAI is to be used in both FDD and TDD component carriers, even if a UE has all FDD component carriers or when a FDD cell is the primary cell or the primary secondary cell. The manner in which DAI is to be defined for enhanced carrier aggregation has yet to be defined. Accordingly, aspects of the present disclosure provide details of various techniques or schemes for using or managing the use of DAI in enhanced carrier aggregation. Some of these aspects address issues such as the introduction of total DAI in DL grants even when accumulative DAI, which is counted in a frequency(CC)-first, time-second manner, is used. Other issues may include the number of bits for DAI in DL grants. In one example, for accumulative DAI, instead of <NUM>-bits it may be possible to use <NUM> bits, <NUM> bits, or <NUM> bits, or have the number of bits depend on the number of configured component carriers (e.g., <NUM>-<NUM> CCs, <NUM> bits, ><NUM> CCs, <NUM> bits). In another example, for total DAI, the number of bits may be <NUM> bits or <NUM> bits. Another issue being addressed by the various aspects described herein is the introduction of DAI in UL grants under FDD carrier aggregation even in cases when total DAI is already introduced in DL grants.

For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below.

<FIG> is a schematic diagram conceptually illustrating an example of a wireless communications system <NUM>, in accordance with an aspect of the present disclosure. The wireless communications system <NUM> includes base stations (or cells) <NUM>, user equipment (UEs) <NUM>, and a core network <NUM>. One or more base stations <NUM> may include a communications component <NUM> (see <FIG>) for DAI management in enhanced carrier aggregation (eCA) at network device, as described herein. One or more UEs <NUM> may include a communications component <NUM> (see <FIG>) for DAI management in eCA, as described herein. The base stations <NUM> may communicate with the UEs <NUM> under the control of a base station controller (not shown), which may be part of the core network <NUM> or the base stations <NUM> in various embodiments. The base stations <NUM> may communicate control information and/or user data with the core network <NUM> through first backhaul links <NUM>. In embodiments, the base stations <NUM> may communicate, either directly or indirectly, with each other over second backhaul links <NUM>, which may be wired or wireless communication links. The wireless communications system <NUM> may support operation on multiple carriers (waveform signals of different frequencies). Multi-carrier transmitters can transmit modulated signals simultaneously on the multiple carriers. For example, each communication link <NUM> may be a multi-carrier signal modulated according to the various radio technologies described above. Each modulated signal may be sent on a different carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, data, etc. The wireless communications system <NUM> may also support operation on multiple flows at the same time. In some aspects, the multiple flows may correspond to multiple wireless wide area networks (WWANs) or cellular flows. In other aspects, the multiple flows may correspond to a combination of WWANs or cellular flows and wireless local area networks (WLANs) or Wi-Fi flows.

The base stations <NUM> may wirelessly communicate with the UEs <NUM> via one or more base station antennas. Each of the base stations <NUM> sites may provide communication coverage for a respective geographic coverage area <NUM>. In some embodiments, base stations <NUM> may be referred to as a base transceiver station, a radio base station, an access point, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a NodeB, eNodeB, eNB, Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area <NUM> for a base station <NUM> may be divided into sectors making up only a portion of the coverage area (not shown). The wireless communications system <NUM> may include base stations <NUM> of different types (e.g., macro, micro, and/or pico base stations). There may be overlapping coverage areas for different technologies. In general, base stations <NUM>-a may be base stations corresponding to a WWAN (e.g., LTE or UMTS macro cell, pico cell, femto cell, etc. base stations). It is to be appreciated, however, that a single base station <NUM> can support communications over multiple RATs (e.g., LTE and Wi-Fi, LTE and UMTS, UMTS and Wi-Fi, etc.).

In implementations, the wireless communications system <NUM> is an LTE/LTE-A network communication system. In LTE/LTE-A network communication systems, the terms evolved Node B (eNodeB or eNB) may be generally used to describe the base stations <NUM>. The wireless communications system <NUM> may be a Heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographical regions. For example, each eNB <NUM> may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs <NUM> with service subscriptions with the network provider. A pico cell may cover a relatively smaller geographic area (e.g., buildings) and may allow unrestricted access by UEs <NUM> with service subscriptions with the network provider. A femto cell may also cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs <NUM> having an association with the femto cell (e.g., UEs <NUM> in a closed subscriber group (CSG), UEs <NUM> for users in the home, and the like). An eNB <NUM> for a macro cell may be referred to as a macro eNodeB. An eNB <NUM> for a pico cell may be referred to as a pico eNodeB. And, an eNB <NUM> for a femto cell may be referred to as a femto eNodeB or a home eNodeB. An eNB <NUM> may support one or multiple (e.g., two, three, four, and the like) cells.

The core network <NUM> may communicate with the eNBs <NUM> or other base stations <NUM> via first backhaul links <NUM> (e.g., S1 interface, etc.). The eNBs <NUM> may also communicate with one another, e.g., directly or indirectly via second backhaul links <NUM> (e.g., X2 interface, etc.) and/or via the first backhaul links <NUM> (e.g., through core network <NUM>). The wireless communications system <NUM> may support synchronous or asynchronous operation. For synchronous operation, the eNBs <NUM> may have similar frame timing, and transmissions from different eNBs <NUM> may be approximately aligned in time. For asynchronous operation, the eNBs <NUM> may have different frame timing, and transmissions from different eNBs <NUM> may not be aligned in time.

The UEs <NUM> may be dispersed throughout the wireless communications system <NUM>, and each UE <NUM> may be stationary or mobile. A UE <NUM> may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. A UE <NUM> may be able to communicate with macro eNBs, eNodeBs, pico eNodeBs, femto eNodeBs, relays, and the like.

The communication links <NUM> shown in the wireless communications system <NUM> may include uplink (UL) transmissions from a UE <NUM> to an eNB <NUM>, and/or downlink (DL) transmissions, from an eNB <NUM> to a UE <NUM>. The downlink transmissions may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions.

In certain aspects of the wireless communications system <NUM>, a UE <NUM> may be configured to support carrier aggregation (CA) with two or more eNBs <NUM>. The eNBs <NUM> that are used for carrier aggregation may be collocated or may be connected through fast connections. In either case, coordinating the aggregation of component carriers (CCs) for wireless communications between the UE <NUM> and the eNBs <NUM> may be carried out more easily because information can be readily shared between the various cells being used to perform the carrier aggregation. When the eNBs <NUM> that are used for carrier aggregation are non-collocated (e.g., far apart or do not have a highspeed connection between them), then coordinating the aggregation of component carriers may involve additional aspects.

<FIG> is a schematic diagram conceptually illustrating carrier aggregation, in accordance with aspects described herein. The aggregation may occur in a system <NUM> including an UE <NUM>-a (see <FIG>), which can communicate with an eNB <NUM>-a (see <FIG>) using one or more component carriers <NUM> through N (CC<NUM>-CCN). The eNB <NUM>-a may include a communications component <NUM>, as described herein, for performing aspects related to various schemes for DAI management in carrier aggregation, and particularly in enhanced carrier aggregation (eCA). UE <NUM>-a may include a communications component <NUM>, as described herein, for performing aspects related to various schemes for DAI management in carrier aggregation, and particularly in enhanced carrier aggregation. In this regard, the UE <NUM>-a supports at least a WWAN radio access technology (e.g., LTE). While only one UE <NUM>-a and an eNB <NUM>-a are illustrated in <FIG>, it will be appreciated that the system <NUM> can include any number of UEs <NUM>-a and/or eNBs <NUM>-a. In one specific example, UE <NUM>-a can communicate with one eNB <NUM>-a over one LTE component carrier <NUM> while communicating with another eNB <NUM>-a over another component carrier <NUM>.

The eNB <NUM>-a can transmit information to the UE <NUM>-a over forward (downlink) channels <NUM>-<NUM> through <NUM>-N on LTE component carriers CC<NUM> through CCN. In addition, the UE <NUM>-a can transmit information to the eNB <NUM>-a over reverse (uplink) channels <NUM>-<NUM> through <NUM>-N on LTE component carriers CC<NUM> through CCN. The number of component carriers supported by UE <NUM>-a and eNB <NUM>-a may be up to <NUM> component carriers, or more.

In describing the various entities of <FIG>, as well as other figures associated with some of the disclosed aspects, for the purposes of explanation, the nomenclature associated with a 3GPP LTE or LTE-A wireless network may be used. However, it is to be appreciated that the system <NUM> can operate in other networks such as, but not limited to, an OFDMA wireless network, a CDMA network, a 3GPP2 CDMA2000 network and the like.

In multi-carrier operations, the downlink control information (DCI) messages associated with different UEs <NUM>-a may be carried on multiple component carriers. For example, the DCI on a Physical Downlink Control Channel (PDCCH) may be included on the same component carrier that is configured to be used by an UE <NUM>-a for Physical Downlink Shared Channel (PDSCH) transmissions (i.e., same-carrier signaling). Alternatively, or additionally, the DCI may be carried on a component carrier different from the target component carrier used for PDSCH transmissions (i.e., cross-carrier signaling). In some implementations, a carrier indicator field (CIF), which may be semi-statically enabled, may be included in some or all DCI formats to facilitate the transmission of PDCCH control signaling from a carrier other than the target carrier for PDSCH transmissions (cross-carrier signaling).

<FIG> describes, in an aspect, a wireless communications system <NUM>, which may represent a portion of the wireless communications system <NUM> in <FIG>. The wireless communications system <NUM> includes at least one UE <NUM>-a in communication coverage of at least one network entity, in this example, an eNB <NUM>-a. UE <NUM>-a may communicate with a network via the eNB <NUM>-a. That is, UE <NUM>-a may transmit and/or receive wireless communications to and/or from eNB <NUM>-a via one or more communication links or channels <NUM>, which may include an uplink communication channel (or simply a uplink channel or a uplink) and a downlink communication channel (or simply a downlink channel or a downlink), such as but not limited to an uplink data channel and/or a downlink data channel. Such wireless communications may include, but are not limited to, data, audio and/or video information.

Referring to <FIG>, in accordance with the present disclosure, UE <NUM>-a may include a memory <NUM>, one or more processors <NUM> and a transceiver <NUM>. The memory <NUM>, one or more processors <NUM>, and the transceiver <NUM> may communicate internally via a bus <NUM>. In some examples, the memory <NUM> and the one or more processors <NUM> may be part of the same hardware component (e.g., may be part of a same board, module, or integrated circuit). Alternatively, the memory <NUM> and the one or more processors <NUM> may be separate components that may act in conjunction with one another. In some aspects, the bus <NUM> may be a communication system that transfers data between multiple components and subcomponents of the UE <NUM>-a. In some examples, the one or more processors <NUM> may include any one or combination of modem processor, baseband processor, digital signal processor and/or transmit processor. Additionally or alternatively, the one or more processors <NUM> may include or implement the functionalities of a communications component <NUM> for carrying out one or more methods, procedures, or schemes described herein. The communications component <NUM>, and each of its subcomponents, may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in memory <NUM> (e.g., a computer-readable storage medium). The communications component <NUM> may include a DAI manager <NUM>, described in more detail below with respect to <FIG>, and an HARQ manager <NUM>, which may be configured to manage various aspects of HARQ operations at UE <NUM>-a and which may coordinate and/or cooperate with the DAI manager <NUM> to perform the HARQ operations.

In some examples, the UE <NUM>-a may include the memory <NUM>, such as for storing data used herein and/or local versions of applications associated with communications component <NUM> and/or one or more of its subcomponents being executed by the one or more processors <NUM>. Memory <NUM> can include any type of computer-readable medium usable by a computer or processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory <NUM> may be a computer-readable storage medium (e.g., a non-transitory medium) that stores one or more computer-executable codes defining communications component <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when UE <NUM>-a is operating processor <NUM> to execute communications component <NUM> and/or one or more of its subcomponents. In some examples, the UE <NUM>-a may further include the transceiver <NUM> for transmitting and/or receiving one or more data and control signals to/from the network via eNB <NUM>-a. The transceiver <NUM> may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). The transceiver <NUM> may include a radio <NUM> (e.g., a LTE radio) comprising a modem <NUM>. The radio <NUM> may utilize one or more antennas <NUM> for transmitting signals to and receiving signals from eNB <NUM>-a.

In general, radio <NUM> may support orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink for LTE operations. For example, K may be equal to <NUM>, <NUM>, <NUM>, <NUM> or <NUM> for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM> or <NUM> megahertz (MHz), respectively. For example, a subband may cover <NUM>, and there may be <NUM>, <NUM>, <NUM>, <NUM> or <NUM> subbands for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM> or <NUM>, respectively.

As described above, LTE may also use carrier aggregation, including enhanced carrier aggregation. UEs (e.g., LTE-Advanced enabled UEs) may use spectrum of up to <NUM> bandwidth allocated in a carrier aggregation of up to a total of <NUM> (when <NUM> component carriers are being used) used for transmission and/or reception. For enhanced carrier aggregation (eCA), however, the number of component carriers that may be supported is up to <NUM>. For the LTE-Advanced enabled wireless communication systems, two types of carrier aggregation (CA) methods have been proposed, continuous CA and non-continuous CA. Continuous CA occurs when multiple available component carriers are adjacent to each other. On the other hand, non-continuous CA occurs when multiple non-adjacent available component carriers are separated along the frequency band. Both non-continuous and continuous CA may aggregate multiple component carriers to serve a single unit of LTE-Advanced UEs.

<FIG> is block diagram conceptually illustrating aspects of the DAI manager <NUM> in <FIG>. The DAI manager <NUM> supports various schemes or mechanisms described below to enable the use or management of DAI in enhanced carrier aggregation operations.

In one implementation, different DAI interpretations or bitwidths may be used in DL and UL grants. For example, when a total DAI is introduced in a DL grant, different interpretations may be used for the total DAI provided in the DL grant than for a total DAI provided in the UL grant. A total DAI in a DL grant may indicate a number of downlink assignments or codewords which may be over both a frequency and a time (e.g., two-dimensional counting). Additionally, the bitwidth of such total DAI may be at least <NUM> bits. In an additional or alternate implementation, a total DAI in UL grants need not be interpreted much differently from how it is currently interpreted. For example, in carrier aggregation with only frequency division duplex (FDD) carriers, a total DAI in UL grants is not introduced. That is, the total DAI is not indicated in the UL grant. In carrier aggregation with time division duplex (TDD) carriers, the DAI may indicate time-domain assignments and there may not be a change in the bitwidth for the DAI in the UL grant. That is, the number of bits that is currently used may be used. In other words, the DAI may indicate how many subframes have been scheduled, but not a number or count of how many assignments over different component carriers in a subframe. In carrier aggregation with FDD and TDD carriers, a <NUM>-bit DAI may be defined (similarly to the case of TDD with carrier aggregation) when a TDD carrier is used as a Physical Uplink Control Channel (PUCCH) cell or the DAI is not indicated when a TDD carrier is used as the PUCCH.

In another implementation, there may be different DAI interpretations depending on the number of configured component carriers (CCs) or configured ACK/NACK payload size. For example, the DAI bitwidth may be interpreted differently for different numbers of configured CCs. When the number of configured CCs is small (e.g., less than a threshold), the DAI may indicate the number of scheduled codewords. When the number of configured CCs is large (e.g., greater than or equal to the threshold), the DAI may indicate the number of scheduled CCs and/or subframes. In some cases, the threshold may be about <NUM> CCs. In another example, the same DAI bitwidth may be used regardless of the number of configured CCs. The different DAI interpretations may take into consideration whether a CC is a single-input-multiple-output (SIMO) (e.g., <NUM> bit) or multiple-input-multiple-output (MIMO) (e.g., <NUM> bits). For example, in an aspect, when the DAI bitwidth is <NUM>, and the number of configured CCs is less than <NUM>, the DAI may be interpreted to indicate the number of scheduled codewords. If the number of configured CCs is <NUM> or more, the DAI may be interpreted to indicate the number of scheduled CCs/subframes.

In yet another implementation, the DAI bitwidth may depend on at least two of the number of configured CCs, the transmission modes configured for the CCs, and the downlink association set size of each CC (e.g., number of DL subframes associated with an UL subframe for HARQ feedback). Generally, the DAI bitwidth may be dependent on the total HARQ payload size. For example, in some aspects, when the payload size is <NUM> bits or less, the DAI bitwidth may be <NUM> bits. When the payload size is <NUM>-<NUM> bits, the DAI bitwidth may be <NUM> bits; when the payload size is <NUM>-<NUM> bits, the DAI bitwidth may be <NUM> bits; and when the payload size is greater than <NUM> bits, the DAI bitwidth may be <NUM> bits. In an additional or optional aspect, the DAI bitwidth may depend on the PUCCH format. For example, if PUCCH format <NUM> (e.g., high capacity for HARQ) is configured for the UE, then a <NUM>-bit DAI may be assumed. If PUCCH format <NUM> (e.g., low capacity for HARQ) is configured for the UE, then a <NUM>-bit DAI may be assumed.

In yet another scheme or mechanism, the HARQ payload size granularity used for HARQ feedback may depend on whether total DAI is present. That is, when there is no total DAI in a DL grant and there is no UL grant (hence no total DAI from UL grants), a UE may determine the HARQ payload size based on comparing detected scheduled subframes (N_HARQ) to a first set of HARQ payload sizes (see e.g., set <NUM> corresponding to a first table of HARQ payload sizes in <FIG>). For example, when N_HARQ is <NUM>, the UE may determine, from set <NUM>, that the HARQ payload size is <NUM> because that is the minimum granularity or entry in the table of set <NUM> that is not less than <NUM>. Accordingly, the UE may select an HARQ payload size of <NUM> to provide HARQ feedback, even though <NUM> bits may go unused. However, when there is total DAI from UL grants or a total DAI from DL grants, a different set or table may be used (see e.g., set <NUM> corresponding to a second table of HARQ payload sizes in <FIG>). In this case, if the <NUM>-bit DAI from the UL grant indicates a value of <NUM>, it may mean that HARQ payload sizes of <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> may be used. Because the UE has detected N_HARQ to be <NUM>, the UE may determine that HARQ payload size to be <NUM> because that is the minimum granularity or entry in the table of set <NUM> that is not less than <NUM>. By using, in this example a table or set of HARQ payload sizes with more granularity, a saving of <NUM> bits may be possible.

The DAI manager <NUM> may be configured to support each of the schemes or mechanisms described above and further detailed below. It is to be understood that these schemes or mechanisms may be implemented independent from each other, two or more of these schemes or mechanisms may be implemented together, and/or aspects from two or more of these schemes or mechanisms may be combined. In this regard, the DAI manager <NUM> may include a DAI identifier <NUM> and a DAI interpreter <NUM>. The DAI manager <NUM> may also include, optionally, a HARQ payload size selector <NUM>. In some instances, aspects of the HARQ payload size selector <NUM> may be implemented, at least partially, in the HARQ manager <NUM> shown in <FIG>.

The DAI identifier <NUM> may be configured to identify a first DAI <NUM> having a DAI bitwidth <NUM>. The first DAI <NUM> may be a total DAI. The first DAI <NUM> may be received via a downlink grant from, for example, an eNB <NUM>-a. The DAI identifier <NUM> may be configured to optionally identify a second DAI <NUM> having a DAI bitwidth <NUM>. The second DAI <NUM> may be a total DAI. The second DAI <NUM> may be received via an uplink grant from, for example, an eNB <NUM>-a. When the first DAI <NUM> and the second DAI <NUM> are both total DAIs, the bitwidth value of the first DAI <NUM> may be different from the bitwidth value of the second DAI <NUM>.

The DAI interpreter <NUM> may be configured to implement various aspects of the interpretations and/or definitions described herein for DAI management in enhanced carrier aggregation. In one aspect, the DAI interpreter <NUM> may optionally include a comparator <NUM> configured to compare a number of configured CCs with a threshold <NUM> to determine whether the DAI indicates a number of scheduled codewords or instead indicates a number of scheduled component carriers and/or subframes.

The HARQ payload size selector <NUM> may be configured to detect scheduled frames (N_HARQ) using a scheduled subframes detector <NUM>, identify a set of HARQ payload sizes from multiple sets of HARQ payload sizes <NUM> (see e.g., sets <NUM> and <NUM> in <FIG>), and select a HARQ payload size <NUM> from the identified set based on the detected scheduled frames. It is to be understood that the sets or tables shown in <FIG> corresponding to HARQ payload sizes are provided by way of illustration and not of limitation.

<FIG> describes, in an aspect, a wireless communications system <NUM>, which may represent a portion of the wireless communications system <NUM> in <FIG>. The wireless communications system <NUM> includes at least one UE <NUM>-a in communication coverage of at least one network entity, in this example, an eNB <NUM>-a. UE <NUM>-a may communicate with a network via the eNB <NUM>-a. That is, UE <NUM>-a may transmit and/or receive wireless communication to and/or from eNB <NUM>-a via one or more communication links or channels <NUM>, which may include an uplink communication channel (or simply uplink channel) and a downlink communication channel (or simply downlink channel), such as but not limited to an uplink data channel and/or downlink data channel. Such wireless communications may include, but are not limited to, data, audio and/or video information.

Referring to <FIG>, in accordance with the present disclosure, eNB <NUM>-a may include a memory <NUM>, one or more processors <NUM> and a transceiver <NUM>. The memory <NUM>, one or more processors <NUM>, and the transceiver <NUM> may communicate internally via a bus <NUM>. In some examples, the memory <NUM> and the one or more processors <NUM> may be part of the same hardware component (e.g., may be part of a same board, module, or integrated circuit). Alternatively, the memory <NUM> and the one or more processors <NUM> may be separate components that may act in conjunction with one another. In some aspects, the bus <NUM> may be a communication system that transfers data between multiple components and subcomponents of the eNB <NUM>-a. In some examples, the one or more processors <NUM> may include any one or combination of modem processor, baseband processor, digital signal processor and/or transmit processor. Additionally or alternatively, the one or more processors <NUM> may include or implement the functionalities of a communications component <NUM> for carrying out one or more methods, procedures, or schemes described herein. The communications component <NUM>, and each of its subcomponents, may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). The communications component <NUM> may include a DAI manager <NUM>, described in more detail below with respect to <FIG>, and a HARQ manager <NUM>, which may be configured to manage various aspects of HARQ operations in eNB <NUM>-a and which may coordinate and/or cooperate with the DAI manager <NUM> to perform the HARQ operations.

In some examples, the eNB <NUM>-a may include the memory <NUM>, such as for storing data used herein and/or local versions of applications associated with communications component <NUM> and/or one or more of its subcomponents being executed by the one or more processors <NUM>. Memory <NUM> can include any type of computer-readable medium usable by a computer or processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory <NUM> may be a computer-readable storage medium (e.g., a non-transitory medium) that stores one or more computer-executable codes defining communications component <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when eNB <NUM>-a is operating processor <NUM> to execute communications component <NUM> and/or one or more of its subcomponents. In some examples, the eNB <NUM>-a may further include the transceiver <NUM> for transmitting and/or receiving one or more data and control signals to/from the network via UE <NUM>-a. The transceiver <NUM> may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). The transceiver <NUM> may include a radio <NUM> (e.g., LTE radio) comprising a modem <NUM>. The radio <NUM> may utilize one or more antennas <NUM> for transmitting signals to and receiving signals from UE <NUM>-a. The radio <NUM> and the modem <NUM> may provide substantially the same functionality as the radio <NUM> and the modem <NUM> described above with respect to <FIG>.

<FIG> is block diagram conceptually illustrating aspects of the DAI manager <NUM> in <FIG>. The DAI manager <NUM> may support the various schemes or mechanisms described herein to enable the use or management of DAI in enhanced carrier aggregation operations. The DAI manager <NUM> may include a DAI determiner <NUM> configured to determine one or more DAI bitwidths and/or bitwidth values for communicating DAI to a UE. In one example, the DAI determiner <NUM> may determine a first DAI <NUM> having a DAI bitwidth <NUM>. The first DAI <NUM> may be a total DAI, and may be communicated to a UE (e.g., UE <NUM>-a) via a DL grant. The DAI determiner <NUM> may optionally determine a second DAI <NUM> having a DAI bitwidth <NUM>. The second DAI <NUM> may be a total DAI, and may be communicated to the UE via an UL grant. When the first DAI <NUM> and the second DAI <NUM> are both total DAIs, the bitwidth value of the first DAI <NUM> may be different from the bitwidth value of the second DAI <NUM>.

In an additional aspect, the DAI determiner <NUM> may be further configured to determine the bitwidth of a DAI (e.g., DAI bitwidth <NUM> of first DAI <NUM> or DAI bitwidth <NUM> of second DAI <NUM>) based on a number of configured component carriers (CCs) <NUM> and at least one of additional parameters <NUM>. The additional parameters <NUM> may include, as described above, at least one of a transmission mode <NUM>, a DL associate set size <NUM>, a total HARQ payload size <NUM>, or a PUCCH format <NUM>.

<FIG> and <FIG> are flow diagrams conceptually illustrating examples of methods for DAI management in enhanced carrier aggregation, in accordance with various aspects of the present disclosure. Although the operations described below are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Also, although the communications components <NUM> and <NUM> are illustrated as having a number of subcomponents, it should be understood that one or more of the illustrated subcomponents may be separate from, but in communication with, the communications components <NUM> and <NUM>, and/or each other. Moreover, it should be understood that any of actions or components described below with respect to the communications components <NUM> and <NUM> and/or their subcomponents may be performed by a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component specially configured for performing the described actions or components (see e.g., <FIG>).

Referring to <FIG>, in an aspect, at block <NUM>, method <NUM> includes receiving, at a user equipment (UE) and from a base station, a DAI indicating a total number of DL assignments or codewords. For example, in an aspect, UE <NUM>-a and/or DAI manager <NUM> may include a DAI identifier <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory to receive, at UE <NUM>-<NUM> and from base station <NUM>-<NUM>, a DAI indicating a total number of DL assignments or codewords (from base station <NUM>-a). That is, UE <NUM>-<NUM> may receive DAI <NUM> from the base station <NUM>-<NUM> in the DL grant and/or or DAI <NUM> in the UL grant.

At block <NUM>, method <NUM> includes interpreting, at the UE, the DAI received from the base station based at least on whether the DAI is received from the base station in a DL grant or a uplink (UL) grant. For example, in an aspect, UE <NUM>-a and/or DAI manager <NUM> may include a DAI interpreter <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory to interpret, at the UE <NUM>-a, the DAI (e.g., DAI <NUM> or DAI <NUM>) received from the base station <NUM>-a based at least on whether the DAI is received from the base station in the DL grant or the UL grant.

In one implementation, for example, UE <NUM>-a may receive DAI <NUM> from base station <NUM>-a in a DL grant. The DAI identifier <NUM> may identify that the DAI indicates a total number of DL assignments or codewords from the base station <NUM>-a. The total number of DL assignments or codewords may be over both a frequency and a time (e.g., two-dimensional counting). The bitwidth <NUM> associated with DAI <NUM> may be at least two. Additionally, the presence of DAI <NUM> in the DL grant may be based (e.g., dependent) on at least the number of carriers in the enhanced carrier aggregation. For instance, the DAI <NUM> may be present in the DL grant when the number of carriers is above a threshold, for example, five. For example, the DAI <NUM> may be present in the DL grant when the number of carriers in the eCA is five or more. Further, DAI interpreter <NUM> may interpret the DAIs separately if more than one PUCCH groups are identified at the UE.

In another implementation, for example, UE <NUM>-a may receive DAI <NUM> from base station <NUM>-a in an UL grant. The DAI identifier <NUM> may identify that the DAI <NUM> indicates a total number of DAI assignments or codewords from the base station <NUM>-a. The total number of DL assignments or codewords may be over a time. In an aspect, DAI <NUM> is not included in the UL grant when the eCA includes only FDD CCs. In an additional aspect, when the eCA includes only TDD CCs, the DAI <NUM> may indicate the total number of DL assignments or codewords over a time for at least one carrier of the eCA. In a further additional or optional aspect, when the eCA includes both FDD and TDD CCs, DAI <NUM> may be received with a DAI bitwidth <NUM> of two when a TDD CC is configured as a PUCCH cell. Alternately, DAI <NUM> is not received when a FDD CC is configured as the PUCCH cell.

Referring to <FIG>, in an aspect, at block <NUM>, method <NUM> includes determining, at a base station, whether to transmit a DAI in a DL grant or a uplink (UL) grant, wherein the DAI indicates a total number of DL assignments or codewords. For example, in an aspect, base station <NUM>-a and/or DAI manager <NUM> may include a DAI determiner <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory to determine, at base station <NUM>-a, whether to transmit a DAI in a DL grant or a uplink (UL) grant, wherein the DAI indicates a total number of DL assignments or codewords. For instance, when the base station <NUM>-a determines to transmit the DAI in the DL grant, base station <NUM>-a may transmit DAI <NUM> with a bitwidth <NUM> and/or when the base station <NUM>-a determines to transmit the DAI in the UL grant, base station <NUM>-a may transmit DAI <NUM> with a bitwidth <NUM>.

At block <NUM>, method <NUM> includes transmitting, from the base station, the DAI in the DL grant or the UL grant to one or more user equipments (UEs) based on the determination. For example, in an aspect, base station <NUM>-a and/or DAI manager <NUM> may include a DAI transmitter <NUM>, such as a specially programmed processor module, or a processor executing specially programmed code stored in a memory to transmit, from base station <NUM>-a, DAI <NUM> in the DL grant and/or DAI <NUM> in UL grant to one or more UEs <NUM>-a based on the determination. In an additional aspect, DAI manager <NUM> may consider one or more of a transmission mode of each of the configured CCs, a DL associate set size <NUM> for each of the configured CCs, a total HARQ payload size <NUM>, and/or a PUCCH format <NUM> for determining and/or transmitting the DAI to the UE.

In some aspects, an apparatus or any component of an apparatus may be configured to (or operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.

It should be understood that any reference to an element herein using a designation such as "first," "second," and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements. In addition, terminology of the form "at least one of A, B, or C" or "one or more of A, B, or C" or "at least one of the group consisting of A, B, and C" used in the description or the claims means "A or B or C or any combination of these elements. " For example, this terminology may include A, or B, or C, or A and B, or A and C, or A and B and C, or 2A, or 2B, or 2C, and so on.

The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two.

Accordingly, an aspect of the disclosure can include a computer readable medium embodying a method for dynamic bandwidth management for transmissions in unlicensed spectrum. Accordingly, the disclosure is not limited to the illustrated examples.

Claim 1:
A method (<NUM>), performed by a user equipment, of downlink, DL, assignment index, DAI, management in an enhanced carrier aggregation, eCA, the method comprising:
receiving (<NUM>) from a base station,a DAI;
interpreting (<NUM>) the DAI received from the base station based at least on whether the DAI is received in a DL grant or an uplink, UL, grant;
determining Hybrid Automatic Repeat Request, HARQ, payload size granularity for HARQ feedback, the determining comprising:
identifying a HARQ payload size based on comparing detected scheduled subframes to either a first table of HARQ payload sizes or a second table of HARQ payload sizes, wherein the second table of HARQ payload sizes has a greater granularity than the first table, and wherein the second table is utilized when the DAI indicates a total number of DL assignments or codewords; and
transmitting HARQ feedback based on the identified HARQ payload size to the base station based on the interpretation of the DAI.