Patent Description:
As telecommunications technology has evolved, more advanced network access equipment has been introduced that can provide services that were not possible previously. This network access equipment might include systems and devices that are improvements of the equivalent equipment in a traditional wireless telecommunications system. Such advanced or next generation equipment may be included in evolving wireless communications standards, such as long-term evolution (LTE). For example, an LTE system might include an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) node B (eNB), a wireless access point, or a similar component rather than a traditional base station. Any such component will be referred to herein as an eNB, but it should be understood that such a component is not necessarily an eNB. Such a component may also be referred to herein as an access node.

LTE may be said to correspond to Third Generation Partnership Project (3GPP) Release <NUM> (Rel-<NUM> or R8) and Release <NUM> (Rel-<NUM> or R9), while LTE Advanced (LTE-A) may be said to correspond to Release <NUM> (Rel-<NUM> or R10) and possibly also to Release <NUM> (Rel-<NUM> or R11) and other releases beyond Release <NUM>. As used herein, the terms "legacy", "legacy UE", and the like might refer to signals, UEs, and/or other entities that comply with LTE Release <NUM> and/or earlier releases but do not fully comply with releases later than Release <NUM>. The terms "advanced", "advanced UE", and the like might refer to signals, UEs, and/or other entities that comply with LTE Release <NUM> and/or later releases. While the discussion herein deals with LTE systems, the concepts are equally applicable to other wireless systems as well. Ericsson ER AL "Cross-carrier scheduling in aggregation of carriers with different UL/DL configurations" discloses LTE Interband TDD carrier aggregation with cross-carrier scheduling and different configurations in use on the different bands. Thus the PHICH is always sent on the primary cell, even when the PUSCH is sent on the secondary cell. If the secondary cell configuration is expecting a PHICH at a certain subframe, but no PHICH is available in that subframe in the primary cell configuration, PHICH is punctured onto the PDCCH in that subframe.

In an LTE system, downlink and uplink transmissions are organized into one of two duplex modes, frequency division duplex (FDD) mode and time division duplex (TDD) mode. The FDD mode uses paired spectrum where the frequency domain is used to separate the uplink (UL) and downlink (DL) transmissions. In TDD systems, on the other hand, unpaired spectrum is used where both UL and DL are transmitted over the same carrier frequency. The UL and DL are separated in the time domain. <FIG> illustrates both duplex modes.

In a 3GPP LTE TDD system, a subframe of a radio frame can be a downlink, an uplink or a special subframe. The special subframe comprises downlink and uplink time regions separated by a guard period for downlink to uplink switching. 3GPP Technical Specification (TS) <NUM> defines seven different UL/DL configuration schemes in LTE TDD operations. The schemes are listed in <FIG>, where D represents downlink subframes, U represents uplink subframes, and S represents a special frame. A special frame includes three parts: the downlink pilot time slot (DwPTS), the uplink pilot time slot (UpPTS), and the guard period (GP). Downlink transmissions on the Physical Downlink Shared Channel (PDSCH) may be made in DL subframes or in the DwPTS portion of the special subframe.

As <FIG> shows, there are two switching point periodicities specified in the LTE standard, <NUM> milliseconds (ms) and <NUM>. <NUM> switching point periodicity is introduced to support the co-existence between LTE and low chip rate UTRA TDD systems, and <NUM> switching point periodicity is for the coexistence between LTE and high chip rate UTRA TDD systems. The supported configurations cover a wide range of UL/DL allocations from a DL-heavy <NUM>:<NUM> ratio to a UL-heavy <NUM>:<NUM> ratio. The DL allocations in these ratios include both DL subframes and special subframes, which can also carry downlink transmissions in the DwPTS. Compared to FDD, TDD systems have more flexibility in terms of the proportion of resources assignable to uplink and downlink communications within a given assignment of spectrum. Specifically, it is possible to distribute the radio resources unevenly between the uplink and the downlink. Such a distribution may allow the radio resources to be utilized efficiently through the selection of an appropriate UL/DL configuration based on the interference situation and different traffic characteristics in the DL and the UL.

The UL and DL transmissions may not be continuous in an LTE TDD system. That is, UL or DL transmissions may not occur in every subframe. Therefore, the data channel transmissions with their scheduling grant and Hybrid Automatic Repeat Request (HARQ) timing relationships are separately defined in the 3GPP specifications. Currently, the HARQ acknowledgement/negative acknowledgement (ACK/NACK) timing relationship for downlink data channel transmission is defined by Table <NUM>. <NUM>-<NUM> in 3GPP TS <NUM>. This timing relationship is shown in Table <NUM> below. Table <NUM> associates a UL ACK/NACK transmission at sub-frame n, with a DL PDSCH transmission at sub-frames n - ki, i = <NUM> to M - <NUM>.

The uplink HARQ ACK/NACK timing linkage with the PUSCH transmission is listed in Table <NUM>-<NUM> of 3GPP TS <NUM>, which is provided as Table <NUM> below. Table <NUM> indicates that the Physical HARQ Indicator Channel (PHICH) carrying an ACK/NACK received in DL sub-frame i is linked with the UL data transmission in UL sub-frame i - k, where k is given in Table <NUM>. For UL/DL configuration <NUM>, in sub-frames <NUM> and <NUM>, if IPHICH= <NUM>, then k = <NUM>. Otherwise k = <NUM>. This is because there may be two ACK/NACKs for a UE transmitted on the PHICH in subframes <NUM> and <NUM>.

The relationship of a UL grant and/or an ACK/NACK with a UL transmission/retransmission is listed in Table <NUM> of 3GPP TS <NUM>, which is provided as Table <NUM> below. The UE, upon detection of a Physical Downlink Control Channel (PDCCH) with Downlink Control Information (DCI) format <NUM> and/or a PHICH transmission in sub-frame n intended for the UE, sends the corresponding PUSCH transmission in sub-frame n + k, where k is given in Table <NUM>.

For TDD UL/DL configuration <NUM>, if the Least Significant Bit (LSB) of the UL index in DCI format <NUM> is set to <NUM> in sub-frame n or a PHICH is received in sub-frame n = <NUM> or <NUM> in the resource corresponding to IPHICH = <NUM> or a PHICH is received in sub-frame n = <NUM> or <NUM>, the UE sends the corresponding Physical Uplink Shared Channel (PUSCH) transmission in sub-frame n + <NUM>. If, for TDD UL/DL configuration <NUM>, both the Most Significant Bit (MSB) and the LSB of the UL index in DCI format 0are set to <NUM> in sub-frame n, the UE sends the corresponding PUSCH transmission in both sub-frames n + k and n + <NUM>, where k is given in Table <NUM>.

It can be seen that both grant and HARQ timing linkage in TDD are more complicated than the fixed time linkages used in FDD. Accordingly, TDD usually requires more attention in design.

The PHICH specified in 3GPP TS <NUM> is used to transmit a HARQ-ACK, which indicates whether the eNB has correctly received UL shared channel (UL-SCH) data on the PUSCH. Multiple PHICHs can be transmitted in the same set of resource elements as a PHICH group. In the same PHICH group, multiple PHICHs may be multiplexed with different complex orthogonal Walsh sequences. In the case of a normal cyclic prefix, eight PHICHs can be multiplexed within one PHICH group as the length of the sequences is four and the PHICHs are also multiplexed in the complex domain. For an extended cyclic prefix, four PHICHs can be multiplexed within a PHICH group with length-<NUM> Walsh sequences. <FIG> illustrates the PHICH modulation flow at the eNB.

For PHICH resource configuration, two parameters are signaled in the Master Information Block (MIB): the PHICH duration and the number of PHICH groups. The PHICH duration defines the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols over which the PHICH is distributed. To avoid a dependency on the Physical Control Format Indicator Channel (PCFICH), the PHICH duration is independently signaled and can be different from the control region for the PDCCH. The number of PHICH groups is used to define the amount of PHICH resources. The correspondence between PHICH resources and UL-SCH transmission is implicit. That is, there is a predefined representation rule between the PHICH resource index and the PUSCH Physical Resource Block (PRB) index transmitting the UL-SCH. Because there is a PUSCH transmission without a PDCCH in the case of resource non-adaptive retransmission, a PHICH resource is linked to the actual PUSCH PRB index instead of the PDCCH Control Channel Element (CCE) index.

The PHICH resource is identified by the index pair <MAT> where <MAT> is the PHICH group number and <MAT> is the orthogonal sequence index within the group. As PHICH resource is implicitly linked to the PUSCH PRB index that is used to transmit the corresponding PUSCH, a UE may derive the assigned index pair with the scheduled PUSCH PRB index. If a PHICH resource is smaller than the number of PUSCH PRBs or if multiple users are scheduled in the same PUSCH PRBs, a collision can happen. That is, the same PHICH resource may be assigned to multiple UEs. To avoid a collision, a different cyclic shift value that is indicated in the uplink DCI format may be used to derive the assigned PHICH resource. The following equations are used to determine the PHICH group number and the orthogonal sequence index within the group: <MAT> <MAT>.

In the above equations, nDMRS is mapped from the cyclic shift for a Demodulation Reference Signal (DMRS) field according to the most recent PDCCH with uplink DCI format, as described in 3GPP TS <NUM> for the transport block or blocks associated with the corresponding PUSCH transmission. nDMRS is set to zero if there is no PDCCH with uplink DCI format for the same transport block, and if the initial PUSCH for the same transport block is semi-persistently scheduled or if the initial PUSCH for the same transport block is scheduled by a random access response grant. <MAT> is the spreading factor size used for PHICH modulation as described in section <NUM>. <NUM> of 3GPP TS <NUM>. <MAT> is the lowest PRB index in the first slot of the corresponding PUSCH transmission. <MAT> is the number of PHICH groups configured by higher layers as described in section <NUM> of 3GPP TS <NUM>.

For FDD, the index <MAT> ranges from <NUM> to <MAT>. For TDD, the number of PHICH groups may vary between downlink subframes and is given by <MAT> where mi is given by Table <NUM>. The index <MAT> in a downlink subframe with non-zero PHICH resources ranges from <NUM> to <MAT>.

The PCFICH is currently used to indicate the number of OFDM symbols used for transmission of PDCCHs in each subframe. This number is called the Control Format Indicator (CFI). There are three different CFI code words used in the current version of LTE and a fourth one is reserved for future use. Each codeword is <NUM> bits in length. <FIG> illustrates the PCFICH modulation flow at an eNB.

In the current LTE specification, the PCFICH and the PHICH use different resource elements. The PCFICH takes four Resource Element Groups (REGs) and the PHICH consumes three REGs. <FIG> shows the modulation chain at an eNB and the demodulation chain at a UE.

To meet LTE-A requirements, the Rel-<NUM> LTE specification defines carrier aggregation (CA) for TDD systems. However, the Rel-<NUM> specification supports CA only with the same UL/DL configuration on the aggregated carriers because intra-band CA is prioritized, and having different UL/DL configurations is impossible to support in intra-band CA, especially when one single RF chain is used.

To achieve bandwidth flexibility and coexistence with legacy TDD systems, inter-band carrier aggregation with different TDD UL/DL configurations on the carriers from different bands has been proposed in LTE Rel-<NUM>. Many design details, such as supporting both half duplex and full duplex modes, supporting both separate scheduling (s-scheduling) and cross-carrier scheduling (c-scheduling), transmitting the PHICH on the cell carrying the UL grant, and transmitting the PUCCH only on the primary cell, have been agreed upon. Some agreements have also been reached on HARQ timing linkage.

It should be noted that a component carrier (CC) is also known as a serving cell or a cell. Furthermore, when multiple CCs are scheduled, for each UE, one of the CCs is designated as the primary carrier which is used for PUCCH transmission, semi-persistent scheduling, etc., while the remaining CCs are configured as secondary CCs. This primary carrier is also known as a PCell (Primary cell), while the secondary CC is known as an SCell (Secondary cell).

As discussed above, the timing linkage in TDD systems is not as simple as in FDD systems. The degree of complexity increases when CA with different TDD configurations is considered. This is because, with different TDD configurations, there are some time instances with conflicting subframes among aggregated CCs. For example, a UL subframe on CC1 may occur at the same time that CC2 has a DL subframe. Also, the timing linkage may be different for each different TDD configuration and, furthermore, certain control signals may have to be on a specific carrier. For example, the PHICH may have to be transmitted on the cell carrying the UL grant. These conditions may lead to a need to transmit a PUSCH ACK/NACK at a DL subframe that does not have a PHICH resource configured according to Table <NUM> above.

One of the 3GPP design agreements indicates that the PHICH can be transmitted only on the cell carrying the UL grant in the case of inter-band CA with different UL/DL configurations. Therefore, a PUSCH ACK/NACK may need to be transmitted at a DL subframe that does not have a PHICH resource configured.

In an example case, two TDD carriers may be aggregated, the PCell may be set as UL/DL configuration <NUM>, and the SCell may have UL/DL configuration <NUM>, in full duplex mode. Based on the 3GPP design principles, the PCell follows its own UL HARQ timing relationship, which is configuration <NUM>, and the SCell UL HARQ follows the timing of configuration <NUM>. In this case, the PCell with UL/DL configuration <NUM> is the scheduling cell and carries the UL grant for the SCell, so the PUSCH ACK/NACK should be on the PCell as well. <FIG> illustrates the UL HARQ timing of the above scenario. The solid arrows represent the SCell UL grant for transmission/retransmission, and the dashed arrows represent the UL HARQ-ACK timing of the SCell.

It can be seen that the ACK/NACK for PUSCH transmission at subframe #<NUM> or #<NUM> of the SCell should be at subframe #<NUM> of the PCell. However, with UL/DL configuration <NUM>, referring to Table <NUM> above, there is no PHICH resource provisioned in the control region of PCell subframe #<NUM>. The same issue occurs for the PUSCH transmission at subframes #<NUM> and #<NUM> of the SCell. Additionally, there is no PHICH resource provisioned at subframe #<NUM> of the PCell.

Embodiments of the present disclosure can resolve these PHICH resource issues by provisioning PHICH resources for a CA UE. New PHICH resources are provisioned in the control region of a DL subframe where the SCell PUSCH transmissions for CA UEs need to be acknowledged. The newly provisioned PHICH resource is recognized only by CA UEs.

In an embodiment, a new PHICH resource specifically for a CA UE is provisioned, if needed, in the control region of the previous zero-PHICH DL subframe, for example, subframe #<NUM> or #<NUM> in <FIG>. The newly provisioned PHICH resource is recognized only by CA UEs. Legacy UEs will consider that this resource is being used for PDCCH transmission. The new resource will be discarded by legacy UEs because the PDCCH blind decoding is not able to pick the resource up. Therefore, there is no backward compatibility impact to legacy UEs.

This PHICH resource provisioning is performed on an as-needed basis. For example, in <FIG>, when there is no cross-carrier scheduled PUSCH on SCell subframe #<NUM> and #<NUM>, there is no requirement to provision any PHICH resource at subframe #<NUM> of the PCell. The resource at that subframe may still be used for PDCCH purposes.

The following steps may be used in this method. (<NUM>) Given the UL/DL configurations of the PCell and the SCell, config(P) and config(S), identify the reference configuration, config(R), which the SCell PUSCH HARQ timing follows. (<NUM>) Identify the PHICH resource factor mi for config(P) and config(R) based on Table <NUM>, Pmi, Rmi, i=<NUM>, <NUM>, <NUM>,. (<NUM>) On a radio frame basis, determine if there is an index i, such that Pmi= <NUM> and Rmi > <NUM>. If 'Yes', go to step (<NUM>). Otherwise, go to step (<NUM>) as there is no need to provision a PHICH resource. (<NUM>) Further determine if there is a need to provision a PHICH resource at subframe #i of the PCell by checking if there is a PUSCH transmission on the SCell that requires an ACK/NACK on subframe #i of the PCell. If 'Yes', provision the PHICH resource. Otherwise, go to Step (<NUM>) as there is no need to provision a PHICH resource. (<NUM>) End.

<FIG> presents a flowchart depicting these steps. At block <NUM>, the PHICH resource factor mi for config(P) and config(R) is identified based on Table <NUM>, Pmi, Rmi, i=<NUM>, <NUM>, <NUM>,. At block <NUM>, it is determined if there is i such that Pmi = <NUM> and Rmi > <NUM>. If the determination in block <NUM> is negative, then at block <NUM>, PHICH resources are provisioned as in Rel <NUM>/<NUM>/<NUM>. If the determination in block <NUM> is positive, then at block <NUM>, it is determined whether an SCell PUSCH ACK/NACK is needed on subframe #i of the PCell. If the determination in block <NUM> is negative, then at block <NUM>, it is determined that there is no need to provision a PHICH resource at PCell subframe #i. If the determination in block <NUM> is positive, then at block <NUM>, a PHICH resource is provisioned for a carrier aggregation UE based on Rmi. It can be seen that the scheme in this flowchart will provision the PHICH resource at zero-PHICH subframes of the PCell if needed.

At least two schemes can be used to provision a PHICH resource for a CA UE in the control region. A first scheme involves puncturing onto the existing control region. In this scheme, the control region resource allocation still follows the previous release rule at the zero-PHICH DL subframe. Advanced CA UE PHICH resource allocation may follow the same method as in previous releases for a non-zero-PHICH subframe. However, the CA UE PHICH resource is punctured onto the existing control region. The puncturing may damage the PDCCH common search space, but since a higher aggregation level (<NUM> or <NUM>) is used in the PDCCH common search space, the punctured REG is only <NUM>/<NUM> or <NUM>/<NUM>, and the UEs (both advanced and legacy) should still be able to correctly decode the PDCCH in the common search space. The impact on error detection probability is expected to be low in this approach. Moreover, the puncturing loss on the PDCCH can be compensated by boosting the power on the PDCCH. An advanced UE may have an advantage since it may know the position of the punctured resource elements. In a UE-specific search space, an eNB can purposely put the PDCCH at the candidates that are not punctured.

Alternatively, the CA UE PHICH resource may be punctured onto one CCE at a UE-specific search space. This CCE may be at a fixed location which is known to all advanced CA UEs or may be set semi-statically by higher layer signaling. One group of PHICHs takes three REGs, and one CCE contains nine REGs. So, three groups of PHICH resources can be available in this scheme. An eNB can purposely avoid using the punctured CCE for the PDCCH.

A second scheme that can be used to provision a PHICH resource for a CA UE in the control region involves using a special PDCCH. In this scheme, the control region resource allocation still follows the previous release rule at the zero-PHICH DL subframe. For an advanced CA UE, the PHICH is inside a special PDCCH. A special Radio Network Temporary Identifier (RNTI), which is known to all CA UEs, may be assigned for this purpose. The previous PHICH process may be maintained inside the special PDCCH. Alternatively, instead of using a special RNTI to locate the special PDCCH, a fixed location known to all CA UEs or a semi-statically signaled location may be used for this special PDCCH. In this way, the <NUM>-bit Cyclic Redundancy Check (CRC) will not be transmitted, and more PHICH groups can be accommodated inside the special PDCCH. A third alternative is to use the same PDCCH generation process to treat ACK/NACK bits as DCI payload, using a special RNTI, channel coding, rate matching, and QPSK modulation. The channel coding rate may be semi-statically adjustable to obtain the best performance and capacity trade-off. This second scheme for provisioning a PHICH resource in the control region may extend to the PDSCH resource region as well, such as an enhanced PHICH (ePHICH).

As the provisioned PHICH resource for a CA UE may otherwise be used for the PDCCH, the PDCCH capacity may be slightly impacted. However, compared to an adaptive retransmission solution, this second solution is more resource efficient since the same resource allocation method as in Release <NUM>/<NUM>/<NUM> can be used. Multiple PHICHs are transmitted over the same set of resource elements.

The above may be implemented by a network element. A simplified network element is shown with regard to <FIG>. In <FIG>, network element <NUM> includes a processor <NUM> and a communications subsystem <NUM>, where the processor <NUM> and communications subsystem <NUM> cooperate to perform the methods described above.

Further, the above may be implemented by a UE. An example of a UE is described below with regard to <FIG>. UE <NUM> may comprise a two-way wireless communication device having voice and data communication capabilities. In some embodiments, voice communication capabilities are optional. The UE <NUM> generally has the capability to communicate with other computer systems on the Internet. Depending on the exact functionality provided, the UE <NUM> may be referred to as a data messaging device, a two-way pager, a wireless e-mail device, a cellular telephone with data messaging capabilities, a wireless Internet appliance, a wireless device, a smart phone, a mobile device, or a data communication device, as examples.

Where the UE <NUM> is enabled for two-way communication, it may incorporate a communication subsystem <NUM>, including a receiver <NUM> and a transmitter <NUM>, as well as associated components such as one or more antenna elements <NUM> and <NUM>, local oscillators (LOs) <NUM>, and a processing module such as a digital signal processor (DSP) <NUM>. The particular design of the communicafion subsystem <NUM> may be dependent upon the communication network in which the UE <NUM> is intended to operate.

Network access requirements may also vary depending upon the type of network <NUM>. In some networks, network access is associated with a subscriber or user of the UE <NUM>. The UE <NUM> may require a removable user identity module (RUIM) or a subscriber identity module (SIM) card in order to operate on a network. The SIM/RUIM interface <NUM> is typically similar to a card slot into which a SIM/RUIM card may be inserted. The SIM/RUIM card may have memory and may hold many key configurations <NUM> and other information <NUM>, such as identification and subscriber-related information.

When required network registration or activation procedures have been completed, the UE <NUM> may send and receive communication signals over the network <NUM>. As illustrated, the network <NUM> may consist of multiple base stations communicating with the UE <NUM>.

Signals received by antenna <NUM> through communication network <NUM> are input to receiver <NUM>, which may perform such common receiver functions as signal amplification, frequency down conversion, filtering, channel selection, and the like. Analog to digital (A/D) conversion of a received signal allows more complex communication functions, such as demodulation and decoding to be performed in the DSP <NUM>. In a similar manner, signals to be transmitted are processed, including modulation and encoding for example, by DSP <NUM> and are input to transmitter <NUM> for digital to analog (D/A) conversion, frequency up conversion, filtering, amplification, and transmission over the communication network <NUM> via antenna <NUM>. DSP <NUM> not only processes communication signals but also provides for receiver and transmitter control. For example, the gains applied to communication signals in receiver <NUM> and transmitter <NUM> may be adaptively controlled through automatic gain control algorithms implemented in DSP <NUM>.

The UE <NUM> generally includes a processor <NUM> which controls the overall operation of the device. Communication functions, including data and voice communications, are performed through communication subsystem <NUM>. Processor <NUM> also interacts with further device subsystems such as the display <NUM>, flash memory <NUM>, random access memory (RAM) <NUM>, auxiliary input/output (I/O) subsystems <NUM>, serial port <NUM>, one or more keyboards or keypads <NUM>, speaker <NUM>, microphone <NUM>, other communication subsystem <NUM> such as a short-range communications subsystem, and any other device subsystems generally designated as <NUM>. Serial port <NUM> may include a USB port or other port currently known or developed in the future.

Some of the illustrated subsystems perform communication-related functions, whereas other subsystems may provide "resident" or on-device functions. Notably, some subsystems, such as keyboard <NUM> and display <NUM>, for example, may be used for both communication-related functions, such as entering a text message for transmission over a communication network, and device-resident functions, such as a calculator or task list.

Operating system software used by the processor <NUM> may be stored in a persistent store such as flash memory <NUM>, which may instead be a read-only memory (ROM) or similar storage element (not shown). The operating system, specific device applications, or parts thereof, may be temporarily loaded into a volatile memory such as RAM <NUM>. Received communication signals may also be stored in RAM <NUM>.

As shown, flash memory <NUM> may be segregated into different areas for both computer programs <NUM> and program data storage <NUM>, <NUM>, <NUM> and <NUM>. These different storage types indicate that each program may allocate a portion of flash memory <NUM> for their own data storage requirements. Processor <NUM>, in addition to its operating system functions, may enable execution of software applications on the UE <NUM>. A predetermined set of applications that control basic operations, including at least data and voice communication applications for example, may typically be installed on the UE <NUM> during manufacturing. Other applications may be installed subsequently or dynamically.

Applications and software may be stored on any computer-readable storage medium. The computer-readable storage medium may be tangible or in a transitory/non-transitory medium such as optical (e.g., CD, DVD, etc.), magnetic (e.g., tape), or other memory currently known or developed in the future.

One software application may be a personal information manager (PIM) application having the ability to organize and manage data items relating to the user of the UE <NUM> such as, but not limited to, e-mail, calendar events, voice mails, appointments, and task items. One or more memory stores may be available on the UE <NUM> to facilitate storage of PIM data items. Such a PIM application may have the ability to send and receive data items via the wireless network <NUM>. Further applications may also be loaded onto the UE <NUM> through the network <NUM>, an auxiliary I/O subsystem <NUM>, serial port <NUM>, short-range communications subsystem <NUM>, or any other suitable subsystem <NUM>, and installed by a user in the RAM <NUM> or a non-volatile store (not shown) for execution by the processor <NUM>. Such flexibility in application installation may increase the functionality of the UE <NUM> and may provide enhanced on-device functions, communication-related functions, or both. For example, secure communication applications may enable electronic commerce functions and other such financial transactions to be performed using the UE <NUM>.

In a data communication mode, a received signal such as a text message or web page download may be processed by the communication subsystem <NUM> and input to the processor <NUM>, which may further process the received signal for output to the display <NUM>, or alternatively to an auxiliary I/O device <NUM>.

A user of the UE <NUM> may also compose data items, such as email messages for example, using the keyboard <NUM>, which may be a complete alphanumeric keyboard or telephone-type keypad, among others, in conjunction with the display <NUM> and possibly an auxiliary I/O device <NUM>. Such composed items may then be transmitted over a communication network through the communication subsystem <NUM>.

For voice communications, overall operation of the UE <NUM> is similar, except that received signals may typically be output to a speaker <NUM> and signals for transmission may be generated by a microphone <NUM>. Alternative voice or audio I/O subsystems, such as a voice message recording subsystem, may also be implemented on the UE <NUM>. Although voice or audio signal output may be accomplished primarily through the speaker <NUM>, display <NUM> may also be used to provide an indication of the identity of a calling party, the duration of a voice call, or other voice call-related information, for example.

Serial port <NUM> may be implemented in a personal digital assistant (PDA)-type device for which synchronization with a user's desktop computer (not shown) may be desirable, but such a port is an optional device component. Such a port <NUM> may enable a user to set preferences through an external device or software application and may extend the capabilities of the UE <NUM> by providing for information or software downloads to the UE <NUM> other than through a wireless communication network. The alternate download path may, for example, be used to load an encryption key onto the UE <NUM> through a direct and thus reliable and trusted connection to thereby enable secure device communication. Serial port <NUM> may further be used to connect the device to a computer to act as a modem.

Other communications subsystems <NUM>, such as a short-range communications subsystem, are further optional components which may provide for communication between the UE <NUM> and different systems or devices, which need not necessarily be similar devices. For example, the subsystem <NUM> may include an infrared device and associated circuits and components or a Bluetooth™ communication module to provide for communication with similarly enabled systems and devices. Subsystem <NUM> may further include non-cellular communications such as WiFi, WiMAX, near field communication (NFC), and/or radio frequency identification (RFID). The other communications element <NUM> may also be used to communicate with auxiliary devices such as tablet displays, keyboards or projectors.

The UE and other components described above might include a processing component that is capable of executing instructions related to the actions described above. <FIG> illustrates an example of a system <NUM> that includes a processing component <NUM> suitable for implementing one or more embodiments disclosed herein. In addition to the processor <NUM> (which may be referred to as a central processor unit or CPU), the system <NUM> might include network connectivity devices <NUM>, random access memory (RAM) <NUM>, read only memory (ROM) <NUM>, secondary storage <NUM>, and input/output (I/O) devices <NUM>. These components might communicate with one another via a bus <NUM>. In some cases, some of these components may not be present or may be combined in various combinations with one another or with other components not shown. These components might be located in a single physical entity or in more than one physical entity. Any actions described herein as being taken by the processor <NUM> might be taken by the processor <NUM> alone or by the processor <NUM> in conjunction with one or more components shown or not shown in the drawing, such as a digital signal processor (DSP) <NUM>. Although the DSP <NUM> is shown as a separate component, the DSP <NUM> might be incorporated into the processor <NUM>.

The processor <NUM> executes instructions, codes, computer programs, or scripts that it might access from the network connectivity devices <NUM>, RAM <NUM>, ROM <NUM>, or secondary storage <NUM> (which might include various disk-based systems such as hard disk, floppy disk, or optical disk). While only one CPU <NUM> is shown, multiple processors may be present. Thus, while instructions may be discussed as being executed by a processor, the instructions may be executed simultaneously, serially, or otherwise by one or multiple processors. The processor <NUM> may be implemented as one or more CPU chips.

The network connectivity devices <NUM> may take the form of modems, modem banks, Ethernet devices, universal serial bus (USB) interface devices, serial interfaces, token ring devices, fiber distributed data interface (FDDI) devices, wireless local area network (WLAN) devices, radio transceiver devices such as code division multiple access (CDMA) devices, global system for mobile communications (GSM) radio transceiver devices, universal mobile telecommunications system (UMTS) radio transceiver devices, long term evolution (LTE) radio transceiver devices, worldwide interoperability for microwave access (WiMAX) devices, and/or other well-known devices for connecting to networks. These network connectivity devices <NUM> may enable the processor <NUM> to communicate with the Internet or one or more telecommunications networks or other networks from which the processor <NUM> might receive information or to which the processor <NUM> might output information. The network connectivity devices <NUM> might also include one or more transceiver components <NUM> capable of transmitting and/or receiving data wirelessly.

The RAM <NUM> might be used to store volatile data and perhaps to store instructions that are executed by the processor <NUM>. The ROM <NUM> is a non-volatile memory device that typically has a smaller memory capacity than the memory capacity of the secondary storage <NUM>. ROM <NUM> might be used to store instructions and perhaps data that are read during execution of the instructions. Access to both RAM <NUM> and ROM <NUM> is typically faster than to secondary storage <NUM>. The secondary storage <NUM> is typically comprised of one or more disk drives or tape drives and might be used for non-volatile storage of data or as an over-flow data storage device if RAM <NUM> is not large enough to hold all working data. Secondary storage <NUM> may be used to store programs that are loaded into RAM <NUM> when such programs are selected for execution.

The I/O devices <NUM> may include liquid crystal displays (LCDs), touch screen displays, keyboards, keypads, switches, dials, mice, track balls, voice recognizers, card readers, paper tape readers, printers, video monitors, or other well-known input/output devices. Also, the transceiver <NUM> might be considered to be a component of the I/O devices <NUM> instead of or in addition to being a component of the network connectivity devices <NUM>.

In an embodiment, a method for communication in a wireless telecommunication system is provided. The method comprises provisioning, by a network element, for a carrier aggregation-capable UE, in a control region of a downlink subframe, at least one resource for a PHICH.

In another embodiment, a network element in a wireless telecommunication system is provided. The network element comprises a processor configured such that the network element provisions, for a carrier aggregation-capable UE, in a control region of a downlink subframe, at least one resource for a PHICH.

The following are incorporated herein by reference for all purposes: 3GPP TS <NUM>, 3GPP TS <NUM>, and 3GPP TS <NUM>.

Claim 1:
A method for communication in a wireless telecommunication system, the method comprising:
determining (<NUM>), by a network element (<NUM>), that a physical uplink shared channel, PUSCH, transmission scheduled on a subframe of a secondary cell, SCell, requires an acknowledgement/negative acknowledgement, ACK/NACK, on a downlink subframe of a primary cell, PCell, associated with the network element; and
provisioning (<NUM>), by the network element, for a carrier aggregation-capable user equipment, UE (<NUM>), in a control region of the downlink subframe of the PCell, at least one resource for a physical hybrid automatic repeat request, HARQ, indicator channel, PHICH, wherein the downlink subframe of the PCell is not configured for a PHICH resource in an uplink/downlink configuration for operations using only the PCell,
wherein provisioning the at least one PHICH resource includes:
determining, by the network element, a reference uplink/downlink configuration which the SCell PUSCH HARQ ACK/NACK timing follows, the reference uplink/downlink configuration is determined based on uplink/downlink configurations of the PCell and SCell;
based on the reference uplink/downlink configuration, identifying, by the network element, the downlink subframe to provision the at least one PHICH resource and a PHICH resource factor for the downlink subframe; and
provisioning the at least one PHICH resource based on the identified PHICH resource factor in the control region of the downlink subframe of the PCell.