HK1165170A - Method and apparatus for selecting and reselecting an uplink primary carrier - Google Patents

Description

Method and apparatus for selecting and reselecting uplink primary carrier

Cross Reference to Related Applications

This application claims the benefit of U.S. provisional application 61/159,665 filed on 3/12/2009 and U.S. provisional application 61/218,271 filed on 6/18/2009, the contents of which are incorporated by reference as if fully set forth herein.

Technical Field

The present application relates to wireless communications.

Background

In multicarrier communications, Downlink (DL) information reporting is typically performed on the Uplink (UL) for only one DL carrier at a time. Therefore, existing multicarrier communication systems lack techniques for reporting control information for more than one concurrent DL carrier on the UL.

For example, the third generation partnership project (3GPP) Long Term Evolution (LTE) system is a multi-carrier communication system. For the LTE DL direction, a transmission scheme based on an Orthogonal Frequency Division Multiple Access (OFDMA) air interface is used. According to OFDMA, an evolved node b (enb) may allocate wireless transmit/receive units (WTRUs) to receive their data anywhere in the entire LTE transmission bandwidth. For the LTE UL direction, Single Carrier (SC) transmission based on discrete fourier transform spread OFDMA (DFT-S-OFDMA) or, equivalently, single carrier frequency division multiple access (SC-FDMA) is used. In FDMA schemes, WTRUs perform transmission in the LTE UL direction only in limited but contiguous assigned subcarriers.

Fig. 1 illustrates a process of mapping a transport block 10 to an LTE carrier 20 for UL or DL transmission. Layer 1(L1)30 receives information from the hybrid automatic repeat request (HARQ) entity 40 and the scheduler 50 and uses this information to assign transport blocks 10 to LTE carriers 20. As shown in fig. 1, a UL or DL LTE carrier 20 (or just carrier 20) is made up of multiple subcarriers 60. The eNB may receive a composite UL signal from one or more WTRUs simultaneously throughout the entire transmission bandwidth, where each WTRU transmits over a subset of the available transmission bandwidth or subcarriers.

Currently, the 3GPP standardization body is developing LTE-advanced (LTE-a) in order to further improve the achievable throughput and coverage of LTE-based radio access systems and to meet the International Mobile Telecommunications (IMT) advanced requirements of 1Gbps and 500Mbps in the DL and UL directions, respectively. Proposed for LTE-a in the improvements proposed for LTE is carrier aggregation and support of flexible bandwidth permutations. LTE-a proposes to allow DL and UL transmission bandwidths to exceed the 20MHz limit in LTE, e.g. allowing 40MHz or 100MHz bandwidths. In this case, the carrier may occupy the entire frequency block. The proposed use of LTE-a allows more flexible use of the available paired spectrum. For example, LTE may be limited to operating in a symmetric and paired FDD mode, in which both the DL and UL may have a transmission bandwidth of 10MHz (or 20MHz), for example.

In contrast, LTE-a proposes to work also in an asymmetric configuration, in which mode, for example, a DL bandwidth of 10MHz can be paired with an UL bandwidth of 5 MHz. In addition, LTE-a also proposes a composite aggregate transmission bandwidth that can be backward compatible with LTE. As an example, the DL may include a first 20MHz carrier plus a second 10MHz carrier, where the carriers are paired with a 20MHz UL carrier. Carriers transmitted in parallel in the same UL or DL direction are called Component Carriers (CCs). In the frequency domain, the composite aggregate transmission bandwidth of CCs is not necessarily contiguous. Continuing with the present example, it is possible that the first 10MHz CC is spaced 22.5MHz apart from the second 5MHz DL CC in the DL band. Alternatively, the operation may use a contiguous aggregate transmission bandwidth. For example, a first DL CC of 15MHz may be aggregated with another DL CC of 15MHz and may be paired with a UL carrier of 20 MHz.

In the DL direction of LTE systems, a WTRU transmits its data (and in some cases its control information) on a Physical Downlink Shared Channel (PDSCH). The transmission of PDSCH is scheduled and controlled by the eNB using DL scheduling assignments, which are carried on the Physical Downlink Control Channel (PDCCH). As part of the DL scheduling assignment, the WTRU receives control information regarding the Modulation and Coding Scheme (MCS) and DL resource allocation (i.e., the index of the allocated resource block). Then, if a scheduling assignment is received, the WTRU decodes the PDSCH resources allocated for the WTRU on the correspondingly allocated DL resources.

In an LTE-a radio access system, at least one PDSCH may be transmitted to a WTRU on more than one assigned CC. Different methods for allocating PDSCH resources on more than one CC by using a carrier aggregation mechanism have been proposed.

In the LTE-a system, the PDCCH (or a Downlink Control Information (DCI) message included therein and transmitting assignment information) may be transmitted separately for CCs including an accompanying PDSCH transmission. For example, if there are two CCs, then there are two separate DCI messages on each CC, corresponding to PDSCH transmissions on each CC. Alternatively, two independent DCI messages for a WTRU may be sent on one CC even though they may involve accompanying data or PDSCH transmission on different CCs. Independent DCI messages for the PDCCH of at least one WTRU may be transmitted in one or more carriers, but not necessarily all of these messages are transmitted on each CC. For example, a first DCI transmission on a PDCCH involving a PDSCH allocation on a first CC is also included on the first CC, but for a WTRU PDCCH transmission involving a PDSCH allocation on a second CC, a second DCI for the transmission is included on the second CC.

For DCI carrying assignment information for PDSCH on more than one CC, the DCI may be jointly encoded and transmitted by one single joint DCI control message or PDCCH message. For example, the WTRU receives a single DCI or PDCCH or control message that carries an assignment of PDSCH or data resources on two CCs. Alternatively, a joint PDCCH for a WTRU or a group of WTRUs may be transmitted in one or more carriers.

In LTE-a systems using carrier aggregation, there is an asymmetric scheme for configuring WTRUs with a larger number of DL carriers than UL carriers. Since this is the case for LTE, one-to-one mapping cannot be performed between the designated DL carrier and UL carrier.

Of particular interest is UL carrier assignment for the Physical Uplink Control Channel (PUCCH), which is used to convey HARQ feedback as well as Channel Quality Indicator (CQI)/Precoding Matrix Indicator (PMI)/Rank Indicator (RI). Also, UL carrier assignment of Scheduling Request (SR) on Physical Random Access Channel (PRACH), and buffer status and power headroom on UL Synchronization Channel (SCH) are also of interest. If more than one DL carrier is mapped to a single UL carrier (i.e., a single PUCCH), there is a possibility of causing collision in the L1HARQ feedback.

Disclosure of Invention

Disclosed are methods and apparatus to support the need for HARQ feedback, CQI, SR, power headroom, and at least one buffer status report in the case of asymmetric and symmetric configurations by using UL primary carrier for LTE-A.

Drawings

A more detailed understanding can be obtained from the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 shows the principle of LTE transmission;

figure 2 shows an example wireless communication system including a plurality of wireless transmit/receive units (WTRUs) and an eNB;

figure 3 shows an example functional block diagram of the WTRU and eNB of figure 2;

fig. 4 is a flow diagram of a one-direction intra-cell handover procedure that lacks (less) RACH;

fig. 5 is a flow chart of a one-way intra-cell handover procedure;

fig. 6 is a flow chart of a one-way intra-cell handover procedure;

figure 7 shows an example block diagram of a WTRU;

fig. 8 is a flow chart of a unidirectional UL handover procedure; and

fig. 9 is a flow diagram of a process for sending HARQ feedback.

Detailed Description

When referred to hereafter, the terminology "wireless transmit/receive unit (WTRU)" includes but is not limited to a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a Personal Digital Assistant (PDA), a computer, or any other device capable of operating in a wireless environment.

When referred to hereafter, the terminology "base station" includes but is not limited to a node-B, a site controller, an Access Point (AP), or any other interfacing device capable of operating in a wireless environment.

The network may assign at least one DL carrier and/or at least one UL carrier as a primary DL carrier and a primary UL carrier, respectively. In multi-carrier operation, a WTRU may be configured to operate on two or more carriers (i.e., frequencies or cells). Each of the carriers may have different characteristics and logical associations between the network and the WTRUs, and the operating frequencies may be grouped and referred to as primary or anchor carriers and supplemental or secondary carriers.

Fig. 2 shows an LTE wireless communication system/access network 70 that includes an evolved universal terrestrial radio access network (E-UTRAN) 80. The E-UTRAN 80 includes several eNBs 150. The WTRU100 communicates with the eNB 150. The enbs 150 interface with each other using an X2 interface. Each eNB150 interfaces with one Mobility Management Entity (MME)/serving gateway (S-GW)180 through an S1 interface. Although a single WTRU100 and three enbs 150 are shown in fig. 2, it should be apparent that any combination of wired and wireless devices may be included in the LTE wireless communication system/access network 70.

Fig. 3 is a block diagram of an LTE wireless communication system 200, which includes a WTRU100, an eNB150, and an MME/S-GW 180. As shown in fig. 3, the WTRU100, eNB150, and MME/S-GW180 are configured to select and reselect an UL primary carrier.

In addition to the components that may be found in a typical WTRU, the WTRU100 includes a processor 255 with an optional link memory 260, at least one transceiver 265, an optional battery 270, and an antenna 275. The processor 255 is configured to select and reselect a UL primary carrier. The transceiver 265 is in communication with the processor 255 and the antenna 275 to facilitate the transmission and reception of wireless communications. If a battery 270 is used in the WTRU100, the battery powers the transceiver 265 and the processor 255.

In addition to the components that may be found in a typical eNB, the eNB150 includes a processor 280 with an optional link memory 282, a transceiver 284, and an antenna 286. The processor 280 is configured to select and reselect an UL primary carrier. The transceiver 284 is in communication with the processor 280 and the antenna 286 to facilitate the transmission and reception of wireless communications. The eNB150 is connected to an MME/S-GW180, wherein the MME/S-GW180 includes a processor 288 with an optional link memory 290.

As shown in fig. 3, WTRU100 is in communication with node B150, and both are configured to perform the following method: in this method, UL transmissions from a WTRU100 are transmitted to a node-B150 using multiple UL carriers 190, and DL transmissions are processed with multiple carriers 195.

The network may assign at least one DL and/or at least one UL carrier as a primary DL carrier and a primary UL carrier, respectively. In multi-carrier operation, a WTRU may be configured to operate with two or more carriers (or also referred to as small frequencies or cells). Each of these carriers may have different characteristics and logical associations with the network and the WTRUs, and the operating frequencies may be grouped and referred to as primary or anchor carriers and supplemental or secondary carriers.

A "primary carrier" is a CC that provides control signaling (e.g., PDCCH scheduling) for UL and DL shared channel transmissions of UL and DL CC subsets.

UL primary carrier selection

The UL primary carrier may be used not only to combine HARQ feedback and CQI/PMI/RI reporting, but may also centralize SR, power headroom, and buffer status reporting in order to support multiple UL carriers. One HARQ entity may be assumed in each WTRU and have multiple HARQ processes for each CC.

The UL primary carrier may be selected by performing the following method. Assume that the WTRU is configured with y activated DL carriers (i.e., carriers 1D, 2D,...... ord, yD) and z activated UL carriers (i.e., carriers 1U, 2U,....... zU). If a WTRU is configured with independent PDCCH coding, a candidate PDCCH may be received on each of the y activated DL carriers.

The initial selection of the UL primary carrier may be performed in an initial Random Access Channel (RACH) procedure. Since there are multiple UL carriers, any one of the z activated UL carriers can act as a UL primary carrier. In a cell, the UL primary carrier may be either common or WTRU-specific.

One approach here may be to select the UL carrier that successfully completes the initial RACH procedure as the default UL primary carrier. The network may control which UL primary carrier to use by rejecting attempts on unintended UL carriers. Alternatively, the network may signal the intended or unintended UL carrier by system information on one or more DL carriers.

The WTRU may also perform initial UL primary carrier selection after or in conjunction with the cell selection procedure. Assuming that the RACH procedure and the information conveyed by the System Information Block (SIB) associated with the RACH procedure is similar to LTE, the WTRU may initiate the RACH procedure by camping on a common UL carrier common to all WTRUs of the network. The network may implicitly facilitate UL primary carrier selection by identifying PRACH resources only on a particular UL carrier.

Alternatively, the WTRU may determine the UL primary carrier explicitly or implicitly from RRC signaling. For example, the UL primary carrier may implicitly correspond to the first UL carrier provided in the RRC message for configuring the WTRU. Alternatively, the primary UL carrier may implicitly correspond to the UL carrier that provides the specific information element (e.g., related to feedback). Alternatively, as part of the modified RACH procedure, a new bit field in the RACH response message, or Radio Resource Control (RRC) or Medium Access Control (MAC) Control Element (CE) signaling in a message sent by the network, may indicate which of the z activated UL carriers serves as the UL primary carrier, which process may also be used for the remainder of the RACH procedure.

Another approach may be for the WTRU to select the UL carrier for the RACH procedure and act as the UL primary carrier based on the WTRU's Universal Subscriber Identity Module (USIM) modulo z1 (number of UL carriers) available based on system information broadcast in the cell. In this case, the system information may indicate the UL carrier and which of the UL carriers have PRACH resources available for selection.

The reselection or reconfiguration process (or unidirectional intra-cell handover) of the UL primary carrier may be performed according to one of several possible methods. eNB-initiated RRC procedures, new MAC CE messages, or PDCCH code points may trigger UL primary carrier changes specific to a WTRU. The process may also be part of a unidirectional intra-cell handover procedure in which only one or more UL carriers are affected and the DL carrier remains unchanged. This would compromise other WTRUs in the cell if the WTRU sent HARQ feedback or other information on the wrong UL channel, and therefore the process for changing the UL primary carrier must be very robust.

A unidirectional intra-cell handover procedure lacking RACH may be initiated by an RRC message to change from a first (i.e., initial) UL primary carrier to a second (i.e., new) UL primary carrier. Since the RRC message does not contain an explicit activation time, the usual approach is for the WTRU100 to send an SR message to indicate to the network that an RRC message has been received to trigger a unidirectional intra-cell handover and that the WTRU100 is changing (i.e., reselecting) to the second (i.e., new) UL primary carrier.

Fig. 4 is a flow diagram of a unidirectional intra-cell handover procedure 400 that lacks a RACH. In process 400, the WTRU100 is initially configured to use a particular UL carrier (e.g., 1U) as the first UL primary carrier (405). The WTRU100 receives a first RRC message in subframe k (400).

The WTRU100 then decodes the first RRC message and the message indicates that a unidirectional intra-cell handover should be initiated (415). The first RRC message may include the following fields: an Identification (ID) field for identifying the second (i.e., new) UL primary carrier, a field for indicating the PUCCH resources assigned for SR on the second UL primary carrier (optionally, it may be the same as the first UL primary carrier), and the message optionally includes a field for indicating that the first RRC message established unidirectional UL handover. This may be implicitly indicated by the presence of a specific field, e.g. a new UL primary carrier ID. The WTRU100 then sends the SR (i.e., subframe k +1) on the second UL primary carrier using the new resources indicated in the first RRC message or using the same resources as used by the first UL primary carrier (420). The WTRU100 may also send an SR on the first UL primary carrier. Operation on the second UL primary carrier is initiated either immediately after the SR is transmitted (i.e., subframe _ k +1+1), or after a predetermined delay after the SR is transmitted (425). The WTRU100 receives a UL grant (grant) requesting an acknowledgement (430), wherein the acknowledgement indicates that the first RRC message has been received. The WTRU100 then sends a second RRC message on the PUSCH allocated by the UL grant, acknowledging receipt of the first RRC message (435). Optionally, the above procedure for changing the first UL primary carrier is used if the WTRU100 determines that the timing advance applicable to the second UL primary carrier and the first UL primary carrier is the same. This determination may be based on the presence of an indication in the RRC message or MAC CE, or whether the second UL primary carrier is in the same frequency band as the first UL primary carrier, for example.

The unidirectional intra-cell handover procedure may be initiated by an RRC message, as in the previous procedure 400, but the WTRU100 receiving the RRC message initiates a RACH procedure on the new UL primary carrier. The RRC message may contain RACH dedicated resources.

Fig. 5 is a flow diagram of a one-way intra-cell handover procedure 500. In process 500, WTRU100 is initially configured to use a particular UL carrier (e.g., 1U) as the first UL primary carrier (505). The WTRU100 receives a first RRC message in subframe k (510). The first RRC message is then decoded by the WTRU100 and indicates that a unidirectional intra-cell handover should be initiated (515). The first RRC message may contain the following fields: an ID field to identify the second (i.e. new) UL primary carrier ID, a field to indicate the PUCCH resources assigned for SR on the second UL primary carrier (optionally, it may be the same as the first UL primary carrier), an optional field to indicate RACH dedicated resources (i.e. preamble), and a field to indicate that the message constitutes a unidirectional UL handover. This may be implicitly indicated by the presence of a specific field (e.g., a new UL primary carrier ID).

The WTRU100 then initiates a RACH procedure on the second UL primary carrier (520), whereby the WTRU receives a random access response message (subframe k _1+1) after the WTRU transmits a preamble. The random access response message may contain timing calibration or timing advance information. Alternatively, the WTRU100 may initiate a RACH procedure on the first UL primary carrier. Operation on the second UL primary carrier is initiated either immediately after the WTRU100 receives the random access response message (i.e., subframe _ k +1+1), or immediately after receiving the RACH message and a predetermined delay (525). The WTRU100 receives a UL grant requesting an acknowledgement (530) indicating that the first RRC message was received. The WTRU100 then sends a second RRC message on the PUSCH allocated by the UL grant, acknowledging receipt of the first RRC message (535). If the WTRU100 fails to receive the random access response message before the timer expires, the WTRU considers the unidirectional intra-cell handover to fail and reverts to the configuration before receiving the RRC message. Alternatively, the above procedure for changing the UL primary carrier may be used if the WTRU100 determines that the timing advance applicable to the second UL primary carrier and the first primary UL carrier is different. This determination may be based on the presence of an indication in the RRC message or MAC CE, or based on whether the second UL primary carrier is in the same frequency band as the first UL primary carrier, for example.

In any of the above procedures, the WTRU100 may determine the initial transmission power (e.g., PUCCH transmission) on the second UL primary carrier by using at least one of the following methods. The WTRU100 may determine the transmission power by applying an offset to the transmission power used in the first UL primary carrier. Alternatively, the WTRU100 may apply the same power control formula used in the first UL primary carrier with the same Path Loss (PL) parameter calculated, but with all or a subset of the other parameters specific to the second UL primary carrier. The offset or parameter may be obtained from a message (RRC or MAC) indicating that the first UL primary carrier should be changed.

The unidirectional UL handover procedure may be initiated by an RRC message, but after sending the RRC message, operation may still be on the previous UL primary carrier (during idle periods) until the WTRU100 sends an RRC acknowledgement on the PUSCH resource. The network may not schedule traffic in order to avoid collisions on the PUCCH resources to be used in the transfer.

Fig. 6 is a flow diagram of a one-way intra-cell handover procedure 600. As shown in fig. 6, a WTRU is initially configured to use a particular UL carrier (e.g., 1U) as a first UL primary carrier (605). The WTRU100 receives a first RRC message in subframe k (610).

The first RRC message is then decoded by the WTRU100 and indicates that a unidirectional intra-cell handover should be initiated. The first RRC message may include the following fields: an ID field to identify the second (i.e., new) UL primary carrier, a field to indicate the PUCCH resources assigned for SR on the second UL primary carrier (optionally, it may be the same as for the first UL primary carrier), and an RRC field to indicate that the message constitutes a unidirectional UL handover. This may be implicitly indicated by the presence of a specific field, e.g. a new UL primary carrier ID.

After waiting a predefined idle period to expire (620), which allows the WTRU100 to correctly receive and process RRC messages, the network schedules a UL grant to request an acknowledgement indicating that the first RRC message was received. The WTRU100 receives a UL grant (625) and sends a second RRC message on the PUSCH allocated by the UL grant, acknowledging receipt of the first RRC message (630). Operation on the second (i.e., new) UL primary carrier is initiated immediately after the second RRC message is sent, or may be initiated after a predetermined delay thereafter (635).

Figure 7 shows an example block diagram of a WTRU 700. The WTRU700 includes at least one antenna 705, a receiver 710, a transmitter 715, and a processor 720. Processor 720 may include a MAC layer 725 and a Physical (PHY) layer 730.

By implementing a unidirectional UL handover procedure, the UL Primary carrier can be changed using a new MAC CE command, which is then referred to as a MAC _ CE _ Primary _ Change command.

Fig. 8 is a flow diagram of a unidirectional UL handover procedure 800. Initially, WTRU700 is configured to use a particular UL carrier (e.g., 1U) as the first UL primary carrier (805). In subframe k, the WTRU700 receives a transport block including a MAC CE (MAC _ CE _ Primary _ Change command) indicating a UL Primary carrier Change (810). The MAC _ CE _ Primary _ Change command is processed by the MAC layer 725, and then informs the PHY layer 730 that the new UL Primary carrier (e.g., 2U) will be in subframe _ k +4+ n (815), where n is a predefined number typically equal to (or greater than) 1. The MAC _ CEP _ rimary _ Change command may include a bit field indicating a new UL primary carrier ID. In subframe + k +4, the PHY layer 730 sends an Acknowledgement (ACK) using the still valid UL primary carrier 1U (820), and the network receiving the ACK knows from the HARQ feedback that the WTRU700 may start operating on the new UL primary carrier 2U. For robustness, the network may send another MAC _ CE _ Primary _ Change command to confirm that the received ACK is not a false positive. Further, if no ACK is received, the same processing is performed. During this transition time, the network may avoid assigning the same PUCCH resources of the two UL carriers to other WTRUs. The WTRU700 processes the same MAC _ CEP _ rimary _ Change previously processed in subframe _ k +4+ n. Since the carrier ID bit field is the same as the existing UL primary carrier, the MAC layer 725 does not perform any processing on the MAC _ CEP _ rimary _ Change. In subframe _ k +4+ n +4, the PHY layer 730 sends an ACK using the new UL primary carrier 2U (830). The network receives the ACK to confirm that the WTRU's primary carrier has changed.

WTRU-automatically performed UL primary carrier selection

The WTRU700 may automatically initiate the UL primary carrier reselection procedure. The trigger criteria may be associated with an event indicating a failure of an existing UL primary carrier. The WTRU700 performs procedures similar to the initial UL primary carrier assignment procedure using PRACH described above.

The above method takes the form of a simplified intra-cell reselection or handover procedure. The cell providing the security input parameters does not necessarily need to be changed and the user plane protocols (packet data convergence protocol (PDCP) and Radio Link Control (RLC)) do not necessarily need to be re-established. The UL primary carrier may be switched and possibly the DL primary carrier (or set of UL and DL carriers). One aspect in contrast to normal handover is that a main reselection or handover can only be performed in one direction (UL or DL).

The new UL primary carrier may or may not be part of a previously configured UL carrier. If the new UL primary carrier is part of the existing UL carrier set for use by the WTRU700, the signaling and assignment process may be simplified by using PDCCH/PUCCH or MAC CE signaling. If the new primary carrier is not part of the RRC dedicated existing UL carrier set or system information, signaling may be required to provide detailed carrier information.

Furthermore, some approaches define explicit time boundaries when switching to dedicated PUCCH resources should occur. This allows for maintaining DL traffic activity during the transition even if there are two or more HARQ feedbacks into the UL primary carrier. For example, in process 400, all DL HARQ feedback is conveyed to the previous UL primary carrier until an SR is sent on the new UL primary carrier indicating that the RRC message was correctly received.

The DL primary PDCCH may include DL primary associated PDCCH coding or DL primary independent PDCCH coding. In the DL primary PDCCH, all PDCCHs are transmitted in a primary carrier regardless of whether the PDCCHs are independently coded or jointly coded.

If a DL primary carrier is indicated, an UL primary carrier may be determined according to information of the DL primary carrier. In other words, the UL primary carrier may be associated with the DL primary carrier such that the DL primary carrier is mapped to the UL primary carrier using the mapping rule. If a DL primary carrier is indicated, there is no need to signal the UL primary carrier separately.

For symmetric UL/DL carriers, a one-to-one mapping is defined or specified between the UL primary carrier and the DL primary carrier. For example, the mapping rule may be: the DL primary carrier (DL carrier x) is associated with the UL primary carrier (UL carrier y).

Typically, y ═ f (x), where f () is a fixed function that correlates UL and DL primary carriers. If f () is known, the method for determining the UL primary carrier is applicable to a symmetric number of CCs in UL and DL.

For asymmetric UL/DL carriers with more DL carriers than UL carriers, the mapping rule f () may be: if the DL primary carrier is DL carrier x1 or x2, the UL primary carrier is UL carrier y 1; if the DL primary carrier is DL carrier x3 or x4, the UL primary carrier is UL carrier y2, and so on.

Alternatively, the DL carrier may be symmetric to the UL carrier in order to determine the UL primary carrier. In this method, a subset of DL carriers is to be selected, and the number of DL carriers in the selected subset of carriers is equal to the number of UL carriers. Only DL carriers in the subset of DL carriers are allowed to be DL primary carriers. The mapping rules used here for the DL/UL primary carriers are similar to the rules that can be used in the symmetric UL/DL carrier paradigm. The DL primary carrier subset may be signaled, configured, or predetermined.

This mapping rule may be generalized and other mappings and associations between UL and DL primary carriers may be used. The mapping rule may be signaled, configured, or predetermined.

For asymmetric UL/DL carriers with more UL carriers than DL carriers, the following rules or methods may be used: the UL carrier may be symmetric to the DL carrier in order to determine the UL primary carrier.

In the method, a subset of UL carriers is to be selected, and the number of UL carriers in the selected subset of carriers is equal to the number of DL carriers. Only the UL carriers in the subset of carriers are allowed to become UL primary carriers. The mapping rules used here for the DL/UL subcarriers are similar to those in the symmetric UL/DL carrier example that can be used as described above. The UL primary carrier subset may be signaled, configured, or predetermined.

Alternatively, the UL primary carrier may be indicated in a similar manner as described above in the DL non-primary independent PDCCH coding.

Additional variations of the foregoing method may also be proposed if the DL primary associated PDCCH method is used. If no change in the DL primary carrier is identified, the same solution as for the non-primary independent coding can be applied.

In joint PDCCH coding, a single PDCCH will be received, where the PDCCH defines multiple DL or UL assignments on the PDSCH of multiple DL carriers (carriers 1D, 2D, carriers 1U, 2U. By definition, if such an assignment is received in subframe _ n-4, only one starting CCE of PDCCH is defined. The starting CCE may be used to define a first PUCCH resource that would carry the combined HARQ feedback in subframe _ n as described previously. If more than one PUCCH resource is required, the subsequent PUCCH resources are used according to the cyclic shift. Furthermore, in contrast to LTE, the combined HARQ feedback may be sent on the PUCCH even though the WTRU700 sends data on the UL-SCH in the same subframe and the same slot.

In another approach, dynamic selection is performed on the UL carrier used for DL-SCH feedback. In this approach, feedback related to a certain DL-SCH (including HARQ ACK/Negative Acknowledgement (NACK), CQI, PMI, and RI) as well as other information such as SR may be transmitted on a dynamic basis on different UL CCs. For example, feedback for a specified DL-SCH may always be transmitted from the PUCCH of a specified UL CC if PUSCH transmission has not occurred on any UL CC, whereas feedback is provided on the PUSCH of one of the UL CCs if PUSCH transmission has occurred on at least one UL CC.

More generally, if there is one allowed UL CC with PUSCH transmission on a specified subframe, the selection result for selecting the UL CC to transmit the information in the specified subframe may be transmitted on this allowed UL CC. The set of allowed UL CCs may be signaled by higher layers on a semi-static basis. If there is more than one such allowed UL CC, the WTRU700 may choose randomly among the allowed UL CCs. Alternatively, the UL CCs may be ordered in order according to priority (such ordering may be signaled by higher layers). This information may be transmitted on the PUCCH of a predetermined UL CC (which may be signaled by higher layers) if there is no UL CC transmitting PUSCH transmission in the subframe. Alternatively, if a UL CC that provides feedback for another DL-SCH is not yet available, information may be transmitted on the PUCCH of the UL CC.

The process of using PUCCH for a certain UL CC may be specified by setting a rank between different DL-SCHs that must use the process.

If there is no UL CC whose PUCCH is not used by another DL-SCH, the information can be multiplexed with information related to the other DL-SCH on the same PUCCH of the UL CC.

Aggregation of UL control signaling

In an independent PDCCH-coded non-primary carrier, different PDCCHs may be separately and independently received on one or more DL carriers (i.e., carriers 1D, 2D, carrier 1D, carrier 2D, carrier 1D). In the UL primary carrier approach, multiple HARQ feedbacks derived from the received PDSCH are combined and transmitted on the PUSCH resources of the configured UL primary carrier. Furthermore, in contrast to LTE, the combined HARQ feedback may be sent on the PUCCH even if the WTRU sends data on the same UL-SCH in the same subframe and the same carrier (i.e., UL data and control may be transmitted in parallel on the same subframe of the same carrier).

In the first approach, the DL carriers (i.e., carriers 1D, 2D,... D, yD) are ordered according to rules or information sent by higher layers. For example, the WTRU700 may rank the DL carriers in order from highest priority to lowest priority, with carrier 1D having the highest priority and carrier yD having the lowest priority. One or more PDCCHs may be received at subframe n-4. Then, for the highest priority carrier on which PDCCH is received, the starting CCE for that carrier will be used to derive the PUCCH resource used to carry HARQ feedback. If more than one PUCCH resource is required, additional PUCCH resources according to the cyclic shift are used.

Fig. 9 is a flow diagram of a process 900 for sending HARQ feedback. As shown in fig. 9, the WTRU700 is initially configured to use a particular UL carrier (e.g., 1U) as the UL primary carrier (905). The DL carriers are then arranged in an ordered list (e.g., 1D to yD). In subframe _ n-4, the WTRU700 searches for PDCCH candidates in the DL carriers (1D, 2D, 1.... yD) of the WTRU-specific DL search space (910). If the PDCCH is assumed to match a WTRU radio network temporary identity (C-RNTI) on several DL carriers with a starting CCE _2n for carrier 2D, examples of possible PDSCH decoding results may be: the 2D, 3D, and 5D ACKs indicate that the PDSCH in carriers 2D and 5D was successfully received, and the PDSCH in carrier 3D was not successfully received (915). In subframe _ n, the WTRU700 sends feedback (i.e., two ACKs/NACKs, ACK and NACK corresponding to carriers 2D and 3D, respectively) via the UL primary carrier and on PUCCH resources determined with the starting address CCE _2n using PUCCH format 1b (920). The carrier 5D of the third highest priority uses a PUCCH resource immediately following the previous PUCCH resource according to the cyclic shift. In this case, the ACK corresponding to carrier 5D is transmitted with format 1 a.

Alternatively, to reduce the impact of ACK in the event of a false PDCCH detection, the WTRU700 may send a Discontinuous Transmission (DTX) value for the carrier that did not receive PDCCH if other carriers receive PDCCH. For example, a DTX indication may be sent when a carrier does not receive a PDCCH in subframe _ n-4 but is between the highest priority carrier on which the PDCCH was received and the lowest priority carrier on which the carrier was also received. In the previous example, the WTRU700 sends the value of ACK/NACK in subframe _ n, followed by DTX/NACK on two (2) PUCCH resources (both using format 1 b).

In the second approach, there is no need to order between carriers. In subframe _ n-4, one or more PDCCHs will be received. For each carrier Dn that receives a PDCCH with a matching CRC, ACK/NACK with PUCCH resource CCE (N) + N PUCCH (N) is used, where CCE (N) is the starting CCE of the PDCCH received on carrier Dn, then N PUCCH (N) is the offset determined by providing N PUCCH (N) for each DL carrier by the higher layer, or by defining N PUCCH (N) as the sum of N PUCCH (1) + NCCE (2) +. + NCCE (N), where N PUCCH (1) is provided by the higher layer and NCCE (N) is the total number of CCEs on carrier Dn.

According to a second approach, the WTRU700 may use format 1a for each carrier that needs to send a single ACK/NACK (single codeword) and format 1b for each carrier that needs to send two ACK/NACKs (two codewords).

In the third method, no ordering is required between carriers, but carriers may be paired with each other. For example, carrier D1 may be paired with carrier D3. This third method can be used when at most one codeword requires an ACK or NACK from each carrier. In subframe _ n-4, one or more PDCCHs will be received. For each pair of carriers (Dn1, Dn2) on which PDCCH with matching CRC is received on at least one carrier (with at most one codeword), used is ACK/NACK for PUCCH resources CCE (N1) + N _ PUCCH (N1), where CCE (N1) is the starting CCE of PDCCH received on carrier Dn1 and N _ PUCCH (N1) is an offset determined by providing N _ PUCCH (N1) by higher layers for each DL carrier or an offset determined by defining N _ PUCCH (N1) as the sum of N _ PUCCH (1) + NCCE (2) +. + NCCE (N), where N _ PUCCH (1) is provided by higher layers and NCCE (N) is the total number of CCEs on carriers Dn.

With this approach, the WTRU700 may use format 1b with a two-valued ACK/DTX/NACK code point corresponding to the ACK/DTX/NACK feedback to be sent for carriers Dn1 and Dn.

The second method may be used in combination with the third method. The second method may be used whenever more than one codeword needs to be transmitted from either carrier of a pair of carriers from which data is received.

The WTRU may send periodic CQI/PMI/RI reports for each active DL carrier (carriers 1D, 2D, carrier. Furthermore, in contrast to LTE, the combined periodic CQI/PMI/RI reports may be sent on the PUCCH even though WTRU700 sends data on the UL-SCH in the same subframe and the same carrier. The higher layer will configure the reporting interval for each activated DL carrier and the PUCCH format to be used. The CQI information periodically transmitted on the determined PUCCH resources of the UL primary carrier may represent one individual carrier at a time. The carrier ID information need not be associated with CQI reports. On PUCCH, periodic CQI/PMI/RI reporting depends on the DRX state of the respective DL carrier being reported. Thus, the combined reports may not have to be reported all the time on all carriers, when one or more DL carriers are in DRX state, the reporting of each single carrier may be skipped.

The periodic CQI/PMI/RI may be transmitted over PUSCH resources if it must be reported in a designated subframe and PUSCH allocation on the same carrier or a different carrier is available.

When the SR is triggered, the SR may be transmitted through a PUCCH or a PRACH. When SR is triggered on PUCCH or PRACH, the SR is transmitted on the UL primary carrier.

Alternatively, higher layers may reserve PUCCH resources for the UL non-primary carrier for the WTRU700 and the WTRU700 may use the resources to trigger certain procedures, such as a primary carrier change in UL or DL. Further, MAC Protocol Data Units (PDUs) may be transmitted on the UL primary carrier when reporting criteria for Buffer Status Reporting (BSR) and/or Power Headroom Reporting (PHR) are triggered.

In the initial setting of the UL carrier implemented by the RRC message, it should be allowed that a dedicated PUCCH resource for SR is not designated for the UL non-primary carrier and a dedicated PUCCH resource for SR is logically designated for the UL carrier.

In the case of multiple UL carriers, especially where one UL carrier (i.e., the UL primary carrier) is used to carry HARQ feedback and CQI/PMI/RI feedback for multiple DL carriers, it is possible that activity on the other UL carriers is mostly limited to UL traffic (limited control data). Therefore, it would be valuable if Sounding Reference Signal (SRS) transmission on non-primary carriers could be stopped implicitly without explicit MAC CE or RRC signaling. For example, the WTRU700 may stop SRS transmission on a UL CC once the UL inactivity timer expires, which is restarted whenever there is a PUSCH transmission on this UL CC.

The WTRU700 may resume SRS transmission on the designated UL carrier when the UL data buffer associated with the designated UL carrier reaches a certain threshold. In addition, the network that receives the SRS again may actively transmit the UL grant. This provides the WTRU700 with another mechanism for requesting UL grants. The mechanism is equally applicable to the following primary carriers: in the primary carrier, activity may be affected by UL traffic and it is possible to implicitly stop SRS transmission on the primary carrier without explicit MAC CE or RRC signaling. This is because even if there are HARQ feedback and CQI/PMI/RI feedback on the primary carrier, these feedbacks are confined in the PUCCH resources, and a demodulation reference signal (DM RS) for PUCCH will be used for channel quality estimation instead of using SRS. Thus, SRS transmission may be turned off if the UL data buffer associated with the primary carrier is below a certain threshold, and SRS transmission may be resumed if the UL data buffer associated with the primary carrier is above a certain threshold.

Assuming that the WTRU700 is configured with multiple DL carriers (1D, 2D, 1.... yD), the relative Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ) levels of each active DL carrier may be different, thereby allowing the WTRU700 to be configured with new measurement reporting events that compare the relative signal quality of each carrier. For example, a measurement reporting event may be triggered if the RSRQ of the DL primary carrier is below a certain threshold and the RSRQ of one of the DL non-primary carrier portions in the candidate set appears to be a certain amount (e.g., in dB) greater than the current RSRQ of the primary carrier.

The candidate set may be a different set than the currently active set of DL carriers for WTRU 700. This candidate set may be signaled by the network, which also takes into account other factors, such as the control area load in the cell for each carrier.

Referring again to fig. 7, the WTRU700 is configured to reselect an Uplink (UL) primary carrier. Processor 720 may be configured to use the particular UL carrier as the first UL primary carrier. Receiver 720 may be configured to receive and decode the first RRC message, and receive the UL grant. The transmitter 715 may be configured to transmit the SR on the second UL primary carrier and transmit a second RRC message on the PUSCH of the UL grant allocation, acknowledging receipt of the first RRC message.

The transmitter 715 may be configured to transmit a HARQ ACK or NACK over the second UL primary carrier to provide feedback relating to the particular DL-SCH.

Feedback related to the specific DL-SCH may be transmitted through the PUCCH of the second UL primary carrier.

Multiple HARQ feedback derived from the received PDSCH may be combined and transmitted on PUCCH resources of the second UL primary carrier.

The first RRC message may indicate that a unidirectional intra-cell handover should be initiated.

The first RRC message may include a field identifying the second UL primary carrier.

The first RRC message may include a field to indicate the assigned PUCCH resource.

The first RRC message may include an RRC field indicating that the first RRC message establishes the unidirectional UL handover.

The SR may be transmitted on the second UL primary carrier by using the new resources indicated in the first RRC message.

The processor in WTRU700 may be configured to use a particular UL carrier as the UL primary carrier and initiate a RACH procedure on a second UL primary carrier. Receiver 710 can be configured to receive and decode a first RRC message, receive a random access response message, and receive an UL grant. The transmitter 715 may be configured to transmit a preamble and transmit a second RRC message on the PUSCH allocated by the UL grant in response to receipt of the first RRC message.

The first RRC message may include a field indicating RACH dedicated resources.

The RACH message may include timing alignment or timing advance information.

Receiver 710 may be configured to receive a MAC CE primary change command. Processor 720 may be configured to use a particular UL carrier as the first UL primary carrier. PHY layer 730 may be configured to send a first ACK via a first UL primary carrier in a first subframe and a second ACK via a second UL primary carrier in a second subframe. The MAC layer 725 may be configured to process the MAC CE primary change command, advertise the location of the second UL primary carrier to the PHY, and process the same MAC CE primary change command as the previously processed MAC CE primary change command. PHY layer 730 and MAC layer 725 may reside in the processor.

Examples

1. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

the WTRU is configured to use a particular UL carrier as the first UL primary carrier.

2. The method of embodiment 1, further comprising:

receiving a first Radio Resource Control (RRC) message;

decoding the first RRC message;

transmitting a Scheduling Request (SR) on a second UL primary carrier;

initiating an operation on a second UL primary carrier;

receiving an UL grant; and

transmitting a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

3. The method of embodiment 2, further comprising:

transmitting a hybrid automatic repeat request (HARQ) Acknowledgement (ACK) or Negative Acknowledgement (NACK) over a second UL primary carrier to provide feedback relating to a particular downlink shared channel (DL-SCH).

4. The method of embodiment 2, further comprising:

a Channel Quality Indicator (CQI) is transmitted over the second UL primary carrier to provide feedback relating to a particular downlink shared channel (DL-SCH).

5. The method of embodiment 2 wherein feedback relating to a specific downlink shared channel (DL-SCH) is transmitted over a Physical Uplink Control Channel (PUCCH) of the second UL primary carrier.

6. A method as in any of embodiments 2-5 wherein multiple hybrid automatic repeat request (HARQ) feedbacks derived from a received Physical Downlink Shared Channel (PDSCH) are combined and transmitted on Physical Uplink Control Channel (PUCCH) resources of a second UL primary carrier.

7. The method as in any embodiments 2-6, wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

8. The method as in any embodiments 2-6 wherein the first RRC message comprises a field identifying the second UL primary carrier.

9. A method as in any of embodiments 2-6 wherein the first RRC message comprises a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

10. The method as in any embodiments 2-6 wherein the first RRC message comprises an RRC field indicating that the first RRC message established a unidirectional UL handover.

11. The method as in any embodiments 2-10, wherein the SR is transmitted on the second UL primary carrier using new resources indicated in the first RRC message.

12. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring a WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a first Radio Resource Control (RRC) message;

decoding the first RRC message;

initiating a Random Access Channel (RACH) procedure on a second UL primary carrier;

transmitting a preamble;

receiving a random access response message;

initiating an operation on a second UL primary carrier;

receiving an UL grant; and

transmitting a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

13. The method as in embodiment 12 wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

14. The method as in embodiment 12 wherein the first RRC message includes a field identifying the second UL primary carrier.

15. The method of embodiment 12 wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

16. The method of embodiment 12 wherein the first RRC message includes a field indicating RACH dedicated resources.

17. The method of embodiment 12 wherein the first RRC message includes an RRC field indicating that the first RRC message established a unidirectional UL handover.

18. The method as in any one of embodiments 12-17 wherein the RACH message comprises timing alignment or timing advance information.

19. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring a WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a first Radio Resource Control (RRC) message;

decoding the first RRC message;

waiting for a predefined idle period to expire;

receiving an UL grant;

transmitting a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant; and

initiating operation on the second UL primary carrier.

20. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring a WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a Medium Access Control (MAC) Control Element (CE) primary change command;

the MAC layer in the WTRU processes the MAC CE primary change command and informs a Physical (PHY) layer in the WTRU of the location of the second UL primary carrier;

in a first subframe, the PHY layer transmits a first Acknowledgement (ACK) via a first UL primary carrier;

the MAC layer processes the MAC CE main change command which is the same as the MAC CE main change command processed previously; and

in the second subframe, the PHY layer sends a second ACK via the second UL primary carrier.

21. A wireless transmit/receive unit (WTRU) for reselecting an Uplink (UL) primary carrier, the WTRU comprising:

a processor configured to use a specific UL as a first UL primary carrier;

a receiver configured to receive and decode a first Radio Resource Control (RRC) message and receive an UL grant; and

a transmitter configured to transmit a Scheduling Request (SR) on a second UL primary carrier and transmit a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

22. The WTRU of embodiment 21, further comprising:

a transmitter configured to transmit a hybrid automatic repeat request (HARQ) Acknowledgement (ACK) or Negative Acknowledgement (NACK) over a second UL primary carrier to provide feedback relating to a particular downlink shared channel (DL-SCH).

23. The WTRU of embodiment 21, further comprising:

a transmitter configured to transmit a Channel Quality Indicator (CQI) over a second UL primary carrier to provide feedback related to a specific downlink shared channel (DL-SCH).

24. The WTRU of embodiment 21 wherein feedback related to a specific downlink shared channel (DL-SCH) is transmitted through a Physical Uplink Control Channel (PUCCH) of a second UL primary carrier.

25. The WTRU as in any one of embodiments 22-24 wherein a plurality of hybrid automatic repeat request (HARQ) feedbacks derived from a received Physical Downlink Shared Channel (PDSCH) are combined and transmitted on Physical Uplink Control Channel (PUCCH) resources of a second UL primary carrier.

26. The WTRU as in any one of embodiments 22-24, wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

27. A WTRU as in any of embodiments 22-25 wherein the first RRC message includes a field identifying the second UL primary carrier.

28. A WTRU as in any of embodiments 22-25 wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

29. The WTRU as in any one of embodiments 22-25, wherein the first RRC message includes an RRC field indicating that the first RRC message established a unidirectional UL handover.

30. The WTRU as in any of embodiments 22-29, wherein the SR is sent on the second UL primary carrier using the new resource indicated in the first RRC message.

31. A wireless transmit/receive unit (WTRU) for reselecting an Uplink (UL) primary carrier, the WTRU comprising:

a processor configured to configure a WTRU to use a particular UL carrier as a UL primary carrier and to initiate a Random Access Channel (RACH) procedure on a second UL primary carrier;

a receiver configured to receive and decode a first Radio Resource Control (RRC) message, receive a random access response message, and receive an UL grant; and

a transmitter configured to transmit a preamble and to transmit a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

32. The WTRU of embodiment 31 wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

33. The WTRU of embodiment 31 wherein the first RRC message includes a field identifying the second UL primary carrier.

34. The WTRU of embodiment 31 wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

35. The WTRU of embodiment 31 wherein the first RRC message includes a field indicating RACH dedicated resources.

36. The WTRU of embodiment 31 wherein the first RRC message includes an RRC field indicating that the first RRC message establishes the unidirectional UL handover.

37. The WTRU as in any one of embodiments 31-36 wherein the RACH message includes timing alignment or timing advance information.

38. A wireless transmit/receive unit (WTRU) for reselecting an Uplink (UL) primary carrier, the WTRU comprising:

a receiver configured to receive a Medium Access Control (MAC) Control Element (CE) primary change command;

a processor configured to use a specific UL carrier as a first UL primary carrier;

a Physical (PHY) layer configured to transmit a first Acknowledgement (ACK) via a first UL primary carrier in a first subframe and a second ACK via a second UL primary carrier in a second subframe; and

a Medium Access Control (MAC) layer configured to process the MAC CE primary change command, inform the PHY layer of the location of the second UL primary carrier, and process the MAC CE primary change command that is the same as the previously processed MAC CE primary change command.

39. The WTRU of embodiment 38 wherein the PHY layer and the MAC layer reside in a processor.

Although the features and elements of the present invention are described in the particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements. The methods or flow charts provided herein may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of the computer-readable storage medium include Read Only Memory (ROM), Random Access Memory (RAM), registers, buffer memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs).

For example, suitable processors include: a general-purpose processor, a special-purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any Integrated Circuit (IC), and/or a state machine.

A processor in association with software may be used to implement a radio frequency transceiver for use in a Wireless Transmit Receive Unit (WTRU), User Equipment (UE), terminal, base station, Radio Network Controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a video phone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, and BluetoothA module, a Frequency Modulation (FM) radio unit, a Liquid Crystal Display (LCD) display unit, an Organic Light Emitting Diode (OLED) display unit, a digital music player, a media player, a video game player module, an internet browser, and/or any Wireless Local Area Network (WLAN) or Ultra Wideband (UWB) module.

Claims (38)

1. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring the WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a first Radio Resource Control (RRC) message;

decoding the first RRC message;

transmitting a Scheduling Request (SR) on a second UL primary carrier;

initiating an operation on a second UL primary carrier;

receiving an UL grant; and

transmitting a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

2. The method of claim 1, further comprising:

transmitting a hybrid automatic repeat request (HARQ) Acknowledgement (ACK) or Negative Acknowledgement (NACK) over the second UL primary carrier to provide feedback relating to a particular downlink shared channel (DL-SCH).

3. The method of claim 1, further comprising:

transmitting a Channel Quality Indicator (CQI) over the second UL primary carrier to provide feedback related to a particular downlink shared channel (DL-SCH).

4. The method of claim 1, wherein feedback related to a specific downlink shared channel (DL-SCH) is transmitted over a Physical Uplink Control Channel (PUCCH) of the second UL primary carrier.

5. The method of claim 1, wherein multiple hybrid automatic repeat request (HARQ) feedbacks originating from a received Physical Downlink Shared Channel (PDSCH) are combined and transmitted on Physical Uplink Control Channel (PUCCH) resources of the second UL primary carrier.

6. The method of claim 1, wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

7. The method of claim 1, wherein the first RRC message includes a field identifying the second UL primary carrier.

8. The method of claim 1, wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

9. The method of claim 1, wherein the first RRC message includes an RRC field indicating that the first RRC message established a unidirectional UL handover.

10. The method of claim 1, wherein the SR is transmitted on the second UL primary carrier using new resources indicated in the first RRC message.

11. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring the WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a first Radio Resource Control (RRC) message;

decoding the first RRC message;

initiating a Random Access Channel (RACH) procedure on a second UL primary carrier;

transmitting a preamble;

receiving a random access response message;

initiating an operation on the second UL primary carrier;

receiving an UL grant; and

transmitting a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

12. The method of claim 11, wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

13. The method of claim 11, wherein the first RRC message includes a field identifying the second UL primary carrier.

14. The method of claim 11, wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

15. The method of claim 11, wherein the first RRC message includes a field indicating RACH dedicated resources.

16. The method of claim 11, wherein the first RRC message includes an RRC field indicating that the first RRC message establishes a unidirectional UL handover.

17. The method of claim 11, wherein the RACH message includes timing alignment or timing advance information.

18. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring the WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a first Radio Resource Control (RRC) message;

decoding the first RRC message;

waiting for a predefined idle period to expire;

receiving an UL grant;

transmitting a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant; and

initiating operation on the second UL primary carrier.

19. A method implemented by a wireless transmit/receive unit (WTRU) of reselecting an Uplink (UL) primary carrier, the method comprising:

configuring the WTRU to use a particular UL carrier as a first UL primary carrier;

receiving a Medium Access Control (MAC) Control Element (CE) primary change command;

the MAC layer in the WTRU processing the MAC CE primary change command and informing a Physical (PHY) layer in the WTRU of a location of a second UL primary carrier;

in a first subframe, the PHY layer sends a first Acknowledgement (ACK) via the first UL primary carrier;

the MAC layer processes the MAC CE main change command which is the same as the MAC CE main change command processed previously; and

in a second subframe, the PHY layer sends a second ACK via the second UL primary carrier.

20. A wireless transmit/receive unit (WTRU) for reselecting an Uplink (UL) primary carrier, the WTRU comprising:

a processor configured to use a specific UL as a first UL primary carrier;

a receiver configured to receive and decode a first Radio Resource Control (RRC) message and receive an UL grant; and

a transmitter configured to transmit a Scheduling Request (SR) on a second UL primary carrier and to transmit a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

21. The WTRU of claim 20, further comprising:

a transmitter configured to transmit a hybrid automatic repeat request (HARQ) Acknowledgement (ACK) or Negative Acknowledgement (NACK) over the second UL primary carrier to provide feedback relating to a particular downlink shared channel (DL-SCH).

22. The WTRU of claim 20, further comprising:

a transmitter configured to transmit a Channel Quality Indicator (CQI) over the second UL primary carrier to provide feedback related to a particular downlink shared channel (DL-SCH).

23. The WTRU of claim 20 wherein feedback related to a specific downlink shared channel (DL-SCH) is transmitted through a Physical Uplink Control Channel (PUCCH) of the second UL primary carrier.

24. The WTRU of claim 20 wherein a plurality of hybrid automatic repeat request (HARQ) feedbacks derived from a received Physical Downlink Shared Channel (PDSCH) are combined and transmitted on Physical Uplink Control Channel (PUCCH) resources of the second UL primary carrier.

25. The WTRU of claim 20 wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

26. The WTRU of claim 20 wherein the first RRC message includes a field identifying the second UL primary carrier.

27. The WTRU of claim 20 wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

28. The WTRU of claim 20 wherein the first RRC message includes an RRC field indicating that the first RRC message establishes a unidirectional UL handover.

29. The WTRU of claim 20 wherein the SR is sent on the second UL primary carrier using a new resource indicated in the first RRC message.

30. A wireless transmit/receive unit (WTRU) for reselecting an Uplink (UL) primary carrier, the WTRU comprising:

a processor configured to configure the WTRU to use a particular UL carrier as a UL primary carrier and to initiate a Random Access Channel (RACH) procedure on a second UL primary carrier;

a receiver configured to receive and decode a first Radio Resource Control (RRC) message, receive a random access response message, and receive an UL grant; and

a transmitter configured to transmit a preamble and to transmit a second RRC message acknowledging receipt of the first RRC message on a Physical Uplink Shared Channel (PUSCH) allocated by the UL grant.

31. The WTRU of claim 30 wherein the first RRC message indicates that a unidirectional intra-cell handover should be initiated.

32. The WTRU of claim 30 wherein the first RRC message includes a field identifying the second UL primary carrier.

33. The WTRU of claim 30 wherein the first RRC message includes a field indicating an assigned Physical Uplink Control Channel (PUCCH) resource.

34. The WTRU of claim 30 wherein the first RRC message includes a field indicating RACH dedicated resources.

35. The WTRU of claim 30 wherein the first RRC message includes an RRC field indicating that the first RRC message establishes a unidirectional UL handover.

36. The WTRU of claim 30 wherein the RACH message includes timing alignment or timing advance information.

37. A wireless transmit/receive unit (WTRU) for reselecting an Uplink (UL) primary carrier, the WTRU comprising:

a receiver configured to receive a Medium Access Control (MAC) Control Element (CE) primary change command;

a processor configured to use a specific UL carrier as a first UL primary carrier;

a Physical (PHY) layer configured to transmit a first Acknowledgement (ACK) via the first UL primary carrier in a first subframe and a second ACK via a second UL primary carrier in a second subframe; and

a Medium Access Control (MAC) layer configured to process the MAC CE primary change command, inform the PHY layer of the location of the second UL primary carrier, and process the same MAC CE primary change command as a previously processed MAC CE primary change command.

38. The WTRU of claim 37 wherein the PHY layer and the MAC layer are present in the processor.