HK1165144A - Method and apparatus for carrier assignment, configuration and switching for multicarrier wireless communications - Google Patents

Description

Method and apparatus for carrier allocation, configuration and switching for multi-carrier wireless communication

Cross Reference to Related Applications

The present application claims the benefit of U.S. patent application No.61/160,513 filed on 3/16/2009 and U.S. patent application No.61/160,106 filed on 3/13/2009, which are incorporated by reference herein.

Technical Field

The present application relates to wireless communications.

Background

In multicarrier communication, reporting Downlink (DL) control information on the Uplink (UL) is typically done for one DL carrier at a time. Therefore, existing multicarrier communication systems lack techniques for reporting control information on the UL for multiple parallel DL carriers.

An example multi-carrier wireless communication system is the third generation partnership project (3GPP) Long Term Evolution (LTE) system, which has been introduced into 3GPP release 8 (R8). The lte dl transmission scheme is based on an Orthogonal Frequency Division Multiple Access (OFDMA) air interface. In accordance with OFDMA, a wireless transmit/receive unit (WTRU) may be assigned by an evolved node-B to receive data anywhere over the entire LTE transmission bandwidth. For the LTE Uplink (UL) direction, Single Carrier (SC) transmission is used based on discrete fourier transform spread OFDMA (DFT-S-OFDMA), or equivalently based on single carrier frequency division multiple access (SC-FDMA). A WTRU in the UL may transmit only on a limited but contiguous set of allocated subcarriers in an FDMA arrangement. Fig. 1 illustrates mapping of transport blocks 102 into LTE carriers 110 for UL or DL transmission. Layer 1(L1)106 receives information from the hybrid automatic repeat request (HARQ) entity 104 and the scheduler 108 and uses the information to allocate transport blocks 102 into LTE carriers 110. As shown in fig. 1, an UL or DL LTE carrier 110 or just carrier 110 is composed of multiple subcarriers 112. The eNB may simultaneously receive a composite UL signal from one or more WTRUs in the entire transmission bandwidth, where each WTRU transmits on a subset of the available transmission bandwidth or subcarriers.

LTE-advanced (LTE-a) is being developed by the 3GPP standardization body to further improve the achievable throughput and coverage of LTE-based radio access systems and to meet the international mobile telecommunications advanced (IMT) requirements of 1Gbps and 500Mbps in the DL and UL directions, respectively. Proposed in the improvement for LTE-a is carrier aggregation and support for flexible bandwidth placement. LTE-a proposes a restriction to allow DL and UL transmission bandwidths to exceed 20MHz in R8LTE, for example allowing 40MHz or 100MHz bandwidths. In this case, the carrier may occupy the entire frequency block.

LTE-a proposes to allow more flexible use of the available paired spectrum and is not restricted to operating in symmetric and paired FDD modes as in R8 LTE. LTE-a proposes to allow an asymmetric configuration, where a DL bandwidth such as 10MHz can be paired with a UL bandwidth of 5 MHz. Furthermore, LTE-a proposes a composite aggregate transmission bandwidth, wherein the transmission bandwidth may be backward compatible with LTE. For example, the DL may comprise a first 20MHz carrier and a second 10MHz carrier, wherein the second 10MHz carrier is paired with an UL 20MHz carrier. Carriers that are transmitted in parallel in the same UL or DL direction are referred to as component carriers. The composite aggregate transmission bandwidth of the component carriers is not necessarily contiguous in the frequency domain. For example, the first 10MHz component carrier may be spaced 22.5MHz apart from the second 5MHz DL component carrier in the DL band. Alternatively, a contiguous aggregate transmission bandwidth may be used. For example, a first component carrier of 15MHz may be aggregated with another DL component carrier of 15MHz and paired with a UL carrier of 20 MHz. Fig. 2 shows non-contiguous spectrum aggregation using component carrier 205, while fig. 3 shows contiguous spectrum aggregation using component carrier 305.

Fig. 4 illustrates reserved time-frequency locations for Physical Uplink Control Channel (PUCCH) transmissions according to LTE R8. The PUCCH is used to transmit control data on the uplink. FIG. 4 shows a sub-frame consisting of two slots 402, whereIndicates the number of Resource Blocks (RBs) available for uplink transmission and n_PRBIs indexed for RB. RBs on the edge of the spectrum may be used for PUCCH transmission and RBs on the opposite edge may be used in two slots to improve diversity. For example, the WTRU may use the RB indicated by m-1 for PUCCH transmission. The control data carried by the PUCCH may include, but is not limited to, acknowledgement/negative acknowledgement (ACK/NACK) information for DL transmissions, Scheduling Requests (SRs), Channel Quality Indicators (CQIs) to enable scheduling for DL transmissions, Rank Indicator (RI) information, and Precoding Matrix Indicator (PMI) information to enable MIMO operation. Here, the term CQI is generalized to also include PMI and RI. According to LTER8, PUCCH for CQI reporting and PUCCH for Scheduling Requests (SRs) are configured to be periodic so that each PUCCH reports information for only one downlink carrier.

The PUCCH configuration in LTE R8 is designed for one component carrier. Therefore, it is desirable to develop a new configuration of PUCCH for LTE-a using carrier aggregation, where more than one component carrier may be transmitted in DL at a time while supporting CQI (including PMI and RI) reporting for multiple downlink carriers and efficient SR reporting with little influence from Discontinuous Reception (DRX) cycles over multiple carriers. More generally, it is desirable to develop techniques for reporting multiple parallel DL carrier information simultaneously in a multi-carrier communication system.

Multicarrier systems using carrier aggregation, such as LTE-a, may include anchor and non-anchor component carriers. This may reduce overhead because system information, synchronization, and paging information for the cell may be transmitted only on the anchor carrier. The anchor carrier may initiate synchronization, occupation, and access in heterogeneous network environments, where reference coordinates may be provided for at least one detectable or accessible anchor carrier.

Multiple carriers may exist in DL and UL for carrier aggregation. However, the carrier quality may change and/or the DL or UL traffic may change in a dynamic or semi-persistent manner. Accordingly, it is desirable to provide flexible and efficient DL and UL component carrier allocation and switching (switch) to provide improved utilization and transmission quality for multi-carrier systems using carrier aggregation such as LTE-a.

Disclosure of Invention

A method and apparatus for carrier allocation, configuration, and switching for multi-carrier wireless communication is disclosed. A single Uplink (UL) primary carrier may provide control information for multiple parallel Downlink (DL) carriers. Alternatively, DL carriers may be paired with UL carriers, such that control information for each DL carrier is transmitted over the DL carrier of the DL carrier pair. Carrier switching of UL and/or DL carriers, including primary and anchor carriers, may be initiated by a wireless transmit/receive unit (WTRU) or an evolved node b (enb), and may occur only during normal operation or handover (handover). Carrier switching in either the UL or DL direction only may occur. A unidirectional handover is performed when either only UL carrier or only DL carrier is switched as part of the handover. The switching of UL and/or DL carriers may be from one component carrier to another component carrier, a subset of carriers, or all carriers in the same direction. Alternatively, the carrier switch may be from a subset of carriers to one component carrier, another subset of carriers, or all carriers in the same direction.

Drawings

The invention will be understood in more detail from the following description, given by way of example and understood in conjunction with the accompanying drawings, in which:

fig. 1 illustrates the mapping of transport blocks to LTE carriers according to LTE R8;

fig. 2 illustrates non-contiguous spectrum aggregation according to LTE-a;

fig. 3 illustrates continuous spectrum aggregation according to LTE-a;

figure 4 shows an LTE PUCCH structure;

figure 5 illustrates an example wireless communication system including a plurality of wireless transmit/receive units (WTRUs) and an evolved node-b (enb);

figure 6 shows an example functional block diagram of the WTRU and eNB of figure 5;

fig. 7 shows a UL primary carrier for DL control information;

fig. 8 shows pairing of UL and DL carriers for transmitting DL control information on the UL;

fig. 9 shows a flow diagram for transmitting control information for a set of DL component carriers using an uplink primary carrier;

fig. 10 shows a flow diagram for pairing UL and DL carriers for transmitting control information of DL component carriers on the UL;

fig. 11A, 11B, 12A and 12B show examples of carrier switching on a common eNB; and

fig. 13A, 13B, 14A, and 14B illustrate examples of carrier switching from one eNB to another eNB, where the switching is referred to as unidirectional (unidirectional) handover.

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 type of user equipment capable of operating in a wireless environment. The term "base station" as referred to below includes, but is not limited to, a node-B, a site controller, an Access Point (AP), or any other type of interfacing device capable of operating in a wireless environment.

The embodiments described below are applicable to any system using multi-carrier communication, including but not limited to Orthogonal Frequency Division Multiple Access (OFDMA) and Orthogonal Frequency Division Multiplexing (OFDM). Examples of wireless communication systems using multi-carrier communication include, but are not limited to, Long Term Evolution (LTE), LTE-advanced (LTE-a), Institute of Electrical and Electronics Engineers (IEEE)802.11, IEEE 802.16m, Worldwide Interoperability for Microwave Access (WiMAX). The following embodiments are described by way of example based on LTE and LTE-a technologies, but are not limited to these technologies and may be applied to any multi-carrier communication system. The feedback information and/or the control information is referred to herein as control information.

Fig. 5 illustrates a Long Term Evolution (LTE) wireless communication system/access network 500 that includes an evolved universal terrestrial radio access network (E-UTRAN) 505. The E-UTRAN 505 includes a number of evolved node Bs (eNBs) 520. The WTRU510 communicates with the eNB 520. Node enbs 520 are connected to each other using an X2 interface. Each eNB520 is connected with a Mobility Management Entity (MME)/serving gateway (S-GW)530 through an S1 interface. Although a single WTRU510 and three enbs 520 are shown in fig. 5, it should be understood that any combination of wireless and wired devices may be included in the wireless communication system access network 500.

Figure 6 is an example block diagram of an LTE wireless communication system 600 including a WTRU510, an eNB520 and an MME/S-GW 530. As shown in fig. 6, a WTRU510, an eNB520, and an MME/S-GW530 are configured to implement methods of carrier allocation and switching for multi-carrier wireless communications.

In addition to the elements that may be found in a typical WTRU, the WTRU510 includes a processor 616 with an optional link memory 622, at least one transceiver 614, an optional battery 620, and an antenna 618. The processor 616 is configured to implement methods for carrier allocation and switching for multi-carrier wireless communications. The transceiver 614 is in communication with the processor 616 and the antenna 618 to facilitate the transmission and reception of wireless communications. In the case where a battery 620 is used in the WTRU510, the battery 620 powers the transceiver 614 and the processor 616.

In addition to the elements that may be found in a typical eNB, the eNB520 includes a processor 617 with an optional linked memory 615, a transceiver 619, and an antenna 621. The processor 617 is configured to implement methods for carrier allocation and switching for multi-carrier wireless communication. The transceiver 619 communicates with the processor 617 and the antenna 621 to facilitate the transmission and reception of wireless communications. The eNB520 is connected to a mobility management entity/serving gateway (MME/S-GW)530, wherein the MME/S-GW530 includes a processor 633 with an optional linked memory 634.

In a first embodiment, control information for any number of DL carriers may be provided on a single UL carrier, referred to herein as a primary UL carrier. The primary carrier may be an UL anchor carrier or any other type of UL carrier. A primary carrier may be defined as a carrier allocated to carry control information for a DL carrier. Alternatively, there may be multiple primary carriers such that each DL carrier is paired with an UL carrier, so that control information for each DL carrier may be transmitted on the primary carrier to which each DL carrier corresponds.

Fig. 7 illustrates an UL primary carrier for DL control information 700 in accordance with the description herein. In fig. 7, a single UL primary carrier 704 is used to carry control information for one or more DL component carriers 702. The non-primary uplink carrier 706 may not be used to transmit control information for the downlink carrier 702. The primary UL carrier 706 may be a UL anchor carrier or any other UL carrier.

Fig. 8 illustrates UL and DL carrier pairing for transmitting control information on UL 800 according to the description herein. In fig. 8, each DL carrier 802_a，802_b，......802_nCorresponding UL carrier 806_a，806_b，......806_nPairing to be used for each DL carrier 802_a，802_b，......802_nIn the corresponding paired UL carrier 806_a，806_b，......806_nIs transmitted.

Fig. 9 illustrates a flow diagram 900 for transmitting control information for a set of DL component carriers using an uplink primary carrier in accordance with the description herein. At 905, the WTRU receives first configuration information for a set of UL carriers and a set of DL carriers. The first configuration information may be included in one or more different messages. For example, the configuration information for the set of UL carriers may be received in a separate message on configuration information from the set of DL carriers or a different subset of UL carriers. At 910, the WTRU configures a set of UL carriers and a set of DL carriers according to the first configuration information. At 915, the WTRU receives second configuration information for the UL primary carrier. The first configuration information and the second configuration information may be received in a common message or in separate messages. At 920, the WTRU configures the UL primary carrier according to the second configuration information. At 925, the WTRU receives the message over the set of DL carriers. At 930, the WTRU transmits control information for the set of DL carriers on the UL primary carrier. The WTRU may transmit control information for all carriers or a subset of carriers of the set of DL carriers over the UL primary carrier.

Fig. 10 shows a flow diagram 1000 for pairing UL and DL carriers to transmit control information for DL component carriers on the UL in accordance with the description herein. At 1005, the WTRU receives first configuration information for a set of UL carriers and a set of DL carriers. The first configuration information may be included in one or more different messages. For example, the configuration information for the set of UL carriers may be received in a separate message from the configuration message for the set of DL carriers or a different subset of UL carriers. At 1010, the WTRU configures a set of UL carriers and a set of DL carriers according to the first configuration information. At 1015, the WTRU receives second configuration information for allocating an UL carrier to carry control information for a set of DL carriers. The allocated UL carrier may or may not be an anchor carrier or a primary carrier. The first configuration information and the second configuration information may be received in a common message or in separate messages. At 1020, the WTRU allocates a corresponding UL carrier to each DL carrier that is subordinate to a set of DL carriers according to the second configuration information. At 1025, the WTRU receives a message on the DL carrier set. At 1030, the WTRU transmits control information for each DL carrier over its corresponding UL carrier. Referring to fig. 6, the receiving and transmitting of carriers may be performed by the transceiver 614 and the configuring and pairing of carriers may be performed by the processor 616.

Taking IEEE 802.16m multi-carrier operation as an example, control information for each active DL carrier needs to be reported back to the Advanced Base Station (ABS) so that efficient frequency selection and spatial scheduling can be implemented in the DL. The control information for each active DL carrier may include, but is not limited to, DL channel quality feedback, DL multiple-input multiple-output (MIMO) feedback, and DL HARQACK/NACK. For a DL carrier that uses a paired UL carrier, the feedback control information for the DL carrier may be configured to be transmitted on the UL carrier to which the DL carrier corresponds. For DL carriers that do not have a paired UL carrier, feedback control information for the DL carrier may be transmitted on an Advanced Mobile Station (AMS) UL primary carrier. The UL primary carrier N_DLIs specific to AMS.

Taking LTE-A as an example, set N_ULAnd N_DLThe number of aggregated carriers in the uplink and downlink, respectively. N is a radical of_ULMay be equal to N_DLOr may not beIs equal to N_DL(ii) a The latter case is called asymmetric carrier aggregation. Since multiple aggregated carriers are used in LTE-a, Channel State Information (CSI) or CQI, including Precoding Matrix Index (PMI) and Rank Information (RI) for each DL component carrier in the aggregated carriers, needs to be reported back to the eNB so that efficient frequency selection and spatial spectrum scheduling can be achieved in the DL. According to a first embodiment, the PUCCH for periodic reporting of CSI and/or CQI for all DL component carriers is configured to be transmitted on the primary carrier in the UL. The PUCCH used for periodic reporting of CSI and/or CQI for all downlink carriers is transmitted on the primary carrier designated for PUCCH transmission and may not be present on other non-primary UL carriers. The primary carrier allocated to transmit the PUCCH may carry any type of control information including, but not limited to, PUCCH, CQI, CSI, PMI, RI, ACK/NAK information, HARQ feedback, and Scheduling Request (SR). The UL primary carrier may be WTRU-specific, and the designation of the UL primary carrier may be signaled to the WTRU through RRC signaling, L1 signaling, or MAC Control Element (CE). Alternatively, the primary carrier may be cell-specific. An LTE-a WTRU may obtain information about a primary carrier by acquiring a Master Information Block (MIB) or a System Information Block (SIB).

Alternatively, the PUCCH for periodically reporting CSI/CQI for each downlink carrier may be configured to be transmitted on the corresponding UL carrier paired with the DL carrier. The mapping between UL and DL carriers may be WTRU-specific and signaled to the WTRU through RRC signaling, L1 signaling, or MAC Control Element (CE). Alternatively, the mapping between uplink and downlink carriers may be cell specific. An LTE-a WTRU may obtain information by acquiring an MIB or SIB. The mapping between uplink and downlink carriers may be fixed and specified in the standard.

The periodicity of CSI and/or CQI reports for different downlink carriers may be configured to be equal or different. For example, the CSI/CQI reporting period for the downlink anchor carrier may be configured to be less than the CSI/CQI reporting period for the downlink non-anchor carrier. In other words, the CSI/CQI reporting period for the downlink non-anchor carrier may be an integer multiple of the CSI/CQI reporting period for the downlink anchor carrier. In this way, the CSI/CQI for the downlink anchor carrier is configured to be reported more frequently than the downlink non-anchor carrier. The offsets in the reporting periods for CSI/CQI reporting for different downlink carriers may be configured to be equal or different, regardless of whether the CSI/CQI reporting periods for the different downlink carriers are equal.

For example, assume that PUCCH is mapped onto the primary carrier for all DL carriers as described above. If the anchor carrier has limited PUCCH resources for CSI/CQI reporting, the network may configure the offsets for different carriers to be different so that the total amount of PUCCH resources in any subframe is minimized. Regardless of the relative reporting periodicity of the DL carriers, the system frame/subframe offset may be configured such that PUCCH reporting for a particular DL carrier does not overlap reporting for other DL carriers. Alternatively, PUCCH reports may be staggered on each DL carrier. One way to accomplish this is to configure the same PUCCH periodicity for each associated DL carrier, but configure a different subframe offset for each associated DL carrier. Alternatively, the periodic PUCCH may also be configured to alternate reporting for each DL carrier. The PUCCHCSI/CQI reporting may be defined to be sequentially switched according to a predetermined list of DL carriers or may be configured to report with higher or lower periodicity for a particular carrier. For example, one DL carrier may be reported every two PUCCH frames and the other two carriers may be reported every four PUCCH frames. In another example, to maintain periodic reporting for any particular carrier, a modulo-2 multiple between reporting rates may be used to fully exploit the periodic PUCCH configuration. For any of the solutions, the presence of the PUCCH transmission may be limited by DRX or activation/deactivation status of the associated DL carrier. When the WTRU is not receiving PDCCH on a particular DL carrier, if the primary UL carrier has many PUCCH resources to support CSI/CQI reporting for multiple downlink carriers simultaneously, the network may configure the offsets of the different carriers to be the same so that the PUCCH for CSI/CQI reporting of the different carriers is adjusted. As such, the DRX cycle or activation/deactivation state has little impact on CSI/CQI reporting for multiple downlink carriers.

Although multiple aggregated carriers are used in LTE-a, only one total WTRU data transmission buffer may be maintained. Thus, based on buffer occupancy, only one Scheduling Request (SR) may be needed for the eNB so that uplink channel resources may be scheduled for the WTRU. The PUCCH for SR reporting may be configured when the following method is used. In one embodiment, PUCCH reporting of SR is configured to be periodic and transmitted on the primary carrier in the UL. PUCCH reporting for SR may not exist on non-primary UL carriers. The UL primary carrier may be WTRU-specific and signaled to the WTRU through RRC signaling, L1 signaling, or MAC Control Element (CE). WTRU-specific UL and DL primary carriers allow for improved load balancing on the UL and DL carriers. Alternatively, the primary carrier may be cell-specific. An LTE-a WTRU may obtain information about a primary carrier by acquiring a Master Information Block (MIB) or a System Information Block (SIB). In a cell-specific case, all WTRUs with the same primary DL carrier may have the same primary UL carrier. The default way of operation may use the cell-specific UL primary carrier until the WTRU-specific RRC reconfiguration procedure is applied.

In another embodiment, PUCCH reporting of SR may be configured to be periodic and transmitted in an uplink set, where the set may include more than one carrier but less than a set of all UL carriers. The periodicity and offset of the PUCCH mapped to different uplink carriers may be configured to be the same or different. The WTRU may transmit in one PUCCH or a subset of the PUCCH if the PUCCH for its SR report is configured on some uplink carriers in the same subframe, where the PUCCH may be specified by a standard.

For PUCCH for SR reporting, it is assumed that the network can determine the UL carrier allocated for the uplink shared channel (UL _ SCH). Alternatively, the WTRU may request UL SCH resources by transmitting an SR on the UL carrier for which UL resources are requested. As such, the WTRU may dynamically request UL _ SCH allocation on a particular UL carrier. The decision criteria for generating an SR on a particular UL carrier may be based on traffic capacity and/or relative to allocation capabilities on other UL carriers, thereby supporting current UL transmission requirements.

For IEEE 802.16m, carriers may be allocated to use multi-carrier operation to carry Physical (PHY) and/or Medium Access (MAC) control signaling in addition to data traffic for each advanced mobile station, referred to as primary carriers. In TDD mode, one carrier may be used as a primary carrier for both DL and UL. In the FDD mode, DL and UL carriers may be used as a DL primary carrier and an UL primary carrier, respectively. The primary carrier of the AMS may be dynamically changed according to the description herein. Furthermore, the dynamic change methods disclosed herein may be applied to any one UL or DL carrier, and any new set of UL and/or DL carriers may be allocated in a dynamic or semi-persistent manner. The dynamic change methods disclosed herein may be applied to both UL and DL carriers together or separately in either UL or DL carrier during a unidirectional handover procedure.

For each primary carrier or anchor carrier approach described herein, the UL primary carrier, anchor carrier, or any other carrier may be switched over within the configured set of UL carriers. The transition may be initiated by the WTRU or eNB and signaled according to RRC, MAC, or physical control signaling methods. In this case, the handover may be part of an intra-cell handover procedure. Additionally, the UL primary carrier, anchor carrier, or any other carrier may be switched to an UL carrier, wherein the UL carrier is not part of a currently configured set of UL carriers within a current cell. In this case, the transition may be part of an inter-cell handover procedure. The procedure may be initiated by the eNB or WTRU.

For LTE-a, the UL carrier, which is referred to as the primary carrier or UL anchor carrier, may be allocated as a PUCCH, similar to the DL anchor carrier that carries the Physical Downlink Control Channel (PDCCH). The primary carrier may be an UL anchor carrier or any other UL carrier. The DL anchor carrier, as well as the UL primary carrier including the UL anchor carrier, may also be used to carry HARQ feedback, SR and CQI/CSI, as well as other information. Other non-primary UL carriers may not be used to carry HARQ feedback, SR and CQI/CSI, as well as other information. As described herein, a DL anchor carrier and an UL primary carrier including a UL anchor carrier may be dynamically switched. Furthermore, the dynamic switching methods disclosed herein may be applied to any UL or DL carrier, and any new set of UL and/or DL carriers may be allocated in a dynamic or semi-persistent manner. The dynamic switching methods disclosed herein may be applied to both UL and DL carriers together or separately in either UL or DL carrier during a unidirectional handover or carrier reconfiguration procedure.

During normal operation, where the WTRU does not need to switch, or during a handover, the WTRU may switch DL and/or UL carriers including an anchor carrier or a primary carrier. The handover may be inter-cell or intra-cell and may be controlled by the eNB or the WTRU may initiate a forward handover. The switching of the DL and/or UL carriers may be dynamic, which may be considered fast, or semi-persistent, which may be considered slow. The DL and/or UL component carriers that are switched at the WTRU may be triggered by signaling from the eNB or based on a pre-configured switching or frequency hopping pattern. The triggering of the DL anchor carrier switch may be eNB or WTRU initiated. The reallocation of the DL primary carrier or anchor carrier may be a carrier within the current set of DL carriers being received by the WTRU or a new DL carrier that is not part of the active set of DL carriers currently being used for the WTRU. The WTRU reconfiguration procedure may be optimized when a new primary or anchor carrier is assigned within the current active DL carrier set, so that no reset and re-determination of RLC and PDCP protocols is required.

Methods for dynamic and semi-persistent transitions and unidirectional handovers are specifically discussed below and may be applied to any kind of carrier, including primary carriers, anchor carriers, non-anchor carriers, or any active carrier in both UL and DL directions. The methods described in relation to the anchor carrier may be applied interchangeably to the primary carrier or the non-anchor carrier and vice versa.

The switching of DL and/or UL component carriers may follow a number of possible schemes. According to one scheme, the transition is from one component carrier to another component carrier. According to another aspect, the transition may be from one component carrier to another subset of carriers, where the other subset of carriers may or may not include a trigger carrier, which may be an anchor carrier or a primary carrier. Alternatively, the switching may be from one component carrier to all component carriers. In another aspect, the switching may be from one subset or all of the component carriers to one component carrier, which may be an anchor carrier or a primary carrier. According to another aspect, the switching may be from a subset of component carriers to another subset of component carriers or all component carriers in the DL or UL direction. In another aspect, the switching may be from all component carriers in the DL or UL direction to a subset of component carriers.

Switching the carrier set by increasing the number of carriers is called spreading. Similarly, switching a carrier set by reducing the number of carriers is referred to as compression. DL and/or UL component carrier switching or extension may be signaled using RRC and/or L1/L2 signaling; for example, PDCCH, PUCCH or Medium Access Control (MAC) layer may be used. RRC messages may be used to signal the transition signal, or MAC Control Elements (CEs) and PDCCH may be used to carry the transition signaling to the WTRU. RRC messages may be used to provide component carrier configuration and PDCCH or MAC CE may be used to signal the transition. The ability to use PDCCH/PUCCH and/or MAC CE signaling may also be used only for intra-cell carrier switching. Switching the UL or DL anchor carrier or primary carrier may be performed in a current set of active carriers. RRC messages may also be used to signal a transition or frequency hopping pattern for the WTRU to follow and conduct inter-cell handovers. Frequency hopping and DL signaling may be used to trigger component carrier switching, where a signal is transmitted from the eNB to the WTRU through the PDCCH or MAC CE from the time the WTRU uses the frequency hopping method. Frequency hopping and DL signaling may be initiated when the WTRU switches component carriers according to DL signaling. The WTRU may send an acknowledgement for the carrier switch message to maintain alignment (alignment) of the active carrier between the WTRU and the eNB when the PDCCH or MAC CE is used to signal a carrier switch signal. Furthermore, with respect to PDCCH or MAC CE reception, transition of time synchronization on subframe boundaries may be defined.

According to one embodiment, the switching of DL and/or UL component carriers may be from one component carrier to another component carrier. When a WTRU switches from one anchor carrier to another, the switch may occur. The RRC message included in the handover command may be used to signal an anchor carrier switch from one cell to another if the switch occurs during handover. The message contained within the PDCCH or MAC CE or handover command may include any or all of the following information: a starting Transmission Time Interval (TTI), such as a System Frame Number (SFN), used by the WTRU to monitor for acquisition of a new DL anchor carrier or to transmit on a new UL carrier; a TTI (e.g., SFN) to be used by the WTRU to disconnect an existing UL/DL anchor carrier; the WTRU may stay on a new DL/UL anchor carrier and how long the WTRU will monitor a subsequent anchor carrier; and a trigger to start an inactivity timer or an on-duration timer for Discontinuous Reception (DRX) on the new anchor carrier. When switching anchor carriers, configurations for different carriers may be maintained. Alternatively, the configuration for some carriers may be changed.

In addition to using PDCCH or MAC CE to trigger a transition from an existing anchor carrier to another anchor carrier, the transition may also track a frequency hopping pattern, which may be signaled through RRC messages. The eNB may use the PDCCH or MAC CE to signal the WTRU to terminate the carrier hopping pattern and ask the WTRU to follow the information contained on the PDCCH or MAC CE to trigger a carrier switch. Alternatively, the eNB may use PDCCH or MAC CE to activate carrier switching while following the frequency hopping pattern signaled by RRC.

According to another embodiment, the switching of DL and/or UL component carriers may be from one component carrier to another set of carriers, wherein the other set of carriers may not include a trigger carrier and may be only an anchor carrier, which may be a primary carrier or all component carriers. The transition may occur when there is DL data requiring more DL component carriers to be activated by the anchor carrier, where the anchor carrier previously declared may be the primary carrier. The activation of other DL component carriers may be performed through PDCCH or MAC CE. The PDCCH or MAC CE may also include an indicator of which DL component carriers may be activated. The parameters of the carriers to be activated may be the same or different for each carrier. For example, the inactivity timer for each component carrier may be different. A subset of carriers may be activated simultaneously, but depending on the DL transmission activity, some component carriers may be deactivated (deactivated) by the anchor carrier through the PDCCH or MAC CE. Each component carrier in the subset of component carriers will automatically go to sleep (sleep) if the DL transmission on that carrier completes successfully. If the transition occurs during handover, an activation message may be included in the handover command.

According to another embodiment, the switching of the DL and/or UL component carriers may be from one subset of component carriers or all component carriers to one component carrier, such as an anchor carrier, wherein the anchor carrier may be a primary carrier. The transition may occur when some or all of the component carriers are activated from a dormant state for data transmission, then complete transmission and return to sleep mode. In addition to the anchor (primary) carrier, for each component carrier in the subset of component carriers, the transition deactivating the carrier may be signaled through the PDCCH or MAC CE. Alternatively, carriers other than the anchor carrier may be deactivated automatically based on expiration of one or more timers. Alternatively, the message may be contained only in PDCCH or MAC CE on the anchor carrier. During the transition, the reserved anchor carriers may be different from the anchor carriers of the active component carrier subset. The activation message may be included in a handover command if a transition occurs during handover.

According to another embodiment, the switching of DL and/or UL component carriers may be from a subset of component carriers to another subset of component carriers or into all component carriers. Similarly, the transition may be from all component carriers to a subset of component carriers. The transition may be signaled to the WTRU through PDCCH or MAC CE on the anchor carrier. Alternatively, messages from all active component carriers may be included in the PDCCH or MAC CE. Upon receipt of the message, the WTRU may deactivate some component carriers and activate other carriers depending on the signal being sent. The activation message may be included in the handover command if a transition occurs during handover. The transition may also occur based on a pre-configured frequency hopping pattern signaled through RRC messages.

The switching of anchor carriers and active carrier sets may be applied in inter-cell handovers. Any one of the active UL or DL carriers may be reallocated as an anchor carrier through PDCCH/PUCCH or MAC signaling without RRC reconfiguration. Explicit signaling acknowledgements may be sent via HARQ acknowledgement signals, although implicit acknowledgements are also possible, such as by detecting PDCCH or PUCCH reallocation for a WTRU on a particular carrier. The existing configuration may be conveyed into the new anchor carrier. The configuration may be outside of the PDCCH and PUCCH configurations and include configurations such as DRX cycle and associated timers, semi-persistent scheduling configuration, HARQ entity/process allocation, and others.

For intra-cell handovers, the switching of the anchor carrier or primary carrier or active carrier set may be applied only to UL-only carriers or only DL carriers. The transition may be considered a unidirectional handover. Only the configuration and operation in the direction is affected by the carrier switching. The carrier switching criteria may be, for example, carrier quality measurements or traffic congestion. The WTRU may use a Radio Link Failure (RLF) procedure, or the eNB may use sounding (sounding) reference signal (SRS) or channel quality measurement (CQI) reception to cause the procedure. The WTRU may detect RLF on one or more DL component carriers and choose to cause a DL carrier switching procedure. The DL switching procedure may be uniquely applied to a DL anchor carrier or a primary carrier. The WTRU-initiated procedure may be done by RRC, MAC CE, or PUCCH signaling. The eNB may detect criteria for UL component carrier switching from SRS reception on each configured UL carrier. The eNB-initiated UL or DL Component Carrier (CC) switching procedure may be accomplished through RRC, MAC CE, or PDCCH signaling.

Fig. 11A, 11B, 12A, and 12B show examples of carrier switching on a common eNB. In fig. 11A and 11B, DL carrier 1110_A、1110_BAnd 1110_CAnd UL carrier 1112_A、1112_BAnd 1112_CMay be configured between the eNB 1102 and the WTRU 1106. DL carrier 1110_A、1110_BAnd 1110_CAnd UL carrier 1112_A、1112_BAnd 1112_CMay include an anchor carrier, a primary carrier, and a non-anchor carrier. In fig. 11A and 11B, the transmission is present on carrier 1110_A、1110_B、1110_C、1112_A、1112_BAnd 1112_COn any of the carriers 1110, wherein the carrier is a carrier_A、1110_B、1110_C、1112_A、1112_BAnd 1112_CMay be currently configured, active, and have a valid DL scheduling assignment or UL grant. In fig. 11A, a DL primary carrier or anchor carrier is configured at a DL carrier 1110_AAnd either the UL primary carrier or the anchor carrier is configured on UL carrier 1112_BAnd, as shown in phantom. In fig. 11B, there was previously a UL carrier 1112_BThe UL primary carrier on is switched to the allocatedUL carrier 1112 within a localized carrier set_CThe above. For example, UL primary or anchor carrier 1112_BMay be switched to a new UL primary or anchor carrier 1112_CThe above. Switching in UL and DL may occur separately or unidirectionally so that when an UL carrier is switched, a DL carrier may not be switched.

Similarly, in fig. 12A and 12B, DL carrier 1210_A、1210_BAnd 1210_CAnd UL carrier 1212_A、1212_BAnd 1212_CIs configured between the eNB 1202 and the WTRU 1206. DL carrier 1210_A、1210_BAnd 1210_CAnd UL carrier 1212_A、1212_BAnd 1212_CMay include an anchor carrier, a primary carrier, and a non-anchor carrier. In fig. 12A and 12B, the transmission is present on carrier 1210_A、1210_B、1210_C、1212_A、1212_BAnd 1212_COn any of the carriers 1210, wherein the carrier_A、1210_B、1210_C、1212_A、1212_BAnd 1212_CMay be currently configured, active, and have a valid DL scheduling assignment or UL grant. In fig. 12A, a DL primary carrier or anchor carrier is configured on a DL carrier 1210_AAnd either the UL primary carrier or the anchor carrier is configured on UL carrier 1212_BAnd, as shown in phantom. In fig. 12B, there was previously a DL carrier 1210_AThe primary carrier on DL is switched to DL carrier 1210 in the configured carrier set_CThe above. For example, a DL primary carrier or anchor carrier 1210_AMay be switched to a new DL primary carrier or anchor carrier 1210_CThe above. Switching in UL and DL may occur separately or unidirectionally so that when a DL carrier is switched, an UL carrier may not be switched.

Fig. 11A, 11B, 12A, and 12B depict carrier switching examples on a common eNB within an existing configured carrier set. In these examples, the primary carrier or anchor carrier is switched within the currently configured set of carriers. In a similar manner, carriers may be switched outside of the previously configured set of carriers by configuring a new carrier and then performing the switching. Further, the configured set of carriers may be expanded or compressed during carrier switching. A similar procedure may be applied to non-primary carriers or non-anchor carriers.

Fig. 13A, 13B, 14A and 14B show examples of carrier switching from one eNB to another eNB, which is referred to as unidirectional handover. In fig. 13A and 13B, a DL carrier 1310_A、1310_BAnd 1310_CAnd UL carrier 1312_A、1312_BAnd 1312_CIs configured between the eNB 1302 and the WTRU 1306. Also, DL carrier 1310_DIs configured between the eNB1304 and the WTRU 1306. DL carrier 1310_A、1310_BAnd 1310_C、1310_DAnd UL carrier 1312_A、1312_BAnd 1312_CMay include an anchor carrier, a primary carrier, and a non-anchor carrier. In fig. 13A and 13B, the transmission is present on a carrier 1310_A、1310_B、1310_C、1310_D、1312_A、1312_BAnd 1312_COn any of the carriers 1310, wherein the carrier 1310 is_A、1310_B、1310_C、1310_D、1312_A、1312_BAnd 1312_CMay be currently configured, active, and have a valid DL scheduling assignment or UL grant. In fig. 13A, a DL primary carrier or anchor carrier is configured on a DL carrier 1310_AAnd either the UL primary carrier or the anchor carrier is configured on UL carrier 1312_CAnd, as shown in phantom. In fig. 13B, there was previously a DL carrier 1310_AThe DL primary carrier on is converted to a DL carrier 1310 configured on the eNB1304_DAs part of a unidirectional handover. For example, a DL primary or anchor carrier 1310_ANew DL primary or anchor carrier 1310 that may be switched to on the new eNB1304_DThe above. Switching in UL and DL may occur separately or unidirectionally so that when an UL carrier is switched, a DL carrier may not be switched.

In FIG. 14A and FIG. 14BIn 14B, DL carrier 1410_A、1410_BAnd 1410_CAnd UL carrier 1412_A、1412_BAnd 1412_CMay be configured between the eNB 1402 and the WTRU 1406. Also, UL carrier 1412_DIs configured between the eNB1404 and the WTRU 1406. DL carrier 1410_A、1410_BAnd 1410_C、1410_DAnd UL carrier 1412_A、1412_BAnd 1412_CMay include an anchor carrier, a primary carrier, and a non-anchor carrier. In fig. 14A and 14B, the transmission is present on carrier 1410_A、1410_B、1410_C、1412_A、1412_B、1412_CAnd 1412_DOn any of the carriers 1410, wherein the carrier is a carrier_A、1410_B、1410_C、1412_A、1412_B、1412_CAnd 1412_DMay be currently configured, active, and have a valid DL scheduling assignment or UL grant. In fig. 14A, a DL primary carrier or anchor carrier is configured at a DL carrier 1410_AAnd a UL primary carrier or anchor carrier is configured on UL carrier 1412_CAnd, as shown in phantom. In fig. 14B, there was previously a presence of UL carrier 1412_CThe UL primary carrier on is switched to a UL carrier 1412 configured on the eNB1404_DAs part of a unidirectional handover. For example, UL primary carrier or anchor carrier 1412_CCan be switched to a new UL primary carrier or anchor carrier 1412 on the new eNB1404_DThe above. Switching in UL and DL may occur separately or unidirectionally so that when an UL carrier is switched, a DL carrier may not be switched.

Fig. 13A, 13B, 14A and 14B illustrate examples of carrier switching (such as unidirectional handover) between different enbs within an existing configured carrier set. In the example, the primary carrier or anchor carrier is switched within the currently configured set of carriers. In a similar manner, carriers may be switched outside of the previously configured set of carriers by configuring a new carrier on the target eNB and then performing the switch. Further, the configured set of carriers may be expanded or compressed during carrier switching on an existing eNB or a target eNB. It should also be noted that a similar procedure may be applied to non-primary carriers or non-anchor carriers.

Examples

1. A method for multi-carrier wireless communication.

2. The method of embodiment 1, further comprising:

first configuration information for a set of Downlink (DL) carriers and a set of Uplink (UL) carriers is received.

3. The method of any preceding embodiment, further comprising:

configuring the DL carrier set and the UL carrier set according to the first configuration information.

4. The method of any preceding embodiment, further comprising:

second configuration information for allocating the UL primary carrier is received.

5. The method of any preceding embodiment, further comprising:

allocating the UL primary carrier according to the second configuration information.

6. The method of any preceding embodiment, further comprising:

a message is received over the configured set of DL carriers.

7. The method of any preceding embodiment, further comprising:

transmitting control information for the configured set of DL carriers over the UL primary carrier.

8. The method of any preceding embodiment, wherein the first configuration information and the second configuration information are received in a common message.

9. The method of any preceding embodiment, further comprising:

pairing each DL carrier from the set of configured DL carriers with a corresponding UL carrier from the set of configured UL carriers.

10. The method of embodiment 9, further comprising:

transmitting control information for each DL carrier from the configured set of DL carriers over the corresponding UL carrier.

11. The method of any preceding embodiment wherein the DL carrier set and the UL carrier set are component carriers in long term evolution advanced (LTE-a) wireless communications.

12. The method of any preceding embodiment, wherein the UL primary carrier is an anchor carrier.

13. The method of any preceding embodiment, wherein the control information comprises at least one of:

physical UL Control Channel (PUCCH), hybrid automatic repeat request (HARQ) feedback, Scheduling Request (SR), Channel State Information (CSI), Channel Quality Information (CQI), Precoding Matrix Index (PMI), or Rank Information (RI).

14. The method of any of embodiments 1-10 wherein the DL carrier set and the UL carrier set are carriers in Institute of Electrical and Electronics Engineers (IEEE)802.16m wireless communications.

15. The method of any preceding embodiment, further comprising:

transmitting the UL communication over at least one UL carrier from the configured set of UL carriers.

16. The method of any preceding embodiment, further comprising:

receiving the DL communication over at least one DL carrier from the configured set of DL carriers.

17. The method of any preceding embodiment, further comprising:

receiving an instruction to switch the UL communication to a new UL carrier.

18. The method of embodiment 17, further comprising:

switching the UL communication from at least one UL carrier to a new UL carrier according to the instruction.

19. The method of any preceding embodiment, further comprising:

continuing to receive the DL communication over the at least one DL carrier.

20. The method as in any one of embodiments 17-19 wherein the at least one UL carrier and the new UL carrier are on a common evolved node b (enb).

21. The method as in any one of embodiments 17-19 wherein the at least one UL carrier is on a first eNB and the new UL carrier is on a second eNB, wherein switching the UL communication is part of a unidirectional handover.

22. The method as in any one of embodiments 17-21 wherein the new UL carrier is from a configured set of UL carriers.

23. The method as in any one of embodiments 17-21 wherein the new UL carrier is a non-configured carrier, the method further comprising configuring the new UL carrier prior to switching the UL communication.

24. The method of any preceding embodiment, further comprising:

receiving an instruction to switch the DL communication to a new DL carrier.

25. The method of embodiment 24, further comprising:

switching the DL communication from at least one DL carrier to the new DL carrier in accordance with the instructions.

26. The method of any preceding embodiment, further comprising:

continuing to receive the UL communication over the at least one UL carrier.

27. The method as in any one of embodiments 24-26 wherein the at least one DL carrier and the new DL carrier are on a common evolved node b (enb).

28. The method as in any one of embodiments 24-26 wherein the at least one DL carrier is on a first eNB and the new DL carrier is on a second eNB, wherein switching the DL communication is part of a unidirectional handover.

29. The method as in any one of embodiments 24-28 wherein the new DL carrier is from a configured set of DL carriers.

30. The method as in any one of embodiments 24-28 wherein the new DL carrier is a non-configured carrier, the method further comprising configuring the new DL carrier prior to switching the DL communication.

31. The method of any of the preceding embodiments, implemented by a wireless transmit/receive unit (WTRU).

32. The method as in any one of embodiments 1-30 implemented by an evolved node B (eNB).

Although the features and elements of the present invention are described above in 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 of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium, examples of which 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 execution by a general purpose computer or a processor.

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 other type of 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 videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, 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 of a Wireless Local Area Network (WLAN) module or a wireless Ultra Wide Band (UWB) module.

Claims (34)

1. A method for multi-carrier wireless communication, the method comprising:

receiving first configuration information for a Downlink (DL) carrier set and an Uplink (UL) carrier set;

configuring the DL carrier set and the UL carrier set according to the first configuration information;

receiving second configuration information for allocating an UL primary carrier;

allocating the UL primary carrier according to the second configuration information;

receiving a message over the configured set of DL carriers; and

transmitting control information for the configured set of DL carriers over the UL primary carrier.

2. The method of claim 1, wherein the first configuration information and the second configuration information are received in a common message.

3. The method of claim 1, further comprising:

pairing each DL carrier from the configured set of DL carriers with a corresponding UL carrier from the configured set of UL carriers; and

transmitting control information for each DL carrier from the configured set of DL carriers over the corresponding UL carrier.

4. The method of claim 1, wherein the set of DL carriers and the set of UL carriers are component carriers in long term evolution advanced (LTE-a) wireless communications.

5. The method of claim 4, wherein the UL primary carrier is an anchor carrier.

6. The method of claim 4, wherein the control information comprises at least one of:

physical UL Control Channel (PUCCH), hybrid automatic repeat request (HARQ) feedback, Scheduling Request (SR), Channel State Information (CSI), Channel Quality Information (CQI), Precoding Matrix Index (PMI), or Rank Information (RI).

7. The method of claim 1, wherein the DL carrier set and the UL carrier set are carriers in Institute of Electrical and Electronics Engineers (IEEE)802.16m wireless communications.

8. A method for multi-carrier wireless communication, the method comprising:

receiving configuration information for a Downlink (DL) carrier set and an Uplink (UL) carrier set;

configuring the DL carrier set and the UL carrier set according to the configuration information;

transmitting UL communications over at least one UL carrier from the configured set of UL carriers;

receiving a DL communication over at least one DL carrier from the configured set of DL carriers;

receiving an instruction to switch the UL communication to a new UL carrier;

switching the UL communication from the at least one UL carrier to the new UL carrier in accordance with the instruction; and

continuing to receive the DL communication over the at least one DL carrier.

9. The method of claim 8, wherein the at least one UL carrier and the new UL carrier are on a common evolved node b (enb).

10. The method of claim 8, wherein the at least one UL carrier is on a first eNB and the new UL carrier is on a second eNB, wherein switching the UL communication is part of a unidirectional handover.

11. The method of claim 8, wherein the new UL carrier is from a set of configured UL carriers.

12. The method of claim 8, wherein the new UL carrier is a non-configured carrier, the method further comprising configuring the new UL carrier prior to switching the UL communication.

13. A method for multi-carrier wireless communication, the method comprising:

receiving configuration information for a Downlink (DL) carrier set and an Uplink (UL) carrier set;

configuring the DL carrier set and the UL carrier set according to the configuration information;

transmitting UL communications over at least one UL carrier from the configured set of UL carriers;

receiving a DL communication over at least one DL carrier from the configured set of DL carriers;

receiving an instruction to switch the DL communication to a new DL carrier;

switching the DL communication from the at least one DL carrier to the new DL carrier in accordance with the instructions; and

continuing to receive the UL communication over the at least one UL carrier.

14. The method of claim 13, wherein the at least one DL carrier and the new DL carrier are on a common evolved node b (enb).

15. The method of claim 13, wherein the at least one DL carrier is on a first eNB and the new DL carrier is on a second eNB, wherein switching the DL communication is part of a unidirectional handover.

16. The method of claim 13, wherein the new DL carrier is from a set of configured DL carriers.

17. The method of claim 13, wherein the new DL carrier is a non-configured carrier, the method further comprising configuring the new DL carrier prior to switching the DL communication.

18. A wireless transmit/receive unit (WTRU) configured for multi-carrier wireless communication, the WTRU comprising:

a receiver configured to receive first configuration information for a Downlink (DL) carrier set and an Uplink (UL) carrier set;

a processor configured to configure the DL carrier set and the UL carrier set according to the first configuration information;

the receiver is configured to receive second configuration information for allocating an UL primary carrier;

the processor is configured to allocate the UL primary carrier according to the second configuration information;

the receiver is configured to receive a message over the configured set of DL carriers; and

a transmitter configured to transmit control information for the configured set of DL carriers over the UL primary carrier.

19. The WTRU of claim 18, wherein the first configuration information and the second configuration information are received in a common message.

20. The WTRU of claim 18, wherein:

the processor is configured to pair each DL carrier from the set of configured DL carriers with a corresponding UL carrier from the set of configured UL carriers; and

the transmitter is configured to transmit control information for each DL carrier from the configured set of DL carriers over the corresponding UL carrier.

21. The WTRU of claim 18 wherein the set of DL carriers and the set of UL carriers are component carriers in long term evolution advanced (LTE-a) wireless communications.

22. The WTRU of claim 21 wherein the UL primary carrier is an anchor carrier.

23. The WTRU of claim 21, wherein the control information comprises at least one of:

physical UL Control Channel (PUCCH), hybrid automatic repeat request (HARQ) feedback, Scheduling Request (SR), Channel State Information (CSI), Channel Quality Information (CQI), Precoding Matrix Index (PMI), or Rank Information (RI).

24. The WTRU of claim 18 wherein the set of DL carriers and the set of UL carriers are carriers in Institute of Electrical and Electronics Engineers (IEEE)802.16m wireless communications.

25. A WTRU for multi-carrier wireless communication, the WTRU comprising:

a receiver configured to receive configuration information for a set of Downlink (DL) carriers and a set of Uplink (UL) carriers;

a processor configured to configure the DL carrier set and the UL carrier set according to the configuration information;

a transmitter configured to transmit UL communications over at least one UL carrier from the configured set of UL carriers;

the receiver is configured to receive DL communications over at least one DL carrier from the configured set of DL carriers;

the receiver is configured to receive an instruction to switch the UL communication to a new UL carrier;

the WTRU configured to switch the UL communication from at least one UL carrier to a new UL carrier according to the instruction; and is

The receiver is configured to continue receiving the DL communication over the at least one DL carrier.

26. The WTRU of claim 25 wherein the at least one UL carrier and the new UL carrier are on a common evolved node b (enb).

27. The WTRU of claim 25 wherein the at least one UL carrier is on a first eNB and the new UL carrier is on a second eNB, wherein the WTRU is configured to switch the UL communication, wherein switching the UL communication is part of a unidirectional handover.

28. The WTRU of claim 25 wherein the new UL carrier is from the configured set of UL carriers.

29. The WTRU of claim 25 wherein the new UL carrier is a non-configured carrier, wherein the processor is configured to configure the new UL carrier prior to switching the UL communication.

30. A WTRU for multi-carrier wireless communication, the WTRU comprising:

a receiver configured to receive configuration information for a set of Downlink (DL) carriers and a set of Uplink (UL) carriers;

a processor configured to configure the DL carrier set and the UL carrier set according to the configuration information;

a transmitter configured to transmit UL communications over at least one UL carrier from the configured set of UL carriers;

the receiver is configured to receive DL communications over at least one DL carrier from the configured set of DL carriers;

the receiver is configured to receive an instruction to switch the DL communication to a new DL carrier;

the WTRU configured to switch the DL communication from the at least one DL carrier to the new DL carrier according to the instruction; and is

The receiver is configured to continue receiving the UL communication over the at least one UL carrier.

31. The WTRU of claim 30 wherein the at least one DL carrier and the new DL carrier are on a common evolved node b (enb).

32. The WTRU of claim 30 wherein at least one DL carrier is on a first eNB and the new DL carrier is on a second eNB, wherein the WTRU is configured to switch the DL communication, wherein switching the DL communication is part of a unidirectional handover.

33. The WTRU of claim 30 wherein the new DL carrier is from a configured set of DL carriers.

34. The WTRU of claim 30 wherein the new DL carrier is a non-configured carrier, wherein the processor is configured to configure the new DL carrier prior to switching the DL communication.