HK1165167A - Control channel feedback for multiple downlink carrier operations - Google Patents

Description

Control channel feedback for multiple downlink carrier operation

Cross Reference to Related Applications

The present application claims benefit of united states provisional applications having application number 61/256,173 filed on date 10 and 29 of 2009, application number 61/141,605 filed on date 12 and 30 of 2008, and application number 61/148,804 filed on date 1 and 30 of 2009, which are incorporated herein by reference as if fully set forth herein.

Technical Field

The present application relates to wireless communications.

Background

Personal communication devices with advanced data capabilities and data cards allow mobile computers to connect wirelessly to the internet. These devices have created an increasing demand for higher data rates and bandwidth by wireless service providers and operators. To meet these needs, wireless communication systems may use multiple carriers to transmit data. A wireless communication system using multiple carriers for transmitting data may be referred to as a multi-carrier system. Multi-carriers are gaining more widespread use in cellular and non-cellular wireless systems.

A multi-carrier system may increase the available bandwidth in a wireless communication system based on the number of available carriers. For example, a dual carrier system may have twice the bandwidth of a single carrier system, while a triple carrier system may have three times the bandwidth of a single carrier system. In addition to this throughput gain, it is also desirable to obtain diversity and joint scheduling gains. This may allow for an improved quality of service (QoS) for the end user. Furthermore, the use of multiple carriers may be combined with Multiple Input Multiple Output (MIMO).

Wireless technology continues to evolve in response to this demand for bandwidth growth. For example, the simultaneous use of two High Speed Downlink Packet Access (HSDPA) downlink carriers has been introduced as part of the third generation partnership project (3GPP) specifications. In this setup (setup), a base station (which may also be referred to as a node-B, access point, site controller, etc. in other variations or other types of communication networks) communicates with a wireless transmit/receive unit (WTRU) simultaneously over two downlink carriers. This not only doubles the available bandwidth and peak data rate of the WTRU, but also may increase network efficiency with fast scheduling and fast channel feedback on both carriers. Since this dual carrier HSDPA (DC-HSDPA) does not support MIMO, it provides only limited HSDPA functionality to date.

As data usage continues to increase rapidly, communication systems may use more than two downlink carriers. Multi-carrier operation is proposed to allow multi-carrier aggregation. Multi-carrier operation may allow the WTRU and the network to receive/transmit on two or more carriers.

While a hybrid automatic repeat request (HARQ) acknowledgement codebook has been specified for dual carriers, codebooks and associated feedback mechanisms for more than two carriers are desired.

Disclosure of Invention

Methods and apparatus for fast control channel feedback for multiple downlink carrier operation are disclosed. The WTRU receives signals on a plurality of downlink carriers, generates feedback for each of the plurality of downlink carriers based on the received signals, and transmits feedback for at least one of the plurality of downlink carriers on a first physical channel and another one of the plurality of downlink carriers on a second physical channel via a plurality of antennas.

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 shows a composite CQI report;

fig. 2 shows an HS-DPCCH frame structure;

fig. 3 illustrates an example wireless communication system in which a single carrier is used to handle uplink transmissions and multiple carriers are used to handle downlink transmissions;

fig. 4 illustrates an example wireless communication system in which multiple carriers are used for uplink transmissions and multiple carriers are used for downlink transmissions;

figure 5 is a functional block diagram of a WTRU and a node-B of the wireless communication system of figure 4;

fig. 6 illustrates an example format and channel coding for providing feedback information for additional carriers using at least one new physical control channel;

fig. 7 shows an example HS-DPCCH frame format, where two HARQ-ACK fields (HARQ1 and HARQ2) are time multiplexed;

FIG. 8 shows an example slot structure for two consecutive subframes of HS-DPCCH;

figure 9 shows another example of a possible HS-DPCCH frame structure with a spreading factor 128;

fig. 10 shows an example embodiment in which a composite CQI feedback report is derived from four separate CQI reports represented by CQI1, CQI2, CQI3, and CQI 4;

FIG. 11 shows a slot structure of two consecutive subframes of HS-DPCCH;

fig. 12 shows an example embodiment of a composite CQI report with three reports, where the three CQI reports are concatenated together;

fig. 13 shows an example embodiment in which HS-DPCCH1 may be transmitted on a serving/primary UL carrier and HS-DPCCH2 may be transmitted on a secondary carrier; and

fig. 14 shows an example of a state reduction function.

Detailed Description

The term "wireless transmit/receive unit (WTRU)" as referred to below 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 network may assign at least one Downlink (DL) carrier and/or at least one Uplink (UL) carrier as an anchor downlink carrier and an anchor uplink carrier, respectively. In multi-carrier operation, a WTRU may be configured to operate with two or more carriers (or may also be referred to as frequencies). 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 anchor or primary carriers and secondary or secondary carriers. Hereinafter, the terms "anchor carrier" and "primary carrier", and "secondary carrier", respectively, will be used interchangeably. The "anchor carrier" may also be referred to as a "primary uplink frequency" in the uplink and a "primary downlink frequency" in the downlink. Similarly, a "secondary carrier" may also be referred to as a "secondary uplink frequency" in the uplink and a "secondary downlink frequency" in the downlink. If more than two carriers are configured, the WTRU may include more than one primary carrier and/or more than one secondary carrier. The embodiments described herein are also applicable and can be extended to these cases as well. For example, an anchor carrier may be defined as a carrier used to carry a particular set of control information for downlink/uplink transmissions. Any carrier not assigned as an anchor carrier may be a secondary carrier. Alternatively, the network may not assign an anchor carrier, and a priority, preference, or default state may not be given to any downlink or uplink carrier. For multi-carrier operation, there may be more than one secondary or auxiliary carrier.

In case of performing MIMO configuration on a single MIMO carrier, DL feedback for at most two carriers or at most two streams may be implemented. Examples of the DL feedback include a high-speed dedicated physical control channel (HS-DPCCH) used to transmit ACK/NACK information and a Channel Quality Indicator (CQI) for each carrier. The ACK/NACK information is jointly encoded and transmitted on one HS-DPCCH.

Table 1 shows example channel coding for HARQ-ACK in case dual carriers are configured. The composite HARQ response message to be transmitted may be encoded into 10 bits as shown in table 1. Marking the output as w₀、w₁、...、w₉。

TABLE 1

Table 1 shows a composite CQI report. The composite CQI report is constructed from two separate CQI reports, represented by CQI1 and CQI 2. The CQI1 corresponds to a CQI associated with a serving high speed downlink shared channel (HS-DSCH) cell, and the CQI2 corresponds to a CQI associated with a secondary serving HS-DSCH cell. Two separate CQI reports are concatenated according to the following relation to form a composite channel quality indication:

(a₀ a₁ a₂ a₃ a₄ a₅ a₆ a₇ a₈ a₉)＝(cqi1₀ cqi1₁ cqi1₂ cqi1₃ cqi1₄ cqi2₀ cqi2₁ cqi2₂cqi2₃ cqi2₄)

in addition to multicarrier communication, MIMO is a technique for improving wireless capacity and range by using spatial multiplexing. MIMO uses multiple antennas to transmit information. In addition to the two ACK/NACKs for the possible two data streams and the combined CQI, a WTRU operating in MIMO mode needs to transmit Precoding Control Information (PCI).

Fig. 2 shows an HS-DPCCH frame structure. The HS-DPCCH may carry uplink feedback information related to downlink HS-DPCCH transmission. The feedback information is carried on the uplink HS-DPCCH. As shown in fig. 2, the feedback information may include a HARQ-ACK field and a CQI. For example, each 2ms subframe may include 3 slots. For example, the HARQ-ACK field may be included in the first slot. The HARQ-ACK field carries ACK/NACK information. The CQI field carrying the channel quality indication may use two slots. For example, a 10ms radio frame may include 5 subframes.

The introduced multi-carrier operation introduces the need for additional feedback mechanisms. If the network transmits on more than two carriers simultaneously, the WTRU needs to be able to acknowledge all carriers and also be able to send CQI feedback for all configured carriers.

In addition, current HARQ acknowledgement codebooks only allow WTRUs to provide DL feedback for up to two carriers or up to four streams in case MIMO is configured in conjunction with dual carrier operation.

The composite HARQ response message to be transmitted may be encoded into 10 bits as shown in table 2, which table 2 is a codebook table used when dual carrier downlink operation is combined with MIMO. Here, 'a' means 'ACK', 'N' means 'NACK', and 'D' means 'no transmission' (i.e., Discontinuous Transmission (DTX)). 'AA', 'AN', 'NA', and 'NN' refer to feedback for dual stream transmission in a cell. For example, 'AN' means ACK on the primary stream and NACK on the secondary stream. Marking the output as w₀、w₁、...、w₉。

Table 2 shows channel coding of HARQ-ACK in case dual carriers and MIMO are configured.

TABLE 2

Fig. 3 illustrates an example wireless communication system 100 in which a single carrier 160 is used to handle uplink transmissions and multiple carriers 170 are used to handle downlink transmissions. The wireless communication system 100 includes a plurality of WTRUs 110, a node-B120, a Controlling Radio Network Controller (CRNC)130, a Serving Radio Network Controller (SRNC)140, and a core network 150. The node-B120 and the CRNC 130 may be collectively referred to as a UMTS Terrestrial Radio Access Network (UTRAN).

As shown in fig. 3, the WTRU 110 communicates with a node-B120, the node-B120 communicating with both the CRNC 130 and the SRNC 140. Although three WTRUs 110, one node-B120, one CRNC 130, and one SRNC 140 are shown in fig. 3, it should be noted that any combination of wireless and wired devices may be included in the radio communication system 100.

Fig. 4 illustrates an example wireless communication system 200 in which multiple carriers 260 are used for uplink transmissions and multiple carriers 270 are used for downlink transmissions, according to an example embodiment. The wireless communication system 200 includes a plurality of WTRUs 210, a node-B220, a CRNC230, an SRNC 240, and a core network 250. The node-B220 and the CRNC230 may be collectively referred to as UTRAN.

As shown in fig. 4, the WTRU 210 communicates with a node-B220, the node-B220 communicating with both the CRNC230 and the SRNC 140. Although three WTRUs 110, one node-B120, one CRNC 130, and one SRNC 140 are shown in fig. 4, it should be noted that any combination of wireless and wired devices may be included in the radio communication system 200.

Figure 5 is a functional block diagram of a WTRU410 and a node-B420 of the wireless communication system 200 of figure 4. As shown in fig. 5, a WTRU410 communicates with a node-B420, and both are configured to perform the following method: where uplink transmissions from the WTRU410 are transmitted to the node B420 using multiple uplink carriers 460. The WTRU410 includes a processor 415, a transmitter 416, a receiver 417, memory 418, an antenna 419, and other components (not shown) that may be found in a typical WTRU. The antenna 419 may include multiple antenna elements or multiple antennas may be included in the WTRU 410. Memory 418 is provided to store software including an operating system, application programs, and other similar functions. The processor 415 is provided to perform a method of uplink transmission using multiple uplink carriers, alone or in combination with software and/or any one or more components. The receiver 417 and the transmitter 416 are in communication with the processor 415. The receiver 417 and the transmitter 416 can receive and transmit simultaneously on one or more carriers. Alternatively, multiple receivers and/or multiple transmitters may be included in the WTRU 410. The antenna 419 is in communication with the receiver 417 and the transmitter 416 to facilitate the transmission and reception of wireless data.

node-B420 includes a processor 425, a transmitter 426, a receiver 427, a memory 428, an antenna 429, and other components (not shown) that may be found in a typical base station. The antenna 429 may include multiple antenna assemblies or multiple antennas may be included in the node-B420. Memory 428 is provided to store software including an operating system, application programs, and other similar functions. The processor 425 is provided with a method to perform uplink transmission using multiple uplink carriers, alone or in combination with software and/or any one or more components. The receiver 427 and the transmitter 426 are in communication with the processor 425. The receiver 427 and the transmitter 426 are capable of receiving and transmitting simultaneously on one or more carriers. Alternatively, multiple receivers and/or multiple transmitters may be included in node-B420. An antenna 429 is in communication with the receiver 427 and the transmitter 426 to facilitate the transmission and reception of wireless data.

It should also be noted that although embodiments are described herein with reference to channels associated with 3GPP release 4 to release 9, it should be noted that the embodiments are applicable to further 3GPP releases (and channels used herein), such as 3GPP Long Term Evolution (LTE) and any other type of wireless communication system, and channels used herein. It should also be noted that the embodiments described herein may be applied in any order or in any combination.

Feedback mechanisms and methods are disclosed herein that allow/initiate reception of multiple downlink transmissions and increase the efficiency of multi-carrier operation. The different embodiments described may be used alone or in any combination.

In one embodiment, when the WTRU410 is configured with dual carrier operation in the UL, the WTRU410 may also be configured with a primary/anchor UL carrier and a secondary UL carrier. The anchor/primary UL carrier may be referred to as an UL carrier associated with the anchor DL carrier. In accordance with dual-cell UL operation, the WTRU410 may be configured with two DL cells consisting of the same set of channels as the previously defined serving HS-DSCH cell, i.e., the fractional dedicated channel (F-DPCH), the enhanced dedicated channel (E-DCH) HARQ acknowledgement indicator channel (E-HIGH), the E-DCH relative grant channel (E-RGCH), and the E-DCH absolute grant channel (E-AGCH). The WTRU410 may be configured with two anchor cells or two primary cells, each cell associated with a UL carrier. If one of the two anchor cells contains a larger subset of channels, that cell may also be referred to as the primary anchor carrier, while the other carrier may be referred to as the secondary anchor carrier.

The methods described below will describe multi-carrier downlink operation for three carriers or four carriers. It will be appreciated that the carriers may be located in the same frequency band or in different frequency bands. Furthermore, it is important to note that multi-carrier operation may be applied to more than four carriers.

The network may configure the WTRU410 with multiple carriers (e.g., carrier-1 through carrier-n). For each carrier, there may be an associated feedback message (e.g., HARQ 1-n and CQI 1-n), respectively. These carriers are labeled 1 through n when described below. However, the marking of the carriers does not mean that the carriers are marked in the order of their frequency allocations. The cells/frequencies may be mapped to carrier-1 to carrier-n according to any one or a combination of the following: explicit configuration by the network, where each frequency is explicitly indicated by a carrier number (e.g., carrier-1 through carrier-n may be numbered according to the order provided by the configuration); carriers-1 through-n may be numbered in increasing or decreasing order according to frequency value (or channel number, e.g., using the Universal Terrestrial Radio Access (UTRA) absolute radio frequency channel number (UARFCN)); the first carrier may always correspond to the anchor carrier; the first two carriers may correspond to two anchor carriers; when more than one anchor carrier is configured, odd numbered carriers may correspond to the anchor carrier; or the carriers may be configured according to the frequency band.

The WTRU410 may be configured to use a dual carrier uplink control channel and a single carrier uplink control channel (e.g., HS-DPCCH). In one embodiment, the WTRU410 is configured to provide feedback for additional DL carriers on additional uplink control channels. For example, when the WTRU410 is configured for dual carrier operation in the UL, the WTRU410 may be configured to provide feedback on a UL physical control channel referred to as the HS-DPCCH2, which HS-DPCCH2 is transmitted on a secondary uplink carrier. In another example, the WTRU410 may be configured to provide feedback on an UL physical control channel called HS-DPCCH2, which HS-DPCCH2 may transmit on the same UL carrier as a conventional HS-DPCCH using a different channelization code and possibly a different in-phase/quadrature (I/Q) branch (branch). The HS-DPCCH format and channelization codes and I/Q branch mapping defined for HSDPA operation are referred to as HS-DPCCH 1.

The WTRU410 may be configured to transmit additional uplink control channels (e.g., HS-DPCCH2) using additional channelization codes and possibly mapped to different I/Q branches. In one embodiment, the HS-DPCCH1 and the HS-DPCCH2 are transmitted in the same UL carrier. This ensures that multi-carrier operation can run regardless of the number of UL carriers. The WTRU410 may transmit the uplink control channel on a single Transmission Time Interval (TTI) or on consecutive TTIs.

In another alternative embodiment, the WTRU410 may be configured such that an additional UL scrambling code carries a control channel, such as the HS-DPCCH 2.

The WTRU410 transmits ACK/NACK and CQI feedback for the first two carriers on the HS-DPCCH 1. However, when one or more additional carriers are configured, the WTRU410 transmits ACK/NACK and CQI feedback for the additional carriers on an additional uplink control channel (e.g., HS-DPCCH 2).

Each additional uplink control channel (e.g., HS-DPCCH2) provides ACK/NACK and CQI feedback for one or more additional DL carriers. If there are more than two additional carriers, the WTRU410 may use additional channelization codes, or, optionally, additional UL scrambling codes, for the HS-DPCCH3 and additional uplink control channels. According to this embodiment, the WTRU410 may use x dual HS-DPCCHs, where x is equal to the number of DL carriers divided by two (rounded up to the next largest integer).

Fig. 6 shows a format and channel coding for providing feedback information to additional carriers using at least one new physical control channel.

The format and channel coding of the HS-DPCCH2 (or HS-DPCCH x for the case of n > 4) may depend on the number of additional carriers pending in the system. More particularly, if there is one additional carrier (i.e., three carriers in total or an odd number of carriers when n > 4), the WTRU410 reports a single ACK/NACK and CQI report on the HS-DPCCH2 (or HS-DPCCHx). When MIMO is not configured, the HARQ response message and the channel quality indication may be encoded using the current single carrier channel coding for HS-DPCCH. If two additional carriers are configured (or an even number of carriers when n > 4), the WTRU410 uses the channel coding for the HS-DPCCH when there is a secondary cell (i.e., the HS-DPCCH channel coding for the current dual-cell operation). In addition, when n > 4, HS-DPCCH (x-1) can be configured with dual cell channel coding.

The channelization code and I/Q branches for the HS-DPCCH2 may be designed to minimize the cubic metric.

In an alternative embodiment, the WTRU410 is configured to operate in more than one UL carrier. So that HS-DPCCH1 and HS-DPCCH2 may be transmitted on different UL carriers. For example, HS-DPCCH1 may be transmitted on the anchor/primary UL carrier, while HS-DPCCH2 may be transmitted on the secondary carrier. In this example, the HS-DPCCH channelization codes and I/Q branches may be the same for both HS-DPCCH formats, but transmitted on different frequencies.

The WTRU410 may transmit using multiple carriers and then switch to transmitting via a single carrier. If the secondary UL carrier is disabled or deactivated and multi-carrier operation continues, the WTRU410 may be configured to revert back to providing feedback in the same manner as in single carrier operation. Thus, the WTRU410 may autonomously switch the transmission of the HS-DPCCH2 to the anchor carrier. The handover may be performed, for example, by using additional channelization codes, on different scrambling codes, or by using another single carrier approach (e.g., using the embodiments described herein). Similarly, when the secondary UL carrier is activated and activated or reactivated, the WTRU410 may continue to transmit the HS-DPCCH2 using additional channelization codes, or alternatively, according to a different scrambling code defined on the anchor carrier. Optionally, when the WTRU410 transmits on two carriers in the UL (in which case each group of DL carriers may have an associated HS-DPCCH on the UL carrier paired with the DL carrier belonging to the group), multi-carrier operation may be configured and/or performed. For example, for n DL carriers, the WTRU410 may need x UL carriers to transmit x HS-DPCCHs associated with each pairing of DL carriers.

The carrier pairing associated with each HS-DPCCH may be defined or preconfigured by the network according to any one or combination of the following: the network may explicitly use Radio Resource Control (RRC) signaling to configure the mapping from carriers to HS-DPCCH; the network may have a predetermined mapping from carrier to HS-DPCCH based on the order of DL frequencies provided in the configuration; carrier-1 and carrier-2 may always correspond to the primary carrier/anchor DL carrier and the first adjacent frequency of the primary carrier, respectively, while carrier-3 and carrier-4 may correspond to the remaining secondary carriers of the WTRU410 and be defined in terms of the frequencies provided or the order of the configurations provided; carrier-1 and carrier-2 may correspond to the primary anchor carrier and the secondary anchor carrier, while carrier-3 and carrier-4 may correspond to the secondary anchor carrier and the neighboring carrier associated with the frequency; carrier-1 and carrier-2 may correspond to two DL anchor/primary cells (if there are two DL anchor carriers as defined above), while carrier-3 and carrier-4 correspond to secondary carriers, thereby allowing the network to disable the secondary carriers associated with each primary carrier; carrier-1 and carrier-2 correspond to an anchor carrier and a secondary carrier associated with an UL carrier in which HS-DPCCH1 is being transmitted, while carrier-3 and carrier-4 correspond to an anchor frequency and a secondary frequency of a secondary UL carrier in which HS-DPCCH2 is being transmitted; the HS-DPCCHs may be band-dependent such that when the carriers are on different frequency bands, one HS-DPCCH is used in each band (e.g., if there are two carriers on each band, the WTRU410 uses one HS-DPCCH for each band, and if there are three carriers on one band, the WTRU410 uses three HS-DPCCHs), but if two or fewer transmissions are detected, the first HS-DPCCH may send a report regardless of which carrier is transmitting; or the HS-DPCCH may be used to carry information of the primary cell (i.e., the cell associated with the UL carrier if it is transmitted), thereby allowing the network to disable the secondary carrier associated with each primary carrier. The described example is for the case of four DL carriers (mapped to two HS-DPCCHs), but it should be understood that the description may also be applied to three or more carriers in general.

The WTRU410 may also be configured to perform flexible mapping from carriers to uplink control channels (e.g., HS-DPCCH). In a multi-carrier system, the WTRU410 may be configured to transmit HARQ and CQI for each carrier. For example, in a four carrier system, the WTRU410 may transmit up to four HARQ feedbacks (i.e., HARQ1, HARQ2, HARQ3, HARQ4) and up to four CQI feedbacks (i.e., CQ1, CQ2, CQ3, CQ 4). The WTRU410 may be configured to dynamically adjust the amount and type of feedback based on the received DL transmission. For example, the WTRU410 may be configured to transmit only on a particular uplink control channel if a corresponding downlink transmission is received. When the WTRU410 transmits on an additional UL physical control channel (i.e., HSDPCCH), the WTRU410 is configured to determine the optimal or preferred channelization code. The optimal or preferred channelization code may be signaled by the network or determined by the WTRU410 based on, for example, minimizing power ratio (ratio), power backoff, or maximizing power headroom. Feedback for carriers i and j is carried on the HS-DPCCH x using a fixed mapping from carrier to HS-DPCCH, where the mapping for carriers i, j, and x is fixed. That is, at most two downlink carriers correspond to each HS-DPCCH.

Table 3 shows possible combinations of HARQ and CQI feedback in a four carrier system. Since HARQ and CQI feedback are not correlated, one of sixteen possible CQI feedback information will be used for each HARQ feedback combination. "Y" in table 3 indicates that feedback is transmitted, and "N" in table 3 indicates that feedback is not transmitted.

TABLE 3

Table 3 shows two different feedback combinations: combination a and combination B. In the portion labeled as combination a, the WTRU410 sends CQI and HARQ feedback for up to two carriers simultaneously. Thus, the WTRU410 may send all feedback using a single feedback channel (e.g., HS-DPCCH) provided that the feedback channel has flexible carrier/HS-DPCCH mapping. Flexible carrier/HS-DPCCH mapping HARQ feedback is provided for any two carriers (i, j) and CQI feedback is provided for any two carriers (m, n), where the carriers (i, j, m, n) need not be the same. The mapping associates carriers i, j (for HARQ) and m, n (for CQI) to HS-DPCCHx.

In the portion labeled as combination B, the WTRU410 sends HARQ or CQI feedback for three carriers simultaneously. The transmission of HARQ or CQI feedback for three carriers requires the WTRU410 to use two feedback channels (e.g., two HS-DPCCHs).

To provide the network with an indication of which carrier is sending feedback, the WTRU410 may signal which of the possible combinations is included in the HS-DPCCH. For example, in the case of two carriers active, there may be 121 possible combinations of (11) (11). At least seven bits may be required to signal the indication. In one embodiment, the WTRU410 signals the index of the carrier sending the feedback using HS-DPCCH channelization code number selected from a set that has been optimized for cubic metric performance. In another embodiment, the index of the carrier sending the feedback is sent in-band with the CQI and HARQ feedback. This is performed by either extending the codeword set for HARQ feedback or reducing the coding for CQI feedback.

Alternatively, the network may blindly detect the I/Q branch and the channelization codes and carriers providing CQI and HARQ feedback. For CQI feedback, the network may utilize a configured CQI feedback cycle and repetition factor to determine the carrier associated with the received feedback. For HARQ feedback, the network may utilize knowledge of the transmitted downlink and strict timing requirements for HARQ feedback to determine the carrier associated with the received feedback.

In an alternative embodiment, a single uplink control channel (e.g., HS-DPCCH) channelization code may be used to carry feedback information in a multi-carrier system. Channel coding for HARQ and CQI feedback will be described in more detail below.

Regarding HARQ feedback, more particularly for channel coding of HARQ ACK/NACK, two different channel coding implementations may be defined to operate for three or four carriers. Alternatively, a channel coding implementation may be defined for four carrier operation, and the implementation may also be directed to three carrier operation. Since there may be three or four carriers, there may be four transmissions during one TTI and up to eight transport blocks, in case dual stream MIMO operation is configured for each carrier. As a result, there are a large number of different possible feedback combinations, including PRE/POST signaling. In the case of four carriers, many bits (e.g., 7, 8, or more bits) may be needed to convey all the different possible feedback combinations.

In one embodiment, the HARQ feedback may be transmitted using a new HS-DPCCH frame format that carries ACK/NACK feedback without carrying any CQI feedback. This embodiment allows the WTRU410 to use a full subframe (i.e., space for CQI feedback) to carry ACK/NACK information bits for all three or four carriers. An example of the resulting frame format is shown in fig. 7, where two HARQ-ACK fields (e.g., HARQ1 and HARQ2) are time multiplexed in accordance with a single new HS-DPCCH frame format.

Alternatively, the CQI feedback is multiplexed with the HARQ feedback in the same HS-DPCCH code. To achieve this, the WTRU410 may be configured to adjust a Spreading Factor (SF). For example, the WTRU410 may lower the spreading factor so that more symbols are available on the HS-DPCCH, thereby essentially creating a new HS-DPCCH format. In one example of this embodiment, the WTRU410 may be configured to generate the HS-DPCCH with a frame format that uses a spreading factor of 128 instead of the conventional spreading factor of 256. Using the same frame format for three radio slots may allow transmission of twice as many control information symbols (e.g., 60 symbols versus 30 symbols) as are transmitted on the new reduced-SF HS-DPCCH. Thus, two conventional HARQ-ACK fields and two conventional CQI fields may be multiplexed into a new structure.

Fig. 8 shows an example slot structure of two consecutive subframes of the HS-DPCCH. As shown in fig. 8, a subframe of 2ms is divided into four slots. It can be seen in this example that the HARQ-ACK fields of the HS-DPCCH1 and HS-DPCCH2 may be multiplexed in the first slot of the new HS-DPCCH, while the CQI fields of the HS-DPCCH1 and HS-DPCCH2 may be multiplexed in the second slot and the third slot of the new HS-DPCCH frame format. As an alternative, conventional coding of the HARQ-ACK and CQI fields may be used.

Figure 9 shows another example of a possible HS-DPCCH frame structure with a spreading factor 128. In this example, the HS-DPCCH1 is sequentially multiplexed with the HS-DPCCH 2.

Other time multiplexing structures are also contemplated without changing the basic content described in this specification.

For CQI feedback, since the WTRU410 may be configured to receive from at most three or more DL carriers, the WTRU410 may have to transmit CQI feedback for all configured DL carriers.

Fig. 10 shows a composite CQI feedback report derived from four independent CQI reports represented by CQI1, CQI2, CQI3, and CQI4 when there are four configured DL carriers. Although each CQI feedback report in fig. 10 is shown to carry five bits, any number of bits may be used in the CQI feedback report. Furthermore, a different number of bits may be used for each CQI feedback report.

Alternatively, a composite CQI feedback report derived from four separate CQI reports may be transmitted in one HS-DPCCH together with HARQ feedback. However, this may require additional information bits to be sent on the HS-DPCCH. These additional information bits may require a change in the spreading factor or other similar signaling.

In one embodiment, CQI feedback reports are multiplexed with HARQ feedback, but not all CQI reports are concatenated and transmitted together. If the WTRU410 is unable to send three or four CQI reports in one TTI, the WTRU410 may time multiplex the different CQI reports. Alternatively, the WTRU410 may be configured to further reduce the spreading factor as described herein. In some cases, the WTRU410 may need to adjust the transmission power to account for the smaller spreading factor.

For example, the WTRU410 may send CQI reports for one carrier at a time in different subframes. More particularly, a subframe number may be reserved for a particular CQI report so that the WTRU410 may send CQI1 in the first subframe in the frame, CQI2 on the second subframe, and so on.

In an alternative embodiment, two CQI reports may be concatenated into a composite CQI report and transmitted on the HS-DPCCH in a TTI. The WTRU410 may alternate in time sending pairs of CQI reports. For example, the WTRU410 may send the connected CQI1 and CQI2 in odd subframes and the connected CQI3 and CQI4 in even subframes. In the case where CQI repetition (repetition) is configured (i.e., N _ CQI _ transmit > 1), the WTRU410 may transmit all repetitions of the connected CQI1 and CQI2 first, and then all repetitions of the connected CQI1 and CQI 2. Alternatively, the WTRU410 may transmit the connected CQI1 and CQI2 in a time-interleaved manner with the connected CQI3 and CQI4 until all repetitions are transmitted. This embodiment can be extended to different packet and time multiplexed configurations.

The WTRU410 may also be configured to reduce CQI feedback by using multiplexing. In one embodiment, the HARQ feedback for multiple carriers transmitted by the WTRU410 is combined with a reduction in the reporting frequency of the CQI feedback for each carrier. This may avoid excessive peak UL power requirements caused by feedback when multiple DL carriers are configured.

The reduction of CQI feedback overhead may be affected in several possible ways. For example, when a single UL carrier is used, the reduction in CQI overhead may allow for time multiplexing of feedback information over two consecutive subframes.

Fig. 11 shows a slot structure of two consecutive subframes of the HS-DPCCH. In one embodiment, HARQ feedback information, or CQI feedback information, or both types of feedback information may be jointly encoded over two consecutive subframes. Table 4 shows HARQ feedback that is jointly coded and related to a set of two previous consecutive subframes.

TABLE 4

As shown in table 4, there are different options for jointly coding feedback on consecutive subframes. In option 1 and option 2, HARQ feedback for up to four downlink carriers is provided with the first two slots of each subframe. The encoding of the HARQ feedback information in each slot may be the same encoding as for the dual carrier case. When there are only three carriers, one of the time slots may be encoded for a single carrier. The third slot of each subframe may be used to encode CQI information. Since CQI information typically requires two slots, half of the bits are transmitted in the first subframe and the other half of the bits are transmitted in the second subframe.

CQI coding is performed based on single-carrier or dual-carrier mechanisms, respectively, depending on whether CQI for one carrier is transmitted in each pair of subframes (option 1) or CQI for two carriers (option 2). If it is not possible to report CQI for all four carriers on a pair of subframes, the WTRU410 may be configured to report CQI for each carrier once every four pairs of subframes (option 1), or once every two pairs of subframes (option 2). A similar approach may be used in the case where there are only three carriers, except that the WTRU may be configured to report per-carrier CQI every three pairs of subframes (option 1), or every carrier CQI every two pairs of subframes in three pairs (option 2). Option 3 is similar to option 2, except that the information is spread differently over six slots.

Second, when dual UL carriers are used, the reduction in CQI overhead may allow for multiplexing of feedback information on both carriers.

When multiple UL carriers are available, the WTRU410 may be configured to transmit feedback on each of the UL carriers. However, when UL transmission power is limited, it is still important to reduce the total maximum amount of power values that need to be transmitted on all carriers during a time slot. Table 5 shows options for reducing the peak power requirement for high speed physical downlink shared channel (HS-PDSCH) feedback, where two uplink carriers are available and up to four carriers may be used in the downlink.

TABLE 5

In all four options shown in table 5, the third slot of the subframe may be used for CQI reporting on each uplink carrier. In option 1 and option 2, a CQI for one downlink carrier may be reported in each subframe. The CQI is coded in the same way as in the single (DL) carrier case, except for the case where two slots are on two different UL carriers. In option 3 and option 4, CQIs for two downlink carriers may be reported in each subframe. The CQI is coded in the same way as in the dual carrier case, except for the case where two slots are on two different UL carriers. In option 1 and option 3, HARQ feedback is reported for two downlink carriers in each slot, while the same coding is used on one UL carrier as already defined for the dual DL carrier case. In option 2 and option 4, HARQ feedback is also reported for both downlink carriers in each slot, while normal HARQ feedback for the single DL carrier case is used on both UL carriers.

The WTRU410 may also be configured to reduce CQI feedback using autonomous transmission. When the WTRU410 is configured with more than N DL carriers (e.g., N > 2), the network may configure the WTRU410 to autonomously determine when to transmit CQI for each of the carriers. Since the value of the CQI for the WTRU410 may be relatively constant over a short period of time, the network may receive little or no additional information from the repeated CQI values. Thus, the WTRU410 may be configured to determine the feedback period and repetition factor. Alternatively, the network may signal the feedback period and repetition factor.

The WTRU410 may monitor the quality of all carriers and transmit a new CQI if the quality of one of the carriers changes by more than a predetermined threshold or a predetermined increment. The quality may be based on a measured common pilot channel (CPICH) energy/power density (EcNo), CPICH Received Signal Code Power (RSCP), or calculated CQI for each slice in the band. The delta and quality metric may be preconfigured by the network, signaled through system information, or provided with HS-DSCH configuration information. Alternatively, these parameters may be the same for all carriers or may be specific for each carrier.

If the WTRU410 determines that more than one carrier requires CQI updates during a subframe, the WTRU410 may decide to perform any one or a combination of the following. The WTRU410 may transmit the CQI for the carrier whose quality (cpich ecno, CPICH RSCP, or calculated CQI) has experienced the greatest change. The WTRU410 may transmit the CQI for the carrier that may be most affected by using the old CQI (e.g., in the case where the carrier-1 supports a transport block that is larger than that reported at the last CQI transmission while the carrier-2 supports a transport block that is smaller than that reported at the last CQI transmission, the WTRU410 may decide to send the CQI for carrier-2 even if the quality measurement for carrier-2 changes less than the quality measurement for carrier-1, and transmission on carrier-1 may continue all the time but at a lower rate than that supported by the WTRU 410). The WTRU410 may make a decision based on the type of traffic it is receiving (e.g., if the WTRU410 is receiving DL traffic, the WTRU410 may prioritize a Dedicated Control Channel (DCCH) over a Dedicated Traffic Channel (DTCH)). Or the WTRU410 may transmit more than one CQI in a single HS-DPCCH.

Since the CQI transmission is spontaneous, the network no longer knows the association between the reported CQI and the carrier associated with the reported CQI. To establish a link between the reported CQI and the carrier, the WTRU410 may include carrier index information in the uplink control channel feedback (e.g., HS-DPCCH). For example, the WTRU410 may transmit a two-bit carrier index with the reported CQI. The reported CQI may be reduced to accommodate additional information. Alternatively, the coding on the CQI may be reduced to accommodate the additional information. Further, in subframes where HARQ feedback is not required, the WTRU410 may use the HARQ-ACK field to indicate the carrier index, e.g., by using one of four reserved codewords, each associated with a particular carrier index.

In this embodiment, the WTRU410 may be configured to repeat the CQI. If the WTRU410 is required to transmit a new CQI (for a different carrier) while the WTRU410 may need to transmit a duplicate old CQI, the WTRU410 may define and apply rules to prioritize one transmission over another. For example, according to one rule, the WTRU410 may be configured to prioritize a new CQI so that it is transmitted before other CQIs (absolute priority of new CQI). In another rule, the WTRU410 may be configured to transmit a new CQI only if a predetermined minimum time interval has elapsed between the first time instance of the repeated CQI and the transmission of the new CQI (possibly from a different carrier). Since the WTRU410 transmits the CQI autonomously, the interval between repeated transmissions may be left to the WTRU410, where each transmission requires an indication of the carrier. Alternatively, the transmission interval may be pre-configured, provided in system information, or transmitted with the HS-DSCH information.

The WTRU410 may also be configured to reduce CQI feedback through multiplexing and autonomous transmission. In this embodiment, the WTRU410 may be configured to time multiplex the feedback on two consecutive subframes. The embodiments described below are made with reference to option 1 as an example, but these embodiments can also be generalized to options 2 and 3. The WTRU410 may send HARQ feedback for four carriers in the first two slots of each subframe and CQI feedback on every two consecutive subframes (e.g., in the third slot of each of these subframes). The CQI transmitted over these two subframes may be a CQI for a single carrier that has been autonomously determined by the WTRU 410. The carrier indication is provided to the network by using a reserved codeword of four slots for carrying HARQ feedback. Each of the time slots carries HARQ feedback for two DL carriers. If the WTRU410 is transmitting CQI for carrier K, a specific or unique set of codewords may be used for slot K (K ═ 1, 2, 3, 4). The network blindly detects the use of a particular set of codewords in a slot and uses the slot index to determine the carrier to which the CQI belongs.

In an alternative embodiment, multiple uplink control channel codes are used to transmit feedback separately (e.g., two HS-DPCCH codes for HARQ feedback and CQI feedback, respectively). Two HS-DPCCH formats are defined to carry the CQI feedback and HARQ feedback on the two HS-DPCCHs. For example, one HS-DPCCH uses the entire subframe to transmit the HARQ-ACK field for all four or three carriers to carry the information. The HARQ feedback may be jointly coded or separately coded.

Alternatively, the separately jointly encoded HARQ feedback may be sent on the HS-DPCCH 1. For example, the HARQ1 field contains HARQ feedback for carrier-1 and carrier-2, which is jointly encoded. The HARQ2 field contains HARQ feedback for carrier-3 and carrier-4, which is jointly encoded. In the case of three carriers, HARQ1 may be jointly coded for carrier-1 and carrier-2, while HARQ2 may contain HARQ feedback for carrier-3 separately. For the case where the number of carriers N > 4, the WTRU410 may contain x HARQ fields that are coded in pairs, where x is equal to an integer rounded up by N/2.

Fig. 12 shows an example embodiment in which three CQI reports are concatenated together. The second HS-DPCCH code is used to send CQI reports for up to four carriers in one full subframe. The CQI composite is composed of CQI1, CQI2, CQI3, and CQI4 connected together.

The channelization codes and I/Q branches for the second HS-DPCCH may be designed to minimize the cubic metric. The first HS-DPCCH channelization code and branch may be for HS-DPCCH.

The HS-DPCCH1 and HS-DPCCH2 may be transmitted in the same UL carrier. This may ensure that multicarrier operation may be run regardless of the number of UL carriers. Alternatively, if the WTRU410 is configured to operate in more than one UL carrier, the HS-DPCCH1 and the HS-DPCCH2 may be transmitted in different UL carriers.

Fig. 13 shows an example embodiment where the HS-DPCCH1 is transmitted on the serving/primary UL carrier and the HS-DPCCH2 is transmitted on the secondary carrier. In this case, the HS-DPCCH channelization code and the I/Q branch may be the same for both HS-DPCCH formats, but transmitted on different frequencies. In the case where the secondary UL carrier is disabled and multi-carrier DL operation continues, the WTRU410 may start transmitting the HS-DPCCH2 according to the additional channelization codes defined on the anchor carrier. When the WTRU410 activates (or reactivates) the secondary uplink carrier, it may transmit the HS-DPCCH2 on the secondary uplink carrier as described herein. The WTRU410 transmits an additional set of HS-DPCCH or control channels using a conventional channelization code and I/Q branch, but using a specific and different scrambling code.

In an alternative embodiment, the WTRU410 may use a second UL scrambling code to send feedback information for a different downlink carrier. The network configures each additional physical uplink control channel (e.g., HS-DPCCH) or set of control channels needed for the WTRU410 using a different scrambling code.

The format of the control information transmitted using the second scrambling code may be similar to the format defined for dual cell operation, which allows transmission of two cell HARQ feedback and two cell CQI reports. Alternatively, the format may be according to any of the embodiments described herein.

The feedback channel may be configured by the network or implicit based on the DL configuration.

When the WTRU410 is configured with three or four downlink carriers without MIMO and with one UL carrier, the control channel for dual carrier operation (e.g., HS-DPCCH for DC-HSDPA) may provide feedback for two of the three or four carriers. Additional control channels (e.g., additional HS-DPCCH) may be reported (using additional channelization codes, finger pairing, and/or using additional scrambling codes) for the remaining carriers. In the case where three DL carriers are configured, a legacy control channel (e.g., legacy HS-DPCCH) may be used to report feedback for the remaining channels. In the case where four DL carriers are configured, the control channel for dual carrier operation (e.g., HS-DPCCH for DC-HSDPA) may be used to provide feedback for the remaining two carriers. The mapping between UL and DL carriers may be implicit or signaled by the network. Each control channel (e.g., HS-DPCCH) may be configured with a different transmit power offset.

When the WTRU410 is configured with three or four downlink carriers without MIMO and has two UL carriers, the HS-DPCCH for DC-HSDPA on the UL anchor carrier provides feedback for two of the three or four carriers. Additional control channels (e.g., additional HS-DPCCH) are used for reporting on the UL secondary carrier for the remaining carriers. In the case where three DL carriers are configured, a legacy control channel (e.g., HS-DPCCH) may be used to report feedback for the remaining channels. For example, where four DL carriers are configured, a control channel for dual carrier communication (e.g., HS-DPCCH for DC-HSDPA) may be used to provide feedback for the remaining two carriers. The mapping between UL and DL carriers is implicit or signaled by the network. Each control channel (e.g., HS-DPCCH) may be configured with a different transmit power offset.

When the WTRU410 is configured with two downlink carriers and MIMO and two UL carriers, a high speed control channel (e.g., HS-DPCCH for MIMO operation) on the UL anchor carrier may provide feedback for the downlink anchor carrier. A high speed control channel for the secondary UL carrier (e.g., HS-DPCCH for MIMO operation on the UL secondary carrier) may be used to provide feedback for the downlink secondary carrier. Each HS-DPCCH may be configured with a different transmit power offset.

In another embodiment, a method of optimizing a feedback controlled HARQ acknowledgement codebook is disclosed as follows in the context of simultaneous multi-carrier high speed downlink operation.

For each HARQ transmission of the HS-DSCH for each Transmission Time Interval (TTI), the WTRU410 receiver may display the following status. The receiver (or equivalently the WTRU 410) may send an ACK if it correctly receives the HS-SCCH and the data packets associated with the HS-PDSCH. The receiver may send a NACK if the receiver correctly received the control information from the HS-SCCH but detected an error in the data packet. The receiver may declare DTX if it does not detect an HS-SCCH matching the Identity (ID) assigned to the current WTRU410 in the present TTI. For the DTX state, the following may occur: the node-B420 does not send any data to the WTRU410 in the current TTI, or the WTRU410 receiver fails to decode the HS-SCCH addressed to the WTRU 410.

For LTE, similar to High Speed Packet Access (HSPA), the WTRU410 receiver 417 may display the following status for each HARQ transmission of the Physical Downlink Shared Channel (PDSCH) for each Transmission Time Interval (TTI). The receiver (or equivalently the WTRU 410) may generate an ACK if it correctly receives a Physical Downlink Control Channel (PDCCH), and a data packet associated with the PDCCH. If the receiver 417 correctly receives the control information from the PDCCH, but detects an error in the data packet, the receiver may generate a NACK. If no PDCCH control signaling is detected for the WTRU410 in the present TTI, the associated control information is not transmitted on the Physical Uplink Control Channel (PUCCH) (i.e., DTX). By not occupying PUCCH resources when no valid PDSCH related control signaling is detected, the enodeb 420 is able to perform detection of three states: ACK, NACK, or DTX. On the condition that the WTRU410 has a valid uplink scheduling grant in the current TTI, the HARQ acknowledgement is time multiplexed with the data and transmitted on the Physical Uplink Shared Channel (PUSCH) instead of the PUCCH.

When multi-carrier downlink operation is configured, the composite acknowledgement message is represented by the HARQ-ACK state to indicate the HARQ state of the carrier, which is formed by the letters of the separator "/" divided A, N, or D, where "a" means "ACK", "N" means "NACK", and "D" means "no transmission" (i.e., DTX). If MIMO is configured, there may be two letters between the delimiters for dual stream transmission in the carrier. For example, a/NA/D carries HARQ acknowledgement messages for three carriers, where the second carrier is configured for MIMO. It should be noted that a carrier can be treated equally and identified by its position in the message. For example, they are not distinguished by "primary", "secondary", or "secondary" carriers.

Since transmissions are made on multiple carriers (e.g., three or four carriers) in the same TTI, the total number of data streams may increase in addition to the possible dual stream operation at each carrier that may result from MIMO configurations. The number of total data streams may result in a larger set of feedback combinations in the HARQ-ACK state codebook. For example, in a network using two or more carriers, the number of states may increase to eight (e.g., for HSPA) or more (e.g., in LTE/LTE-advanced), which may result in a larger set of different feedback combinations of HARQ-ACK states in the codebook. Carrier aggregation, in which two or more carriers are aggregated, may be implemented in LTE-advanced to support wider transmission bandwidths (e.g., up to 100 MHz). LTE-advanced may support more than five downlink component carriers. Thus, ACK/NACK corresponding to the downlink component carrier transport block may be transmitted in the uplink. For example, assuming that MIMO spatial multiplexing configuration is performed for two transport blocks for each component carrier, the total number of ACK/NACKs to be transmitted in the uplink may be ten.

To reduce the size of the HARQ-ACK codebook table while minimizing the impact on the downlink transmission performance, the WTRU410 may be configured with a state reduction device. Figure 14 illustrates state reduction functions that may be implemented in the WTRU 410. The state reduction function may map the actual HARQ-ACK states to a smaller set of reported HARQ-ACK states. As a result of the state reduction function, the number of codewords in the channel coding is smaller, which may allow for better coding efficiency. The state reduction function may be preconfigured, signaled by the network, or dynamically determined by the WTRU410 based on the state.

The state reduction function may be implemented according to one or any combination of the following embodiments.

In one embodiment, the WTRU410 may be configured to perform a grouped DTX reporting method. The WTRU410 groups a set of carriers or data flows. If the WTRU410 detects DTX from any of the carriers or any of the data streams, DTX is declared on all other carriers or data streams regardless of the HARQ-ACK status of the other carriers or data streams in the packet. Alternatively, if the WTRU410 detects a certain number of DTX states from any of the carriers or any of the data streams, the WTRU410 announces DTX on all other carriers or data streams regardless of the HARQ-ACK states of the other carriers or data streams in the packet. This embodiment may be referred to as a packet DTX reporting method.

In another embodiment, the WTRU410 may be configured to perform a network signaling method. The WTRU410 may be configured to perform state reduction conditionally based on signaling received from the network. The WTRU410 may map the HARQ acknowledgement state differently to other states based on signaling received from the network (e.g., on a per-TTI basis). An example of the signaling may be an indication of a number of transport blocks being transmitted in a current TTI or set of TTIs.

In another embodiment, node-B420 may be configured to perform a restricted transmission method. A set of carriers may be grouped and "no data transmission" is allowed at node-B420 transmitter 427 on a per-TTI or group-TTI basis on all carriers within the set simultaneously. Within a set, rules are set to limit the transmission state combinations of the carriers in the set. In particular, all transmissions or all non-transmission combinations are allowed. No-transmission combinations on only a part of the carriers are not allowed. For example, in the case of four carriers (e.g., C1, C2, C3, C4), the carriers may be grouped into sets, where set 1 includes C1/C2, and set 2 includes C3/C4. The node-B420 may be configured with rules for each set such that carrier C1 and carrier C2 may be each set for transmission, or each set for no-transmission. Thus, the signaling is reduced because if carrier C1 is set for transmission, this means carrier C2 is set for transmission, and vice versa. It should be appreciated that although the example is for four carriers and two packets, any number of carriers with any number of components in each packet may be used. An alternative embodiment is that the HS-SCCH is sent if the other carriers in the set are transmitting even if there is no data to transmit in one carrier. Thereby, the number of possible HARQ-ACKs to be transmitted can be effectively reduced. This approach may be referred to as a method of restricted transmission from node-B420.

In another embodiment, the WTRU410 may also be configured to provide NACK reporting of the packet. A set of carriers or data streams are grouped and if one NACK is detected (or a certain number of NACKs are detected) from any one of the carriers or any one of the data streams, a NACK is declared on all other carriers or data streams in the group regardless of their HARQ-ACK status. Alternatively, if a NACK is detected from any one of the carriers or any one of the data streams, a NACK is announced on all other carriers or data streams having an ACK status detected.

In another embodiment, the WTRU410 may be configured to provide a conditional DTX report transitioning from a NACK. Depending on the status of the other carriers, if a NACK is detected on a carrier or data stream, the NACK is converted to a DTX to report. The conditions for the transition may be one or any combination of the following: if the number of DTX states in all carriers or data streams is greater than a certain value; if the number of NACK states in all carriers or data streams is greater than a certain value; and/or if the number of ACK states in all carriers or data streams is less than a specified or configured value. Setting the condition identifies states having a smaller probability of occurrence, thereby minimizing the impact on downlink performance due to state simplification.

In another embodiment, the WTRU410 may be configured to provide a conditional NACK report that transitions from an ACK. Depending on the status of the other carriers, if an ACK is detected on a carrier or data stream, it is converted to a NACK for reporting. The conditions for the transition may be one or any combination of the following: if the number of DTX states in all carriers or data streams is greater than a certain value; if the number of NACK states in all carriers or data streams is greater than a certain value; and/or if the number of ACK states in all carriers or streams is less than a particular or configured value.

It should be noted that the method is generally applicable to any number of carriers performing any form of MIMO combining that can create a vast number of unlisted designs of optimized codebooks for HARQ acknowledgements.

Table 6 shows possible combinations of HARQ-ACK states for four carriers for which MIMO is not configured. Simultaneous transmission on four carriers may result in a total number of HARQ-ACK states in the codebook equal to 3⁴-1 ═ 80, as shown in table 6.

TABLE 6

D/D/D/A

D/A/D/N

D/N/A/D

A/D/A/A

A/A/A/N

A/N/N/D

N/D/N/A

N/A/N/N

D/D/D/N

D/A/A/D

D/N/A/A

A/D/A/N

A/A/N/D

A/N/N/A

N/D/N/N

N/N/D/D

D/D/A/D

D/A/A/A

D/N/A/N

A/D/N/D

A/A/N/A

A/N/N/N

N/A/D/D

N/N/D/A

D/D/A/A

D/A/A/N

D/N/N/D

A/D/N/A

A/A/N/N

N/D/D/D

N/A/D/A

N/N/D/N

D/D/A/N

D/A/N/D

D/N/N/A

A/D/N/N

A/N/D/D

N/D/D/A

N/A/D/N

N/N/A/D

D/D/N/D

D/A/N/A

D/N/N/N

A/A/D/D

A/N/D/A

N/D/D/N

N/A/A/D

N/N/A/A

D/D/N/A

D/A/N/N

A/D/D/D

A/A/D/A

A/N/D/N

N/D/A/D

N/A/A/A

N/N/A/N

D/D/N/N

D/N/D/D

A/D/D/A

A/A/D/N

A/N/A/D

N/D/A/A

N/A/A/N

N/N/N/D

D/A/D/D

D/N/D/A

A/D/D/N

A/A/A/D

A/N/A/A

N/D/A/N

N/A/N/D

N/N/N/A

D/A/D/A

D/N/D/N

A/D/A/D

A/A/A/A

A/N/A/N

N/D/N/D

N/A/N/A

N/N/N/N

The following example conditionally simplifies the DTX and reporting status of a packet based on signaling received from the network while optimizing the codebook for four carriers. The four carriers represented by C1, C2, C3, C4 are grouped into two pairs: (C1/C2) and (C3/C4). The order of the carriers has no priority. Any other combination is possible as long as the sets are formed in pairs. Second, it may be assumed that the network may be configured to transmit one or more bits to the WTRU410 for each pair of carriers, the one or more bits indicating whether data transmission is performed on both carriers or a single carrier of a pair of carriers. The reduced mapping is performed for each pair of carriers according to the following procedure. If there is a DTX in a pair of carriers and network signaling indicates dual carrier transmission on the pair of carriers, the DTX is reported on both carriers. For example, (D/A)/(A/N) may be changed to (D/D)/(A/N), which may be simplified to (D)/(A/N). If there is a DTX in a pair of carriers and the network signaling indicates a single carrier transmission on the pair of carriers, the "true" state from the other carriers is repeated. For example, (D/A)/(A/N) may be changed to (A/A)/(A/N). Both sides may be aware of the single carrier transmission. Otherwise, the state remains unchanged.

Since one HS-SCCH may be shared by dual data streams in MIMO mode, configuring the MIMO-equipped WTRU410 may indicate to use a similar reduction mechanism in its HARQ-ACK codebook design. Thus, it can be concluded that the downlink performance loss introduced by the above method can be in a range similar to a system configured with MIMO.

Table 7 shows a conditional mapping for a single pair, where dual TX means that the condition is that network signaling indicates dual carrier transmission, and single TX means that the condition is that data transmission is performed on one carrier in the pair.

TABLE 7

The HARQ-ACK state for the composite report for all carriers is obtained by applying a mapping to each of the pairs individually according to table 6 and then connecting. As a result of the optimization, the codebook size is reduced from 80 to 24 because there are only 24 remaining pending states, as shown in table 8.

TABLE 8

(A/A)/(A/A)	(A/N)/(A/N)	(D/D)/(N/A)	(N/A)/(N/N)
				(A/A)/(A/N)	(A/N)/(D/D)	(D/D)/(N/N)	(N/N)/(A/A)
(A/A)/(D/D)	(A/N)/(N/A)	(N/A)/(A/A)	(N/N)/(A/N)
				(A/A)/(N/A)	(A/N)/(N/N)	(N/A)/(A/N)	(N/N)/(D/D)
(A/A)/(N/N)	(D/D)/(A/A)	(N/A)/(D/D)	(N/N)/(N/A)
				(A/N)/(A/A)	(D/D)/(A/N)	(N/A)/(N/A)	(N/N)/(N/N)

The mapping can be changed by adding states as shown in table 9. Table 9 shows a mapping table for reusing a single pair of existing codebooks.

TABLE 9

Thus, the resulting codebook status reported to node-B420 may be obtained in Table 10. Table 10 shows the reported HARQ-ACK states that may use the binary coding scheme specified in table 2, which may be used to encode the states given in table 10 to produce the ten-bit HARQ-ACK message carried by the HS-SCCH.

Watch 10

(A/N)/(A/N)	(A )/(A )	(A/A)/(A/A)	(D )/(N )	(N )/(N/A)	(N/A)/(N/N)
						(A/N)/(D)	(A )/(A/A)	(A/A)/(A/N)	(D )/(N/A)	(N )/(N/N)	(N/N)/(A )
(A/N)/(N)	(A )/(A/N)	(A/A)/(D )	(D )/(N/N)	(N/A)/(A )	(N/N)/(A/A)
						(A/N)/(N/A)	(A )/(D )	(A/A)/(N )	(N )/(A )	(N/A)/(A/A)	(N/N)/(A/N)
(A/N)/(N/N)	(A )/(N )	(A/A)/(N/A)	(N )/(A/A)	(N/A)/(A/N)	(N/N)/(D )
						(D )/(A )	(A )/(N/A)	(A/A)/(N/N)	(N )/(A/N)	(N/A)/(D )	(N/N)/(N )
(D )/(A/A)	(A )/(N/N)	(A/N)/(A )	(N )/(D )	(N/A)/(N )	(N/N)/(N/A)
						(D )/(A/N)	(A/A)/(A )	(A/N)/(A/A)	(N )/(N )	(N/A)/(N/A)	(N/N)/(N/N)

In another embodiment, paired packet DTX reporting may be applied without network signaling assistance, which may end up with the same reporting status table as table 8. In this embodiment, single carrier transmission in the pairing may be blocked by a grouped DTX report. To avoid this blocking, transmission may be restricted as in the case of restricted transmission from the node-B, whereby data transmission may be allowed on one carrier in the pair.

In a third embodiment, conditional DTX reporting from NACK transitions is applied by transitioning some NACKs to DTX to merge less likely states. For example, if a NACK is detected in one carrier and if the number of NACKs in the other carriers is greater than two, a DTX is reported for that carrier. Otherwise, the state remains unchanged. The mapping relationship created is shown in table 11.

TABLE 11

The number of reported states is reduced from 80 to 47 as shown in table 12, which lists the pending states received by node-B420.

TABLE 12

A/A/A/A	A/D/A/A	A/N/A/A	D/A/D/D	D/D/D/N	N/A/A/D
						A/A/A/D	A/D/A/D	A/N/A/D	D/A/D/N	D/D/N/A	N/A/D/A
A/A/A/N	A/D/A/N	A/N/D/A	D/A/N/A	D/D/N/D	N/A/D/D
						A/A/D/A	A/D/D/A	A/N/D/D	D/A/N/D	D/N/A/A	N/D/A/A
A/A/D/D	A/D/D/D	D/A/A/A	D/D/A/A	D/N/A/D	N/D/A/D
						A/A/D/N	A/D/D/N	D/A/A/D	D/D/A/D	D/N/D/A	N/D/D/A
A/A/N/A	A/D/N/A	D/A/A/N	D/D/A/N	D/N/D/D	N/D/D/D
						A/A/N/D	A/D/N/D	D/A/D/A	D/D/D/A	N/A/A/A

The binary codeword specified in table 2 may be used to encode the states given in table 12 to generate a ten-bit HARQ-ACK message carried by the HS-SCCH. This process is performed by the following process: any mapping from 47 states to entries of the codeword table is identified and the encoding is then performed.

In another three carrier example, where one carrier is configured with MIMO, carrier C1, and carrier C2 are assumed to represent two carriers that do not perform MIMO, while carrier C3 is assumed to represent carriers that perform MIMO, grouped into a pair (C1/C2). The carriers performing MIMO may be processed without any further processing. The composite HARQ-ACK state is represented by (C1, C2)/C3. Table 13 shows possible combinations of HARQ-ACK states for three carriers (one of which is configured with MIMO), which have a total of 62.

Watch 13

(A/A)/A

(A/D)/D

(A/N)/NN

(D/D)/AN

(D/N)/NN

(N/D)/AN

(N/N)/NA

(A/A)/AA

(A/D)/N

(D/A)/A

(D/D)/N

(N/A)/A

(N/D)/D

(N/N)/NN

(A/A)/AN

(A/D)/NA

(D/A)/AA

(D/D)/NA

(N/A)/AA

(N/D)/N

(A/A)/D

(A/D)/NN

(D/A)/AN

(D/D)/NN

(N/A)/AN

(N/D)/NA

(A/A)/N

(A/N)/A

(D/A)/D

(D/N)/A

(N/A)/D

(N/D)/NN

(A/A)/NA

(A/N)/AA

(D/A)/N

(D/N)/AA

(N/A)/N

(N/N)/A

(A/A)/NN

(A/N)/AN

(D/A)/NA

(D/N)/AN

(N/A)/NA

(N/N)/AA

(A/D)/A

(A/N)/D

(D/A)/NN

(D/N)/D

(N/A)/NN

(N/N)/AN

(A/D)/AA

(A/N)/N

(D/D)/A

(D/N)/N

(N/D)/A

(N/N)/D

(A/D)/AN

(A/N)/NA

(D/D)/AA

(D/N)/NA

(N/D)/AA

(N/N)/N

Table 14 shows a combined reduction mapping table for three carriers (one of which is configured with MIMO). To optimize the codebook table, the same process according to table 7 (i.e., conditional packet DTX reporting according to network signaling) is applied to (C1/C2), which results in a composite mapping as shown in table 14. One bit of network signaling is used to indicate both modes of dual TX, indicating transmission on carrier C1 and carrier C2, and single TX, indicating transmission on one carrier of the pair.

TABLE 14

Table 15 shows the reported HARQ-ACK states for three carriers (one of which performs MIMO). The remaining pending status resulting from the reduction mapping is given in table 15, which is reported to node-B420.

Watch 15

(A/A)/A	(A/N)/NA	(N/A)/N
			(A/A)/AA	(A/N)/NN	(N/A)/NA
(A/A)/AN	(D/D)/A	(N/A)/NN
			(A/A)/D	(D/D)/AA	(N/N)/A
(A/A)/N	(D/D)/AN	(N/N)/AA
			(A/A)/NA	(D/D)/N	(N/N)/AN
(A/A)/NN	(D/D)/NA	(N/N)/D
			(A/N)/A	(D/D)/NN	(N/N)/N
(A/N)/AA	(N/A)/A	(N/N)/NA
			(A/N)/AN	(N/A)/AA	(N/N)/NN
(A/N)/D	(N/A)/AN
			(A/N)/N	(N/A)/D

Thus, the size of the codebook is reduced from 62 to 34. If it is desired to use an existing codebook from an existing coding scheme (e.g., the scheme used in the 3GPP specification), a reduced mapping for (C1/C2) may be performed according to Table 9, which results in a final reported state similar to that of Table 10. In the final stage, the 48 states are encoded into ten-bit codewords according to the channel coding table specified in table 2.

In a third example of four carriers (where MIMO is configured on two carriers), two of the four carriers may be configured with MIMO mode while the other two carriers are not configured with MIMO. For this case, there are a total of 9 x 49-1-440 possible combinations in HARQ-ACK. Assume that carrier C1 and carrier C2 are two carriers that do not MIMO. They are grouped into a pair and possible combinations of HARQ-ACK states associated with the pair are handled by the same reduced mapping operation as specified in table 4 based on input of node-B420 signaling. Since there are five pending states in table 4, the total number of composite HARQ-ACK states incorporating MIMO-enabled or non-MIMO enabled carriers may be reduced to 5 × 49-1 — 244 after the reduction. Thus, the size of the codebook is reduced from 440 to 244.

Knowing the number of carriers that are transmitting data is useful to minimize the loss due to DTX reporting of the packet. The node-B420 indicates the carrier activity to the WTRU410, which is described in more detail below. The WTRU410 detects the indication from the node-B420 and applies the appropriate codebook compression to the HARQ-ACK field in the corresponding HS-SCCH.

Carrier activity may be indicated, for example using HS-SCCH. For example, new data indicator bits may be reused. In another embodiment, the carrier activity information is provided by HS-SCCH type 1 at the location of the new data indicator bit. Alternatively, the HS-SCCH type 3 format of a single transport block is used for HS-DSCH transmission. Since the MIMO mode may not be configured when performing DTX reporting of a packet, some signaling bits for MIMO may be used for reporting carrier activity. The bits may include, for example, x_wipb1、x_pwipb2、x_ms3Or x_ccs7。

Alternatively, an HS-SCCH type 3 format for both transport blocks may be used, wherein a further information field for the secondary transport block may be used to send configuration information copied from the other carrier in the pair.

Examples

1. A method, the method comprising:

multiple carriers are assigned to a wireless transmit/receive unit (WTRU).

2. A method of hybrid automatic repeat request (HARQ) acknowledgement codebook optimization for multiple downlink carrier operation.

3. The method of embodiment 1, wherein the assignment is an explicit configuration signal.

4. The method of any preceding embodiment, further comprising transmitting feedback information on the first uplink physical control channel and the second uplink physical control channel.

5. The method of any preceding embodiment, wherein the first uplink physical control channel and the second uplink physical control channel are on different frequencies.

6. The method of any preceding embodiment, further comprising wherein the first uplink physical control channel and the second uplink physical control channel have different scrambling codes.

7. The method of any preceding embodiment, further comprising transmitting an acknowledgement/negative acknowledgement (ACK/NACK) and a Channel Quality Indicator (CQI) for two carriers on the first uplink physical control channel.

8. The method of any preceding embodiment, further comprising transmitting feedback for a further carrier on the second uplink physical control channel.

9. The method of any preceding embodiment, further comprising assigning an uplink scrambling code for each of a plurality of uplink physical control channels.

10. The method according to any one of the preceding embodiments, further comprising assigning a physical uplink control channel for each pair of carriers configured.

11. The method as in any one of the preceding embodiments, further comprising encoding a hybrid automatic repeat request (HARQ) ACK message and CQI using a current single carrier channel coding for a high speed dedicated physical control channel (HS-DPCCH) when MIMO is not configured.

12. The method as in any one of the preceding embodiments, further comprising using channel coding for HS-DPCCH in the presence of a secondary carrier as defined in third generation partnership project (3GPP) Technical Specification (TS) 25.212.

13. The method of any preceding embodiment, wherein each uplink physical control channel of the plurality of uplink physical control channels is configured with dual carrier channel coding.

14. The method as in any one of the preceding embodiments wherein the channelization code and the branch for the second HS-DPCCH are designed to minimize a cubic metric.

15. The method of any preceding embodiment, wherein multiple UL physical control channels are transmitted on the same carrier.

16. The method of any preceding embodiment, further comprising transmitting the first uplink physical control channel on an anchor carrier and transmitting a second uplink physical control channel on a secondary carrier.

17. The method as in any one of the preceding embodiments, wherein a pair of carriers associated with each uplink physical control channel is explicitly configured using Radio Resource Control (RRC) signaling.

18. The method of any preceding embodiment wherein the first and second carriers correspond to first adjacent frequencies of anchor downlink and primary carriers and the third and fourth carriers correspond to remaining secondary frequencies of the WTRU.

19. The method of any preceding embodiment, wherein the first and second carriers correspond to anchor downlink carriers and supplementary carriers and the third and fourth carriers correspond to secondary carriers and neighboring carriers.

20. The method of any preceding embodiment, wherein the first and second carriers correspond to two downlink anchor carriers and the third and fourth carriers correspond to a supplementary carrier.

21. The method of any preceding embodiment, wherein the first and second carriers correspond to anchor and secondary carriers associated with an uplink carrier that is transmitting a first physical uplink control channel, and the third and fourth carriers correspond to anchor and secondary carriers associated with an uplink carrier that is transmitting a second physical uplink control channel.

22. The method according to any of the preceding embodiments, wherein the HS-DPCCH is band-dependent.

23. The method as in any one of the preceding embodiments, wherein one HS-DPCCH is used for each frequency band.

24. The method of any preceding embodiment wherein the WTRU transmits up to four HARQ feedback and four CQI feedback in a four carrier multi-carrier system, wherein each of the HARQ feedback and the CQI feedback is carried by one of the four carriers.

25. The method as in any one of the preceding embodiments, wherein for each HARQ feedback combination there are multiple possible CQI feedback combinations.

26. The method as in any one of the preceding embodiments wherein the WTRU uses one or two HS-DPCCHs according to the feedback combination.

27. The method of any preceding embodiment wherein the WTRU signals an indication of which carrier is sending feedback to the network.

28. The method as in any one of the preceding embodiments wherein the WTRU transmits the indication using the HS-DPCCH channelization code number.

29. The method as in any one of the preceding embodiments, wherein the WTRU sends the indication along with the CQI feedback and the HARQ feedback in a frequency band.

30. The method according to any of the preceding embodiments, wherein the network blindly detects the content (text) of the carriers used for providing the CQI feedback and the HARQ feedback.

31. The method as in any one of the preceding embodiments, wherein a single HS-DPCCH channelization code is used to carry feedback information.

32. The method according to any of the preceding embodiments, further comprising transmitting HARQ feedback using an HS-DPCCH frame format, wherein the HS-DPCCH frame format carries only ACK/NACK feedback and does not carry any CQI reports.

33. The method as in any one of the preceding embodiments, further comprising multiplexing the CQI feedback and the HARQ feedback in the same HS-DPCCH code.

34. The method of any preceding embodiment, further comprising transmitting a plurality of CQI reports for a plurality of downlink carriers.

35. The method as in any one of the preceding embodiments, further comprising generating a composite CQI report from the plurality of CQI reports.

36. The method according to any of the preceding embodiments, further comprising transmitting one composite CQI report together with the HARQ feedback in HS-DPCCH.

37. The method as in any one of the preceding embodiments, further comprising transmitting the CQI for one carrier at a time in different subframes.

38. The method as in any one of the preceding embodiments, further comprising time multiplexing feedback information on two consecutive subframes.

39. The method as in any one of the preceding embodiments, wherein the CQI for each carrier may be reported once every four pairs of subframes.

40. The method of any preceding embodiment, wherein the CQI for each pair of carriers is reported once every two pairs of subframes.

41. The method as in any one of the preceding embodiments, further comprising time multiplexing the feedback information on the two carriers.

42. The method of any preceding embodiment, wherein the CQI for only one downlink carrier is reported in each of a plurality of subframes.

43. The method according to any of the preceding embodiments, wherein two downlink carriers are reported in each subframe.

44. The method according to any of the preceding embodiments, wherein HARQ feedback may also be reported for two downlink carriers in each slot.

45. The method of any preceding embodiment wherein the WTRU automatically determines when to transmit a CQI for each of a plurality of carriers.

46. The method of any preceding embodiment wherein the WTRU monitors the quality of all carriers and transmits a new CQI if the quality of one of the carriers changes by more than a predetermined amount.

47. The method according to any of the preceding embodiments, wherein the quality is based on a calculated CQI.

48. The method of any preceding embodiment wherein the WTRU transmits the CQI for the carrier that experiences the greatest change in quality when the WTRU determines that more than one carrier requires CQI updates.

49. The method as in any one of embodiments 44-46 wherein the WTRU transmits a CQI for a carrier that reflects the largest due to the use of an updated CQI.

50. The method as in any one of embodiments 43-48 wherein the WTRU includes carrier index information in the HS-DPCCH feedback.

51. The method according to any of the preceding embodiments, wherein a two-bit carrier index is transmitted together with the CQI feedback.

52. The method as in any one of the preceding embodiments, wherein the WTRU indicates a carrier index using a codeword reserved for HARQ feedback when HARQ feedback is not needed.

53. The method as in any one of embodiments 43-51 wherein the WTRU time multiplexes feedback over two consecutive frames.

54. The method according to any of the preceding embodiments, wherein the HARQ feedback is transmitted in the first two slots of each subframe, and the CQI feedback is spread over every two consecutive subframes.

55. The method according to any of the preceding embodiments, wherein two HS-DPCCH codes are used to transmit HARQ feedback and CQI feedback separately.

56. The method as in any one of the preceding embodiments, further comprising transmitting the jointly encoded HARQ feedback on the first HS-DPCCH.

57. The method as in any one of the preceding embodiments, further comprising transmitting the plurality of CQI blocks via a second HS-DPCCH in a full subframe.

58. The method of any preceding embodiment, further comprising configuring a different scrambling code for each of a plurality of HS-DPCCHs.

59. The method as in any one of the preceding embodiments, further comprising providing feedback for multiple carriers on an HS-DPCCH.

60. The method of embodiment 2, further comprising composing the reply message.

61. The method according to any of the preceding embodiments, wherein the composite acknowledgement message is represented by HARQ-ACK states consisting of letters A, N, or D, separated by a delimiter "/", to indicate the HARQ state of the carrier, wherein 'a' means 'ACK', 'N' means 'NACK', and 'D' means 'no transmission' (DTX).

62. The method of any preceding embodiment, wherein a set of carriers or data streams are grouped and, if DTX is detected from any one of the carriers or any one of the data streams, DTX is announced on all other carriers or streams regardless of HARQ-ACK status of the other carriers or streams in the group.

63. The method of any preceding embodiment, wherein in the event that a certain number of DTX states are detected from any one of the carriers or any one of the data streams, DTX is announced on all other carriers or streams regardless of HARQ-ACK states on the other carriers or streams in the packet.

64. The method according to any of the preceding embodiments, wherein some HARQ states are mapped differently to other states according to signaling received from the network.

65. The method as in any one of the preceding embodiments, wherein HARQ states are mapped differently on a per Transmission Time Interval (TTI) basis.

66. The method as in any one of the preceding embodiments, wherein the signaling is an indication of a number of transport blocks being transmitted in a current TTI or group of TTIs.

67. The method of any preceding embodiment wherein a group of carriers are grouped and data transmission is not allowed at the node B transmitter on a per TTI or group of TTIs basis on all carriers in the set at the same time.

68. The method according to any one of the preceding embodiments, wherein the HS-SCCH is sent if other carriers in the set are transmitting.

69. The method of any preceding embodiment, wherein a set of carriers or data streams are grouped and, in the event that one NACK or a certain number of NACKs is detected from any one of the carriers or any one of the data streams, then NACKs are announced on all other carriers or streams regardless of HARQ-ACK status on all other carriers or streams in the group.

70. The method of any preceding embodiment, wherein if a NACK is detected from any one of the carriers or any one of the data streams, a NACK is announced on all other carriers or data streams having a detected ACK status.

71. The method of any preceding embodiment, wherein in the event that a NACK is detected on a carrier or stream, the NACK is converted to a DTX for reporting.

72. The method of any preceding embodiment, wherein the condition for transitioning to DTX comprises any combination of the following conditions: the number of DTX states in all carriers or streams is greater than a certain value, the number of NACK states in all carriers or streams is greater than a certain value, and/or the number of ACK states in all carriers or streams is less than a certain or configured value.

73. The method as in any one of the preceding embodiments, wherein in the event that an ACK is detected on a carrier or stream, the ACK is converted to a NACK for reporting.

74. The method of any preceding embodiment, wherein in the event that there is an arbitrary DTX in a pair and network signaling indicates dual carrier transmission on the pair, the DTX is reported on both carriers.

75. The method of any preceding embodiment, wherein in the event that there is any DTX in a pair and network signaling indicates a single carrier transmission on the pair, repeating the "true" state from the other carriers.

76. The method according to any of the preceding embodiments, wherein the HARQ-ACK state for a composite report for all carriers is obtained by mapping a mapping to each pair independently and concatenating them.

77. The method according to any of the preceding embodiments, applying paired DTX packet reporting without using network signaling.

78. The method as in any one of the preceding embodiments, further comprising restricting transmissions.

79. The method of any of the preceding embodiments, wherein less likely states are merged.

80. The method according to any of the preceding embodiments, wherein some NACKs are converted to DTX.

81. The method of any preceding embodiment, wherein in the event that a NACK is detected on one carrier, and if the number of NACKs in the other carriers is greater than 2, reporting a DTX for that carrier.

82. The method as in any one of the preceding embodiments, further comprising indicating carrier activity.

83. A method as in any preceding embodiment further comprising detecting the transmitted indication and applying appropriate codebook compression to the HARQ-ACK field in the corresponding HS-SCCH.

84. The method according to any one of the preceding embodiments, further comprising indicating carrier activity information on HS-SCCH type 1.

85. The method as in any one of the preceding embodiments, further comprising indicating carrier activity information in new data indicator bits.

86. The method as in any one of the preceding embodiments, further comprising reporting carrier activity using signaling bits for MIMO.

87. The method according to any one of the preceding embodiments, further comprising using a further information field to indicate carrier activity information according to the HS-SCCH type 3 format.

88. The method of any preceding embodiment, wherein the receiver displays any combination of the following states: the receiver correctly receives the HS-SCCH, and the data packets associated with the HS-PDSCH and the ACK, the receiver correctly receives the control information from the HS-SCCH, but detects an error and a NACK in the data packets, and/or the receiver fails to detect the HS-SCCH matching the ID assigned to the current wireless transmit/receive unit (WTRU) at the current TTI and declares DTX.

89. A wireless transmit/receive unit (WTRU) configured to perform the method of any of the preceding embodiments.

90. An Integrated Circuit (IC) configured to perform the method of any of embodiments 1-88.

91. A node-B configured to perform the method of any of embodiments 1-88.

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 (17)

1. A wireless transmit/receive unit (WTRU), comprising:

a receiver configured to receive signals on a plurality of downlink carriers;

circuitry configured to determine feedback for each of the plurality of downlink carriers based on the received signals; and

a plurality of antennas configured to transmit feedback for at least one of the plurality of downlink carriers on a first physical channel and to transmit feedback for another one of the plurality of downlink carriers on a second physical channel.

2. The WTRU of claim 1 wherein the first physical channel is sent on a first carrier and the second physical channel is sent on a second carrier.

3. The WTRU of claim 2, wherein the first physical channel and the second physical channel use the same channelization code and in-phase/quadrature (I/Q) branch.

4. The WTRU of claim 1 wherein the first physical channel has a different channelization code than the second physical channel.

5. The WTRU of claim 1 further comprising circuitry configured to autonomously transmit the first physical channel and the second physical channel on a single carrier with deactivation of a secondary uplink carrier.

6. The WTRU of claim 1 further comprising a state reduction device configured to map actual hybrid automatic repeat request-acknowledgement (HARQ-ACK) states to a smaller set of reported HARQ-ACK states.

7. A wireless transmit/receive unit (WTRU), comprising:

a receiver configured to receive signals on a plurality of downlink carriers;

circuitry configured to generate feedback based on the received signal for transmission on a first high speed dedicated physical control channel (HS-DPCCH1) and a second high speed dedicated physical control channel (HS-DPCCH) HS-DPCCH 2; and

an antenna configured to transmit the HS-DPCCH1 and the HS-DPCCH2, wherein the HS-DPCCH1 and the HS-DPCCH2 are time-multiplexed and transmitted on a single carrier.

8. The WTRU of claim 7, further comprising a transmitter configured to transmit at least two Channel Quality Indicators (CQIs) over two consecutive subframes.

9. The WTRU of claim 7 wherein the HS-DPCCH1 and the HS-DPCCH2 are transmitted using a spreading factor of 128.

10. The WTRU of claim 7 wherein a first slot and a second slot of a subframe are used to provide hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback for up to four downlink carriers.

11. The WTRU of claim 7, further comprising circuitry configured to autonomously transmit the first physical channel and the second physical channel on different carriers on a condition that a secondary uplink carrier is activated.

12. The WTRU as in claim 7 further comprising a state reduction device configured to map actual HARQ-ACK states to a smaller set of reported HARQ-ACK states.

13. A method implemented in a wireless transmit/receive unit (WTRU), the method comprising:

receiving signals on a plurality of downlink carriers;

generating feedback for each of the plurality of downlink carriers based on the received signals; and

transmitting feedback for at least one of the plurality of downlink carriers on a first physical channel via a plurality of antennas and transmitting feedback for another one of the plurality of downlink carriers on a second physical channel.

14. The method of claim 13, wherein the first physical channel is transmitted on a first carrier and the second physical channel is transmitted on a second carrier.

15. The method of claim 14, wherein the first physical channel and the second physical channel use a same channelization code and in-phase/quadrature (I/Q) branch.

16. The method of claim 13, wherein the first physical channel has a different channelization code than the second physical channel.

17. The method of claim 13, further comprising autonomously transmitting the first physical channel and the second physical channel on a single carrier with deactivation of a secondary uplink carrier.