Indexing resources for transmission of acknowledgement signals in multi-cell TDD communication systems

Abstract

Disclosed is a method for transmitting acknowledgement information by a user equipment in a wireless communication system, including receiving information indicating a resource for transmission of the acknowledgement information on a downlink control channel, determining a resource for transmitting the acknowledgement information based on the received information, and transmitting the acknowledgement information on the determined resource.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving, from a base station, scheduling information for downlink data on a downlink control channel, the scheduling information including a hybrid automatic repeat request (HARQ) resource indicator for a physical uplink control channel (PUCCH), wherein the HARQ resource indicator indicates a value for a PUCCH-resource index among a plurality of values for PUCCH resource indices associated with transmission of acknowledgement information; receiving, from the base station, the downlink data on a downlink shared channel; determining a PUCCH resource for transmitting the acknowledgement information corresponding to the downlink data based on the received HARQ resource indicator, a total number of control channel elements (CCEs), and an index of a first CCE for the downlink control channel; and transmitting, to the base station, the acknowledgement information on the determined PUCCH resource.

2. The method of claim 1, wherein the PUCCH resource is further determined based on radio resource control (RRC) signaling for PUCCH resources.

3. A method performed by a base station in a wireless communication system, the method comprising: transmitting, to a user equipment (UE), scheduling information for downlink data on a downlink control channel, the scheduling information including a hybrid automatic repeat request (HARQ) resource indicator for a physical uplink control channel (PUCCH), wherein the HARQ resource indicator indicates a value for a PUCCH-resource index among a plurality of values for PUCCH resource indices associated with transmission of acknowledgement information; transmitting, to the UE, the downlink data on a downlink shared channel; and receiving, from the UE, the acknowledgement information on a PUCCH resource, wherein the PUCCH resource depends on the HARQ resource indicator, a total number of control channel elements (CCEs), and an index of a first CCE for the downlink control channel.

4. The method of claim 3, wherein the PUCCH resource is further determined according to radio resource control (RRC) signaling for PUCCH resources.

5. A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a base station, scheduling information for downlink data on a downlink control channel, the scheduling information including a hybrid automatic repeat request (HARQ) resource indicator for a physical uplink control channel (PUCCH), wherein the HARQ resource indicator indicates a value for a PUCCH-resource index among a plurality of values for PUCCH resource indices associated with transmission of acknowledgement information, receive, from the base station, the downlink data on a downlink shared channel, determine a PUCCH resource for transmitting the acknowledgement information corresponding to the data based on the received HARQ resource indicator, a total number of control channel elements (CCEs), and an index of a first CCE for the downlink control channel, and transmit, to the base station, the acknowledgement information on the determined PUCCH resource.

6. The UE of claim 5, wherein the PUCCH resource is further determined based on radio resource control (RRC) signaling for PUCCH resources.

7. A base station in a wireless communication system, the base station comprising: a transceiver; and a controller coupled with the transceiver and configured to: transmit, to a user equipment (UE), scheduling information for downlink data on a downlink control channel, the scheduling information including a hybrid automatic repeat request (HARQ) resource indicator for a physical uplink control channel (PUCCH), wherein the HARQ resource indicator indicates a value for a PUCCH-resource index among a plurality of values for PUCCH resource indices associated with transmission of acknowledgement information, transmit, to the UE, the downlink data on a downlink shared channel, and receive, from the UE, the acknowledgement information on a PUCCH resource, wherein the PUCCH resource depends on the HARQ resource indicator, a total number of control channel elements (CCEs), and an index of a first CCE for the downlink control channel.

8. The base station of claim 7, wherein the PUCCH resource is further determined according to radio resource control (RRC) signaling for PUCCH resources.

9. The method of claim 1, wherein the HARQ resource indicator includes at least one bit having a value that corresponds to the value for the PUCCH resource index.

10. The method of claim 3, wherein the HARQ resource indicator includes at least one bit having a value that corresponds to the value for the PUCCH resource index.

11. The UE of claim 5, wherein the HARQ resource indicator includes at least one bit having a value that corresponds to the value for the PUCCH resource index.

12. The base station of 7, wherein the HARQ resource indicator includes at least one bit having a value that corresponds to the value for the PUCCH resource index.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other aspects, features, and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a diagram illustrating a conventional PUCCH sub-frame structure for an HARQ-ACK signal transmission;

(3) FIG. 2 is a diagram illustrating an HARQ-ACK signal transmission in a sub-frame slot for a PUCCH structure as illustrated in FIG. 1;

(4) FIG. 3 is a block diagram illustrating a transmitter for a PUCCH structure as illustrated in FIG. 1;

(5) FIG. 4 is a block diagram illustrating a receiver for a PUCCH structure as illustrated in FIG. 1;

(6) FIG. 5 is a diagram illustrating a transmission of a DL SA using CCEs in a PDCCH;

(7) FIG. 6 is a diagram illustrating block interleaving of PUCCH resources assuming a Time Division Duplex system with 3 DL sub-frames in a bundling window;

(8) FIG. 7 is a diagram illustrating resource allocation in a UL CC for HARQ-ACK signal transmissions corresponding to DL SAs received in 3 DL CCs;

(9) FIG. 8 is a diagram illustrating a conventional PUCCH structure in one sub-frame slot using DFT Spread OFDM for the HARQ-ACK signal transmission;

(10) FIG. 9 is a block diagram illustrating a transmitter for a PUCCH structure as illustrated in FIG. 8;

(11) FIG. 10 is a block diagram illustrating a receiver for a PUCCH structure as illustrated in FIG. 8;

(12) FIG. 11 is a diagram illustrating a transmission of 3 DL SAs in a DL PCC and a mapping of the respective 3 resources available for a transmission of an HARQ-ACK signal, according to an embodiment of the present invention;

(13) FIG. 12 is a diagram illustrating a restriction that UEs having a same DL PCC are activated (and deactivated) DL SCCs in a same order, according to an embodiment of the present invention;

(14) FIG. 13 is a diagram illustrating an ordering of activation and deactivation for 5 DL CCs depending on the DL CC used for the transmission of the respective DL SAs, according to an embodiment of the present invention;

(15) FIG. 14 is a diagram illustrating use of a TPC IE in a first ordered DL SA, as determined by a DAI IE value, to provide a TPC command for an HARQ-ACK signal transmission and use of a TPC IE in remaining DL SAs to provide an index for a respective resource for the HARQ-ACK signal transmission, according to an embodiment of the present invention;

(16) FIG. 15 is a block diagram illustrating a transmitter for a PUCCH structure where a resource for an HARQ-ACK signal transmission is indexed by a TPC IE value in a DL SA, other than a first ordered DL SA, as determined from a value of a DAI IE, according to an embodiment of the present invention;

(17) FIG. 16 is a block diagram illustrating a receiver for a PUCCH structure where a resource for an HARQ-ACK signal reception is indexed by a TPC IE value in a DL SA, other than a first ordered DL SA, as determined from a value of a DAI IE, according to an embodiment of the present invention; and

(18) FIG. 17 is a diagram illustrating a resource mapping for an HARQ-ACK signal transmission for 2 DL CCs, each transmitting its own DL SA, using a DL CC specific offset, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(19) Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.

(20) Additionally, although the present invention is described for a communication system using DFT-S-OFDM or Single-Carrier Frequency Division Multiple Access (SC-FDMA) transmission, it also generally applicable to other Frequency Division Multiplexing (FDM) transmissions including OFDM.

(21) Methods and apparatuses are described for a UE to determine the PUCCH resource for HARQ-ACK signal transmission, in response to multiple DL SA receptions in multiple DL CCs or in multiple DL sub-frames.

(22) In accordance with an embodiment of the present invention, PUCCH resources are indexed for HARQ-ACK signal transmission in a UL PCC (herein referred to as HARQ-ACK resources). The HARQ-ACK resources may be RRC-configured to a UE (for example, using the PUCCH structure as illustrated in FIG. 8) or may be dynamically determined by a UE using the indexes of the CCEs for the respective DL SAs (for example, using the PUCCH structure as illustrated in FIG. 1).

(23) Herein, the HARQ-ACK signal transmission in the PUCCH is assumed to be based on the following two principles:

(24) 1. A single UE-specific UL CC (UL PCC) is RRC-configured for the HARQ-ACK transmission in the PUCCH for a UE configured multiple DL CCs.

(25) 2. For a UE configured single UL/DL carrier-pair operation in FDD and receiving a DL SA in a single DL sub-frame in the DL PCC in TDD, the HARQ-ACK resource is implicitly derived from the CCEs of the respective DL SA, as it was previously described.

(26) RRC-configured CCs can be activated or deactivated, for example by medium access control signaling. Herein, activation of a DL (or UL) CC means that the UE can receive PDSCH (or transmit PUSCH) in that CC. Similarly, the reverse applies for deactivation of a DL (or UL) CC. To maintain communication, one DL CC remains activated and is referred to as a DL Primary CC (DL PCC). The remaining DL CCs are referred to as DL Secondary CCs (DL SCCs). The DL PCC is assumed to be linked to the UL PCC and both are UE-specific.

(27) For HARQ-ACK resource mapping in the UL PCC, the following two cases exist for a UE having communication in multiple DL CCs:

(28) 1. All DL SAs scheduling PDSCH in the multiple DL CCs are transmitted in the DL PCC.

(29) For example, in heterogeneous network operation with 2 DL CCs and 2 UL CCs.

(30) 2. Some DL SAs scheduling PDSCH in multiple DL CCs are not transmitted in the DL PCC.

(31) For example, parallelizing the nominal operation with a single UL/DL carrier pair.

(32) Using a PUCCH structure as illustrated in FIG. 1, in accordance with an embodiment of the present invention, HARQ-ACK resource mapping depends on whether the first or the second of the previous two cases applies. For the first case, HARQ-ACK resource mapping rules used for a FDD system with a single DL/UL CC pair are generalized and expanded. For the second case, the HARQ-ACK resource mapping rules used for a TDD system with a single UL/DL CC pair are generalized and expanded, subject to additional conditions.

(33) For the first case (all DL SAs are transmitted in the DL PCC), assuming that a UE receives M DL SAs for respective PDSCH receptions in M DL CCs, and denoting the first CCE for each of the M DL SAs as n.sub.CCE(m), n=0, 1, . . . , M−1, the resource available for the HARQ-ACK signal transmission in response to PDSCH reception in DL CC m is determined as shown in Equation (1).
n.sub.PUCCH(m)=n.sub.CCE(m)+N.sub.PUCCH, m=0,1, . . . ,M−1  (1)

(34) FIG. 11 illustrates a transmission of three DL SAs in a DL PCC of a UE and mapping three respective HARQ-ACK resources.

(35) Referring to FIG. 11, DL SA 1 1110 includes 2 CCEs 1111 and 1112, where the first CCE 1111 maps to a first HARQ-ACK resource (RSRC) 1140. DL SA 2 1120 includes 4 CCEs 1121, 1122, 1123, and 1124, where the first CCE 1121 maps to a second HARQ-ACK resource (RSRC) 1150. DL SA 3 1130 includes 2 CCEs 1131 and 1132, where the first CCE 1131 maps to a third HARQ-ACK resource (RSRC) 1160.

(36) For the second case (some DL SAs to a UE are not transmitted in the DL PCC), there is a restriction that UEs having the same DL PCC are activated (and deactivated) DL SCCs in the same order which is configured by RRC signaling.

(37) FIG. 12 is a diagram illustrating a restriction that UEs having a same DL PCC are activated (and deactivated) DL SCCs in a same order, according to an embodiment of the present invention.

(38) Referring to FIG. 12, UEs with DL CC2 1210 as a DL PCC are activated (and deactivated) DL SCCs in the same order, for example, starting with DL CC3 1220, and then continuing with DL CC4 1230, DL CC5 1240, and DL CC1 1250. UEs having DL CC 2 as DL PCC can have a different number of activated DL SCCs. Then, as a UE decodes the PCFICH in its activated DL CCs, it can identify the corresponding reserved HARQ-ACK resources from the PDCCH size. This restriction applies only for DL SCCs having PDCCH transmissions.

(39) FIG. 13 is a diagram illustrating an ordering of activation and deactivation for 5 DL CCs depending on the DL CC used for the transmission of the respective DL SAs, according to an embodiment of the present invention.

(40) Referring to FIG. 13, for a reference UE, DL CC2 (DL PCC) 1310 conveys DL SAs for DL CC2 1310A, DL CC3 1310B, and DL CC4 1310C. DL CC5 1320 conveys DL SAs for DL CC5 1320A. DL CC1 1330 conveys DL SAs for DL CC1 1330A. Because scheduling in DL CC3 and DL CC4 is through DL SAs transmitted in DL CC2 (for example, an index in the DL SA can indicate the DL CC), DL CC3 and DL CC4 can be activated (and deactivated) in any order. However, this is not the case for DL CC5 and DL CC1, which are activated (and deactivated) in the same order for all UEs having DL CC2 as their DL PCC. Moreover, the HARQ-ACK signal transmissions in response to DL SA receptions in DL CC5 and DL CC1 is not in the UL CC(s) linked to these DL CCs, but are in the UL PCC (which linked to the DL PCC assumed to be DL CC2).

(41) HARQ-ACK resource mapping will now be described below, assuming the previous restriction and considering for simplicity DL CCs of the same BW.

(42) Herein, M is the number of activated DL SCCs for a UE with DL SA transmissions to that UE, m=0, 1, . . . , M−1 is the index of the DL SCC in the set of M activated DL CCs, N.sub.p is the number of CCEs for a PCFICH value of p (where N.sub.0=0), and n.sub.CCE(m) is the first CCE in the DL SA scheduling PDSCH in DL SCC m.

(43) The UE first selects a value p ∈ {0, 1, 2, 3} that provides N.sub.p≤n.sub.CCE(m)<N.sub.p−1 and uses Equation (2) as the HARQ-ACK resource corresponding to PDSCH in DL SCC m.
n.sub.PUCCH(m)=(M−m−1)×N.sub.p+m×N.sub.p+1+n.sub.CCE(m)+N.sub.PUCCH, m=0, . . . ,M−1  (2)

(44) For DL SAs transmitted in the DL PCC, the HARQ-ACK resource mapping is as described in Equation (1).

(45) For M=4 activated DL SCCs with DL SA transmission to a UE, with each DL SCC having maximum PDCCH size of 3 OFDM symbols, N.sub.RB.sup.DL=100 PRBs, N.sub.sc.sup.RB=12 REs, and 36 REs per CCE, the maximum number of CCEs in a PDCCH is 87 and the HARQ-ACK resource indexing corresponding to PDSCH reception in DL SCC m=0, 1, . . . , M−1 is given in Table 2.

(46) TABLE-US-00002 TABLE 2 HARQ-ACK resource in DL SCC.sub.m n.sub.CCE < 22 22 ≤ n.sub.CCE < 55 55 ≤ n.sub.CCE < 88 m = 0 n.sub.PUCCH.sup.(1) = n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 66 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 154 + n.sub.CCE + N.sub.PUCCH.sup.(1) m = 1 n.sub.PUCCH.sup.(1) = 22 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 88 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 187 + n.sub.CCE + N.sub.PUCCH.sup.(1) m = 2 n.sub.PUCCH.sup.(1) = 44 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 121 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 220 + n.sub.CCE + N.sub.PUCCH.sup.(1) m = 3 n.sub.PUCCH.sup.(1) = 66 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 154 + n.sub.CCE + N.sub.PUCCH.sup.(1) n.sub.PUCCH.sup.(1) = 253 + n.sub.CCE + N.sub.PUCCH.sup.(1)

(47) The previous HARQ-ACK resource mapping for multiple DL CCs follows the principles of HARQ-ACK resource mapping in TDD systems with a single DL/UL carrier. However, as no HARQ-ACK resource compression is used, the maximum number of HARQ-ACK resources in the UL PCC can be very large. For example, using Table 2 for the previous setup, the maximum HARQ-ACK resources in the UL PCC for M=5 DL CCs can be computed as n.sub.PUCCH=253+n.sub.CCE+N.sub.PUCCH. Neglecting N.sub.PUCCH as it is only an offset, and assuming the maximum value of n.sub.CCE=87 for N.sub.RB.sup.DL=100 PRBs, the maximum number of HARQ-ACK resources in the UL PCC is 253+87=340. Assuming a maximum multiplexing capacity of 18 HARQ-ACK channels per PRB, about 19 PRBs are used to accommodate HARQ-ACK transmissions in the PUCCH of the UL PCC. This represents 19% of the total UL PCC resources. Moreover, as the DL PCC is not considered to participate in the HARQ-ACK resource mapping for DL SCCs having DL SA transmission (for example, the DL PCC may also support UEs configured with a single DL/UL CC pair), NodeB scheduler restrictions are used to avoid collisions of HARQ-ACK resources.

(48) To reduce the HARQ-ACK resources required to support communication over multiple DL CCs (for the second of the previous cases), in accordance with an embodiment of the present invention, for DL SAs scheduling PDSCH transmissions in DL SCCs, the NodeB scheduler can prioritize the placement of the first CCE to be within the first 22 CCEs (for the setup in Table 2). As the number of UEs scheduled in multiple DL CCs per sub-frame is typically small, the impact of this prioritization on the overall CCE availability is minor. Further, assuming that the CCEs are divided into CCEs that exist only in a UE-Common Search Space (UE-CSS) and CCEs that exist in a UE-Dedicated Search Space (UE-DSS), CCEs corresponding to the UE-CSS in DL SCCs can be omitted from the calculation of n.sub.CCE. Then, a maximum of about 88+22=110 HARQ-ACK resources will be used and, with 18 HARQ-ACK channels per PRB, about 6 PRBs in the UL PCC suffice. This represents about 6% maximum overhead to support HARQ-ACK transmissions, for all UEs. Such an overhead is tolerable and comparable to the maximum overhead of about 5 PRBs when UEs are configured only a single DL/UL CC pair.

(49) When HARQ-ACK resources (for the second of the previous cases) are configured by RRC signaling to a UE having communication over multiple DL CCs, additional HARQ-ACK resource overhead occurs due to the provision for the maximum HARQ-ACK resources for all UEs configured multiple DL CCs, regardless of whether these UEs are scheduled in a sub-frame. In peak conditions for DL CA support, the overhead due to HARQ-ACK resource allocation by RRC signaling may increase significantly while only modest increases can occur with dynamic HARQ-ACK resource allocation. HARQ-ACK resource sharing among multiple UEs can alleviate the increased overhead with HARQ-ACK resource allocation through RRC signaling, but such sharing imposes NodeB scheduler restrictions, as UEs sharing the same HARQ-ACK resource cannot have a DL SA in the same sub-frame.

(50) In accordance with another embodiment of the present invention HARQ-ACK resource compression is enabled. For example, HARQ-ACK overhead reduction may be achieved through NodeB scheduler restrictions by placing the first CCE of the respective DL SAs for DL SCCs in the first 22 CCEs (for the previous example). The scheduler will also then ensure that no DL SA in the DL PCC has a first CCE given as n.sub.CCE,1=22.Math.m+n.sub.CCE(m), m=0, . . . , M−1.

(51) Alternatively, the same resource mapping for all DL CCs can be used for the HARQ-ACK signal transmission in the UL PCC and n.sub.PUCCH(m)=n.sub.CCE(m)+N.sub.PUCCH, m=0, 1, . . . , M−1. Thereafter, the scheduler then ensures that n.sub.CCE(m), m=0, 1, . . . , M−1 is different among all DL CCs where a UE receives DL SA.

(52) To avoid having such constraints on the NodeB scheduler, an offset for the HARQ-ACK resource can be provided by the respective DL SA. The corresponding Information Element (IE) in the DL SA will be referred to as HARQ-ACK Resource Index (HRI) IE. Denoting the HRI IE value for DL SCC m as HRI (m), the HARQ-ACK resource corresponding to PDSCH in DL SCC m is obtained as
n.sub.PUCCH(m)=(M−m−1)×N.sub.p+m×N.sub.p+1+n.sub.CCE+N.sub.PUCCH+HRI(m), m=0, . . . ,M−1  (3)

(53) For example, assuming that HRI IE consists of 2 bits, its interpretation can be as in Table 3.

(54) TABLE-US-00003 TABLE 3 Mapping the HRI to an HARQ-ACK Resource Offset Value. HARQ-ACK Resource Index Field Offset Value 00 0 01 −1 10 1 11 2

(55) The HRI IE can also be used to avoid having the constraint that the first CCE the NodeB scheduler uses to transmit DL SAs in DL SCCs is within the first 22 CCEs (with or without accounting for CCEs allocated to the UE-CSS), that is n.sub.CCE(m)<22, m=0, . . . , M−1. Instead, the CCE index associated with the HARQ-ACK resource can be defined using the modulo operation with respect to a maximum CCE index value, N.sub.CCE.sup.max, and n.sub.PUCCH(m) as shown in Equation (4).
n.sub.PUCCH(m)=((M−m−1)×N.sub.p+m×N.sub.p+1+n.sub.CCE(m))mod(N.sub.CCE.sup.max)+N.sub.PUCCH+HRI(m), m=0, . . . ,M−1  (4)

(56) The value of N.sub.CCE.sup.max can be either signaled by the NodeB (RRC signaling or broadcast signaling) or be predefined. The modulo operation between two integers, x,y with y>0, is defined as x mod(y)=x−n.Math.y, where n=└x/y┘.

(57) In general, the HARQ-ACK resource corresponding to the PDSCH in DL CC m can be determined as a function of the first CCE used for the respective DL SA and the value of the HRI IE as shown in Equation (5).
n.sub.PUCCH(m)=ƒ(n.sub.CCE(m),HRI(m)), m=0,1, . . . ,M−1  (5)

(58) For example, the HARQ-ACK resource in response to DL SA reception in DL CC m can be determined as shown in Equation (6).
n.sub.PUCCH(m)=n.sub.CCE(m)+HRI(m)+N.sub.PUCCH, m=0,1, . . . ,M−1  (6)

(59) To further alleviate HARQ-ACK resource collisions, a DL CC specific offset N.sub.HARQ-ACK(m), m=0, 1, . . . , M−1 can be introduced, for example by RRC signaling, and n.sub.PUCCH(m) as shown in Equation (7).
n.sub.PUCCH(m)=n.sub.CCE(m)+HRI(m)+(m)+N.sub.PUCCH, m=0,1, . . . ,M−1  (7)

(60) Similarly, for the HARQ-ACK resource indexing in Equation (4), n.sub.PUCCH(m) can be determined, as shown in Equation (8).
n.sub.PUCCH(m)=((M−m−1)×N.sub.p+m×N.sub.p+1+n.sub.CCE(m))mod(N.sub.CCE.sup.max)+N.sub.PUCCH+HRI(m)+(m), m=0, . . . ,M−1  (8)

(61) The addition of an explicit HRI IE in the DL SAs can be avoided if an existing IE can be interpreted as providing the HRI. Assuming that DL SAs include a Downlink Assignment Index (DAI) IE that provides a count for the DL SA number, the DL SAs can be ordered.

(62) For example, assuming that a UE can receive DL SAs in DL CC1, DL CC2, DL CC3, and DL CC4 and that the NodeB transmits DL SAs to the UE in DL CC1, DL CC2, and DL CC4, the DAI IE in the DL SAs can have a value of 1 for DL CC2, a value of 2 for DL CC4, and a value of 3 for DL CC1. Accordingly, the UE identifies that the DL SA in DL CC2 is ordered first, the DL SA in DL CC4 is ordered second, and the DL SA in DL CC1 is ordered third. In a similar manner, for a TDD system with a single or multiple CCs and, for example, 4 DL sub-frames in the bundling window, the DAI IE can indicate whether the DL SA the UE receives in a sub-frame is the first, second, third, or fourth transmitted DL SA for the given CC.

(63) DL SAs are also assumed to include a Transmission Power Control (TPC) IE providing TPC commands in order for the UE to adjust the HARQ-ACK signal transmission power. It is assumed herein that all DL SAs include the TPC IE. However, because the HARQ-ACK signal transmission is only in the UL PCC, a single TPC command can suffice. In accordance with an embodiment of the present invention, a TPC command is provided by the TPC IE in the first DL SA, as determined by the DAI IE value. The TPC IEs in the remaining DL SAs can be used as HRI IEs.

(64) FIG. 14 illustrates a principle of identifying and using the bits of an IE in the DL SAs to index the resources for the HARQ-ACK signal transmission according to an embodiment of the present invention. Although FIG. 14 considers the TPC IE, an explicit HRI IE may be used instead.

(65) Referring to FIG. 14, a TPC IE in a first ordered DL SA 1410 (as determined by the DAI IE value) provides a TPC command for a HARQ-ACK signal transmission 1420 in response to reception of DL SAs. Each TPC IE in the remaining DL SA2 1430 through DL SA K 1450 is used as an index for HARQ-ACK resources 1440 through 1460, respectively.

(66) Although dynamically indexed HARQ-ACK resources are considered, the HRI functionality is independent of how the HARQ-ACK resource is determined and serves to further index the HARQ-ACK resources in order to avoid collisions when resource compression is applied to the HARQ-ACK resource mapping. Moreover, the HRI functionality is applicable to either a PUCCH structure as illustrated in FIG. 1 or a PUCCH structure as illustrated in FIG. 8 and to further indexing either dynamically determined or RRC-configured HARQ-ACK resources.

(67) If the first DL SA (with DAI=1) is missed by the UE, the TPC command for the HARQ-ACK transmission is missed and the UE does not perform a respective power adjustment. However, this is not expected to have a noticeable impact on the overall system operation as it is a low probability event, as UEs with DL CA have good link quality and DL SAs are unlikely to be missed, and the TPC adjustment is typically small. It is noted that if only the DL SA with DAI=1 is received by the UE (either in the DL PCC for FDD or in the first sub-frame of the DL PCC for TDD), the HARQ-ACK resource is implicitly derived from the CCEs of the respective DL SA (second principle for the HARQ-ACK signal transmission assumed by the invention).

(68) FIG. 15 is a block diagram illustrating a transmitter for a HARQ-ACK signal in a PUCCH where a resource for the HARQ-ACK signal transmission (HARQ-ACK resource) is indexed by a TPC IE value in a DL SA, other than a first ordered DL SA, as determined from a value of a DAI IE, according to an embodiment of the present invention. In FIG. 15, the main components are the same as those illustrated in FIG. 3 and described above, with the exception that the HARQ-ACK resource depends on an offset specified by a HRI value controller 1510 for mapping the TPC IE (or of the HRI IE) value, which the UE obtains from the respective DL SAs (with DAI IE value larger than one in the DL PCC) and uses to derive the HARQ-ACK resource. The HARQ-ACK resource includes the CS which is applied by the CS mapper 1520 and the PRB which is determined by the PRB selection controller 1530 (and also the OCC—not shown for simplicity). The transmitter structure as illustrated in FIG. 9 may be modified in the same manner.

(69) FIG. 16 is a block diagram illustrating a receiver for a HARQ-ACK signal in a PUCCH where a resource for the HARQ-ACK signal reception (HARQ-ACK resource) is indexed by a TPC IE value in a DL SA, other than a first ordered DL SA, as determined from a value of a DAI IE, according to an embodiment of the present invention. In FIG. 16, the main components are the same as those illustrated in FIG. 4 and described above, with the exception that the HARQ-ACK resource depends on the offset specified by the HRI value controller 1610 for the mapping of the TPC IE (or of the HRI IE) value, which the NodeB included in the respective DL SA. The resource includes the CS which is applied by the CS demapper 1630 and the PRB which is determined by PRB selection controller 1620 (and also the OCC—not shown for simplicity). The receiver structure as illustrated in FIG. 10 may also modified in the same manner.

(70) FIG. 17 is a diagram illustrating a resource mapping for an HARQ-ACK signal transmission for 2 DL CCs, each transmitting its own DL SA, using a DL CC specific offset, according to an embodiment of the present invention.

(71) Referring to FIG. 17, an outer BW region, starting from PRB 0 1710, is used for PUSCH transmissions and PUCCH transmissions other than dynamic HARQ-ACK transmissions 1720 (dynamic HARQ-ACK transmissions are in response to receptions of DL SAs). After N.sub.PUCCH HARQ-ACK resources 1730, corresponding, for example, to N.sub.PUCCH/18 PRBs (assuming 18 HARQ-ACK channels per PRB), the HARQ-ACK resources in response to DL SAs in the DL PCC are mapped 1740. After N.sub.PUCCH+ (0) HARQ-ACK resources 1750, corresponding, for example, to (N.sub.PUCCH+ (0))/18 PRBs, the HARQ-ACK resources in response to DL SAs in the DL SCC are mapped 1760. The HARQ-ACK resources for DL SAs in the DL PCC and for DL SAs in the DL SCC may partially or completely overlap (for example, complete overlapping occurs for n.sub.CCE(m)=n.sub.CCE and (m)=0 in Equation (7)). Finally, resources allocated to other PUCCH or PUSCH transmission follow 1770. The same mapping can apply from the other end of the BW (although not shown for brevity).

(72) While the present invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.