Multiplexing control and data information from a user equipment

Abstract

Methods and apparatus are provided for a User Equipment to transmit acknowledgement information together with data information to a base station during a Transmission Time Interval. A number of nominal resources for the transmission of the first set of AIBs is compared to a number of resources available to the UE for transmission of the acknowledgement information. The first set of AIBs is transmitted if the number of nominal resources is less than or equal to the number of available resources. A second set of AIBs is selected from the first set of AIBs and bundling operations are performed over respective distinct subsets of AIBs in the second set of AIBs to obtain a third set of AIBs if the number of nominal resources is greater than the number of available resources. The third set of AIBs and a fourth set of AIBs are transmitted.

Claims

1. A method for a user equipment (UE) to transmit acknowledgement information together with data information during a transmission time interval (TTI), the acknowledgement information initially having a first set of hybrid automatic repeat request acknowledgement (HARQ-ACK) information bits, the method comprising the steps of: determining a number of required resources for transmission of the first set of HARQ-ACK information bits; comparing the number of required resources to a number of available resources available for transmission of the acknowledgement information; determining that the number of required resources is greater than the number of available resources; selecting a second set of HARQ-ACK information bits from the first set of HARQ-ACK information bits and performing one or more adaptive bundling operations over respective one or more distinct subsets of HARQ-ACK information bits in the second set of HARQ-ACK information bits to obtain a third set of HARQ-ACK information bits in response to the number of required resources being greater than the number of available resources, wherein at least one of the one or more adaptive bundling operations generates a smaller number of HARQ-ACK information bits than a number of HARQ-ACK information bits in the respective distinct subset of HARQ-ACK information bits; and transmitting the third set of HARQ-ACK information bits and a fourth set of HARQ-ACK information bits, wherein the fourth set of HARQ-ACK information bits is obtained from HARQ-ACK information bits that belong in the first set but not in the second set, wherein the one or more adaptive bundling operations are performed in a spatial domain until the number of required resources is not larger than the number of available resources, and wherein the one or more adaptive bundling operations generate an adaptive number of bundled HARQ-ACK information bits.

2. The method of claim 1, wherein the UE determines the first set of HARQ-ACK information bits based on information provided through a control channel or through higher layer signaling.

3. The method of claim 1, wherein each distinct subset of HARQ-ACK information bits contains HARQ-ACK information bits corresponding to data transport blocks the UE is configured to receive in a data channel.

4. The method of claim 3, wherein the at least one of the one or more adaptive bundling operation generates a HARQ-ACK information bit of value “1” if each HARQ-ACK information bit in the respective distinct subset of HARQ-ACK information bits has value “1” and generates a HARQ-ACK information bit of value “0” if any HARQ-ACK information bit in the respective distinct subset of HARQ-ACK information bits has value “0”.

5. The method of claim 1, wherein each distinct subset of HARQ-ACK information bits contains HARQ-ACK information bits corresponding to data transport blocks the UE may receive over a number of TTIs that is informed to the UE either through higher layer signaling or through a control channel.

6. The method of claim 1, wherein the second set of HARQ-ACK information bits is the same as the first set of HARQ-ACK information bits and the fourth set of HARQ-ACK information bits is empty.

7. The method of claim 1, wherein the number of required resources is represented by a number of encoded symbols for the acknowledgement information, and the number of available resources is represented by four times a number of resource elements for a physical uplink shared channel (PUSCH) transmission bandwidth in a subframe.

8. The method of claim 1, before the step of transmitting the third set of HARQ-ACK information bits and the fourth set of HARQ-ACK information bits, further comprising: determining the number of required resources for transmission of the first set of HARQ-ACK information bits; when the number of required resources is still greater than the number of available resources, performing one or more adaptive bundling operations in a time domain over respective one or more distinct subsets of HARQ-ACK information bits in the second set of HARQ-ACK information bits to obtain the third set of HARQ-ACK information bits.

9. A user equipment (UE) apparatus for transmitting acknowledgement information together with data information during a transmission time interval (TTI), the acknowledgement information initially having a first set of hybrid automatic repeat request acknowledgement (HARQ-ACK) information bits, the apparatus comprising: a computing unit for computing a number of required resources for transmission of the first set of HARQ-ACK information bits; a comparator for comparing the number of required resources for the transmission of the first set of HARQ-ACK information bits to a number of available resources available to the UE apparatus for the transmission of the acknowledgement information; a selector for selecting a second set of HARQ-ACK information bits from the first set of HARQ-ACK information bits; a bundling unit for determining that the number of required resources is greater than the number of available resources and performing one or more adaptive bundling operations over respective one or more distinct subsets of HARQ-ACK information bits in the second set of HARQ-ACK information bits to obtain a third set of HARQ-ACK information bits in response to the number of required resources being greater than the number of available resources, wherein at least one of the one or more adaptive bundling operations generates a smaller number of HARQ-ACK information bits than a number of HARQ-ACK information bits in the respective distinct subset of HARQ-ACK information bits; and a transmitter for transmitting the third set of HARQ-ACK information bits and a fourth set of HARQ-ACK information bits, wherein the fourth set of HARQ-ACK information bits is obtained from HARQ-ACK information bits that belong in the first set but not in the second set, wherein the bundling unit is configured to perform the one or more adaptive bundling operations in a spatial domain until the number of required resources is not larger than the number of available resources, and wherein the one or more adaptive bundling operations generate an adaptive number of bundled HARQ-ACK information bits.

10. The apparatus of claim 9, wherein the first set of HARQ-ACK information bits is determined based on information provided to the UE apparatus through a control channel or through higher layer signaling.

11. The apparatus of claim 9, wherein each distinct subset of HARQ-ACK information bits contains HARQ-ACK information bits corresponding to data transport blocks the UE apparatus is configured to receive in a data channel.

12. The apparatus of claim 11, wherein the at least one of the one or more adaptive bundling operation generates a HARQ-ACK information bit of value “1” if each HARQ-ACK information bit in the respective distinct subset of HARQ-ACK information bits has value “1” and generates a HARQ-ACK information bit of value “0” if any HARQ-ACK information bit in the respective distinct subset of HARQ-ACK information bits has value “0”.

13. The apparatus of claim 9, wherein each distinct subset of HARQ-ACK information bits contains HARQ-ACK information bits corresponding to data transport blocks the UE apparatus may receive over a number of TTIs that is informed to the UE apparatus either through higher layer signaling or through a control channel.

14. The apparatus of claim 9, wherein the second set of HARQ-ACK information bits is the same as the first set of HARQ-ACK information bits and the fourth set of HARQ-ACK information bits is empty.

15. The apparatus of claim 9, wherein the number of required resources is represented by a number of encoded symbols for the acknowledgement information, and the number of available resources is represented by four times a number of resource elements for a physical uplink shared channel (PUSCH) transmission bandwidth in a subframe.

16. The apparatus of claim 9, wherein when the number of required resources is still greater than the number of available resources, the bundling unit is further configured to perform one or more adaptive bundling operations in a time domain over respective one or more distinct subsets of HARQ-ACK information bits in the second set of HARQ-ACK information bits to obtain the third set of HARQ-ACK information bits.

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 when taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a diagram illustrating a conventional PUSCH subframe structure;

(3) FIG. 2 is a block diagram illustrating a conventional transmitter for transmitting data and HARQ-ACK signals in a PUSCH;

(4) FIG. 3 is a block diagram illustrating a conventional receiver for receiving data and HARQ-ACK signals in the PUSCH;

(5) FIG. 4 is a diagram illustrating conventional multiplexing of HARQ-ACK sub-carriers and data sub-carriers in a PUSCH;

(6) FIG. 5 is a diagram illustrating the principle of dynamic application of HARQ-ACK bundling by a UE, according to an embodiment of the present invention;

(7) FIG. 6 is a diagram illustrating a process for adaptively determining the number of bundled HARQ-ACK information bits, according to an embodiment of the present invention;

(8) FIG. 7 is a diagram illustrating a HARQ-ACK bundling process for O.sub.initial−O.sub.bundle+1 HARQ-ACK information bits into a single HARQ-ACK information bit, according to an embodiment of the present invention; and

(9) FIGS. 8 and 9 are diagrams illustrating a bundling process operating in a consecutive manner across the initial HARQ-ACK information bits, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

(10) Embodiments of the present invention are described in detail with reference to the accompanying drawings. The same or similar components may be designated by the same or similar reference numerals although they are illustrated in different drawings. Detailed descriptions of constructions or processes known in the art may be omitted to avoid obscuring the subject matter of the present invention.

(11) Additionally, although the embodiments of the present invention will be described below with reference to DFT-spread OFDM transmission, they also are applicable to all Frequency Division Multiplexing (FDM) transmissions in general and to Single-Carrier Frequency Division Multiple Access (SC-FDMA) and OFDM in particular.

(12) In accordance with an embodiment of the present invention, HARQ-ACK bundling in the PUSCH is dynamic and it is triggered when the number of HARQ-ACK coded symbols Q.sub.nominal′ required to achieve the target HARQ-ACK reception reliability exceeds the upper bound of 4.Math.M.sub.sc.sup.PPUSCH(Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH). As is subsequently further described, when triggered, HARQ-ACK bundling may apply in a predetermined manner either across all HARQ-ACK information bits in the spatial domain, time domain, or cell domain, or across all HARQ-ACK information bits in combinations of these domains.

(13) Both Q.sub.nominal′ and 4.Math.M.sub.sc.sup.PUSCH should be known to both the UE and the NodeB in order for the operation of dynamic HARQ-ACK bundling to be unambiguous. For Q.sub.nominal′, this requires that both the UE and the NodeB have the same understanding for the initial HARQ-ACK payload (initial number of HARQ-ACK information bits prior to HARQ-ACK bundling). This can be achieved by either the initial number of HARQ-ACK information bits being predetermined, depending on, for example, the number of DL cells the UE is configured to receive PDSCH or the number of DL TTIs for which the UE generates HARQ-ACK in the UL subframe, or being explicitly indicated to the UE by the NodeB through the UL SA, if any, scheduling the PUSCH transmission. For 4.Math.M.sub.sc.sup.PUSCH this requires that the UE and the NodeB have the same understanding of the PUSCH transmission BW, which, excluding incorrect operation conditions, is always the case.

(14) FIG. 5 illustrates the principle of dynamic HARQ-ACK bundling application by a UE, according to an embodiment of the present invention.

(15) Referring to FIG. 5, the UE first determines a number of coded symbols Q.sub.nominal′ in step 510. If Q.sub.nominal′≦4.Math.M.sub.sc.sup.PUSCH the HARQ-ACK bits are transmitted without any bundling using Q.sub.nominal′ symbols in step 520. If Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH, then HARQ-ACK bundling is applied in step 530.

(16) In accordance with another embodiment of the present invention, the number of initial HARQ-ACK information bits that are bundled is adaptive. In the previous embodiment, HARQ-ACK bundling is applied when Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH and, depending on the available domains and the domains involved in the bundling operation, it may reduce the number of HARQ-ACK information bits to a number that is smaller than the one required to achieve a target reception reliability by utilizing the available PUSCH resources.

(17) In order to minimize the impact from the information loss associated with HARQ-ACK bundling, the number of initial HARQ-ACK information bits that are bundled can also be adaptive. The adaptation can be based on the maximum number of HARQ-ACK information bits for which Q.sub.nominal′ is smaller than or equal to 4.Math.M.sub.sc.sup.PUSCH. Therefore, if Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH, the number of HARQ-ACK bits after adaptive HARQ-ACK bundling can be more than one HARQ-ACK bit and is determined as shown in Equation (4).

(18) $\begin{array}{cc}{O}_{\mathrm{bundle}}=\arg \underset{O_b}{\max }\left(Q_{\mathrm{nominal}}^{\prime }\left(O_b\right)\right)\mathrm{subject}\mathrm{to}{Q}_{\mathrm{nominal}}^{\prime }\le 4.Math.M_{\mathrm{sc}}^{\mathrm{PUSCH}}& \left(4\right)\end{array}$

(19) There are several approaches for a UE to implement the principle of adaptive HARQ-ACK bundling and generate an adaptive number of bundled HARQ-ACK information bits. One approach is to progressively decrease the number of HARQ-ACK information bits from the initial nominal value of O>1 (before any HARQ-ACK bundling) until the UE determines, as in Equation (4), a number of HARQ-ACK information bits O.sub.bundle for which it is Q.sub.nominal′≦4.Math.M.sub.sc.sup.PUSCH. HARQ-ACK bundling can start from a predetermined HARQ-ACK bit, such as the last HARQ-ACK information bit, or from a particular domain, such as the spatial domain, and continue if needed in the remaining domains.

(20) For example, considering for simplicity

(21) $Q_{\mathrm{nominal}}^{\prime }=\left(.Math.\frac{O.Math.{\beta }_{\mathrm{offset}}^{\mathrm{PUSCH}}}{Q_m.Math.R}.Math.\right)$
and assuming that 4.Math.M.sub.sc.sup.PUSCH=96, if a UE needs to convey O=6 HARQ-ACK information bits for which Q.sub.nominal′=120 then it needs to apply HARQ-ACK bundling. As O=5 HARQ-ACK bits require Q.sub.nominal′=100 and O=4 HARQ-ACK bits require Q.sub.nominal′=80, it is O.sub.bundle=4. Therefore, through HARQ-ACK bundling, the UE reduces the number of HARQ-ACK information bits by 2.

(22) FIG. 6 illustrates the process for adaptively determining the number of bundled HARQ-ACK information bits, according to an embodiment of the present invention.

(23) Referring to FIG. 6, the process is triggered in case Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH and the UE has more than 1 HARQ-ACK information bit to transmit (otherwise, HARQ-ACK bundling is not applicable), in step 610. In step 620, the number of HARQ-ACK information bits considered for transmission in the PUSCH is reduced by one by setting O=O−1. If O=1 in step 630, the process terminates by transmitting 1 HARQ-ACK information bit in step 640 using the respective number of symbols Q′ for O=1. If O≠1 in step 630, the UE examines whether Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH, in step 650. If Q.sub.nominal′≦4.Math.M.sub.sc.sup.PUSCH, the process follows 660 and continues by repeating step 620. If Q.sub.nominal′≦4.Math.M.sub.sc.sup.PUSCH, the process terminates by transmitting O HARQ-ACK information bits, in step 670, using the respective number of symbols Q′.

(24) Although the HARQ-ACK bundling process in FIG. 6 considers that the number of HARQ-ACK information bits is progressively reduced by one until it becomes either one or such that it can be transmitted in less than or equal to 4.Math.M.sub.sc.sup.PUSCH REs (or both), other reduction approaches may instead apply.

(25) In another approach, at each iteration of the adaptive HARQ-ACK bundling process, the reduction in the number of HARQ-ACK information bits can be by a predetermined number that is larger than one or by a predetermined percentage of the HARQ-ACK information bits that remain at the given iteration of the HARQ-ACK bundling process. For example about half the existing HARQ-ACK information bits can be bundled at each iteration by setting O=┌O/2┐ (or O=└O/2┘). Regardless of the exact reduction method for the number of HARQ-ACK information bits, the principle for adaptively determining their number based on the maximum resources available for their transmission applies.

(26) Several approaches also exist for the selection of the HARQ-ACK information bits that are bundled for adaptive HARQ-ACK bundling. This selection can be based on some predetermined rule, or on some prioritization for the bundling domain, or on both.

(27) In a first approach, the last (or the first) O.sub.initial−O.sub.bundle+1 HARQ-ACK information bits from the O.sub.initial HARQ-ACK information bits can be bundled into a single bit.

(28) FIG. 7 illustrates a HARQ-ACK bundling process for the last O.sub.initial−O.sub.bundle+1 HARQ-ACK information bits into a single HARQ-ACK information bit, according to an embodiment of the present invention.

(29) Referring to FIG. 7, O.sub.initial HARQ-ACK bits are generated in step 710. The last O.sub.initial−O.sub.bundle+1 HARQ-ACK bits of the initial O.sub.initial HARQ-ACK information bits are obtained in step 720, and bundled into a single HARQ-ACK information bit, in step 730. The information bits are bundled to an ACK if all are ACKs and are bundled to a NACK if any one is a NACK. A total of O.sub.bundle HARQ-ACK information bits are obtained, in step 740.

(30) In a second approach, HARQ-ACK bundling can be done in a consecutive fashion across the initial HARQ-ACK information bits by bundling the first and second HARQ-ACK information bits, the third and fourth HARQ-ACK bits and so on. If O.sub.initial−O.sub.bundle≦O.sub.bundle, the HARQ-ACK bundling process continues until O.sub.initial−O.sub.bundle bundled HARQ-ACK information bits are obtained. If O.sub.initial−O.sub.bundle>O.sub.bundle, the HARQ-ACK bundling process iteratively continues by obtaining ┌O.sub.initial/2┐ HARQ-ACK bits at the end of each iteration where O.sub.initial is the number of HARQ-ACK bits at the beginning of each iteration.

(31) FIG. 8 is a diagram illustrating a bundling process operating in a consecutive manner across the initial HARQ-ACK information bits, according to an embodiment of the present invention.

(32) Referring to FIG. 8, assuming for simplicity, that O.sub.intital−.sub.bundle≦O.sub.bundle, the first 2k−1, k=1, . . . , O.sub.initial−O.sub.bundle HARQ-ACK information bits are bundled with the first 2k, k=1, . . . , O.sub.initial−O.sub.bundle HARQ-ACK information bits. Each of even numbered first 2.Math.(O.sub.initial−O.sub.bundle) HARQ-ACK information bits 820 from initial O.sub.initial HARQ-ACK information bits 810 and each of odd numbered first 2.Math.(O.sub.initial−O.sub.bundle)−1 HARQ-ACK information bits 830 from the initial O.sub.initial HARQ-ACK information bits 810 are respectively bundled in block 840. The resulting O.sub.initial−O.sub.bundle bundled HARQ-ACK information bits are combined with the last (2.Math.O.sub.bundle−O.sub.initial) of the initial O.sub.initial HARQ-ACK information bits to finally transmit O.sub.bundle HARQ-ACK information bits.

(33) Alternatively, HARQ-ACK bundling may be prioritized to be performed first in the spatial domain, as the multiple TBs associated with the same PDSCH reception are likely to be either all correctly received or all incorrectly received, continuing with prioritizing HARQ-ACK bundling in the time domain in case of a TDD system, and finally having HARQ-ACK bundling in the cell domain in case the UE receives PDSCH in multiple cells of the communication system. Then, spatial-domain HARQ-ACK bundling (when applicable) can be first performed if Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH. If after spatial-domain HARQ-ACK bundling, it is still Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH, time-domain HARQ-ACK bundling (when applicable) can be performed next. Finally, if after both spatial-domain HARQ-ACK bundling and time-domain HARQ-ACK bundling, it is still Q.sub.nominal′>4.Math.M.sub.sc.sup.PUSCH, cell-domain HARQ-ACK bundling (when applicable) may be performed.

(34) Finally, as described by the embodiments of the invention, HARQ-ACK bundling in each domain may either be performed across all respective HARQ-ACK information bits in that domain (fixed bundling) or across only a number HARQ-ACK information bits determined so that, after bundling, it is Q.sub.nominal′≦4.Math.M.sub.sc.sup.PUSCH (adaptive bundling).

(35) 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 detail may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.