Control signal transmitting method and apparatus in relay station

Abstract

A method of transmitting a control signal of a relay station is provided. The method includes: receiving a control signal and data from a base station in a first subframe; and transmitting an acknowledgement/negative acknowledgement (ACK/NACK) signal for the data to the base station in a second subframe, wherein a radio resource for transmitting the ACK/NACK signal is determined by a radio resource to which the control signal received in the first subframe is allocated and by a logical physical uplink control channel (pucch) index received by using a higher layer signal.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application

In Equation 1 above, n_R-CCE may be a first CCE index of corresponding DCI reception in the R-PDCCH received by the RS in the subframe n-4. N⁽¹⁾_R-PUCCH denotes a logical PUCCH index, and can be configured by the higher layer signal. The R-PUCCH resource index can be used to determine a cyclic shift index and frequency used for transmission of a backhaul UL control signal. In addition, an orthogonal sequence index used to increase transmission capacity can also be determined by using the R-PUCCH resource index. That is, the RS can transmit the backhaul HARQ ACK/NACK in the subframe n by using n⁽¹⁾_R-PUCCH.

If the RS fails to receive the R-PDCCH in the subframe n-4 and receives the R-PDSCH, then the R-PUCCH resource index n⁽¹⁾_R-PUCCH used for R-PUCCH transmission (i.e., backhaul HARQ ACK/NACK transmission) in the subframe n can be determined by Table 3 below.

TABLE 3

Value of ‘TPC
Command for PUCCH’ n(1)R-PUCCH

‘00’               The first R-PUCCH resource index configured
                   by the higher layer signal
‘01’               The second R-PUCCH resource index configured
                   by the higher layer signal
‘10’               The third R-PUCCH resource index configured
                   by the higher layer signal
‘11’               The fourth R-PUCCH resource index configured
                   by the higher layer signal.

FIG. 12 shows an example of allocation of a resource block (RB), to which a PUCCH or R-PUCCH is allocated, and a logical PUCCH index.

Referring to FIG. 12, RBs 124 and 125 to which the R-PUCCH is allocated can be located adjacent to RBs 121, 122, and 123 for transmitting the PUCCH in a frequency domain. In addition, the RBs 124 and 125 to which the R-PUCCH is allocated can be allocated to a frequency band shifted in a direction of a PUSCH region (see FIG. 8).

The number of RBs that can be supported as a mixed RB in each slot is equal to or less than one. Different types of control information can be multiplexed in the mixed RB. The mixed RB of FIG. 12 is an RB used for combining the PUCCH format 1/1a/1b and the PUCCH format 2/2a/2b. When one UE transmits an SR by using the mixed RB, another UE in a cell can transmit a CQI by using the mixed RB (see 122). A normal RB is an RB used for one PUCCH format, e.g., the PUCCH format 1/1a/1b or the PUCCH format 2/2a/2b.

For RBs to which the PUCCH or R-PUCCH is allocated, a logical PUCCH index can be logically allocated first to a PUCCH resource and then can be allocated to an R-PUCCH resource. In other words, the logical PUCCH index is allocated by separating the PUCCH resource allocated to the UE and the R-PUCCH resource allocated to the RS. Herein, the PUCCH resource is a resource used for transmission of a control signal by a Ma UE through the PUCCH. The R-PUCCH resource is a resource used by the RS for transmission of a backhaul UL control signal through the R-PUCCH. The PUCCH resource and the R-PUCCH resource can be identified by the logical PUCCH index. Herein, the same mapping as a physical PUCCH index can be used for the logical PUCCH index, or mapping considering an RB-based allocation can be used for the logical PUCCH index. That is, although a start point of the R-PUCCH is reported by using a logical index, it is also possible to allocate the logical index to a first point of the physical RB when mapping to the physical index. This is a case where mapping is performed by separating the R-PUCCH and the PUCCH based on not only the logical RB but also the physical RB. Of course, continuous allocation is also possible without separation.

FIG. 13 shows an example of logical PUCCH index allocation.

Referring to FIG. 13, a logical PUCCH index is allocated in the ascending order starting from 0. The logical PUCCH index can be first allocated for a CQI, SR, and semi-persistent scheduling (SPS) ACK/NACK signal allocated to a Ma UE. Then, the logical PUCCH index is allocated for a dynamic ACK/NACK signal allocated to the Ma UE, and is then allocated for an R-PUCCH resource. Herein, the SPS ACK/NACK is an ACK/NACK for DL data transmitted through the SPS. A BS can transmit N⁽¹⁾_PUCCH to the Ma UE as the logical PUCCH index to indicate a PUCCH transmission resource capable of transmitting UL control information.

The BS can transmit N⁽¹⁾_R-PUCCH to an RS as the logical PUCCH index to indicate an R-PUCCH transmission resource capable of transmitting backhaul UL control information. The logical PUCCH index value N⁽¹⁾_R-PUCCH transmitted to the RS may indicate a first index of a physical RB which is the closest in location when a logical index is divided physically, or unlike this, in order to reduce resource waste, it can be mapped to consecutive PUCCH index resources irrespective of division of the physical RB. According to the logical PUCCH index allocation, a PUCCH resource allocated to the legacy UE and an R-PUCCH resource allocated to the RS are divided logically/physically when allocating the logical PUCCH index, and thus it is possible to allocate a backhaul UL control information resource of the RS without having an effect on the legacy LTE system or LTE UE. That is, backward compatibility with the legacy system can be maintained.

FIG. 14 shows another example of logical PUCCH index allocation.

The example of FIG. 14 is different from that of FIG. 13 in a sense that a logical PUCCH index N⁽¹⁾_R-PUCCH given to an RS is an offset value with respect to a logical PUCCH index N⁽¹⁾_PUCCH given to a Ma UE. The RS can acquire an R-PUCCH resource index for transmitting backhaul UL control information by using N⁽¹⁾_PUCCH and N⁽¹⁾_R-PUCCH.

FIG. 15 and FIG. 16 show another example of logical PUCCH index allocation.

Referring to FIG. 15 and FIG. 16, a logical PUCCH index for a scheduling request (SR) and SPS ACK/NACK allocated to an RS can be separated from a logical PUCCH index for a dynamic ACK/NACK. That is, a start position on a resource for the dynamic ACK/NACK can be directly indicated by a logical PUCCH index N⁽¹⁾_R-PUCCH transmitted to the RS. The RS can acquire an RB (or subcarrier) allocated to the R-PUCCH from the R-PUCCH resource index obtained by Equation 1 above by using the N⁽¹⁾_R-PUCCH.

A resource 151 for the SPS ACK/NACK and SR of the RS can be configured by a higher layer signal and can be reserved. The RS can determine a resource index of an R-PUCCH to be transmitted in a subframe n by using the index N⁽¹⁾_R-PUCCH and the CCE index of the R-PDCCH received in a subframe n-4. In this case, N⁽¹⁾_R-PUCCH can indicate a first resource index for the dynamic ACK/NACK.

The example of FIG. 16 is different from that of FIG. 15 in a sense that a logical PUCCH index N⁽¹⁾_R-PUCCH given to the RS is an offset value with respect to a logical PUCCH index N⁽¹⁾_PUCCH given to a Ma UE. A first resource index for the dynamic ACK/NACK of the Ma UE can be indicated by N⁽¹⁾_PUCCH given to the Ma UE. A first resource index for a dynamic ACK/NACK of the RS can be indicated by N⁽¹⁾_R-PUCCH given to the RS.

FIG. 17 and FIG. 18 show another example of logical PUCCH index allocation.

Referring to FIG. 17 and FIG. 18, a logical PUCCH index can be allocated by separating an SPS resource region (e.g., a resource region for CQI, ACK/NACK, and SR) of a Ma UE and an RS from a resource region for a dynamic ACK/NACK of the Ma UE and the RS. For example, a logical PUCCH index can be first allocated for a CQI, SPS ACK/NACK, and SR allocated to the Ma UE and an SPS ACK/NACK and SR allocated to the RS, and thereafter can be allocated to a dynamic ACK/NACK allocated to the Ma UE and a dynamic ACK/NACK allocated to the RS. In this case, the logical PUCCH index can be allocated in the order of the dynamic ACK/NACK of the Ma UE and the dynamic ACK/NACK of the RS.

A BS can indicate a start position on a resource for the dynamic ACK/NACK by using the logical PUCCH index N⁽¹⁾_PUCCH transmitted to the Ma UE, and can indicate a start position on a resource for the dynamic ACK/NACK by using the logical PUCCH index N⁽¹⁾_R-PUCCH to be transmitted to the RS. The logical PUCCH index N⁽¹⁾_R-PUCCH to be transmitted to the RS directly indicates a location for the dynamic ACK/NACK in FIG. 17, whereas it is an offset value with respect to the logical PUCCH index N⁽¹⁾_PUCCH given to the Ma UE in FIG. 18.

FIG. 19 shows an R-PDCCH transmitted to a plurality of RS groups.

RS s can be classified into two groups according to whether an HARQ ACK/NACK is an SPS ACK/NACK or a dynamic ACK/NACK. In FIG. 19, RSs #1 to #K (hereinafter, an RS group A) can be an RS group to which the SPS ACK/NACK is applied, and RSs #K+1 to #M (hereinafter, an RS group B) can be an RS group to which the dynamic ACK/NACK is applied. RSs #M+1 to #N (hereinafter, an RS group C) can be an RS group to which the SPS ACK/NACK and the dynamic ACK/NACK are applied. In this case, a logical PUCCH index can be allocated independently for each RS group. Frequency bands including an R-PDCCH transmitted to the respective RS groups are denoted by ‘A’, ‘B’, and ‘C’.

FIG. 20 shows an example of allocating a logical PUCCH index independently for each RS group.

Such a method can be applied when an R-PUCCH resource index at which a backhaul UL ACK/NACK is transmitted is independent for each RS group. For example, assume that R-PUCCH resource indices 0 to 10 are reserved for the RS group A, R-PUCCH resource indices 0 to 20 are reserved for the RS group B, and R-PUCCH resource indices 0 to 15 are reserved for the RS group C. In this case, as shown in FIG. 20, a logical PUCCH index for the RS group A can be given to N⁽¹⁾_R-PUCCH. Then, the R-PUCCH resource index n⁽¹⁾_R-PUCCH can be determined such as n_R-CCE+N(¹)_R-PUCCH. A logical PUCCH index for the RS group B can be given to N⁽¹⁾_R-PUCCH+Δ₁, and n⁽¹⁾_R-PUCCH for the RS group B can be determined such as n_R-CCE+N⁽¹⁾_R-PUCCH+Δ₁. A logical PUCCH index for the RS group C can be given to N⁽¹⁾_R-PUCCH+Δ₁+Δ₂, and n⁽¹⁾_R-PUCCH for the RS group C can be determined such as n_R-CCE+N⁽¹⁾_R-PUCCH+Δ₁+Δ₂.

FIG. 21 shows another example of allocating a logical PUCCH index independently for each RS group.

The method of FIG. 21 is different from that of FIG. 20 in a sense that a logical PUCCH index N⁽¹⁾_R-PUCCH given to an RS group A is an offset value with respect to a logical PUCCH index N⁽¹⁾_PUCCH given to a Ma UE.

FIG. 22 shows another example of allocating a logical PUCCH index independently for each RS group.

A logical PUCCH index for each RS group has the same index gap Δ. As such, the logical PUCCH index can have the same index gap when a size of an R-PDCCH is equal to n_R-CCE. In this case, a logical PUCCH index N⁽¹⁾_R-PUCCH can be given commonly to each RS group, and only an offset of the logical PUCCH index (i.e., the index gap Δ) can be optionally given for each RS group. Therefore, signaling overhead can be reduced.

FIG. 23 shows another example of allocating a logical PUCCH index independently for each RS group. The example of FIG. 23 is different from that of FIG. 22 in a sense that N⁽¹⁾_R-PUCCH given to each RS group is an offset value with respect to a logical PUCCH index N⁽¹⁾_PUCCH given to a Ma UE.

In FIG. 20 to FIG. 23, logical PUCCH index regions ‘A’, ‘B’, and ‘C’ can be switched to on/off according to a traffic amount between a BS and an RS. A bitmap-type signal can be given for on/off of the logical PUCCH index region. For example, if the signal is given to ‘101’, it may imply that ‘A’ and ‘C’ are used and ‘B’ is unused. The BS can report whether to use each logical PUCCH index region by using the bitmap-type signal. Then, the RS can determine an R-PUCCH resource index by determining whether to use the logical PUCCH index region when determining a backhaul ULACK/NACK resource index.

A1 though N⁽¹⁾_R-PUCCH, Δ₁, and Δ₂ are expressed by a positive value in the description based on FIG. 20 to FIG. 23, the present invention is not limited thereto. That is, N⁽¹⁾_R-PUCCH, Δ₁, and Δ₂ may be a negative value. If these values are negative values, it implies that regions ‘A’, ‘B’, and ‘C’ can be arranged in a different order from that shown in the figures.

In addition, although a method of allocating a logical PUCCH index for determining an R-PUCCH resource index for a dynamic ACK/NACK has been exemplified in the aforementioned description, the present invention is not limited thereto. That is, the present invention is also applicable when determining an R-PUCCH resource index for a case of an SPS ACK/NACK, an SR, and a CQI.

FIG. 24 shows an example in which an R-PDCCH transmitted to a plurality of RS groups is configured such that all R-PDCCHs have one logical index. FIG. 25 shows a method of allocating a logical PUCCH index when an R-PDCCH has one logical index similarly to FIG. 24.

Referring to FIG. 24, when a plurality of R-PDCCHs are present in a frequency band which is divided physically, an index of each R-PDCCH, i.e., a CCE index, can be configured so that the index has a logically contiguous value. In this case, the logical PUCCH index can be configured as shown in FIG. 25. That is, a logical PUCCH index can be allocated by separating an SPS resource region (e.g., a resource region for CQI, ACK/NACK, and SR) of a Ma UE and an RS from a resource region for a dynamic ACK/NACK of the Ma UE and the RS. A logical PUCCH index can be first allocated for a CQI, SPS ACK/NACK, and SR allocated to the Ma UE and an SPS ACK/NACK and SR allocated to the RS, and thereafter a logical PUCCH index can be allocated to a dynamic ACK/NACK allocated to the Ma UE and a dynamic ACK/NACK allocated to an RS. In this case, the logical PUCCH index can be allocated in the order of the dynamic ACK/NACK of the Ma UE and the dynamic ACK/NACK of the RS. Then, a plurality of RS groups can determine an R-PUCCH resource index similarly to a method of determining an R-PUCCH resource index in one RS.

FIG. 26 is a block diagram showing an apparatus for wireless communication according to an embodiment of the present invention. The apparatus may be a part of an RS.

Referring to FIG. 26, an apparatus 800 for wireless communication includes a processor 810, a memory 820, and a signal generator 840. The memory 820 is coupled to the processor 810, and stores an operating system file. The processor 810 is coupled to the memory 820, and configures a backhaul UL control channel. The processor 810 acquires a CCE index through an R-PDCCH and a logical PUCCH index by using a higher layer signal to obtain an R-PUCCH resource index. A backhaul UL control signal is processed by using a radio resource allocated through an R-PUCCH resource index. The signal generator 840 generates a transmission signal to be transmitted through an antenna 890 from the backhaul UL control signal processed by the processor 810.

The signal generator 840 can generate a transmission signal based on an SC-FDMA scheme. For this, the signal generator 840 can include a discrete Fourier transform (DFT) unit 842 for performing DFT, a subcarrier mapper 844, and an inverse fast Fourier transform (IFFT) unit 846 for performing IFFT. The DFT unit 842 outputs a frequency-domain symbol by performing DFT on an input sequence. The subcarrier mapper 844 maps frequency-domain symbols to respective subcarriers. The IFFT unit 846 outputs a time-domain signal by performing IFFT on an input symbol. The time-domain signal is transmitted through the antenna 890 as a transmission signal. The time-domain signal generated by the signal generator 840 can be generated according to the SC-FDMA scheme.

While the present invention has been particularly shown and described with reference to exemplary 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 invention as defined by the appended claims. The exemplary embodiments should be considered in descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

Claims

1. A method of transmitting a control signal of a relay station, the method comprising:

receiving, by the relay station, a control signal and data from a base station in a first subframe sub-frame; and

transmitting, by the relay station, an acknowledgement/negative acknowledgement (ACK/NACK) signal for the data to the base station in a second subframe sub-frame,

wherein a radio resource for transmitting the ACK/NACK signal is determined by a radio resource to which the control signal received in the first subframe sub-frame is allocated and by a logical physical uplink control channel (pucch) index received by using a higher layer signal,

wherein the logical pucch index is allocated first to a pucch resource allocated to a macro user equipment coupled to the base station, is allocated second to a pucch resource allocated to an Semi-Persistent Scheduling (SPS) ACK/NACK and scheduling request signal resource allocated to the relay station, and is allocated third to a pucch resource allocated to a dynamic ACK/NACK resource allocated to the relay station, and

wherein the logical pucch index indicates the dynamic ACK/NACK resource allocated to the relay station directly or indicates the dynamic ACK/NACK resource allocated to the relay station by the offset value with respect to the logical pucch index value transmitted to the macro user equipment.

2. The method of claim 1, wherein the logical pucch index is first allocated to a pucch resource which is allocated to a macro user equipment coupled to the base station, and is then allocated to an R-pucch resource which is allocated to the relay station.

3. The method of claim 1, wherein the logical pucch index transmitted to the relay station is an offset value with respect to a logical pucch index value which is transmitted to a macro user equipment coupled to the base station.

4. The method of claim 1, wherein the logical pucch index is first allocated to a Semi-Persistent Scheduling (SPS) radio resource allocated to the macro user equipment coupled to the relay station and the base station and is then allocated to a dynamic radio resource allocated to the relay station and the macro user equipment.

5. The method of claim 1, wherein if the relay station fails to receive the control signal in the first frame, the ACK/NACK signal is transmitted through a radio resource determined according to a configuration given by a higher layer signal.

6. An apparatus for wireless communication, the apparatus comprising:

a signal generator for generating and transmitting a radio signal; and

a processor coupled to the signal generator,

wherein the processor receives a control signal and data from a base station in a first subframe sub-frame, and transmits an acknowledgement/negative acknowledgement (ACK/NACK) signal for the data to the base station in a second subframe sub-frame, wherein the ACK/NACK signal is allocated to a radio resource determined by a radio resource to which the control signal received in the first subframe sub-frame is allocated and a logical physical uplink control channel (pucch) index received by using a higher layer signal,

wherein the logical pucch index is allocated first to a pucch resource allocated to a macro user equipment coupled to the base station, is allocated second to a pucch resource allocated to an Semi-Persistent Scheduling (SPS) ACK/NACK and scheduling request signal resource allocated to the relay station, and is allocated third to a pucch resource allocated to a dynamic ACK/NACK resource allocated to the relay station, and

wherein the logical pucch index indicates the dynamic ACK/NACK resource allocated to the relay station directly or indicates the dynamic ACK/NACK resource allocated to the relay station by the offset value with respect to the logical pucch index value transmitted to the macro user equipment.

7. The method of claim 1, wherein the logical pucch, which is allocated for a relay link pucch (R-pucch) resource, includes backhaul uplink (UL) control information.

8. The method of claim 1, wherein the logical pucch index is used to determine a cyclic shift index and frequency used for transmission of an uplink (UL) signal.

9. The apparatus of claim 6, wherein the logical pucch, which is allocated for a relay link pucch (R-pucch) resource, includes backhaul uplink (UL) control information.

10. The apparatus of claim 6, wherein the logical pucch index is used to determine a cyclic shift index and frequency used for transmission of an uplink (UL) signal.