1. A signal transmitting apparatus, comprising:
a first memory that stores received data and re-orders the stored data;
an inverse fast Fourier transform (IFFT) unit that stores a twiddle factor for shifting an output of IFFT by the size of a cyclic prefix, and performs the IFFT on data sequentially transmitted from the first memory on the basis of the twiddle factor;
a second memory that stores data, which is to be used as the cyclic prefix, among output data from the IFFT unit;
a multiplexer that generates an OFDM (orthogonal frequency division multiplexing) symbol on the basis of the cyclic prefix stored in the second memory and the IFFT value; and
a controller that receives the size of the cyclic prefix from a user, and generates the twiddle factor based on a value obtained by dividing the size of the cyclic prefix that is multiplied by a predetermined value by a prescribed size of a fast Fourier transform (FFT) for the IFFT,
wherein the twiddle factor is generated according to a formula:
\u2147
j
\u2062
2
\u2062
\u03c0
\xd7
CP_SIZE
FFT_SIZE
\u2062
k
,
and
wherein a frequency conversion characteristics of the FFT is determined according to the following formula:
F
(
k
+
M
)
=
FFT
\u2061
(
f
n
\u2062
\u2147
j2\u03c0
\u2062
\u2062
Mn
N
)
.
2. The signal transmitting apparatus of claim 1, wherein the second memory sequentially stores data corresponding to the size of the cyclic prefix starting with initial output data among output data from the IFFT unit so as to store the cyclic prefix.
3. The signal transmitting apparatus of claim 2, wherein the multiplexer generates the OFDM symbol by copying the cyclic prefix and adding the copied cyclic prefix to an end portion of the IFFT value.
4. A signal transmitting method in a signal transmitting apparatus that transmits an Orthogonal Frequency Division Multiplexing (OFDM) symbol, the method comprising:
receiving data;
performing inverse fast Fourier transform (IFFT) on the data on the basis of a twiddle factor for shifting output data by the size of a cyclic prefix;
sequentially storing data corresponding to the size of the cyclic prefix starting with initial data among the transformed data; and
generating the OFDM symbol on the basis of the stored data and the transformed data,
wherein the size of the cyclic prefix is determined by a user, and
wherein the twiddle factor is generated based on a value obtained by dividing the size of the cyclic prefix that is multiplied by a predetermined value by a prescribed size of a fast Fourier transform (FFT) for the IFFT,
wherein the twiddle factor is generated according to a formula:
\u2147
j
\u2062
2
\u2062
\u03c0
\xd7
CP_SIZE
FFT_SIZE
\u2062
k
,
and
wherein a frequency conversion characteristics of the FFT is determined according to the following formula:
F
(
k
+
M
)
=
FFT
\u2061
(
f
n
\u2062
\u2147
j2\u03c0
\u2062
\u2062
Mn
N
)
.
5. The method of claim 4, further comprising:
storing the twiddle factor on the basis of the size of the cyclic prefix and the size of the FFT for the IFFT.
6. The method of claim 5, wherein the generating of the OFDM symbol includes:
copying the stored data; and
adding the copied data to the transformed data to generate the OFDM symbol.
7. An inverse fast Fourier transform (IFFT) apparatus for a signal transmitting apparatus in an Orthogonal Frequency Division Multiplexing (OFDM) system, the IFFT apparatus comprising:
a first memory that stores a twiddle factor for shifting an output of IFFT by the size of a cyclic prefix;
a first shift register that stores data subjected to a first butterfly computation;
a first butterfly unit that performs the first butterfly computation on the basis of received data and the data stored in the first shift register;
a first multiplier that multiplies data transmitted from the first butterfly unit by the twiddle factor in the first memory;
a second shift register that stores data subjected to a second butterfly computation;
a second butterfly unit that performs the second butterfly computation on the basis of data transmitted from the first multiplier and the data stored in the second shift register;
a second multiplier that multiplies data transmitted from the second butterfly unit by the pre-stored twiddle factor for fast Fourier transform (FFT);
a third shift register that stores data subjected to a third butterfly computation; and
a third butterfly unit that performs the third butterfly computation on the basis of data transmitted from the second multiplier and the data stored in the third shift register,
wherein the size of the cyclic prefix is determined by a user,
wherein the twiddle factor is generated based on a value obtained by dividing the size of the cyclic prefix that is multiplied by a predetermined value by a prescribed size of an FFT for the IFFT, and
wherein a frequency conversion characteristics of the FFT is determined according to the following formula:
F
(
k
+
M
)
=
FFT
\u2061
(
f
n
\u2062
\u2147
j2\u03c0
\u2062
\u2062
Mn
N
)
.
8. The IFFT apparatus of claim 7, further comprising
a controller that generates the twiddle factor,
wherein the controller generates the twiddle factor on the basis of the size of the cyclic prefix and the size of FFT for the IFFT.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for allowing a user equipment to transmit ACKNACK information in a multicarrier-supporting wireless communication system, the method comprising:
generating individual ACKNACK information in association with individual codewords received from a base station through N carriers (where N\u22672) in M downlink subframes (where M\u22672), wherein a number of bits of the individual ACKNACK information in association with the individual codewords received through the N carriers in the M downlink subframes exceeds a predetermined number of bits;
performing spatial bundling to individual ACKNACK information in association with individual codewords received through M+C\u22129 carriers among the N carriers and in the M downlink subframes; and
transmitting the spatially-bundled ACKNACK information and the remaining individual ACKNACK information without applying the spatial bundling, to the base station through one uplink subframe,
wherein C is a total sum of maximum numbers of codewords configured in each of the N carriers in one downlink subframe.
2. The method according to claim 1, wherein the spatial bundling is applied over individual ACKNACK information of several codewords in one downlink subframe and one carrier.
3. The method according to claim 1, wherein the (M+C\u22129) carriers are sequentially selected from a last logical indexed carrier from among a plurality of carriers, each of which transmits 2 codewords, from among the N carriers.
4. The method according to claim 1, wherein a total sum of numbers of bits of the spatially-bundled ACKNACK information and numbers of bits of the remaining individual ACKNACK information is identical to or less than the predetermined number of bits.
5. The method according to claim 1, wherein the wireless communication system is a time division duplex (TDD) system.
6. The method according to claim 1, wherein:
M is set to 2, 3, 4 or 9,
N is set to 2, 3, 4 or 5,
one or two codewords are transmitted in each of the N carriers, and
the predetermined number of bits is 20 bits.
7. A user equipment for transmitting ACKNACK information in a multicarrier-supporting wireless communication system, the user equipment comprising:
a receiver for receiving a downlink signal from a base station;
a transmitter for transmitting an uplink signal to the base station; and
a processor connected to the reception module and the transmission module so as to control operations of the user equipment,
wherein the processor is configured to:
generate individual ACKNACK information in association with individual codewords received from the base station through N carriers (where N\u22672) in M downlink subframes (where M\u22672), wherein a number of bits of the individual ACKNACK information in association with the individual codewords received through the N carriers in the M downlink subframes exceeds a predetermined number of bits;
perform spatial bundling to individual ACKNACK information in association with individual codewords received through M+C\u22129 carriers among the N carriers and in the M downlink subframes; and
transmit the spatially-bundled ACKNACK information and the remaining individual ACKNACK information without applying the spatial bundling, to the base station through one uplink subframe,
wherein C is a total sum of maximum numbers of codewords configured in each of the N carriers in one downlink subframe.
8. The user equipment according to claim 7, wherein the spatial bundling is applied over individual ACKNACK information of several codewords in one downlink subframe and one carrier.
9. The user equipment according to claim 7, wherein the (M+C\u22129) carriers are sequentially selected from a last logical indexed carrier from among a plurality of carriers, each of which transmits 2 codewords, from among the N carriers.
10. The user equipment according to claim 7, wherein a total sum of numbers of bits of the spatially-bundled ACKNACK information and numbers of bits of the remaining individual ACKNACK information is identical to or less than the predetermined number of bits.
11. The user equipment according to claim 7, wherein the wireless communication system is a time division duplex (TDD) system.
12. The user equipment according to claim 7, wherein:
M is set to 2, 3, 4 or 9,
N is set to 2, 3, 4 or 5,
one or two codewords are transmitted in each of the N carriers, and
the predetermined number of bits is 20 bits.