DESCRIPTION
TRANSMITTER
5 Field
[0001] The present invention relates to a transmitter that transmits a control signal in wireless communication.
Background
10 [0002] Conventionally, base stations and terminals that perform wireless communication periodically transmit and receive control signals to/from each other. The base station and the terminal convert information on a reception state such as a field strength of a reception signal with
15 the control signal and grasp a state of a mutual
transmission path. The base station that can grasp the state of the transmission path of the terminal instructs an operation of a multi-antenna transmitting/receiving system such as a modulation and coding scheme (MCS) and spatial
20 multiplexing signal separation and instructs a wireless
resource to be allocated to the terminal, to the terminal, and the base station realizes adaptive wireless transmission according to the state of the transmission path between the base station and the terminal. When the
25 adaptive wireless transmission is established, it is necessary for the base station and the terminal to accurately receive the control signals. In the transmission of the control signals, a high reception performance is required for noise interference immunity and
30 radio propagation path variation resistance due to fading. [0003] To obtain a high reception performance in the transmission of the control signal, generally, a transmission-side apparatus performs processing to increase

redundancy to the control signal by using an application of a low coding rate in error correction coding or an application of repetition processing and diffusion processing performed by using a diffusion sequence. In 5 addition, in a transmission-side apparatus, regarding the control signal, a modulation method having a long distance between signal points having the noise interference immunity such as Binary Phase Shift Keying (BPSK) or Quadrature Phase Shift Keying (QPSK) is normally employed
10 for a modulation multivalue. Hereinafter, the transmission of the control signal is referred to as control signal transmission, and the wireless transmission of data to be performed by exchanging the control signal is referred to as data transmission.
15 [0004] In a terminal moving at high speed, since a gap
is generated between a transmission path value estimated by using a pilot signal having a known pattern with the base station and a transmission path value of a signal to be demodulated, a detection performance of the signal to be
20 demodulated tends to deteriorate. Regarding the above problem, Patent Literature 1 discloses a technique for allocating a control signal at a symbol position adjacent to a pilot signal in control signal transmission of a long term evolution (LTE) system standardized by 3GPP
25 standardization. Since a transmission path estimation
error of the control signal can be reduced by arranging the control signal and the pilot signal adjacent to each other, the deterioration in the detection performance in the control signal transmission due to the transmission path
30 variation can be reduced.
[0005] In an uplink of the LTE system, single carrier block transmission (SCBT) which has a lower peak performance and a smaller load to a power amplifier than

those of orthogonal frequency division multiplex (OFDM) employed in a downlink, and this is referred to as a multi¬access system single carrier-frequency division multiple access (SC-FDMA) (Non Patent Literature 1). In the LTE 5 uplink, the control signal may be transmitted by using a physical uplink shared channel (PUSCH). When the PUSCH is used, the transmission-side apparatus separately encodes the data signal and the control signal and subsequently multiplexes the signals. After that, the transmission-side
10 apparatus applies an interleave to the multiplexed sequence to generate a SC-FDMA symbol. The pilot signals are allocated to the third and the thirteenth subframes, and the SC-FDMA symbol including the control signal is allocated at a position around the pilot signal so that the
15 reception performance of the control signal does not deteriorate.
[0006] Regarding a dispersion arrangement of the pilot signals in the SCBT, Patent Literature 2 discloses a technique for realizing efficient insertion of the pilot
20 signals while maintaining a low peak performance. The
dispersion arrangement of the pilot signals realized in the OFDM can also be realized in the SCBT. [0007] Generally, the transmission-side apparatus concentrates SC-FDMA control symbols which are SC-FDMA
25 symbols including the control signals around a SC-FDMA
pilot symbol which is a SC-FDMA symbol including the pilot signals. Accordingly, even in the high-speed moving environment, regarding the control signals, the reception-side apparatus can secure the detection accuracy of the
30 control signal by suppressing the influence of the
estimation error from the transmission path estimation result by the pilot signal to the minimum. However, in a case where all the SC-FDMA control symbols are concentrated

around the SC-FDMA pilot symbol, if the reception field intensity decreases due to the fading, there is a possibility that the reception-side apparatus cannot detect the control signal and that the data transmission cannot be 5 established. To avoid a drop in the reception field intensity due to the fading, the transmission-side apparatus increases an insertion rate of the SC-FDMA control signal symbols so that a situation in which the reception-side apparatus cannot detect the control signal 10 can be avoided.
Citation List
Patent Literature
[0008] Patent Literature 1: JP 2013-102505 A
15 Patent Literature 2: JP 2013-529015 A
Non Patent Literature
[0009] Non Patent Literature 1: 3GPP TS36.212 V9.2.0,
3rd Generation Partnership Project; Technical Specification
Group Radio Access Network; Evolved Universal Terrestrial 20 Radio Access (E-UTRA); Multiplexing and channel coding
(Release9), 2010-06
Summary Technical Problem
25 [0010] However, according to the related art, there has been a problem that the transmission efficiency is lowered when the insertion rate of the SC-FDMA control signal symbols is increased. [0011] The present invention has been made in view of
30 the above. An object of the present invention is to obtain a transmitter that can transmit a signal capable of improving a reception performance of a control signal of a receiver while avoiding reduction in a transmission

efficiency.
Solution to Problem
[0012] In order to solve the problem and achieve the 5 object, there is provided a transmitter including: a
multiplexing unit configured to orthogonalize and multiplex a data signal to a receiver and a control signal including control information used in reception processing of the data signal by the receiver in a frequency domain or to
10 orthogonalize and multiplex a pilot signal that is a known pattern with the receiver and the control signal in a frequency domain in a block including single carrier symbols. The transmitter includes a control unit configured to control multiplexing processing by the
15 multiplexing unit.
Advantageous Effects of Invention
[0013] According to the present invention, an effect can be obtained that a signal capable of improving a reception 20 performance of a control signal of a receiver can be
transmitted while reduction in a transmission efficiency is avoided.
Brief Description of Drawings 25 [0014] FIG. 1 is a block diagram illustrating an
exemplary configuration of a transmitter according to a
first embodiment.
FIG. 2 is a block diagram illustrating an exemplary
configuration of a control signal encoding unit according 30 to the first embodiment.
FIG. 3 is a block diagram illustrating an exemplary
configuration of a receiver according to the first
embodiment.

FIG. 4 is a block diagram illustrating an exemplary configuration of a control signal demodulating unit according to the first embodiment.
FIG. 5 is a diagram illustrating an exemplary 5 dispersion arrangement in which data signals and control signals are orthogonalized to each other in a frequency domain according to the first embodiment.
FIG. 6 is a flowchart illustrating an example of SCBT symbol generating processing by the transmitter according 10 to the first embodiment.
FIG. 7 is a flowchart illustrating an example of SCBT symbol receiving processing by the receiver according to the first embodiment.
FIGS. 8(a) and 8(b) are diagrams illustrating an 15 exemplary arrangement of SCBT symbols in the transmitter and an exemplary arrangement of SCBT symbols in a comparative example according to the first embodiment.
FIGS. 9(a) and 9(b) are diagrams illustrating an exemplary arrangement of SCBT symbols including the control 20 signals in the transmitter according to the first embodiment.
FIG. 10 is a diagram illustrating a hardware configuration for realizing the configuration of the transmitter according to the first embodiment. 25 FIG. 11 is a diagram illustrating a hardware
configuration for realizing the configuration of the receiver according to the first embodiment.
FIG. 12 is a block diagram illustrating an exemplary configuration of a synchronization processing unit 30 according to a second embodiment.
FIG. 13 is a block diagram illustrating an exemplary configuration of a transmission/reception apparatus according to a third embodiment.

Description of Embodiments
[0015] A transmitter according to the embodiments of the present invention is described in detail below with 5 reference to the drawings. The present invention is not limited to the embodiments. [0016] First embodiment.
FIG. 1 is a block diagram illustrating an exemplary configuration of a transmitter 100 according to a first
10 embodiment of the present invention. In the SCBT
transmitter 100, an error correction encoder 101 performs error correction processing on an information bit sequence based on a coding rate instructed by a control unit 106. The error correction includes block codes, convolution
15 codes, and the like. However, the error correction is not limited to these. An interleaver 102 interleaves the information bit sequence to which the error correction processing has been performed based on an interleaver size or a pattern instructed by the control unit 106. The
20 interleave processing is performed to convert a burst error into a random error by switching an order of codewords. The mapping unit 103 is a data signal outputting unit which performs symbol mapping to the interleaved information bit sequence based on a multivalue instructed by the control
25 unit 106 and generates and outputs a data signal to a receiver to be described.
[0017] A pilot generation unit 104 is a pilot signal outputting unit which generates and outputs a pilot signal having a known pattern with the receiver by an instruction
30 by the control unit 106.
[0018] A control signal encoding unit 105 is a control signal outputting unit which generates a control bit sequence which is a signal of a bit sequence based on a

control instruction signal, performs mapping after encoding processing, and generates and outputs a control signal. It is assumed that the control signal include control information used in reception processing of the data signal 5 by the receiver. The detailed operation of the control signal encoding unit 105 is described later. [0019] The data signal generated by the mapping unit 103, the pilot signal generated by the pilot generation unit 104, and the control signal generated by the control signal
10 encoding unit 105 are input to a multiplexing unit 107 in a block formed of single carrier symbols that are SCBT symbols, and the multiplexing unit 107 multiplexes or selects the data signal, the pilot signal, and the control signal under the control of the control unit 106 and
15 outputs the signals.
[0020] The control unit 106 controls the generation of the data signals by the error correction encoder 101, the interleaver 102, and the mapping unit 103, the generation of the pilot signal by the pilot generation unit 104, the
20 generation of the control signal by the control signal
encoding unit 105, and the multiplexing processing by the multiplexing unit 107.
[0021] A guard interval (GI) inserting unit 108 inserts a guard interval (referred to as GI below) into the
25 multiplexed signal input from the multiplexing unit 107, and generates and outputs the SCBT symbol. [0022] FIG. 2 is a block diagram illustrating an exemplary configuration of the control signal encoding unit 105 according to the first embodiment. In the control
30 signal encoding unit 105, a control bit generating unit 111 generates and outputs a control bit sequence corresponding to the input control instruction signal. An encoding processing unit 112 performs redundancy processing on the

control bit sequence input from by the control bit generating unit 111. The redundancy processing is performed to improve the reception performance of the receiver by increasing noise interference immunity. 5 Specifically, the encoding processing unit 112 performs the redundancy processing such as error correction encoding, interleaving, repetition, or diffusion processing. The mapping unit 113 performs the symbol mapping on the control bit sequence, to which the redundancy processing has been
10 performed, input from the encoding processing unit 112
based on the multivalue instructed from the control unit 106, and generates and outputs the control signal. Note that the control signal encoding unit 105 may perform the redundancy processing such as the repetition or the
15 diffusion processing after the mapping.
[0023] Generally, in the SCBT, the transmission-side apparatus generates an SCBT pilot symbol based on the pilot signal and generates an SCBT symbol with a frame format in which the SCBT pilot symbol is inserted on the time axis
20 with respect to the SCBT data symbol generated from the data signal. Regarding the control signal, similarly to the pilot signal, the transmitting-side apparatus generates an SCBT control signal symbol by allocating the control signals to all the resources forming a single SCBT symbol
25 and multiplexes the SCBT control signal symbol between the SCBT data symbols. The transmitting-side apparatus can also multiplex the data signal and the control signal to form a single SCBT symbol. In this case, the data signal and the control signal are superimposed in a frequency
30 domain, and an f-th frequency component D(f) is expressed by the following formula (1). In the formula (1), the reference d(t) corresponds to the data signal, and the reference c(t) corresponds to the control signal. The

reference Nd corresponds to the number of data signals for the number of signals NFFT formed in the SCBT symbol. [0024] [Formula 1]
f +- Yl
wFFr-i £
+ E c(t) exp j27t.f —
t=Nr, \ N
1 f^"1 ( t ^
D(f)
'1'
E d(t) exp j2%f
W
V
FFT J)
JTT /
NFFT l t=o

5 [0025] The present embodiment is characterized by the control of the multiplexing processing of the multiplexing unit 107 by the control unit 106, that is, the multiplexing method of the data signal, the pilot signal, and the control signal by the multiplexing unit 107. The
10 multiplexing method of each signal in the transmitter 100 is described below.
[0026] Next, a configuration of the receiver 200 that receives the SCBT symbol transmitted from the transmitter 100 is described.
15 [0027] FIG. 3 is a block diagram illustrating an
exemplary configuration of the receiver 200 according to the first embodiment. In the SCBT receiver 200, a synchronization processing unit 201 detects a timing of outputting the reception signal of the SCBT symbol
20 including the data signal, the pilot signal, and the
control signal received from the transmitter 100 to a GI removing unit 202 in the subsequent stage, and outputs the reception signal at the detected timing. The GI removing unit 202 removes the GI inserted in the reception signal
25 and outputs the reception signal from which the GI has been removed. A fast Fourier transform (FFT) unit 203 performs FFT processing on the reception signal from which the GI has been removed to convert the reception signal in a time domain into the reception signal in the frequency domain.
30 A pilot separation unit 204 extracts the reception signal corresponding to the SCBT pilot symbol from the reception signals converted into those in the frequency domain, and

outputs the extracted signals to a control signal transmission path estimating unit 205.
[0028] The control signal transmission path estimating unit 205 is a first transmission path estimating unit that 5 estimates transmission path by linear interpolation and the like for the control signal to demodulate the control signal by using the pilot signal included in the reception signal corresponding to the SCBT pilot symbol extracted by the pilot separation unit 204. The control signal
10 transmission path estimating unit 205 generates a first
transmission path estimation value that is the transmission path estimation result obtained by the transmission path estimation and outputs the generated value to a control signal frequency domain equalization (FDE) unit 206. As
15 general transmission path estimation processing, a
transmission path estimation value corresponding to the pilot symbol can be obtained by dividing the reception signal of the pilot symbol by a pilot symbol value held by the receiver 200. Next, to obtain the transmission path
20 estimation value corresponding to the control signal, the
transmission path estimation value can be obtained by
linear interpolation and the like by using the transmission
path estimation value obtained from the pilot symbol.
[0029] The control signal FDE unit 206 is a first
25 frequency domain equalization unit that performs FDE processing on the control signal by using the first transmission path estimation value obtained from the control signal transmission path estimating unit 205. The FDE processing is processing for compensating for fading
30 and the like received by the SCBT symbol transmitted from the transmitter 100 in the transmission path to the receiver 200. In the SCBT, in general, the FDE processing is performed in the frequency domain by performing the FFT

processing on the reception signal and converting the reception signal into the signal in the frequency domain. In the FDE processing, by calculating an equalizing weighting corresponding to each frequency by using the 5 transmission path estimation value and performing a linear operation of multiplying the reception signal of the corresponding frequency by the equalizing weighting, interference components can be reduced. The SCBT is a transmission method that can perform equalization with such
10 an easy operation. The control signal FDE unit 206
performs the FDE processing on the control signal among the control signal and the data signal included in the reception signal of the remaining SCBT symbols from which the reception signal corresponding to the SCBT pilot symbol
15 has been extracted by the pilot separation unit 204 and outputs an equalized control signal which is an FDE processed control signal. The control signal FDE unit 206 outputs the data signal without performing the FDE processing.
20 [0030] An inverse fast Fourier transform (IFFT) unit 207 performs IFFT processing on the SCBT symbol including the equalized control signal and the data signal to which the FDE processing has not been performed, and generates an SCBT symbol which is obtained by converting the signal from
25 the frequency domain to the time domain. The data signal to which the FDE processing has not been performed may be accumulated in a memory and may be used by a data FDE unit 215 in the subsequent stage without performing the IFFT to reduce the operation amount.
30 [0031] The separation unit 208 separates the SCBT symbol, which is a signal in the time domain input from the IFFT unit 207, into the equalized control signal and the data signal. The separation unit 208 outputs the equalized

control signal separated from the SCBT symbol, which is the signal in the time domain, to the control signal demodulating unit 209. Also, the separation unit 208 outputs the data signal separated from the SCBT symbol, 5 which is the signal in the time domain, to an FFT unit 214. [0032] The control signal demodulating unit 209 performs decoding processing on the equalized control signal separated by the separation unit 208, the decoding processing being inverse processing corresponding to the
10 encoding processing of the control bit sequence performed by the control signal encoding unit 105 of the transmitter 100, specifically, the encoding processing unit 112. In addition, the control signal demodulating unit 209 demodulates the equalized control signal by hard decision,
15 and generates and outputs the demodulated equalized control signal, that is, a control bit sequence based on the equalized control signal. The operation of the control signal demodulating unit 209 is described below in detail. [0033] A control unit 210 instructs each component to
20 perform a demodulation operation or the like in the
reception processing performed by the receiver 200 based on the control bit sequence generated by the control signal demodulating unit 209. For example, when MCS information is allocated to a control bit sequence, the control unit
25 210 obtains a parameter, which has multivalue modulation, an coding rate, and a codeword length, to be used from a correspondence table of the control bit sequence and the MCS included in the control unit 210 and instructs the obtained parameter to a log likelihood ratio (LLR)
30 calculation unit 217, a deinterleaver 218, and an error
correction decoding unit 219. Since the control unit 210, the LLR calculation unit 217, the deinterleaver 218, and the error correction decoding unit 219 have the same

configurations as those in the related art, the MCS is described as an example in the following description. [0034] A control signal encoding unit 211 performs encoding processing on the equalized control signal 5 demodulated by the control signal demodulating unit 209, the encoding processing being similar to that of the control bit sequence performed by the control signal encoding unit 105 of the transmitter 100, specifically, the encoding processing unit 112, and outputs the encoded
10 equalized control signal. Here, it is assumed that the
output result of the control signal demodulating unit 209 be a hard decision value series. However, it is possible that a soft decision value sequence is outputted and encoding processing using a soft decision value series is
15 performed by the control signal encoding unit 211 based on the soft decision value series.
[0035] An FFT unit 212 is a replica generating unit for performing FFT processing on the equalized control signal encoded by the control signal encoding unit 211 and
20 generates a control signal replica which is a replica signal of the control signal.
[0036] After obtaining a transmission path estimation value corresponding to the control signal by using the control signal replica generated by the FFT unit 212, a
25 data transmission path estimating unit 213, which is a second transmission path estimating unit, estimates a transmission path by the linear interpolation and the like for the data signal to demodulate the data signal by using a transmission path estimation value corresponding to the
30 control signal and a transmission path estimation value corresponding to the pilot symbol which is the first transmission path estimation value input from the control signal transmission path estimating unit 205 to the data

transmission path estimating unit 213. The data transmission path estimating unit 213 generates a second transmission path estimation value that is a transmission path estimation result of the transmission path estimation 5 and outputs the second transmission path estimation value to the data FDE unit 215. The transmission path estimation value corresponding to the control signal by using the control signal replica can be obtained by dividing the reception signal of the control signal by the control
10 signal replica similarly to the control signal transmission path estimating unit 205.
[0037] The FFT unit 214 performs the FFT processing on the data signal separated by the separation unit 208 to convert the signal in the time domain into the signal in
15 the frequency domain.
[0038] The data FDE unit 215 is a second frequency domain equalization unit that performs the FDE processing for the data signals by using the second transmission path estimation value obtained from the data transmission path
20 estimating unit 213 and outputs an equalized data signal to which the FDE processing has been performed. The FDE processing by the data FDE unit 215 is similar to the FDE processing by the control signal FDE unit 206. [0039] An IFFT unit 216 performs the IFFT processing on
25 the equalized data signal to generate an equalized data signal which has been converted from the signal in the frequency domain to the signal in the time domain. [0040] The LLR calculation unit 217 calculates the LLR for the equalized data signal based on multivalue
30 modulation instructed in the MCS by the control unit 210. The deinterleaver 218 performs deinterleaving to the LLR calculated by the LLR calculation unit 217 based on the length of the codeword instructed in the MCS from the

control unit 210. The error correction decoding unit 219 performs error correction decoding on the signal deinterleaved by the deinterleaver 218 based on the coding rate and the length of the codeword instructed from the 5 control unit 210 to generate and output an information bit sequence.
[0041] FIG. 4 is a block diagram illustrating an exemplary configuration of the control signal demodulating unit 209 according to the first embodiment. In the control
10 signal demodulating unit 209, an LLR calculation unit 221 calculates an LLR for the equalized control signal as coping with an employed modulation method. A decoding processing unit 222 performs decoding processing on the LLR calculated by the LLR calculation unit 221, the decoding
15 processing being inverse processing corresponding to the encoding processing performed by the encoding processing unit 112 of the transmitter 100. In general, the decoding processing unit 222 performs the decoding processing of the LLR synchronization in a case where the encoding processing
20 of the encoding processing unit 112 of the transmitter 100 is the repetition. Also, the decoding processing unit 222 performs decoding processing for inversely diffusing the LLR sequence in a case where the encoding processing of the encoding processing unit 112 of the transmitter 100 is the
25 diffusion processing. The hard decision unit 223 performs a hard decision to the signal decoded by the decoding processing unit 222 and demodulates the equalized control signal, and generates and outputs an equalized control signal, that is, a control bit sequence based on the
30 equalized control signal. The configuration of the control signal demodulating unit 209 illustrated in FIG. 4 is an example. For example, in a case where the encoding processing of the transmitter 100 is the error correction

encoding, the control signal demodulating unit 209 obtains the control bit sequence by performing the error correction decoding.
[0042] In the present embodiment, the receiver 200 first 5 estimates the transmission path with respect to the control signal to which the redundancy processing has been performed so that the reception performance becomes higher than that of the data signal in the transmitter 100, and performs decoding and re-encoding. Next, the receiver 200
10 estimates the transmission path of the data signal by using the control signal replica generated after the re-encoding and the transmission path estimation value of the control signal. In a case where the transmission path of the data signal is estimated, the receiver 200 increases the number
15 of samples used for the linear interpolation and the like, and improves the accuracy of the transmission path estimation by using the transmission path estimation value of the control signal to improve the reception performance of the data signal. Also, the transmitter 100 can easily
20 and efficiently re-encodes the control signal with a low delay, and orthogonalizes the control signal and the data signal in the frequency domain or the control signal and the pilot signal and transmits the orthogonalized signals. [0043] Here, a difference between operations in the
25 following two cases is described. The cases include a case where FDE processing is concurrently performed to the control signal and the data signal by estimating the transmission path by using the pilot signal as in the related art and a case where the FDE processing of the data
30 signal is performed by estimating the transmission path of the data signal after the transmission path of the control signal has been estimated and the FDE processing of the control signal has been performed as in the present

10
15

embodiment.
[0044] In general, in a case where the data signal and the control signal are mixed in the SCBT symbol in the transmission-side apparatus, the data signal and the control signal are superimposed on each frequency in the frequency domain. Therefore, when the transmission path is estimated by using the control signal, it is necessary for the reception-side apparatus not only to generate the replica signal of the control signal but also to additionally generate the replica signal including the data signal. That is, it is necessary for the reception-side apparatus to generate a replica signal for the frequency component on which the data signal and the control signal are superimposed. The replica D(f) (hat) in the f-th frequency component is expressed by the following formula (2). Note that the reference d(t) (hat) indicates a data signal replica, and the reference c(t) (hat) indicates a control signal replica. [0045] [Formula 2]

20

D(f)

1
f
X d(t) exp j2nf
NFFT Lt = 0

t
N^

f
+ 2 c(t) exp j2nf

t
N^

[2)

25
30

[0046] When generating the replica signal including the control signal and the data signal, the reception-side apparatus has a disadvantage such that a processing calculation amount and a delay amount increase in processing including the error correction decoding. On the other hand, in a case where the processing does not include the error correction decoding, since the reception-side apparatus does not utilize the error correction, generation accuracy of the data signal replica is lower than that of the control signal replica, and an error tends to be larger, When the replica signal D(f) (hat) including the control signal and the data signal is indicated by using the data

signal replica d(t) (hat) and its error ed(t) and the control signal replica c(t) (hat) and its error ec(t), the following formula (3) is obtained. In a case where the error correction decoding is not included, the tendency to satisfy E[|ec(t) |2] < E[|ed(t) |2] is expected.
[0047] [Formula 3]

£ c\t) exp j2%f
t = Nd
\ NFFT -1
N
FFT J
£ {c(t) + ec(t)} exp j2%f
t = Nd
NFFr-l
f
2 ec(t) exp
t = Nd
j2%f
N
FFT J
D(f)
N„
D(f)

£ d(t) exp j2%f
N
FFT J
NFFT I t=o
f
wd-! ft
2 {d(t) + ed(t)} exp j2%f —
t=o { N
FFT J
t
1
f
j2%f
N
N„
2 ed(t) exp
FFT J

N

FFT J

[3]
[0048] In a case where the reception-side apparatus has a large error in the data signal replica, there is a possibility that the accuracy of the transmission path estimation is deteriorated due to the influence by the error of the data signal replica even when the transmission path is estimated in the frequency domain by using the replica signal D(f) (hat) including the control signal and the data signal.
[0049] To simply improve the accuracy of the transmission path estimation with a low delay in the reception-side apparatus, a transmission method is required for the transmission-side apparatus to maintain the orthogonalization between the control signal and the signal except for the control signal in the time domain or the frequency domain, specifically, between the control signal and the data signal or the pilot signal. Here, in a case where the signals are orthogonalized in the time domain in the transmission-side apparatus, the orthgonalization can be realized by time-multiplexing with the SCBT data symbol by forming the control signal with a single SCBT symbol.

However, the insertion of the plurality of SCBT control symbols are required to cope with a high-speed moving environment, and there is a disadvantage such that the transmission efficiency deteriorates. 5 [0050] Therefore, in the present embodiment, in the
transmitter 100, the data signal and the control signal are orthogonalized in the frequency domain, that is, orthogonally multiplexed in the frequency domain. The receiver 200 separately estimates the transmission paths of
10 the control signal and the data signal. Compared with a
case where the transmission paths of the signals including the data signal and the control signal are collectively estimated, the receiver 200 can reduce the operation amount in the individual transmission path estimation of the
15 transmission path estimations of the control signal and the data signal. The receiver 200 can suppress the operation amount and processing delay in replica generation required for transmission path estimation by using the control signals. Also, in a case where the receiver 200 is a
20 moving terminal, the dispersion arrangement of the control signals for the high-speed moving environment becomes available, and the transmitter 100 can prevent reduction in the transmission efficiency. The dispersion arrangement of the control signals is described later.
25 [0051] Generally, in a case where the transmission-side apparatus orthogonalizes the data signal and the control signal, the FFT processing is separately applied to each of the data signal and the control signal, and the obtained frequency components are distributedly arranged. Then, the
30 data signal and the control signal can be orthogonalized in the frequency domain by performing the IFFT. However, since different spectra are superimposed, there is a disadvantage such that a peak occurs in a time waveform.

[0052] Therefore, the transmitter 100 generates a frequency spectrum in which the data signals and the control signals are orthogonal to each other on the frequency axis. FIG. 5 is a diagram illustrating an 5 exemplary dispersion arrangement in which the data signals and the control signals are orthogonal to each other in the frequency domain according to the first embodiment. In the upper part of FIG. 5, the data signal, the control signal, and the synthesized frequency spectrum are illustrated.
10 Also, in the lower part of FIG. 5, the exemplary
arrangement of the SCBT symbols is illustrated. In the lower part of FIG. 5, the horizontal axis indicates a time, and the vertical axis indicates a frequency. A part which is a range 504 indicated by the dotted line is a single
15 SCBT symbol.
[0053] The transmitter 100 generates a repetitive waveform in which the data signal and the control signal are generated with a period of the number n in the frequency direction of the SCBT symbol. In the example in
20 FIG. 5, a repetitive waveform is generated in which the
repetition number n = 2 and the data signal and the control signal are alternately generated on the frequency. The repetition number n is a value indicating a generation frequency of each signal in the frequency direction. A
25 case of the repetition number n = 2 in FIG. 5 is a state in which the signals are generated once every two times, that is, every other time in the frequency direction. For example, regarding the data signal, the transmitter 100 forms a frequency spectrum of a comb-like spectrum 501 of a
30 data signal that has a repetitive waveform in which signals are alternately generated in the region in the frequency direction of the SCBT symbol. Also, regarding the control signal, the transmitter 100 forms a frequency spectrum of a

comb-like spectrum 502 of the control signal that has a repetitive waveform in which signals are alternately generated in the region in the frequency direction of the SCBT symbol by applying a frequency offset so that the 5 comb-like spectrum 501 of the data signal is not overlapped with the control signal in the frequency domain. By multiplexing the comb-like spectrum 501 of the data signal and the comb-like spectrum 502 of the control signal, the transmitter 100 can obtain a frequency spectrum 503 in
10 which components of the data signal and the control signal are orthogonal to each other on the frequency axis. Also, a case of the repetition number n = 3 is a state where the signals are generated once every three times, that is, every second times in the region in the frequency direction.
15 In this case, it is possible to synchronize the pilot signal, in addition to the data signal and the control signal. For example, the frequency offset is applied to the comb-like spectrum of the control signal generated every second times in the region in the frequency direction
20 so as not to be overlapped with the comb-like spectrum of the data signal generated every second times in the region in the frequency direction. In addition, a frequency offset is applied to the comb-like spectrum of the pilot signal generated every second times in the region in the
25 frequency direction so as not to be overlapped with the
comb-like spectra of the data signal and the control signal in the region in the frequency direction. The transmitter 100 multiplexes the comb-like spectra of the data signal, the control signal, and the pilot signal. The transmitter
30 100 may collectively form the comb-like spectra of the respective signals on the frequency axis. [0054] Patent Literature 2 discloses a multiplexing method for the orthogonalization by using the comb-like

spectrum for a combination of the data signal and the pilot signal. The transmitter 100 can obtain a waveform which suppresses a peak by performing multiplexing processing by using the data signal and the control signal, with a method 5 similar to the multiplexing and synchronizing processing by using the data signal and the pilot signal disclosed in Patent Literature 2.
[0055] Operations of the transmitter 100 and the receiver 200 are described with reference to a flowchart.
10 [0056] FIG. 6 is a flowchart illustrating an example of SCBT symbol generating processing by the transmitter 100 according to the first embodiment. The control unit 106 instructs the multiplexing unit 107 to disperse and arrange the data signals and the control signals in the SCBT symbol
15 in which the data signals and the control signals are
multiplexed (step SI). The control unit 106 instructs the value of the repetition number n in the repetitive waveform to the multiplexing unit 107. The control unit 106 causes the multiplexing unit 107 to convert the control signal and
20 the data signal into waveforms periodically generated on
the frequency axis and multiplex the control signal and the data signal in an arrangement in which the signals do not overlap with each other in the frequency domain. [0057] Based on the instruction by the control unit 106,
25 the multiplexing unit 107 converts the data signal input from the mapping unit 103 into the waveform indicated as the comb-like spectrum 501 of the data signal in FIG. 5, converts the control signal input from the control signal encoding unit 105 into the waveform indicated as the comb-
30 like spectrum 502 of the control signal in FIG. 5, and
multiplexes the comb-like spectrum 501 of the data signal and comb-like spectrum 502 of the control signal (step S2). The multiplexing unit 107 performs the multiplexing

processing on the SCBT symbol determined from the position of the SCBT pilot symbol including the pilot signal based on a SCBT frame format. The relationship between the SCBT symbol in which the control signals and the data signals 5 are multiplexed and the position of SCBT pilot symbol including the pilot signal is described later. [0058] The transmitter 100 can orthogonalize and multiplex the control signal and the pilot signal in the frequency domain, instead of orthogonalizing and
10 multiplexing the control signal and the data signal in the frequency domain. In this case, if the part of the data signal in FIG. 5 is replaced with the pilot signal, the transmitter 100 can cape with the case by the similar processing. In step SI in the flowchart illustrated in FIG.
15 6, the control unit 106 instructs the multiplexing unit 107 to perform the dispersion arrangement of the pilot signals and the control signals in the SCBT symbol in which the pilot signals and the control signals are multiplexed. The control unit 106 causes the multiplexing unit 107 to
20 convert the control signal and the pilot signal into
waveforms periodically generated on the frequency axis and multiplex the control signal and the pilot signal in an arrangement in which the signals do not overlap with each other in the frequency domain.
25 [0059] Also, in the transmitter 100, the control unit 106 instructs the multiplexing unit 107 to convert and multiplex the signals in the multiplexing unit 107. However, the present invention is not limited this. As described above, the control unit 106 controls the error
30 correction encoder 101, the interleaver 102, the mapping unit 103, the pilot generation unit 104, and the control signal encoding unit 105 in a general operation. [0060] Therefore, the control unit 106 may instruct the

repetition number n to the mapping unit 103 and may instruct the mapping unit 103 to output the data signal in the form of the comb-like spectrum 501 of the data signal in FIG. 5 when the data signal is output to the 5 multiplexing unit 107. The control unit 106 instructs the mapping unit 103 to output the data signals periodically generated on the frequency axis without overlapping with the control signal in the frequency domain. Similarly, it is possible that the control unit 106 instructs the control
10 signal encoding unit 105 of the repetition number n and instructs the control signal encoding unit 105 to output the control signal in the form of the comb-like spectrum 502 of the control signal in FIG. 5 when the control signal is output to the multiplexing unit 107. The control unit
15 106 instructs the control signal encoding unit 105 to
output the control signals periodically generated on the frequency axis without overlapping with the data signal in the frequency domain. Also, the control unit 106 instructs the multiplexing unit 107 to multiplex the control signal
20 and the data signal in an arrangement in which the signals do not overlap with each other in the frequency domain. As a result, it is preferable that the multiplexing unit 107 multiplex the signals input from the mapping unit 103 and the control signal encoding unit 105, and thus a load of
25 the conversion of the signals by the multiplexing unit 107 can be reduced.
[0061] In a case where the control signal and the pilot signal are multiplexed, the control unit 106 instructs the repetition number n to the pilot generation unit 104
30 instead of the mapping unit 103 and instructs the pilot
generation unit 104 to output the data signal in the form of the comb-like spectrum 501 of the data signal in FIG. 5 when the data signal is output to the multiplexing unit 107.

In this case, the control unit 106 instructs the pilot generation unit 104 to output the pilot signals periodically generated on the frequency axis without overlapping with the control signal in the frequency domain. 5 Similarly, the control unit 106 instructs the control signal encoding unit 105 to output the control signals periodically generated on the frequency axis without overlapping with the pilot signal in the frequency domain. Also, the control unit 106 instructs the multiplexing unit
10 107 to multiplex the control signal and the pilot signal in an arrangement in which the signals do not overlap with each other in the frequency domain.
[0062] In a case where the control unit 106 issues an instruction to the control signal encoding unit 105, there
15 is no restriction on the control signal. The control
signal may be a symbol sequence such as PSK or quadrature amplitude modulation (QAM) and may be a phase rotation sequence such as a Zadoff-Chu sequence. Also, it is possible that the modulation method is changed within the
20 symbol sequence, and it is possible that a predetermined
phase and frequency deviation may be applied to each symbol. For example, it may be a form in which QPSK and n/4QPSK are mixed in a single symbol sequence and a form of a symbol sequence in which a phase or frequency offset has been
25 applied to the symbol sequence.
[0063] FIG. 7 is a flowchart illustrating an example of SCBT symbol receiving processing by the receiver 200 according to the first embodiment. The control signal transmission path estimating unit 205 estimates the
30 transmission path by the linear interpolation and the like for the control signal, in order to modulate the control signal, by using the SCBT pilot symbols (step Sll). [0064] The control signal FDE unit 206 performs the FDE

processing on the control signal converted into the signal in the frequency domain by the FFT processing, the FDE processing being performed by the linear operation for reducing the interference components in the frequency 5 domain by using the first transmission path estimation value obtained from the control signal transmission path estimating unit 205. After that, the control signal demodulating unit 209 demodulates the equalized control signal via the IFFT unit 207 and the separation unit 208
10 (step S12) .
[0065] The control signal encoding unit 211 performs the encoding processing on the control bit sequence obtained by demodulation. After that, the FFT unit 212 performs FFT processing to generate a control signal replica (step S13).
15 [0066] The data transmission path estimating unit 213
estimates the transmission path by the linear interpolation and the like for the data signal, in order to demodulate the data signal, by using the control signal replica and the first transmission path estimation value (step S14).
20 [0067] The data FDE unit 215 performs the FDE processing on the data signal converted into the signal in the frequency domain, the FDE processing being performed by the linear operation for reducing the interference components in the frequency domain by the FFT processing by using the
25 second transmission path estimation value obtained from the data transmission path estimating unit 213. After that, the LLR calculation unit 217, the deinterleaver 218, and the error correction decoding unit 219 demodulate the data signal (step S15).
30 [0068] In this way, the receiver 200 first estimates the transmission path with respect to the control signal with a high detection performance by using only the pilot signal and performs the FDE processing and the demodulation

processing on the control signal by using the obtained transmission path estimation result. The receiver 200 can obtain a highly accurate transmission path estimation result by estimating the transmission path of the data 5 signal by using the pilot signal and the control signal, that is, by increasing the number of samples to be used. The receiver 200 can improve the reception performance of the data signal by performing the FDE processing and the demodulation processing of the data signal by using the
10 highly accurate transmission path estimation result. [0069] Also, in the receiver 200, since the FDE processing and the demodulation processing with respect to the control signal can be independently performed without relating to the FDE processing and the demodulation
15 processing of the data signal, the FDE processing and the demodulation processing for each signal can be realized with less operation and a low processing delay. [0070] Also, the transmitter 100 performs the dispersion arrangement of the controls signals to generate and
20 transmit the SCBT symbol so that the receiver 200 can avoid the influence caused by a drop in the reception signal strength due to fading, and an effect can be obtained that the control signal is stably detected. [0071] The method of multiplexing the data signal and
25 the control signal by the transmitter 100 has been
described here. Next, the positional relationship between the SCBT symbol obtained by multiplexing the data signal and the control signal and the SCBT symbol including the pilot signal is described.
30 [0072] FIG. 8(a) and 8(b) are diagrams illustrating an exemplary arrangement of the SCBT symbols of the transmitter 100 and an exemplary arrangement of the SCBT symbols in a comparative example according to the first

embodiment. The exemplary arrangement of the SCBT symbols of the comparative example is illustrated in FIG. 8(a), and the arrangement of the SCBT symbols according to the present embodiment is illustrated in FIG. 8(b). Also, in 5 each of FIGS. 8(a) and 8(b), the exemplary arrangement of the SCBT symbols is illustrated in the upper part, and an estimation error caused by the transmission path estimation is illustrated in the lower part. [0073] As illustrated in FIG. 8(a), in a case where the
10 transmission-side apparatus arranges a SCBT symbol 801 including the control signal around the SCBT symbol including the pilot signal, the reception-side apparatus performs the linear interpolation to the data signal by using the transmission path estimation value 803 obtained
15 from the control signal and the transmission path
estimation value 804 obtained from the subsequent pilot signal. In this case, there is a case where the reception-side apparatus can improve the estimation error than a case where the linear interpolation is performed on the data
20 signal by using transmission path estimation values 802 and 804 obtained from the pilot signal. However, since the interpolation interval is shortened by one time period, it is not possible to effectively improve the transmission path estimation error in the region of the data signal.
25 The dotted line in the lower part of FIG. 8(a) indicates the transmission path estimation value by the linear interpolation of the comparative example.
[0074] On the other hand, as illustrated in FIG. 8(b), when SCBT symbols 807 and 808 periodically including the
30 control signals are dispersed and arranged at equal
intervals between the known gap of the SCBT symbols 805 and 806 including the pilot signals in the transmitter 100, the receiver 200 can obtain a transmission path estimation

value with a short time period. The receiver 200 linearly interpolates the data signal by using transmission path estimation value 802 obtained from the pilot signal and the transmission path estimation value 809 obtained from the 5 control signal. Also, the receiver 200 linearly
interpolates the data signal by using the transmission path estimation values 809 and 810 obtained from the control signal. In addition, the receiver 200 linearly interpolates the data signal by using the transmission path
10 estimation value 810 obtained from the control signal and the transmission path estimation value 804 obtained from the pilot signal. Thus, the receiver 200 can realize highly accurate transmission path estimation for the data signal, and it is possible to reduce the estimation error
15 of the transmission path estimation value by the linear
interpolation than the comparative example. A dotted line illustrated in the lower part of FIG. 8(b) indicates the transmission path estimation value by the linear interpolation according to the present embodiment.
20 [0075] In the example in FIGS. 8(a) and 8(b), a case where there are two SCBT symbols including the control signals has been described. However, the present invention is not limited to this. In this case, in the transmitter 100, the control unit 106 causes the multiplexing unit 107
25 to generate a plurality of, for example, equal to or more than three SCBT symbols including the control signals, to arrange the single SCBT symbol including the control signal around the SCBT symbol including the pilot signal, and to disperse and arrange the other SCBT symbol including the
30 control signal. Then, the multiplexing unit 107 arranges
the SCBT symbols including the control signals according to
the instruction of the control unit 106.
[0076] Next, a case where the transmitter 100

multiplexes the pilot signal and the control signal is described. FIGS. 9(a) and 9(b) are diagrams illustrating an exemplary arrangement of the SCBT symbols, including the control signal, of the transmitter 100 according to the 5 first embodiment. In FIG. 9(a), a dispersion arrangement 1 is illustrated in which some control signals are arranged around the pilot signal and some control signals are dispersed from the pilot signals. In FIG. 9(b), a dispersion arrangement 2 is illustrated in which the pilot
10 signals and the control signals are multiplexed and some control signals are dispersed from the pilot signals. [0077] In the transmitter 100, in the dispersion arrangement 1, the SCBT symbol 901 including some control signals is arranged around the SCBT symbol including the
15 pilot signals, the SCBT symbol 902 including the other control signals is separately arranged from the pilot signals. In the transmitter 100, in the dispersion arrangement 2, similarly to the control signal or the data signal described above, the pilot signal forms the comb-
20 like spectrum, and the SCBT symbol 903 in which the pilot signal and the control signal are multiplexed is arranged apart from the SCBT symbol 904 including the other control signals. In FIG. 9(b), a larger region can be secured for the data signals than FIGS. 8(a) and 8(b) and FIG. 9(a).
25 Therefore, the transmission efficiency of the transmitter 100 can be improved.
[0078] Accordingly, while maintaining a reception performance quality of the control signal arranged around the pilot signal, the receiver 200 can improve a
30 transmission path estimation performance of the data signal by using the control signal dispersedly arranged from the pilot signal. Also, even if it is difficult to detect the pilot signal and the control signal around the pilot signal

due to the drop of the reception signal strength by fading by the dispersion arrangement of the control signals, the receiver 200 can expect to detect the subsequent control signals which are dispersedly arranged. Therefore, a 5 stable detection performance for the control signal can be obtained. In this way, the receiver 200 can improve the accuracy of the transmission path estimation of the data signal while improving the reception performance of the control signal. Note that in a case where the control unit
10 106 causes the multiplexing unit 107 to generate the
plurality of SCBT symbols including the control signals, the control unit 106 may control the number and the arrangement of the single carrier symbols including the control signals based on the state of the transmission path
15 between the receiver 200 and the transmitter 100. For
example, in a case where the state of the transmission path is excellent, the control unit 106 arranges the control signals as illustrated in FIG. 9(b), and the region of the data signal is larger than that in a case of FIG. 9(a).
20 Thus, the transmitter 100 and the receiver 200 can perform adaptive wireless transmission according to the state of the transmission path between the transmitter 100 and the receiver 200. [0079] Here, a hardware configuration for realizing the
25 components in the block diagram of the transmitter 100
illustrated in FIG. 1 is described. In the transmitter 100, the error correction encoder 101 is an error correction coding circuit, the interleaver 102 is an interleave circuit, the mapping unit 103 is a mapping circuit, the
30 pilot generation unit 104 is a pilot generation circuit,
the control signal encoding unit 105 is an encoding circuit, the multiplexing unit 107 is a multiplexing circuit, and the GI inserting unit 108 is a GI inserting circuit. In

the transmitter 100 illustrated in FIG. 1, a part of the components may be configured by software. FIG. 10 is a diagram illustrating a hardware configuration for realizing the configuration of the transmitter 100 according to the 5 first embodiment. A part of the configuration of the
transmitter 100 is realized by executing a program for each component stored in a memory 82 by a processor 81 and realizes the transmitter 100 together with a transmission device 83. The processor 81, the memory 82, and the
10 transmission device 83 are connected by a system bus 85. The plurality of processors 81 and the plurality of memories 82 may cooperate to execute the functions of the components illustrated in the block diagram of FIG. 1. [0080] Next, a hardware configuration for realizing each
15 components in the block diagram of the receiver 200
illustrated in FIG. 3 is described. In the receiver 200, the synchronization processing unit 201 is a synchronization processing circuit, the GI removing unit 202 is a GI removing circuit, the FFT units 203, 212, and
20 214 are FFT circuits, the pilot separation unit 204 is a pilot separation circuit, the control signal transmission path estimating unit 205 and the data transmission path estimating unit 213 are transmission path estimation circuits, the control signal FDE unit 206 and the data FDE
25 unit 215 are FDE circuits, the IFFT units 207 and 216 are IFFT circuits, the separation unit 208 is a separation circuit, the control signal demodulating unit 209 is a demodulation circuit, the control unit 210 is a control circuit, the control signal encoding unit 211 is an
30 encoding circuit, the LLR calculation unit 217 is an LLR calculation circuit, the deinterleaver 218 is a deinterleave circuit, and the error correction decoding unit 219 is an error correction decoding circuit. In the

receiver 200 illustrated in FIG. 3, a part of the components may be configured by software. FIG. 11 is a diagram illustrating a hardware configuration for realizing the configuration of the receiver 200 according to the 5 first embodiment. A part of the configuration of the
receiver 200 is realized by executing a program for each component stored in a memory 92 by a processor 91 and realizes the receiver 200 together with a reception device 94. The processor 91, the memory 92 and the reception
10 device 94 are connected by a system bus 95. The plurality of processors 91 and the plurality of memories 92 may cooperate to execute the functions of the components illustrated in the block diagram of FIG. 3. [0081] As described above, according to the present
15 embodiment, the transmitter 100 orthogonalizes the control signal and the data signal, or the control signal and the pilot signal in the frequency domain and transmits the orthogonalized signals. First, the receiver 200 estimates the transmission path of the control signal using the pilot
20 signal and performs the FDE processing and the demodulation processing on the control signal by using the transmission path estimation value of the control signal. Next, the receiver 200 estimates the transmission path of the data signal by using the control signal replica generated from
25 the demodulated control signal and the transmission path
estimation value of the control signal and performs the FDE processing and the demodulation processing on the data signal by using the transmission path estimation value of the data signal. Accordingly, by increasing the number of
30 samples of the transmission path estimation value and
estimating the transmission path of the data signal, the receiver 200 can improve the accuracy of the transmission path estimation of the data signal and can improve the

reception performance of the data signal. Also, the receiver 200 can suppress the operation amount and the processing delay in replica generation required for transmission path estimation by using the control signals. 5 [0082] The receiver 200 can improve the reception
performances of the control signal and the data signal by utilizing the control signal efficiently dispersed for the SCBT. In particular, in the high-speed moving environment, the receiver 200 can improve the reception performance by
10 reducing the transmission path estimation error in the data transmission and the deterioration in the reception performance due to the drop of a reception field intensity due to fading and can realize the stability of the reception performance of the control signal.
15 [0083] The transmitter 100 can stabilize the reception performance of the control signal in the receiver 200 by orthogonalizing the control signal to the data signal or the pilot signal on the frequency or time axis for the SCBT and dispersing and arranging the signals. In particular,
20 the transmitter 100 can realize the reduction in the
reception performance deterioration of the control signal of the receiver 200 due to the drop in reception field intensity due to fading in the high-speed moving environment. Further, by orthogonalizing the control
25 signal to the pilot signal or the data signal on the
frequency axis in the transmitter 100, the receiver 200 separately performs the FDE processing and the demodulation processing on the control signal and the data signal. Therefore, it is possible to suppress the operation amount
30 and the processing delay.
[0084] Second embodiment.
In a second embodiment, a method is described for improving a synchronization performance of SCBT symbols by

utilizing a control signal for synchronization processing of a reception signal of an SCBT symbol received from a transmitter 100 in a receiver 200.
[0085] FIG. 12 is a block diagram illustrating an 5 exemplary configuration of a synchronization processing unit 201 according to the second embodiment. In the receiver 200, the synchronization processing unit 201 performs synchronization processing of the SCBT symbols. For example, the synchronization processing unit 201
10 performs mutual correlation processing on a reception
signal by using a pilot signal or a preamble sequence. The synchronization processing unit 201 detects a frame timing toffset of the SCBT symbol based on the correlation result CC (toffset) obtained by the mutual correlation processing. An
15 example of an operational expression of the mutual
correlation calculation when it is assumed that the length of the mutual correlation sequence be L is expressed by Formula (4). Note that the reference r(t) indicates a reception signal, and the reference x(t) indicates a
20 sequence used in the mutual correlation. [008 6] [Formula 4]
CC(toffset) = Tr(t + toffset)x\t) ... (4)
t=0
[0087] Generally, the sequence x(t) is used in a sequence in which the preamble or the pilot signal is used
25 for the mutual correlation. However, in the present embodiment, some of the dispersedly arranged control signals are used as x(t). Here, as an example, the dispersion arrangement 2 illustrated in FIG. 9(b) is described as a premise. However, the arrangement of the
30 control signals is not limited to this.
[0088] In the synchronization processing unit 201, a mutual correlation sequence outputting unit 231 outputs a

mutual correlation sequence used to calculate the mutual correlation with the reception signal by a mutual correlation calculation unit 232. Specifically, the mutual correlation sequence outputting unit 231 outputs candidate 5 sequences 1, 2, ..., and Nseq of the mutual correlation sequence in which Nseq control signal components corresponding to the control signals that can be generated by the transmitter 100 are multiplexed with a single pilot component corresponding to the pilot signal that can be
10 generated by the transmitter 100. For example, the mutual correlation sequence outputting unit 231 accumulates candidate sequences 1, 2, ..., and Nseq which are the mutual correlation sequences of a plurality of patterns and outputs a mutual correlation sequence under the control by
15 the mutual correlation calculation unit 232. Alternatively, the mutual correlation sequence outputting unit 231 generates the pilot signal with a pilot component illustrated in FIG. 12 under the control by the mutual correlation calculation unit 232 and generates the control
20 signal with a control signal component illustrated in FIG. 12. Then, the mutual correlation sequence outputting unit 231 synthesizes the generated pilot signal and the generated control signal, and generates and outputs the candidate sequences 1, 2, ..., and Nseq which are the mutual
25 correlation sequences.
[0089] The mutual correlation calculation unit 232 calculates the mutual correlation between the reception signal of the SCBT symbol received from the transmitter 100 and the mutual correlation sequence output from the mutual
30 correlation sequence outputting unit 231. Specifically, the mutual correlation calculation unit 232 calculates a mutual correlation value between the reception signal of the received SCBT symbol and each mutual correlation

sequence from the mutual correlation sequence outputting unit 231 by using a mutual correlation function indicating the similarity of two signals as a numerical value. [0090] A timing detector 233 holds the calculation 5 result which is a mutual correlation value for each mutual correlation sequence of which the mutual correlation is calculated by the mutual correlation calculation unit 232 and detects a timing to output a reception signal based on the calculation result of the mutual correlation
10 calculation. Specifically, the timing detector 233 detects the timing with the largest correlation value, that is, the timing to output the reception signal based on the calculation result of the mutual correlation calculation and outputs the reception signal at the detected timing.
15 Since the timing detector 233 can estimate a control signal pattern based on the calculation result of the mutual correlation calculation, specifically, a control signal component illustrated in FIG. 12, the timing detector 233 may output information on the control signal pattern to the
20 GI removing unit 202 in the subsequent stage.
[0091] As described above, according to the present embodiment, the transmitter 100 generates and transmits the SCBT symbol with an arrangement configured by multiplexing the pilot signals and a part of the dispersed control
25 signals. Accordingly, the receiver 200 can improve the
synchronization detection performance while suppressing the deterioration in the transmission efficiency caused by the insertion of the control signals. Also, the receiver 200 can detect the control signal pattern before performing FDE
30 processing and the like.
[0092] In the present embodiment, the method for detecting the timing by the mutual correlation processing in the time domain in the synchronization processing by the

receiver 200 has been described. However, the present invention is not limited to this. Also, the receiver 200 can perform the synchronization processing for performing the mutual correlation calculation in the frequency domain. 5 [0093] Also, the configuration of the synchronization processing unit 201 illustrated in FIG. 12 is not limited to the case of a single antenna. That is, the configuration can be applied to a case of a multi-antenna. [0094] Third embodiment.
10 In the first and second embodiments, the transmitter 100 and the receiver 200 are separate and independent apparatuses. However, it is possible to provide a transmission/reception apparatus which includes the transmitter 100 and the receiver 200 and can
15 transmit/receive a wireless signal.
[0095] FIG. 13 is a block diagram illustrating an exemplary configuration of a transmission/reception apparatus 300 according to a third embodiment. The transmission/reception apparatus 300 includes the
20 transmitter 100 and the receiver 200. The configurations and the operations of the transmitter 100 and the receiver 200 are the same as those in the first and second embodiments. [0096] In a case where the transmission/reception
25 apparatus 300 transmits and receives signals to/from a
terminal, by including the transmitter 100 and the receiver 200, the transmission/reception apparatus 300 can control an arrangement of control signals in the transmitter 100 and the number of control signals to be arranged based on a
30 reception state of a data signal of the receiver 200. [0097] The configurations illustrated in the above embodiment indicate exemplary contents of the present invention and can be combined with other known technique.

Further, the configurations illustrated in the embodiment can be partially omitted and changed without departing from the scope of the present invention.
5 Reference Signs List
[0098] 100 transmitter, 101 error correction encoder, 102 interleaver, 103, 113 mapping unit, 104 pilot generation unit, 105, 211 control signal encoding unit, 106, 210 control unit, 107 multiplexing unit, 108 GI
10 inserting unit, 111 control bit generating unit, 112 encoding processing unit, 200 receiver, 201
synchronization processing unit, 202 GI removing unit, 203, 212, 214 FFT unit, 204 pilot separation unit, 205 control signal transmission path estimating unit, 206
15 control signal FDE unit, 207, 216 IFFT unit, 208
separation unit, 209 control signal demodulating unit, 213 data transmission path estimating unit, 215 data FDE unit, 217, 221 LLR calculation unit, 218 deinterleaver, 219 error correction decoding unit, 222 decoding processing
20 unit, 223 hard decision unit, 231 mutual correlation sequence outputting unit, 232 mutual correlation calculation unit, 233 timing detector, 300 transmission/reception apparatus.

CLAIMS
1. A transmitter comprising:
a multiplexing unit configured to orthogonalize and multiplex a data signal to a receiver and a control signal 5 including control information used in reception processing of the data signal by the receiver in a frequency domain or to orthogonalize and multiplex a pilot signal that is a known pattern with the receiver and the control signal in a frequency domain in a block including single carrier 10 symbols; and
a control unit configured to control multiplexing processing by the multiplexing unit.
2. The transmitter according to claim 1, wherein
15 the control unit instructs the multiplexing unit to
convert the control signal and the data signal to waveforms periodically generated on a frequency axis and multiplex the control signal and the data signal in an arrangement where both signals do not overlap with each other in the
20 frequency domain or to convert the control signal and the pilot signal to waveforms periodically generated on the frequency axis and multiplex the control signal and the pilot signal in an arrangement where both signals do not overlap with each other in the frequency domain.
25
3. The transmitter according to claim 1, comprising:
a data signal outputting unit configured to output the data signal;
a pilot signal outputting unit configured to output 30 the pilot signal; and
a control signal outputting unit configured to output the control signal, wherein
the control unit causes

the data signal outputting unit to output the data signal periodically generated on the frequency axis without overlapping with the control signal in the frequency domain,
the pilot signal outputting unit to output the pilot 5 signal periodically generated on the frequency axis without overlapping with the control signal in the frequency domain,
the control signal outputting unit to output the control signal periodically generated on the frequency axis without overlapping with the data signal or the pilot 10 signal in the frequency domain, and
the multiplexing unit to multiplex the control signal and the data signal in an arrangement where both signals do not overlap with each other in the frequency domain or multiplex the control signal and the pilot signal in an 15 arrangement where both signals do not overlap with each other in the frequency domain.
4. The transmitter according to any one of claims 1 to 3,
wherein
20 the control unit causes the multiplexing unit to
generate a plurality of single carrier symbols including the control signals, arrange the one single carrier symbol including the control signal around a single carrier symbol including the pilot signal, and disperse and arrange the
25 other single carrier symbols including the control signals.
5. The transmitter according to claim 4, wherein
the control unit controls the arrangement of the other single carrier symbols including the control signals based 30 on a state of a transmission path between the receiver and the transmitter.