Signal transmission method and apparatus
Example signal transmission methods and apparatus are described. In an example method, a transmit end performs linear frequency modulation on Z data signals within frequency domain resources corresponding to K subcarriers to obtain a first signal. A frequency occupied by the first signal is within a frequency range of the frequency domain resources corresponding to the K subcarriers. A frequency occupied by each of data signals obtained through linear frequency modulation changes linearly with time.
1 . A method for transmitting signals, comprising:
performing, by a transmit end, linear frequency modulation on Z data signals within frequency domain resources corresponding to K subcarriers to obtain a first signal, wherein the first signal comprises a cyclic prefix signal, the cyclic prefix signal is a signal generated based on the Z data signals and cyclic prefix time, a frequency occupied by the first signal is within a frequency range of the frequency domain resources corresponding to the K subcarriers, and a frequency occupied by each of Z data signals obtained through linear frequency modulation changes linearly with time, and wherein:
a z th data signal in the Z data signals corresponds to M z time segments, and slopes of linear changes of the M z time segments are the same;
when M z >1, a start frequency of an M z th time segment is a lowest frequency in the frequency range, and an end frequency of an (M z −1) th time segment is a highest frequency in the frequency range; or
when M z >1, a start frequency of an M z th time segment is a highest frequency in the frequency range, and an end frequency of an (M z −1) th segment is a lowest frequency in the frequency range; and
each of K, M z , and Z is an integer greater than or equal to 1, and z ranges from 1 to Z.
2 . The method according to claim 1 , wherein the first signal is an analog signal, the frequency of the first signal is within a first range, and the first range is
[
(
k
0
-
1
2
)
Δ
f
,
(
k
0
-
1
2
+
K
)
Δ
f
]
,
or the first range is
[
(
k
0
-
1
2
+
K
)
Δ
f
,
(
k
0
-
1
2
)
Δ
f
]
,
and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers, k 0 is an integer, and Δf is a subcarrier width.
3 . The method according to claim 1 , wherein the first signal is a digital signal, the frequency of the first signal is within a second range, and the second range is [k 0 , k 0 +K−1], or the second range is [k 0 +K−1, k 0 ], and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers, and k 0 is an integer.
4 . The method according to claim 1 , wherein the first signal further comprises a non-cyclic prefix signal, and the non-cyclic prefix signal is a signal generated based on the Z data signals and non-cyclic prefix time.
5 . The method according to claim 1 , wherein the performing, by a transmit end, linear frequency modulation on Z data signals within frequency domain resources corresponding to K subcarriers comprises:
performing, by the transmit end, phase shifting on the Z data signals;
performing, by the transmit end, K-point general inverse discrete Fourier transform (GIDFT) on data signals obtained through phase shifting to generate a second signal;
performing, by the transmit end, phase shifting on the second signal based on non-cyclic prefix time {n 1 , . . . , n 1 +K−1} to generate a third signal;
transforming, by the transmit end, the third signal to a frequency domain by performing K-point general discrete Fourier transform (GDFT);
mapping, by the transmit end, the third signal onto the K subcarriers to obtain a fourth signal;
transforming, by the transmit end, the fourth signal back to a time domain by performing N-point GIDFT to obtain a non-cyclic prefix signal with N points;
performing, by the transmit end, phase shifting on the second signal based on cyclic prefix {n 2 , . . . , n 2 +K−1} to generate a fifth signal;
transforming, by the transmit end, the fifth signal to the frequency domain by performing K-point GDFT;
mapping, by the transmit end, the fifth signal onto the K subcarriers to obtain a sixth signal; and
transforming, by the transmit end, the sixth signal back to the time domain by performing N-point GIDFT to obtain a cyclic prefix signal with L points, wherein time corresponding to the L points is {ñ2, . . . , ñ2+L−1}, and
wherein L is a length of a cyclic prefix, N is a length of a non-cyclic prefix, and each of L and Nis an integer greater than or equal to 0.
6 . The method according to claim 4 , wherein the cyclic prefix signal and the non-cyclic prefix signal are continuous in time.
7 . The method according to claim 6 , wherein ñ 2 satisfies the following formula:
(
n
1
-
n
2
)
N
K
-
L
.
8 . A method for transmitting signals, comprising:
obtaining, by a receive end, a first signal on K subcarriers, wherein the first signal comprises a cyclic prefix signal, the cyclic prefix signal is a signal generated based on Z data signals and cyclic prefix time, a frequency occupied by the first signal is within a frequency range of frequency domain resources corresponding to the K subcarriers, and each of K and Z is an integer greater than or equal to 1; and
demodulating, by the receive end, the first signal by using the frequency range of the frequency domain resources corresponding to the K subcarriers as a sampling rate to obtain a data signal.
9 . The method according to claim 8 , wherein the first signal is an analog signal, the frequency of the first signal is within a first range, and the first range is
[
(
k
0
-
1
2
)
Δ
f
,
(
k
0
-
1
2
+
K
)
Δ
f
]
,
or the first range is
[
(
k
0
-
1
2
+
K
)
Δ
f
,
(
k
0
-
1
2
)
Δ
f
]
,
and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers, and Δf is a subcarrier width.
10 . The method according to claim 8 , wherein the first signal is a digital signal, the frequency of the first signal is within a second range, and the second range is [k 0 , k 0 +K−1], or the second range is [k 0 +K−1, k 0 ], and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers.
11 . A communication apparatus, comprising: at least one processor, and one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to:
perform linear frequency modulation on Z data signals within frequency domain resources corresponding to K subcarriers, to obtain a first signal, wherein the first signal comprises a cyclic prefix signal, the cyclic prefix signal is a signal generated based on the Z data signals and cyclic prefix time, a frequency occupied by the first signal is within a frequency range of the frequency domain resources corresponding to the K subcarriers, and a frequency occupied by each of Z data signals obtained through linear frequency modulation changes linearly with time, and wherein:
a z th data signal in the Z data signals corresponds to M z time segments, and slopes of linear changes of the M z time segments are the same;
when M z >1, a start frequency of an M z th time segment is a lowest frequency in the frequency range, and an end frequency of an (M z −1) th time segment is a highest frequency in the frequency range; or
when M z >1, a start frequency of an M z th time segment is a highest frequency in the frequency range, and an end frequency of an (M z −1) th segment is a lowest frequency in the frequency range; and
each of K, M z , and Z is an integer greater than or equal to 1, and z ranges from 1 to Z.
12 . The communication apparatus according to claim 11 , wherein the first signal is an analog signal, the frequency of the first signal is within a first range, and the first range is
[
(
k
0
-
1
2
)
Δ
f
,
(
k
0
-
1
2
+
K
)
Δ
f
]
,
or the first range is
[
(
k
0
-
1
2
+
K
)
Δ
f
,
(
k
0
-
1
2
)
Δ
f
]
,
and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers, k 0 is an integer, and Δf is a subcarrier width.
13 . The communication apparatus according to claim 11 , wherein the first signal is a digital signal, the frequency of the first signal is within a second range, and the second range is [k 0 , k 0 +K−1], or the second range is [k 0 +K−1, k 0 ], and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers, and k 0 is an integer.
14 . The communication apparatus according to claim 11 , wherein the first signal further comprises a non-cyclic prefix signal, and the non-cyclic prefix signal is a signal generated based on the Z data signals and non-cyclic prefix time.
15 . The communication apparatus according to claim 11 , wherein the one or more memories store the programming instructions for execution by the at least one processor to:
perform phase shifting on the Z data signals;
perform K-point general inverse discrete Fourier transform (GIDFT) on data signals obtained through phase shifting to generate a second signal;
perform phase shifting on the second signal based on non-cyclic prefix time {n 1 , . . . , n 1 +K−1} to generate a third signal;
transform the third signal to a frequency domain by performing K-point general discrete Fourier transform (GDFT);
map the third signal onto the K subcarriers to obtain a fourth signal;
transform the fourth signal back to a time domain by performing N-point GIDFT to obtain a non-cyclic prefix signal with N points;
perform phase shifting on the second signal based on cyclic prefix time {n 2 , . . . , n 2 +K−1} to generate a fifth signal,
transform the fifth signal to the frequency domain by performing K-point GDFT;
map the fifth signal onto the K subcarriers to obtain a sixth signal; and
transform the sixth signal back to the time domain by performing N-point GIDFT to obtain a cyclic prefix signal with L points, wherein time corresponding to the L points is {ñ 2 , . . . , ñ 2 +L−1}, and
wherein L is a length of a cyclic prefix, N is a length of a non-cyclic prefix, and each of L and N is an integer greater than or equal to 0.
16 . The communication apparatus according to claim 14 , wherein the cyclic prefix signal and the non-cyclic prefix signal are continuous in time.
17 . The communication apparatus according to claim 16 , wherein ñ 2 satisfies the following formula:
(
n
1
-
n
2
)
N
K
-
L
.
18 . A communication apparatus, comprising: at least one processor, and one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to:
obtain a first signal on K subcarriers, wherein the first signal comprises a cyclic prefix signal, the cyclic prefix signal is a signal generated based on Z data signals and cyclic prefix time, a frequency occupied by the first signal is within a frequency range of frequency domain resources corresponding to the K subcarriers, and each of K and Z is an integer greater than or equal to 1; and
demodulate the first signal by using the frequency range of the frequency domain resources corresponding to the K subcarriers as a sampling rate to obtain a data signal.
19 . The communication apparatus according to claim 18 , wherein the first signal is an analog signal, the frequency of the first signal is within a first range, and the first range is
[
(
k
0
-
1
2
)
Δ
f
,
(
k
0
-
1
2
+
K
)
Δ
f
]
,
or the first range is
[
(
k
0
-
1
2
+
K
)
Δ
f
,
(
k
0
-
1
2
)
Δ
f
]
,
and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers, and Δf s a subcarrier width.
20 . The communication apparatus according to claim 18 , wherein the first signal is a digital signal, the frequency of the first signal is within a second range, and the second range is [k 0 , k 0 +K−1], or the second range is [k 0 +K−1, k 0 ], and wherein
k 0 is a subcarrier index corresponding to a subcarrier with a lowest frequency in the K subcarriers.