Method and device for detecting primary synchronization signal and generating sequence in long term evolution (LTE) system
View Patent ↗The present invention discloses a method and a device for detecting a primary synchronization signal and generating a sequence in a LTE system, so as to solve the problem that the overhead for 3GPP LTE system to store a local primary synchronization sequence is too much during the initial cell search process. The method for detecting a primary synchronization signal includes: directly generating a local primary synchronization signal sequence with equal amplitude in the time domain as a matched filter; performing a front-end processing for a received signal; performing the matched filtering between the received signal after the front-end processing and the local primary synchronization signal sequence; judging the output amplitude of the signal sequence obtained after the matched filtering; and then obtaining a judgment result of the local primary synchronization signal sequence.
1. A method for detecting a primary synchronization signal in a Long Term Evolution (LTE) system, comprising:
directly generating a local primary synchronization signal sequence with equal amplitude in time domain as a matched filter; and
performing a front-end processing for a received signal; performing matched filtering between the received signal after the front-end processing and the local primary synchronization signal sequence; judging output amplitude of the signal sequence obtained after the matched filtering; and then obtaining a judgment result of the local primary synchronization signal sequence;
wherein the local primary synchronization signal sequence is generated by the following formula:
x
u
(
n
)
=
ⅇ
-
j
2
π
31
n
+
θ
(
u
)
63
ⅇ
-
j
π
u
(
-
n
×
u
-
1
)
(
-
n
×
u
-
1
+
1
)
63
,
n
=
0
,
1
,
…
,
62
wherein, θ(u)=4.75, −27.25, 27.25, when u=25, 29, 34; u −1 =28, 50, 13, and u −1 refers to a multiplicative inverse element of u mod N ZC , N ZC =63.
2. The method of claim 1 , wherein,
the front-end processing comprises an analog-digital conversion, an automatic gain control, a low-pass filtering and rate transform; and a sampling rate of the received signal after the front-end processing is 0.96 MHz.
3. The method of claim 1 , further comprising:
splitting the local primary synchronization signal sequence to be in M channels after generating the local primary synchronization signal sequence:
the local primary synchronization signal sequence of an i th channel is x u *(n)e j2πξ i n/63 , wherein, n=0, 1, . . . , 62, ξ i is a preset normalized frequency deviation factor of the i th channel.
4. The method of claim 1 , wherein, the step of judging output amplitude of the signal sequence obtained after the matched filtering and obtaining a judgment result of the local primary synchronization signal comprises:
judging the output amplitude output from the matched filter, and selecting a sequence number corresponding to a sequence meeting a condition of a preset amplitude peak to be taken as a sequence index of the primary synchronization signal sequence of a transmitted signal;
obtaining by calculation a rough estimate of a channel carrier frequency deviation: Δ{circumflex over (f)}=−ξ i ×15000 MHz according to a normalized frequency deviation factor of the sequence meeting the condition of the preset amplitude peak.
5. The method of claim 1 , further comprising:
before the judgment, performing a plurality of merging and averaging of 5 ms radio half-frames on the signal sequence obtained after the matched filtering, and then judging the result of merging and averaging of the radio half-frames.
6. A method for generating a primary synchronization signal sequence in a Long Term Evolution (LTE) system, comprising:
directly generating a local primary synchronization signal sequence with equal amplitude in time domain;
wherein the local primary synchronization signal sequence with equal amplitude is directly generated in the time domain by the following formula:
x
u
(
n
)
=
ⅇ
-
j
2
π
31
n
+
θ
(
u
)
63
ⅇ
-
j
π
u
(
-
n
×
u
-
1
)
(
-
n
×
u
-
1
+
1
)
63
,
n
=
0
,
1
,
…
,
62
;
wherein, θ(u)=4.75, −27.25, 27.25, when u=25, 29, 34; u −1 =28, 50, 13, and u −1 refers to a multiplicative inverse element of u mod N ZC , N ZC =63.
7. A device for detecting a primary synchronization signal in a Long Term Evolution (LTE) system, comprising at least one processor executing a local sequence generation unit, a front-end processing unit, a filtering unit and a judging unit, wherein:
the local sequence generation unit is configured to generate a local primary synchronization signal sequence with equal amplitude in time domain as a matched filter directly;
the front-end processing unit is configured to perform a front-end processing on a received signal, and to transmit the received signal after being processed to the filtering unit;
the filtering unit is configured to perform a matched filtering between the received signal after the front-end processing and the local primary synchronization signal sequence, and to transmit the signal sequence obtained after the matched filtering to the judging unit;
the judging unit is configured to judge output amplitude of the signal sequence obtained after the matched filtering, so as to obtain a judgment result of the primary synchronization signal sequence;
wherein the local sequence generation unit is configured to generate the local primary synchronization signal sequence by the following formula:
x
u
(
n
)
=
ⅇ
-
j
2
π
31
n
+
θ
(
u
)
63
ⅇ
-
j
π
u
(
-
n
×
u
-
1
)
(
-
n
×
u
-
1
+
1
)
63
,
n
=
0
,
1
,
…
,
62
;
wherein, θ(u)=4.75, −27.25, 27.25, when u=25, 29, 34; u −1 =28, 50, 13, and u −1 refers to a multiplicative inverse element of u mod N ZC , N ZC =63.
8. The device of claim 7 , wherein,
the front-end processing unit is configured to perform the following front-end processing on the received signal: an analog-digital conversion, an automatic gain control, a low-pass filtering and rate transform;
a sampling rate of the received signal after the front-end processing is 0.96 MHz.
9. The device of claim 7 , wherein,
the local sequence generation unit is further configured to split the local primary synchronization signal sequence to be in M channels after generating the local primary synchronization signal sequence: the local primary synchronization signal sequence of an i th channel being x u *(n)e j2πξ i n/63 , wherein, n=0, 1, . . . , 62, ξ i is a preset normalized frequency deviation factor of the i th channel.
10. The device of claim 9 , wherein,
the device further comprises a half-frame merging unit, the half-frame merging unit is configured: to receive the signal sequence sent by the matched filtering unit after the matched filtering, to perform a plurality of merging and averaging of 5 ms radio half-frames on the signal sequence obtained after the matched filtering, and to transmit the result of merging and averaging of the radio half-frames to the judgment unit to be judged.
11. The method of claim 4 , further comprising:
before the judgment, performing a plurality of merging and averaging of 5 ms radio half-frames on the signal sequence obtained after the matched filtering, and then judging the result of merging and averaging of the radio half-frames.