CN102158447A - Scrambling code number detection method and device - Google Patents
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Abstract
The invention discloses a scrambling code number detection method, which comprises the following steps of: descrambling orthogonal frequency division multiplexing (OFDM) effective sub-carriers obtained by OFDM symbols received in a current timeslot by adopting each scrambling code respectively, and extracting continuous pilot sub-carriers or discrete pilot sub-carriers corresponding to each scrambling code from each descrambled OFDM effective sub-carrier respectively; and determining a scrambling code number of the current timeslot by using the power of the continuous pilot sub-carriers or discrete pilot sub-carriers corresponding to each scrambling code to finish the detection of the scrambling code number. The invention also discloses a scrambling code number detection device. By the method and the device, the problem that a receiver cannot rapidly and effectively obtain the scrambling code number of the current timeslot is effectively solved, so synchronous signal transmission between the receiver and a transmitter can be ensured to be finished smoothly.
Description
Technical Field
The present invention relates to the field of orthogonal frequency division multiplexing communication, and in particular, to a scrambling code number detection method and apparatus.
Background
The mobile phone television is a service for watching television by using a mobile phone with a video support function. At present, there are three main ways to implement mobile phone television service:
(1) the implementation technology based on the mobile network comprises the following steps: at present, mobile television services launched by american and chinese operators are mainly implemented by means of existing mobile networks, for example, both china mobile and china unicom have launched mobile television services by using mobile streaming media technology based on their GPRS networks and CDMA1X networks, respectively.
(2) The realization technology based on the satellite is as follows: this kind of technology provides downlink transmission through a satellite to realize mobile phone television services in a broadcast mode, and users can realize the reception of multimedia data by integrating a module for directly receiving satellite signals on a mobile phone terminal; typical technologies include S-DVB in Europe and S-DMB in Japanese and Korean, etc.
(3) The implementation technology based on the ground digital broadcasting network comprises the following steps: such techniques are mainly generated for terrestrial digital broadcast television, and the frequencies used are generally broadcast television bands.
The China Mobile Multimedia Broadcasting (CMMB) standard is proposed by the national broadcast television bureau and promulgated as an industry standard in 2006, 10 months. The CMMB adopts a technical system of combining an S-waveband high-power satellite with a ground same-frequency supplementary network, combines unidirectional broadcasting and bidirectional interaction, realizes national all-in-one coverage and national roaming, and is suitable for a broadcasting system which has a frequency range of 30 Mhz-3000 Mhz and transmits multimedia signals such as television, broadcasting, data information and the like through satellite or ground wireless.
According to the first part of GY/T220 Mobile multimedia broadcasting: a broadcast channel frame structure, channel coding and modulation rules, a transmitter of a broadcast system performs forward error correction coding, interleaving and constellation mapping on broadcasted service data, then multiplexes the service data with a discrete pilot Frequency and a continuous pilot Frequency to obtain an Orthogonal Frequency Division Multiplexing (OFDM) effective subcarrier, scrambles the obtained OFDM effective subcarrier by eight scrambling codes of 0 to 7 defined in a protocol, maps the scrambled OFDM effective subcarrier into OFDM symbols by Inverse Fast Fourier Transform (IFFT), and finally divides a transmission signal composed of the OFDM symbols into 40 time slots by taking one frame as a period unit and transmits the OFDM symbols to a receiver. Scrambling codes adopted when all OFDM symbols in each time slot are scrambled are the same, for example, a time slot 0 fixedly adopts a number 0 scrambling code; the receiver of the terminal receives the sending signal, needs to demodulate the OFDM symbol therein, and obtains the scrambling code adopted during scrambling to complete descrambling, thereby finally obtaining the service data sent by the broadcasting system, and ensuring that the data transmission between the terminal and the broadcasting system is completely synchronous.
However, in the prior art, since the receiver of the terminal cannot know the scrambling code number used in the current time slot, when demodulating the OFDM symbol in the time slot, it needs to detect the scrambling code number of the time slot first to complete corresponding descrambling, and finally, synchronously receive the service data sent by the broadcasting system.
Disclosure of Invention
In view of the above, the main objective of the present invention is to provide a method and an apparatus for detecting a scrambling code number, so as to solve the problem that a receiver of a terminal cannot determine the scrambling code number used in each timeslot, so that synchronous reception of service data is affected.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the invention provides a scrambling code number detection method, which comprises the following steps: according to the OFDM symbol received by the current time slot, a receiver of the terminal obtains an OFDM effective subcarrier; descrambling the obtained OFDM effective subcarriers by using the scrambling codes defined by the protocol, and extracting continuous pilot subcarriers or discrete pilot subcarriers corresponding to the scrambling codes from the descrambled OFDM effective subcarriers respectively; and determining the scrambling code number of the current time slot according to the power of the continuous pilot frequency subcarrier or the scattered pilot frequency subcarrier corresponding to each extracted scrambling code, and finishing the detection of the scrambling code number.
In the above scheme, the process of determining the scrambling code number of the current timeslot specifically includes: calculating the power of continuous pilot frequency sub-carriers or discrete pilot frequency sub-carriers corresponding to each scrambling code; searching the maximum power value in the calculated power corresponding to each scrambling code; and obtaining a scrambling code corresponding to the found maximum power value, and taking the scrambling code number of the scrambling code as the scrambling code number of the current time slot.
In the above scheme, the process of calculating the power of a continuous pilot subcarrier or a discrete pilot subcarrier corresponding to one scrambling code specifically includes: and carrying out conjugate coherent operation, accumulation and power operation on the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code in sequence to obtain the power of the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code.
In the above scheme, the process of calculating the power of a continuous pilot subcarrier or a discrete pilot subcarrier corresponding to one scrambling code specifically includes: and coherent accumulation is carried out on continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers corresponding to the scrambling codes, power operation is carried out on the result of the coherent accumulation, and finally non-coherent accumulation is carried out on the result of the power operation to obtain the power of the continuous pilot frequency sub-carriers or the scattered pilot frequency sub-carriers corresponding to the scrambling codes.
In the above scheme, the extracting continuous pilot subcarriers or scattered pilot subcarriers from each descrambled OFDM effective subcarrier specifically includes: and respectively extracting partial or all continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers from each OFDM effective sub-carrier after descrambling to obtain continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers corresponding to each scrambling code.
In the above scheme, the process of obtaining the OFDM effective subcarriers specifically includes: and the receiver of the terminal performs fast Fourier transform operation on the OFDM symbol received by the current time slot to obtain the effective subcarrier of the OFDM.
The invention also provides a scrambling code number detection device, which comprises: receiving unit, acquisition unit, descrambling unit, extraction element, determining unit, wherein: a receiving unit, configured to receive an OFDM symbol of a current slot; an obtaining unit, configured to obtain an OFDM effective subcarrier according to the OFDM symbol received by the receiving unit; a descrambling unit, configured to descramble the OFDM effective subcarriers obtained by the obtaining unit by using each scrambling code defined by a protocol; an extracting unit, configured to extract continuous pilot subcarriers or discrete pilot subcarriers corresponding to each scrambling code from each OFDM effective subcarrier obtained by the descrambling unit, respectively; and the determining unit is used for determining the scrambling code number of the current time slot according to the power of the continuous pilot frequency subcarrier or the discrete pilot frequency subcarrier corresponding to each scrambling code extracted by the extracting unit.
In the foregoing scheme, the obtaining unit is specifically configured to perform fast fourier transform operation on an OFDM symbol received by the receiving unit in a current time slot, so as to obtain an OFDM effective subcarrier.
In the foregoing solution, the extracting unit is specifically configured to extract, from each OFDM effective subcarrier obtained by the descrambling unit, a part or all of continuous pilot subcarriers or scattered pilot subcarriers, respectively, to obtain continuous pilot subcarriers or scattered pilot subcarriers corresponding to each scrambling code.
In the foregoing solution, the determining unit specifically includes: the device comprises a calculation module, a search module and a scrambling code number determination module; the calculating module is used for calculating the power of the continuous pilot frequency sub-carrier or the scattered pilot frequency sub-carrier corresponding to each scrambling code extracted by the extracting unit; the searching module is used for searching the maximum power value in the power which is obtained by the calculating module and corresponds to each scrambling code; and the scrambling code number determining module is used for obtaining the scrambling code corresponding to the maximum power value found by the searching module, and the scrambling code number of the scrambling code is the scrambling code number of the current time slot.
The invention adopts each scrambling code to descramble the OFDM effective sub-carrier obtained by the OFDM symbol received by the current time slot, extracts the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to different scrambling codes from each descrambled OFDM effective sub-carrier, determines the scrambling code number of the current time slot according to the power of each extracted continuous pilot frequency sub-carrier or discrete pilot frequency sub-carrier, and completes the detection of the scrambling code number of the current time slot, thereby effectively solving the problem that the receiver can not quickly and effectively obtain the scrambling code number of the current time slot, and ensuring the smooth completion of the signal synchronous transmission between the receiver and the transmitter.
Drawings
FIG. 1 is a schematic diagram of a flow chart of a scrambling code number detection method according to the present invention;
FIG. 2 is a schematic diagram of an OFDM effective subcarrier composition of an OFDM symbol in a time slot of CMMB;
FIG. 3 is a schematic diagram of the structure of the scrambling code number detecting apparatus according to the present invention;
FIG. 4 is a schematic flow chart of the detection of the scrambling code number of the CMMB system mobile TV terminal by the invention.
Detailed Description
The scrambling code number detection method of the invention adopts each scrambling code to descramble the OFDM effective sub-carrier obtained by the OFDM symbol of the current time slot respectively, and extracts the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier from each OFDM effective sub-carrier after descrambling to complete the detection of the scrambling code number.
Referring to fig. 1, the scrambling code number detection method of the present invention mainly includes the following steps:
step 101: according to the OFDM symbol received by the current time slot, a receiver of the terminal obtains an OFDM effective subcarrier;
specifically, the OFDM effective subcarriers can be obtained by performing FFT operation on the OFDM symbol received at the current time slot;
step 102: descrambling the obtained OFDM subcarriers by using scrambling codes defined by a protocol respectively, and extracting continuous pilot subcarriers or discrete pilot subcarriers corresponding to the scrambling codes from the descrambled OFDM effective subcarriers respectively;
specifically, eight scrambling codes No. 0-7 are defined in the protocol in common, so in practical application, the eight scrambling codes specified in the protocol can be used to descramble the obtained OFDM effective subcarriers respectively, and part or all of continuous pilot subcarriers or scattered pilot subcarriers are extracted from the descrambled OFDM effective subcarriers corresponding to the eight scrambling codes respectively to obtain continuous pilot subcarriers or scattered pilot subcarriers corresponding to the eight scrambling codes.
Here, the OFDM active sub-carriers include continuous pilot sub-carriers, scattered pilot sub-carriers, and a service data stream to be transmitted, where the continuous pilot sub-carriers and the scattered pilot sub-carriers are obtained through protocol negotiation before the broadcast system performs service data transmission with the terminal, and are already stored in the broadcast system and the terminal.
The scattered pilot frequency sub-carrier does not carry any information and is mainly used for assisting a receiver to carry out channel estimation, coherent detection and demodulation; the transmission indication information of the broadcasting system is carried on part of the continuous pilot subcarriers.
For example, refer to the schematic diagram of OFDM effective subcarrier composition of OFDM symbols in one slot in CMMB of fig. 2, wherein the vertical axis represents 53 OFDM symbols in one slot; the horizontal axis represents OFDM effective subcarriers corresponding to each OFDM symbol, and the OFDM effective subcarriers comprise continuous pilot subcarriers, scattered pilot subcarriers and data to be transmitted; the continual pilots are indicated by diagonal padding, the scattered pilots by black padding, and the remaining empty padding indicating the data to be transmitted.
Step 103: and determining the scrambling code number of the current time slot according to the power of the continuous pilot frequency subcarrier or the scattered pilot frequency subcarrier corresponding to each extracted scrambling code, and finishing the detection of the scrambling code number.
Specifically, the process of determining the scrambling code number of the current timeslot may be: firstly, calculating the power of continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers corresponding to each scrambling code; secondly, searching a maximum power value in the calculated power corresponding to each scrambling code; and finally, obtaining the scrambling code corresponding to the found maximum power value, and taking the scrambling code number of the scrambling code as the scrambling code number of the current time slot to finish the determination of the scrambling code number of the current time slot.
The process of calculating the power of the continuous pilot subcarriers or the scattered pilot subcarriers corresponding to any scrambling code may specifically be: carrying out conjugate coherent operation, accumulation and power operation on the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code in sequence to obtain the power of the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code;
alternatively, it is also possible: and carrying out coherent accumulation on the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code, then carrying out power operation on the result of the coherent accumulation, and finally carrying out non-coherent accumulation on the result of the power operation to obtain the power of the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier of the scrambling code.
Referring to fig. 3, a scrambling code number detection apparatus of the present invention mainly includes: a receiving unit 31, an obtaining unit 32, a descrambling unit 33, an extracting unit 34, and a determining unit 35, wherein:
a receiving unit 31, configured to receive an OFDM symbol of a current slot;
an obtaining unit 32, configured to obtain an OFDM effective subcarrier according to the OFDM symbol received by the receiving unit 31;
a descrambling unit 33, configured to descramble the OFDM effective subcarriers obtained by the obtaining unit 32 by using each scrambling code defined by a protocol;
an extracting unit 34, configured to extract continuous pilot subcarriers or scattered pilot subcarriers corresponding to each scrambling code from each OFDM effective subcarrier obtained by the descrambling unit 33;
a determining unit 35, configured to determine the scrambling code number of the current time slot according to the power of the continuous pilot subcarriers or the scattered pilot subcarriers corresponding to each scrambling code extracted by the extracting unit 34.
The obtaining unit 32 may specifically perform fast fourier transform operation on the OFDM symbol received by the receiving unit 31 in the current time slot to obtain an OFDM effective subcarrier; the extracting unit 34 may specifically extract part or all of the continuous pilot subcarriers or the scattered pilot subcarriers from the OFDM effective subcarriers obtained by the descrambling unit 33, respectively, to obtain continuous pilot subcarriers or scattered pilot subcarriers corresponding to each scrambling code.
The determining unit 35 may specifically include: a calculation module 351, a search module 352, and a scrambling code number determination module 353, wherein:
a calculating module 351, configured to calculate power of a continuous pilot subcarrier or a scattered pilot subcarrier corresponding to each scrambling code extracted by the extracting unit 34;
a searching module 352, configured to search a maximum power value from the powers corresponding to the scrambling codes obtained by the calculating module 351;
and a scrambling code number determining module 353, configured to obtain a scrambling code corresponding to the maximum power value found by the searching module 352, and use the scrambling code number of the scrambling code as the scrambling code number of the current time slot.
For any scrambling code, the calculating module 351 may specifically obtain the power of the continuous pilot subcarriers or the scattered pilot subcarriers corresponding to the scrambling code through the following process:
sequentially performing conjugate coherent operation, accumulation and power operation on the continuous pilot subcarriers or the discrete pilot subcarriers corresponding to the scrambling codes extracted by the extraction unit 34 to obtain the power of the continuous pilot subcarriers or the discrete pilot subcarriers corresponding to the scrambling codes;
or, coherent accumulation is performed on the continuous pilot subcarriers or the scattered pilot subcarriers corresponding to the scrambling codes extracted by the extraction unit 34, then power operation is performed on the coherent accumulation result, and finally non-coherent accumulation is performed on the power operation result to obtain the power of the continuous pilot subcarriers or the scattered pilot subcarriers corresponding to the scrambling codes.
Here, the scrambling code number detection device may be provided in a receiver of the terminal, and may detect the scrambling code number of the OFDM symbol in each slot.
The following describes a specific implementation manner of the present invention applied to scrambling code number detection of a mobile phone television terminal of the CMMB system in detail.
Referring to fig. 4, the scrambling code number detection of the CMMB-system mobile television terminal is realized by the present invention, and the specific flow is as follows:
step 401: respectively carrying out FFT operation with 4096 lengths on 53 OFDM symbols received by the current time slot, and extracting 3076 OFDM effective subcarriers a from the FFT operation resulti，j；
Wherein i is an OFDM symbol index and satisfies the condition that i is more than or equal to 0 and less than or equal to 52; j is an OFDM effective subcarrier index and satisfies j more than or equal to 0 and less than or equal to 3075; the number of OFDM symbols received in a time slot is 53, where the OFDM symbols participating in the FFT operation may be a part or all of the 53 OFDM symbols, and the specific number may range from 2 to 53.
Step 402: setting the scrambling code number m of the current scrambling code as zero;
step 403: scrambling sequence s using the current scrambling code according to equation (1)i，jFor OFDM effective sub-carrier ai，jDescrambling is carried out to obtain the OFDM effective subcarrier b after descramblingi，j；
bi，j＝ai，j×conj(si，j) (1)
Wherein, conj (·) is conjugate operation, i is OFDM symbol index, satisfies 0 ≤ i ≤ 52; j is an OFDM effective subcarrier index and satisfies that j is more than or equal to 0 and less than or equal to 3075.
Here, each scrambling code is preset with a corresponding scrambling code sequence, and scrambling and descrambling of the OFDM effective subcarriers need to be completed by the scrambling code sequence of each scrambling code.
Step 404: from the descrambled OFDM effective sub-carriers bi，jIn the method, 82 continuous pilot frequency subcarriers c are extractedi，k；
Wherein i is an OFDM symbol index and satisfies the condition that i is more than or equal to 0 and less than or equal to 52; k is the index of the extracted continuous pilot frequency subcarrier and satisfies that k is more than or equal to 0 and less than or equal to 81.
Here, the number of extracted continuous pilot subcarriers may be determined according to actual application needs. Because of the OFDM effective subcarrier b after descramblingi，jA total of 82 continual pilot subcarriers are included, and thus the number of extracted continual pilot subcarriers ranges from 1 to 82.
Step 405: for the extracted continuous pilot frequency subcarrier ci，kCarrying out conjugate coherent operation on continuous pilot subcarriers with the same continuous pilot subcarrier index and adjacent front and back continuous pilot subcarrier indexes of the middle OFDM symbol index according to a formula (2) to obtain a continuous pilot subcarrier d subjected to conjugate operationi，k；
di，k＝ci-1，k×conj(ci，k) (2)
Wherein i is an OFDM symbol index and satisfies the condition that i is more than or equal to 0 and less than or equal to 52; k is the index of the extracted continuous pilot frequency subcarrier and satisfies that k is more than or equal to 0 and less than or equal to 81.
Step 406: according to the formula (3), the continuous pilot frequency subcarrier d after the conjugate operationi，kAccumulating to obtain an accumulation result e of continuous pilot frequency sub-carriers corresponding to the current scrambling codes;
wherein i is an OFDM symbol index and satisfies the condition that i is more than or equal to 0 and less than or equal to 52; k is the index of the extracted continuous pilot frequency subcarrier and satisfies that k is more than or equal to 0 and less than or equal to 81.
Step 407: performing power operation on the accumulation result e according to a formula (4) to obtain the power f of the continuous pilot frequency subcarrier corresponding to the current scrambling code mm；
fm＝abs(e)·abs(e) (4)
Wherein m is the scrambling code number of the current scrambling code.
Step 408-409: judging whether the current scrambling code is the last scrambling code, namely judging whether the scrambling code number m of the current scrambling code meets the formula (5),
m＞7 (5)
if not, changing the next scrambling code to the current scrambling code, namely m is m +1, and returning to the step 403; otherwise, step 410 is continued.
Step 410: the power f of the continuous pilot frequency sub-carrier corresponding to each scrambling code obtained in the above-mentioned step 402-409mM is more than or equal to 0 and less than or equal to 7, and the maximum power value f is searchednWherein f isnSatisfies formula (6):
fn＝max(fm)，(0≤m≤7) (6)
the found power fnThe corresponding scrambling code number n is the scrambling code number corresponding to the current time slot, and the detection process of the scrambling code number of the current time slot is completed.
The process of calculating the power of the continuous pilot subcarriers corresponding to each scrambling code, which is implemented in the above-mentioned step 405-407, can also be implemented by the following procedures:
firstly: coherent accumulation is carried out on the continuous pilot frequency sub-carriers extracted in the step 404 according to a formula (7) to obtain phasesDry sum result gkCoherent accumulation takes OFDM symbol index i as unit length;
wherein, in the embodiment, the OFDM symbol index i satisfies 0 ≦ i ≦ 52.
Specifically, the value range of i is determined by the number of the selected OFDM symbols.
Secondly, the method comprises the following steps: the coherent accumulation result g obtained can be compared according to equation (8)kCalculating power to obtain gkPower h ofm；
hk，m＝abs(g)·abs(g) (8)
And finally: the coherent accumulation results g obtained can be compared according to the formula (9)kPower h ofk，mPerforming incoherent accumulation, and obtaining the power f of the continuous pilot frequency subcarrier corresponding to the current scrambling code m by taking the index k of the continuous pilot frequency subcarrier as the unit lengthm；
In the embodiment, the continuous pilot subcarrier index k satisfies 0 ≦ k ≦ 81.
Specifically, the value range of k is determined by the number of extracted continuous pilot subcarriers.
It should be noted that, in the above embodiment, the detection of the current timeslot scrambling code number can also be achieved by extracting the scattered pilot subcarriers from the OFDM subcarriers, and a specific implementation procedure is similar to the procedure in the above embodiment, except that the number range of the extracted scattered pilot subcarriers is 0 to 384, which can be directly obtained by a person skilled in the art from the above procedure, and therefore, details are not described here again.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.
Claims (10)
1. A method for scrambling code number detection, the method comprising:
according to the OFDM symbol received by the current time slot, a receiver of the terminal obtains an OFDM effective subcarrier;
descrambling the obtained OFDM effective subcarriers by using the scrambling codes defined by the protocol, and extracting continuous pilot subcarriers or discrete pilot subcarriers corresponding to the scrambling codes from the descrambled OFDM effective subcarriers respectively;
and determining the scrambling code number of the current time slot according to the power of the continuous pilot frequency subcarrier or the scattered pilot frequency subcarrier corresponding to each extracted scrambling code, and finishing the detection of the scrambling code number.
2. The method for detecting a scrambling code number according to claim 1, wherein the process for determining the scrambling code number of the current timeslot specifically comprises:
calculating the power of continuous pilot frequency sub-carriers or discrete pilot frequency sub-carriers corresponding to each scrambling code; searching the maximum power value in the calculated power corresponding to each scrambling code; and obtaining a scrambling code corresponding to the found maximum power value, and taking the scrambling code number of the scrambling code as the scrambling code number of the current time slot.
3. The method for detecting a scrambling code number according to claim 2, wherein the process of calculating the power of a continuous pilot subcarrier or a scattered pilot subcarrier corresponding to a scrambling code specifically comprises:
and carrying out conjugate coherent operation, accumulation and power operation on the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code in sequence to obtain the power of the continuous pilot frequency sub-carrier or the discrete pilot frequency sub-carrier corresponding to the scrambling code.
4. The method for detecting a scrambling code number according to claim 2, wherein the process of calculating the power of a continuous pilot subcarrier or a scattered pilot subcarrier corresponding to a scrambling code specifically comprises:
and coherent accumulation is carried out on continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers corresponding to the scrambling codes, power operation is carried out on the result of the coherent accumulation, and finally non-coherent accumulation is carried out on the result of the power operation to obtain the power of the continuous pilot frequency sub-carriers or the scattered pilot frequency sub-carriers corresponding to the scrambling codes.
5. The method for detecting a scrambling code number according to any one of claims 1 to 4, wherein the extracting continuous pilot subcarriers or scattered pilot subcarriers from each OFDM effective subcarrier after descrambling specifically comprises:
and respectively extracting partial or all continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers from each OFDM effective sub-carrier after descrambling to obtain continuous pilot frequency sub-carriers or scattered pilot frequency sub-carriers corresponding to each scrambling code.
6. The method for detecting a scrambling code number according to claim 1, wherein the process for obtaining OFDM effective subcarriers specifically comprises:
and the receiver of the terminal performs fast Fourier transform operation on the OFDM symbol received by the current time slot to obtain the effective subcarrier of the OFDM.
7. An apparatus for detecting a scrambling code number, the apparatus comprising: receiving unit, acquisition unit, descrambling unit, extraction element, determining unit, wherein:
a receiving unit, configured to receive an OFDM symbol of a current slot;
an obtaining unit, configured to obtain an OFDM effective subcarrier according to the OFDM symbol received by the receiving unit;
a descrambling unit, configured to descramble the OFDM effective subcarriers obtained by the obtaining unit by using each scrambling code defined by a protocol;
an extracting unit, configured to extract continuous pilot subcarriers or discrete pilot subcarriers corresponding to each scrambling code from each OFDM effective subcarrier obtained by the descrambling unit, respectively;
and the determining unit is used for determining the scrambling code number of the current time slot according to the power of the continuous pilot frequency subcarrier or the discrete pilot frequency subcarrier corresponding to each scrambling code extracted by the extracting unit.
8. The scrambling code number detecting device according to claim 7, wherein the obtaining unit is specifically configured to perform fast fourier transform operation on the OFDM symbol received by the receiving unit in the current time slot to obtain the OFDM effective subcarriers.
9. The scrambling code number detecting device of claim 7, wherein the extracting unit is specifically configured to extract part or all of the continuous pilot subcarriers or the scattered pilot subcarriers from the OFDM effective subcarriers obtained by the descrambling unit, respectively, so as to obtain continuous pilot subcarriers or scattered pilot subcarriers corresponding to the scrambling codes.
10. The scrambling code number detecting device according to claim 7, wherein the determining unit specifically includes: the device comprises a calculation module, a search module and a scrambling code number determination module; wherein,
a calculating module, configured to calculate power of continuous pilot subcarriers or discrete pilot subcarriers corresponding to each scrambling code extracted by the extracting unit;
the searching module is used for searching the maximum power value in the power which is obtained by the calculating module and corresponds to each scrambling code;
and the scrambling code number determining module is used for obtaining the scrambling code corresponding to the maximum power value found by the searching module, and the scrambling code number of the scrambling code is the scrambling code number of the current time slot.
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Application publication date: 20110817 |