CN111740937A - Synchronization method, device, equipment and storage medium of wireless broadband communication system - Google Patents
Synchronization method, device, equipment and storage medium of wireless broadband communication system Download PDFInfo
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Abstract
The invention discloses a synchronization method, a device, equipment and a storage medium of a wireless broadband communication system; in the scheme, when the wireless broadband communication system realizes the dynamic reconstruction of the frequency spectrum, firstly, a subchannel for transmitting data needs to be selected, wherein the subchannel comprises a plurality of subcarriers, an actual pseudo-random sequence is sent on even subcarriers of the subchannel, and zeros are sent on odd subcarriers, so that the synchronization sequence of the time domain has conjugate central symmetry and excellent synchronization performance; therefore, when the wireless broadband communication system in the scheme realizes dynamic reconstruction of the frequency spectrum, even if only a middle molecular channel is selected and a sequence is transmitted on a subcarrier contained by the middle molecular channel according to the rule, a time domain sequence corresponding to a frequency domain sequence still meets the conjugate central symmetry property, and further synchronous operation can be executed; in addition, the timing function calculation method disclosed by the invention can greatly reduce the calculation complexity and reduce the consumption of hardware resources.
Description
Technical Field
The present invention relates to the field of mobile communication system technology, and more particularly, to a synchronization method, apparatus, device and storage medium for a wireless broadband communication system.
Background
In recent years, both civil communication and military communication have made increasing demands on the transmission capacity of the system, and the theory and technology of broadband wireless communication have been advanced. However, as the number of electronic devices increases, the electromagnetic environment faced by the communication device becomes more and more complex, and therefore, cognitive radio technology is proposed to solve the problem of reliable communication in the complex electromagnetic environment. The basic idea is to select an available frequency spectrum for communication by sensing the electromagnetic environment faced by the communication equipment, and to achieve the purpose, firstly, a broadband communication waveform with configurable parameters needs to be constructed, and dynamic reconstruction of the waveform frequency spectrum is supported by configuring waveform parameters, so that dynamic utilization and release of frequency spectrum resources are achieved.
The basic principle of Orthogonal Frequency Division Multiplexing (OFDM) is to divide a channel into a plurality of subcarriers, convert a high-speed data signal into parallel low-speed sub-data streams, and modulate the parallel low-speed sub-data streams onto each subchannel for transmission. According to the basic principle of the OFDM system, whether the subcarriers transmit information or not can be controlled, so that the dynamic arrangement of the waveform frequency spectrum can be flexibly and conveniently realized, and further, the dynamic calling and the release of frequency spectrum resources are realized. Considering that interference or available spectrum resources in an actual electromagnetic environment cannot realize dynamic requisition and release by using subcarriers as basic units, because a guard interval is considered to reduce adjacent channel interference, a subchannel is generally formed by a plurality of subcarriers, and dynamic frequency spectrum requisition and release are realized by using the subchannel as a basic unit. Referring to fig. 1, a model for dividing a subchannel of an OFDM waveform channel bandwidth in a conventional scheme is shown in fig. 1, and a bandwidth of a waveform channel of a broadband dynamic spectrum access communication system of an OFDM system is assumed to be
specifically, the mutual independence between the sub-channels means that each sub-channel adopts an independent control channel to transmit control information, see fig. 2, and is a schematic design diagram of an independent control channel in the existing scheme, as shown in fig. 2, it can be seen that the method is flexible and convenient, is convenient to implement, has good backward compatibility, and can support flexible arrangement of the sub-channels and flexible reconstruction of waveforms.
Referring to fig. 3, a sub-channel division model for the rf front-end working band is assumed that the rf front-end bandwidth of the hardware platform (communication device) is
The lowest operating frequency is
The highest working frequency is
This means that signals in the operating frequency range of the rf front end can be normally received or transmitted by configuring appropriate parameters such as the operating center frequency point and the bandwidth of the analog filter. The sub-channel bandwidth of the waveform of the OFDM system is taken as a basic unit, and the bandwidth of the radio frequency front end is divided into
Sub-channels, numbering sub-channels as
Assuming that the central working frequency point of the radio frequency front end is
Then the center frequency point of each sub-channel is
. The method for acquiring each parameter is as follows:
number of shared band subchannels:
；
the working center frequency point of the sending terminal:
；
subchannel numbering:
；
center frequency point of mth subchannel:
。
further, according to the basic idea of dynamic spectrum access, a signal spectrum needs to be dynamically adjusted according to a shared (common) frequency band interval channel and an interference condition, see fig. 4, which is a schematic diagram of a broadband autonomous frequency-selective communication system based on an OFDM system in the existing scheme, as shown in fig. 4, that is, a broadband communication system supporting dynamic spectrum access requires that a signal spectrum needs to be dynamically reconfigurable, which means that a synchronization sequence spectrum of a communication waveform also supports dynamic reconfiguration, which adds a great challenge to synchronization sequence design. Therefore, how to make the synchronization sequence also support dynamic reconstruction is a problem to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide a synchronization method, a synchronization device, synchronization equipment and a storage medium of a wireless broadband communication system, so that a synchronization sequence supports dynamic reconstruction, and timing synchronization and frequency offset estimation of the wireless broadband communication system are realized.
In order to achieve the above object, the present invention provides a synchronization method for a wireless broadband communication system, including:
receiving a time domain received signal; the time domain receiving signal is a time domain sampling signal which is transmitted to a receiving end after a transmitting end dynamically selects a target sub-channel, a real pseudo-random sequence is transmitted on even number sub-carriers of the target sub-channel, and zeros are transmitted on odd number sub-carriers;
and determining a timing offset estimation result by utilizing the time domain receiving signal and the symbol timing offset estimation function, and executing synchronous operation according to the timing offset estimation result.
Wherein the symbol timing offset estimation function
Comprises the following steps:
；
in order to be a function of the correlation,
in order to normalize the terms for the energy,
represents the sample time index;
wherein,
；
wherein,Nin order to be the length of the synchronization symbol,
is a time-dependent index;
is a first intermediate variable that is a function of,
is the second intermediate variable, and is,
is an imaginary unit;
is a time domain received signal.
The time domain receiving signal comprises two sections of repeated sequence structures, and each section of repeated sequence structure comprises two sections of conjugate centrosymmetric sequences.
Wherein, the determining a timing offset estimation result by using the time domain received signal and the symbol timing offset estimation function and executing a synchronization operation according to the timing offset estimation result comprises:
obtaining a timing offset estimation result according to the conjugate central symmetric sequence in the time domain receiving signal and the symbol timing offset estimation function, and realizing symbol timing synchronization according to a peak value in the timing offset estimation result;
and determining a frequency offset estimation result according to the two-section repeated sequence structure in the time domain receiving signal, and performing frequency offset compensation by using the frequency offset estimation result to realize carrier synchronization.
To achieve the above object, the present invention further provides a synchronization apparatus for a wireless broadband communication system, comprising:
the signal receiving module is used for receiving a time domain receiving signal; the time domain receiving signal is a time domain sampling signal which is transmitted to a receiving end after a transmitting end dynamically selects a target sub-channel, a real pseudo-random sequence is transmitted on even number sub-carriers of the target sub-channel, and zeros are transmitted on odd number sub-carriers;
and the synchronization module is used for determining a timing offset estimation result by utilizing the time domain receiving signal and the symbol timing offset estimation function and executing synchronization operation according to the timing offset estimation result.
Wherein the symbol timing offset estimation function
Comprises the following steps:
；
in order to be a function of the correlation,
in order to normalize the terms for the energy,
represents the sample time index;
wherein,
；
wherein,Nin order to be the length of the synchronization symbol,
is a time-dependent index;
is a first intermediate variable that is a function of,
is the second intermediate variable, and is,
is an imaginary unit;
is a time domain received signal.
The time domain receiving signal comprises two sections of repeated sequence structures, and each section of repeated sequence structure comprises two sections of conjugate centrosymmetric sequences.
Wherein the synchronization module comprises:
the timing synchronization unit is used for obtaining a timing offset estimation result according to the conjugate central symmetric sequence in the time domain receiving signal and the symbol timing offset estimation function and realizing symbol timing synchronization according to a peak value in the timing offset estimation result;
and the carrier synchronization unit is used for determining a frequency offset estimation result according to the two-section repeated sequence structure in the time domain receiving signal, and performing frequency offset compensation by using the frequency offset estimation result to realize carrier synchronization.
To achieve the above object, the present invention further provides an electronic device comprising:
a memory for storing a computer program;
a processor for implementing the steps of the synchronization method of the wireless broadband communication system as described above when executing the computer program.
To achieve the above object, the present invention further provides a computer-readable storage medium having stored thereon a computer program, which when executed by a processor, implements the steps of the synchronization method of the wireless broadband communication system as described above.
According to the scheme, the embodiment of the invention provides a synchronization method, a synchronization device, synchronization equipment and a storage medium of a wireless broadband communication system; in the scheme, when the wireless broadband communication system realizes the dynamic reconstruction of the frequency spectrum, firstly, a subchannel for transmitting data needs to be selected, a real pseudo-random sequence is sent on an even subcarrier of the subchannel, and zeros are sent on an odd subcarrier of the subchannel, so that a synchronization sequence received by a receiving end has conjugate central symmetry and excellent synchronization performance; namely: when the wireless broadband communication system in the scheme realizes dynamic reconstruction of a frequency spectrum, even if only a part of molecular channels are selected and sequences are transmitted on sub-carriers contained in the partial channels according to the rule, time domain sequences corresponding to frequency domain sequences still meet the conjugate central symmetry property, and further synchronous operation can be executed. Therefore, the method and the device can construct a synchronous sequence with the spectrum dynamic reconfiguration capability by arranging the sub-channel information, and meet the requirements of cognitive radio dynamic requisition and spectrum resource release; and, by using the conjugate centrosymmetric property of the sequence to execute the synchronous operation, the synchronous operation has excellent synchronous performance; in addition, the timing function calculation method disclosed by the invention can greatly reduce the calculation complexity required for calculating the autocorrelation function by utilizing the conjugate centrosymmetric property and reduce the consumption of hardware resources.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of a OFDM waveform channel bandwidth subchannel division model in a conventional scheme;
FIG. 2 is a diagram of a design of an independent control channel according to a conventional scheme;
fig. 3 is a schematic diagram of a sub-channel division model of a radio frequency front end working frequency band in a conventional scheme;
fig. 4 is a schematic diagram of a broadband autonomous frequency-selective communication system based on an OFDM system according to the prior art;
FIG. 5 is a diagram of an OFDM system model of the prior art;
fig. 6 is a flow chart illustrating a synchronization method of a wireless broadband communication system according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a time domain structure of a Park training symbol disclosed in the embodiment of the present invention;
FIG. 8 is a graph illustrating a timing-offset estimation function according to an embodiment of the present invention;
FIG. 9 is a timing diagram illustrating another offset estimation function according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of a synchronization principle based on a conjugate centrosymmetric sequence according to an embodiment of the present invention;
fig. 11 is a schematic diagram illustrating an implementation of a synchronization method for an OFDM system with dynamically reconfigurable spectrum according to an embodiment of the present invention;
fig. 12 is a schematic structural diagram of a synchronization apparatus of a wireless broadband communication system according to an embodiment of the present invention;
fig. 13 is a schematic structural diagram of an electronic device according to an embodiment of the disclosure.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 5, which is a schematic diagram of an OFDM system model of the prior art, as shown in fig. 5, transmitted data is processed by channel coding, QAM (Quadrature Amplitude Modulation) mapping, IFFT (Inverse fast fourier Transform, fast algorithm for Inverse discrete fourier Transform), CP (Cyclic Prefix), and the like to obtain an OFDM signal, and then transmitted through a wireless channel. The receiving end firstly carries out synchronization processing on the received signal, estimates and compensates symbol timing and carrier frequency deviation, and then can ensure that the subsequent processes such as QAM demapping, channel decoding and the like are correctly carried out.
There have been many studies in this respect to the synchronization problem of the OFDM system so far. In an actual system, a synchronization method based on a training sequence is generally adopted, and although the training sequence can reduce the transmission efficiency of the system, it is worth to improve the speed, the precision and the stability of synchronization at the expense of a certain transmission efficiency. The OFDM system synchronization method based on the training sequence is known as Schmidl algorithm, Minn algorithm and Park algorithm, the basic idea of the methods is that a transmitting end transmits the training sequence with a specific repeating structure, a receiving end calculates the corresponding autocorrelation function of a received signal according to the repeating structure of the training sequence, and on the basis, symbol timing synchronization and carrier frequency offset estimation are respectively realized by utilizing autocorrelation peak values and phase information thereof. The Schmidl algorithm and the Minn algorithm mainly utilize a repetitive structure, so the implementation is simple, the requirements of synchronous sequence spectrum reconstruction can be met, and the performance is general. The Park algorithm can obviously improve the performance by utilizing the conjugate centrosymmetry property, but the calculation is complex and needs to occupy a large amount of calculation resources.
Therefore, the embodiment of the invention discloses a synchronization method, a synchronization device, synchronization equipment and a storage medium of a wireless broadband communication system, so that a synchronization sequence supports dynamic reconstruction, timing synchronization and frequency offset estimation of the wireless broadband communication system are realized, and consumption of hardware resources is reduced.
Referring to fig. 6, a synchronization method of a wireless broadband communication system according to an embodiment of the present invention includes:
s101, receiving a time domain receiving signal; the time domain receiving signal is a time domain sampling signal which is transmitted to a receiving end after a transmitting end dynamically selects a target sub-channel, a real pseudo-random sequence is transmitted on even number sub-carriers of the target sub-channel, and zeros are transmitted on odd number sub-carriers;
it should be noted that, depending on the nature of the discrete Fourier transform, if
，
For real sequences, the Fourier transform is characterized by conjugate centrosymmetry, i.e.
. On the basis, Park provides a synchronous sequence construction method, which transmits real pseudo-random (PN) sequences only on even subcarriers in a frequency domain, wherein the sequence length is N/2, namely half of the OFDM symbol length; no sequence is transmitted on odd subcarriers (i.e., 0 is transmitted). The fourier transform result thereof exhibits the characteristics shown in fig. 7, which can be simplified as
Wherein
and
has a conjugate central symmetry, and
and a first
Each element is an equal real number, h in fig. 7. Defining a symbol timing offset estimation function as follows according to the conjugate central symmetry of the synchronization sequence:
wherein,
in order to be a function of the correlation,
in order to normalize the terms for the energy,Nin order to be the length of the synchronization symbol,
is a time-dependent index;
which is indicative of the received signal or signals,
indicating the sample time index. In an ideal noise-free background, the timing offset estimation function curve is shown in fig. 8, and the timing offset estimation is as follows:
it can be seen that when the synchronous operation is executed by the Park algorithm, the synchronous performance can be improved according to the symmetric property of the conjugate center; moreover, since a wideband communication system supporting dynamic spectrum access requires dynamic reconstruction of a signal spectrum, which means that a synchronization sequence spectrum of a communication waveform also supports dynamic reconstruction, if a subcarrier of transmission data is dynamically changed in units of subcarriers at this time, the conjugate centrosymmetry property of a synchronization sequence received by a receiving end is affected after the subcarrier of the transmission sequence is dynamically adjusted.
In the present application, the spectrum interval will be shared
Is divided into
A sub-channel numbered as
Each sub-channel is composed of
Sub-carrier composition, having in common
And (4) sub-carriers. And, each sub-channel utilizes considering adjacent channel interference between sub-channels in a practical system
The virtual sub-carriers are used for adjacent channel protection, so the essential requirement that the synchronous sequence frequency spectrum can be dynamically reconstructed is to arbitrarily select the virtual sub-carriers under the condition of considering the virtual sub-carriers
In the case that some of the sub-channels transmit information, and the remaining sub-channels do not transmit information (i.e., the corresponding sub-carriers transmit 0), the time domain sequences corresponding to the frequency domain sequences thereof satisfy the properties required by a typical synchronization method, such as conjugate symmetry properties or a repeating structure. The present invention is illustrated by taking the property of conjugate centrosymmetry as an example.
Therefore, in the present application, in order to dynamically reconstruct the synchronization sequence spectrum, similar to the Park synchronization sequence construction method, the spectrum interval is shared
PartitioningIs composed of
The sub-channels comprising
The method comprises the following steps that subcarriers are taken as objects, real pseudo-random (PN) sequences are sent on even subcarriers in a frequency domain, and the sequence length is ML/2, namely half of the OFDM symbol length of a sending end; no sequence is transmitted on odd subcarriers (i.e., 0 is transmitted). The fourier transform results thereof will also exhibit the characteristics shown in fig. 7. On the basis, according to the communication requirement of dynamic spectrum reconstruction, a plurality of required sub-channels are selected to transmit sequences on the sub-carriers contained in the sub-channels according to the rule, and the sequences are not transmitted on the sub-carriers contained in the other unselected sub-channels (namely, 0 is transmitted). Since the original sequence only transmits real pseudo-random (PN) sequences on even subcarriers and does not transmit sequences on odd subcarriers (namely 0), even if only the sequences of the partial channels in the original sequence are transmitted on the subcarriers contained by the partial channels according to the rule, the whole sequence is transmitted on the subcarriers
The sequence of subcarriers still satisfies the characteristics of the even subcarrier transmission sequence and the odd subcarrier transmission sequence is 0, so the fourier transform result thereof also exhibits the characteristics shown in fig. 7. Therefore, the synchronization sequence constructed by the method, the Park algorithm and the proposed new time-frequency synchronization method are still applicable.
S102, determining a timing offset estimation result by utilizing a time domain receiving signal and a symbol timing offset estimation function, and executing synchronization operation according to the timing offset estimation result.
Further, referring to equation (2), the timing offset estimation function
Between two adjacent points there is
Different product pairs, which increase the difference between the value of the correct starting point of the symbol and other points, and improve the estimation precision; however, to ensure the estimation accuracy
The value is often large, so that
When the size of the communication device is large, the number of needed multipliers is large, a large amount of hardware resources are consumed, and great challenges are brought to power consumption, size and cost of hardware implementation of the communication device. Thus in the present application, a symbol timing offset estimation function is disclosed
The method specifically comprises the following steps:
wherein,
（6）
wherein,
in order to be a function of the correlation,
to be able toThe term of the quantity normalization is used,
represents the sample time index;Nin order to be the length of the synchronization symbol,
is a time-dependent index;
is a first intermediate variable that is a function of,
is the second intermediate variable, and is,
is an imaginary unit;
is a time domain received signal.
It should be noted that, in an ideal noise-free background, the timing offset estimation function curve described in the above equation (5) is shown in fig. 9. And, the timing offset estimation function of equation (5)
Between two adjacent points there is
The different summation pairs also fully utilize the conjugate central symmetry property of the sequence to increase the difference between the numerical value of the correct starting point of the symbol and other points, thereby improving the estimation precision.
The time domain received signal in the present application includes two segments of repeating sequence structures, and each segment of repeating sequence structure includes two segments of conjugate centrosymmetric sequences, so that the present application determines a timing offset estimation result by using the time domain received signal and a symbol timing offset estimation function, and when performing a synchronization operation according to the timing offset estimation result, the method specifically includes: obtaining a timing offset estimation result according to a conjugate central symmetric sequence and a symbol timing offset estimation function in a time domain receiving signal, and realizing symbol timing synchronization according to a peak value in the timing offset estimation result; and determining a frequency offset estimation result according to the two-section repeated sequence structure in the time domain receiving signal, and performing frequency offset compensation by using the frequency offset estimation result to realize carrier synchronization.
Specifically, because the conjugate centrosymmetric synchronization sequence shown in fig. 7 can only perform timing offset estimation, and because there is only one correlation peak, it is difficult to reasonably determine the decision rule, and it is difficult to achieve high-precision peak detection under the condition of low signal-to-noise ratio. To solve this problem, a synchronization sequence structure shown in fig. 10 is proposed, which is composed of four conjugated centrosymmetric sequences and has a two-segment repeat sequence structure. Therefore, the method and the device can realize the frequency offset estimation by utilizing the repeated structure while realizing the accurate estimation of the timing offset by utilizing the conjugate centrosymmetry property. Further, FIG. 10 shows the basic procedure of timing offset estimation by calculating separately
And
is a periodic conjugate correlation function, wherein
The periodic conjugate correlation function occurs at intervals of
The number of 3 peaks of the signal line,
1 peak appears for the periodic conjugate correlation function, and the peak appears at the position and
periodic conjugate correlation functionThe middle peak positions of the numbers coincide. The correlation between these peaks provides an additional criterion for implementing timing offset estimation, which can improve the accuracy of timing offset estimation under low signal-to-noise ratio conditions.
Meanwhile, according to the 2-segment repeat structure in the synchronization sequence shown in FIG. 9, the method can obtain
The corresponding frequency offset estimate is:
wherein,
is estimated in the range of
Normalizing the subcarrier frequency offset.
Referring to fig. 11, a schematic diagram of an implementation of a synchronization method for an OFDM system with dynamically reconfigurable spectrum according to an embodiment of the present invention is disclosed, a synchronization sequence structure of the synchronization method is shown in fig. 10, and an implementation module structure of the synchronization method is shown in fig. 11. The device comprises an accumulation calculating unit with the received signal length of N/2, an accumulation calculating unit with the received signal length of N, a new timing function calculating unit, a peak value search realization timing synchronization unit, a frequency offset estimating unit and a frequency offset compensating unit. In summary, the method can construct a synchronization sequence with spectrum dynamic reconfiguration capability by arranging the subchannel information, and meet the requirements of cognitive radio dynamic demand and spectrum resource release; and, by performing the synchronization operation using the conjugate centrosymmetric property of the sequence, the synchronization operation has excellent synchronization performance. Secondly, the application also provides a novel timing function calculation method based on addition operation, which can greatly reduce the calculation complexity required by calculating the autocorrelation function by utilizing the conjugate centrosymmetry property and reduce the consumption of hardware resources.
The following describes a synchronization apparatus provided in an embodiment of the present invention, and the synchronization apparatus described below and the synchronization method described above may be referred to each other.
Referring to fig. 12, a schematic structural diagram of a synchronization apparatus of a wireless broadband communication system according to an embodiment of the present invention includes:
a signal receiving module 100, configured to receive a time-domain received signal; the time domain receiving signal is a time domain sampling signal which is transmitted to a receiving end after a transmitting end dynamically selects a target sub-channel, a real pseudo-random sequence is transmitted on even number sub-carriers of the target sub-channel, and zeros are transmitted on odd number sub-carriers;
a synchronization module 200, configured to determine a timing offset estimation result by using the time domain received signal and the symbol timing offset estimation function, and perform a synchronization operation according to the timing offset estimation result.
Wherein the symbol timing offset estimation function
Comprises the following steps:
；
in order to be a function of the correlation,
in order to normalize the terms for the energy,
represents the sample time index;
wherein,
；
wherein,Nin order to be the length of the synchronization symbol,
is a time-dependent index;
is a first intermediate variable that is a function of,
is the second intermediate variable, and is,
is an imaginary unit;
is a time domain received signal.
The time domain receiving signal comprises two sections of repeated sequence structures, and each section of repeated sequence structure comprises two sections of conjugate centrosymmetric sequences.
Wherein the synchronization module comprises:
the timing synchronization unit is used for obtaining a timing offset estimation result according to the conjugate central symmetric sequence in the time domain receiving signal and the symbol timing offset estimation function and realizing symbol timing synchronization according to a peak value in the timing offset estimation result;
and the carrier synchronization unit is used for determining a frequency offset estimation result according to the two-section repeated sequence structure in the time domain receiving signal, and performing frequency offset compensation by using the frequency offset estimation result to realize carrier synchronization.
Referring to fig. 13, an embodiment of the present invention further discloses a structural schematic diagram of an electronic device, including:
a memory 11 for storing a computer program;
a processor 12 for implementing the steps of the synchronization method of the wireless broadband communication system according to any of the above-mentioned method embodiments when executing the computer program.
In this embodiment, the device may be a PC (Personal Computer), or may be a terminal device such as a smart phone, a tablet Computer, a palmtop Computer, or a portable Computer.
The device may include a memory 11, a processor 12, and a bus 13.
The memory 11 includes at least one type of readable storage medium, which includes a flash memory, a hard disk, a multimedia card, a card type memory (e.g., SD or DX memory, etc.), a magnetic memory, a magnetic disk, an optical disk, and the like. The memory 11 may in some embodiments be an internal storage unit of the device, for example a hard disk of the device. The memory 11 may also be an external storage device of the device in other embodiments, such as a plug-in hard disk provided on the device, a Smart Memory Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like. Further, the memory 11 may also include both an internal storage unit of the device and an external storage device. The memory 11 may be used not only to store application software installed in the device and various kinds of data such as program codes for performing a synchronization method, etc., but also to temporarily store data that has been output or is to be output.
The processor 12 may be a Central Processing Unit (CPU), controller, microcontroller, microprocessor or other data Processing chip in some embodiments, and is used for executing program codes stored in the memory 11 or Processing data, such as program codes for executing a synchronization method.
The bus 13 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 13, but this is not intended to represent only one bus or type of bus.
Further, the device may further include a network interface 14, and the network interface 14 may optionally include a wired interface and/or a wireless interface (e.g., WI-FI interface, bluetooth interface, etc.), which are generally used to establish a communication connection between the device and other electronic devices.
Optionally, the device may further comprise a user interface 15, the user interface 15 may comprise a Display (Display), an input unit such as a Keyboard (Keyboard), and the optional user interface 15 may further comprise a standard wired interface, a wireless interface. Alternatively, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, or the like. The display, which may also be referred to as a display screen or display unit, is suitable for displaying information processed in the device and for displaying a visualized user interface.
Fig. 13 shows only the device with the components 11-15, and it will be understood by those skilled in the art that the structure shown in fig. 13 does not constitute a limitation of the device, and may comprise fewer or more components than those shown, or some components may be combined, or a different arrangement of components.
The embodiment of the invention also discloses a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and when the computer program is executed by a processor, the steps of the synchronization method of the wireless broadband communication system in any method embodiment are realized.
Wherein the storage medium may include: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. A synchronization method for a wireless broadband communication system, comprising:
receiving a time domain received signal; the time domain receiving signal is a time domain sampling signal which is transmitted to a receiving end after a transmitting end dynamically selects a target sub-channel, a real pseudo-random sequence is transmitted on even number sub-carriers of the target sub-channel, and zeros are transmitted on odd number sub-carriers;
determining a timing offset estimation result by utilizing the time domain receiving signal and a symbol timing offset estimation function, and executing synchronous operation according to the timing offset estimation result;
wherein the symbol timing offset estimation function
Comprises the following steps:
；
in order to be a function of the correlation,
in order to normalize the terms for the energy,
represents the sample time index;
wherein,
；
wherein N is the length of the synchronization symbol,
is a time-dependent index;
is a first intermediate variable that is a function of,
is the second intermediate variable, and is,
is an imaginary unit;
is a time domain received signal.
2. The synchronization method according to claim 1, wherein the time domain received signal comprises two repeated sequence structures, and each repeated sequence structure comprises two conjugated centrosymmetric sequences.
3. The synchronization method according to claim 2, wherein the determining a timing offset estimation result by using the time domain received signal and a symbol timing offset estimation function, and performing a synchronization operation according to the timing offset estimation result comprises:
obtaining a timing offset estimation result according to the conjugate central symmetric sequence in the time domain receiving signal and the symbol timing offset estimation function, and realizing symbol timing synchronization according to a peak value in the timing offset estimation result;
and determining a frequency offset estimation result according to the two-section repeated sequence structure in the time domain receiving signal, and performing frequency offset compensation by using the frequency offset estimation result to realize carrier synchronization.
4. A synchronization apparatus of a wireless broadband communication system, comprising:
the signal receiving module is used for receiving a time domain receiving signal; the time domain receiving signal is a time domain sampling signal which is transmitted to a receiving end after a transmitting end dynamically selects a target sub-channel, a real pseudo-random sequence is transmitted on even number sub-carriers of the target sub-channel, and zeros are transmitted on odd number sub-carriers of the real pseudo-random sequence;
a synchronization module, configured to determine a timing offset estimation result by using the time domain received signal and a symbol timing offset estimation function, and perform a synchronization operation according to the timing offset estimation result;
the symbol timing offset estimation function
Comprises the following steps:
；
in order to be a function of the correlation,
in order to normalize the terms for the energy,
represents the sample time index;
wherein,
；
wherein N is the length of the synchronization symbol,
is a time-dependent index;
is a first intermediate variable that is a function of,
is the second intermediate variable, and is,
is an imaginary unit;
is a time domain received signal.
5. The synchronization apparatus of claim 4, wherein the time-domain received signal comprises two repeated sequence structures, and each repeated sequence structure comprises two conjugated centrosymmetric sequences.
6. The synchronization apparatus of claim 5, wherein the synchronization module comprises:
the timing synchronization unit is used for obtaining a timing offset estimation result according to the conjugate central symmetric sequence in the time domain receiving signal and the symbol timing offset estimation function and realizing symbol timing synchronization according to a peak value in the timing offset estimation result;
and the carrier synchronization unit is used for determining a frequency offset estimation result according to the two-section repeated sequence structure in the time domain receiving signal, and performing frequency offset compensation by using the frequency offset estimation result to realize carrier synchronization.
7. An electronic device, comprising:
a memory for storing a computer program;
a processor for implementing the steps of the synchronization method of the wireless broadband communication system according to any one of claims 1 to 3 when executing the computer program.
8. A computer-readable storage medium, characterized in that a computer program is stored thereon, which computer program, when being executed by a processor, carries out the steps of the synchronization method of a wireless broadband communication system according to any one of claims 1 to 3.
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