WO2022120676A1 - 低轨卫星通信中的随机接入信道传输方法及装置 - Google Patents

低轨卫星通信中的随机接入信道传输方法及装置 Download PDF

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WO2022120676A1
WO2022120676A1 PCT/CN2020/135121 CN2020135121W WO2022120676A1 WO 2022120676 A1 WO2022120676 A1 WO 2022120676A1 CN 2020135121 W CN2020135121 W CN 2020135121W WO 2022120676 A1 WO2022120676 A1 WO 2022120676A1
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sequence
dft
time
subcarriers
frequency
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PCT/CN2020/135121
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English (en)
French (fr)
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方冬梅
金星
林之楠
鲁志兵
杨芸霞
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海能达通信股份有限公司
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Priority to PCT/CN2020/135121 priority Critical patent/WO2022120676A1/zh
Publication of WO2022120676A1 publication Critical patent/WO2022120676A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/16—Discovering, processing access restriction or access information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA

Definitions

  • the invention relates to the field of low-orbit satellite communications, in particular to a random access channel transmission method and device in low-orbit satellite communications.
  • Satellite communication has become an indispensable and important means of global communication by virtue of its wide coverage, large communication capacity and good transmission quality.
  • the random access channel PRACH in satellite communication is mainly used for estimating uplink transmission timing error, estimating uplink frequency offset error and estimating SNR when users access.
  • the channel characteristics of satellite channels are that the coverage of satellite beams is very large, with an area of 60km*1000km. Before there is no uplink timing, the uplink timing error will be very large; and the speed of satellite communication and the carrier frequency used will lead to uplink.
  • the frequency offset error is also very large, and the residual uplink frequency offset is about ⁇ 30kHz; and the signal-to-noise ratio of satellite communication is low, the minimum can reach -10dB.
  • the transmit power of PRACH is lower than that of other channels, usually more than ten dB lower than that of PUSCH.
  • PRACH Due to the problem of frequent handover in satellite communication, PRACH needs to be transmitted frequently, so the rationality of PRACH design is very important.
  • the channel structure of the existing PRACH includes three parts, including three parts, CP, Preamble and GT.
  • the CP is used to cancel the interference caused by the different arrivals of the users
  • the Preamble is a random access sequence
  • the GT is used to prevent the Preamble from interfering with the signal for subsequent transmission.
  • the existing Preamble sequence adopts ZC (Zadoff-Chu) sequence to carry the signal to be transmitted. After research on the existing transmission process, it is found that the ZC sequence will appear spurious peaks when there is a frequency offset. When the frequency offset exceeds half of the subcarrier spacing, the energy of the spurious peaks is even larger than that of the main peak, resulting in the inability to determine the transmission. The main peak of the signal cannot effectively receive the signal.
  • the frequency offset of satellite communication is as high as ⁇ 30kHz. Under this frequency offset, even if the preamble configuration with a subcarrier spacing of 60kHz is used, there are cases where the main peak cannot be correctly judged. At the same time, when the subcarrier interval is larger, more frequency domain RBs are occupied, resulting in an increase in the overhead for PRACH. For example, the subcarrier spacing of 30 kHz occupies 18 RBs; the subcarrier spacing of 60 kHz occupies 35 RBs.
  • the technical problem to be solved by the present invention is to provide a random access channel transmission method in low-orbit satellite communication, which adopts a PN sequence in a set form to carry the signal to be transmitted, and avoids the occurrence of false peaks in the transmission process. , the main peak of the transmission signal can be directly determined, so that the terminal can access the base station in time, and then effectively receive the signal.
  • the present invention also provides a random access channel transmission device in low-orbit satellite communication, to ensure the implementation and application of the above method in practice.
  • a random access channel transmission method in low-orbit satellite communication is applied to a terminal, and the method includes:
  • the sequence form of the PN sequence is a frequency domain PN sequence
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the frequency domain PN sequence is directly mapped onto the subcarriers.
  • the sequence form of the PN sequence is a discrete Fourier transform-extended orthogonal frequency division multiplexing DFT-s-OFDM modulated PN sequence
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain is mapped onto the subcarriers.
  • the sequence form of the PN sequence is a frequency domain PN sequence associated with a walsh orthogonal code
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the frequency domain PN sequence associated with the walsh orthogonal code is directly mapped onto the subcarriers.
  • the sequence form of the PN sequence is a PN sequence modulated by an orthogonal frequency division multiplexing DFT-s-OFDM modulated by a discrete Fourier transform associated with a walsh orthogonal code;
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain and associated with the walsh orthogonal code is mapped onto the subcarriers.
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain is mapped to the subcarriers Before going on, it also includes:
  • Windowing is performed on the DFT-s-OFDM modulated PN sequence transformed to the frequency domain.
  • the DFT associated with the walsh orthogonal code transformed to the frequency domain -The PN sequence modulated by s-OFDM, before being mapped to the subcarriers, further includes:
  • Windowing is performed on the DFT-s-OFDM modulated PN sequence transformed to the frequency domain and associated with the walsh orthogonal code.
  • the transmitting to the base station in a predetermined form includes:
  • the PN sequence converted to the time domain is transmitted to the base station in the form of ZP before it and GT after it, the ZP is an empty field, and the length of the ZP is 1 ⁇ 1 of the CP length of the OFDM symbol in the data area. 2 times.
  • a random access channel transmission device in low-orbit satellite communication the device is applied to a terminal, and the device includes:
  • the selection unit is used to select a PN sequence of a set form in the set PN sequence set;
  • mapping unit configured to map the PN sequence to the subcarriers in a preset transformation mode
  • a transmitting unit configured to perform an inverse fast Fourier transform IFFT on the subcarriers mapped with the PN sequence, so as to transform the subcarriers mapped with the PN sequence into the time domain, and in a predetermined form transmitted to the base station.
  • a random access channel transmission method in low-orbit satellite communication is applied to a base station, and the method includes:
  • each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data to detect peaks in the time-frequency resource data;
  • the PN sequence in the form of the set sequence that is currently correlated with the time-frequency resource data is determined as the PN sequence sent by the terminal.
  • the PN sequences in the set sequence form in the set PN sequence set are respectively correlated with the time-frequency resource data, including:
  • Each PN sequence subsection of the PN sequence in each set sequence form is respectively correlated with the time domain resource data, and the correlation includes time domain sliding correlation and frequency domain correlation.
  • a random access channel transmission device in low-orbit satellite communication the device is applied to a base station, comprising:
  • a detection unit configured to correlate each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data to detect peaks in the time-frequency resource data
  • a determining unit configured to determine the PN sequence in the form of a set sequence that is currently correlated with the time-frequency resource data as the PN sequence sent by the terminal when a peak in the time-frequency resource data is detected.
  • the present invention includes the following advantages:
  • the present invention provides a random access channel transmission method in low-orbit satellite communication, comprising: selecting a PN sequence in the form of a set sequence from a set of set PN sequences; The transformation method of the PN sequence is mapped to the sub-carrier; the inverse fast Fourier transform IFFT is performed on the sub-carrier mapped with the PN sequence, so as to transform the sub-carrier mapped with the PN sequence to the time domain, and transmitted to the base station in a predetermined form.
  • the random access channel transmission method provided by the present invention adopts the PN sequence in the form of a set sequence to carry the signal to be transmitted, replaces the ZC sequence used by the existing Preamble sequence, and avoids the occurrence of false peaks in the transmission process.
  • the main peak can be more effectively identified, so that the terminal can access the base station in time, so that the base station can effectively receive the signal.
  • the CP does not need to be transmitted, thereby saving time overhead.
  • 1 is a method flowchart of a random access channel transmission method in a low-orbit satellite communication provided by the present invention
  • FIG. 2 is a schematic structural diagram of a random access channel transmission device in a low-orbit satellite communication provided by the present invention
  • FIG. 3 is a flowchart of another method of a random access channel transmission method in a low-orbit satellite communication provided by the present invention.
  • FIG. 4 is another schematic structural diagram of a random access channel transmission method in a low-orbit satellite communication provided by the present invention.
  • FIG. 5 is a schematic structural diagram of a random access channel transmission system in a low-orbit satellite communication provided by the present invention
  • FIG. 6 is a communication principle diagram of a random access channel transmission system in a low-orbit satellite communication provided by the present invention.
  • FIG. 7 is a schematic structural diagram of an electronic device provided by the present invention.
  • the present invention may be used in numerous general purpose or special purpose computing device environments or configurations.
  • the embodiment of the present invention provides a random access channel transmission method in low-orbit satellite communication.
  • the execution body of the method may be a processor in a terminal.
  • the random access in low-orbit satellite communication provided by the embodiment of the present invention is The method flowchart of the channel transmission method is shown in Figure 1, including:
  • a PN sequence set is set, the PN sequence set is set with a plurality of PN sequences with a set sequence form, and the set form of each PN sequence in the PN sequence set is set same.
  • the PN sequences in the PN sequence set can be set in a variety of different sequence forms.
  • both the base station and each terminal can read each PN sequence in the set sequence form in the PN sequence set.
  • the terminal When the terminal needs to perform random access channel transmission, it can select a PN sequence in the set sequence form from the PN sequence set. The actual selection process can be based on the data type to be transmitted. After the sequence form of the PN sequence is set, it is randomly selected.
  • the PN sequence selected from the PN sequence set is used to replace the original ZC sequence in the Preamble sequence, and the random access channel During the transmission process, the selected PN sequence is mapped to the subcarriers according to the preset transformation mode.
  • S103 Perform inverse fast Fourier transform IFFT on the subcarriers mapped with the PN sequence, so as to transform the subcarriers mapped with the PN sequence into the time domain, and transmit to the base station in a predetermined form .
  • the process of random access channel transmission it is necessary to perform inverse fast Fourier transform on the sub-carriers mapped with the PN sequence, and transform the sub-carriers mapped with the PN sequence into the time domain to obtain the Time-frequency resource data corresponding to the subcarriers mapped with the PN sequence in the time domain, and the time-frequency resource data is transmitted to the base station in a predetermined form.
  • a set sequence form is selected from the set of set PN sequences
  • the selected PN sequence is used as the signal-bearing sequence of the Preamble sequence in the random access channel, and the selected PN sequence is mapped to the subcarriers in a certain transformation method, and then the inverse fast Fourier transform is performed on the subcarriers mapped with the PN sequence, and the The subcarrier is transformed into the time domain, and the time-frequency resource data transformed into the time domain is transmitted to the base station in a predetermined form, so as to realize the process of applying the random access channel for transmission.
  • the sequence is used as the bearer sequence of the signal, which avoids the occurrence of false peaks during the access process, and can accurately identify the main peak of the data, so that the terminal can access the base station in time and realize the effective transmission of the signal.
  • the method provided by the embodiment of the present invention is implemented on the basis of researching the existing random access channel transmission process.
  • the ZC sequence adopted by the Preamble sequence may appear pseudo peaks when there is a frequency offset, When the frequency offset exceeds half of the subcarrier spacing, the energy of the spurious peak is even larger than that of the main peak. Even if the frequency offset is equal to half of the subcarrier spacing, if there is timing offset, additive white Gaussian noise, phase noise, etc., the energy of the spurious peak will be lower than that of the main peak.
  • the frequency offset of satellite communication is as high as ⁇ 30kHz.
  • the subcarrier spacing of 30 kHz occupies 18 RBs; the subcarrier spacing of 60 kHz occupies 35 RBs.
  • the PN sequence is used to replace the ZC sequence in the Preamble sequence.
  • the preset PN sequence set is provided with a preset number of PN sequences
  • the sequence form of each PN sequence in the PN sequence set is the same, for example, the sequence form of each PN sequence in the PN sequence set is the frequency domain PN sequence.
  • the sequence content of each PN sequence in the PN sequence set is different.
  • the PN sequence set provided in the embodiment of the present invention may be set in the terminal or in the base station, preferably in a local third-party system, and both the terminal and the base station can access the PN sequence set.
  • multiple sequence forms can be set for each PN sequence in the PN sequence set.
  • four PN sequence sets with different sequence forms are set , which can be respectively:
  • the sequence form of the PN sequence is the frequency domain PN sequence
  • the sequence form of the PN sequence is the PN sequence modulated by the discrete Fourier transform extended orthogonal frequency division multiplexing DFT-s-OFDM;
  • the sequence form of the PN sequence is a frequency domain PN sequence associated with a walsh orthogonal code
  • the sequence form of the PN sequence is the PN sequence modulated by the DFT-s-OFDM modulated orthogonal frequency division multiplexing associated with the discrete Fourier transform of the walsh orthogonal code.
  • the PN sequences in the above four sequence forms correspond to four PN sequence sets respectively, and can be set according to the types of data signals that actually need to be transmitted during the specific random access channel transmission process.
  • the frequency domain PN sequence when the frequency domain PN sequence is used, since the transmit power of PRACH is low, it can be considered that the time domain peak-to-average ratio problem caused by the frequency domain PN sequence can be considered to a certain extent. accept. Therefore, in the actual transmission process, it is necessary to map the PN sequence of the set form to the subcarriers in a certain manner in the form of the frequency domain.
  • the peak-to-average ratio is relatively low. The effect of channel transmission can be ignored.
  • the described PN sequence is mapped to a subcarrier in a preset transformation mode, including:
  • the frequency domain PN sequence is directly mapped onto the subcarriers.
  • the same PRACH time-frequency resource supports multiple users to perform random access with different PN sequences.
  • the frequency domain PN sequence can be directly mapped to its corresponding subcarrier. This process is applicable to the PN sequences in the four different sequence forms provided by the embodiment of the present invention, and after being transformed into the frequency domain, random access can be performed on the PN sequences of multiple users.
  • each PN sequence is 512 points.
  • the terminal can select a PN sequence from 64 kinds of PN sequences, map it to the corresponding sub-carriers at the interval of 30 kHz, occupy 12 RB positions in total, and then perform IFFT transformation to the time domain for transmission.
  • windowing processing may be performed on the frequency-domain PN sequence, and the windowing processing may be a Hamming window or a root Raised cosine window, etc.
  • the subcarrier may be understood as the subcarrier corresponding to the PN sequence selected in the transmission process.
  • the sequence form of the PN sequence is a discrete Fourier transform extended orthogonal frequency division multiplexing DFT-s-OFDM modulated PN sequence
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain is mapped onto the subcarriers.
  • each PN sequence in the PN sequence is a PN sequence modulated by DFT-s-OFDM
  • 64 kinds of PN sequences can be set in the PN sequence set, and the PN sequence of each PN sequence
  • the sequence form is a PN sequence modulated by DFT-s-OFDM
  • each PN sequence uses a different sequence initialization ID
  • each PN sequence is 512 points.
  • the terminal can select a PN sequence from 64 kinds of PN sequences, and then perform a 512-point fast Fourier transform FFT to transform the DFT-s-OFDM modulated PN sequence into the frequency domain, and then It is mapped to the corresponding subcarriers spaced at 30kHz, occupying a total of 12 RB positions.
  • the DFT-s-OFDM modulated PN sequence Before the s-OFDM modulated PN sequence is mapped onto the subcarriers, window processing is performed on the DFT-s-OFDM modulated PN sequence transformed to the frequency domain.
  • the windowing process may be a Hamming window or a root raised cosine window, etc., and then perform IFFT transformation to the time domain for transmission.
  • the sequence form of the PN sequence is a frequency domain PN sequence associated with a walsh orthogonal code
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the frequency domain PN sequence associated with the walsh orthogonal code is directly mapped onto the subcarriers.
  • the association between the frequency domain PN sequence and the walsh orthogonal code may be in the form of frequency domain PN sequence+walsh orthogonal code.
  • frequency domain PN sequence + walsh orthogonal code four kinds of frequency domain PN sequences can be set, each frequency domain PN sequence uses a different sequence initialization ID, and each PN sequence is 512 points. And set 16 walsh codes with a length of 16. There are 64 combinations of frequency domain PN sequences and walsh codes. There are 64 frequency domain PN sequences associated with walsh orthogonal codes in the PN sequence set.
  • the terminal can select one of 64 combinations of frequency-domain PN sequences + walsh codes, map it to the corresponding sub-carriers at 30kHz intervals, occupy 12 RB positions in total, and then perform IFFT transformation to time-domain transmission. go out.
  • the sequence form of the frequency domain PN sequence+walsh code can be directly mapped to the subcarriers corresponding to the PN sequence.
  • the combination of the frequency-domain PN sequence+walsh code may be subjected to windowing processing, and the The window processing can be a Hamming window, a root raised cosine window, or the like.
  • the sequence form of the PN sequence is a PN sequence modulated by an orthogonal frequency division multiplexing DFT-s-OFDM modulated by a discrete Fourier transform extension associated with a walsh orthogonal code;
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain and associated with the walsh orthogonal code is mapped onto the subcarriers.
  • the association between the PN sequence modulated by DFT-s-OFDM and the walsh orthogonal code may be in the form of a PN sequence modulated by DFT-s-OFDM+walsh code.
  • DFT-s-OFDM modulated PN sequence + walsh code four DFT-s-OFDM modulated PN sequences can be set, and each DFT-s-OFDM modulated PN sequence uses a different sequence initialization ID.
  • the PN sequence of each DFT-s-OFDM modulation is 512 points, and 16 walsh codes of length 16 are set. There are a total of 64 combinations of PN sequences and walsh codes modulated by DFT-s-OFDM.
  • the PN sequence set contains 64 PN sequences modulated by DFT-s-OFDM associated with walsh codes.
  • the terminal can select one of the 64 combinations of DFT-s-OFDM modulated PN sequence + walsh code, and then perform a 512-point FFT to associate the DFT-s-
  • the PN sequence modulated by the OFDM is transformed into the frequency domain and mapped to the subcarriers corresponding to the 30kHz interval, occupying a total of 12 RB positions.
  • the DFT associated with the walsh orthogonal code in order to reduce interference to the PUSCH of other subcarriers, can be -After the PN sequence modulated by s-OFDM is transformed into the frequency domain, the DFT-s-OFDM modulated PN sequence associated with the walsh orthogonal code transformed into the frequency domain is transformed into the subcarrier before being mapped to the subcarrier. Windowing is performed on the DFT-s-OFDM modulated PN sequence associated with the walsh orthogonal code in the frequency domain.
  • the windowing process may be a Hamming window, a root raised cosine window, or the like.
  • the IFFT is transformed to the time domain for transmission.
  • the ZC sequence needs the CP length, and the CP length here is relatively long.
  • the CP at 30 kHz is the Preamble symbol repeated 3 times, and the 60 kHz is the Preamble symbol repeated 12 times. Every time the Preamble symbol appears, there will be main peaks and false peaks. The final result is that there will be many peaks, which increases the difficulty of judging the first peak and the difficulty of multi-user peak resolution. Therefore, in the random access channel transmission method provided by the embodiment of the present invention, no matter which type of PN sequence is used for transmission, in the process of mapping the PN sequence to the subcarrier and transmitting it, no CP may be required.
  • ZP means nothing, and the length can be 1 to 2 times the CP length of the OFDM symbol in the data area.
  • the CP of the OFDM symbol in the data area in the satellite communication protocol is 0.59us
  • the CP of the OFDM symbol of Preamble is 200us
  • the length of ZP is 0.59us to 1.18us.
  • the function of ZP is to avoid the interference of the delay of the uplink symbols of other users to the Preamble symbols of this user. Because other users have already performed uplink synchronization when transmitting uplink symbols, the delay generally does not exceed the CP length of ordinary OFDM symbols, so the length of ZP is set to 1 to 2 times the CP length of OFDM symbols in the data area.
  • GT is reserved to avoid interference to subsequent signal symbols.
  • the transmitting to the base station in a predetermined form includes:
  • the PN sequence converted to the time domain is transmitted to the base station in the form of ZP before it and GT after it, the ZP is an empty field, and the length of the ZP is 1 ⁇ 1 of the CP length of the OFDM symbol in the data area. 2 times.
  • time-frequency resource data after the selected PN sequence is transformed into the time domain is obtained, and ZP is set before the time-frequency resource data, so After the time-frequency resource data, the GT is set and sent to the base station.
  • the PreambleCP with a large time overhead is not required, but only the ZP with a small time overhead is required, which saves the time overhead.
  • an embodiment of the present invention further provides a random access channel transmission device in a low-orbit communication satellite, which is used for the specific implementation of the method in FIG. 1 .
  • the access channel transmission apparatus can be applied to computer terminals or various mobile devices, and its schematic structural diagram is shown in FIG. 2 , and the apparatus includes:
  • Selection unit 201 is used to select a PN sequence of a set form in the set PN sequence set;
  • mapping unit 202 configured to map the PN sequence to a subcarrier in a preset transformation mode
  • the transmitting unit 203 is configured to perform an inverse fast Fourier transform (IFFT) on the subcarriers mapped with the PN sequence, so as to transform the subcarriers mapped with the PN sequence into the time domain, and convert the subcarriers mapped with the PN sequence to a predetermined form transmitted to the base station.
  • IFFT inverse fast Fourier transform
  • a set sequence is selected from the set of set PN sequences
  • the PN sequence of the form is used as the signal bearing sequence of the Preamble sequence in the random access channel, and the selected PN sequence is mapped to the subcarriers in a certain transformation mode, and then the inverse fast Fourier transform is performed on the subcarriers mapped with the PN sequence. Transform the subcarrier into the time domain, and transmit the time-frequency resource data transformed into the time domain to the base station in a predetermined form, so as to realize the process of applying the random access channel for transmission.
  • the PN sequence is used as the carrier sequence of the signal, which avoids the occurrence of false peaks during the transmission process, and can accurately identify the main peak of the data, so that the terminal can access the base station in time, so that the base station can effectively receive the signal, and realize the effective transmission of the signal.
  • an embodiment of the present invention also provides an implementation process of a random access channel transmission method in low-orbit satellite communication at the base station side, and the execution subject of the random access channel transmission method implemented at the base station side may be the base station.
  • the processor at the place, the processor can read each PN sequence in the set PN sequence set, and the method includes:
  • the base station when the terminal sends the time domain signal to the base station, the base station obtains the time-frequency resource data sent by the terminal, and the time-frequency resource data is the PN sequence selected by the terminal and mapped to the time domain corresponding to The time-frequency resource data of the time-frequency resource data, the GT is set after the time-frequency resource data.
  • S302 Correlate each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data, respectively, to detect peaks in the time-frequency resource data;
  • the processor on the base station side reads each PN sequence in the set sequence form in the set PN sequence set one by one from the set PN sequence set, and reads each PN sequence in the set sequence form one by one.
  • the PN sequences in the set sequence form are respectively correlated with the time-frequency resource data to detect peaks in the time-frequency resource data. It should be noted that the PN sequence set read by the base station side and the PN sequence set read by the terminal side are the same PN sequence set.
  • the PN sequence in the form of a set sequence currently correlated with the time-frequency resource data is the PN sequence adopted by the terminal , thereby allowing the terminal to access the base station.
  • the base station side after acquiring the time-frequency resource data sent by the terminal side, the base station side obtains the PN of each set form in the set of set PN sequences by acquiring sequence, and correlates the acquired PN sequences to detect the peaks in the time-frequency resource data, and then determines the PN sequence used by the terminal side, so as to allow the terminal to access the base station through the PN sequence, and realize the effective signal transmission of the base station. take over.
  • the correlation of each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data respectively includes:
  • Each PN sequence subsection of the PN sequence in the set sequence form is respectively correlated with the time domain resource data, and the correlation includes time domain sliding correlation and frequency domain correlation.
  • the base station When the preset format of the PN sequence selected by the terminal in the PN sequence set is a frequency domain PN sequence, the base station performs the following operations:
  • the receiving end of the base station intercepts the Preamble symbol + GT length (the ZP part of the data is not intercepted), obtains the data of the corresponding time-frequency resource, and traverses the local 64 PN sequences, each PN sequence is segmented with the received PRACH data. , if the number of segments is 4, that is, the data of 512 points is divided into 4 segments and the data of 128 points is respectively correlated with the transmitted data.
  • the correlation can be two kinds of time domain sliding correlation and frequency domain correlation.
  • the PN sequence sent by the terminal and the corresponding timing offset TO position can be obtained.
  • the frequency deviation FO can be obtained by calculating the phase difference of the 4-segment correlation values corresponding to the peak value.
  • the PRACH time domain signal received by the base station is, set the length to be (including the Preamble symbol + GT length), and the time domain sequence corresponding to a certain local PN frequency domain sequence is (IFFT transform of the PN frequency domain sequence).
  • the time-domain segmentation correlation method is:
  • the corresponding frequency domain piecewise correlation method is as follows:
  • the base station When the preset format of the PN sequence selected by the terminal in the PN sequence set is the PN sequence modulated by DFT-s-OFDM, the base station performs the following operations:
  • the receiving end of the base station intercepts the Preamble symbol + GT length (the ZP part of the data is not intercepted), obtains the data of the corresponding time-frequency resource, and traverses the local 64 kinds of PN sequences, each of which is related to the received PRACH data.
  • the number of segments is 4, that is, the 512-point data is divided into 4 segments and 128-point data are respectively correlated with the transmitted data.
  • the correlation can be two kinds of time domain sliding correlation and frequency domain correlation.
  • the PN sequence sent by the terminal and the corresponding timing offset TO position can be obtained.
  • the frequency deviation FO can be obtained by calculating the phase difference of the 4-segment correlation values corresponding to the peak value.
  • the time domain sliding correlation and frequency domain correlation methods are similar to the first example, and will not be repeated here. Those skilled in the art can understand the actual process of the second example on the basis of the first example. The difference is when The domain sequence is the local PN sequence.
  • the base station side When the set format of the PN sequence selected by the terminal in the PN sequence set is frequency domain PN sequence+walsh code, the base station side performs the following operations:
  • the receiving end of the base station intercepts the Preamble symbol + GT length (the ZP part of the data is not intercepted), obtains the data of the corresponding time-frequency resource, and traverses the combination of 64 local PN sequences + Walsh codes.
  • the received PRACH data is correlated in segments. For example, the number of segments is 4, that is, the data of 512 points is divided into 4 segments and the data of 128 points is correlated with the transmitted data respectively.
  • the correlation can be two kinds of time domain sliding correlation and frequency domain correlation.
  • the PN sequence sent by the terminal and the corresponding timing offset TO position can be obtained.
  • the frequency deviation FO can be obtained by calculating the phase difference of the 4-segment correlation values corresponding to the peak value.
  • time domain sliding correlation and frequency domain correlation methods are similar to the first example, and will not be repeated here.
  • Those skilled in the art can understand the actual process of the second example on the basis of the first example, which is similar to the first example. Instances differ in that the third instance has a different codeword from the first instance.
  • the base station When the preset format of the PN sequence selected by the terminal in the PN sequence set is DFT-s-OFDM modulated PN sequence + walsh code, the base station performs the following operations:
  • the receiving end of the base station intercepts the Preamble symbol + GT length (the ZP part of the data is not intercepted), obtains the data of the corresponding time-frequency resource, and traverses the combination of 64 local PN sequences + Walsh codes.
  • the received PRACH data is correlated in segments. For example, the number of segments is 4, that is, the data of 512 points is divided into 4 segments and the data of 128 points is correlated with the transmitted data respectively.
  • the correlation can be two kinds of time domain sliding correlation and frequency domain correlation.
  • the PN sequence sent by the terminal and the corresponding timing offset TO position can be obtained.
  • the frequency deviation FO can be obtained by calculating the phase difference of the 4-segment correlation values corresponding to the peak value.
  • the time domain sliding correlation and frequency domain correlation methods are similar to the second example, but the codewords are different.
  • a PN sequence or a PN sequence+Walsh orthogonal code is used as a random access codeword in low-orbit satellite communication.
  • the same PRACH time-frequency resource supports multiple users to perform random access with different PN sequences and Walsh orthogonal codes. No CP is required in front of PRACH, only a relatively short ZP is required.
  • the sequence for generating the uplink PRACH in the satellite communication protocol is changed from the ZC sequence to the PN sequence, or the PN sequence+Walsh sequence, so as to avoid the multi-peak problem of the ZC sequence under high frequency offset, and in many cases
  • the user greatly improves the detection success probability, TA estimation accuracy and frequency offset estimation accuracy, and can reduce the length of time occupied by the PRACH channel.
  • the timing and frequency offset can be estimated effectively and accurately, and there is only one peak value, which is convenient for retrieval.
  • CP is saved in the time domain, and the number of RBs in the frequency domain can also be reduced, which effectively saves PRACH overhead under large delay and large frequency offset.
  • an embodiment of the present invention further provides a random access channel transmission device in low-orbit satellite communication, which is used for the specific implementation of the method in FIG. 3 .
  • the random access channel transmission device in orbit satellite communication can be applied to the base station, and its schematic diagram is shown in FIG. 4 , and the device includes:
  • an obtaining unit 401 configured to obtain time-frequency resource data
  • a detection unit 402 configured to correlate each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data, respectively, to detect peaks in the time-frequency resource data;
  • the determining unit 403 is configured to, when a peak value in the video resource data is detected, determine the PN sequence in the form of a set sequence that is currently correlated with the time-frequency resource data as the PN sequence sent by the terminal.
  • the base station after acquiring the time-frequency resource data sent by the terminal, acquires each PN sequence in the set form in the set of pre-set PN sequences, and converts the acquired PN sequence to the Each PN sequence is correlated to detect peaks in the time-frequency resource data, and then determine the PN sequence adopted by the terminal side, so as to allow the terminal to access the base station through the PN sequence, and realize the effective reception of the signal by the base station.
  • a random access channel transmission system in low-orbit satellite communication is also provided, and the transmission system includes a terminal side and a base station side,
  • the terminal side includes:
  • the selection unit is used to select a PN sequence of a set form in the set PN sequence set;
  • mapping unit configured to map the PN sequence to the subcarriers in a preset transformation mode
  • a transmitting unit configured to perform an inverse fast Fourier transform IFFT on the subcarriers mapped with the PN sequence, so as to transform the subcarriers mapped with the PN sequence into the time domain, and in a predetermined form transmitted to the base station.
  • the base station side includes:
  • a detection unit configured to correlate each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data to detect peaks in the time-frequency resource data
  • a determining unit configured to determine the PN sequence in the form of a set sequence that is currently correlated with the time-frequency resource data as the PN sequence sent by the terminal when a peak in the time-frequency resource data is detected.
  • the random access channel transmission system in the low-orbit satellite communication replaces the ZC sequence in the existing Preamble sequence with the PN sequence, which effectively avoids the occurrence of false peaks in the transmission process, resulting in the inability to accurately determine the main peak. question.
  • the terminal can access the base station in time, and the effective transmission of the signal is realized.
  • FIG. 6 For the principle process of terminal and satellite communication in the random access channel transmission system in low-orbit satellite communication provided by the embodiment of the present invention, reference may be made to FIG. 6 provided by the embodiment of the present invention.
  • the link communicates with the onboard platform 502, which is connected to the gateway through a feeder link.
  • An embodiment of the present invention further provides a storage medium, where the storage medium includes a stored program, wherein when the program runs, a device on which the storage medium is located is controlled to perform random access channel transmission in the above-mentioned low-orbit satellite communication
  • the method when the method is applied to a terminal, may specifically include:
  • the method includes:
  • the sequence form of the PN sequence is a frequency domain PN sequence
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the frequency domain PN sequence is directly mapped onto the subcarriers.
  • the sequence form of the PN sequence is a discrete Fourier transform-extended orthogonal frequency division multiplexing DFT-s-OFDM modulated PN sequence
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain is mapped onto the subcarriers.
  • the sequence form of the PN sequence is a frequency domain PN sequence associated with a walsh orthogonal code
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the frequency domain PN sequence associated with the walsh orthogonal code is directly mapped onto the subcarriers.
  • the sequence form of the PN sequence is a PN sequence modulated by an orthogonal frequency division multiplexing DFT-s-OFDM modulated by a discrete Fourier transform associated with a walsh orthogonal code;
  • the mapping of the PN sequence to the subcarriers according to a preset transformation method includes:
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain and associated with the walsh orthogonal code is mapped onto the subcarriers.
  • the DFT-s-OFDM modulated PN sequence transformed into the frequency domain is mapped to the subcarriers Before going on, it also includes:
  • Windowing is performed on the DFT-s-OFDM modulated PN sequence transformed to the frequency domain.
  • the DFT associated with the walsh orthogonal code transformed to the frequency domain -The PN sequence modulated by s-OFDM, before being mapped to the subcarriers, further includes:
  • Windowing is performed on the DFT-s-OFDM modulated PN sequence transformed to the frequency domain and associated with the walsh orthogonal code.
  • the transmitting to the base station in a predetermined form includes:
  • the PN sequence converted to the time domain is transmitted to the base station in the form of ZP before it and GT after it, the ZP is an empty field, and the length of the ZP is 1 ⁇ 1 of the CP length of the OFDM symbol in the data area. 2 times.
  • the method when applied to a base station, may include:
  • each PN sequence in the set sequence form in the set PN sequence set with the time-frequency resource data to detect peaks in the time-frequency resource data;
  • the PN sequence in the form of the set sequence that is currently correlated with the time-frequency resource data is determined as the PN sequence sent by the terminal.
  • the PN sequences in the set sequence form in the set PN sequence set are respectively correlated with the time-frequency resource data, including:
  • Each PN sequence subsection of the PN sequence in each set sequence form is respectively correlated with the time domain resource data, and the correlation includes time domain sliding correlation and frequency domain correlation.
  • An embodiment of the present invention also provides an electronic device, the schematic structural diagram of which is shown in FIG. 7 , and specifically includes a memory 601 and one or more programs 602 , wherein one or more programs 602 are stored in the memory 601 and are processed through the memory 601 .
  • the one or more programs 602, configured to be executed by one or more processors 603, include instructions for:
  • the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solutions of the present invention can be embodied in the form of software products in essence or the parts that make contributions to the prior art.
  • the computer software products can be stored in storage media, such as ROM/RAM, magnetic disks, etc. , CD, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

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Abstract

本发明提供了一种低轨卫星通信中的随机接入信道传输方法及装置，包括：在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；将所述PN序列按预设的变换方式映射到子载波上；对映射有所述PN序列的所述子载波，做快速傅里叶逆变换，将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。本发明提供的方法，采用已设定序列形式的PN序列对需要传输的信号承载，替换现有Preamble序列采用的ZC序列，避免了在传输过程中出现伪峰的情况，能够更加有效的识别主峰，使终端可以及时接入基站，使基站有效的对信号进行接收。本发明实施例提供的方法中，采用PN序列可以在发射至基站时，不需要发射CP，节省时间开销。

Description

低轨卫星通信中的随机接入信道传输方法及装置 技术领域
本发明涉及低轨卫星通信领域，特别涉及一种低轨卫星通信中的随机接入信道传输方法及装置。
背景技术
随着通信技术的发展，人们对于信息实时性的需求越来越高。卫星通信依靠其覆盖范围广、通信容量大、传输质量好等众多优点，已经成为全球通信必不可少的重要手段。
在卫星通信中的随机接入信道PRACH主要用于估计用户接入的时候的上行传输定时误差、估计上行频偏误差及估计SNR。卫星信道的信道特点是，卫星波束的覆盖范围非常大，有60km*1000km的面积，没有上行定时之前，上行的定时误差会非常大；而且卫星通信的运动速度和采用的载频，会导致上行频偏误差也非常大，残留的上行频偏有约±30kHz；还有卫星通信的信噪比较低，最低可达-10dB。
而PRACH的发射功率会比其他信道的发射功率低，通常比PUSCH要低十多dB。
由于卫星通信存在经常切换的问题，会需要经常发射PRACH，所以PRACH设计的合理性非常重要。
现有PRACH的信道结构包含三部分，包含3部分，CP、Preamble和GT三部分。其中，CP用于抵消各用户不同时到达带来的干扰，Preamble是随机接入序列，GT用于防止Preamble干扰到后续进行传输的信号。现有的Preamble序列采用ZC(Zadoff-Chu)序列对需要传输的信号进行承载。经过对现有传输过程进行研究发现，ZC序列会在存在频偏的时候出现伪峰，当频偏超过子载波间隔的一半的时候，伪峰的能量甚至比主峰的能量大，导致无法确定传输信号的主峰，无法有效对信号进行接收。
卫星通信的频偏高达±30kHz，在这种频偏下，即便采用60kHz的子载波间隔的Preamble配置，也有无法正确判断主峰的情况。同时，当子载波间隔较大的时候，占用的频域RB也越多，导致用于PRACH的开销也增大。比如子载波间隔30kHz占用18个RB；子载波间隔60kHz占用35个RB。
发明内容
本发明所要解决的技术问题是提供一种低轨卫星通信中的随机接入信道传输方法，采用设定形式的PN序列对需要传输的信号进行承载，避免了在传输过程中出现伪峰的情况，可以直接确定传输信号的主峰，使得终端可以及时接入基站，进而有效对信号进行接收。
本发明还提供了一种低轨卫星通信中的随机接入信道传输装置，用以保证上述方法在实际中的实现及应用。
一种低轨卫星通信中的随机接入信道传输方法，所述方法应用于终端，所述方法包括：
在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；
将所述PN序列按预设的变换方式映射到子载波上；
对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
上述的方法，可选的，若所述PN序列的序列形式为频域PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
将所述频域PN序列直接映射到所述子载波上。
上述的方法，可选的，若所述PN序列的序列形式为离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
对所述DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将所述DFT-s-OFDM调制的PN序列变换到频域；
将变换到频域的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
上述的方法，可选的，若所述PN序列的序列形式为关联有walsh正交码的频域PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
将关联有walsh正交码的频域PN序列，直接映射到所述子载波上。
上述的方法，可选的，若所述PN序列的序列形式为关联有walsh正交码的离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
对所述关联有walsh正交码的DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域；
将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
上述的方法，可选的，在将所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的所述DFT-s-OFDM调制的PN序列映射到所述子载波上之前，还包括：
对变换到频域的所述DFT-s-OFDM调制的PN序列进行加窗处理。
上述的方法，可选的，在将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上之前，还包括：
对变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列进行加窗处理。
上述的方法，可选的，所述以预定的形式发射至基站，包括：
将变换至时域的PN序列，以其之前设置有ZP，其之后设置有GT的形式发射至基站，所述ZP为空字段，所述ZP的长度为数据区OFDM符号的CP长度的1～2倍。
一种低轨卫星通信中的随机接入信道传输装置，所述装置应用于终端，所述装置包括：
选取单元，用于在已设置的PN序列集合中，选取一种已设定形式的PN序列；
映射单元，用于将所述PN序列按预设的变换方式映射到子载波上；
发射单元，用于对映射有所述PN序列的所述子载波，做快速傅里叶逆变 换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
一种低轨卫星通信中的随机接入信道传输方法，所述方法应用于基站，所述方法包括：
获取时频资源数据；
将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
上述的方法，可选的，所述将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，包括：
将所述已设置的PN序列集合中的各个已设定序列形式的PN序列，划分为多个PN序列子段；
将每个已设定序列形式的PN序列的各个PN序列子段分别与所述时域资源数据进行相关，所述相关包括时域滑动相关和频域相关。
一种低轨卫星通信中的随机接入信道传输装置，所述装置应用于基站，包括：
获取单元，用于获取时频资源数据；
检测单元，用于将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
确定单元，用于当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
与现有技术相比，本发明包括以下优点：
本发明提供了一种低轨卫星通信中的随机接入信道传输方法，包括：在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；将所述PN序列按预设的变换方式映射到子载波上；对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。本发明提供的随机接入信道传输方法，采用已设定 序列形式的PN序列对需要传输的信号进行承载，替换现有Preamble序列采用的ZC序列，避免了在传输过程中出现伪峰的情况，能够更加有效的识别主峰，使得终端可以及时接入基站，使基站有效的对信号进行接收。本发明实施例提供的方法中，采用PN序列，可以在发射至基站时，不需要发射CP，进而节省时间开销。
附图说明
为了更清楚地说明本发明实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本发明提供的一种低轨卫星通信中的随机接入信道传输方法的方法流程图；
图2为本发明提供的一种低轨卫星通信中的随机接入信道传输装置的结构示意图；
图3为本发明提供的一种低轨卫星通信中的随机接入信道传输方法的另一方法流程图；
图4为本发明提供的一种低轨卫星通信中的随机接入信道传输方法的另一结构示意图；
图5为本发明提供的一种低轨卫星通信中的随机接入信道传输系统的结构示意图；
图6为本发明提供的一种低轨卫星通信中的随机接入信道传输系统的通信原理图；
图7为本发明提供的一种电子设备的结构示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是 全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明可用于众多通用或专用的计算装置环境或配置中。例如：个人计算机、服务器计算机、手持设备或便携式设备、平板型设备、多处理器装置、包括以上任何装置或设备的分布式计算环境等等。
本发明实施例提供了一种低轨卫星通信中的随机接入信道传输方法，所述方法的执行主体可以为终端中的处理器，本发明实施例提供的低轨卫星通信中的随机接入信道传输方法的方法流程图如图1所示，包括：
S101：在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；
本发明实施例提供的方法中，设置有PN序列集合，所述PN序列集合中设置有多个已设定序列形式的PN序列，所述PN序列集合中的每个PN序列的已设定形式相同。所述PN序列集合中的PN序列可以设定多种不同的序列形式。本发明实施例提供的方法中，基站及各个终端均可以读取所述PN序列集合中的各个已设定序列形式的PN序列。终端在需要进行随机接入信道传输时，可以在所述PN序列集合中选取一种已设定序列形式的PN序列，实际的选取过程，可以根据需要传输的数据类型对PN序列集合中的各个PN序列的序列形式进行设定后，再随机选取。
S102：将所述PN序列按预设的变换方式映射到子载波上；
本发明实施例提供的方法中，针对随机接入信道所采用的CP，Preamble序列，GT的组成，采用在PN序列集合中选取的PN序列代替Preamble序列中原有的ZC序列，在随机接入信道传输过程中，将选取的PN序列按预设的变换方式，映射到子载波上。
S103：对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
本发明实施例提供的方法，在随机接入信道传输的过程中，需要将映射有PN序列的子载波做快速傅里叶逆变换，将映射有PN序列的子载波变换到时域，获得在映射有PN序列的子载波在时域中对应的时频资源数据，并将所述时频资源数据以预定的形式发射至基站。
本发明实施例提供的低轨卫星通信中的随机接入信道传输方法，在终端需要接入基站，以向基站发送数据信号时，在已设置的PN序列集合中选择一种已设定序列形式的PN序列作为随机接入信道中Preamble序列的信号承载序列，将选取的PN序列按一定的变换方式映射到子载波上，然后对映射有PN序列的子载波做快速傅里叶逆变换，将该子载波变换到时域，并将变换至时域的时频资源数据以预定的形式发射至基站，以实现应用随机接入信道进行传输的过程，该过程中，采用已设定形式的PN序列作为信号的承载序列，避免了接入过程中出现伪峰的情况，能够准确识别数据主峰，使得终端可以及时接入基站，实现了对信号的有效传输。
本发明实施例提供的方法，在对现有的随机接入信道传输过程进行研究的基础上实现，现有的实现过程中，Preamble序列采用的ZC序列会在存在频偏的时候出现伪峰，当频偏超过子载波间隔的一半的时候，伪峰的能量甚至比主峰的能量要大。即便频偏等于子载波间隔的一半，如果有定时偏差、加性高斯白噪声、相位噪声等情况，也会出现伪峰的能量比主峰的能量低。卫星通信的频偏高达±30kHz，在这种频偏下，即便采用60kHz的子载波间隔的Preamble配置，也有无法正确判断主峰的情况。同时，当子载波间隔较大的时候，占用的频域RB也越多，导致用于PRACH的开销也增大。比如子载波间隔30kHz占用18个RB；子载波间隔60kHz占用35个RB。
在上述技术背景的前提下，本发明实施例提供的低轨卫星通信中的随机接入信道传输方法中，采用PN序列代替Preamble序列中的ZC序列，本发明实施例提供的方法中，预先设置PN序列集合，所述PN序列集合中设置有预设数量的PN序列，所述PN序列集合中的各个PN序列的序列形式相同，例如PN序列集合中的各个PN序列的序列形式均为频域PN序列。PN序列集合中的各个PN序列的序列内容各不相同。本发明实施例提供的PN序列集合可以设置在终端中，也可以设置在基站中，优选的可以设置在本地第三方系统中，终端及基站均可以对所述PN序列集合进行访问。
本发明实施例提供的方法中，可以为PN序列集合中的各个PN序列设定多种序列形式，优选的，本发明实施例提供的方法中，设定有四种不同序列形式的PN序列集合，分别可以为：
PN序列的序列形式为频域PN序列；
PN序列的序列形式为离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
PN序列的序列形式为关联有walsh正交码的频域PN序列；
PN序列的序列形式为关联有walsh正交码的离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列。
上述四种序列形式的PN序列分别对应四个PN序列集合，在具体的随机接入信道传输过程中，可以根据实际需要传输的数据信号的类型进行设置。
本发明实施例提供的随机接入信道传输方法，在采用频域PN序列时，由于PRACH的发射功率较低，所以在一定程度上可以认为频域PN序列带来的时域峰均比问题可以接受。因此在实际的传输过程中，需要将已设定形式的PN序列以频域的形式按一定的方式映射到子载波上。在采用DFT-s-OFDM调制的PN序列或采用DFT-s-OFDM调制的PN序列+walsh码的组合时，峰均比是相对比较低的，在本方提供的方案中，对随机接入信道传输的影响可以忽略。
在具体的实现过程中，当选取的PN序列的序列形式为频域PN序列时，所述将所述PN序列按预设的变换方式映射到子载波上，包括：
将所述频域PN序列直接映射到所述子载波上。
本发明实施例提供的方法中，在同一个PRACH时频资源支持多个用户用不同的PN序列进行随机接入。对于频域PN序列可以直接映射到其对应的子载波上。此过程适用于本发明实施例提供的四种不同序列形式的PN序列，在变换至频域后，可以允许多个用户的PN序列进行随机接入。
在实际的实现过程中，本发明实施例提供的方法中，当PN序列的序列形式为频域PN序列时，所述PN序列集合中可以设置64种PN序列，每种PN序列使用不同的序列初始化ID，每种PN序列均为512点。
终端在发射过程中，可以在64种PN序列中挑选一种PN序列，映射到30kHz间隔的对应的子载波上，一共占用12个RB位置，然后做IFFT变换到时域发射出去。
本发明实施例提供的方法中，在将频域PN序列映射到所述子载波上之前， 可以对所述频域PN序列进行加窗处理，所述加窗处理可以为加汉明窗或根升余弦窗等。
本发明实施例提供的方法中，所述子载波可以理解为传输过程中选取的PN序列所对应的子载波。
在具体的实现过程中，当所述PN序列的序列形式为离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列时；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
对所述DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将所述DFT-s-OFDM调制的PN序列变换到频域；
将变换到频域的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
本发明实施例提供的方法中，当PN序列中的各个PN序列的序列形式为DFT-s-OFDM调制的PN序列时，所述PN序列集合中可以设置64种PN序列，每种PN序列的序列形式为DFT-s-OFDM调制的PN序列，每种PN序列使用不同的序列初始化ID，每种PN序列均为512点。
终端在发射过程中，可以在64种PN序列中挑选一种PN序列，然后做512点的快速傅里叶变换FFT，以将所述DFT-s-OFDM调制的PN序列变换到频域，然后映射到30kHz间隔的对应的子载波上，一共占用12个RB位置。本发明实施例提供的方法中，为减少对其它子载波的PUSCH的干扰，可以在将所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的所述DFT-s-OFDM调制的PN序列映射到所述子载波上之前，对变换到频域的所述DFT-s-OFDM调制的PN序列进行加窗处理。
所述加窗处理可以为加汉明窗或根升余弦窗等，然后做IFFT变换到时域发射出去。
本发明实施例提供的方法中，若所述PN序列的序列形式为关联有walsh正交码的频域PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
将关联有walsh正交码的频域PN序列，直接映射到所述子载波上。
本发明实施例提供的方法中，所述频域PN序列与所述walsh正交码的关联方式可以为频域PN序列+walsh正交码的形式。
在频域PN序列+walsh正交码的形式下，可以设置4种频域PN序列，每种频域PN序列使用不同的序列初始化ID，每种PN序列均为512点。并设置16个长度为16的walsh码，频域PN序列和walsh码的组合一共有64种，该PN序列集合中有64种关联有walsh正交码的频域PN序列。
终端在发射过程中，可以在64种频域PN序列+walsh码的组合中挑选一种，映射到30kHz间隔的对应的子载波上，一共占用12个RB位置，然后做IFFT变换到时域发射出去。所述频域PN序列+walsh码的序列形式可以直接映射到该PN序列对应的子载波上。
本发明实施例提供的方法中，在将频域PN序列+walsh码的组合映射到所述子载波上之前，可以对所述频域PN序列+walsh码的组合进行加窗处理，所述加窗处理可以为加汉明窗或根升余弦窗等。
本发明实施例提供的方法中，当所述PN序列的序列形式为关联有walsh正交码的离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列时；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
对所述关联有walsh正交码的DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域；
将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
本发明实施例提供的方法中，所述DFT-s-OFDM调制的PN序列与所述walsh正交码的关联方式可以为DFT-s-OFDM调制的PN序列+walsh码的形式。
在DFT-s-OFDM调制的PN序列+walsh码的形式下，可以设置4种DFT-s-OFDM调制的PN序列，每种DFT-s-OFDM调制的PN序列使用不同的序列初始化ID。每种DFT-s-OFDM调制的PN序列均为512点，并设置16个长度为16的walsh码。DFT-s-OFDM调制的PN序列和walsh码的组合一共有64种。该PN序列集合中包含有64种关联有walsh码的DFT-s-OFDM调制的PN序列。
终端在发射过程中，可以在64种DFT-s-OFDM调制的PN序列+walsh码的组合中挑选一种，然后做512点的FFT，将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域，映射到30kHz间隔对应的子载波上，一共占用12个RB位置。
本发明实施例提供的方法中，在DFT-s-OFDM调制的PN序列+walsh码的形式下，为了减少对其它子载波的PUSCH的干扰，可以在将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上之前，对变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列进行加窗处理。
所述加窗处理可以为加汉明窗或者根升余弦窗等。
在进行加窗处理后，做IFFT变换到时域发射出去。
在现有Preamble序列采用基于OFDM的ZC序列的背景下，ZC序列需要CP长度，这里的CP长度较长，30kHz下的CP是Preamble符号重复3次，60kHz是Preamble符号重复12次。而每出现一次Preamble符号，都会有主峰和伪峰出现，最终的结果是会出现很多的峰值，增加首峰判断的难度，以及多用户峰值分辨的难度。因此，本发明实施例提供的随机接入信道传输方法中，无论应用哪种序列形式的PN序列进行传输，在将PN序列映射到子载波，并发射出去的这一过程中，可以不需要CP，但在Preamble符号前加ZP(Zero-Padding)，ZP即什么都不发，长度可以是数据区OFDM符号的CP长度的1～2倍，例如，卫星通信协议中数据区的OFDM符号的CP是0.59us，Preamble的OFDM符号的CP是200us，则ZP的长度为0.59us～1.18us。ZP的作用是避免其他用户的上行符号的延时对本用户Preamble符号的干扰。因为其他用户发射上行符号时已经进行了上行同步，所以延时一般不超过普通OFDM符号的CP长度，所以ZP的长度设置为数据区OFDM符号的CP长度的1～2倍。
本发明实施例提供的方法中，保留GT以避免对后续信号符号的干扰。
综上所述，本发明实施例提供的方法中，所述以预定的形式发射至基站，包括：
将变换至时域的PN序列，以其之前设置有ZP，其之后设置有GT的形式发射至基站，所述ZP为空字段，所述ZP的长度为数据区OFDM符号的CP长度的1～2倍。
本发明实施例提供的方法中，在将选取的PN序列变换至时域后，获得选取的PN序列变换至时域后的时频资源数据，并在所述时频资源数据之前设置ZP，所述时频资源数据之后设置GT，发送至基站。
本发明实施例提供的方法中，采用PN序列后，不需要时间开销较大的PreambleCP，只需要时间较小的ZP，节省了时间开销。
与图1所述的方法相对应，本发明实施例还提供了一种低轨通信卫星中的随机接入信道传输装置，用于对图1中方法的具体实现，本发明实施例提供的随机接入信道传输装置可以应用在计算机终端或各种移动设备中，其结构示意图如图2所示，所述装置包括：
选取单元201，用于在已设置的PN序列集合中，选取一种已设定形式的PN序列；
映射单元202，用于将所述PN序列按预设的变换方式映射到子载波上；
发射单元203，用于对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
本发明实施例提供的本发明实施例提供的低轨卫星通信中的随机接入信道传输装置，在终端需要向基站发送数据信号时，在已设置的PN序列集合中选择一种已设定序列形式的PN序列作为随机接入信道中Preamble序列的信号承载序列，将选取的PN序列按一定的变换方式映射到子载波上，然后对映射有PN序列的子载波做快速傅里叶逆变换，将该子载波变换到时域，并将变换至时域的时频资源数据以预定的形式发射至基站，以实现应用随机接入信道进行传输的过程，该过程中，采用已设定形式的PN序列作为信号的承载序列，避免了传输过程中出现伪峰的情况，能够准确识别数据主峰，使得终端可以及时接入基站，使基站有效的对信号进行接收，实现了对信号的有效传输。
参考图3，本发明实施例还提供了一种低轨卫星通信中的随机接入信道传 输方法在基站方的实现过程，在基站方实现的随机接入信道的传输方法的执行主体可以为基站处的处理器，该处理器可以对已设置的PN序列集合中的各个PN序列进行读取，所述方法包括：
S301：获取时频资源数据；
本发明实施例提供的方法中，当终端将时域信号发送至基站时，基站方获取终端发送的时频资源数据，所述时频资源数据为终端方选取的PN序列映射到时域后对应的时频资源数据，所述时频资源数据后设置有GT。
S302：将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
本发明实施例提供的方法中，基站方的处理器，在已设置的PN序列集合中逐一读取所述PN序列集合中的各个已设定序列形式的PN序列，并将读取的每个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值。需要说明的是，基站方所读取的PN序列集合与终端方所读取的PN序列集合为同一PN序列集合。
S303：当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
本发明实施例提供的方法中，在检测到时频资源数据中的峰值时，即可以确定当前与所述时频资源数据进行相关的已设定序列形式的PN序列为终端所采用的PN序列，进而可以允许该终端接入基站。
本发明实施例提供的低轨卫星通信中的随机接入信道传输方法，在基站方，获取到终端方发送的时频资源数据后，通过获取已设置PN序列集合中各个已设定形式的PN序列，并将获取的各个PN序列进行相关的方式，检测时频资源数据中的峰值，进而确定终端侧所采用的PN序列，以允许终端通过该PN序列接入基站，实现基站对信号的有效接收。
本发明实施例提供的方法中，所述将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，包括：
将所述已设置的PN序列集合中的各个已设定序列形式的PN序列，划分为多个PN序列子段；
将每个已设定序列形式的PN序列的各个PN序列子段分别与所述时域资源 数据进行相关，所述相关包括时域滑动相关和频域相关。
为了更加详细的对上述峰值检测的过程进行描述，本发明实施例提供以下实例，对相关的过程进行详细说明：
第一个实例
当终端在PN序列集合中选取的PN序列的已设定格式，为频域PN序列时，基站方执行以下操作：
基站的接收端截取Preamble符号+GT长度(ZP部分数据不截取)，获得对应时频资源的数据，并遍历本地64种PN序列，每一种PN序列均与接收到的PRACH数据做分段相关，如分段数为4，即把512点数据分为4段128点的数据分别和发射数据进行相关。其中相关可以为时域滑动相关和频域相关两种。当检索到峰值即可获得终端所发送的PN序列及对应的定时偏差TO位置。通过峰值对应的4段相关值的相位差即可计算得到频率偏差FO。
具体的实现过程如下：
假设基站接收到的PRACH时域信号为，设长度为(含Preamble符号+GT长度)，本地的某一种PN频域序列对应的时域序列为(为PN频域序列的IFFT变换)。
PN序列的已设定形式为频域PN序列时的时域分段相关法为：
计算，寻找中的有效峰值，如果出现有效峰值，那就代表有一个用户用了该PN序列发射了PRACH，设峰值位置对应的的n值为，即为对应的定时偏差TO位置。计算，频率偏差FO为。
对应的频域分段相关法见下：
设置向量，将其变换到频域，得到1*256的向量。设置向量，将其变换到频域，得到1*256的向量。接着计算，其中表示对向量的每一个元素取共轭，表示两个向量的点乘。然后将变换到时域，得到1*256的向量，取向量的前128个元素，得到1*128的向量，设里的每一个元素为。计算，寻找中的有效峰值，如果出现有效峰值，那就代表有一个用户用了该PN序列发射了PRACH，设峰值位置对应的的n值为，即为对应的定时偏差TO位置。计算，频率偏差FO为。
第二个实例
当终端在PN序列集合中选取的PN序列的已设定格式，为DFT-s-OFDM调 制的PN序列时，基站方执行以下操作：
基站接收端截取Preamble符号+GT长度(ZP部分数据不截取)，获得对应时频资源的数据，并遍历本地64种PN序列，每一种PN序列均与接收到的PRACH数据做分段相关，如分段数为4，即把512点数据分为4段128点的数据分别和发射数据进行相关。其中相关可以为时域滑动相关和频域相关两种。当检索到峰值即可获得终端所发送的PN序列及对应的定时偏差TO位置。通过峰值对应的4段相关值的相位差即可计算得到频率偏差FO。时域滑动相关和频域相关方法与第一个实例类似，此处不做赘述，本领域技术人员在第一个实例的基础上，能够理解到第二个实例的实际过程，不同点是时域序列即为本地PN序列。
第三个实例
当终端在PN序列集合中选取的PN序列的已设定格式为频域PN序列+walsh码时，基站方执行以下操作：
基站接收端截取Preamble符号+GT长度(ZP部分数据不截取)，获得对应时频资源的数据，并遍历本地64种PN序列+Walsh码的组合，每一种PN序列+Walsh码的组合均与接收到的PRACH数据做分段相关，如分段数为4，即把512点数据分为4段128点的数据分别和发射数据进行相关。其中相关可以为时域滑动相关和频域相关两种。当检索到峰值即可获得终端所发送的PN序列及对应的定时偏差TO位置。通过峰值对应的4段相关值的相位差即可计算得到频率偏差FO。时域滑动相关和频域相关方法与第一个实例类似，此处不做赘述，本领域技术人员在第一个实例的基础上，能够理解到第二个实例的实际过程，与第一个实例不同的是，第三个实例与第一个实例的码字不同。
第四个实例
当终端在PN序列集合中选取的PN序列的已设定格式为DFT-s-OFDM调制的PN序列+walsh码时，基站方执行以下操作：
基站接收端截取Preamble符号+GT长度(ZP部分数据不截取)，获得对应时频资源的数据，并遍历本地64种PN序列+Walsh码的组合，每一种PN序列 +Walsh码的组合均与接收到的PRACH数据做分段相关，如分段数为4，即把512点数据分为4段128点的数据分别和发射数据进行相关。其中相关可以为时域滑动相关和频域相关两种。当检索到峰值即可获得终端所发送的PN序列及对应的定时偏差TO位置。通过峰值对应的4段相关值的相位差即可计算得到频率偏差FO。时域滑动相关和频域相关方法与第二个实例类似，只是码字不同。
本发明实施例提供的方法中，在低轨卫星通信中使用PN序列或者PN序列+Walsh正交码作为随机接入码字。在同一个PRACH时频资源支持多个用户用不同的PN序列和Walsh正交码进行随机接入。PRACH前面不需要CP，只需要一段相对较短的ZP。
本发明实施例提供的方法中，将卫星通信协议中生成上行PRACH的序列由ZC序列改成PN序列，或者PN序列+Walsh序列，避免了ZC序列在高频偏下的多峰值问题，在多用户下极大的提升了检测成功概率、TA估计精度和频偏估计精度，并可降低PRACH信道所占用的时间长度。
本发明实施例提供的方法中，在上述第二个实例的基础上，进行仿真实验，设置频偏30kHz，SNR＝-10dB，测试过程中只出现一个峰值，估计的频偏为31.67kHz。
当设置频偏30kHz，SNR＝8dB时的峰值更为清晰，估计的频偏为30.05kHz。
可见，使用新序列，可以有效、准确地估计定时和频偏，并且只有一个峰值，检索方便。而且时域上节省了CP，频域的RB数也可以变少，有效在大时延、大频偏下节省PRACH开销。
与图3所述的方法相对应，本发明实施例还提供了一种低轨卫星通信中的随机接入信道传输装置，用于对图3中方法的具体实现，本发明实施例提供的低轨卫星通信中的随机接入信道传输装置可以应用在基站中，其结构示意图如图4所示，所述装置包括：
获取单元401，用于获取时频资源数据；
检测单元402，用于将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
确定单元403，用于当检测到所述视频资源数据中的峰值时，将当前与所 述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
本发明实施例提供的随机接入信道传输装置，在基站方，获取到终端方发送的时频资源数据后，通过获取已设置PN序列集合中各个已设定形式的PN序列，并将获取的各个PN序列进行相关的方式，检测时频资源数据中的峰值，进而确定终端侧所采用的PN序列，以允许终端通过该PN序列接入基站，实现基站对信号的有效接收。
本发明实施例提供的方法中，参考图5，还提供了一种低轨卫星通信中的随机接入信道传输系统，所述传输系统包括终端方和基站方，
所述终端方包括：
选取单元，用于在已设置的PN序列集合中，选取一种已设定形式的PN序列；
映射单元，用于将所述PN序列按预设的变换方式映射到子载波上；
发射单元，用于对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
所述基站方包括：
获取单元，用于获取时频资源数据；
检测单元，用于将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
确定单元，用于当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
本发明实施例提供的低轨卫星通信中的随机接入信道传输系统，将现有Preamble序列中的ZC序列替换为PN序列，有效的避免了传输过程中出现伪峰，导致不能准确确定主峰的问题。使终端可以及时接入基站，实现了信号的有效传输。本发明实施例提供的低轨卫星通信中的随机接入信道传输系统中终端与卫星通信的原理过程，可以参照本发明实施例提供的图6，其中，甚小口径卫 星通信终端501，通过服务链路与星载平台502进行通信，星载平台502通过馈线链路与网关连接。
本发明实施例还提供了一种存储介质，所述存储介质包括存储的程序，其中，在所述程序运行时控制所述存储介质所在的设备执行上述低轨卫星通信中的随机接入信道传输方法，所述方法应用在终端时，具体可以包括：
所述方法包括：
在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；
将所述PN序列按预设的变换方式映射到子载波上；
对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
上述的方法，可选的，若所述PN序列的序列形式为频域PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
将所述频域PN序列直接映射到所述子载波上。
上述的方法，可选的，若所述PN序列的序列形式为离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
对所述DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将所述DFT-s-OFDM调制的PN序列变换到频域；
将变换到频域的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
上述的方法，可选的，若所述PN序列的序列形式为关联有walsh正交码的频域PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
将关联有walsh正交码的频域PN序列，直接映射到所述子载波上。
上述的方法，可选的，若所述PN序列的序列形式为关联有walsh正交码的离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
所述将所述PN序列按预设的变换方式映射到子载波上，包括：
对所述关联有walsh正交码的DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域；
将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
上述的方法，可选的，在将所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的所述DFT-s-OFDM调制的PN序列映射到所述子载波上之前，还包括：
对变换到频域的所述DFT-s-OFDM调制的PN序列进行加窗处理。
上述的方法，可选的，在将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上之前，还包括：
对变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列进行加窗处理。
上述的方法，可选的，所述以预定的形式发射至基站，包括：
将变换至时域的PN序列，以其之前设置有ZP，其之后设置有GT的形式发射至基站，所述ZP为空字段，所述ZP的长度为数据区OFDM符号的CP长度的1～2倍。
所述方法，应用在基站时，可以包括：
获取时频资源数据；
将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
上述的方法，可选的，所述将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，包括：
将所述已设置的PN序列集合中的各个已设定序列形式的PN序列，划分为多个PN序列子段；
将每个已设定序列形式的PN序列的各个PN序列子段分别与所述时域资源数据进行相关，所述相关包括时域滑动相关和频域相关。
本发明实施例还提供了一种电子设备，其结构示意图如图7所示，具体包 括存储器601，以及一个或者一个以上的程序602，其中一个或者一个以上程序602存储于存储器601中，且经配置以由一个或者一个以上处理器603执行所述一个或者一个以上程序602包含用于进行以下操作的指令：
在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；
将所述PN序列按预设的变换方式映射到子载波上；
对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
需要说明的是，本说明书中的各个实施例均采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似的部分互相参见即可。对于装置类实施例而言，由于其与方法实施例基本相似，所以描述的比较简单，相关之处参见方法实施例的部分说明即可。
最后，还需要说明的是，在本文中，诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来，而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。
为了描述的方便，描述以上装置时以功能分为各种单元分别描述。当然，在实施本发明时可以把各单元的功能在同一个或多个软件和/或硬件中实现。
通过以上的实施方式的描述可知，本领域的技术人员可以清楚地了解到本发明可借助软件加必需的通用硬件平台的方式来实现。基于这样的理解，本发明的技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品可以存储在存储介质中，如ROM/RAM、磁碟、光盘等，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本发明各个实施例或者实施例的某些部分所述的方法。
以上对本发明所提供的一种低轨卫星通信中的随机接入信道传输方法及装置进行了详细介绍，本文中应用了具体个例对本发明的原理及实施方式进行 了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本发明的限制。

Claims (12)

  1. 一种低轨卫星通信中的随机接入信道传输方法，其特征在于，所述方法应用于终端，所述方法包括：
    在已设置的PN序列集合中，选取一种已设定序列形式的PN序列；
    将所述PN序列按预设的变换方式映射到子载波上；
    对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
  2. 根据权利要求1所述的方法，其特征在于，若所述PN序列的序列形式为频域PN序列；
    所述将所述PN序列按预设的变换方式映射到子载波上，包括：
    将所述频域PN序列直接映射到所述子载波上。
  3. 根据权利要求1所述的方法，其特征在于，若所述PN序列的序列形式为离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
    所述将所述PN序列按预设的变换方式映射到子载波上，包括：
    对所述DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将所述DFT-s-OFDM调制的PN序列变换到频域；
    将变换到频域的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上。
  4. 根据权利要求1所述的方法，其特征在于，若所述PN序列的序列形式为关联有walsh正交码的频域PN序列；
    所述将所述PN序列按预设的变换方式映射到子载波上，包括：
    将关联有walsh正交码的频域PN序列，直接映射到所述子载波上。
  5. 根据权利要求1所述的方法，其特征在于，若所述PN序列的序列形式为关联有walsh正交码的离散傅里叶变换扩展的正交频分复用DFT-s-OFDM调制的PN序列；
    所述将所述PN序列按预设的变换方式映射到子载波上，包括：
    对所述关联有walsh正交码的DFT-s-OFDM调制的PN序列，进行快速傅里叶变换，以将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域；
    将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列， 映射到所述子载波上。
  6. 根据权利要求3所述的方法，其特征在于，在将所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的所述DFT-s-OFDM调制的PN序列映射到所述子载波上之前，还包括：
    对变换到频域的所述DFT-s-OFDM调制的PN序列进行加窗处理。
  7. 根据权利要求5所述的方法，其特征在于，在将关联有walsh正交码的所述DFT-s-OFDM调制的PN序列变换到频域之后，将变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列，映射到所述子载波上之前，还包括：
    对变换到频域的关联有walsh正交码的所述DFT-s-OFDM调制的PN序列进行加窗处理。
  8. 根据权利要求1所述的方法，其特征在于，所述以预定的形式发射至基站，包括：
    将变换至时域的PN序列，以其之前设置有ZP，其之后设置有GT的形式发射至基站，所述ZP为空字段，所述ZP的长度为数据区OFDM符号的CP长度的1～2倍。
  9. 一种低轨卫星通信中的随机接入信道传输装置，其特征在于，所述装置应用于终端，所述装置包括：
    选取单元，用于在已设置的PN序列集合中，选取一种已设定形式的PN序列；
    映射单元，用于将所述PN序列按预设的变换方式映射到子载波上；
    发射单元，用于对映射有所述PN序列的所述子载波，做快速傅里叶逆变换IFFT，以将映射有所述PN序列的所述子载波变换到时域，并以预定的形式发射至基站。
  10. 一种低轨卫星通信中的随机接入信道传输方法，其特征在于，所述方法应用于基站，所述方法包括：
    获取时频资源数据；
    将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
    当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
  11. 根据权利要求10所述的方法，其特征在于，所述将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，包括：
    将所述已设置的PN序列集合中的各个已设定序列形式的PN序列，划分为多个PN序列子段；
    将每个已设定序列形式的PN序列的各个PN序列子段分别与所述时域资源数据进行相关，所述相关包括时域滑动相关和频域相关。
  12. 一种低轨卫星通信中的随机接入信道传输装置，其特征在于，所述装置应用于基站，包括：
    获取单元，用于获取时频资源数据；
    检测单元，用于将已设置的PN序列集合中的各个已设定序列形式的PN序列分别与所述时频资源数据进行相关，以检测所述时频资源数据中的峰值；
    确定单元，用于当检测到所述时频资源数据中的峰值时，将当前与所述时频资源数据进行相关的所述已设定序列形式的PN序列确定为终端发送的PN序列。
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