WO2007101382A1 - Procédé et système mixtes de multiplexage par répartition orthogonale de la fréquence à étalement du spectre - Google Patents

Procédé et système mixtes de multiplexage par répartition orthogonale de la fréquence à étalement du spectre Download PDF

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Publication number
WO2007101382A1
WO2007101382A1 PCT/CN2007/000058 CN2007000058W WO2007101382A1 WO 2007101382 A1 WO2007101382 A1 WO 2007101382A1 CN 2007000058 W CN2007000058 W CN 2007000058W WO 2007101382 A1 WO2007101382 A1 WO 2007101382A1
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WIPO (PCT)
Prior art keywords
signal
spread spectrum
unit
ofdm
channel
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PCT/CN2007/000058
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English (en)
French (fr)
Inventor
Ruobin Zheng
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Huawei Technologies Co., Ltd.
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Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Publication of WO2007101382A1 publication Critical patent/WO2007101382A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0016—Time-frequency-code
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0091—Signaling for the administration of the divided path

Definitions

  • the present invention relates to the field of communications, and in particular, to a spread spectrum OFDM (orthogonal frequency division multiplexing) hybrid system and method.
  • OFDM orthogonal frequency division multiplexing
  • Spread Spectrum Communication is a technique in which the original information band is broadened to transmit the original information over a wider frequency band, and the original information band is restored at the receiving end by the associated receiving technique.
  • the methods of spread spectrum communication mainly include: direct sequence spread spectrum (DS: direct sequence spread spectrum), frequency hopping spread spectrum (FH: frequency Hopping), time hopping (TH: Time Hopping), chirp (Chirp) .
  • the direct sequence spread spectrum described above directly spreads the spectrum of the original information signal at the transmitting end by using the high-rate pseudo-random spreading code PN sequence, and then transmits the spread spectrum signal to the receiving end.
  • the spread spectrum signal received by the same spreading code PN sequence is despread, and the spread spread spectrum signal is restored to the original information signal.
  • the despreading of the receiver is actually to broaden the spectrum of the interfering signal.
  • the interfering signal is converted into a signal with a low power spectral density and a wide spectrum. After filtering through the narrow-band filter, the energy of the interfering signal falling into the band is small. And the useful digital signal is compressed back into a narrowband signal that passes through the filter.
  • a method of spread spectrum modulation in the system is to add or multiply the information sequence and the pseudo-random sequence directly by modulo 2 to generate a rate and A pseudo-random sequence spread spectrum sequence with the same code rate.
  • Spread spectrum communication has the following advantages: (1) low spectral density, low electromagnetic interference to other systems; (2) strong anti-interference and low bit error rate; (3) information confidentiality; (4) code score can be realized Multiple access.
  • the minimum bit-output signal-to-noise ratio of the modulation is less than 10. 5dB
  • the system can be at the interference input power level ratio
  • the frequency signal power level is high in the range of 16.5dB, that is, the system can work normally in the environment where the receiving input signal-to-noise ratio is greater than or equal to -16. 5dB.
  • the interference tolerance is expanded by uncoded DS.
  • the frequency system is obtained, so the interference tolerance can also be increased by using the information sequence coding.
  • the basic principle of 0FDM is to convert the encoded serial data into parallel data. Then, the parallel data is separately modulated by N carriers with equal intervals, and the signals of the N subcarriers obtained after modulation are added. Then send simultaneously, so that the spectrum of each subcarrier symbol only accounts for a small part of the available channel bandwidth. By selecting the carrier spacing, These subcarriers are kept orthogonal in spectrum over the entire symbol period, and the signals on the subcarriers overlap each other in the spectrum. The receiving end can recover the transmitted information without distortion by using the orthogonality between the carriers. OFDM can be realized by an IFFT (Inversed Fast Fourier Transform) / FFT (Fast Fourier Transform) pair.
  • IFFT Inversed Fast Fourier Transform
  • FFT Fast Fourier Transform
  • OFDM communication has the following advantages: (1) Spectrum utilization ⁇ , theoretically can meet the limits of Shannon information theory; (2) can effectively overcome ISI (Intersymbol Interference); (3) can effectively resist channel fading. OFDM technology divides the frequency selective fading channel into multiple parallel related flat fading channels. Therefore, simple channel equalization technology can meet the system performance requirements, and complex adaptive equalization techniques are not needed. (4) Noise interference, the interference of OFDM to channel noise interference is achieved by subchannel allocation. (5) Suitable for high speed data transmission.
  • the OFDM adaptive modulation scheme allows different subcarriers to use different modulation schemes depending on channel conditions and noise background.
  • a highly efficient modulation method is employed.
  • a modulation method with strong anti-interference ability is adopted.
  • the use of the OFDM loading algorithm allows the system to place more data sets on a well-conditioned channel for transmission at a high rate. Therefore, OFDM technology is well suited for high speed data transmission.
  • CDMA code division multiple access
  • the RF bandwidth requirement of CDMA is much larger than the data rate to ensure sufficient processing gain to resist interference.
  • CDMA code division multiple access
  • the RF bandwidth needs to exceed 200 MHz to maintain sufficient processing gain and NL0S (Non Line-of- Sight, non-line-of-sight propagation) Communication performance.
  • broadband wireless access technology is booming, and the technology of using broadband resources to carry out broadband metro access has strong vitality and market space.
  • the spectrum resources of the wireless are very valuable, especially in areas where there are no well-planned spectrum resources or unlicensed frequency bands, and there are often multiple base stations operating on the same channel, resulting in the interconnection of multiple base stations. Interfere with each other.
  • the neighboring base stations need to negotiate with each other to solve the problem of coexistence in the same frequency band or adjacent frequency band.
  • a method for solving the problem of coexistence between base stations in the prior art is: defining a "coexistence negotiation dedicated time slice" in a downlink subframe of a frame format of the original base station system, and using the "coexistence negotiation dedicated time” between adjacent base stations The film "negotiated to solve the problem of coexistence in the same band or adjacent band.
  • the "coexistence negotiation dedicated time slice” is divided into the frame format of the original base station system, which occupies a scarce wireless communication resource of the base station system to a certain extent, and the base station system cannot perform normal service communication at the time slice. This is especially true when the negotiation signaling traffic is large. Summary of the invention
  • a spread spectrum orthogonal frequency division multiplexing hybrid system comprising: an orthogonal frequency division multiplexing OFDM transmitter and a spread spectrum transmitter, and an orthogonal frequency division multiplexing OFDM transmitter: performing orthogonal frequency division on the first signal Obtaining an OFDM communication signal by processing, and transmitting, by the transmitting antenna, the OFDM communication signal on a frequency band shared by the transmitting and transmitting machine;
  • the second signal is subjected to spread spectrum modulation processing to obtain a spread spectrum communication signal, and the spread spectrum communication signal is transmitted through a frequency band shared by the transmitting antenna and the OFDM transmitter.
  • a spread spectrum orthogonal frequency division multiplexing hybrid method comprising:
  • the first signal is subjected to orthogonal frequency division multiplexing processing to obtain an OFDM communication signal
  • the second signal is subjected to spread spectrum modulation processing to obtain a spread spectrum communication signal
  • the spread spectrum communication signal and the OFDM communication signal are jointly occupied by the transmitting antenna. Simultaneous transmission on the frequency band.
  • the embodiment of the present invention combines the 0FDM and the spread spectrum communication technology, and processes the signaling signal through the spread spectrum communication channel, and passes the normal communication data through the 0FDM communication channel. Process it. Compared with the prior art, it has the following advantages:
  • the power spectral density of the spread spectrum signal of the spread spectrum communication channel can be much smaller than the signal power spectral density of the 0FDM communication channel.
  • the spread spectrum communication channel can transmit signaling signals at a power much lower than the 0FDM communication channel, so that the spread spectrum communication channel signal does not interfere with the 0FDM communication channel signal; at the receiving end, the spread spectrum communication channel can even be in the signal Fully submerged in the presence of noise, ie when the power spectral density of the spread spectrum signal of the received spread spectrum communication channel is lower than the power spectral density of the channel noise (including the front-end thermal noise of the receiver and the additive noise in the channel) The spread spectrum communication channel receiver can still work normally.
  • the anti-interference ability of the spread spectrum technology makes the spread spectrum communication channel resistant to the interference of the 0FDM communication channel signal.
  • the signaling signal and the communication data are transmitted in parallel. 2. There is no need to define "coexistence negotiation dedicated time slice".
  • the spread spectrum communication channel of signaling can work in parallel with the OFDM communication channel of normal communication data, so that the signaling signal occupies scarce wireless communication resources of the base station system. ;
  • the spread spectrum signal is submerged in the noise, which is difficult to monitor and intercept, making it more difficult to perform direction finding, so that the system signaling channel naturally has good security features;
  • FIG. 1 is a schematic structural diagram of an embodiment of an OFDM and a direct sequence spread spectrum transmitter according to the present invention
  • FIG. 2 is a schematic structural diagram of an embodiment of an OFDM and a direct sequence spread spectrum receiver according to the present invention
  • FIG. 3 is a schematic diagram of a broadband-containing information signal received by a receiving end of a baseband processing portion of a spread spectrum communication channel in the OFDM and direct sequence spread spectrum receiver according to the present invention
  • FIG. 4 is a schematic diagram of signal power spectrum after performing spread spectrum demodulation processing in the OFDM and direct sequence spread spectrum receiver according to the present invention
  • 5 is a signal power spectrum processed by a narrowband filter in the OFDM and direct sequence spread spectrum receiver of the present invention
  • FIG. 6 is a schematic structural diagram of an embodiment of an OFDM and frequency hopping spread spectrum transmitter according to the present invention.
  • FIG. 7 is a schematic structural diagram of an embodiment of an OFDM and frequency hopping spread spectrum receiver according to the present invention. Mode for carrying out the invention
  • the embodiments of the present invention provide a spread spectrum orthogonal frequency division multiplexing hybrid system and method.
  • the main technical features of the embodiments of the present invention are as follows: signaling (including coexistence negotiation signaling between adjacent base stations) has a low transmission rate.
  • signaling including coexistence negotiation signaling between adjacent base stations
  • the spread spectrum communication channel for processing the normal communication data is processed through the 0FDM communication channel due to the high transmission rate, and the spread spectrum communication channel and the 0FDM communication channel can overlap each other in the communication frequency band and work in parallel.
  • the spread spectrum orthogonal frequency division multiplexing hybrid system is composed of an 0FDM transmitter and a spread spectrum transmitter, and an 0FDM receiver and a spread spectrum receiver.
  • the 0FDM transmitter includes: 0FDM communication channel, upconverter, power amplifier unit and transmit antenna.
  • Spread spectrum transmitter Includes: Direct Sequence Spread Spectrum Communication Channel, Upconverter, Power Amplifier Unit, and Transmit Antenna.
  • the above OFDM transmitter and spread spectrum transmitter can be physically integrated.
  • FIG. 1 A schematic diagram of the structure of an OFDM transmitter and a spread spectrum transmitter integrated in the present invention is shown in FIG. These include - direct sequence spread spectrum communication channels, OFDM communication channels, upconverters, power amplifier units, and transmit antennas.
  • the direct sequence spread spectrum communication channel unit performs channel coding on the received signaling (including coexistence negotiation signaling between adjacent base stations), performs modulation by using a spreading code sequence, and performs digital modulation processing, and then performs signaling.
  • the signal is sent to the up-converter and the power amplifier unit; wherein, the OFDM communication channel unit: digitally modulates the received communication data, performs serial-to-parallel conversion processing or serial-to-parallel conversion, digital modulation processing, and converts into a data sequence, and performs inverse fast Fourier transform.
  • the up-converter and the power amplifier unit Transmitting the processed signal sent by the received direct sequence spread spectrum communication channel unit and the communication data sent by the OFDM communication channel unit to the transmitting antenna; wherein, the transmitting signal is sent to the transmitting antenna; Antenna: Pass the received signal from the upconverter and power amplifier unit through the wireless Road sent out.
  • the baseband processing portion of the direct sequence spread spectrum communication channel is composed of a channel coding unit, a spread spectrum modulation unit, a spread code generator, and a digital modulator.
  • the baseband processing portion of the 0FDM communication channel is composed of a channel coding unit, a digital modulation unit, a serial-to-parallel transform, an IFFT unit, a parallel-to-serial conversion, and an insertion cyclic prefix unit.
  • the processing process of the baseband processing part of the direct sequence spread spectrum communication channel is mainly as follows: ⁇ Direct sequence spread spectrum mode is adopted.
  • the spread of the spectrum is obtained by directly modulating a high code rate spreading code sequence.
  • the binary information of the signaling input on the spread spectrum communication channel such as the binary information of the coexistence negotiation signaling, is modulated by the spreading code sequence generated by the spreading code generator after channel coding to broaden the spectrum of the signaling signal
  • the digital modulator After being modulated by the digital modulator, it is sent to the upconverter and the power amplifier unit for processing.
  • the above-mentioned spreading code sequence uses a pseudo-random code (PN code) sequence, which has better autocorrelation and cross-correlation properties. Finally, it is sent out through the transmitting antenna.
  • PN code pseudo-random code
  • the transmitting antennas are simultaneously transmitted on the overlapping frequency bands.
  • the OFDM receiver includes: a receive antenna, a low-turn amplifier and a downconverter unit, and an OFDM communication channel unit.
  • the spread spectrum receiver includes: a receiving antenna, a low-turn amplifier and a down-converter unit, and a direct-sequence spread spectrum communication channel unit. The above OFDM receiver and spread spectrum receiver can be physically integrated.
  • FIG. 2 A schematic diagram of the structure of an OFDM receiver and a spread spectrum receiver integrated in the present invention is shown in FIG. 2.
  • These include: receive antenna, low-turn amplifier and downconverter units, direct-sequence spread spectrum communication channel elements, and OFDM communication channel units.
  • the receiving antenna sends the signal received from the wireless channel to the low-voltage amplifier and the down-converter unit.
  • the low-turn amplifier and the down-converter unit the signal sent by the receiving antenna is amplified and down-converted, and then sent to the direct-sequence spread spectrum communication channel unit and the OFDM communication channel unit.
  • the direct sequence spread spectrum communication channel unit digitally demodulates the signal sent by the low chirp amplifier and the down converter unit, performs spread spectrum demodulation through the spreading code sequence, and performs narrowband of the spread spectrum demodulated signal. After filtering and channel decoding processing, the signaling information carried in the signal sent by the low-frequency amplifier and the down-converter unit is obtained.
  • the 0FDM communication channel unit serially converts the signal sent by the low-turn amplifier and the down-converter unit, deletes the cyclic prefix processing, and performs fast Fourier transform on the signal to obtain a frequency domain signal, and digitally signals the frequency domain signal
  • serially converts the signal sent by the low-turn amplifier and the down-converter unit deletes the cyclic prefix processing, and performs fast Fourier transform on the signal to obtain a frequency domain signal
  • digitally signals the frequency domain signal After demodulation, parallel-serial conversion processing or parallel-serial conversion, digital demodulation processing, communication data information carried in the signals transmitted by the low-turn amplifier and the down-converter unit is obtained through channel decoding processing.
  • the channel estimation unit is configured to: estimate time and frequency domain characteristics of the wireless channel of the 0FDM and the spread spectrum receiver, and transmit the obtained channel estimation values in the time domain and the frequency domain to the 0FDM communication channel unit, and obtain the time domain. And/or channel estimation values in the frequency domain are passed to the spread spectrum communication channel unit.
  • the baseband processing portion of the spread spectrum communication channel is composed of a channel decoding unit, a spread spectrum demodulation unit, a spread code generator, a narrowband filter, and a digital demodulator.
  • the baseband processing portion of the OFDM communication channel is composed of a channel decoding unit, a digital demodulation unit, a parallel-to-serial conversion, an FFT unit, a delete cyclic prefix unit, and a serial-to-parallel transform group.
  • the signal received from the receiving antenna is subjected to low-frequency amplifier amplification and down-converter down-conversion processing, and then sent to the baseband processing portion of the spread spectrum communication channel and the baseband processing portion of the OFDM communication channel for further processing.
  • the processing process of the baseband processing part of the direct sequence spread spectrum communication channel is mainly: the broadband information signal containing the noise received by the receiving end of the baseband processing part of the direct sequence spread spectrum communication channel
  • the schematic is shown in Figure 3.
  • the power of the signaling signal is lower than the power of white noise, which is much lower than the power of the OFDM signal.
  • the broadband information signal containing the noise received by the receiving end is digitally demodulated first, and then subjected to spread spectrum demodulation processing by the same spreading code sequence generated by the local spreading code generator and the same, and the spread spectrum demodulation is performed.
  • the signal power spectrum of the processed signal is shown in Figure 4.
  • the noise and the OFDM communication channel signal contained in the broadband information signal are subjected to spread spectrum demodulation processing, the spectrum spreads and the power density does not change, and the signal carrying the coexistence negotiation signaling contained in the broadband information signal is subjected to spread spectrum demodulation processing. After that, the energy is accumulated by the spreading code bit, and the power density is increased.
  • the signal subjected to the spread spectrum demodulation process is processed by the narrowband filter and the channel decoding unit to recover the binary information of the coexistence negotiation signaling carried in the broadband information signal.
  • the signal power spectrum diagram after passing through the narrow-band filter is shown in FIG. 5. After the narrow-band filtering process, the accumulated and accumulated signal carrying the coexistence negotiation signaling can be obtained, and the external interference and noise contained in the broadband information signal are excluded. Communication impact with other users.
  • the channel estimation unit in the above OFDM and direct sequence spread spectrum receiver is used to estimate the time domain and frequency domain characteristics of the wireless channel to cancel the channel distortion generated when the signal is transmitted on the wireless channel.
  • the channel estimation unit takes the output of the OFDM demodulator FFT unit as an input, performs two-dimensional (time domain and frequency domain) channel estimation, and the channel corresponding estimated value can be a smart antenna beamformer, a space-time decoder, a diversity combining, and an equalization.
  • the multiplexer, the digital demodulation unit, and the channel decoding unit Used by the multiplexer, the digital demodulation unit, and the channel decoding unit; for the OFDM communication channel, a two-dimensional channel estimation value is required, and the two-dimensional channel estimation value can be degraded into a one-dimensional channel estimation value, which is used for the spread spectrum communication channel.
  • a GPS (Global Positioning System) receiver is used as a time synchronization reference signal for the 0FDM communication channel and the spread spectrum communication channel.
  • the direct sequence spread spectrum communication channel unit and the OFDM communication channel unit in the above OFDM transmitter and spread spectrum transmitter, OFDM receiver and spread spectrum receiver may overlap and work in parallel on the communication frequency band.
  • the sequence of spreading codes is the same.
  • the spreading code sequence includes a pseudo-random PN code sequence.
  • the spread spectrum communication channel unit and the OFDM communication channel unit of the OFDM transmitter and the spread spectrum transmitter in Embodiment 1 above may each correspond to an upconverter and a power amplifier unit and a transmission antenna.
  • the gP0FDM and direct sequence spread spectrum transmitters can include two upconverters and power amplifier units, and transmit antennas, but the two transmit antennas must operate in the same frequency band.
  • the spread spectrum communication channel unit and the OFDM communication channel unit of the OFDM receiver and the spread spectrum receiver in Embodiment 1 described above may each correspond to a reception antenna, a low-turn amplifier and a down-converter unit, and a channel estimation unit. That is, OFDM and direct sequence spread spectrum receivers can include two receive antennas, low-turn amplifiers, and down-converter units, but the two receive antennas must operate in the same frequency band.
  • the fast Fourier transform and the fast Fourier transform in the above Embodiment 1 can also be other orthogonal frequency division multiplexing processing.
  • the spread spectrum orthogonal frequency division multiplexing hybrid system is composed of an OFDM transmitter, a frequency hopping spread spectrum transmitter, an OFDM receiver, and a frequency hopping spread spectrum receiver.
  • the OFDM transmitter includes: an OFDM communication channel, an upconverter, a power amplifier unit, and a transmit antenna.
  • the frequency hopping spread spectrum transmitter includes: a frequency hopping spread spectrum communication channel, an upconverter, a power amplifier unit, and a transmitting antenna.
  • the OFDM transmitter and the frequency hopping spread spectrum transmitter described above can be physically integrated.
  • FIG. 6 A schematic diagram of an OFDM transmitter and a frequency hopping spread spectrum transmitter integrated in the present invention is shown in FIG. 6, and includes: a frequency hopping spread spectrum communication channel unit, an 0FDM communication channel unit, an up converter, and a power amplifier unit. Transmitting antenna.
  • the frequency hopping spread spectrum communication channel unit comprises: a channel coding unit, a digital modulator, a mixer, a spread code generator and a frequency synthesizer, and performs channel coding on the received signaling signal, and performs modulation by a digital modulator.
  • the 0FDM communication channel unit digitally modulates the received communication data, performs serial-to-parallel conversion processing or serial-to-parallel conversion, digital modulation processing, and converts into a data sequence, and converts the data sequence by inverse fast Fourier transform For the time domain sequence, insert a cyclic prefix into the time domain sequence, and then perform a parallel and serial conversion to send the time domain sequence to The up-converter and the power amplifier unit; wherein, the up-converter and the power amplifier unit: the signaling signal sent by the received frequency hopping spread spectrum communication channel unit and the communication data sent by the OFDM communication channel unit are subjected to up-conversion and power amplification After processing, the processed signal is sent to the transmitting antenna; wherein, the transmitting antenna:
  • the baseband processing part of the above-mentioned frequency hopping spread spectrum communication channel adopts a frequency hopping spread spectrum method, and is composed of a channel coding unit, a mixer, a frequency synthesizer, a spread code generator and a digital modulator.
  • the processing of the baseband processing portion of the frequency hopping spread spectrum communication channel is mainly: binary information of signaling input in the frequency hopping spread spectrum communication channel, such as binary of coexistence negotiation signaling.
  • the information is channel-coded and then modulated by a digital modulator.
  • the mixer outputs the frequency of the signal and the output frequency of the frequency synthesizer controlled by the spread code sequence generated by the spread code generator by the mixer to broaden the spectrum of the signal, and then mixes the processed signal.
  • the signal is sent to the upconverter and the power amplifier unit for processing, and finally transmitted simultaneously through the transmitting antenna on the overlapping frequency bands.
  • the spreading code sequence can use a pseudo-random code (PN code) sequence, which has better autocorrelation and cross-correlation properties.
  • PN code pseudo-random code
  • the structure and processing of the baseband processing portion of the OFDM communication channel are the same as those of the above OFDM and direct sequence spread spectrum transmitter.
  • the OFDM receiver includes: a receive antenna, a low-turn amplifier and a downconverter unit, and an OFDM communication channel unit.
  • the frequency hopping spread spectrum receiver includes: a receiving antenna, a low ⁇ amplifier and a down converter unit, and a frequency hopping direct sequence spread spectrum communication channel unit.
  • the above 0FDM receiver and frequency hopping spread spectrum receiver can be physically integrated.
  • FIG. 7 A schematic diagram of an OFDM receiver and a frequency hopping spread spectrum receiver integrated with the present invention is shown in FIG. 7, and includes: a receiving antenna, a low ⁇ amplifier and a down converter unit, a frequency hopping spread spectrum communication channel unit, and 0FDM communication channel unit.
  • the receiving antenna sends the signal received from the wireless channel to the low-voltage amplifier and the down-converter unit; wherein, the low-turn amplifier and the down-converter unit: after the signal sent by the receiving antenna is amplified and down-converted Sending to the frequency hopping spread spectrum communication channel unit and the 0FDM communication channel unit;
  • the frequency hopping spread spectrum communication channel unit comprises: a mixer, a spreading code generator, a frequency synthesizer, The mixer mixes the signal sent by the low-turn amplifier and the down-converter unit with the output frequency of the frequency synthesizer controlled by the spread code sequence generated by the local spread code generator, and performs the mixed-processed signal.
  • the decoding process obtains communication data information carried in the signals transmitted by the low-voltage amplifier and the down-converter unit.
  • the channel estimation unit is configured to: estimate time and frequency domain characteristics of the radio channel of the OFDM and the spread spectrum receiver, and transmit the obtained channel estimation values in the time domain and the frequency domain to the OFDM communication channel unit, and obtain the time domain. And/or channel estimation values in the frequency domain are passed to the spread spectrum communication channel unit.
  • the baseband processing portion of the frequency hopping spread spectrum communication channel is composed of a channel decoding unit, a frequency synthesizer, a spread code generator, a mixer, and a digital demodulator.
  • the processing process of the baseband processing part of the frequency hopping spread spectrum communication channel is mainly as follows: first, the broadband information signal containing the noise received by the receiving end and the local expansion are performed by the mixer. The output frequency of the frequency synthesizer controlled by the spreading code sequence generated by the frequency code generator is mixed, and then the mixed-processed signal is digitally demodulated and channel decoded to recover the coexistence negotiation carried in the broadband information signal. Binary information for signaling.
  • the structure and processing procedure of the baseband processing section and the channel estimating section of the OFDM communication channel are the same as those of the above OFDM and direct sequence spread spectrum receiver. .
  • the above OFDM receiver and the frequency hopping spread spectrum receiver use a GPS receiver as a time synchronization reference signal of the OFDM communication channel unit and the frequency hopping spread spectrum communication channel unit.
  • the direct sequence spread spectrum communication channel unit and the 0FDM communication channel unit in the above 0FDM transmitter and frequency hopping spread spectrum transmitter, 0FDM receiver and frequency hopping spread spectrum receiver can overlap and work in parallel on the communication frequency band.
  • the above-mentioned 0FDM transmitter and the direct-sequence spread spectrum communication channel unit of the frequency hopping spread spectrum transmitter perform a spread spectrum coded spread code sequence and the direct sequence spread spectrum communication channel unit of the above-mentioned 0FDM receiver and the frequency hopping spread spectrum receiver are expanded.
  • the frequency demodulated spreading code sequence is the same.
  • the spreading code sequence includes a pseudo-random PN code sequence.
  • the spread spectrum communication channel unit and the 0FDM communication channel unit of the 0FDM transmitter and the frequency hopping spread spectrum transmitter in the second embodiment described above may each correspond to an upconverter and a power amplifier unit and a transmitting antenna. That is, the 0FDM and the direct sequence spread spectrum transmitter can include two upconverters and power amplifier units and transmit antennas, but the two transmit antennas must operate in the same frequency band.
  • the channel elements can each correspond to a receive antenna, a low-turn amplifier, and a down-converter unit.
  • Two receive antennas, low-turn amplifiers, and downconverter units can be included in the SP0FDM and direct-sequence spread spectrum receivers, but the two receive antennas must operate in the same frequency band.
  • the fast Fourier transform and the fast Fourier transform in the above embodiment 2 can also be other orthogonal frequency division multiplexing processing.
  • the transmitting end performs digital modulation and spreading processing on the first signal to obtain a spread spectrum communication signal, and performs a fast Fourier transform process on the second signal to obtain an OFDM communication signal, and the spread spectrum communication signal and the OFDM communication signal are on overlapping frequency bands. Send out at the same time;
  • the receiving end receives the signal sent by the transmitting end, performs digital demodulation and spread spectrum demodulation processing on the signal to obtain the first signal, and performs fast Fourier transform processing on the signal to obtain the second signal.
  • the main processing procedure of the sending end is:
  • the transmitting end performs channel coding on the received signaling signal, performs modulation by the spreading code sequence, and performs digital modulation processing; the transmitting end performs digital modulation, serial-to-parallel conversion processing, serial-to-parallel conversion, and digital modulation on the received communication data. After processing, it is converted into a data sequence, and the data sequence is converted into a time domain sequence by an inverse fast Fourier transform, and a cyclic prefix is inserted into the time domain sequence and then subjected to parallel-to-serial conversion processing.
  • the transmitting end performs the up-conversion and power amplification processing on the processed signaling signal and the communication data, and then sends the processed signal to the transmitting antenna, and the transmitting antenna transmits the received signal through the wireless channel in an overlapping manner. Send out at the same time in the frequency band.
  • the main processing procedure of the receiving end is: the receiving end performs digital demodulation on the signal after performing amplification and down-conversion processing on the signal received by the receiving antenna from the wireless channel.
  • the receiving end receives the received signal from the wireless channel through the receiving antenna.
  • the signal is amplified and down-converted, the signal is serial-to-parallel converted and the cyclic prefix processing is deleted.
  • the signal is fast Fourier transformed, the frequency domain signal is obtained, and the frequency domain signal is digitally demodulated and serial-converted.
  • the communication data is obtained through channel decoding processing.
  • the main processing procedure of the sending end is:
  • the transmitting end performs channel coding on the received signaling signal, performs modulation processing by the digital modulator, and then synthesizes the signal output by the digital modulator and the frequency controlled by the spreading code sequence generated by the spreading code generator through the mixer.
  • the output frequency of the device is mixed; the transmitting end performs digital modulation, serial-to-parallel conversion processing, serial-to-parallel conversion, digital modulation processing, and then converts the data into a data sequence, and converts the data sequence into a data sequence by inverse fast Fourier transform.
  • the time domain sequence is inserted into the time domain sequence and then subjected to parallel and serial conversion processing.
  • the transmitting end performs the up-conversion and power amplification processing on the processed signaling signal and the communication data, and then sends the processed signal to the transmitting antenna, and the transmitting antenna transmits the received signal through the wireless channel in an overlapping manner. Send out at the same time in the frequency band.
  • the main processing procedure of the receiving end is:
  • the receiving end amplifies and down-converts the signal received by the receiving antenna from the wireless channel, and then mixes the signal with the output frequency of the frequency synthesizer controlled by the spreading code sequence generated by the local spreading code generator. And performing digital demodulation and channel decoding on the mixed processed signal to obtain the signaling signal;
  • the receiving end performs amplification and down-conversion processing on the signal received by the receiving antenna from the wireless channel, and then performs fast Fourier transform on the signal to obtain a frequency domain signal, and performs digital demodulation and parallel conversion processing on the frequency domain signal or After the parallel-serial conversion and digital demodulation processing, the communication data is obtained through channel decoding processing.

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Description

扩频正交频分复用混合系统和方法
技术领域
本发明涉及通讯领域， 尤其涉及一种扩频 OFDM (orthogonal frequency division multiplexing, 正交频分复用） 混合系统和方法。
发明背景
扩频通信 （SS: Spread Spectrum)是指将原始信息频带展宽， 使该原始信息在更 宽的频带内传输， 而在接收端通过相关接收技术来恢复原始信息频带的一种技术。扩频 通信的方法主要包括： 直接序列扩频（DS: Direct Sequence Spread Spectrum, 简称 直扩） 、 跳频扩频 (FH: Frequency Hopping) 、 跳时 (TH: Time Hopping) 、 线性调 频 （Chirp) 。
上述直接序列扩频就是直接用高速率的伪随机扩频码 PN序列在发送端扩展原始信 息信号的频谱， 然后， 将扩频信号发送给接收端。在接收端用相同的扩频码 PN序列对接 收到的上述扩频信号进行解扩， 把展宽的扩频信号还原成原始信息信号。接收机解扩实 际上是对干扰信号进行频谱展宽， 把干扰信号变成功率谱密度很低而频谱很宽的信号， 经窄带滤波器滤除后， 使落到带内的干扰信号能量很小， 而有用的数字信号被压缩还原 成窄带信号，顺利通过滤波器。因此，上述直接序列扩频的系统具有很强的抗干扰能力， 该系统中的一种扩频调制的方法是把信息序列和伪随机序列直接作模 2相加或相乘， 产 生一个速率与伪随机序列码速相同的扩频序列。
扩频通信具有如下优点： （1 )频谱密度低， 对其它系统的电磁干扰小； （2 )抗干 扰性强， 误码率低； (3) 具有信息保密性； （4)可以实现码分多址。
例如， .一个扩频系统的可用带宽扩展因子为 1000， 则处理增益为 101gl000=30dB， 要求误码率小于 1(Τ的信息数据 BPSK (Binary Phase Shift Keying, 二相相移键控） ， 解调的最小的比特输出信噪比小于 10. 5dB， 系统损耗 Ls=3dB, 则干扰容限 =30 - ( 10. 5 + 3) =16. 5dB„ 该系统能在干扰输入功率电平比扩频信号功率电平高 16. 5dB的范围内 正常工作，也就是该系统能够在接收输入信噪比大于或等于 -16. 5dB的环境下正常工作。 该干扰容限是用未编码的 DS扩频系统获得的， 故还可利用信息序列编码增加此干扰容 限。
0FDM的基本原理是将编码后的串行数据转换为并行数据， 然后， 釆用频率上等间隔 的 N个载波分别对上述并行数据进行调制，再将调制后获得的 N个子载波的信号相加后同 时发送，这样每个子载波符号的频谱只占可用信道带宽的一小部分。通过选择载波间隔， 使这些子载波在整个符号周期上保持频谱的正交性，各子载波上的信号在频谱上相互重 叠， 接收端利用载波之间的正交性就可以无失真的恢复出发送信息。 OFDM可通过 IFFT ( Inversed Fast Fourier Transform, 快速傅立叶逆变换变换） /FFT (Fast Fourier Transform, 快速傅立叶变换）对来实现。
OFDM通信具有如下优点： （1 )频谱利用率髙， 理论上可以达到 Shannon信息论的极 限； （2) 能有效地克服 ISI ( Intersymbol Interference, 符号间干扰） ； （3 ) 能有 效地抵抗信道衰落。 OFDM技术把频率选择性衰落信道划为多个并行的相关的平坦衰落信 道， 因此， 采用简单的信道均衡技术就能满足系统性能要求， 不需要釆用复杂的自适应 均衡技术； （4)抗噪声干扰， OFDM对信道噪声干扰的克服是通过子信道分配来实现的。 (5 )适合高速数据传输。
OFDM自适应调制机制使不同的子载波可以按照信道情况和噪音背景的不同使用不同 的调制方式。 当信道条件好的时候， 采用效率高的调制方式。 当信道条件差的时候， 采 用抗干扰能力强的调制方式。 另外， OFDM加载算法的釆用， 使系统可以把更多的数据集 中放在条件好的信道上以高速率进行传送。 因此， OFDM技术非常适合高速数据传输。
相比之下， CDMA ( code division multiple access, 码分多址接入） 的 RF频宽要求 比数据速率大很多， 以保证有足够的处理增益对抗干扰。 对于 11GHz以下频段的宽带无 线通信， 用 CDMA传送高速数据显然较不现实， 例如， 为了使数据速率达到 70 Mbps, RF 频宽需要超过 200MHz， 以维持足够的处理增益和 NL0S (Non Line- of- Sight, 非视距传 播） 通信性能。
目前宽带无线接入技术正在蓬勃发展，利用无线资源开展宽带城域接入的技术具有 很强的生命力和市场空间。与此同时， 无线的频谱资源非常宝贵， 特别是在没有很好规 划频谱资源的区域或没有许可的频段， 往往会在相同的信道上有多个基站运行， 导致多 个基站的所属系统之间相互干扰。 为了协调同频段下各基站之间的共存， 尤其是免许可 频段的基站共存，相邻基站之间需要相互进行协商以解决同频段或邻频段下工作共存问 题。
现有技术中一种解决基站之间共存问题的方法为：在原有基站系统的帧格式的下行 子帧中定义一个 "共存协商专用时间片"，相邻基站之间利用该 "共存协商专用时间片" 进行协商以解决同频段或邻频段下工作共存问题。
上述解决基站之间共存问题的方法的缺点为- 1、 上述 "共存协商专用时间片"必须全网统一、 跨网统一或跨地区统一， 这种强 制性要求通常必须由政府部门以政策形式推行， 难度较大；
2、 在原有基站系统的帧格式中划分 "共存协商专用时间片" ， 在一定程度上占用 了基站系统的稀缺的无线通信资源， 在该时间片上基站系统不能做正常的业务通信， 该 问题在协商信令流量大时尤为突出。 发明内容
本发明实施例的目的是提供一种扩频正交频分复用混合系统和方法， 从而可以使信 令信号和通信数据并行传输， 避免了信令信号占用基站系统的稀缺的无线通信资源。
本发明实施例的目的是通过以下技术方案实现的：
一种扩频正交频分复用混合系统， 包括： 正交频分复用 OFDM发射机和扩频发射机， 正交频分复用 OFDM发射机： 将第一信号进行正交频分复用处理获得 OFDM通信信号， 通过发射天线在和扩频发 机共同占用的频段上将所述 OFDM通信信号进行发送；
扩频发射机： 将第二信号进行扩频调制处理获得扩频通信信号， 通过发射天线在和 OFDM发射机共同占用的频段上将所述扩频通信信号进行发送。
一种扩频正交频分复用混合方法， 包括：
将第一信号进行正交频分复用处理获得 OFDM通信信号， 将第二信号进行扩频调制 处理获得扩频通信信号， 通过发射天线将所述扩频通信信号、 OFDM通信信号在共同占 用的频段上同时进行发送。
由上述本发明实施例提供的技术方案可以看出， 本发明实施例通过将 0FDM和扩频通 信技术相结合， 将信令信号通过扩频通信通道进行处理， 将正常的通信数据通过 0FDM通 信通道进行处理。 和现有技术相比， 具有如下优点：
1、 由于扩频通信通道的信号频谱带宽远大于所传的信令信息带宽， 所以扩频通信 通道的扩频信号的功率谱密度可以远远小于 0FDM通信通道的信号功率谱密度。 在发送 端， 扩频通信通道可以以远低于 0FDM通信通道的功率发送信令信号， 从而使扩频通信通 道信号不至于干扰 0FDM通信通道信号； 在接收端， 扩频通信通道甚至可以在信号完全淹 没在噪声的情况下工作， 即当接收到的扩频通信通道的扩频信号的功率谱密度低于信道 噪声（包括接收机的前端热噪声和信道中的加性噪声）功率谱密度时， 扩频通信通道接 收机仍可正常工作，扩频技术的抗干扰能力使得扩频通信通道可以抵抗 0FDM通信通道信 号的干扰。 实现了信令信号和通信数据并行传输。 2、 无须定义 "共存协商专用时间片" ， 信令的扩频通信通道可以和正常通信数据 的 OFDM通信通道在同频段上并行工作，所以避免了信令信号占用基站系统的稀缺的无线 通信资源；
3、 扩频信号淹没在噪声中， 很难进行监视、 截获， 更难进行测向， 使得系统信令 信道天然地具有很好的保密特性；
4、 由于避免了全网统一、 跨网统一或跨地区统一的 "共存协商专用时间片" ， 极 大地降低了政府部门的政策干预程度。 附图简要说明
图 1为本发明所述 OFDM和直序扩频发射机的实施例的结构示意图；
图 2为本发明所述 OFDM和直序扩频接收机的实施例的结构示意图；
图 3为在本发明所述 OFDM和直序扩频接收机中 , 扩频通信通道的基带处理部分的接 收端收到的含有噪声的宽带信息信号示意图；
图 4为在本发明所述 OFDM和直序扩频接收机中， 进行了扩频解调处理后的信号功率 谱示意图；
图 5为在本发明所述 OFDM和直序扩频接收机中， 经过窄带滤波器处理后的信号功率 谱；
图 6为本发明所述 OFDM和跳频扩频发射机的实施例的结构示意图；
图 7为本发明所述 OFDM和跳频扩频接收机的实施例的结构示意图。 实施本发明的方式
本发明实施例提供了一种扩频正交频分复用混合系统和方法， 本发明实施例的主 要技术特点为： 信令 （包括相邻基站间共存协商信令）信号由于传输速率较低， 通过扩 频通信通道进行处理，正常的通信数据由于传输速率较高，通过 0FDM通信通道进行处理， 扩频通信通道和 0FDM通信通道在通信频段可以互相重叠， 并行工作。
下面结合附图来详细描述本发明所述系统的两个实施例， 下面分别介绍该两个实 施例。
实施例 1中， 扩频正交频分复用混合系统由 0FDM发射机和扩频发射机、 以及 0FDM接 收机和扩频接收机组成。
0FDM发射机包括： 0FDM通信通道、 上变频器、 功放单元和发射天线。 扩频发射机 包括： 直序扩频通信通道、 上变频器、 功放单元和发射天线。 上述 OFDM发射机和扩频发 射机可以在物理上集成在一起。
本发明所述一种 OFDM发射机和扩频发射机集成在一起的结构示意图如图 1所示。包 括- 直序扩频通信通道、 OFDM通信通道、 上变频器、 功放单元和发射天线。
其中， 直序扩频通信信道单元： 将接收到的信令（包括相邻基站间共存协商信令) 信号进行信道编码， 通过扩频码序列进行调制， 再进行数字调制处理后， 将信令信号发 送给上变频器和功放单元； 其中， OFDM通信信道单元： 将接收到的通信数据进行数字调制、 串并转换处理或 串并转换、数字调制处理后转化为数据序列， 通过快速傅立叶逆变换将该数据序列转化 为时域序列， 在该时域序列中插入循环前缀， 再经过并串转换后， 将该时域序列发送给 上变频器和功放单元； 其中， 上变频器和功放单元： 将接收到的直序扩频通信信道单元发送过来的信令 信号和 OFDM通信信道单元发送过来的通信数据， 进行上变频和功率放大处理后， 将处理 后的信号发送给发射天线； 其中， 发射天线： 将接收到的上变频器和功放单元发送过来的信号通过无线信道 发送出去。 直序扩频通信通道的基带处理部分由信道编码单元、 扩频调制单元、 扩频码产生 器和数字调制器组成。 ·
0FDM通信通道的基带处理部分由信道编码单元、 数字调制单元、 串并变换、 IFFT 单元、 并串变换和插入循环前缀单元组成。
在上述 0FDM和直序扩频发射机中， 直序扩频通信通道的基带处理部分的处理过程 主要为： 釆用直序扩频方式。在该方式中频谱的扩展是直接由高码率的扩频码序列进行 调制而得到的。在扩频通信通道上输入的信令的二进制信息， 比如共存协商信令的二进 制信息， 经信道编码后， 由扩频码发生器产生的扩频码序列进行调制， 以展宽信令信号 的频谱， 再经过数字调制器进行调制处理后， 送往上变频器和功放单元进行处理。上述 扩频码序列釆用伪随机码 （PN码） 序列， 该序列有较优良的自相关和互相关特性。 最 后通过发射天线发送出去。
在上述 0FDM和直序扩频发射机中， 0FDM通信通道的基带处理部分的处理过程主要 为： 在 0FDM通信通道上输入的正常通信数据的二进制信息经信道编码后， 首先进行数字 调制、 串并转换 （或先进行串并转换， 再数字调制） ， 变为 N路并行传输的数据序列 { (/c)}， = 0，1，〜N— 1 ( N为子载波个数） 。 IFFT单元将该数据序列转化为时域序 列 0)}， W = 0，1，—N- 1。 随后在该时域序列中插入 CP (请提供英文， 循环前缀） ， 再经过并串转换后， 将该时域序列送往上变频器和功放单元进行处理。最后通过发射天 线在重叠的频段上同时发送出去。
OFDM接收机包括： 接收天线、 低躁放大器和下变频器单元和 OFDM通信信道单元。 扩频接收机包括： 接收天线、低躁放大器和下变频器单元和直序扩频通信信道单元。上 述 OFDM接收机和扩频接收机可以在物理上集成在一起。
本发明所述一种 OFDM接收机和扩频接收机集成在一起的结构示意图如图 2所示。包 括： 接收天线、 低躁放大器和下变频器单元、 直序扩频通信信道单元和 OFDM通信信道单 元。 其中， 接收天线： 将从无线信道上接收到的信号发送给低躁放大器和下变频器单 元。 其中， 低躁放大器和下变频器单元： 将接收天线发送过来的信号进行放大和下变 频处理后， 发送给直序扩频通信信道单元和 OFDM通信信道单元。
其中， 直序扩频通信信道单元： 将低躁放大器和下变频器单元发送过来的信号进 行数字解调， 通过扩频码序列进行扩频解调， 再将扩频解调后的信号进行窄带滤波、 信 道解码处理后， 获得所述低躁放大器和下变频器单元发送过来的信号中携带的信令信 息。 其中， 0FDM通信信道单元： 将低躁放大器和下变频器单元发送过来的信号进行串 并转换、删除循环前缀处理后， 对信号进行快速傅立叶变换后得到频域信号， 对该频域 信号进行数字解调、 并串转换处理或并串转换、 数字解调处理后， 再通过信道解码处理 获得所述低躁放大器和下变频器单元发送过来的信号中携带的通信数据信息。
其中， 信道估计单元： 用于估计 0FDM和扩频接收机的无线信道的时域和频域特性， 将获得的时域和频域的信道估计值传递给 0FDM通信通道单元， 将获得的时域和 /或频域 的信道估计值传递给扩频通信信道单元。 '
扩频通信通道的基带处理部分由信道解码单元、 扩频解调单元、 扩频码产生器、 窄带滤波器和数字解调器组成。 OFDM通信通道的基带处理部分由信道解码单元、 数字解调单元、 并串变换、 FFT单 元、 删除循环前缀单元和串并变换组^
从接收天线接收到的信号经低躁放大器放大和下变频器下变频处理后， 送往扩频 通信通道的基带处理部分和 OFDM通信通道的基带处理部分做进一步处理。
在上述 OFDM和直序扩频接收机中， 直序扩频通信通道的基带处理部分的处理过程 主要为：直序扩频通信通道的基带处理部分的接收端收到的含有噪声的宽带信息信号示 意图如图 3所示。 从图 3可以看出， 信令信号的功率低于白噪声的功率， 远远低于 OFDM信 号的功率。上述接收端收到的含有噪声的宽带信息信号先经过数字解调， 然后通过本地 扩频码产生器产生的与发送端相同的扩频码序列进行扩频解调处理，进行了扩频解调处 理后的信号功率谱示意图如图 4所示。 上述宽带信息信号中含有的噪声和 OFDM通信通道 信号经过扩频解调处理后， 频谱扩展， 功率密度不变， 而宽带信息信号中含有的携带共 存协商信令的信号， 经过扩频解调处理后， 其能量按扩频码位积累， 功率密度增大。
上述进行了扩频解调处理后的信号再经过窄带滤波器、 信道解码单元进行处理，， 恢复出宽带信息信号中携带的共存协商信令的二进制信息。经过窄带滤波器后的信号功 率谱示意图如图 5所示， 经过窄带滤波处理后可得到被积累后而突出的携带共存协商信 令的信号， 而排除上述宽带信息信号中含有的外部干扰、 噪音和其它用户的通信影响。
在上述 OFDM和直序扩频接收机中， OFDM通信通道的基带处理部分的处理过程主要 为： 在接收端， 从接收天线接收到的信号经低躁放大器放大和下变频器下变频处理后， 经过删除循环前缀和串并转换后， 信号表示为 " = G，1，〜N - 1， 再对信号进行 FFT操作后得到频域信号 { } , = G， J - 1。 然后， 对该频域信号做数字解调和并 串转换（或先进行并串转换、 再做数字解调） ， 最后进行信道解码处理后得到正常通信 数据的二进制信息。
上述 OFDM和直序扩频接收机中的信道估计单元用于估计无线信道的时域和频域 特性， 以抵消信号在无线信道上传输时所产生的信道畸变。 信道估计单元以 OFDM解调 器 FFT单元的输出作为输入， 进行二维 （时域和频域） 的信道估计， 信道相应估计值可 为智能天线波束成形器、 空时解码器、 分集合并、 均衡器、 数字解调单元和信道解码单 元所使用； 对于 OFDM通信通道， 需要使用二维信道估计值， 而二维信道估计值可以退 化为一维信道估计值， 为扩频通信通道所使用。
在上述 0FDM和直序扩频接收机中釆用 GPS (Global Positioning System, 全球定 位系统）接收机作为 0FDM通信通道和扩频通信通道的时间同步参考信号。 上述 OFDM发射机和扩频发射机、 OFDM接收机和扩频接收机中的直序扩频通信信道 单元和 OFDM通信信道单元在通信频段上可以重叠、 并行工作。
上述 OFDM发射机和扩频发射机的直序扩频通信信道单元进行扩频调制的扩频码序 列，和上述 OFDM接收机和扩频接收机的直序扩频通信信道单元进行扩频解调的扩频码序 列相同。 所述的扩频码序列包括伪随机 PN码序列。
上述实施例 1中的 OFDM发射机和扩频发射机的扩频通信信道单元和 OFDM通信信道 单元可以分别都和一个上变频器和功放单元、发射天线相对应。 gP0FDM和直序扩频发射 机中可以包括两个上变频器和功放单元、发射天线， 但两个发射天线必须工作在相同的 频段。
上述实施例 1中的 OFDM接收机和扩频接收机的扩频通信信道单元和 OFDM通信信道 单元可以分别都和一个接收天线、 低躁放大器和下变频器单元、 信道估计单元相对应。 即 OFDM和直序扩频接收机中可以包括两个接收天线、低躁放大器和下变频器单元， 但两 个接收天线必须工作在相同的频段。
上述实施例 1中的快速傅立叶变换和快速傅立叶逆变换还可以为其它正交频分复 用处理。
实施例 2中， 扩频正交频分复用混合系统由 OFDM发射机和跳频扩频发射机、 OFDM接 收机和跳频扩频接收机组成。
OFDM发射机包括： OFDM通信通道、 上变频器、 功放单元和发射天线。 跳频扩频发 射机包括： 跳频扩频通信通道、 上变频器、 功放单元和发射天线。 上述 OFDM发射机和跳 频扩频发射机可以在物理上集成在一起。
本发明所述一种 0FDM发射机和跳频扩频发射机集成在一起的结构示意图如图 6所 示， 包括： 跳频扩频通信信道单元、 0FDM通信信道单元、 上变频器和功放单元和发射天 线。
其中， 跳频扩频通信信道单元： 包括信道编码单元、 数字调制器、 混频器、 扩频 码发生器和频率合成器， 将接收到的信令信号进行信道编码， 经过数字调制器进行调制 处理，再通过混频器将数字调制器输出的信号和由扩频码发生器产生的扩频码序列控制 的频率合成器的输出频率进行混频， 将混频处理后的信号发送给上变频器和功放单元； 其中， 0FDM通信信道单元： 将接收到的通信数据进行数字调制、 串并转换处理或 串并转换、数字调制处理后转化为数据序列， 通过快速傅立叶逆变换将该数据序列转化 为时域序列， 在该时域序列中插入循环前缀， 再经过并串转换后， 将该时域序列发送给 上变频器和功放单元； 其中， 上变频器和功放单元： 将接收到的跳频扩频通信信道单元发送过来的信令 信号和 OFDM通信信道单元发送过来的通信数据， 进行上变频和功率放大处理后， 将处理 后的信号发送给发射天线； 其中， 发射天线： 将接收到的上变频器和功放单元发送过来的信号通过无线信道 发送出去。 上述跳频扩频通信通道的基带处理部分采用跳频扩频方式， 由信道编码单元、 混 频器、 频率合成器、 扩频码产生器和数字调制器组成。
在上述 OFDM和跳频扩频发射机中， 跳频扩频通信通道的基带处理部分的处理过程 主要为： 在跳频扩频通信通道输入的信令的二进制信息， 比如共存协商信令的二进制信 息， 经信道编码后， 再经过数字调制器进行调制处理。 然后， 通过混频器将数字调制器 输出的信号和由扩频码发生器产生的扩频码序列控制的频率合成器的输出频率进行混 频， 以展宽信号的频谱， 将混频处理后的信号发送给上变频器和功放单元进行处理， 最 后通过发射天线在重叠的频段上同时发送出去。 扩频码序列可釆用伪随机码（PN码）序 列， 该序列有较优良的自相关和互相关特性。
在上述 OFDM和跳频扩频发射机中， OFDM通信通道的基带处理部分的结构和处理过 程与上述 OFDM和直序扩频发射机的结构和处理过程相同。
OFDM接收机包括： 接收天线、 低躁放大器和下变频器单元和 OFDM通信信道单元。 跳频扩频接收机包括： 接收天线、低躁放大器和下变频器单元和跳频直序扩频通信信道 单元。 上述 0FDM接收机和跳频扩频接收机可以在物理上集成在一起。
本发明所述一种 0FDM接收机和跳频扩频接收机集成在一起的结构示意图如图 7所 示， 包括： 接收天线、 低躁放大器和下变频器单元、 跳频扩频通信信道单元和 0FDM通信 信道单元。 其中， 接收天线： 将从无线信道上接收到的信号发送给低躁放大器和下变频器单 元； 其中， 低躁放大器和下变频器单元： 将接收天线发送过来的信号进行放大和下变 频处理后， 发送给跳频扩频通信信道单元和 0FDM通信信道单元；
其中， 跳频扩频通信信道单元： 包括混频器、 扩频码发生器、 频率合成器， 通过 混频器将低躁放大器和下变频器单元发送过来的信号和由本地扩频码发生器产生的扩 频码序列控制的频率合成器的输出频率进行混频， 将混频处理后的信号进行数字解调、 信道解码， 获得所述低躁放大器和下变频器单元发送过来的信号中携带的信令信息； 其中， OFDM通信信道单元： 将低躁放大器和下变频器单元发送过来的信号进行串 并转换、 删除循环前缀处理后， 对信号进行快速傅立叶变换后得到频域信号， 对该频域 信号进行数字解调、 并串转换处理或并串转换、 数字解调处理后， 再通过信道解码处理 获得所述低躁放大器和下变频器单元发送过来的信号中携带的通信数据信息。
其中， 信道估计单元： 用于估计 OFDM和扩频接收机的无线信道的时域和频域特性， 将获得的时域和频域的信道估计值传递给 OFDM通信通道单元， 将获得的时域和 /或频域 的信道估计值传递给扩频通信信道单元。
跳频扩频通信通道的基带处理部分由信道解码单元、 频率合成器、 扩频码产生器、 混频器和数字解调器组成。
在上述 OFDM和跳频扩频接收机中， 跳频扩频通信通道的基带处理部分的处理过程 主要为： 先通过混频器将接收端收到的含有噪声的宽带信息信号， 和由本地扩频码发生 器产生的扩频码序列控制的频率合成器的输出频率进行混频， 再将混频处理后的信号进 行数字解调、信道解码，恢复出所述宽带信息信号中携带的共存协商信令的二进制信息。
在上述 OFDM和跳频扩频接收机中， OFDM通信通道的基带处理部分和信道估计单元 的结构和处理过程与上述 OFDM和直序扩频接收机相同。 .
上述 OFDM接收机和跳频扩频接收机中采用 GPS接收机作为 OFDM通信通道单元和跳 频扩频通信通道单元的时间同步参考信号。
上述 0FDM发射机和跳频扩频发射机、 0FDM接收机和跳频扩频接收机中的直序扩频 通信信道单元和 0FDM通信信道单元在通信频段上可以重叠、 并行工作。
上述 0FDM发射机和跳频扩频发射机的直序扩频通信信道单元进行扩频调制的扩频 码序列和上述 0FDM接收机和跳频扩频接收机的直序扩频通信信道单元进行扩频解调的 扩频码序列相同。 所述的扩频码序列包括伪随机 PN码序列。
上述实施例 2中的 0FDM发射机和跳频扩频发射机的扩频通信信道单元和 0FDM通信 信道单元可以分别都和一个上变频器和功放单元、 发射天线相对应。 即 0FDM和直序扩频 发射机中可以包括两个上变频器和功放单元、 发射天线， 但两个发射天线必须工作在相 同的频段。
上述实施例 2中的 0FDM接收机和直序扩频接收机的扩频通信信道单元和 0FDM通信 信道单元可以分别都和一个接收天线、 低躁放大器和下变频器单元相对应。 SP0FDM和直 序扩频接收机中可以包括两个接收天线、 低躁放大器和下变频器单元， 但两个接收天线 必须工作在相同的频段。
上述实施例 2中的快速傅立叶变换和快速傅立叶逆变换还可以为其它正交频分复 用处理。
本发明实施例提供的一种扩频正交频分复用混合方法的实施例的处理流程主要包 括：
发送端将第一信号进行数字调制和扩频处理获得扩频通信信号， 将第二信号进行 快速傅立叶逆变换处理获得 OFDM通信信号， 将所述扩频通信信号、 OFDM通信信号在重叠 的频段上同时发送出去；
接收端接收所述发送端发送的信号， 对该信号进行数字解调和扩频解调处理获得 所述第一信号； 对该信号进行快速傅立叶变换处理获得所述第二信号。
对应上述本发明所述系统的实施例 1， 所述发送端的主要处理过程为：
发送端将接收到的信令信号进行信道编码， 通过扩频码序列进行调制， 再进行数 字调制处理； 发送端将接收到的通信数据进行数字调制、 串并转换处理或串并转换、 数字调制 处理后转化为数据序列， 通过快速傅立叶逆变换将该数据序列转化为时域序列， 在该时 域序列中插入循环前缀再进行并串转换处理。 然后， 发送端将经过上述处理后的信令信号和通信数据， 进行上变频和功率放大 处理， 再将处理后的信号发送给发射天线， 该发射天线将接收到的信号通过无线信道在 重叠的频段上同时发送出去。 对应上述本发明所述系统的实施例 1， 所述接收端的主要处理过程为： 接收端将通过接收天线从无线信道上接收到的信号进行放大和下变频处理后， 对 该信号进行数字解调， 通过扩频码序列进行扩频解调， 再将扩频解调后的信号进行窄带 滤波、 信道解码处理后， 获得所述信令信号； 接收端将通过接收天线从无线信道上接收到的信号进行放大和下变频处理后， 对 该信号进行串并转换、 删除循环前缀处理后， 对该信号进行快速傅立叶变换后得到频域 信号， 对该频域信号进行数字解调、 并串转换处理或并串转换、 数字解调处理后， 再通 过信道解码处理获得所述通信数据。 对应上述本发明所述系统的实施例 2， 所述发送端的主要处理过程为：
发送端将接收到的信令信号进行信道编码， 经过数字调制器进行调制处理， 再通 过混频器将数字调制器输出的信号和由扩频码发生器产生的扩频码序列控制的频率合 成器的输出频率进行混频处理； 发送端将接收到的通信数据进行数字调制、 串并转换处理或串并转换、 数字调制 处理后转化为数据序列， 通过快速傅立叶逆变换将该数据序列转化为时域序列， 在该时 域序列中插入循环前缀再进行并串转换处理。 然后， 发送端将经过上述处理后的信令信号和通信数据， 进行上变频和功率放大 处理， 再将处理后的信号发送给发射天线， 该发射天线将接收到的信号通过无线信道在 重叠的频段上同时发送出去。 所述接收端的主要处理过程为：
接收端将通过接收天线从无线信道上接收到的信号进行放大和下变频处理后， 将 该信号和由本地扩频码发生器产生的扩频码序列控制的频率合成器的输出频率进行混 频， 将混频处理后的信号进行数字解调、 信道解码， 获得所述信令信号；
接收端将通过接收天线从无线信道上接收到的信号进行放大和下变频处理后， 对 该信号进行快速傅立叶变换后得到频域信号， 对该频域信号进行数字解调、 并串转换处 理或并串转换、 数字解调处理后， 再通过信道解码处理获得所述通信数据。
以上所述， 仅为本发明较佳的具体实施方式， 但本发明的保护范围并不局限于此， 任何熟悉本技术领域的技术人员在本发明揭露的技术范围内， 可轻易想到的变化或替 换， 都应涵盖在本发明的保护范围之内。 因此， 本发明的保护范围应该以权利要求的保 护范围为准。

Claims

权利要求
1、 一种扩频正交频分复用混合系统， 其特征在于， 包括： 正交频分复用 OFDM发射 机和扩频发射机，
正交频分复用 OFDM发射机： 将第一信号进行正交频分复用处理获得 OFDM通信信号， 通过发射天线在和扩频发射机共同占用的频段上将所述 OFDM通信信号进行发送；
扩频发射机： 将第二信号进行扩频调制处理获得扩频通信信号， 通过发射天线在 和 OFDM发射机共同占用的频段上将所述扩频通信信号进行发送。
2、 根据权利要求 1所述的扩频正交频分复用混合系统， 其特征在于， 所述扩频正 交频分复用混合系统还包括：
OFDM接收机： 通过接收天线同时接收所述扩频通信信号和 OFDM通信信号， 将接收 到的信号进行放大和下变频处理后， 获得所述 OFDM通信信号， 对该 OFDM通信信号进行正 交频分复用处理获得所述第一信号；
扩频接收机： 通过接收天线同时接收所述扩频通信信号和 OFDM通信信号， 将接收 到的信号进行放大和下变频处理后， 获得所述扩频通信信号， 对该扩频通信信号进行扩 频解调处理获得所述第二信号。
3、 根据权利要求 1所述的扩频正交频分复用混合系统， 其特征在于， 所述的 OFDM 发射机具体包括： OFDM通信信道单元、 上变频器和功放单元、 发射天线， 其中：
OFDM通信信道单元： 将接收到的通信数据进行数字调制、 串并转换处理或串并转 换、 数字调制处理后转化为数据序列， 通过正交频分复用处理将该数据序列转化为时域 序列， 在该时域序列中插入循环前缀再进行并串转换后， 将该时域序列发送给上变频器 和功放单元； 上变频器和功放单元： 将接收到的 0FDM通信信道单元发送过来的通信数据， 进行 上变频和功率放大处理， 将处理后的信号发送给发射天线； 发射天线： 将接收到的上变频器和功放单元发送过来的信号通过无线信道在和扩 频发射机共同占用的频段上进行发送。
4、 根据权利要求 3所述的扩频正交频分复用混合系统， 其特征在于， 所述的扩频 发射机具体包括： 直序扩频通信信道单元、 上变频器和功放单元、 发射天线， 其中- 直序扩频通信信道单元： 将接收到的信令信号进行信道编码」， 通过扩频码序列进 行调制， 再进行数字调制处理后， 将该信令信号发送给上变频器和功放单元； 上变频器和功放单元： 将接收到的直序扩频通信信道单元发送过来的信令信号进 行上变频和功率放大处理， 将处理后的信号发送给发射天线； 发射天线： 将接收到的上变频器和功放单元发送过来的信号， 通过无线信道在和
OFDM通信发射天线共同占用的频段上进行发送。
5、 根据权利要求 3所述的扩频正交频分复用混合系统， 其特征在于， 所述的扩频 发射机具体包括： 跳频扩频通信信道单元、 上变频器和功放单元、 发射天线， 其中： 跳频扩频通信信道单元： 将接收到的信令信号进行信道编码， 经过数字调制器进 行调制处理，再通过混频器将数字调制器输出的信号和由扩频码发生器产生的扩频码序 列控制的频率合成器的输出频率进行混频，将混频处理后的信号发送给上变频器和功放 单元； 上变频器和功放单元： 将接收到的跳频扩频通信信道单元发送过来的信令信号进 行上变频和功率放大处理后， 将处理后的信号发送给发射天线； 发射天线： 将接收到的上变频器和功放单元发送过来的信号， 通过无线信道在和 OFDM通信发射天线共同占用的频段进行发送。
6、 根据权利要求 4或 5所述的扩频正交频分复用混合系统， 其特征在于， 所述 OFDM 发射机中的上变频器和功放单元和扩频发射机中的上变频器和功放单元集成在一起；和 /或， 所述 OFDM发射机中的发射天线和扩频发射机中的发射天线集成在一起。
7、 根据权利要求 2所述的扩频正交频分复用混合系统， 其特征在于， 所述的 OFDM 接收机包括： 接收天线、 低躁放大器和下变频器单元、 OFDM通信信道单元， 其中： 接收天线： 将从无线信道上接收到的信号发送给低躁放大器和下变频器单元； 低躁放大器和下变频器单元： 将接收天线发送过来的信号进行放大和下变频处理 后获得 0FDM通信信号， 将该 0FDM通信信号发送给 0FDM通信信道单元；
0FDM通信信道单元： 将低躁放大器和下变频器单元发送过来的信号进行串并转换、 删除循环前缀处理后， 对信号进行正交频分复用处理后得到频域信号， 对该频域信号进 行数字解调、 并串转换处理或并串转换、 数字解调处理后， 再通过信道解码处理获得所 述低躁放大器和下变频器单元发送过来的信号中携带的通信数据信息。
8、 根据权利要求 7所述的扩频正交频分复用混合系统， 其特征在于， 所述的 0FDM 接收机还包括： 信道估计单元： 用于估计 OFDM接收机的无线信道的时域和频域特性， 将获得的时 域和频域的信道估计值传递给 OFDM通信通道单元。
9、 根据权利要求 8所述的扩频正交频分复用混合系统， 其特征在于， 所述的扩频 接收机包括： 接收天线、 放大器和下变频器单元、 直序扩频通信信道单元， 其中： 接收天线： 将从无线信道上接收到的信号发送给低躁放大器和下变频器单元； 低躁放大器和下变频器单元： 将接收天线发送过来的信号进行放大和下变频处理 后获得所述扩频通信信号， 将该扩频通信信号发送给直序扩频通信信道单元；
直序扩频通信信道单元： 将低躁放大器和下变频器单元发送过来的信号进行数字 解调， 通过扩频码序列进行扩频解调， 再将扩频解调后的信号进行窄带滤波、信道解码 处理后， 获得所述低躁放大器和下变频器单元发送过来的信号中携带的信令信息。
10、 根据权利要求 9所述的扩频正交频分复用混合系统， 其特征在于， 所述的扩频 接收机还包括：
信道估计单元： 用于估计扩频接收机的无线信道的时域和频域特性， 将获得的时 域和 /或频域的信道估计值传递给扩频通信信道单元。
11、 根据权利要求 8所述的扩频正交频分复用混合系统， 其特征在于， 所述的扩频 接收机包括： 接收天线、 放大器和下变频器单元、 跳频扩频通信信道单元， 其中： 接收天线： 将从无线信道上接收到的信号发送给低躁放大器和下变频器单元； 低躁放大器和下变频器单元： 将接收天线发送过来的信号进行放大和下变频处理 后获得所述扩频通信信号， 将该扩频通信信号发送给跳频扩频通信信道单元；
跳频扩频通信信道单元： 将低躁放大器和下变频器单元发送过来的信号和由本地 扩频码发生器产生的扩频码序列控制的频率合成器的输出频率进行混频，将混频处理后 的信号进行数字解调、信道解码， 获得所述低躁放大器和下变频器单元发送过来的信号 中携带的信令信息。
12、 根据权利要求 11所述的扩频正交频分复用混合系统， 其特征在于， 所述的扩 频接收机还包括：
信道估计单元： 用于估计扩频接收机的无线信道的时域和频域特性， 将获得的时 域和 /或频域的信道估计值传递给跳频扩频通信信道单元。
13、 根据权利要求 10或 12所述的扩频正交频分复用混合系统， 其特征在于， 所述 OFDM接收机中的上变频器和功放单元和扩频接收机中的上变频器和功放单元集成在一 起； 和 /或， 所述 OFDM接收机中的发射天线和扩频接收机中的发射天线集成在一起； 和 / 或， 所述 OFDM接收机中的信道估计单元和扩频接收机中的信道估计单元集成在一起。
14、 一种扩频正交频分复用混合方法， 其特征在于， 包括：
将第一信号进行正交频分复用处理获得 OFDM通信信号， 将第二信号进行扩频调制 处理获得扩频通信信号， 通过发射天线将所述扩频通信信号、 OFDM通信信号在共同占用 的频段上同时进行发送。
15、 根据权利要求 14所述的方法， 其特征在于， 所述方法还包括：
接收所述在共同占用的频段上同时发送的信号， 对该信号进行正交频分复用处理 获得所述发送前的第一信号； 对该信号进行扩频解调处理获得所述发送前的第二信号。
16、 根据权利要求 15所述的方法， 其特征在于， 所述将第一信号进行正交频分复 用处理获得 OFDM通信信号， 将第二信号进行扩频调制处理获得扩频通信信号具体包括： 将接收到的通信数据进行数字调制、 串并转换处理或串并转换、 数字调制处理后 转化为数据序列， 通过正交频分复用处理将该数据序列转化为时域序列， 在该时域序列 中插入循环前缀再进行并串转换处理， 获得所述 OFDM通信信号； 将接收到的信令信号进行信道编码， 通过扩频码序列进行调制， 再进行数字调制 处理获得所述扩频通信信号。
17、 根据权利要求 16所述的方法， 其特征在于， 所述接收所述在共同占用的频段 上同时发送的信号， 对该信号进行正交频分复用处理获得所述发送前的第一信号； 对该 信号进行扩频解调处理获得所述发送前的第二信号具体包括： 将从无线信道上接收到的信号进行放大和下变频处理后， 对该信号进行串并转换、 删除循环前缀处理后， ¾该信号进行正交频分复用处理后得到频域信号， 对该频域信号 进行数字解调、 并串转换处理或并串转换、 数字解调处理后， 再通过信道解码处理获得 '所述通信数据； 将从无线信道上接收到的信号进行放大和下变频处理后， 对该信号进行数字解调， 通过扩频码序列进行扩频解调，再将扩频解调后的信号进行窄带滤波、信道解码处理后， 获得所述信令信号。
18、 根据权利要求 15所述的方法， 其特征在于， 所述将第一信号进行正交频分复 用处理获得 0FDM通信信号， 将第二信号进行扩频调制处理获得扩频通信信号具体包括： 将接收到的通信数据进行数字调制、 串并转换处理或串并转换、 数字调制处理后 转化为数据序列， 通过正交频分复用处理将该数据序列转化为时域序列， 在该时域序列 中插入循环前缀再进行并串转换处理， 获得所述 OFDM通信信号； 将接收到的信令信号进行信道编码， 经过数字调制器进行调制处理， 再通过混频 器将数字调制器输出的信号和由扩频码发生器产生的扩频码序列控制的频率合成器的 输出频率进行混频处理， 获得所述扩频通信信号。
19、 根据权利要求 18所述的方法， 其特征在于， 所述接收所述在共同占用的频段 上同时发送的信号， 对该信号进行正交频分复用处理获得所述发送前的第一信号； 对该 信号进行扩频解调处理获得所述发送前的第二信号具体包括. - 将从无线信道上接收到的信号进行放大和下变频处理后， 对该信号进行正交频分 复用处理后得到频域信号， 对该频域信号进行数字解调、 并串转换处理或并串转换、 数 字解调处理后， 再通过信道解码处理获得所述通信数据； 将从无线信道上接收到的信号进行放大和下变频处理后， 将该信号和由本地扩频 码发生器产生的扩频码序列控制的频率合成器的输出频率进行混频，将混频处理后的信 号进行数字解调、 信道解码， 获得所述信令信号。
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