WO2011137795A1 - 降低光正交频分复用系统峰均功率比的方法、设备和系统 - Google Patents

降低光正交频分复用系统峰均功率比的方法、设备和系统 Download PDF

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WO2011137795A1
WO2011137795A1 PCT/CN2011/074371 CN2011074371W WO2011137795A1 WO 2011137795 A1 WO2011137795 A1 WO 2011137795A1 CN 2011074371 W CN2011074371 W CN 2011074371W WO 2011137795 A1 WO2011137795 A1 WO 2011137795A1
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frequency division
division multiplexing
orthogonal frequency
optical orthogonal
module
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PCT/CN2011/074371
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English (en)
French (fr)
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刘博�
忻向军
刘磊
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华为技术有限公司
北京邮电大学
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Publication of WO2011137795A1 publication Critical patent/WO2011137795A1/zh

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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2614Peak power aspects
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50Transmitters
    • H04B10/516Details of coding or modulation
    • H04B10/548Phase or frequency modulation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03828Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties
    • H04L25/03866Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties using scrambling

Definitions

  • the present invention relates to the field of optical communications, and more particularly to a method, apparatus and system for reducing the peak-to-average power ratio of an optical orthogonal frequency division multiplexing system.
  • Optical Orthogonal Frequency Division Multiplexing is a new transmission technology that combines OFDM and optical communication in wireless communication technology. It is essentially a modulation format and a carrier. Reuse method.
  • the basic working principle of OOFDM is: dividing a high-speed signal into several parallel low-speed signals (ie, OFDM symbols) in the time domain; at the same time, dividing the channel into several sub-channels in the frequency domain to form parallel multi-frequency subcarriers Each subcarrier is orthogonal to each other; by modulating each low-speed signal onto a different subcarrier, low-rate parallel transmission of low-rate signals on each subchannel is realized.
  • guard band For low-speed parallel subcarriers, the effect of delay spread is relatively reduced due to the widening of the symbol period. At the same time, a certain guard time (called guard band) can be inserted in each symbol, so that it can be almost ignored at the receiving end. Inter-symbol interference caused by fiber dispersion.
  • the peak-to-average power ratio (PAPR) of the OOFDM symbol is high, thereby generating a nonlinear effect, for example, four in the signal.
  • PAPR peak-to-average power ratio
  • the industry proposes a phase pre-compensation method to reduce the peak-to-average power ratio of the OOFDM symbol.
  • the specific scheme is: ignoring the dispersion effect in the optical fiber, by adding the inverse in the digital signal processing part of the OOFDM transmitter Trans-fiber link effect.
  • the nonlinear pre-compensation is loaded after the inverse Fourier transform module in the OOFDM transmitter to phase predistort each subcarrier of the inverse Fourier transformed OFDM signal. Due to this phase predistortion and fiber The phase effect brought about by the nonlinear effect is just the opposite, so the purpose of suppressing the nonlinear effect of the fiber can be achieved.
  • phase pre-compensation method is based on the fiber channel environment of the dispersion-free compensation link.
  • a strong negative dispersion causes a sharp narrowing of the pulses of the OFDM symbol.
  • the self-phase modulation caused by the change of signal strength causes many uncertain changes in the phase of each subcarrier, for example, contrary to the phase change caused by phase predistortion. As a result, the effect of phase predistortion is greatly Reduced.
  • phase predistortion needs to know the length of the optical fiber, and thus the phase predistortion according to the length of the optical fiber, which is not in line with the purpose of freely connecting the high speed network (the length of the transmitted optical fiber is variable).
  • Embodiments of the present invention provide a method, device, and system for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system to suppress nonlinear effects caused by peak-to-average power ratios.
  • An embodiment of the present invention provides a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system, where the method includes: generating m sets of orthogonal optical frequency divisions according to a random sequence of m groups of the same length generated by a scrambler Using a symbol, m is a natural number greater than 1, the m sets of optical orthogonal frequency division multiplexing symbols carrying the same information symbol; comparing peak-to-average power ratios of the m sets of orthogonal optical frequency division multiplexing symbols; A random sequence of peak-to-average power ratios, scrambling the information symbols to be transmitted to generate optical orthogonal frequency division multiplexing symbols.
  • An embodiment of the present invention provides a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system, where the method includes: restoring a received optical orthogonal frequency division multiplexing symbol to a binary sequence; according to the binary sequence, Determining a signal sequence sent by the transmitting end by using a Viterbi decoding based on a maximum likelihood criterion, wherein the signal sequence sent by the transmitting end includes a scrambling code and an information symbol; and removing the scrambling code included in the signal sequence sent by the transmitting end, The information symbol is obtained.
  • An embodiment of the present invention provides a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system, including an optical orthogonal frequency division multiplexing symbol generating module, a comparing module, and a scrambling code module; And a symbol generating module, configured to generate m sets of optical orthogonal frequency division multiplexing symbols according to the random sequence of m groups of the same length generated by the scrambling code module, where m is a natural number greater than 1, and the m sets of optical orthogonal frequencies
  • the sub-multiplexed symbol carries the same information symbol;
  • the comparing module is configured to compare peak-to-average power ratios of the m sets of optical orthogonal frequency division multiplexing symbols generated by the optical orthogonal frequency division multiplexing symbol generating module;
  • the scrambling code module is configured to scramble the information symbols to be transmitted by using a random sequence that generates a minimum peak-to-average power ratio according to the comparison result of the comparison module, so that
  • An embodiment of the present invention provides a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system, including a restoration module, a decoding module, and a descrambling code module.
  • the restoration module is configured to orthogonally receive the received optical Demultiplexing symbols are restored to a binary sequence;
  • the decoding module is configured to determine a signal sequence sent by the transmitting end by using Viterbi decoding based on a maximum likelihood criterion, and the signal sequence sent by the transmitting end includes a scrambling code and an information code
  • the descrambling code module is configured to remove the scrambling code included in the signal sequence sent by the sending end to obtain the information symbol.
  • Embodiments of the present invention provide a system for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system, including a transmitting device and a receiving device.
  • the transmitting device includes an optical orthogonal frequency division multiplexing symbol generating module, a comparison module, and a scrambling device.
  • a code module configured to generate m sets of optical orthogonal frequency division multiplexing symbols according to a random sequence of m groups of the same length generated by the scrambling code module, where m is greater than 1.
  • the comparing module configured to compare m sets of optical orthogonal frequency division generated by the optical orthogonal frequency division multiplexing symbol generating module Using a peak-to-average power ratio of the symbol
  • the scrambling code module is configured to: according to the comparison result of the comparison module, select a random sequence that generates a minimum peak-to-average power ratio, and scramble the information symbols to be transmitted, so that The optical orthogonal frequency division multiplexing symbol generating module generates an optical orthogonal frequency division multiplexing symbol
  • the receiving device includes a restoration module, a decoding module, and a descrambling code module; and the restoration module is configured to receive The optical orthogonal frequency division multiplexing symbol is restored to a binary sequence
  • the decoding module is configured to determine a signal sequence sent by the transmitting end by using Viterbi decoding based on a maximum likelihood criterion, and the signal sequence sent by the sending device includes the interference
  • the information symbols to be transmitted are scrambled by using a random sequence that generates a minimum peak-to-average power ratio, and a stable optical orthogonal frequency division multiplexing symbol is generated, and the optical orthogonal frequency division can be performed.
  • the peak-to-average power ratio of the multiplexed symbols is reduced to a minimum.
  • the method provided by the embodiment of the present invention selects a random sequence capable of generating a minimum peak-to-average power ratio.
  • the effect of the present invention is not affected by the optical fiber dispersion effect in the OOFDM system, even if it has dispersion In the OOFDM system for compensating optical fibers, the peak-to-average power ratio of the optical orthogonal frequency division multiplexing symbols can still be reduced, and a random sequence capable of generating a minimum peak-to-average power ratio is used to generate optical orthogonal frequency division multiplexing symbols, thereby eliminating peak currents.
  • the nonlinear effect of the power ratio extends the distance traveled by the fiber.
  • FIG. 1 is a schematic diagram of a basic flow of a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a basic flow of a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention
  • FIG. 3 is a schematic diagram of register state transition in convolutional coding represented by a state diagram
  • FIG. 4 is a schematic diagram of convolutional coding represented by a trellis diagram
  • FIG. 5 is a schematic diagram of a basic flow of a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention
  • FIG. 6 is a schematic diagram of a basic logical structure of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to an embodiment of the present invention
  • FIG. 7 is a schematic diagram of a basic logic structure of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention.
  • FIG. 8 is a schematic diagram of a basic logic structure of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention.
  • FIG. 9 is a schematic diagram of a basic logical structure of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention.
  • FIG. 10 is a schematic diagram of a basic logic structure of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention
  • FIG. 11 is a schematic structural diagram of a system for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to an embodiment of the present invention.
  • FIG. 1 is a schematic flowchart of a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to an embodiment of the present invention.
  • the action performer in this embodiment may be a transmitting device of an OOFDM system. Including steps:
  • m is a natural number greater than 1, and m sets of optical orthogonal frequency division multiplexing symbols carry the same information symbol.
  • the peak-to-average power ratios of the sets of optical orthogonal frequency division multiplexing symbols are not the same.
  • the basic principle and process of generating an optical orthogonal frequency division multiplexing symbol by a random sequence are the same as the basic principle and process of generating m sets of optical orthogonal frequency division multiplexing symbols according to the random sequence of the same m group length in step S101.
  • the difference is that the random sequence used in this step is a random sequence capable of producing a minimum peak-to-average power ratio.
  • the information symbols to be transmitted are scrambled by using a random sequence that generates a minimum peak-to-average power ratio, and a stable optical orthogonal frequency division multiplexing symbol is generated, and the optical orthogonal frequency division can be repeated.
  • the peak-to-average power ratio of the symbol is reduced to a minimum.
  • the method provided by the embodiment of the present invention generates an optical orthogonal frequency division multiplexing symbol by selecting a random sequence capable of generating a minimum peak-to-average power ratio, instead of using phase predistortion to cancel the nonlinear effect of the fiber.
  • the effect of the present invention is not affected by the fiber dispersion effect in the OOFDM system, and even in the OOFDM system with the dispersion compensation fiber, the peak-to-average power of the optical orthogonal frequency division multiplexing symbol can be reduced.
  • a random sequence capable of generating a minimum peak-to-average power ratio is used to generate an optical orthogonal frequency division multiplexing symbol, thereby eliminating the nonlinear effect caused by the peak-to-average power ratio and prolonging the distance of the optical fiber transmission, which will be described in detail below.
  • a basic flow chart of a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system includes the following steps:
  • the scrambler generates a random sequence of the same length of the m group
  • m is a natural number greater than one.
  • the m-group random sequences having the same length may be sequentially inserted into the beginning of the data frame (the data frame contains the same information symbol), and the m-group digital sequences carry the same information symbol ( That is useful information). Due to the randomness of the random sequences, these m sets of numerical sequences are independent of each other.
  • each set of digital sequences in the m-group digital sequence can be transformed into a m-group mapping sequence by convolutional coding.
  • the convolutional encoding process provided by this embodiment is similar to the selective mapping process, i.e., essentially multiplying information symbol I by a different random sequence.
  • the information symbol I after the convolutional coding becomes a digital sequence in which the m-group mapping method is different.
  • the encoding circuit of the convolutional code can usually be regarded as a linear circuit with a finite state, so the state diagram can be used to describe the encoding process.
  • the value of the data stored in the encoder register at any one time A state called an encoder, since it is represented.
  • the state of the registers in the encoder transitions between the above four states and the corresponding code sequence is output.
  • the number before the oblique line indicates the input symbol, followed by the corresponding output symbol.
  • the encoder is from S.
  • the state transitions to state and the encoder output is 11.
  • the state diagram shown in Fig. 3 is expanded in chronological order to obtain a trellis diagram of the convolutional code, as shown in Fig. 4.
  • a trellis diagram of the convolutional code As shown in Fig. 4.
  • the input information sequence corresponding to the thick line in Fig. 4 is (1011100), and the corresponding code output is (11, 10, 00, 01, 10, 01, 11).
  • Convolutionally encoded trellis diagram structure is mainly used for analysis of convolutional code encoding process and Viterbi (Viterbi) decoding.
  • a trellis diagram of the convolutional code can represent the relationship of the encoder state transition to time.
  • the information symbols are segmented, and every L segments (k. L) of information symbols are followed by k. m fixed (generally k G m '0') information symbols are sent to the encoder code.
  • the decoder automatically translates it into k. m sequence of information symbols originally transmitted. This ensures that every L segment must have correct decoding of consecutive m segments, thus limiting error propagation to L+m segments.
  • the m group mapping sequence obtained in step S203 is sequentially subjected to serial-to-parallel transformation, constellation mapping, inverse Fourier transform, load cyclic prefix, and parallel-to-serial conversion to obtain m sets of optical orthogonal frequency division multiplexing symbols.
  • the optical orthogonal frequency division multiplexing symbol with the smallest peak-to-average power ratio is fed back to the scrambler.
  • the scrambler receives the peak-to-average power ratio of the feedback to the smallest optical orthogonal frequency division multiplexing symbol, thereby determining a random sequence used when scrambling the information symbols to be transmitted.
  • the subsequent process is similar to steps S202 to S204, that is, a random sequence that produces a minimum peak-to-average power ratio and the required transmission
  • the information symbols are mixed into a digital sequence; the mixed digital sequence is mapped into a mapping sequence; the mapping sequence is sequentially subjected to serial-to-parallel conversion, constellation mapping, inverse Fourier transform, load cyclic prefix and parallel-to-serial conversion to obtain optical orthogonal frequency
  • the sub-multiplexed symbol, this optical orthogonal frequency division multiplexing symbol is an optical orthogonal frequency division multiplexing symbol with a minimum peak-to-average power ratio.
  • the random sequence used in the scrambling code for determining the information symbol to be transmitted in step S207 is a relatively stable behavior for a period of time.
  • the steps before step S207 may be repeated to reselect the optical orthogonal frequency capable of generating the minimum peak-to-average power ratio in the m-group random sequence.
  • a random sequence of sub-multiplexed symbols that is, a random sequence that can be used once every once in a while, embodies the adaptability of the system.
  • FIG. 5 is a schematic flowchart of a method for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention.
  • the action performer in this embodiment may be an OOFDM system.
  • the optical orthogonal frequency division multiplexing symbols may be sequentially subjected to serial-to-parallel conversion, de-cyclic prefix, Fourier transform, constellation demodulation, and parallel-to-serial conversion, thereby being restored to a binary sequence.
  • the signal sequence sent by the sending device includes the scrambling code and the information symbol (ie, useful information) to be transmitted.
  • the method specifically includes: converting the binary sequence obtained by the optical orthogonal frequency division multiplexing symbol to all possible transmissions of the transmitting device.
  • the signal sequence is compared; the signal sequence with the smallest Hamming Distance obtained by the comparison result is determined as the signal sequence sent by the transmitting end.
  • Decoder e.g., from a certain state from the state [alpha], each extending a right branch (power are possible extension for 1 ⁇ L, starting from each node 2 of 2, where L is the information sequence The number of segments, for 1 ⁇ L, has only one possibility), and is compared with the corresponding branch of the received data, calculating the distance between them, and then adding the calculated distance to the cumulative distance value of the extended path.
  • the decoder gets the path with the largest path metric. From time unit m to L, there is a surviving path for each of the two states in the grid map, for a total of two. However, after the L time unit (node), the number of states on the grid map is reduced, and the surviving path is also reduced accordingly. Finally, to the L+m unit time, the grid map is returned to the state S 0 which is all 0 , so only one surviving path remains. This path is the path with the largest likelihood function, that is, the sequence of evaluation codes output by the decoder.
  • the receiving device side must know the mapping mode of the transmitting device side, that is, the mapping factor of the transmitting device is transmitted together with the information symbol in the form of a label, which increases the redundancy of the system. Therefore, compared with the existing selective mapping (SLM, SLective Mapping), the receiving device does not need any edge information, that is, the information symbol sent by the transmitting device can be obtained without knowing the mapping sequence on the transmitting device side. Thereby greatly improving the efficiency of the system.
  • SLM selective mapping
  • FIG. 6 a basic logical structure diagram of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to an embodiment of the present invention is provided.
  • the device shown in FIG. 6 may be a transmitting device of an OOFDM system, including an optical orthogonal frequency division multiplexing symbol generating module 601, a comparing module 602, and a scrambling code module 603, where: an optical orthogonal frequency division multiplexing symbol generating module 601, The m sets of optical orthogonal frequency division multiplexing symbols are generated according to the random sequence of m groups of the same length generated by the scrambling code module 603.
  • m is a natural number greater than 1, and m sets of optical orthogonal frequency division multiplexing symbols carry the same information symbol.
  • the comparing module 602 is configured to compare peak-to-average power ratios of the m sets of optical orthogonal frequency division multiplexing symbols generated by the optical orthogonal frequency division multiplexing symbol generating module 601.
  • the scrambling code module 603 is configured to: according to the comparison result of the comparison module 602, select a random sequence that generates a minimum peak-to-average power ratio, and scramble the information symbols to be transmitted, so that the optical orthogonal frequency division multiplexing symbol generation module 601 generates an optical orthogonal frequency division multiplexing symbol.
  • the scrambling code module 603 shown in FIG. 6 is further configured to generate a random sequence of m groups of the same length.
  • the optical orthogonal frequency division multiplexing symbol generating module 601 further includes a mixing unit 701, a mapping unit 702, a serial-to-parallel transform unit 703, and a constellation mapping unit. 704, an inverse Fourier transform unit 705, a prefix loading unit 706, and a parallel-to-serial transform unit 707, as shown in FIG.
  • a device for reducing the peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention , among them: a mixing unit 701, configured to mix the m-group random sequences generated by the scrambling code module 603 with the same information symbol to obtain an m-group digital sequence;
  • mapping unit 702 configured to map the m-group digital sequence obtained by mixing the mixing unit 701 into a m-group mapping sequence
  • the serial-to-parallel transform unit 703, the constellation mapping unit 704, the inverse Fourier transform unit 705, the prefix loading unit 706, and the parallel-to-serial transform unit 707 are sequentially used to perform the serial-to-parallel conversion, constellation mapping, and mapping of the m-group mapping sequences mapped by the mapping unit 702.
  • the inverse Fourier transform, the loaded cyclic prefix, and the parallel-to-serial transform obtain m sets of optical orthogonal frequency division multiplexing symbols.
  • FIG. 8 a basic logical structure diagram of a device for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system according to another embodiment of the present invention is provided. For the convenience of description, only the parts related to the embodiment of the present invention are shown.
  • the device shown in FIG. 8 may be a receiving device of the OOFDM system, and includes a restoration module 801, a decoding module 802, and a descrambling code module 803, where:
  • the restoration module 801 is configured to restore the received optical orthogonal frequency division multiplexing symbols into a binary sequence.
  • the decoding module 802 is configured to restore the obtained binary sequence according to the restoration module 801, and determine the Viterbi decoding based on the maximum likelihood criterion.
  • a signal sequence sent by the transmitting end, and the signal sequence sent by the transmitting end includes a scrambling code and an information symbol;
  • the descrambling code module 803 is configured to remove the scrambling code included in the signal sequence sent by the transmitting end to obtain the information symbol.
  • the restoration module 801 shown in FIG. 8 further includes a serial-to-parallel transform unit 901, a de-cyclic prefix unit 902, a Fourier transform unit 903, a constellation demodulation unit 904, and a parallel-to-serial conversion unit 905, as shown in FIG.
  • the apparatus for reducing the peak-to-average power ratio of an optical orthogonal frequency division multiplexing system provided by the embodiment, wherein:
  • serial-to-parallel transform unit 901, the de-cyclic prefix unit 902, the Fourier transform unit 903, the constellation demodulation unit 904, and the parallel-to-serial transform unit 905 are sequentially used to perform serial-to-parallel conversion and de-cyclic prefix on optical orthogonal frequency division multiplexing symbols. , Fourier transform, constellation demodulation, and parallel-to-serial conversion.
  • the decoding module 802 shown in FIG. 8 further includes a comparing unit 1001 and a determining unit 1002. As shown in FIG. 10, another apparatus for reducing the peak-to-average power ratio of the optical orthogonal frequency division multiplexing system is provided in FIG.
  • Comparison unit 1001 for using a binary sequence obtained by reducing optical orthogonal frequency division multiplexing symbols Compare with all possible signal sequences sent by the sender;
  • the determining unit 1002 is configured to determine, by the comparison unit 1001, a signal sequence whose Hamming distance is the smallest, and determine a signal sequence transmitted by the transmitting end.
  • a system for reducing a peak-to-average power ratio of an optical orthogonal frequency division multiplexing system includes a transmitting device 1101 illustrated in FIG. 6 and a receiving device 1102 illustrated in FIG. 8.
  • the transmitting device 1101 includes an optical orthogonal frequency division multiplexing symbol generating module 601, a comparing module 602, and a scrambling code module 603, where:
  • the optical orthogonal frequency division multiplexing symbol generating module 601 is configured to generate m sets of optical orthogonal frequency division multiplexing symbols according to the random sequence of m groups of the same length generated by the scrambling code module 603;
  • the comparing module 602 is configured to compare peak-to-average power ratios of the m sets of optical orthogonal frequency division multiplexing symbols generated by the optical orthogonal frequency division multiplexing symbol generating module 601;
  • the scrambling code module 603 is configured to scramble the information symbols to be transmitted according to the comparison result of the comparison module 602 by using a random sequence that generates a minimum peak-to-average power ratio, so that the optical orthogonal frequency division multiplexing symbols are generated.
  • Module 601 generates optical orthogonal frequency division multiplexing symbols;
  • the receiving device 1102 includes a restoration module 801, a decoding module 802, and a descrambling code module 803, where: a restoration module 801, configured to restore the received optical orthogonal frequency division multiplexing symbols into a binary sequence; and a decoding module 802, configured to: The restored binary sequence is restored according to the restoration module 801, and the Viterbi decoding based on the maximum likelihood criterion is used to determine the signal sequence sent by the transmitting end, and the signal sequence transmitted by the transmitting end includes the scrambling code and the information symbol;
  • the descrambling code module 803 is configured to remove the scrambling code included in the signal sequence sent by the transmitting end to obtain an information symbol.

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Description

降低光正交频分复用系统峰均功率比的方法、 设备和系统 本申请要求于 2010 年 9 月 6 日提交中国专利局、 申请号为 201010275213.7、发明名称为"降低光正交频分复用系统峰均功率比的方法、 设备和系统" 的中国专利申请的优先权, 其全部内容通过引用结合在本申 请中。 技术领域
本发明涉及光通信领域, 尤其涉及降低光正交频分复用系统峰均功率 比的方法、 设备和系统。
背景技术
光正交频分复用 ( OOFDM , Optical Orthogonal Frequency Division Multiplexing )是将无线通信技术中的 OFDM与光通信相融合而成的新型传 输技术, 其本质上是一种调制格式, 同时也是一种载波复用方式。 OOFDM 的基本工作原理是: 将高速信号在时域上分成若干并行的低速信号 (即 OFDM符号); 与此同时, 在频域上将信道划分为若干子信道, 形成并行的 多分频子载波, 各子载波之间是相互正交的; 通过将每路低速信号调制到 不同的子载波上, 实现低速信号在每个子信道上的低码率并行传输。 对于 低速的并行子载波而言, 由于符号周期展宽, 时延扩展的影响相对减小, 同时可以在每个符号中插入一定的保护时间 (称为保护带) , 这样, 在接 收端几乎可以忽略光纤色散导致的码间干扰。
然而, 正是由于各个子载波之间的正交性、 高相干性, OOFDM符号的 峰均功率比( PAPR, Peak Average Peak Ratio )很高, 由此产生非线性效应, 例如, 信号内的四波混频、 单一信道的自相位调制或多信道间的交叉相位 调制等等, 这些非线性效应都严重制约了系统的传输距离。
针对上述 OOFDM系统存在的问题,业界提出一种基于相位预补偿方式 来降低 OOFDM符号的峰均功率比, 具体方案是: 忽略光纤中的色散效应, 通过在 OOFDM发射机的数字信号处理部分加入反转光纤链路效应。非线性 预补偿加载在 OOFDM发射机中的反傅里叶变换模块之后,使反傅里叶变换 后的 OFDM信号的各个子载波发生相位预畸变。由于这种相位预畸变与光纤 非线性效应所带来的相位作用刚好相反, 因此, 可以达到抑制光纤非线性 作用的目的。
发明人经过对上述现有技术的研究发现, 这种基于相位预补偿方式是 以无色散补偿链路的光纤信道环境为前提条件。 在具有色散补偿光纤的系 统中,强烈的负色散会带来 OFDM符号的脉沖急剧变窄。信号强度的变化所 带来的自相位调制作用, 使得各个子载波的相位发生众多不确定的变化, 例如, 与相位预畸变所带来的相位变化相反, 结果使得相位预畸变产生的 作用大为减小。
进一步地, 相位预畸变需要了解光纤的长度, 从而依据光纤长度进行 相位预畸变, 这并不符合未来高速网络可自由上下路(所传光纤长度可变 ) 的宗旨。
发明内容
本发明实施例提供一种降低光正交频分复用系统峰均功率比的方法、 设备和系统, 以抑制由高峰均功率比带来的非线性效应。
本发明实施例提供一种降低光正交频分复用系统峰均功率比的方法, 所述方法包括: 根据扰码器产生的 m组长度相同的随机序列生成 m组光正交 频分复用符号, m为大于 1的自然数, 所述 m组光正交频分复用符号携带相 同信息码元; 比较所述 m组光正交频分复用符号的峰均功率比; 选用产生最 小峰均功率比的随机序列, 将所需传输的信息码元进行扰码, 以生成光正 交频分复用符号。
本发明实施例提供一种降低光正交频分复用系统峰均功率比的方法, 所述方法包括: 将接收的光正交频分复用符号还原成二进制序列; 根据所 述二进制序列, 采用基于最大似然准则的维特比译码确定发送端发送的信 号序列, 所述发送端发送的信号序列包含扰码和信息码元; 去除所述发送 端发送的信号序列中包含的扰码, 得到所述信息码元。
本发明实施例提供一种降低光正交频分复用系统峰均功率比的设备, 包括光正交频分复用符号生成模块、 比较模块和扰码模块; 所述光正交频 分复用符号生成模块,用于根据所述扰码模块产生的 m组长度相同的随机序 列生成 m组光正交频分复用符号, m为大于 1的自然数, 所述 m组光正交频 分复用符号携带相同信息码元; 所述比较模块, 用于比较所述光正交频分 复用符号生成模块生成的 m组光正交频分复用符号的峰均功率比;所述扰码 模块, 用于根据所述比较模块的比较结果, 选用产生最小峰均功率比的随 机序列将所需传输的信息码元进行扰码, 以使所述光正交频分复用符号生 成模块生成光正交频分复用符号。
本发明实施例提供一种降低光正交频分复用系统峰均功率比的设备, 包括还原模块、 译码模块和去扰码模块; 所述还原模块, 用于将接收的光 正交频分复用符号还原成二进制序列; 所述译码模块, 用于采用基于最大 似然准则的维特比译码确定发送端发送的信号序列, 所述发送端发送的信 号序列包含扰码和信息码元; 所述去扰码模块, 用于去除所述发送端发送 的信号序列中包含的扰码得到所述信息码元。
本发明实施例提供一种降低光正交频分复用系统峰均功率比的系统, 包括发送设备和接收设备; 所述发送设备包括光正交频分复用符号生成模 块、 比较模块和扰码模块; 所述光正交频分复用符号生成模块, 用于根据 所述扰码模块产生的 m组长度相同的随机序列生成 m组光正交频分复用符 号, m为大于 1的自然数,所述 m组光正交频分复用符号携带相同信息码元; 所述比较模块,用于比较所述光正交频分复用符号生成模块生成的 m组光正 交频分复用符号的峰均功率比; 所述扰码模块, 用于根据所述比较模块的 比较结果, 选用产生最小峰均功率比的随机序列, 将所需传输的信息码元 进行扰码, 以使所述光正交频分复用符号生成模块生成光正交频分复用符 号; 所述接收设备包括还原模块、 译码模块和去扰码模块; 所述还原模块, 用于将接收的光正交频分复用符号还原成二进制序列; 所述译码模块, 用 于采用基于最大似然准则的维特比译码确定发送端发送的信号序列, 所述 发送设备发送的信号序列包含扰码和信息码元; 所述去扰码模块, 用于去 除所述发送设备发送的信号序列中包含的扰码得到所述信息码元。
在本发明提供的实施例中, 通过选用产生最小峰均功率比的随机序列 将需要传输的信息码元进行扰码, 生成稳定的光正交频分复用符号, 可以 将光正交频分复用符号的峰均功率比降低到最小。 与现有技术相比, 由于 本发明实施例提供的方法是通过选用能够产生最小峰均功率比的随机序列 来产生光正交频分复用符号, 而不是采用相位预畸变抵消光纤非线性效应 所带来的相位作用, 因此, 本发明的效果不受 OOFDM系统中光纤色散效应 的影响, 即使在具有色散补偿光纤的 OOFDM系统中, 仍然可以降低光正交 频分复用符号的峰均功率比, 选用能够产生最小峰均功率比的随机序列来 产生光正交频分复用符号, 从而消除高峰均功率比带来的非线性效应, 延 长光纤传输的距离。
附图说明
为了更清楚地说明本发明实施例的技术方案, 下面将对现有技术或实 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, 还可以如这些附图获得其他的附图。
图 1是本发明实施例提供的一种降低光正交频分复用系统峰均功率比 的方法基本流程示意图;
图 2本发明另一实施例提供的一种降低光正交频分复用系统峰均功率 比的方法基本流程示意图;
图 3是使用状态图表示的卷积编码中寄存器状态转移示意图; 图 4是使用网格图表示的卷积编码示意图;
图 5是本发明另一实施例提供的降低光正交频分复用系统峰均功率比 的方法基本流程示意图;
图 6是本发明实施例提供的一种降低光正交频分复用系统峰均功率比 的设备基本逻辑结构示意图;
图 7是本发明另一实施例提供的一种降低光正交频分复用系统峰均功 率比的设备基本逻辑结构示意图;
图 8是本发明另一实施例提供的一种降低光正交频分复用系统峰均功 率比的设备基本逻辑结构示意图;
图 9是本发明另一实施例提供的一种降低光正交频分复用系统峰均功 率比的设备基本逻辑结构示意图;
图 10是本发明另一实施例提供的一种降低光正交频分复用系统峰均功 率比的设备基本逻辑结构示意图; 图 11是本发明实施例提供的一种降低光正交频分复用系统峰均功率比 的系统结构示意图。
具体实肺式
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。
请参阅附图 1, 是本发明实施例提供的一种降低光正交频分复用系统峰 均功率比的方法基本流程示意图,本实施例的动作执行者可以是 OOFDM系 统的发送设备, 主要包括步骤:
5101 , 根据扰码器产生的 m组长度相同的随机序列, 生成 m组光正交频 分复用符号。
在本实施例中, m是一个大于 1的自然数, 并且, m组光正交频分复用 符号携带相同信息码元。
5102, 比较生成的 m组光正交频分复用符号的峰均功率比。
虽然 m组光正交频分复用符号携带相同信息码元,但各组光正交频分复 用符号的峰均功率比并不相同。
5103 , 选用产生最小峰均功率比的随机序列, 将所需传输的信息码元 进行 4尤码, 以生成光正交频分复用符号。
本步骤中, 由随机序列生成光正交频分复用符号的基本原理、 过程与 步骤 S101中根据 m组长度相同的随机序列生成 m组光正交频分复用符号的 基本原理、 过程相同, 不同之处在于, 本步骤中使用的随机序列是能够产 生最小峰均功率比的随机序列。
由上述本发明实施例可知, 通过选用产生最小峰均功率比的随机序列 将需要传输的信息码元进行扰码, 生成稳定的光正交频分复用符号, 可以 将光正交频分复用符号的峰均功率比降低到最小。 与现有技术相比, 由于 本发明实施例提供的方法是通过选用能够产生最小峰均功率比的随机序列 来产生光正交频分复用符号, 而不是采用相位预畸变抵消光纤非线性效应 所带来的相位作用, 因此, 本发明的效果不受 OOFDM系统中光纤色散效应 的影响, 即使在具有色散补偿光纤的 OOFDM系统中, 仍然可以降低光正交 频分复用符号的峰均功率比, 选用能够产生最小峰均功率比的随机序列来 产生光正交频分复用符号, 从而消除高峰均功率比带来的非线性效应, 延 长光纤传输的距离, 以下详细说明。
请参阅图 2, 本发明另一实施例提供的一种降低光正交频分复用系统峰 均功率比的方法基本流程示意图, 主要包括步骤:
S201 , 扰码器生成 m组长度相同的随机序列;
在本实施例中, m是一个大于 1的自然数。
S202,将生成的 m组长度相同的随机序列与相同信息码元混合得到 m组 数字序列。
对于步骤 S202,具体地,可以将该 m组长度相同的随机序列逐次插入数 据帧(数据帧包含的是相同信息码元)的开始部分, 这些 m组数字序列就携 带了相同的信息码元(即有用信息)。 由于随机序列的随机性, 因此, 这些 m组数字序列是相互独立的。
S203 , 将步骤 S202中混合所得的 m组数字序列映射成 m组映射序列。 在本实施例中,可以将 m组数字序列中的每一组数字序列通过卷积编码 变换成 m组映射序列。
由于卷积编码所产生的码元不仅与当前时间段的信息码元有关, 还与 之前所有时间段的信息码元有关, 因此, 携带有不同比特起始序列的数据 帧经历了不同的映射方式。 本实施例提供的卷积编码过程, 与选择性映射 过程类似, 即, 本质上是将信息码元 I乘以不同的随机序列。 经过卷积编码 之后的信息码元 I, 就成为 m组映射方式不同的数字序列。
将卷积编码应用至 OOFDM系统中,通过卷积编码所造成的子载波相位 的变化降低了子载波之间的相关度。
为了下文更加清楚地说明本发明的技术方案, 对卷积编码做简要说明 ^口下:
卷积码的编码电路通常可以看作一个有限状态的线性电路, 因此可以 利用状态图来描述编码过程。 编码器寄存器在任一时刻所存储的数据取值 称为编码器的一个状态, 以 来表示。 对于图 2所示的二进制(2、 1、 2 )卷 积码, 编码器中包含两个寄存器, 因此, 共有 22 =4种可能状态, 相应的取 值和标记如下表一所示。
随着信息序列的输入, 编码器中寄存器的状态在上述四个状态之间发 生转移, 并输出相应的码序列。 将编码器随输入而发生状态转移的过程用 流程图的
形式来描述, 即得到卷积码的状态图。 以 (2、 1、 2 )卷积码为例, 其状态 图及相应的输入码元的关系如附图 3所示。
Figure imgf000009_0001
表一
在附图 3中, 对应每一条转移路径上的标记, 斜线前的数码表示输入码 元, 后面是相应的输出码元。 例如, 若当前编码器处于 状态, 下一时刻 输入为 1时, 编码器从 S。状态转移到 状态, 同时编码器输出为 11。 编码器 的编码过程就是在状态图上转移的过程。 例如, 对于信息序列 m = ( 1011100 ), 若卷积码的初始状态为 , 则在对 m编码时的状态转移为 So 相应的编码输出为 (11, 10, 00, 01 , 10, 01 , 11 )。
将附图 3所示状态图按照时间的顺序展开, 即得到卷积码的网格图, 如 附图 4所示。 例如, 考察长度为 L=5的输入信息序列, 为使编码器在编码完 成后回到初始 SO状态, 需要在信息序列的尾端补存与编码器寄存器个数相 等的零比特, 其中,每条路径转移分支对应的输入 /输出码元与附图 4给出的 状态图是一致的。 附图 4中粗线所对应的输入信息序列为 (1011100 ), 相应 的编码输出为 (11, 10, 00, 01 , 10, 01 , 11 )。
卷积编码的网格图结构主要用于对卷积码编码过程的分析和维特比 ( Viterbi )译码。
卷积码的网格图可表示出编码器状态转移与时间的关系。 编码时, 将 信息码元分段, 每隔 L段 (k。L个)信息码元后, 跟着将 k。m个固定不变的 (一 般是 kGm个 '0' )信息码元送入编码器编码。 译码时, 每当这 kGm个确知信 息码元所对应的码序列到达译码器并被译码器识别后, 译码器就自动将其 译为 k。m个原先发送的信息码元序列。 这样就保证每隔 L段必有连续 m段的 正确译码, 因而使误差传播限制在 L+m段内。
5204, 将步骤 S203中所得 m组映射序列依次经过串并变换、 星座映射、 反傅里叶变换、 加载循环前缀和并串变换后得到 m组光正交频分复用符号。
本步骤中, 串并变换和星座映射等均与现有技术的方案相同, 不做赘 述。
5205, 比较 m组光正交频分复用符号的峰均功率比。
S206, 将峰均功率比最小的光正交频分复用符号反馈至扰码器。
S207, 扰码器接收反馈的峰均功率比最小的光正交频分复用符号, 由 此确定对所需传输的信息码元进行扰码时使用的随机序列。
扰码器确定了对所需传输的信息码元进行扰码时使用的随机序列之 后, 后续过程与步骤 S202至步骤 S204类似, 即, 将产生最小峰均功率比的 随机序列与所需传输的信息码元混合成数字序列; 将混合后所得数字序列 映射成映射序列; 将映射序列依次经过串并转换、 星座映射、 反傅里叶变 换、 加载循环前缀和并串变换后得到光正交频分复用符号, 这个光正交频 分复用符号就是峰均功率比最小的光正交频分复用符号。
需要说明的是, 在上述实施例中, 步骤 S207中确定所需传输的信息码 元进行扰码时使用的随机序列是一段时间相对稳定的行为。 例如, 考虑到 网络环境的变化, 在使用步骤 S207中确定的随机序列一段时间后, 可以重 复步骤 S207之前的步骤,重新选出 m组随机序列中能够产生最小峰均功率比 的光正交频分复用符号的随机序列, 即, 可以每隔一段时间变化一次使用 的随机序列, 体现了系统的自适应性。
请参阅图 5, 本发明另一实施例提供的降低光正交频分复用系统峰均功 率比的方法基本流程示意图,本实施例的动作执行者可以是 OOFDM系统的 接收设备, 主要包括步骤:
5501 , 将接收的光正交频分复用符号还原成二进制序列。
具体地, 在接收设备侧, 可以将光正交频分复用符号依次经过串并变 换、 去循环前缀、 傅里叶变换、 星座解调和并串变换, 从而还原成二进制 序列。
5502,根据所述二进制序列,采用基于最大似然准则的维特比( Viterbi ) 译码确定发送设备发送的信号序列。
发送设备发送的信号序列包含扰码和所需传输的信息码元(即有用信 息), 对于本步骤, 具体包括: 将由光正交频分复用符号还原所得的二进制 序列与发送设备所有可能发送的信号序列比较; 由比较结果得到汉明距离 ( Haimin Distance )最小的信号序列确定为发送端发送的信号序列。
以下对 S502的技术方案做进一步的说明。
与运筹学中求最短路径的算法相类似, 若从接收的光正交频分复用符 号还原所得二进制序列为 R = 10100101100111。 译码器从某个状态, 例如, 从状态 α 出发, 每次向右延伸一个分支(对于 1 < L, 从每个节点出发都有 2 的 2次幂种可能的延伸, 其中 L是信息序列段数, 对 1≥L, 只有一种可能), 并与接收数据相应分支进行比较, 计算它们之间的距离, 然后将计算所得 距离加到被延伸路径的累积距离值中。 对到达每个状态的各条路径 (总共 有 2的 2次幂条) 的距离累积值进行比较, 保留距离值最小的一条路径, 称 为幸存路径(当有两条以上取最小值时, 可任取其中之一)。 上述算法过程 简述如下:
1、 从某一时间单位 j = m开始, 对进入每一状态的所有长为 j段分支的 部分路径, 计算部分路径度量。 对每一状态, 挑选并存储一条有最大度量 的部分路径及其部分度量值, 称此部分路径为幸存路径;
2、 j增加 1, 把此时刻进入每一状态的所有分支度量, 和同这些分支相 连的前一时刻的幸存路径的度量相加, 得到了此时刻进入每一状态的幸存 路径, 加以存储并删去其它所有路径, 因此幸存路径延长了一个分支;
3、 ¾ < L + m, 则重复以上各步, 否则停止, 译码器得到了有最大路 径度量的路径。 由时间单位 m直到 L, 网格图中 2 个状态中的每一个有一条幸存路径, 共有 2 条。 但在 L时间单位(节点)后, 网格图上的状态数目减少, 幸存 路径也相应减少。 最后到第 L+m单位时间, 网格图归到全为 0的状态 S0, 因 此仅剩下一条幸存路径。 这条路径就是要找的具有最大似然函数的路径, 也就是译码器输出的估值码序列 έ。
S503 , 去除发送端发送的信号序列中包含的扰码得到信息码元。
在现有技术中, 接收设备侧必须知道发送设备侧的映射方式, 也就是 发送设备的映射因子要以标签的形式与信息码元一起传出来, 这增加了系 统的冗余度。 因此, 与现有的选择性映射( SLM, SLective Mapping )相比, 接收设备不需要任何的边缘信息, 即, 不需要知道发送设备侧的映射序列, 就能得到发送设备发送的信息码元, 从而较大地提升系统的效率。
请参阅图 6,本发明实施例提供的一种降低光正交频分复用系统峰均功 率比的设备基本逻辑结构示意图。 为了便于说明, 仅仅示出了与本发明实 施例相关的部分。 图 6所示设备可以是 OOFDM系统的发送设备, 包括光 正交频分复用符号生成模块 601、 比较模块 602和扰码模块 603, 其中: 光正交频分复用符号生成模块 601,用于根据扰码模块 603产生的 m组长 度相同的随机序列生成 m组光正交频分复用符号。
本实施例中, m为大于 1的自然数, m组光正交频分复用符号携带相同 信息码元。
比较模块 602,用于比较光正交频分复用符号生成模块 601生成的 m组光 正交频分复用符号的峰均功率比。
扰码模块 603, 用于根据比较模块 602的比较结果, 选用产生最小峰均 功率比的随机序列, 将所需传输的信息码元进行扰码, 以使光正交频分复 用符号生成模块 601生成光正交频分复用符号。
图 6所示扰码模块 603还用于生成 m组长度相同的随机序列,光正交频分 复用符号生成模块 601进一步包括混合单元 701、 映射单元 702、 串并变换单 元 703、 星座映射单元 704、 反傅里叶变换单元 705、 前缀加载单元 706和并 串变换单元 707, 如附图 7所示本发明另一实施例提供的降低光正交频分复 用系统峰均功率比的设备, 其中: 混合单元 701,用于将扰码模块 603生成的 m组长度相同的随机序列与同 一信息码元混合得到 m组数字序列;
映射单元 702, 用于将混合单元 701混合所得 m组数字序列映射成 m组映 射序列;
串并变换单元 703、 星座映射单元 704、 反傅里叶变换单元 705、 前缀加 载单元 706和并串变换单元 707依次用于将映射单元 702映射所得 m组映射序 列进行串并变换、 星座映射、 反傅里叶变换、 加载循环前缀和并串变换后 得到 m组光正交频分复用符号。
请参阅图 8, 本发明另一实施例提供的一种降低光正交频分复用系统峰 均功率比的设备基本逻辑结构示意图。 为了便于说明, 仅仅示出了与本发 明实施例相关的部分。 图 8所示设备可以是 OOFDM系统的接收设备, 包括 还原模块 801、 译码模块 802和去扰码模块 803, 其中:
还原模块 801, 用于将接收的光正交频分复用符号还原成二进制序列; 译码模块 802, 用于根据还原模块 801还原所得二进制序列, 采用基于 最大似然准则的维特比译码确定发送端发送的信号序列, 发送端发送的信 号序列包含扰码和信息码元;
去扰码模块 803, 用于去除发送端发送的信号序列中包含的扰码得到信 息码元。
图 8所示还原模块 801进一步包括串并变换单元 901、 去循环前缀单元 902、 傅里叶变换单元 903、 星座解调单元 904和并串变换单元 905, 如附图 9 所示本发明另一实施例提供的降低光正交频分复用系统峰均功率比的设 备, 其中:
串并变换单元 901、 去循环前缀单元 902、 傅里叶变换单元 903、 星座解 调单元 904和并串变换单元 905依次用于对光正交频分复用符号进行串并变 换、 去循环前缀、 傅里叶变换、 星座解调和并串变换。
图 8所示译码模块 802进一步包括比较单元 1001和确定单元 1002, 如附 图 10所示本发明另一实施例提供的降低光正交频分复用系统峰均功率比的 设备, 其中:
比较单元 1001, 用于将由光正交频分复用符号还原所得的二进制序列 与发送端所有可能发送的信号序列比较;
确定单元 1002, 用于由比较单元 1001比较结果得到汉明距离最小的信 号序列确定为发送端发送的信号序列。
请参阅图 11, 本发明实施例提供的一种降低光正交频分复用系统峰均 功率比的系统, 包括图 6示例的发送设备 1101和图 8示例的接收设备 1102。
发送设备 1101包括光正交频分复用符号生成模块 601、 比较模块 602和 扰码模块 603, 其中:
光正交频分复用符号生成模块 601,用于根据扰码模块 603产生的 m组长 度相同的随机序列生成 m组光正交频分复用符号;
比较模块 602,用于比较光正交频分复用符号生成模块 601生成的 m组光 正交频分复用符号的峰均功率比;
扰码模块 603, 用于根据比较模块 602的比较结果, 选用产生最小峰均 功率比的随机序列将所需传输的信息码元进行扰码, 以使所述光正交频分 复用符号生成模块 601生成光正交频分复用符号;
接收设备 1102包括还原模块 801、译码模块 802和去扰码模块 803,其中: 还原模块 801, 用于将接收的光正交频分复用符号还原成二进制序列; 译码模块 802, 用于根据还原模块 801还原所得二进制序列, 采用基于 最大似然准则的维特比译码确定发送端发送的信号序列, 发送端发送的信 号序列包含扰码和信息码元;
去扰码模块 803, 用于去除发送端发送的信号序列中包含的扰码, 得到 信息码元。
需要说明的是, 上述系统各模块 /单元之间的信息交互、 执行过程等内 容, 由于与本发明方法实施例基于同一构思, 其带来的技术效果与本发明 方法实施例相同, 具体内容可参见本发明方法实施例中的叙述, 此处不再 赘述。
以上对本发明实施例提供的一种降低光正交频分复用系统峰均功率比 的方法、 设备和系统进行了详细介绍, 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

权利要求
1、 一种降低光正交频分复用系统峰均功率比的方法, 其特征在于, 包 括:
根据扰码器产生的 m组长度相同的随机序列生成 m组光正交频分复用 符号, m为大于 1的自然数, 所述 m组光正交频分复用符号携带相同信息码 元;
比较所述 m组光正交频分复用符号的峰均功率比;
选用产生最小峰均功率比的随机序列, 将所需传输的信息码元进行扰 码, 以生成光正交频分复用符号。
2、 如权利要求 1所述的方法, 其特征在于, 所述根据扰码器产生的 m组 长度相同的随机序列生成 m组光正交频分复用符号包括:
所述扰码器生成 m组长度相同的随机序列;
将所述 m组长度相同的随机序列与所述相同信息码元混合得到 m组数 字序列;
将所述 m组数字序列映射成 m组映射序列;
将所述 m组映射序列依次经过串并变换、 星座映射、 反傅里叶变换、 加 载循环前缀和并串变换后得到所述 m组光正交频分复用符号。
3、 如权利要求 2所述的方法, 其特征在于, 所述将所述 m组数字序列映 射成 m组映射序列具体为:
将所述 m组数字序列中的每一组数字序列通过卷积编码变换成所述 m 组映射序列。
4、 如权利要求 1所述的方法, 其特征在于, 所述选用产生最小峰均功 率比的随机序列将所需传输的信息码元进行扰码以生成光正交频分复用符 号包括:
所述扰码器接收反馈的峰均功率比最小的光正交频分复用符号; 由所述峰均功率比最小的光正交频分复用符号确定对所需传输的信息 码元进行扰码时使用的随机序列;
将所述产生最小峰均功率比的随机序列与所述信息码元混合成数字序 列; 将所述混合后所得数字序列映射成映射序列;
将所述映射序列依次经过串并转换、 星座映射、 反傅里叶变换、 加载 循环前缀和并串变换后得到所述光正交频分复用符号。
5、 一种降低光正交频分复用系统峰均功率比的方法, 其特征在于, 包 括:
将接收的光正交频分复用符号还原成二进制序列;
根据所述二进制序列, 采用基于最大似然准则的维特比译码确定发送 端发送的信号序列, 所述发送端发送的信号序列包含扰码和信息码元; 去除所述发送端发送的信号序列中包含的扰码, 得到所述信息码元。
6、 如权利要求 5所述的方法, 其特征在于, 所述将接收的光正交频分 复用符号还原成二进制序列具体为:
将所述光正交频分复用符号依次经过串并变换、 去循环前缀、 傅里叶 变换、 星座解调和并串变换。
7、 如权利要求 5所述的方法, 其特征在于, 所述采用基于最大似然准 则的维特比译码确定发送端发送的信号序列包括:
将所述由光正交频分复用符号还原所得的二进制序列与发送端所有可 能发送的信号序列比较;
由比较结果得到汉明距离最小的信号序列确定为发送端发送的信号序 列。
8、 一种降低光正交频分复用系统峰均功率比的设备, 其特征在于, 包 括光正交频分复用符号生成模块、 比较模块和扰码模块;
所述光正交频分复用符号生成模块,用于根据所述扰码模块产生的 m组 长度相同的随机序列生成 m组光正交频分复用符号, m为大于 1的自然数, 所述 m组光正交频分复用符号携带相同信息码元;
所述比较模块,用于比较所述光正交频分复用符号生成模块生成的 m组 光正交频分复用符号的峰均功率比;
所述扰码模块, 用于根据所述比较模块的比较结果, 选用产生最小峰 均功率比的随机序列将所需传输的信息码元进行扰码, 以使所述光正交频 分复用符号生成模块生成光正交频分复用符号。
9、 如权利要求 8所述的设备, 其特征在于, 所述扰码模块还用于生成 m 组长度相同的随机序列;
所述光正交频分复用符号生成模块还包括混合单元、 映射单元、 串并 变换单元、 星座映射单元、 反傅里叶变换单元、 前缀加载单元和并串变换 单元;
所述混合单元,用于将所述 m组长度相同的随机序列与所述相同信息码 元混合得到 m组数字序列;
所述映射单元, 用于将所述混合单元混合所得 m组数字序列映射成 m组 映射序列;
所述串并变换单元、 星座映射单元、 反傅里叶变换单元、 前缀加载单 并变换、 星座映射、 反傅里叶变换、 加载循环前缀和并串变换后得到所述 m 组光正交频分复用符号。
10、 一种降低光正交频分复用系统峰均功率比的设备, 其特征在于, 包括还原模块、 译码模块和去扰码模块;
所述还原模块, 用于将接收的光正交频分复用符号还原成二进制序列; 所述译码模块, 用于根据所述二进制序列, 采用基于最大似然准则的 维特比译码确定发送端发送的信号序列, 所述发送端发送的信号序列包含 扰码和信息码元;
所述去扰码模块, 用于去除所述发送端发送的信号序列中包含的扰码 得到所述信息码元。
11、 如权利要求 10所述的设备, 其特征在于, 所述还原模块包括串并 变换单元、 去循环前缀单元、 傅里叶变换单元、 星座解调单元和并串变换 单元;
所述串并变换单元、 去循环前缀单元、 傅里叶变换单元、 星座解调单 元和并串变换单元依次用于对所述光正交频分复用符号进行串并变换、 去 循环前缀、 傅里叶变换、 星座解调和并串变换。
12、 如权利要求 10所述的设备, 其特征在于, 所述译码模块包括比较 单元和确定单元; 所述比较单元, 用于将所述由光正交频分复用符号还原所得的二进制 序列与发送端所有可能发送的信号序列比较;
所述确定单元, 用于由所述比较单元比较结果得到汉明距离最小的信 号序列确定为发送端发送的信号序列。
13、 一种降低光正交频分复用系统峰均功率比的系统, 其特征在于, 所述系统包括发送设备和接收设备;
所述发送设备包括光正交频分复用符号生成模块、 比较模块和扰码模 块;
所述光正交频分复用符号生成模块,用于根据所述扰码模块产生的 m组 长度相同的随机序列生成 m组光正交频分复用符号, m为大于 1的自然数, 所述 m组光正交频分复用符号携带相同信息码元;
所述比较模块,用于比较所述光正交频分复用符号生成模块生成的 m组 光正交频分复用符号的峰均功率比;
所述扰码模块, 用于根据所述比较模块的比较结果, 选用产生最小峰 均功率比的随机序列, 将所需传输的信息码元进行扰码, 以使所述光正交 频分复用符号生成模块生成光正交频分复用符号;
所述接收设备包括还原模块、 译码模块和去扰码模块;
所述还原模块, 用于将接收的光正交频分复用符号还原成二进制序列; 所述译码模块, 用于根据所述二进制序列, 采用基于最大似然准则的 维特比译码确定发送端发送的信号序列, 所述发送设备发送的信号序列包 含扰码和信息码元;
所述去扰码模块, 用于去除所述发送设备发送的信号序列中包含的扰 码得到所述信息码元。
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