CN203872200U

CN203872200U - Orthogonal frequency division multiplexing code division multiple access communication system signal reception device

Info

Publication number: CN203872200U
Application number: CN201420092085.6U
Authority: CN
Inventors: 杨童
Original assignee: China Academy of Space Technology CAST
Current assignee: China Academy of Space Technology CAST
Priority date: 2014-02-28
Filing date: 2014-02-28
Publication date: 2014-10-08
Anticipated expiration: 2024-02-28

Abstract

Orthogonal frequency division multiplexing code division multiple access communication system signal receiving device, the first-stage correlation detection and despreading unit in the device is formed by connecting a signal multiplier and a correlator; the second-stage integral detection and demodulation unit includes N Each sub-channel is connected by a signal multiplier and an integrator; the RF receiving front-end module is connected to the ADC and the down-conversion module, and the ADC and the down-conversion module are connected to the signal multiplier of the first-stage correlation detection despreading unit, The correlator is connected to the sub-carrier signal replication module; the sub-carrier signal replication module has parallel N-way output terminals, each output terminal is connected to a signal multiplier of the second-stage integral detection demodulation unit, and the integrator is connected to the data stream parallel-serial exchange module, The data stream parallel-to-serial conversion module is sequentially connected to the data symbol demultiplexing module and the data symbol parameter estimation module.

Description

Orthogonal frequency division multiplexing code division multiple access communication system signal receiving device

技术领域technical field

本实用新型属于移动通信技术领域，涉及一种实现正交频分复用码分多址通信系统的接收装置。The utility model belongs to the technical field of mobile communication, and relates to a receiving device for realizing an orthogonal frequency division multiplexing code division multiple access communication system.

背景技术Background technique

码分复用/码分多址通信体制普遍具有很高的信道带宽，但是抗多径干扰性能较差，实际系统中通常采用降低码速率的方法或利用窄带传输，例如全球星系统中使用的话音数据传输是一种仅能支持到10kbps量级的窄带扩频通信。Code division multiplexing/code division multiple access communication systems generally have very high channel bandwidth, but the anti-multipath interference performance is poor. In actual systems, the method of reducing the code rate or using narrow-band transmission is usually used, such as the one used in the global star system. Voice data transmission is a narrowband spread spectrum communication that can only support 10kbps order of magnitude.

正交频分复用/正交频分多址通信体制已在地面移动通信系统中广泛使用，被誉为是未来下一代无线通信（4G）的潮流技术，该技术本身就是为了解决多径干扰而设计的，通过多载波传输可以支持更高的数据率，100Mbps甚至更高，此外，由于采用了正交多载波传输技术，其频谱可以重叠，大大提升了频率资源的有效利用率，这在卫星通信等频谱资源受限的通信条件下显得尤为宝贵。Orthogonal frequency division multiplexing/orthogonal frequency division multiple access communication system has been widely used in ground mobile communication systems, and is known as the trend technology of the next generation of wireless communication (4G) in the future. This technology itself is to solve multipath interference It is designed to support higher data rates through multi-carrier transmission, 100Mbps or even higher. In addition, due to the use of orthogonal multi-carrier transmission technology, its spectrum can overlap, which greatly improves the effective utilization of frequency resources. It is especially valuable under communication conditions with limited spectrum resources such as satellite communication.

目前，国内外相关研究领域普遍通过二选一的方式将正交频分与码分两种体制相结合，即在系统发射装置里设置选择开关及处理器模块，通过开关切换来选择传输正交频分或码分信号，通过处理器模块对传输信号进行相应的编码、调制、复用等操作，且在系统接收装置里也要设置相同的模块；这种系统设计十分复杂，成本较高，而且开关切换一次只能选择单一种传输模式，不能真正实现将正交频分与码分两种体制相结合即混合传输互相兼容的设计思想，这种二选一的方式难以适应当前及未来通信系统兼容性及扩展性的发展需要。At present, related research fields at home and abroad generally combine the two systems of orthogonal frequency division and code division by choosing one of the two systems, that is, a selection switch and a processor module are set in the system transmitter, and the transmission orthogonality is selected by switching the switch. For frequency division or code division signals, the corresponding encoding, modulation, multiplexing and other operations are performed on the transmission signal through the processor module, and the same module must be set in the system receiving device; this kind of system design is very complicated and the cost is high. Moreover, only a single transmission mode can be selected at a switchover, and the design idea of combining the two systems of orthogonal frequency division and code division, that is, hybrid transmission and mutual compatibility, cannot be truly realized. This method of choosing one of the two is difficult to adapt to current and future communications. The development needs of system compatibility and scalability.

发明内容Contents of the invention

本发明的技术解决问题是：克服现有技术不足，提供了一种用于实现正交频分复用码分多址通信系统的接收装置。采用本实用新型能够提高信号的抗干扰性能，拓展了通信体制相互兼容性能。The technical solution problem of the present invention is: to overcome the deficiencies of the prior art, and provide a receiving device for realizing the Orthogonal Frequency Division Multiplexing Code Division Multiple Access communication system. The utility model can improve the anti-interference performance of the signal and expand the mutual compatibility performance of the communication system.

本发明的技术解决方案是：正交频分复用码分多址通信系统信号接收装置，包括射频接收前端模块、ADC与下变频模块、第一级相关检测解扩单元、副载波信号复制模块、第二级积分检测解调单元、数据流并串变换模块，数据符号解复用模块，数据符号参数估计模块；The technical solution of the present invention is: OFDM code division multiple access communication system signal receiving device, including radio frequency receiving front-end module, ADC and down-conversion module, first-stage correlation detection and despreading unit, subcarrier signal replication module , The second-stage integral detection and demodulation unit, the data stream parallel-to-serial conversion module, the data symbol demultiplexing module, and the data symbol parameter estimation module;

所述的第一级相关检测解扩单元由一个信号乘法器和一个相关器连接而成；第二级积分检测解调单元包括N路子信道，每路子信道由一个信号乘法器和一个积分器连接而成；射频接收前端模块连接ADC与下变频模块，ADC与下变频模块与第一级相关检测解扩单元的信号乘法器连接，相关器连接副载波信号复制模块；副载波信号复制模块具有并行N路输出端，每个输出端连接第二级积分检测解调单元的一个信号乘法器，积分器连接数据流并串交换模块，数据流并串变换模块依次连接数据符号解复用模块和数据符号参数估计模块；The first-stage correlation detection and despreading unit is formed by connecting a signal multiplier and a correlator; the second-stage integration detection and demodulation unit includes N sub-channels, and each sub-channel is connected by a signal multiplier and an integrator The RF receiving front-end module is connected to the ADC and the down-conversion module, the ADC and the down-conversion module are connected to the signal multiplier of the first-stage correlation detection despreading unit, and the correlator is connected to the sub-carrier signal replication module; the sub-carrier signal replication module has a parallel N-way output terminals, each output terminal is connected to a signal multiplier of the second-stage integral detection demodulation unit, the integrator is connected to the data stream parallel-serial switching module, and the data stream parallel-serial conversion module is sequentially connected to the data symbol demultiplexing module and the data Symbolic parameter estimation module;

ADC与下变频模块将射频接收前端模块接收的射频信号转换成码分多址副载波信号，第一级相关检测解扩单元将码分多址副载波信号进行正交解调后积分处理得到正交频分复用副载波信号；副载波信号复制模块将正交频分复用副载波信号复制成N路，第二级积分检测解调单元将每一路的正交频分复用副载波信号进行相关解扩，得到N路原始数据符号；数据流并串变换模块将N路原始数据符号从并行传输变换为串行传输，由数据符号解复用模块形成多用户的原始数据符号；数据符号参数估计模块对多用户的原始数据符号进行精确参数估计与补偿均衡，最终获取原始数据符号的精估计值。The ADC and down-conversion module convert the RF signal received by the RF receiving front-end module into a code division multiple access subcarrier signal. OFDM sub-carrier signal; the sub-carrier signal duplication module replicates the OFDM sub-carrier signal into N channels, and the second-stage integral detection and demodulation unit converts the OFDM sub-carrier signal of each channel Correlation despreading is performed to obtain N channels of original data symbols; the data stream parallel-to-serial conversion module converts N channels of original data symbols from parallel transmission to serial transmission, and the data symbol demultiplexing module forms multi-user original data symbols; the data symbols The parameter estimation module performs accurate parameter estimation and compensation equalization on the original data symbols of multiple users, and finally obtains the fine estimated value of the original data symbols.

本发明与现有技术相比有益效果为：Compared with the prior art, the present invention has beneficial effects as follows:

（1）本实用新型采用能够同时接收正交频分与码分两种通信体制的混合信号，有效拓展了两种通信体制的相互兼容性，并且兼容了两种体制自身的优势。(1) The utility model adopts the mixed signal capable of receiving two communication systems of orthogonal frequency division and code division at the same time, which effectively expands the mutual compatibility of the two communication systems, and is compatible with the advantages of the two systems themselves.

（2）本实用新型在接收装置的功能模块中采用两级相关积分检测解扩解调组件单元（先解扩后解调），实现了码分多址信号的相关解扩，并对解扩出的正交频分复用信号实现了正交解调，从而有效获取并恢复出原始数据符号的粗估计值。(2) The utility model adopts a two-stage correlation integral detection despreading demodulation component unit (first despreading and then demodulation) in the functional module of the receiving device, and realizes the correlation despreading of the code division multiple access signal, and despreading Orthogonal demodulation is realized for the obtained OFDM signal, so that the rough estimation value of the original data symbol can be obtained and restored effectively.

（3）本实用新型在接收装置的功能模块中采用基于频域的数据符号参数估计模块，通过FFT变换域，仅用一次除法运算即可完成所有原始数据符号的参数估计，最终获取原始数据符号的精估计值，算法简便易操作，实时性好，便于实现。(3) The utility model adopts a data symbol parameter estimation module based on the frequency domain in the functional module of the receiving device. Through the FFT transform domain, the parameter estimation of all original data symbols can be completed with only one division operation, and finally the original data symbols can be obtained. The precise estimated value of , the algorithm is simple and easy to operate, has good real-time performance, and is easy to implement.

附图说明Description of drawings

图1为本实用新型功能模块示意图；Fig. 1 is the functional module schematic diagram of the present utility model;

图2为本实用新型解扩解调组件单元原理图；Fig. 2 is a schematic diagram of the despreading and demodulating component unit of the present invention;

图3为本实用新型数据符号参数估计模块结构图。Fig. 3 is a structural diagram of the data symbol parameter estimation module of the utility model.

具体实施方式Detailed ways

下面结合附图对本实用新型的结构进行说明。码分复用正交频分多址通信系统信号接收装置，如图1所示，包括射频接收前端模块、ADC与下变频模块、第一级相关检测解扩单元、副载波信号复制模块、第二级积分检测解调单元、数据流并串变换模块，数据符号解复用模块，数据符号参数估计模块；Below in conjunction with accompanying drawing, structure of the present utility model is described. The signal receiving device of the code division multiplexing orthogonal frequency division multiple access communication system, as shown in Fig. A secondary integral detection demodulation unit, a data stream parallel-to-serial conversion module, a data symbol demultiplexing module, and a data symbol parameter estimation module;

如图2所示，第一级相关检测解扩单元由一个信号乘法器和一个相关器连接而成；第二级积分检测解调单元包括N路子信道，每路子信道由一个信号乘法器和一个积分器连接而成；射频接收前端模块连接ADC与下变频模块，ADC与下变频模块与第一级相关检测解扩单元的信号乘法器连接，相关器连接副载波信号复制模块；副载波信号复制模块具有并行N路输出端，每个输出端连接第二级积分检测解调单元的一个信号乘法器，积分器连接数据流并串交换模块，数据流并串变换模块依次连接数据符号解复用模块和数据符号参数估计模块；As shown in Figure 2, the first-stage correlation detection and despreading unit is formed by connecting a signal multiplier and a correlator; the second-stage integral detection and demodulation unit includes N sub-channels, and each sub-channel consists of a signal multiplier and a The integrator is connected; the RF receiving front-end module is connected to the ADC and the down-conversion module, the ADC and the down-conversion module are connected to the signal multiplier of the first-stage correlation detection despreading unit, and the correlator is connected to the sub-carrier signal replication module; the sub-carrier signal replication The module has parallel N output terminals, each output terminal is connected to a signal multiplier of the second-stage integral detection demodulation unit, the integrator is connected to the data flow parallel-serial switching module, and the data flow parallel-serial conversion module is connected to the data symbol demultiplexing in turn module and data symbol parameter estimation module;

射频接收前端模块、ADC与下变频模块负责将完成射频接收信号（该信号可来自地面无线移动通信网络和/或卫星移动通信网络转发）的锁频/锁相接收，预选滤波，模数转换，下变频等操作。经过射频接收前端模块、ADC与下变频模块处理后，获得副载波信号。The RF receiving front-end module, ADC and down-conversion module are responsible for completing the frequency-locked/phase-locked reception, pre-selection filtering, analog-to-digital conversion, and Down conversion and other operations. After being processed by the RF receiving front-end module, ADC and down-conversion module, the subcarrier signal is obtained.

第一级相关检测解扩单元负责将码分多址副载波信号进行相关解扩，通过一组与发射装置中相同的伪随机扩频码组（Gold序列）实现，相关后的码分多址副载波信号变为正交频分复用副载波信号。The first-stage correlation detection and despreading unit is responsible for correlating and despreading the CDMA subcarrier signal, which is realized by a group of pseudo-random spreading code groups (Gold sequence) that are the same as those in the transmitting device, and the correlated CDMA The subcarrier signal becomes an OFDM subcarrier signal.

正交频分复用信号复制模块负责将获得的正交频分复用副载波信号（单路）复制成多路（N路），每一路作为一个子信道，第一路定义成第0子信道，第二路定义成第1子信道，第三路定义成第2子信道，以此类推，至第N路定义成第N-1子信道，每一路上均传输相同的正交频分复用副载波信号，将每一路的副载波信号送给第二级积分检测解调单元进行处理，一般N在64、128、256、512、1024等几个数值中取值。The OFDM signal replication module is responsible for duplicating the obtained OFDM subcarrier signal (single channel) into multiple channels (N channels), each channel is regarded as a sub-channel, and the first channel is defined as the 0th sub-channel channel, the second channel is defined as the first sub-channel, the third channel is defined as the second sub-channel, and so on, until the Nth channel is defined as the N-1th sub-channel, each channel transmits the same orthogonal frequency division The sub-carrier signals are multiplexed, and the sub-carrier signals of each channel are sent to the second-stage integral detection and demodulation unit for processing. Generally, N takes values from several values such as 64, 128, 256, 512, and 1024.

第二级积分检测解调单元负责将每一路的正交频分复用副载波信号进行正交解调，通过与发射装置中相同（点数相同，量级相同）的正交FFT操作实现，积分后每一路的正交频分复用信号变为原始数据符号，此时的原始数据符号具有粗估计值。The second-stage integral detection and demodulation unit is responsible for the orthogonal demodulation of the OFDM subcarrier signals of each channel, which is realized by the same orthogonal FFT operation (same number of points and same magnitude) as in the transmitting device, and the integral Afterwards, the OFDM signal of each channel becomes an original data symbol, and the original data symbol at this time has a rough estimated value.

数据流并串变换模块负责将具有粗估计值的并行原始数据符号从并行传输变换为串行传输。The data stream parallel-to-serial conversion module is responsible for converting the parallel raw data symbols with coarse estimated values from parallel transmission to serial transmission.

数据符号解复用模块负责具有粗估计值的串行原始数据符号的拆包、分解、重组等操作，形成多用户的原始数据符号。The data symbol demultiplexing module is responsible for operations such as unpacking, decomposing, and recombining serial original data symbols with rough estimated values to form multi-user original data symbols.

数据符号参数估计模块负责对多用户的具有粗估计值的原始数据符号进行精确参数估计与补偿均衡，最终获取原始数据符号的精估计值，完成多用户的数据符号的重建与恢复。The data symbol parameter estimation module is responsible for accurate parameter estimation and compensation and equalization of the original data symbols with rough estimated values of multiple users, and finally obtains the fine estimated values of the original data symbols, and completes the reconstruction and recovery of multi-user data symbols.

如图2所示，第一级相关检测解扩单元，输入端是由一路经过中频基带变换后的码分多址副载波信号构成的单一通道，采用一个由信号乘法器和相关检测器构成的正交解扩器，其中，信号乘法器负责将接收到的副载波信号与本地生成的伪随机码进行乘法运算，相关检测器负责对相乘后的输出信号进行相关运算，并将码分复用副载波信号中的与当前用户相对应的扩频码不相关的其它用户扩频码分复用信号作非相关清零。As shown in Figure 2, the first stage correlation detection despreading unit, the input end is a single channel composed of a code division multiple access subcarrier signal after intermediate frequency baseband conversion, and a signal multiplier and a correlation detector are used. Orthogonal despreader, wherein the signal multiplier is responsible for multiplying the received subcarrier signal and the locally generated pseudo-random code, and the correlation detector is responsible for performing correlation operation on the multiplied output signal, and dividing the code The non-correlation clearing is performed by using other user spreading code division multiplexing signals which are not related to the spreading code corresponding to the current user in the subcarrier signal.

本地生成的伪随机具有和发射装置相同的伪随机码排列规则，满足伪随机码正交解扩的要求。The locally generated pseudo-random code has the same pseudo-random code arrangement rule as that of the transmitting device, which meets the requirement of orthogonal despreading of the pseudo-random code.

对每一路的码分多址副载波信号D(t)，可用式[1]计算经正交解扩输出的正交频分复用副载波信号：For the CDMA subcarrier signal D(t) of each channel, formula [1] can be used to calculate the OFDM subcarrier signal output by orthogonal despreading:

$\begin{matrix} S S {((t t))}^{e e} = = &Integral; &Integral; D D. ((t t)) \times \times C C ((00)) dr dr \\ = = &Integral; &Integral; S S ((t t)) \times \times C C ((r r)) \times \times C C ((00)) dr dr \\ = = S S ((t t)) \end{matrix} - - - - - - [[11]]$

式[1]中，C(0)表示本地生成的伪随机码，C(r)表示当前接收用户相对应的扩频码。这里利用了Gold伪随机码尖锐的自相关特性，这种特性表现为两个码只有完全相同时才能达到相关极大，否则为极小（接近0），解析式如式[2]所示：In formula [1], C(0) represents the locally generated pseudo-random code, and C(r) represents the spreading code corresponding to the currently receiving user. Here, the sharp autocorrelation characteristic of the Gold pseudo-random code is used. This characteristic shows that the two codes can reach the maximum correlation only when they are exactly the same, otherwise they are extremely small (close to 0). The analytical formula is shown in formula [2]:

$&Integral; &Integral; C C ((00)) \times \times C C ((r r)) = = \{\begin{matrix} 11 & r r = = 00 \\ - - \frac{11}{L L} \approx \approx 00 & r r &NotEqual; &NotEqual; 00 \end{matrix} - - - - - - [[22]]$

式[2]中，当某一路的本地伪随机码和接收到的用户扩频码不相干时，式[2]将输出极小值，通常L取511或1023，则该值→0，即将码分多址副载波信号中的与当前用户相对应的扩频码不相关的其它用户扩频码分复用信号作非相关清零，提高了通信系统的抗干扰性能；当某一路的本地伪随机码和接收到的用户扩频码相干时，式[2]将输出1，并将相应的解扩出的正交频分复用副载波信号送出，满足了多用户正交解扩的要求。In formula [2], when the local pseudo-random code of a certain channel is irrelevant to the received user spreading code, formula [2] will output a minimum value, usually L is 511 or 1023, then the value → 0, that is, In the CDMA subcarrier signal, the spreading code division multiplexing signals of other users that are not related to the spreading code corresponding to the current user are used for non-correlation clearing, which improves the anti-interference performance of the communication system; when a local When the pseudo-random code is coherent with the received user spreading code, the formula [2] will output 1, and send out the corresponding despread OFDM subcarrier signal, which satisfies the requirement of multi-user orthogonal despreading Require.

第二级积分检测解调单元，输入端是由N路传输相同的（经过复制的）正交频分复用副载波信号构成的子信道，每一路均采用一个由信号乘法器和积分检测器构成的正交解调器，其中，信号乘法器负责将每一路的接收到的副载波信号与本地生成的相干载波进行乘法运算，积分检测器负责对相乘后的输出信号进行积分运算，并将正交频分复用副载波信号中的与当前子信道相对应的子载波频率线性无关的干扰信号积分清零。The second-stage integral detection demodulation unit, the input end is a sub-channel composed of N channels transmitting the same (replicated) OFDM subcarrier signal, and each channel adopts a signal multiplier and an integral detector The quadrature demodulator constituted, wherein, the signal multiplier is responsible for multiplying the received subcarrier signal of each channel with the locally generated coherent carrier, and the integral detector is responsible for integrating the multiplied output signal, and The integral of the interference signal that is linearly independent of the frequency of the sub-carrier corresponding to the current sub-channel in the OFDM sub-carrier signal is cleared.

每一路上的积分检测器均具有相同的结构，积分周期均相同；每一路上的信号乘法器均具有相同的结构，每一路上的本地生成的相干载波不同，且具有和发射装置相同的相干载波排列规则，满足多载波正交性的要求。The integration detectors on each path have the same structure, and the integration period is the same; the signal multipliers on each path have the same structure, and the locally generated coherent carriers on each path are different and have the same coherence as the transmitting device. Carrier arrangement rules meet the requirements of multi-carrier orthogonality.

设每一路的正交频分多址副载波信号（经过副载波信号复制模块复制后）为S(t)，则正交解调输出的具有粗估计值的原始数据符号P_n，可用式[3]计算：Let the OFDMA subcarrier signal of each channel (after being copied by the subcarrier signal copy module) be S(t), then the original data symbol P _n with rough estimated value output by quadrature demodulation can be expressed as [ 3] Calculate:

$\begin{matrix} {P P}_{n no}^{e e} = = &Integral; &Integral; S S ((t t)) \times \times exp exp ((- - j j 22 π π {f f}_{n no} t t)) dt dt \\ = = &Integral; &Integral; {Σ Σ}_{k k = = 00}^{N N - - 11} {d d}_{k k} \times \times exp exp ((j j 22 π π {f f}_{k k} t t)) \times \times exp exp ((- - j j 22 π π {f f}_{n no} t t)) dt dt - - - - - - [[33]] \\ = = {P P}_{n no} \end{matrix}$

式[3]中，多子载波f₀，f₁，f₂，…，f_N-1分别用来和每一路上正交频分复用副载波信号进行解调，d_k为运算过程中的变量。这里利用了多载波的正交性，这种正交性表现为载波之间可以互相交叠而又互不干扰，解析式如式[4]所示：In formula [3], the multi-subcarriers f ₀ , f ₁ , f ₂ ,..., f _N-1 are used to demodulate the OFDM subcarrier signals on each channel respectively, and d _k is the Variables. The orthogonality of multi-carriers is used here. This orthogonality shows that the carriers can overlap each other without interfering with each other. The analytical formula is shown in formula [4]:

$&Integral; &Integral; exp exp ((j j 22 π π {f f}_{k k} t t)) \times \times exp exp ((- - j j 22 π π {f f}_{n no} t t)) dt dt = = \{\begin{matrix} 11 & k k = = n no \\ 00 & k k &NotEqual; &NotEqual; 00 \end{matrix} - - - - - - [[44]]$

式[4]中，当某一路的本地相干载波和接收到的正交频分复用副载波信号的子载波不相同时，式[4]将输出0，即将正交频分复用副载波信号中的与当前子信道相对应的子载波频率线性无关的多址信号积分清零，进一步提高了通信系统的抗干扰性能；当某一路的本地相干载波和接收到的正交频分复用副载波信号的子载波相同时，式[4]将输出1，并将具有粗估计值的原始数据符号原送出，满足了多载波正交解调的要求。In formula [4], when the local coherent carrier of a certain channel is different from the subcarrier of the received OFDM subcarrier signal, formula [4] will output 0, that is, the OFDM subcarrier In the signal, the sub-carrier frequency corresponding to the current sub-channel is linearly independent of the multi-access signal integral, which further improves the anti-interference performance of the communication system; when the local coherent carrier of a certain channel and the received OFDM When the sub-carriers of the sub-carrier signals are the same, formula [4] will output 1, and send out the original data symbols with rough estimated values, which meets the requirements of multi-carrier orthogonal demodulation.

如图3所示，本实用新型所述的正交频分复用码分多址通信系统信号接收装置，其中数据符号参数估计模块负责对原始数据符号的参数估计。As shown in FIG. 3 , in the OFDM CDMA communication system signal receiving device described in the present invention, the data symbol parameter estimation module is responsible for parameter estimation of the original data symbols.

获得原始数据符号的粗估计值，同时也获得了导频符号的粗估计值，由于导频数据为已知信号，因此，可以直接获得这些导频符号通过传输信道造成的信道响应因子，如式[5]所示（为导频符号的信道响应值）：The rough estimate of the original data symbols and the rough estimate of the pilot symbols are also obtained. Since the pilot data is a known signal, the channel response factor caused by these pilot symbols passing through the transmission channel can be directly obtained, as shown in the formula As shown in [5] ( is the channel response value of the pilot symbol):

${P P}_{t t}^{e e} = = \frac{{P P}_{t t}^{r r}}{11 + + 00 j j} = = {P P}_{t t}^{r r} - - - - - - [[55]]$

由于估计算法是在FFT变换域之后的频域中进行的，因此只需要进行一次除法运算即可通过信道响应因子十分方便地获取原始数据符号的精确估计值，如式[6]所示：Since the estimation algorithm is carried out in the frequency domain after the FFT transform domain, only one division operation is required to obtain the accurate estimation value of the original data symbol very conveniently through the channel response factor, as shown in formula [6]:

${a a}_{k k} = = \frac{{a a}_{k k}^{e e}}{{P P}_{t t}^{e e}} - - - - - - [[66]]$

至此最终获得了原始数据符号的精估计值，完成了数据符号的重建与恢复工作。At this point, the precise estimated value of the original data symbol is finally obtained, and the reconstruction and restoration of the data symbol is completed.

本实用新型未详细说明部分属本领域技术人员公知常识。Parts not described in detail in the utility model belong to the common knowledge of those skilled in the art.

Claims

1. orthogonal frequency division multiplexing code division multiple access communication system signal receiving system, it is characterized in that: comprise receiver rf front-end module, ADC and down conversion module, first order coherent detection despread unit, subcarrier signal replication module, second level integrated detected demodulating unit, data flow parallel serial conversion module, data symbol demultiplexing module, data symbol parameter Estimation module;

Described first order coherent detection despread unit is formed by connecting by a signal multiplier and a correlator; Second level integrated detected demodulating unit comprises N subchannels, and every subchannels is formed by connecting by a signal multiplier and an integrator; Receiver rf front-end module connects ADC and down conversion module, and ADC is connected with the signal multiplier of first order coherent detection despread unit with down conversion module, correlator auxiliary connection carrier signal replication module; Subcarrier signal replication module has parallel N road output, each output connects a signal multiplier of second level integrated detected demodulating unit, integrator connection data flows and goes here and there Switching Module, and data flow parallel serial conversion module is connection data symbolic solution Multiplexing module and data symbol parameter Estimation module successively;

The radiofrequency signal that ADC and down conversion module receive receiver rf front-end module converts code division multiple access subcarrier signal to, and after first order coherent detection despread unit is carried out quadrature demodulation by code division multiple access subcarrier signal, integral processing obtains OFDM subcarrier signal; Subcarrier signal replication module is copied into N road by OFDM subcarrier signal, and second level integrated detected demodulating unit, by the despreading of being correlated with of the OFDM subcarrier signal on each road, obtains N road raw data symbols; Data flow parallel serial conversion module is transformed to serial transmission by N road raw data symbols from parallel transmission, is formed multi-user's raw data symbols by data symbol demultiplexing module; Data symbol parameter Estimation module is carried out accurate parameters estimation and compensating equalization to multi-user's raw data symbols, finally obtains the smart estimated value of raw data symbols.