Background technology
In communication system, because the time domain disperse characteristic of channel, receiver receives the multipath fading signal of a plurality of different delay that send signal simultaneously, the multi-path influence of channel will cause intersymbol interference, and receiver must take certain technology to overcome multipath fading to recover original transmission signal.
In second generation mobile communication system, adopt viterbi equalizer to overcome multipath fading, its complexity is the exponential function of channel memory span, therefore is not suitable for wide-band communication system.In 3-G (Generation Three mobile communication system) WCDMA/HSDPA, adopt the distortion of time domain linear equalizer compensate for channel, the shortcoming of this technology is that the complexity of its realization is the cube of channel memory span, and its performance is subjected to the influence of residual intersymbol interference.The multi-carrier transmission technology can overcome the multipath fading of channel effectively, and it is divided into the subcarrier of some quadratures with whole bandwidth, makes symbol duration elongated, and each sub-carrier channels is approximately flat decline, and receiver only need be done the single-point equilibrium of low complex degree.Can isolate the influence of channel multi-path decline effectively based on the single carrier/multi-carrier transmission technology of Cyclic Prefix (CP), thereby can utilize the frequency domain equalization of low complex degree to carry out channel equalization.
As shown in Figure 1 be the equalizing receiver of existing single carrier transmitting system, this device comprises successively and to connect: antenna, remove cyclic prefix module, serial/parallel modular converter, FFT (fast fourier transform) module, subchannel balance module, IFFT (contrary Fourier Tranform) module, parallel/serial modular converter, separate mapping block, channel decoding module, information bit module.
Shown in Figure 2 is the equalizing receiver of existing multicarrier transmission systems, and this device comprises successively and to connect: Receiver Module, serial/parallel modular converter, multichannel time-domain filtering module, the first Fourier Tranform module, multichannel frequency domain equalization module, parallel/serial modular converter, separate mapping de-interleaving block, channel decoding module, information bit module.Wherein said each road frequency domain equalization module includes connection successively: remove cyclic prefix module, Fourier Tranform module, subchannel balance module, contrary Fourier Tranform module.
The shortcoming of tradition single carrier/multicarrier transmission systems equilibrium acceptance method be must be complementary with its transmission manner, the complexity height.The equilibrium of single carrier must be carried out on the virtual subnet carrier wave of frequency domain, the equilibrium of multicarrier is balanced on the subcarrier after the multicarrier demodulation, all need to carry out frequency domain equalization on each subcarrier, fast fourier transform (FFT) number that needs is a sub-carrier number purpose twice.When number of sub carrier wave was very big, the complexity height of system was unfavorable for actual system implementation.Because the equalization methods difference of traditional single carrier, multi-carrier transmission, for the up employing single carrier transmission of mobile communication system behind the third generation, during descending employing multi-carrier transmission, system need adopt different balance policies at up-downgoing, is unfavorable for the realization of system.
Summary of the invention
Technical problem to be solved by this invention provides a kind of equalizing receiver that can be applied to single carrier transmission and multi-carrier transmission simultaneously, this has expanded multi-carrier equalizing must carry out balanced restriction at the frequency domain subchannel, directly carry out frequency domain equalization at the sampled signal of received signal, simplified the complexity of balanced reception, make the data of rear end recover simpler, improved the receiver application flexibility.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is:
A kind of broadband single-carrier/multi-carrier equalizing receiver is provided, comprises: Receiver Module, synchronously and channel estimation module, serial/parallel modular converter, it is characterized in that, also comprise:
The frequency domain equalization module, its with serial/parallel modular converter, be connected with the output of channel estimation module synchronously, it utilizes the estimated channel fading coefficients that sampled signal is carried out frequency domain equalization;
Handover module, its output with the frequency domain equalization module is connected, and is used to carry out the switching that single carrier or multicarrier demultiplexing are separated frame;
Frame module is recovered/separated to single-carrier signal, and its output with handover module 8 is connected, and is used to recover the symbol of single carrier transmission;
Multi-carrier signal recovers/separates frame module, and its output with handover module 8 is connected, and is used to recover the symbol of multi-carrier transmission.
Further, the present invention also provides a kind of broadband single-carrier/multi-carrier equalizing method of reseptance, comprising: radio frequency receiving step, synchronously and channel estimation steps, serial/parallel switch process, and:
The frequency domain equalization step utilizes the estimated channel fading coefficients that sampled signal is carried out frequency domain equalization;
Switch step carries out the switching that single carrier or multicarrier demultiplexing are separated frame;
The frame step is recovered/separated to single-carrier signal, is used to recover the symbol of single carrier transmission;
Multi-carrier signal recovers/separates the frame step, is used to recover the symbol of multi-carrier transmission.
Broadband single-carrier/multi-carrier equalizing receiver of the present invention can obtain extensive use at wireless broadband communication and moving communicating field, especially in the 4th third-generation mobile communication field vast potential for future development will be arranged.Be mainly used in the reception broadband wireless signal, utilize same receiver can receive the single carrier transmission signal, also can receive multi-carrier transmission signal.Can adapt to traditional single carrier and multicarrier more communication scenes that can not adapt to fully, for communication system has increased a new design freedom.Broadband single-carrier/multi-carrier equalizing receiver will be united based on the single carrier of Cyclic Prefix and the balanced reception technique of multicarrier in theory, and both are the former special applications the back.
Embodiment
Shown in Fig. 3,4, broadband single-carrier/multi-carrier equalizing receiver of the present invention comprises:
Receiver Module 1, it receives the signal in the wireless channel, is converted to base band and handles.Through reception antenna and radio frequency processing module, receiver output baseband signal.
Synchronously and channel estimation module 2, be connected, be used to finish the Time and Frequency Synchronization and the channel fading coefficient estimation of received signal with the output of Receiver Module.
Remove Cyclic Prefix (CP) module 3, be connected, be used to delete the signal cycle prefix that is subjected to intersymbol interference, eliminate inter-block-interference, isolate the influence of channel delay expansion, be beneficial to the frequency domain equalization of receiver with the output of Receiver Module.
Serial/parallel modular converter 4 is responsible for the serial data sequence of input is transformed into parallel dateout sequence.
The frequency domain equalization module, its with serial/parallel modular converter, be connected with the output of channel estimation module synchronously, it utilizes the estimated channel fading coefficients that sampled signal is carried out frequency domain equalization;
Handover module 8, its output with the frequency domain equalization module is connected, and is used to carry out the switching that single carrier or multicarrier demultiplexing are separated frame, so that further handle.
Frame module is recovered/separated to single-carrier signal, and its output with handover module 8 is connected, and is used to recover the symbol of single carrier transmission;
Multi-carrier signal recovers/separates frame module, and its output with handover module 8 is connected, and is used to recover the symbol of multi-carrier transmission;
Wherein, described frequency domain equalization module comprises connection successively:
FFT conversion module 5, it is connected with the output of serial/parallel modular converter, is used for the received signal data block of certain-length is transformed to frequency domain, so that eliminate the influence of channel to this data block in frequency domain equalization;
Single-point balance module 6, its output with the FFT conversion module is connected, and is used at frequency domain channel impairments being carried out the compensation of phase place and amplitude;
IFFT conversion module 7, its output with the single-point balance module is connected, and the frequency domain subband signal that is used for passing through frequency domain equalization returns to time domain, so that further handle.
Described single-carrier signal is recovered/is separated frame module and comprises successively and to connect:
Parallel/serial modular converter 10, it is connected with the output of handover module, is used for the parallel data sequence transformation of input is become the dateout sequence of serial.
Separate mapping de-interleaving block 11, be used for the data sequence of input being separated and be mapped to the corresponding digital sequence, and carry out the bit deinterleaving according to the sign map rule of transmitting terminal.If the channel decoding that is about to carry out is then exported the hard information Serial No. of forming by 0,1 based on the hard decision input information.Else symbol is separated mapping and will be provided accordingly based on the soft message digit sequence of counting bit quantization.
Channel decoding module 12 is used to carry out corresponding channel decoding algorithm.Through the channel decoding module, the coded-bit of input becomes information bit data sequence according to sequence transformation.
Information bit module 13 is used for that receiver is recovered information bit data sequence and passes to the upper application module processing.
Described multi-carrier signal recovers/separates frame module and comprises successively and to connect:
Multichannel time-domain filtering module 9, its output with the frequency domain equalization module is connected, and is used for multi-carrier transmission signal is carried out sub-band filter.
FFT conversion module 5, it carries out fast fourier transform to filtered signal.
Parallel/serial modular converter 10, it is used for the parallel data sequence transformation of input is become the dateout sequence of serial.
Separate mapping de-interleaving block 11, be used for the data sequence of input being separated and be mapped to the corresponding digital sequence, and carry out the bit deinterleaving according to the sign map rule of transmitting terminal.If the channel decoding that is about to carry out is then exported the hard information Serial No. of forming by 0,1 based on the hard decision input information.Else symbol is separated mapping and will be provided accordingly based on the soft message digit sequence of counting bit quantization.
Channel decoding module 12 is used to carry out corresponding channel decoding algorithm.Through the channel decoding module, the coded-bit of input becomes information bit data sequence according to sequence transformation.
Information bit module 13 is used for that receiver is recovered information bit data sequence and passes to the upper application module processing.
Adopt the present invention, receiver both can receive the single carrier transmission signal, also can receive multi-carrier transmission signal, employing is based on the unified equilibrium of frequency domain equalization reception carrying out to received signal of signal sampling, then according to transmission be that single carrier or multi-carrier transmission signal switch, obtain the information transmitted bit sequence with the signal demultiplexing/separate the signal of frame method after equilibrium of correspondence.
Further, broadband single-carrier of the present invention/multi-carrier equalizing method of reseptance comprises:
The radio frequency receiving step, it receives the signal in the wireless channel, is converted to base band and handles.Through reception antenna and radio frequency processing module, receiver output baseband signal.
Synchronously and channel estimation steps, be used to finish the Time and Frequency Synchronization and the channel fading coefficient estimation of received signal.
Remove Cyclic Prefix (CP) step, be used to delete the signal cycle prefix that is subjected to intersymbol interference, eliminate inter-block-interference, isolate the influence of channel delay expansion, be beneficial to the frequency domain equalization of receiver.
Serial/parallel switch process is responsible for the serial data sequence of input is transformed into parallel dateout sequence.
The frequency domain equalization step utilizes the estimated channel fading coefficients that sampled signal is carried out frequency domain equalization;
Switch step is used to carry out the switching that single carrier or multicarrier demultiplexing are separated frame, so that further handle.
The frame step is recovered/separated to single-carrier signal, is used to recover the symbol of single carrier transmission;
Multi-carrier signal recovers/separates the frame step, is used to recover the symbol of multi-carrier transmission;
Wherein, described frequency domain equalization step comprises:
The FFT shift step is used for the received signal data block of certain-length is transformed to frequency domain, so that eliminate the influence of channel to this data block in frequency domain equalization;
The single-point equalization step is used at frequency domain channel impairments being carried out the compensation of phase place and amplitude;
The IFFT shift step, its output with the single-point balance module is connected, and the frequency domain subband signal that is used for passing through frequency domain equalization returns to time domain, so that further handle.
Described single-carrier signal is recovered/is separated the frame step and comprises:
Parallel/serial switch process, the parallel data sequence transformation that is used for importing becomes the dateout sequence of serial.
Separate mapping deinterleaving step, be used for the data sequence of input being separated and be mapped to the corresponding digital sequence, and carry out the bit deinterleaving according to the sign map rule of transmitting terminal.If the channel decoding that is about to carry out is then exported the hard information Serial No. of forming by 0,1 based on the hard decision input information.Else symbol is separated mapping and will be provided accordingly based on the soft message digit sequence of counting bit quantization.
The channel decoding step is used to carry out corresponding channel decoding algorithm.Through the channel decoding module, the coded-bit of input becomes information bit data sequence according to sequence transformation.
The information bit step is used for that receiver is recovered information bit data sequence and passes to the upper application module processing.
Described multi-carrier signal recovers/separates the frame step and comprises:
Multichannel time-domain filtering step is used for multi-carrier transmission signal is carried out sub-band filter.
The FFT shift step, it carries out fast fourier transform to filtered signal.
Parallel/serial switch process, the parallel data sequence transformation that is used for importing becomes the dateout sequence of serial.
Separate mapping deinterleaving step, be used for the data sequence of input being separated and be mapped to the corresponding digital sequence, and carry out the bit deinterleaving according to the sign map rule of transmitting terminal.If the channel decoding that is about to carry out is then exported the hard information Serial No. of forming by 0,1 based on the hard decision input information.Else symbol is separated mapping and will be provided accordingly based on the soft message digit sequence of counting bit quantization.
The channel decoding step is used to carry out corresponding channel decoding algorithm.Through the channel decoding module, the coded-bit of input becomes information bit data sequence according to sequence transformation.
The information bit step is used for that receiver is recovered information bit data sequence and passes to the upper application module processing.
For reception transmission system shown in Figure 3, the block length that can suppose transmission is M, and the length of Cyclic Prefix (CP) is greater than the maximum delay expansion of channel, and the baseband sampling signal phasor behind the receiving terminal removal this moment CP can be expressed as:
y=Hx+z (1)
Wherein x is the baseband sampling vector of the transmission of M * 1 dimension; Z is a zero-mean white Gauss noise vector, and satisfies
H is a channel matrix, is a circular matrix, can be expressed as following form:
H=[h (0), h (1) ...., h (L-1)]
TFor transmitting antenna to the channel response vector between the reception antenna, L is the maximum distinguishable footpath of channel.Because H is a circular matrix, can carry out diagonalization, then H can be expressed as:
H=F
HΛF (3)
Wherein, F represents normalization DFT transformation matrix, Λ=diag{H (0), and H (1) ..., H (M-1) }, H (k) is the DFT conversion of h, that is:
[H(0),H(1),..,H(M-1)]
T=sqrt(M)Fh (4)
Under the known situation of channel impulse response and noise statistics, the least mean-square error (MMSE) that is obtained the sampled signal vector that base band sends by baseband receiving signals sample vector y is estimated as:
Therefore, being estimated as of the sampled signal vector x of base band transmission:
The method of estimation that following formula provides needs a DFT and an IDFT computing, and the frequency domain response of calculating channel needs a DFT computing simultaneously.The complexity of receiver and the number of sub carrier wave of system information transmissions are irrelevant, promptly can recover the baseband sampling signal of transmission by frequency domain equalization.
Estimation by the baseband sampling signal phasor x that sends
Carry out single carrier respectively or the multicarrier demultiplexing is separated the raw information that frame can recover single carrier or multi-carrier transmission.