CN1364009A - Transmitting and zero intermediate frequency receiving method and device in multi-carrier CDMA system based on polyphase decomposition - Google Patents

Abstract

Translated fromChinese

本发明提出了一种基于调制型滤波器组的多载波DS－CDMA系统发送与零中频接收方法及其多相分解的简化实现方法,其基本思路是:在接收端,将多载波DS－CDMA接收信号从射频或高中频下变频至基带,以使多个载波的中间一个载波的中心频率为零频率,运用最低的采样频率进行采样,以调制型滤波器组替代多载波数字滤波器,在分离多个载波接收信号并重建原各个载波上的发送信号的同时,利用多相分解简化接收机的实现结构,降低接收机的硬件实现复杂度。在发送端,同样以调制型滤波器组替代多载波数字滤波器,在将各载波预携带的信息并行经过调制型发送滤波器组的同时,利用多相分解简化发射机的实现结构,然后同时上变频到高中频或射频,本发明主要考虑如何在多载波DS－CDMA系统中充分发挥数字处理的能力,最大限度地节省了硬件资源,使系统的实现更加经济可靠。

The present invention proposes a multi-carrier DS-CDMA system transmission and zero-IF reception method based on a modulated filter bank and a simplified implementation method of polyphase decomposition thereof. The basic idea is: at the receiving end, the multi-carrier DS-CDMA The received signal is down-converted from radio frequency or high-frequency to baseband, so that the center frequency of a carrier in the middle of multiple carriers is zero frequency, and the lowest sampling frequency is used for sampling, and the multi-carrier digital filter is replaced by a modulated filter bank. While separating multiple carrier receiving signals and reconstructing the original sending signals on each carrier, polyphase decomposition is used to simplify the implementation structure of the receiver and reduce the hardware implementation complexity of the receiver. At the transmitting end, the multi-carrier digital filter is also replaced by a modulated filter bank. While the information pre-carried by each carrier passes through the modulated transmit filter bank in parallel, the implementation structure of the transmitter is simplified by using polyphase decomposition, and then simultaneously Up-conversion to high-medium frequency or radio frequency, the present invention mainly considers how to give full play to the ability of digital processing in the multi-carrier DS-CDMA system, save hardware resources to the greatest extent, and make the realization of the system more economical and reliable.

Description

Based on the multi-carrier CDMA system transmission of heterogeneous decomposition and the method for reseptance and the device of zero intermediate frequency

(1) technical field:

The invention belongs to CDMA (code division multiple access) field of cellular communication systems, relate in particular to based on the multi-carrier CDMA system transmission of heterogeneous decomposition and the method for reseptance and the device of zero intermediate frequency

(2) background technology:

The cdma cellular communication technology is simple with its frequency planning, power system capacity is big, ability of anti-multipath is strong, good communication quality, electromagnetic interference are little etc., and characteristics demonstrate huge development potentiality, are the mainstream technologys that comprises the future mobile communications of the third generation.Wherein, multicarrier DS-CDMA (direct sequence spread spectrum codes is divided multiple access) system has: support high speed data transfer, higher band efficiency, the outstanding advantage that can carry out effective frequency diversity and time diversity and suppress effectively to disturb etc.

Traditional multicarrier DS-CDMA receiver will adopt the high frequency analog matched filter of the high Q value that equates with the carrier wave number, to separate the signal that transmits on the different carrier frequency; Respectively the radiofrequency signal on each carrier wave is down-converted to base band again; Respectively the signal of each carrier wave is sampled at low frequency then.The tricks of the radio frequency analog circuit that such receiver needs equates with the number of carrier wave; And sample rate is minimum to be 2 times of signal bandwidth.The present invention only proposes to simulate receiving circuit downconverts to each carrier signal base band simultaneously from radio frequency or high intermediate frequency (high intermediate frequency is meant that the IF-FRE that is adopted is far above the modulation signal bandwidth) zero intermediate frequency method of reseptance with a cover.The zero intermediate frequency here is meant that the result of down-conversion makes that the centre frequency of the carrier wave in centre of a plurality of carrier waves is a zero frequency.Zero intermediate frequency reciver has following advantage: (1) does not need the high frequency matched filter of high Q value.But in zero intermediate frequency reciver, still use high frequency filter with the requirement of reduction, and prevent the mixing of the harmonic component of radiofrequency signal and local oscillator the down-conversion dynamic range.(2) owing to use zero intermediate frequency to receive, make low pass filter be easy to be integrated into chip internal, and use digital filter, given full play to the advantage of digital processing.(3) because zero intermediate frequency signals is a complex signal, therefore when follow-up digital processing, can reduce requirement most possibly, reduce hard-wired difficulty sample frequency.(4) consider from the angle of software radio, use zero intermediate frequency reciver will make digital processing part and RAKE receiver after A/D samples can be designed to Monolithic Receivers easily, only need a radio frequency handling device and A/D converter device.

(3) summary of the invention:

The objective of the invention is deficiency at existing multicarrier DS-CDMA system's transmission and reception technique, propose a kind ofly can give full play to the digital processing ability, reduce the transmission and the reception technique of the practicality of hardware size most possibly, make that the realization of system is more economical reliable.

The present invention proposes a kind of based on the multicarrier DS-CDMA system transmission of modulation type bank of filters and the simplification implementation method of zero intermediate frequency method of reseptance and heterogeneous decomposition thereof, its technical scheme is: at receiving terminal, multicarrier DS-CDMA received signal is downconverted to base band from radio frequency or high intermediate frequency, so that the centre frequency of the carrier wave in centre of a plurality of carrier waves is a zero frequency, use minimum sample frequency to sample, substitute the multi-carrier digital filter with the modulation type bank of filters, when separating a plurality of carrier wave received signals and rebuilding transmission signal on former each carrier wave, utilize the implementation structure of heterogeneous decomposition simplified receiver, reduce the hardware implementation complexity of receiver.At transmitting terminal, substitute the multi-carrier digital filter with the modulation type bank of filters equally, in the information parallel passes modulation type transmitting filter group that each carrier wave is carried in advance, utilize heterogeneous decomposition to simplify the implementation structure of transmitter, upconvert to high intermediate frequency or radio frequency then simultaneously.

Existing its implement device of accompanying drawings:

Multicarrier DS-CDMA system realizes may further comprise the steps based on the method for reseptance of the transmission of modulation type bank of filters and zero intermediate frequency and the simplification of heterogeneous decomposition thereof: at receiving terminal, multi-carrier signal is direct down-conversion-to base band from radio frequency or high intermediate frequency; Base band multicarrier received signal is sampled; Adopt digital filter to form the modulation type filter bank structure.At transmitting terminal, form modulation type transmitting filter group structure with digital filter; Information parallel passes modulation type transmitting filter group with each carrier wave carries in advance upconverts to radio frequency or high intermediate frequency then simultaneously.Modulation type bank of filters to transmitting-receiving two-end adopts the method for heterogeneous decomposition to simplify realization.Specifically be described respectively.1, based on the transmission of modulation type bank of filters and the method for reseptance of zero intermediate frequency

At receiving terminal, at first the received signal with multicarrier DS-CDMA downconverts to base band from radio frequency or high intermediate frequency, makes the centre frequency of the carrier wave in centre in a plurality of carrier waves be in the zero frequency position, filters out-of-band noise through low pass filter again.

Cdma2000-3x is an example with the configuration of cdma2000 three carrier waves, specifies zero intermediate frequency and receives implementation method.Fig. 1 (a) is the spectrum diagram of receiving terminal three carrier signals.The centre frequency of three carrier waves is respectively f₁, f₂, f₃, they satisfy

f₁+ f_Δ=f₂=f₃-f_Δ[formula 1]

F wherein_Δ=1.23MHz.After down-converted and low-pass filtering, obtain three carrier wave base-band signal spectrums shown in Fig. 1 (b), the centre frequency of its second carrier signal is zero.

The zero intermediate frequency baseband signal of three carrier waves shown in Fig. 1 (b) is carried out the A/D sampling, and the signal after will sampling is sent into the complex coefficient digital filter that equates with the carrier wave number and is handled, to separate the entrained signal of different carrier, resulting receiver is referred to as the multi-carrier receiver structure based on the modulation type bank of filters.

At transmitting terminal, the modulation type transmitting filter group that the information elder generation parallel passes that each carrier wave is carried in advance is made up of the complex coefficient digital filter that equates with the carrier wave number obtains having the baseband signal of the frequency spectrum shown in Fig. 1 (b); And then upconvert to radio frequency or high intermediate frequency simultaneously.Signal after the up-conversion has the frequency spectrum shown in Fig. 1 (a).Resulting like this transmitter is referred to as the multicarrier transmitter structure based on the modulation type bank of filters.

Be configured to example with cdma2000 three carrier waves, as shown in Figure 2 based on the structure of the transmitter of modulation type bank of filters and zero intermediate frequency reciver.If channel is distortion not, then adopt this structure accurately to rebuild transmission signal on former each carrier wave at receiving terminal.

P among Fig. 2₁, p₂, p₃Represent the transmission information on each carrier wave respectively,

Be illustrated respectively in the information on each carrier wave of rebuilding in the receiver.↑ M represents M times of up-sampling, and ↓ M represents M times of down-sampling.In the configuration of cdma2000 three carrier waves, M=4; H_k(z), k=-1, the required digital filter of 0,1 respectively corresponding first, second and third carrier signal; K₀(z) be the low-pass prototype digital filter, its impulse response coefficient is h (n).The impulse response coefficient of each filter is respectively:

Wherein2, the simplification of receiving terminal modulation type bank of filters realizes

If the exponent number of the low-pass prototype digital filter impulse response h (n) that provides in [formula 3] is that (for the configuration of three carrier waves in the cdma2000, the low-pass prototype digital filter exponent number L value of its transmitting terminal is 48 to L.), its heterogeneous being decomposed into:

Wherein, the q of lowpass prototype filter H (z) heterogeneous element is:

Then the heterogeneous of each filter is decomposed into:

Following formula is expressed as the form of two matrix multiples:

Obtain the simplification implementation structure of the heterogeneous decomposition of multicarrier DS-CDMA system receiving filter group thus, as shown in Figure 3.

Matrix T among Fig. 3 is:

3, the simplification of transmitting terminal modulation type bank of filters realizes

In like manner, can obtain the simplification implementation structure of the heterogeneous decomposition of multicarrier DS-CDMA system transmitting filter group by Fig. 2 and [formula 7], as shown in Figure 4.Matrix T among Fig. 4^HThe conjugate transpose of representing matrix T, concrete value is as follows:

4. computational complexity relatively

Be configured to example explanation the present invention in the advantageous characteristic aspect the reduction implementation complexity with cdma2000 three carrier waves.Handle the criterion of required multiplication accumulative frequency with each input sample as implementation complexity.

With for three carrier receivers,, be 3L then for the required multiplication accumulative frequency of each input sample if adopt structure as shown in Figure 2 to be realized.If adopt heterogeneous decomposition as shown in Figure 4 to simplify the reception structure, then owing to all filtering operations only need to carry out on 1/M sampling speed, and M the heterogeneous element that filter is a lowpass prototype filter, its total length is L.Consider that the operation matrix T shown in [formula 8] need not multiplying, thereby for each sampled input signal, heterogeneous decomposition shown in Figure 4 receives the required multiplication accumulative frequency of structure and is: L multiplication accumulating operation and 12 sub-addition computings.Hence one can see that, can make implementation complexity reduce about 3M=12 doubly on the basis of reception structure shown in Figure 2 based on the receiver structure of heterogeneous decomposition.

Can obtain similar result for transmitting terminal.Adopt its implementation complexity of dispensing device direct implementation more shown in Figure 2 of heterogeneous decomposition can reduce about 3M=12 doubly.

Beneficial effect of the present invention: the present invention is directed to multicarrier DS-CDMA system, propose a kind ofly can give full play to the digital processing ability, save the transmission and the method for reseptance of hardware resource to greatest extent.Its basic characteristics are at the digital processing technology of transmitting terminal and receiving terminal employing modulation type bank of filters, need not a plurality of parallel simulation process devices, thereby make the realization of system reliable more economically.Adopt heterogeneous decomposition that transmitting terminal and the required a plurality of filters of receiving terminal are decomposed and simplification, reduced implementation complexity.The present invention can be used for comprising any multi-carrier mobile communication system of cdma2000-3x.

(4) description of drawings:

Fig. 1 (a) is radio frequency (or the high intermediate frequency) spectrum diagram of three carrier signals, (b) is three carrier wave base band letters

Number spectrum diagram;

Fig. 2 is the structural representation of the modulation type bank of filters of the transmission of three carrier waves and reception;

Fig. 3 is the simplification implementation structure of the heterogeneous decomposition of multicarrier DS-CDMA system receiving filter group;

Fig. 4 is the simplification implementation structure of the heterogeneous decomposition of multicarrier DS-CDMA system transmitting filter group;

Fig. 5 is the multicarrier DS-CDMA system receiving system block diagram based on heterogeneous decomposition;

Fig. 6 is the multicarrier DS-CDMA system transmitter block diagram based on heterogeneous decomposition;

Fig. 7 is based on the multicarrier DS-CDMA system transmitter exemplifying embodiment of heterogeneous decomposition

Fig. 8 is based on frequency receiver exemplifying embodiment in the multicarrier DS-CDMA system zero of heterogeneous decomposition.

(5) embodiment:

Further specify device for carrying out said of the present invention below in conjunction with drawings and Examples

Downsampling device (device 1) to every M input data sampling once, obtains a data output.Up-sampling device (device 2) to each input data sampling once and export this data, and is exported M-1 zero before to next sampling input data more continuously.Filter apparatus (device 3) is a FIR mode filter, and the dependence between the prototype filter h (n) of its impulse response coefficient and system is shown in [formula 5].Matrix operating device (device 4/ device 5) is finished the phase multiplication of two matrixes shown in [formula 7].

Fig. 5 is based on the receiving system block diagram of the multi-carrier CDMA system of heterogeneous decomposition, it by M times of down-sampler device (device 1), filter apparatus (device 3), time-delay mechanism and matrix operating device (device 4) totally four kinds of processing unit form.For M times of down-sampler device (device 1), its input is through the data after the A/D sampling, and to every M input data sampling once, obtains a data output.For filter apparatus (device 3), it carries out filtering to the data from M times of down-sampler device, finishes the FIR filtering shown in [formula 5].For matrix operating device (device 4), its input is exported from the filtering of M filter apparatus, and finishes the matrix operation shown in [formula 7].For the cdma2000-3x system, its operation matrix T is shown in [formula 8].

Fig. 6 is based on the dispensing device block diagram of the multi-carrier CDMA system of heterogeneous decomposition, it by M times of up-sampler device (device 2), filter apparatus (device 3), time-delay mechanism, adder and matrix operating device (device 5) totally five kinds of processing unit form.For matrix operating device (device 5), it be input as the information that each carrier wave carries in advance, and finish the matrix operation shown in [formula 7], for the cdma2000-3x system, its operation matrix is the T shown in [formula 9]^H, the operation result correspondence is sent to M filter apparatus.For filter apparatus (device 3), it finishes the FIR filtering shown in [formula 5] to carrying out filtering from the data of matrix operating device (device 5), and the result is outputed to M times of up-sampler device (device 2).For M times of up-sampler device (device 2), its input is through filtered data, and it to each input data sampling once and export this data and exports M-1 zero more continuously before to next sampling input data.The output of M up-sampler device is respectively through exporting after the time-delay of as shown in figure 10 correspondence and the addition.

Fig. 7 and Fig. 8 are respectively based on the transmission of the multicarrier DS-CDMA system of heterogeneous decomposition and the schematic diagram that the zero intermediate frequency receiving system is implemented in the cdma2000-3x system.The exemplifying embodiment of the dispensing device shown in Figure 11 (a) comprises dispensing device, D/A conversion equipment and the radio frequency handling device of the heterogeneous decomposition of modulation type bank of filters.Wherein radio frequency handling device is finished the upconversion process to the dispensing device output signal of the heterogeneous decomposition of modulation mode filter group, promptly base band D/A output signal is modulated to high intermediate frequency or radio frequency.The exemplifying embodiment of the receiving system shown in Figure 11 (b) comprises radio frequency front-end device, A/D sampling apparatus, the heterogeneous decomposition implement device of modulation type bank of filters and multipath RAKE receiving system.Wherein radio frequency front-end device is finished the radio frequency of reception or the down-converted of high intermediate frequency multi-carrier signal, and the centre frequency that makes mean carrier is a zero frequency, and the baseband signal after the down-converted is carried out low-pass filtering.The A/D sampling apparatus is finished the sampling output to the base band multi-carrier signal, and its sample frequency is 4 * 1.2288Msps, and the implement device of the heterogeneous decomposition of modulation type bank of filters is sent in sampling output with serial mode.The multipath that RAKE receiver is finished single carrier signal merges reception.

Claims (3)

Translated fromChinese

1、基于多相分解的多载波CDMA系统发送与零中频的接收方法，其特征在于：在接收端，将多载波DS-CDMA接收信号从射频或高中频下变频至基带，以使多个载波的中间一个载波的中心频率为零频率，运用最低的采样频率进行采样，以调制型滤波器组替代多载波数字滤波器，在分离多个载波接收信号并重建原各个载波上的发送信号的同时，利用多相分解简化接收机的实现结构，降低接收机的硬件实现复杂度，在发送端，同样以调制型滤波器组替代多载波数字滤波器，在将各载波预携带的信息并行经过调制型发送滤波器组的同时，利用多相分解简化发射机的实现结构，然后同时上变频到高中频或射频。1. The multi-carrier CDMA system transmission and zero-IF receiving method based on polyphase decomposition is characterized in that: at the receiving end, the multi-carrier DS-CDMA reception signal is down-converted from radio frequency or high-frequency to baseband, so that multiple carriers The center frequency of the middle carrier is zero frequency, and the lowest sampling frequency is used for sampling, and the multi-carrier digital filter is replaced by a modulated filter bank. While separating multiple carrier receiving signals and reconstructing the original sending signals on each carrier , using polyphase decomposition to simplify the implementation structure of the receiver and reduce the hardware implementation complexity of the receiver. At the sending end, the multi-carrier digital filter is also replaced by a modulated filter bank, and the information pre-carried by each carrier is modulated in parallel. At the same time, polyphase decomposition is used to simplify the implementation structure of the transmitter, and then the frequency is up-converted to IF or RF at the same time.2、如权利1要求所述的基于多相分解的多载波CDMA系统发送与零中频的接收装置，其特征在于：接收装置由M倍下采样器装置(装置1)、滤波器装置(装置3)、延时装置和矩阵运算装置(装置4)共四种处理装置组成，对于M倍下采样器装置(装置1)，它的输入是经过A/D采样后的数据，并对每M个输入数据采样一次，得到一个数据输出，对于滤波器装置(装置3)，它对来自M倍下采样器装置的数据进行滤波，完成如[公式5]所示的FIR滤波，对于矩阵运算装置(装置4)，它的输入来自M个滤波器装置的滤波输出，并完成如[公式7]所示的矩阵运算，对于cdma2000-3x系统，其运算矩阵T如[公式8]所示。2. The multi-carrier CDMA system based on polyphase decomposition as claimed in claim 1 sends and the receiving device of zero intermediate frequency, it is characterized in that: the receiving device is composed of M times downsampler device (device 1), filter device (device 3 ), a delay device and a matrix operation device (device 4) are composed of four processing devices, for the M times downsampler device (device 1), its input is the data after A/D sampling, and for each M The input data is sampled once to obtain a data output. For the filter device (device 3), it filters the data from the M times downsampler device to complete the FIR filtering shown in [Formula 5]. For the matrix operation device ( Device 4), its input comes from the filtered output of M filter devices, and completes the matrix operation shown in [Formula 7]. For the cdma2000-3x system, its operation matrix T is shown in [Formula 8].3、如权利1要求所述的基于多相分解的多载波CDMA系统发送与零中频的接收装置，其特征在于：发送装置由M倍上采样器装置(装置2)、滤波器装置(装置3)、延时装置、加法器和矩阵运算装置(装置5)共五种处理装置组成，对于矩阵运算装置(装置5)，它的输入为各载波预携带的信息，并完成如[公式7]所示的矩阵运算，对于cdma2000-3x系统，其运算矩阵为如[公式9]所示的T¹¹，运算结果对应送往M个滤波器装置，对于滤波器装置(装置3)，它对来自矩阵运算装置(装置5)的数据进行滤波，完成如[公式5]所示的FIR滤波，并将结果输出到M倍上采样器装置(装置2)，对于M倍上采样器装置(装置2)，其输入是经过滤波后的数据，它对每一个输入数据采样一次并输出该数据，且在对下一个输入数据进行采样前再连续输出M-1个零，M个上采样器装置的输出分别经过如图10所示的对应的延时及相加后输出。3, the multi-carrier CDMA system based on polyphase decomposition as claimed in claim 1 sends and the receiving device of zero intermediate frequency, it is characterized in that: sending device is by M times upsampler device (device 2), filter device (device 3 ), a delay device, an adder, and a matrix operation device (device 5) are composed of five processing devices. For the matrix operation device (device 5), its input is the information carried in advance by each carrier, and it is completed as [formula 7] For the matrix operation shown in the cdma2000-3x system, its operation matrix is T¹¹ as shown in [Equation 9], and the operation results are correspondingly sent to M filter devices. For the filter device (device 3), it is for the The data of the matrix operation device (device 5) is filtered, and the FIR filtering shown in [formula 5] is completed, and the result is output to the M times upsampler device (device 2), for the M times upsampler device (device 2 ), whose input is filtered data, it samples each input data once and outputs the data, and outputs M-1 zeros continuously before sampling the next input data, M upsampler devices The output is output after corresponding delay and addition as shown in FIG. 10 .

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