CN102026397B - Data demodulation method and equipment for physical random access channel - Google Patents

Abstract

The invention discloses data demodulation method and equipment for a physical random access channel. The method comprises the following steps of: adjusting a received physical random access channel frequency to near a zero frequency; inhibiting interference outside the physical random access channel; sampling once at each M sampling points; performing fast Fourier transform for N sampling points; and extracting 839 or 139 points from frequency domain signals of N sampling points subjected to fast Fourier transform. In the invention, a wave filter with low complexity can be utilized for filtering waves, and further the demodulation of the physical random access channel can be completed by utilizing general fast Fourier transform operation. As a low-level wave filter can be adopted to realize demodulation, the method overcomes the defects that a lot of multiplier units or adding devices are needed during adopting a high-level wave filter and the signal delay ratio is larger.

Description

Data demodulation method on a kind of Physical Random Access Channel and equipment

Technical field

The present invention relates to mobile communication technology, particularly data demodulation method and the equipment on a kind of Physical Random Access Channel.

Background technology

SD (Synchronization Detection synchronously detects) algorithm, for the foundation of uplink synchronous process, is that the physical layer base band signal process of random access procedure realizes part.Detect by realizing uplink synchronous, can complete UE (User Equipment, subscriber equipment) and eNodeB (evolution base station) between connection, thereby make UE obtain eNodeB uplink resource allocation and prepare for normal transmitting uplink data.

Fig. 1 is LTE (Long Term Evolution, Long Term Evolution) uplink random access input block diagram, in figure, provide PRACH (Physical Random Access Channel, the Physical Random Access Channel) position of demodulation part in whole SD subsystem.

The general principle of PRACH demodulation is time domain sequences to be carried out to DFT (Discrete FourierTransform, discrete Fourier transform (DFT)) conversion obtain frequency domain sequence, and algorithm complex depends primarily on counting of DFT conversion.Because PRACH channel distortion experienced is spaced apart 1/12 or 1/2 of common subcarrier spacing, to count corresponding be data FFT points N for FFT (Fast Fourier Transform, fast fourier transform) conversion _ffi12 times.For example: it is 24576 that the FFT conversion of Preamble under 20M bandwidth (targeting sequencing) form 0 correspondence is counted.Therefore, a problem of systems face is: if directly carry out the DFT conversion of 24576, complexity can be very high.

In fact PRACH only takies 6 PRB (physical resource block of Whole frequency band, Physical Resource Block), Whole frequency band is done to obviously relatively waste of DFT, therefore general way is first to adopt filter that the frequency-region signal of PRACH is leached, and then down-sampled, so just can reduce counting of DFT conversion, thereby reduce algorithm implementation complexity.

Convert for different DFT the prior art of counting two kinds of PRACH demodulating algorithms are provided, one is DFT conversion scheme, and another kind is time-domain filtering scheme.Wherein, DFT conversion scheme is more directly perceived, in the time there is N PRACH frequency domain channel in a subframe, only can obtain all PRACH frequency-region signals by a DFT conversion.Therefore, this scheme is mainly applicable to the DFT less situation of counting, and for DFT, conversion is counted when larger, and implementation complexity is very high; The DFT conversion needing is counted less, and after filtering, minimum 1024 just can satisfy the demands.Therefore, filter scheme is mainly applicable to DFT and converts the larger situation of counting.

Generally, counting of the DFT conversion of PRACH is all larger, and is not 2 integral number power, can not directly adopt general FFT conversion.Be mainly that example illustrates technical problem with the DFT of 0,24576 of preamble form below.Direct Transform method can be decomposed into 4 by 24576 ⁶* 2*3, realizes by the FFT of 6 bases 4, a base 2 and a base 3.This method computation complexity is larger, and the memory cell taking is many.

Time-domain filtering method is according to PRACH frequency domain distribution feature, adds down-sampled method realize by the filter that is easy to realize.This scheme implementation procedure more complicated, and have certain performance loss.Whether meet system needs, also need further assessment.

In sum, the deficiencies in the prior art are: directly DFT processing scheme algorithm is intuitively simple, but implementation complexity is too high, need a large amount of addition and multiplying, also need more memory cell.

The interference of FIR (finite impulse response) filtering algorithm outside can reasonable filtering PRACH channel, computing by down-sampled minimizing FFT is counted, thereby greatly simplify the computation complexity of DFT, but, the filter of high-order still needs a large amount of multipliers or adder, and signal delay is larger.In addition, the characteristic of filter and number of taps and tap coefficient have relation, are difficult to according to the configuring condition flexible configuration of PRACH.

Summary of the invention

The invention provides data demodulation method and equipment on a kind of PRACH, separate timing at PRACH and need to adopt a large amount of multipliers or adder because of the filter that uses high-order in order to solve in prior art, and the larger problem of signal delay.

Data demodulation method on a kind of PRACH is provided in the embodiment of the present invention, has comprised the steps:

The PRACH data spectrum receiving is adjusted to zero-frequency both sides;

Suppress the interference outside PRACH channel;

Adopt sample one time at every M sampling point;

N sampled point carried out to fast fourier transform FFT, and M, N meet M*N=24576 or 4096;

In the frequency-region signal of the sampled point of the N from FFT, extract or 139 points at 839.

Data demodulates on a kind of PRACH equipment is provided in the embodiment of the present invention, has comprised:

Frequency regulation block, for adjusting to zero-frequency both sides by the PRACH data spectrum receiving;

Filter module, for suppressing the interference outside PRACH channel;

Down-sampled module, for adopting sample one time at every M sampling point;

N point FFT module, for N sampled point carried out to FFT, M, N meet M*N=24576 or 4096;

839/139 extraction module, extracts or 139 points at 839 for the frequency-region signal of the sampled point of the N from FFT.

Beneficial effect of the present invention is as follows:

The demodulation of the data of technical scheme provided by the invention on PRACH is adjusted to the PRACH frequency receiving near zero-frequency in implementing; Then suppress the interference outside PRACH channel; Adopt sample one time at every M sampling point; N sampled point carried out to FFT; In the frequency-region signal of last N sampled point from FFT, extract or 139 points at 839.

In technical scheme provided by the invention, utilize PRACH channel only to take the feature of one section of bandwidth, the PRACH frequency receiving is adjusted near zero-frequency, and then suppressed the interference outside PRACH channel; Therefore can utilize the filter that complexity is lower to carry out filtering, further can recycle general FFT and operated the demodulation of PRACH, realize demodulation owing to can adopting lower-order filter, therefore the filter that has overcome high-order needs a large amount of multiplier or adder, and the larger deficiency of signal delay.

Brief description of the drawings

Fig. 1 is LTE uplink random access input block diagram in background technology;

Fig. 2 is the data demodulation method implementing procedure schematic diagram on PRACH in the embodiment of the present invention;

Fig. 3 is the general solution block diagram of PRACH demodulation DFT shortcut calculation in the embodiment of the present invention;

Fig. 4 is the amplitude-versus-frequency curve schematic diagram of 127 rank FIR filters in the embodiment of the present invention;

Fig. 5 is CIC filtering method fundamental block diagram signal in the embodiment of the present invention;

Fig. 6 is 2 rank cic filter structural representations in the embodiment of the present invention;

Fig. 7 is that embodiment of the present invention intermediate frequency spectrum is moved the distribution schematic diagram of rear 3 PRACH at frequency domain;

Fig. 8 is 2 rank cic filter amplitude-frequency characteristic schematic diagrames of 6 times of extractions in the embodiment of the present invention;

Fig. 9 is the interior enlarged diagrams of 2 rank cic filter amplitude-frequency characteristic bands of 6 times of extractions in the embodiment of the present invention;

Figure 10 is 3 PRACH detection block figure signals simultaneously in the embodiment of the present invention;

Figure 11 is PRACH demodulation pre-treatment method implementing procedure schematic diagram in the embodiment of the present invention;

Figure 12 is the data demodulates device structure schematic diagram on PRACH in the embodiment of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described.

Fig. 2 is the data demodulation method implementing procedure schematic diagram on PRACH, and as shown in the figure, separating timing at PRACH can comprise the steps:

Step 201, the PRACH data spectrum receiving is adjusted to zero-frequency both sides;

Interference outside step 202, inhibition PRACH channel;

Step 203, adopt sample one time at every M sampling point;

Step 204, N sampled point carried out to FFT;

Wherein,, M, N meet M*N=24576 or 4096.

In the frequency-region signal of step 205, N sampled point from FFT, extract 839 or 139 points.

In technical scheme provided by the invention, basic thought is that employing filter is processed, and, first carries out frequency spectrum shift that is, then by low pass filter, then does down-sampledly, finally completes N point FFT and 839 or 139 data propositions.If while there is N PRACH channel in a subframe, only need to carry out corresponding N similarly operation.Fig. 3 is the signal of DFT shortcut calculation block diagram, as shown in the figure, comprise in basic implementation procedure: what step 201 was performed is frequency adjustment, what step 202 was performed is the interference suppressing outside PRACH channel, in this step, adopted filter to realize, what in figure, illustrate is also filter, and what step 203 was performed is down-sampled, that step 204 is performed is N point FFT, and what step 205 was performed is 839 or 139 extractions.

In enforcement, for 839 or the extraction of 139 for, PRACH has 5 kinds of forms at present, wherein: Format4 is that TDD (Time Division Duplex, time division duplex) is peculiar.The technical scheme that the embodiment of the present invention provides not only goes for wherein 4 kinds of forms of Format0～3 (i.e. 24576 inputs, 839 extractions), equally also be applicable to the 5th kind of form Format4 (4096 inputs, 139 extractions), and complexity is lower while implementing under Format4.

Will be mainly taking Format0～3 as example describes in the embodiment of the present invention, those skilled in the art also can apply to Format4 by the execution mode under Format0～3 as required.

Fig. 3 provides the general solution block diagram of PRACH demodulation DFT shortcut calculation.Again mainly with 24576 points, double is the main contents that example introduction is implemented with 4096 DFT below.

In step 201, the PRACH frequency receiving is adjusted near zero-frequency, the effect of this step is that the filter of being convenient to below uses simple conventional low pass filter to realize.

In step 202, suppress the interference outside PRACH channel, down-sampledly there is not the aliasing that noise and PUSCH (Physical Uplink Shared Channel, physical uplink link sharing channel) bring in order to what ensure 24576 PRACH.

Accordingly, if be that the spectral aliasing that noise and PUSCH bring does not occur for ensure 4096 PRACH down-sampled extracting 139 time.

In step 203, adopt M doubly to extract, every M sampling point is adopted once.The value of M is relevant with reduction procedure, in form Format0～3, is generally: 3,6,12 or 24.

Accordingly, in Format4, be 1,2,4,8 or 16.

In step 204, can adopt general FFT method to obtain.Wherein, for the value of N, in Format0～3, can be: 8192,4096,2048 or 1024.

Accordingly, in form Format4, can be 4096,2048,1024,512 or 256.

839 points in the middle of extracting the frequency-region signal of ordering from N in step 205.

Accordingly, in form Format4, be to extract 139 points.

In above each step implementation process, can adopt filter, traditional solution is the FIR filter that adopts a high-order, interference (other up channel and noise) outside filtering PRACH channel, doubly down-sampled through M, by a FFT that 24576/M is ordered, finally extract the preamble frequency domain data that obtains at 839 again.Choosing and the FFT below relation of having counted of the M value here and FIR filter.

And in implementation process of the present invention, the bandwidth occupying according to PRACH and the band that need to suppress disturb, can be easy to design the filter of satisfying the demand outward.Here can consider to adopt practical and convenient FIR filter, use 127 rank taps.Fig. 4 is the amplitude-versus-frequency curve schematic diagram of 127 rank FIR filters, in the time selecting FIR filter, in enforcement, just can draw with reference to this figure.In figure, Magnitude Response is amplitude-frequency response.

Further, in implementation process, because the FIR filter order adopting is higher, the complexity of realization is higher, it is also conceivable that the filter that adopts another kind of simple possible: cic filter (cascade integrator comb filter, or be called Hogenauer filter).

, can be in conjunction with down-sampled process in the invention process process, adopted cic filter to complete filtering and down-sampled process simultaneously., can adopt cic filter to suppress the interference outside PRACH channel, and adopt sample one time at every M sampling point.Fig. 5 is the signal of CIC filtering method fundamental block diagram, as shown in the figure, and compared with Fig. 2, having merged filtering and down-sampled process, is mainly to do low-pass filtering with cic filter in enforcement, does as required doubly down-sampled of M simultaneously, do again FFT computing, finally extract preamble.

Further, in implementation process, can, according to the feature that is continuous distribution to multiple PRACH channels in agreement 36.211, process multiple PRACH channels on frequency domain simultaneously, thereby save computing cycle and resource., taking 1 to 3 PRACH is one group, the PRACH frequency receiving is adjusted near zero-frequency simultaneously; Suppress the interference outside PRACH channel simultaneously; Adopt sample one time at every M sampling point simultaneously; N sampled point carried out to FFT simultaneously; In the frequency-region signal of N sampled point from FFT, extract or 139 points at 839 simultaneously.Introduce the concrete enforcement of which below.

Because frequency adjustment, N point FFT and 839 Extraction parts are close with general low-pass filtering scheme, thus the enforcement of article CIC filtering extraction here, and then set forth total solution.

Cic filter is derived from recursion rolling sum filter.Its amplitude-frequency response envelope is sin (x)/x type, thus cic filter be generally placed on high performance linear phase low pass tapped delay line FIR filter before or after, wherein FIR filter is the passband for compensating cic filter injustice.CIC has very high computational efficiency as narrowband low-pass filter, thereby hardware normal and extraction and interpolation links together in Modern Communication System.

Fig. 6 is 2 rank cic filter structural representations, and wherein R represents the multiple extracting.As seen from the figure, this cic filter combines filtering and abstraction module, jointly completes filtering and down-sampled process, and its filtering characteristic is determined by filtering exponent number and extracting multiple R completely, can need to select this two parameters according to design.

Be it can also be seen that by Fig. 6, cic filter implementation complexity is very low, and without any need for multiply operation and a large amount of storages, processing delay is also very little, is applicable to very much hardware system and realizes.

Cause the problem of register spilling about the unit negative feedback meeting on every grade of integrator of cic filter, can consider to solve with 2 complement code algorithm.As long as the word length of integrator can be held the maximum difference between any two adjacent sampled values, utilization has by periodically reel 2 complementary binary form of character of mould, and the comb filter of following below can calculate the correct difference between adjacent integrator output sample.

In LTE system, need to consider to detect at most 6 PRACH, general way is to do 6 times similarly to calculate or 6 tunnel parallel processings, but such processing can increase the time of system processing or need more hardware resource.

Research to standard is known, and being sent on frequency domain of PRACH is partial continuous.For example send 6 PRACH, 3 PRACH send on one section of continuous PRB, and another three PRACH send on another section of continuous PRB.Therefore, in concrete enforcement, 6 PRACH can be divided into two groups, then detect PRACH according to processing procedure below.

Fig. 7 is that after frequency spectrum shift, 3 PRACH, at the distribution schematic diagram of frequency domain, do frequency adjustment (frequency spectrum shift) centered by that in the middle of three PRACH, that is, and and the centre by frequency spectrum shift to simultaneously treated PRACH bandwidth.Frequency spectrum after moving is as shown in 7.

Fig. 8 is 2 rank cic filter amplitude-frequency characteristic schematic diagrames of 6 times of extractions, and Fig. 9 is the interior enlarged diagrams of 2 rank cic filter amplitude-frequency characteristic bands of 6 times of extractions.

Interference beyond three PRACH of filter filtering after frequency spectrum shift, basic scheme can be: do 6 times of extractions with 2 rank cic filter filtering simultaneously, obtain 4096 sampling points.That is, be one group at taking 1 to 3 PRACH, in the time that every M sampling point is adopted a sample, can do 6 times of extractions with 2 rank cic filter filtering simultaneously simultaneously, obtain 4096 sampling points.Fig. 8 has provided the amplitude-versus-frequency curve of 6 times of extraction cic filters.

Fig. 9 has amplified the interior part of band of Fig. 8, and as seen from the figure, for 1.5 PRACH bandwidth 864*1.5*1.25kHz=1.62MHz, in band, maximum attenuation is 3dB.

Figure 10 is 3 PRACH detection block figure signals simultaneously, as shown in the figure, is 4096 FFT after filtering, chooses respectively three data corresponding to PRACH and carries out PRACH detection.

Generally, it is not very high that random access testing system requires PRACH demodulation part, and in CIC band, 3dB decay can't affect last detection performance.If but wished to weaken the impact of decline on performance in band, the FIR filter of the low order of can connecting after cic filter makes to export narrowed width and passband gain is smooth.The Frequency and Amplitude response ideal situation of this compensation FIR filter should be the contrary of cic filter passband response., the FIR filter of the low order of connecting after cic filter, uses so that output narrowed width and passband gain are smooth.Further, the response of the Frequency and Amplitude of the FIR filter of low order can be the contrary of cic filter passband response.

Provide the coefficient of the compensation FIR filter of three rank 15 taps below:

[-1，4，-16，32，-64，136，-352，1312，-352，136，-64，32，-16，4，-1]/790

Further, in enforcement, can also comprise:

Before carrying out random access detection, physical layer obtains the information of PRACH configuration information and uplink-downlink configuration from high level;

According to the information acquisition preamble code time-frequency mapping of PRACH configuration information and uplink-downlink configuration;

Determine number, frequency translation position, M, N one of them or its combination of processing PRACH according to preamble code time-frequency mapping.

In concrete enforcement, before physical layer is carried out random access detection, obtain the information of PRACH configuration and uplink-downlink configuration from high level, can obtain preamble code time-frequency by tabling look-up and may access situation.Like this, in PRACH demodulation process, just can select as the case may be different processing modes and parameter, comprise: process several PRACH, frequency translation position, down-sampled multiple M, FFT points N etc.

Figure 11 is PRACH demodulation pre-treatment method implementing procedure schematic diagram, as shown in the figure, can comprise the steps:

Step 1101, read high layer information, obtain the mapping of preamble video;

Step 1102, definite PRACH number and each demodulation parameter processed;

Step 1103, frequency spectrum shift, CIC filtering extraction, N point FFT and preamble extract

In enforcement, determine that PRACH number refers to according to the preamble time-frequency mapping obtaining and can know the current PRACH number that may access and time domain and frequency domain position, can select thus Yong Yi road or two-way PRACH to process, and process several PRACH simultaneously.For example, obtaining PRACH configuration index from high level is 18, UL/DL (uplink/downlink) configuration index is 5, show 5.7.1-4 by 3GPP TS 36.211 and can know currently may have 6 PRACH to access simultaneously, therefore PRACH processing scheme selection two-way PRACH processes, and 3 PRACH are processed on each road simultaneously, frequency spectrum shift is centered by middle PRACH, calculate frequency spectrum shift point, the extracting multiple M of cic filter selects 6, FFT points N to select the preamble code of 4096 and 3 PRACH channels to extract simultaneously simultaneously.

Above arrangements is flexible, can select different processing units and suitable parameter according to different configurations, can maximally utilise like this hardware resource, reduces unnecessary power consumption.For example, if known may have a PRACH access at first field simultaneously, that just need to not process PRACH at second field again, in addition, when processing PRACH, also only need a road to process, and do not enable another road work, simultaneously, cic filter extracting multiple M can select 12 or 24, and corresponding FFT points N selects 2048 or 1024.Such processing is simple, and very good to the reduction of system power dissipation, and simple CIC filters solutions has ensured the possibility of such flexible configuration.

Based on same inventive concept, a kind of PRACH demodulated equipment is also provided in the embodiment of the present invention, because the principle that this equipment is dealt with problems is similar to PRACH demodulation method, therefore the enforcement of this equipment can be referring to the enforcement of method, repeats part and repeat no more.

Figure 12 is PRACH demodulated equipment structural representation, as shown in the figure, in demodulated equipment, can comprise:

Frequency regulation block 1201, for adjusting to zero-frequency both sides by the PRACH data spectrum receiving;

Filter module 1202, for suppressing the interference outside PRACH channel;

Down-sampled module 1203, for adopting sample one time at every M sampling point;

N point FFT module 1204, for N sampled point carried out to FFT, M, N meet M*N=24576 or 4096;

839/139 extraction module 1205, extracts or 139 points at 839 for the frequency-region signal of the sampled point of the N from FFT.

In enforcement, first frequency regulation block is carried out frequency spectrum shift, then by having adopted the filter module filtering of low pass filter, then do down-sampledly through down-sampled module, finally complete N point FFT and at 839 by N point FFT module, 839/139 extraction module or 139 data propose.If while there is N PRACH channel in a subframe, only need to carry out N similarly operation.

Taking 24576 points, 4096 DFT as example, in enforcement, demodulated equipment can be:

Frequency regulation block is adjusted to the PRACH frequency receiving near zero-frequency, and the filter module of being convenient to below can use simple conventional low pass filter to realize.

Filter module suppresses the interference outside PRACH channel, and what in the time extracting at 839, ensure 24576 points or in the time extracting at 139, ensure 4096 PRACH down-sampled the aliasing that noise and PUSCH bring does not occur.

Down-sampled module adopts M doubly to extract, and every M sampling point is adopted once.The value of M is relevant with reduction procedure, and general M is in Format0～3: 3,6,12 or 24, and in form Format4, be 1,2,4,8 or 16.

N point FFT module can adopt general FFT method to obtain.N can be in Format0～3: 8192,4096,2048 or 1024, and in form Format4, can be 4096,2048,1024,512 or 256.

839/139 extraction module is 839 or 139 points in the middle of extracting the frequency-region signal of ordering from N.

Therefore in enforcement, can be:

Filter module is low pass filter.Further, filter module can be high order FIR filter.

Filter module can be further used in order to there is not the spectral aliasing that noise and PUSCH bring extracting ensure 24576 points 839 time or ensure 4096 PRACH in the time extracting at 139 down-sampled.

Down-sampled module can be further used for adopting M in Format0～3 to be: 3,6,12 or 24, and in form Format4, be 1,2,4,8 or 16.

N point FFT module can be further used for adopting N in Format0～3 to be: 8192,4096,2048 or 1024, and in form Format4, be 4096,2048,1024,512 or 256.。

In enforcement, filter module with can be cic filter by sampling module.In conjunction with down-sampled process, adopt cic filter to complete filtering and down-sampled process simultaneously.Its role is to, do low-pass filtering with cic filter, do as required doubly down-sampled of M simultaneously, then do FFT computing, finally extract preamble.

The structure chart of the 2 rank cic filters that provided from aforesaid Fig. 6, cic filter combines filtering and abstraction module, jointly complete filtering and down-sampled process, its filtering characteristic is determined by filtering exponent number and extracting multiple R completely, can need to select this two parameters according to design.Be it can also be seen that by Fig. 6, cic filter implementation complexity is very low, and without any need for multiply operation and a large amount of storages, processing delay is also very little, is applicable to very much hardware system and realizes.

In enforcement, in equipment, can further include:

The FIR filter of low order, is connected on after cic filter, for making to export narrowed width and passband gain is smooth.Further, the response of the Frequency and Amplitude of the FIR filter of low order can be the contrary of cic filter passband response.

The effect of the FIR filter of the low order of connecting after cic filter is, generally, it is not very high that random access testing system requires PRACH demodulation part, and in CIC band, 3dB decay can't affect last detection performance.If but wished to weaken the impact of decline on performance in band, the FIR filter of the low order of can connecting after cic filter makes to export narrowed width and passband gain is smooth.The Frequency and Amplitude response ideal situation of this compensation FIR filter should be the contrary of cic filter passband response.

According to the feature that is continuous distribution on frequency domain to multiple PRACH channels in agreement 36.211, can process 3 PRACH channels simultaneously, thereby save computing cycle and resource.Therefore, in enforcement,

Frequency regulation block can be further used for taking 1 to 3 PRACH and be one group, the PRACH frequency receiving is adjusted near zero-frequency simultaneously;

Filter module can be further used for taking 1 to 3 PRACH and be one group, suppresses the interference outside PRACH channel simultaneously;

Down-sampled module can be further used for taking 1 to 3 PRACH and be one group, adopts sample one time at every M sampling point simultaneously;

N point FFT module can be further used for taking 1 to 3 PRACH and be one group, N sampled point is carried out to FFT simultaneously;

839/139 extraction module can be further used for taking 1 to 3 PRACH and be one group, extracts or 139 points at 839 in the frequency-region signal of N sampled point from FFT simultaneously.

In concrete enforcement, filter module can also be further used for being one group at taking 1 to 3 PRACH, while suppressing the interference outside PRACH channel, frequency spectrum shift is arrived to the centre of simultaneously treated PRACH bandwidth simultaneously.

Down-sampled module can also be further used for being one group at taking 1 to 3 PRACH, in the time that every M sampling point is adopted a sample, does 6 times of extractions with 2 rank cic filter filtering simultaneously simultaneously, obtains 4096 sampling points.

If obtained the information of PRACH configuration and uplink-downlink configuration from high level before physical layer is carried out random access detection, can obtain preamble code time-frequency by tabling look-up and may access situation.Like this, in PRACH demodulation process, just can select as the case may be different processing modes and parameter, comprise: process several PRACH, frequency translation position, down-sampled multiple M, FFT points N etc.Therefore,, in enforcement, in equipment, can further include:

Parameter determination module 1206, obtains the information of PRACH configuration information and uplink-downlink configuration from high level for carry out random access in physical layer before detecting; According to the information acquisition preamble code time-frequency mapping of PRACH configuration information and uplink-downlink configuration; Determine number, frequency translation position, M, N one of them or its combination of processing PRACH according to preamble code time-frequency mapping.

Determine that PRACH number refers to according to the preamble time-frequency mapping obtaining and can know the current PRACH number that may access and time domain and frequency domain position, can select thus Yong Yi road or two-way PRACH to process, and process several PRACH simultaneously.For example, obtaining PRACH configuration index from high level is 18, UL/DL configuration index is 5, show 5.7.1-4 by 3GPP TS 36.211 and can know currently may have 6 PRACH to access simultaneously, therefore PRACH processing scheme selection two-way PRACH processes, and 3 PRACH are processed on each road simultaneously, frequency spectrum shift is centered by middle PRACH, calculate frequency spectrum shift point, the extracting multiple M of cic filter selects 6, FFT points N to select the preamble code of 4096 and 3 PRACH channels to extract simultaneously simultaneously.

The benefit of this scheme is flexible configuration, selects different processing units and suitable parameter according to different configurations, can maximally utilise like this hardware resource, reduces unnecessary power consumption.For example, if known may have a PRACH access at first field simultaneously, that just need to not process PRACH at second field again, in addition, when processing PRACH, also only need a road to process, and do not enable another road work, simultaneously, cic filter extracting multiple M can select 12 or 24, and corresponding FFT points N selects 2048 or 1024.Such processing is simple, and very good to the reduction of system power dissipation, and simple CIC filters solutions has ensured the possibility of such flexible configuration.

For convenience of description, the each several part of the above device is divided into various modules with function or unit is described respectively.Certainly, in the time that enforcement is of the present invention, the function of each module or unit can be realized in same or multiple software or hardware.

From above-described embodiment, in the invention process, utilize PRACH channel only to take the feature of one section of bandwidth, utilize the cic filter that complexity is very low to carry out filtering extraction, recycle general FFT and operated the demodulation of PRACH.Can also be simultaneously according to the feature flexible configuration PRACH demodulation scheme of cic filter.Concrete:

The process of utilizing frequency spectrum shift, filtering, down-sampled, FFT and preamble to extract in the invention process realizes the demodulating process of PRACH.

Further, in enforcement, can utilize the interference outside low pass filter filtering PRACH channel strip, just can utilize the FFT computing demodulation of counting lower after down-sampled.

Further, in enforcement, above-mentioned low-pass filtering can adopt high order FIR filter to realize.

Further, in enforcement, above-mentioned low-pass filtering adds down-sampled process and can adopt cic filter to complete.

Further, in enforcement, above-mentioned cic filter adopts the filtering of rank, M >=1 to realize, and extracting multiple can be chosen according to filtering requirements and actual needs.

Further, in enforcement, above-mentioned CIC decimation filter can further improve performance by series connection low order FIR filter.

Further, in enforcement, can determine demodulation scheme according to PRACH and UL/DL configuration.

Further, in enforcement, above-mentioned demodulation scheme comprises that 1 road is to 6 tunnel demodulation PRACH, and in enforcement, 1 to 3 PRACH can be processed in each road simultaneously.

Further, in enforcement, above-mentioned while processing several PRACH, frequency spectrum can be moved the centre of simultaneously treated PRACH bandwidth simultaneously.

Further, in enforcement, above-mentioned while processing several PRACH, CIC extracting multiple, FFT count and extract all relevant with PRACH treating number with preamble simultaneously.

In technical scheme provided by the invention, adopt cic filter design, realized very high PRACH demodulating process of counting.Major advantage is compared to existing technology that flexible design and complexity are very low.The characteristic of cic filter is only relevant with extracting multiple and exponent number, therefore flexible configuration extracting multiple and filter order as required.Implement technical scheme provided by the invention and can also select flexibly PRACH demodulation scheme and parameter according to the Given information obtaining from upper strata, and general FIR filter can not design so flexibly.

In addition, cic filter compares direct FFT method and FIR filtered method complexity is very low, just can realize without any need for multiplier.Even for the very high situation of performance requirement, cic filter also can be realized by the simple FIR filter of series connection low order, compares high order FIR filter and still has the feature that complexity is low.

Those skilled in the art should understand, embodiments of the invention can be provided as method, system or computer program.Therefore, the present invention can adopt complete hardware implementation example, completely implement software example or the form in conjunction with the embodiment of software and hardware aspect.And the present invention can adopt the form at one or more upper computer programs of implementing of computer-usable storage medium (including but not limited to magnetic disc store, CD-ROM, optical memory etc.) that wherein include computer usable program code.

The present invention is with reference to describing according to flow chart and/or the block diagram of the method for the embodiment of the present invention, equipment (system) and computer program.Should understand can be by the flow process in each flow process in computer program instructions realization flow figure and/or block diagram and/or square frame and flow chart and/or block diagram and/or the combination of square frame.Can provide these computer program instructions to the processor of all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device to produce a machine, the instruction that makes to carry out by the processor of computer or other programmable data processing device produces the device for realizing the function of specifying at flow process of flow chart or multiple flow process and/or square frame of block diagram or multiple square frame.

These computer program instructions also can be stored in energy vectoring computer or the computer-readable memory of other programmable data processing device with ad hoc fashion work, the instruction that makes to be stored in this computer-readable memory produces the manufacture that comprises command device, and this command device is realized the function of specifying in flow process of flow chart or multiple flow process and/or square frame of block diagram or multiple square frame.

These computer program instructions also can be loaded in computer or other programmable data processing device, make to carry out sequence of operations step to produce computer implemented processing on computer or other programmable devices, thereby the instruction of carrying out is provided for realizing the step of the function of specifying in flow process of flow chart or multiple flow process and/or square frame of block diagram or multiple square frame on computer or other programmable devices.

Although described the preferred embodiments of the present invention, once those skilled in the art obtain the basic creative concept of cicada, can make other change and amendment to these embodiment.So claims are intended to be interpreted as comprising preferred embodiment and fall into all changes and the amendment of the scope of the invention.

Claims (16)

1. the data demodulation method on Physical Random Access Channel, is characterized in that, comprises the steps:

The PRACH data spectrum receiving is adjusted to zero-frequency both sides;

Suppress the interference outside PRACH channel;

Adopt sample one time at every M sampling point;

N sampled point carried out to fast fourier transform FFT, and M, N meet M*N=24576 or 4096;

In the frequency-region signal of the sampled point of the N from FFT, extract or 139 points at 839;

Adopt cascade integrator comb cic filter to suppress the interference outside PRACH channel, and adopt this cic filter to adopt sample one time at every M sampling point;

Taking 1 to 3 PRACH is one group, the PRACH frequency receiving is adjusted near zero-frequency simultaneously; Suppress the interference outside PRACH channel simultaneously; Adopt sample one time at every M sampling point simultaneously; N sampled point carried out to FFT simultaneously; In the frequency-region signal of N sampled point from FFT, extract or 139 points at 839 simultaneously;

Taking 1 to 3 PRACH is one group, while suppressing the interference outside PRACH channel, further comprises simultaneously:

Centre by frequency spectrum shift to simultaneously treated PRACH frequency band;

Taking 1 to 3 PRACH is one group, adopts sample one time at every M sampling point simultaneously, comprising:

Do 6 times of extractions with 2 rank cic filter filtering simultaneously, obtain 4096 sampling points;

Wherein, further comprise:

Before carrying out random access detection, physical layer obtains the information of PRACH configuration information and uplink-downlink configuration from high level; According to the information acquisition targeting sequencing preamble code time-frequency mapping of PRACH configuration information and uplink-downlink configuration; Determine number, frequency translation position, M, N one of them or its combination of processing PRACH according to preamble code time-frequency mapping.

2. the method for claim 1, is characterized in that, uses low pass filter to suppress the interference outside PRACH channel.

3. method as claimed in claim 2, is characterized in that, described low pass filter is high-order limited impulse response FIR filter.

4. method as claimed in claim 2, it is characterized in that, described use low pass filter suppress interference outside PRACH channel in order in the time extracting at 839, ensure 24576 or in the time extracting at 139, ensure 4096 PRACH down-sampledly there is not the spectral aliasing that noise and physical uplink link sharing channel PUSCH bring.

5. the method for claim 1, is characterized in that, described M is in form Format0～3: 3,6,12 or 24, and in form Format4, be 1,2,4,8 or 16.

6. the method for claim 1, is characterized in that, described N is in Format0～3: 8192,4096,2048 or 1024, and in form Format4, be 4096,2048,1024,512 or 256.

7. the method for claim 1, is characterized in that, further comprises:

The FIR filter of the low order of connecting after cic filter, uses so that output narrowed width and passband gain are smooth.

8. method as claimed in claim 7, is characterized in that, the Frequency and Amplitude response of the FIR filter of described low order is the contrary of cic filter passband response.

9. the data demodulates equipment on PRACH, is characterized in that, comprising:

Frequency regulation block, for adjusting to zero-frequency both sides by the PRACH data spectrum receiving;

Filter module, for suppressing the interference outside PRACH channel;

Down-sampled module, for adopting sample one time at every M sampling point;

N point FFT module, for N sampled point carried out to FFT, M, N meet M*N=24576 or 4096;

839/139 extraction module, extracts or 139 points at 839 for the frequency-region signal of the sampled point of the N from FFT;

Described filter module and down-sampled module are cic filter;

Described frequency regulation block is further used for taking 1 to 3 PRACH and is one group, the PRACH data spectrum receiving is adjusted to zero-frequency both sides simultaneously; Described filter module is further used for taking 1 to 3 PRACH and is one group, suppresses the interference outside PRACH channel simultaneously; Described down-sampled module is further used for taking 1 to 3 PRACH and is one group, adopts sample one time at every M sampling point simultaneously; Described N point FFT module is further used for taking 1 to 3 PRACH and is one group, N sampled point is carried out to FFT simultaneously; Described 839/139 extraction module is further used for taking 1 to 3 PRACH and is one group, extracts or 139 points at 839 in the frequency-region signal of N sampled point from FFT simultaneously;

Described filter module is further used for being one group at taking 1 to 3 PRACH, while suppressing the interference outside PRACH channel, frequency spectrum shift is arrived to the centre of simultaneously treated PRACH frequency band simultaneously;

Described down-sampled module is further used for being one group at taking 1 to 3 PRACH, in the time that every M sampling point is adopted a sample, does 6 times of extractions with 2 rank cic filter filtering simultaneously simultaneously, obtains 4096 sampling points;

Wherein, further comprise:

Parameter determination module, obtains the information of PRACH configuration information and uplink-downlink configuration from high level for carry out random access in physical layer before detecting; According to the information acquisition preamble code time-frequency mapping of PRACH configuration information and uplink-downlink configuration; Determine number, frequency translation position, M, N one of them or its combination of processing PRACH according to preamble code time-frequency mapping.

10. equipment as claimed in claim 9, is characterized in that, described filter module is low pass filter.

11. equipment as claimed in claim 10, is characterized in that, described filter module is high order FIR filter.

12. equipment as claimed in claim 9, it is characterized in that, described filter module is further used in order to there is not the spectral aliasing that noise and PUSCH bring extracting ensure 24576 points 839 time or ensure 4096 PRACH in the time extracting at 139 down-sampled.

13. equipment as claimed in claim 9, is characterized in that, described down-sampled module is further used for adopting M in Format0～3 to be: 3,6,12 or 24, and in form Format4, be 1,2,4,8 or 16.

14. equipment as claimed in claim 9, it is characterized in that, described N point FFT module is further used for adopting N in Format0～3 to be: 8192,4096,2048 or 1024, and in form Format4, be 4096,2048,1024,512 or 256.

15. equipment as claimed in claim 9, is characterized in that, further comprise:

The FIR filter of low order, is connected on after cic filter, for making to export narrowed width and passband gain is smooth.

16. equipment as claimed in claim 15, is characterized in that, the Frequency and Amplitude response of the FIR filter of described low order is the contrary of cic filter passband response.