CN102223199A

CN102223199A - Mixed method and device for intermediate frequency signal

Info

Publication number: CN102223199A
Application number: CN2010101475404A
Authority: CN
Inventors: 熊军; 杨明; 顾伟
Original assignee: China Academy of Telecommunications Technology CATT
Current assignee: China Academy of Telecommunications Technology CATT; Datang Mobile Communications Equipment Co Ltd
Priority date: 2010-04-13
Filing date: 2010-04-13
Publication date: 2011-10-19
Anticipated expiration: 2030-04-13
Also published as: CN102223199B

Abstract

The invention relates to communication field and discloses a mixed transmitting method and device for intermediate frequency signals, aiming at realizing the aim of transmitting the LTE (Long Term Evolution)-TDD (Time Division Duplex) signal and the TD (Time Delay)-SCAMA (Synergistic Channel-Adaptive Multiple Access) signal at the same base station. The method comprises the following steps of determining the common shifting time of the TD-SCDMA signal and the LTE-TDD signal from uplink to downlink; within the common shifting time, carried out the interpolating operation respectively according to the TD-SCDMA signal and the LTE-TDD signal generated by physical layers; adjusting the intermediate frequency speed of the two signals to the same; superposing the TD-SCDMA signal and the LTE-TDD signal with the same intermediate frequency speed; and sending the superposed signal. Therefore, the mixed transmission of the TD-SCDMA signal and the LTE-TDD signal in the same base station is realized. The invention also discloses a base station.

Description

A kind of mixed method of intermediate-freuqncy signal and device

Technical field

The present invention relates to the communications field, particularly a kind of mixed method of intermediate-freuqncy signal and device.

Background technology

At present, at TD SDMA (Time Division-Synchronous Code DivisionMultiple Access, TD-SCDMA) Frame of transmission has adopted 4 layers of frame structure in the physical channel of system, comprising: superframe, radio frames, subframe, time slot/sign indicating number.Consult shown in Figure 1ly, the long 720ms of superframe is made up of 72 radio frames.A wireless frame length 10ms, it is divided into the subframe of two 5ms again.Each subframe is by 7 main time slots (length 675us) and 3 special time slots: downward guide time slot (DwPTS), up guide time slot (UpPTS) and protection time slot (GP) constitute, and in 7 main time slots, TS0 generally is used for descending, uses as Cell Broadcast CB; TS1 generally is used for up.

And in long-term advancing time division duplex (LTE-TDD) system, each radio frames is made up of 2 fields, and each field length is 5mS.Each field is made of 8 conventional time slots and DwPTS, GP, these 3 special time slots of UpPTS.Conventional slot length 0.5mS, DwPTS and UpPTS length are configurable, are 1mS but require DwPTS, GP, UpPTS total length.

Table 1

Consult shown in the table 1, in the LTE-TDD system, for each radio frames, " D " expression subframe is a downlink transmission, and " U " expression subframe is a uplink transmit, and " S " expression special subframe DwPTS, GP and UpPTS.Consult shown in the table 2, the numeral in the table 2 be the symbol numbers that subframe is occupied, in any case configuration, the final pairing total number of symbols of DWPTS+GP+UPPTS is 14 symbols, and is identical with the pairing total symbol quantity of conventional time slot.Wherein, subframe 0, subframe 5 and DwPTS are reserved as downlink transfer forever, and 1 subframe 1mS comprises 14 symbols.

Table 2

What TD-SCDMA system and LTE-TDD system adopted is respectively 3G technology and 4G technology, and therefore, at present, LTE-TDD signal and TD-SCDMA signal transmit and receive in base station separately respectively; Along with the development of technology,, need realize on same base station that the mixing of LTE-TDD signal and TD-SCDMA signal sends, and also not realize the above-mentioned purpose embodiment under the prior art in order to save system resource.

Summary of the invention

The embodiment of the invention provides a kind of mixed method and device of intermediate-freuqncy signal, in order to realize the emission in same base station of LTE-TDD signal and TD-SCDMA signal.

The embodiment that the embodiment of the invention provides is as follows:

A kind of mixing sending method of intermediate-freuqncy signal comprises:

Determine that TD-SCDMA signal and LTE-TDD signal are converted to descending common switching time by up;

In described common switching time, the TD-SCDMA signal and the LTE-TDD signal that produce at physical layer carry out the interpolation operation respectively, are adjusted to the intermediate frequency speed of two kinds of signals identical;

TD-SCDMA signal and LTE-TDD signal that intermediate frequency speed is identical superpose, and send the signal after the stack.

A kind of base station comprises:

First processing unit is used for determining that TD-SCDMA signal and LTE-TDD signal are converted to descending common switching time by up;

Second processing unit was used in described common switching time, and the TD-SCDMA signal and the LTE-TDD signal that produce at physical layer carry out the interpolation operation respectively, was adjusted to the intermediate frequency speed of two kinds of signals identical;

The 3rd processing unit is used for TD-SCDMA signal and LTE-TDD signal that intermediate frequency speed is identical and superposes, and sends the signal after the stack.

In the embodiment of the invention, in the base station, designed a kind of new mixing platform, by common switching time at TD-SCDMA signal and LTE-TDD signal, respectively these two kinds of signals are carried out the interpolation operation, the intermediate frequency speed of these two kinds of signals is increased to unified assigned rate, again the identical TD-SCDMA signal of intermediate frequency speed and LTE-TDD signal are superposeed and send, like this, just the mixing that has realized TD-SCDMA signal and LTE-TDD signal in same base station sends, simultaneously, also can be when the back signal that superposes be carried out filtering, by the flexible selection of broadband HB filter and arrowband HB filter, the signalling mirror of order looks like to be suppressed in the ideal range.

Description of drawings

Fig. 1 is a TD-SCDMA signal structure schematic diagram in the embodiment of the invention;

Fig. 2 is a LTE-TDD signal structure schematic diagram in the embodiment of the invention;

Fig. 3 A is a communication system architectural framework schematic diagram in the embodiment of the invention;

Fig. 3 B is a base station functions structural representation in the embodiment of the invention;

Fig. 4 be in the embodiment of the invention base station with TD-SCDMA signal and LTE-TDD signal mixing transmission flow figure;

Fig. 5 determines common switching time of the schematic diagram of TD-SCDMA signal and LTE-TDD signal for base station in the embodiment of the invention;

Fig. 6 mixes platform operation principle schematic diagram in the base station in the embodiment of the invention;

Fig. 7 be in the embodiment of the invention base station to the LTE-TDD signal filtering after the transition band spectrum diagram;

Fig. 8 be in the embodiment of the invention base station to the LTE-TDD signal filtering after the passband frequency spectrum schematic diagram;

Fig. 9 is the spectrum diagram behind the preferential filter of receiving terminal employing passband in the embodiment of the invention;

Figure 10 is the spectrum diagram behind the preferential filter of receiving terminal employing transition band in the embodiment of the invention;

Figure 11 is that the base station adopts integral multiple interpolation multiple to carry out interpolation operating principle schematic diagram in the embodiment of the invention;

Figure 12 is that the base station adopts decimal times interpolation multiple to carry out interpolation operating principle schematic diagram in the embodiment of the invention;

Figure 13 is P phase multiple filter interpolation operating principle figure in the embodiment of the invention;

Figure 14 is that receiving terminal adopts the integral multiple extracting multiple to carry out the extraction operation principle schematic in the embodiment of the invention;

Figure 15 is that receiving terminal adopts decimal times extracting multiple to carry out the extraction operation principle schematic in the embodiment of the invention;

Figure 16 is a P phase multiple filter extraction operation schematic diagram in the embodiment of the invention;

Figure 17 is the transition band frequency spectrum analogous diagram behind broadband HB filter and the arrowband HB filter filtering in the embodiment of the invention;

Figure 18 is the frequency spectrum analogous diagram that HB filter in broadband suppresses mirror image in the embodiment of the invention;

Figure 19 is the passband frequency spectrum analogous diagram behind broadband HB filter and the arrowband HB filter filtering in the embodiment of the invention;

Figure 20 is the frequency spectrum analogous diagram that HB filter in arrowband suppresses mirror image in the embodiment of the invention;

Figure 21 is the frequency spectrum analogous diagram behind the broadband HB filter filtering in the embodiment of the invention.

Embodiment

In order to realize the emission of LTE-TDD signal and TD-SCDMA signal, in the embodiment of the invention, determine that TD-SCDMA signal and LTE-TDD signal are converted to descending common switching time by up in same base station; In described common switching time, the TD-SCDMA signal and the LTE-TDD signal that produce at physical layer carry out the interpolation operation respectively, are adjusted to the intermediate frequency speed of two kinds of signals identical; TD-SCDMA signal and LTE-TDD signal that intermediate frequency speed is identical superpose, and send the signal after the stack.

Below in conjunction with accompanying drawing the preferred embodiment of the present invention is elaborated.

Consult shown in Fig. 3 A and the 3B, in the embodiment of the invention, communication system comprises several base stations, and the base station comprises first processing unit 10, second processing unit 11 and the 3rd processing unit 12, wherein,

First processing unit 10 is used for determining that TD-SCDMA signal and LTE-TDD signal are converted to descending common switching time by up;

Second processing unit 11 was used in described common switching time, and the TD-SCDMA signal and the LTE-TDD signal that produce at physical layer carry out the interpolation operation respectively, was adjusted to the intermediate frequency speed of two kinds of signals identical;

The 3rd processing unit 12 is used for TD-SCDMA signal and LTE-TDD signal that intermediate frequency speed is identical and superposes, and the signal after will superposeing mails to receiving terminal by communication interface.

Based on above-mentioned principle, to consult shown in Figure 4ly, in the embodiment of the invention, it is as follows that the base station realizes that TD-SCDMA signal and LTE-TDD signal mix the detailed process that sends:

Step 400: determine that TD-SCDMA signal and LTE-TDD signal are converted to descending common switching time by up.

In the practical application, because TD-SCDMA signal and LTE-TDD signal all are subframes of 5ms, and all are the TDD modes, and DWPTS in the special subframe of LTE-TDD signal, UPPTS and GP can dispose flexibly, promptly can revise flexibly according to the requirement of switching time; Therefore, the stack of TD-SCDMA signal and LTE-TDD signal can be realized two kinds of switching times that signal is common in the base station.

In the embodiment of the invention, for the sub-frame configuration scheme that realizes that TD-SCDMA signal and LTE-TDD signal coexisted on the point in switching time, including but not limited to following three kinds:

TD-SCDMA’s?5U2D?to?LTE-TDD’s?DSUUU+3:9:2

TD-SCDMA’s?3U4D?to?LTE-TDD’s?DSUUD+11:1:2/10:2:2

TD-SCDMA’s?2U5D?to?LTE-TDD’s?DSUDD+3:9:2

Consult shown in Figure 5, in the practical application, preferably, can be with the time started point alignment of the download of each signal emission, and with time started of the downlink of alignment as two kinds of switching times that signal is common, as:

First kind of sight: the time started of TD-SCDMA TS6 alignd with the time started of LTE-TDD TS0;

Second kind of sight: the TD-SCDMATS4 starting point was alignd with the time started of LTE-TDD TS8;

The third sight: the TD-SCDMATS3 starting point was alignd with the time started of LTE-TDD TS6.

After determining to put common switching time, just can adopt corresponding interpolation multiple, respectively TD-SCDMA signal and LTE-TDD signal are carried out the interpolation operation, make these two kinds of signals handle through different interpolations, on intermediate frequency speed, reach an agreement, like this, the signal of two systems just can be launched from a radio-frequency channel by stack.

Step 410: in described common switching time, the TD-SCDMA signal and the LTE-TDD signal that produce at physical layer carry out the interpolation operation respectively, are adjusted to the intermediate frequency speed of two kinds of signals identical.

In the present embodiment, the implementation method of step 410 is including but not limited to following two kinds:

1, adopts corresponding integral multiple interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal all is adjusted into first rate;

2, adopt corresponding integral multiple interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal all is adjusted into first rate, and, adopt corresponding integral multiple or decimal times interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal further is promoted to second speed by first rate.

Step 420: TD-SCDMA signal and LTE-TDD signal that intermediate frequency speed is identical superpose, and send the signal after the stack.

Based on the foregoing description, will make detailed description to the specific implementation of step 410 below.

Consult shown in Figure 6, from the mixing design of Platform scheme of base station as can be seen, TD-SCDMA signal and LTE-TDD signal are after the interpolation operation of step 410, can reach a plurality of common speed points, the screening conditions of these common rate points are: satisfy signals sampling speed (Fs) greater than signal bandwidth (FBW), satisfying the stack that to carry out TD-SCDMA signal and LTE-TDD signal on the common rate point of above-mentioned condition, but only choose suitable best mirror image is suppressed of speed point ability, the resource optimum.

As shown in Figure 6, in the embodiment of the invention, suppose that the TD-SCDMA that designs in the base station and LTE-TDD mixing platform receive the physical layer signal from TD-SCDMA carrier wave 1.28MHZ, the LTE-TDD signal of a 30.72MHZ, through multistage interpolation filtering, before carrying out the signal stack, the common rate point that TD-SCDMA signal and LTE-TDD signal can reach can have two, be respectively: first common speed point is 30.72MHZ, and second common speed point is 46.08MHZ; And after carrying out the signal stack, can also carry out the interpolation operation to superposed signal once more, thereby the 3rd the common speed point that obtains TD-SCDMA signal and LTE-TDD signal is 92.16MHZ.

As shown in Figure 6, in the embodiment of the invention, the initial rate of the LTE-TDD signal that physical layer produces is 30.72MHZ, and therefore, the base station only need adopt 1 times of interpolation multiple to carry out the interpolation operation, promptly the LTE-TDD signal can be maintained 30.72MHZ; Simultaneously, in order to suppress signal noise, when carrying out the interpolation operation, (Programm Finite Impulse Response, PFIR) the PFIR filter carries out filtering to the LTE-TDD signal can to adopt finite impulse response (FIR) able to programme.

With LTE-TDD signal and the merging of TD-SCDMA signal the time, be not leaked to for the frequency spectrum in the passband that makes carrying LTE-TDD signal in the multicarrier of carrying TD-SCDMA signal, the PFIR filter is had higher requirement, at the scene under the resource-constrained prerequisite of programmable gate array (Field Programmable Gate ArrayFPGA), preferably, can select the preferential PFIR filter of transition band, exchange the decay of transition band and precipitous for by some performances of sacrificing the PFIR passband.Consult Fig. 7 and shown in Figure 8, in the present embodiment, respectively to the base station adopt the preferential filter of transition band and passband preferential the effect of filter made emulation, wherein, what Fig. 7 showed is that the preferential filter of preferential filter of transition band and passband carries out filtered signal transition band spectrogram to the LTE-TDD signal respectively, and Fig. 8 displaying is that the preferential filter of preferential filter of transition band and passband carries out filtered signal passband spectrogram to LTE-TDD respectively.The performance parameter of two kinds of filters more as shown in table 3:

Table 3

Different filter type characteristics	Passband ripple (dBc)	Stopband attenuation (dBc)	Transition band	The scope of application
					The preferential filter of passband	0.002	50	Generally	Transition band is looser
The preferential filter of transition band	0.03	55	Steeper	Transition band is precipitous

With Fig. 8 is example, as can be seen from Figure 8, although the preferential filter ripple of transition band is much larger than the preferential filter of passband, but the passband ripple size of the preferential filter of transition band also has been lower than 0.03dBc, such ripple is very little to the influence of signal quality, therefore, the base station should preferentially adopt the preferential filter of transition band that the LTE-TDD signal is carried out filtering.

In like manner, the initial rate of TD-SCDMA signal only is 1.28MHZ, and is preferable, needs to adopt 24 times of interpolation multiples to carry out the interpolation operation, just the TD-SCDMA signal can be raised speed to 30.72MHZ; Simultaneously, preferable when carrying out the interpolation operation in order to suppress signal noise, also can adopt the preferential PFIR filter of transition band that the TD-SCDMA signal is carried out filtering, do not repeat them here.

Accordingly, in the embodiment of the invention, the receiving terminal of base station also needs to adopt the preferential filter of transition band that the LTE-TDD signal that receives from the base station is carried out filtering, because, if receiving terminal adopts the preferential filter of passband, then when receiving the LTE-TDD signal, can't be suppressed to contiguous TD-SCDMA signal under the transition band effectively, this is because the transition band of the PFIR filter of LTE-TDD signal is precipitous inadequately, wherein comprised the TD-SCDMA signal, so the spuious inhibition of LTE-TDD signal has only 30dBc, can't satisfy the requirement of radio frequency testing index.

Consult Fig. 9 and shown in Figure 10, in the present embodiment, respectively to receiving terminal adopt the preferential filter of transition band and passband preferential the effect of filter made emulation, wherein, what Fig. 9 showed is to adopt the preferential filter of passband that the LTE-TDD signal is carried out filtered spectrogram, and Figure 10 displaying is to adopt the preferential filter LTE-TDD signal of transition band to carry out filtered spectrogram.From Fig. 9 and 10 as can be seen, adopt the preferential filter of transition band to carry out filtering, can with the contiguous TD-SCDMA signal suppressing of LTE-TDD signal under transition band, suppressed near 50dbc, effect is better.

Based on the foregoing description, the base station is carried out the interpolation operation respectively at TD-SCDMA signal and LTE-TDD signal, the intermediate frequency speed of two kinds of signals is unified for behind the 30.72MHZ, can superpose at this speed two kinds of signals of naming a person for a particular job, and carry out subsequent treatment, also can carry out the interpolation operation once more to the intermediate frequency speed of two kinds of signals, make its intermediate frequency speed improve once more based on 30.72MHZ; In the present embodiment,, preferably, adopt the above-mentioned second way that the intermediate frequency speed of two kinds of signals is increased to second common speed point once more, as 46.08MHZ for the mirror image that makes the signal after the stack obtains good filtering.

When the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal is increased to 46.08MHZ once more by 30.72MHZ, can adopt the interpolation multiple of integral multiple, also can adopt the interpolation multiple of little several times, in the present embodiment, be that example describes in detail with the interpolation multiple of little several times.

Suppose to adopt 3/2 times interpolation multiple, then the implementation of interpolation operation is as follows:

Generally speaking, the processing of 3/2 times of interpolation filtering is at first to carry out 3 times of interpolations, is carrying out 2 times of extractions then, finishes decimal times interpolation by two steps and operates.In the present embodiment, adopt polyphase circuit to finish the operation of interpolation and extraction simultaneously, because the interpolation operation makes the speed of signal improve, so the interpolation multiple P＞Q, wherein, P is the output number of phases (also claiming the sub-number of phases) of circuit, and Q is the step-length when reading sub-phase output signal, and the essence of interpolation operation is exactly to be close to Q at P in heterogeneous to export one.

For example, P=3, Q=1 promptly is illustrated in 3 circuitry phases, and each circuit is all exported mutually; Consult shown in Figure 11ly, suppose that primary signal is a, b, c, d4 data are that all signals that produce are mutually all exported after 3 the interpolation operation by the interpolation multiple, promptly output signal is a1 successively, a2, a3, b1, b2, b3, c1, c2, c3 ....Input 4 numbers are exported 12 numbers like this.

Again for example, P=3, Q=2 then selectively exports based on step size Q=2, consult shown in Figure 12ly, suppose that primary signal is a, b, c, 4 data of d, be the operation of 3/2 interpolation by the interpolation multiple after, 4 number a are imported in the output again in the every interval of all signals that produce mutually like this, b, c, d, export 6 number a1, a3, b2, c1, c3, d2.So just in time finish the interpolation task of interpolation multiple 4*3/2=6.

Consult shown in Figure 13, in the embodiment of the invention, P=3, the structure of the polyphase interpolating filter of 9 filter coefficients as shown in the figure, in this kind structure, each sub-phase filter all uses multiplier separately to finish filter function, executed in parallel between each sub-phase filter, be applicable to that suitable signal rate is low, the processing that multiplier is many.

Polyphase interpolating filter is finished interpolation functions by using a high speed selector, and signal of every input just has the signal output of P road, and each all finishes filtering mutually under the situation of low speed.Reversing switch is the selection to the sub-filter dateout.For 3 times of interpolations, heterogeneous output is 1 phase in proper order, 2 phases, 3 phases, 1 phase, 2 phases, 3 phases, 1 phase, 2 phases.。。For 3/2 times of interpolation, then to isolate Q and export a phase mutually, above-mentioned output has just become 1 phase, 3 phases, 2 phases, 1 phase, 3 phases ... finish by the high speed reversing switch and just finished decimal times interpolation functions.

Through behind the aforesaid operations, the intermediate frequency speed of TD-SCDMA signal and LTE-SCDMA signal has just all reached 46.08MHZ, satisfies the requirement of overlap-add operation fully, can superpose to above-mentioned two kinds of signals at this speed point.

Correspondingly, when receiving terminal processing intermediate frequency speed is the intermediate-freuqncy signal of 46.08MHZ, need filtering extraction to transform to 30.72MHZ, extract

If integral multiple extracts, as P=1, Q=3, then Shu Ru data enter filter successively, and output is the stack of each sub-phase, consult Figure 14 as can be seen, import 6 signal a, b, c, d, e, f, and export 2 data (a+b+c), (d+e+f), make that output data quantity is 1/3 of input data.

If decimal doubly extracts, as P=2, Q=3 then superposes based on P=2, and the signal of being skipped is filled null value and got final product.Then consult shown in Figure 15ly, import 6 signal a, c, e, g, i, k, and export 4 signals (a+c), e, (g+i), k so just can make that output data quantity is 2/3 of input data, thereby finishes stack based on calculating still less.

Consulting shown in Figure 16ly, is example with the multiphase filter that extracts factor M=3,9 filter coefficient.

High-speed data sends to each height phase to the signal of input in the mode of time-division, and each height is finished filter function under the situation of low rate, and the mutually filtered signal of each height is finished the stack of data.Multiphase filtering extracts by using a high speed selector to finish extract function, and signal of every input, reversing switch switch and just switch a second son phase.

For example, for 1/3 times extraction operation, heterogeneous input sequence is 1 phase, 2 phases, 3 phases, 1 phase, 2 phases, 3 phases, 1 phase, 2 phases ...

And for above-mentioned 2/3 times of extraction operation, then switch according to step size Q=2, above-mentioned input has just become 1 phase, 3 phases, 2 phases, 1 phase, 3 phases ..., obviously, just finish by the switching of reversing switch and just to have finished decimal times extraction operation.

Further, in order to obtain the effect of better filtering superposed signal mirror image, in the embodiment of the invention, after with TD-SCDMA signal and the stack of LTE-SCDMA signal, before sending to receiving terminal, can carry out the interpolation operation to the signal after the stack once more, its intermediate frequency speed is increased to next common rate point again, as, 92.16MHZ.

In the present embodiment, the base station when carrying out signal after will superpose and raise speed again, can adopt platform adopt half-band filter (Halfband, when HB) filter realized that interpolation is operated, this was divided into two kinds of situations again:

Based on Fs/Fbw consider, Fs is the intermediate frequency speed after the superposed signal speed-raising, be 92.16MHZ, and Fbw is the bandwidth that intermediate-freuqncy signal takies, the HB filter is divided into broadband HB filter (being the mild filter of transition band) and arrowband HB filter (filter that transition band is precipitous) again.In order to realize better suppressing the effect of mirror image, in the embodiment of the invention, adopted arrowband HB filter in relative hour, when Fs/Fbw is big relatively, adopt broadband HB filter at Fs/Fbw, thereby can satisfy the requirement that system image suppresses, also take into account the requirement that resource is saved simultaneously.So-called Fs/Fbw is relatively little greatly also can be suppressed effect with mirror image and describes relatively with Fs/Fbw, as, after carrying out filtering with broadband HB filter earlier, if mirror image suppress to reach be provided with threshold value (as, 70dbc), then adopt broadband HB filter to carry out filtering, if mirror image suppress not reach be provided with threshold value (as, 70dbc), then use arrowband HB filter instead and carry out filtering.On the contrary, also can adopt arrowband HB filter to carry out filtering earlier, when undesirable, be changed to broadband filter again, not repeat them here.

Consult Figure 17, Figure 18 and shown in Figure 19, after adopting broadband HB filter and arrowband HB filter respectively intermediate-freuqncy signal to be carried out filtering, from the state of intermediate frequency signal transition band and pass band damping as can be seen, when Fs/Fbw is big relatively, if adopt broadband HB filter to carry out filtering, the side mirror picture suppresses to have only 33dBc, and this will have a strong impact on the radio-frequency (RF) index of communication system.Wherein, Figure 17 is the transition band frequency spectrum analogous diagram (decay of observation transition band) behind broadband HB filter and the arrowband HB filter filtering, Figure 18 is the frequency spectrum analogous diagram (decay of observation transition band) that broadband HB filter suppresses mirror image, and Figure 19 is the passband frequency spectrum analogous diagram (observation passband ripple) behind broadband HB filter and the arrowband HB filter filtering.Consult shown in Figure 19, the passband ripple of amplified broad band HB filter and arrowband HB filter as can be seen, though the passband ripple of arrowband HB filter is greater than the passband ripple of broadband HB filter, but ripple can be ignored the influence of communication system, therefore less than 0.005dBc, use arrowband HB filter this moment, can make mirror image obtain good restraining, concrete effect is consulted shown in Figure 20, and Figure 20 is the frequency spectrum analogous diagram (decay of observation transition band) that arrowband HB filter suppresses mirror image.

In the practical application, broadband HB filter order lacks 8 rank than the coefficient of arrowband HB filter coefficient, and simultaneously, the ripple of broadband HB filter is little, so broadband HB filter ripple is fit to be applied in the higher system of signal rate, and arrowband HB filter is fit to be applied in the lower system of signal speed.For example, be 184.32MHZ during in signal bandwidth to 92.16MHZ, adopt broadband HB filter, consult shown in Figure 21, along with

Increase and be twice, this moment, broadband HB filter surpassed 90dBc to the inhibition of mirror image, satisfied the user demand of system fully.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims

1. the mixing sending method of an intermediate-freuqncy signal is characterized in that, comprising:

Determine that TD SDMA TD-SCDMA signal and long-term advancing time division duplex LTE-TDD signal are converted to descending common switching time by up;

2. the method for claim 1 is characterized in that, be the time started of downlink described common switching time.

3. the method for claim 1 is characterized in that, describedly carries out the interpolation operation respectively at TD-SCDMA signal that receives and LTE-TDD signal, is adjusted to identically with the intermediate frequency speed with two kinds of signals, comprising:

Adopt corresponding integral multiple interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal all is adjusted into first rate;

Perhaps

Adopt corresponding integral multiple interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal all is adjusted into first rate, and, adopt corresponding integral multiple or decimal times interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal further is promoted to second speed by first rate.

4. method as claimed in claim 3 is characterized in that, when carrying out the interpolation operation at the LTE-TDD signal, adopts the preferential filter of transition band.

5. method as claimed in claim 3 is characterized in that, adopts corresponding integral multiple interpolation multiple or decimal times interpolation multiple, and the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal further is promoted to second speed by first rate, comprising:

Adopt the multiple filter of P phase that TD-SCDMA signal and the LTE-TDD signal that receives carried out interpolation filtering, and adopt step-length Q to read filtered output signal, wherein, P is the output number of phases of described multiple filter, Q is the step-length when reading output signal, and the ratio of P and Q is the interpolation multiple of integral multiple or the interpolation multiple of little several times.

6. as each described method of claim 1-5, it is characterized in that, comprise: TD-SCDMA signal and LTE-TDD signal that intermediate frequency speed is identical superpose, signal after will superposeing comprises before mailing to receiving terminal: adopt the intermediate frequency speed of the signal after the HB filter will superpose further to be increased to third speed.

7. method as claimed in claim 6 is characterized in that, when the intermediate frequency speed of the signal after employing partly will superpose with the HB filter further is increased to third speed, comprising:

The signalling mirror picture of signal behind the HB filter filtering of broadband that calculates after superposeing suppresses parameter, if suppressing parameter, described signalling mirror picture reaches setting threshold, signal after then adopting broadband HB filter to stack carries out the interpolation operation, do not reach setting threshold if described signalling mirror picture suppresses parameter, then adopt arrowband HB filter that the signal after superposeing is carried out the interpolation operation.

8. a base station is characterized in that, comprising:

First processing unit is used for determining that TD SDMA TD-SCDMA signal and long-term advancing time division duplex LTE-TDD signal are converted to descending common switching time by up;

9. base station as claimed in claim 8, it is characterized in that, described second processing unit carries out the interpolation operation respectively at TD-SCDMA signal that receives and LTE-TDD signal, be adjusted to when identical with intermediate frequency speed two kinds of signals, adopt corresponding integral multiple interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal all is adjusted into first rate, perhaps, adopt corresponding integral multiple interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal all is adjusted into first rate, and, adopt corresponding integral multiple or decimal times interpolation multiple, the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal further is promoted to second speed by first rate.

10. base station as claimed in claim 9 is characterized in that, when described second processing unit carries out the interpolation operation at the T LTE-TDD signal that receives, adopts the preferential filter of transition band.

11. base station as claimed in claim 9, it is characterized in that, described second processing unit adopts corresponding integral multiple interpolation multiple or decimal times interpolation multiple, when the intermediate frequency speed of TD-SCDMA signal and LTE-TDD signal further is promoted to second speed by first rate, adopt the multiple filter of P phase that TD-SCDMA signal and the LTE-TDD signal that receives carried out interpolation filtering, and adopt step-length Q to read filtered output signal, wherein, P is the output number of phases of described multiple filter, Q is the step-length when reading output signal, and the ratio of P and Q is the interpolation multiple of integral multiple or the interpolation multiple of little several times.

12. as each described base station of claim 8-11, it is characterized in that, TD-SCDMA signal and LTE-TDD signal that described the 3rd processing unit is identical with intermediate frequency speed superpose, before signal after will superposeing mails to receiving terminal, adopt the intermediate frequency speed of the signal after the HB filter will superpose further to be increased to third speed.

13. base station as claimed in claim 12, it is characterized in that, when described the 3rd processing unit adopts the intermediate frequency speed of the signal after the HB filter will superpose further to be increased to third speed, the signalling mirror picture of signal behind the HB filter filtering of broadband that calculates after superposeing suppresses parameter, if suppressing parameter, described signalling mirror picture reaches setting threshold, signal after then adopting broadband HB filter to stack carries out the interpolation operation, do not reach setting threshold if described signalling mirror picture suppresses parameter, then adopt arrowband HB filter that the signal after superposeing is carried out the interpolation operation.