CN1284345C - System and method for peak power reduction in spread spectrum communications systems - Google Patents

Abstract

A system and method for signal peak reduction in a spread spectrum communication system of the type including a filter for limiting signal bandwidth of symbols transmitted from the system. A signal peak reduction un it (122) is provided before the filter (126) the includes a filter predictor (146) that predicts the effect of that filter on input symbols by using filter coefficient values corresponding to the filter impulse response function. Input symbols that are predicted to cause the output signal to exceed a predetermined peak limit value are adjusted. Several examples of suitable algorithms for calculating the necessary peak reduction to be applied to the input symbols are disclosed. The peak reduction unit provides adjusted symbols to the filter for processing and communication system output.

Description

In spread spectrum communication system, reduce the system and method for peak power

Technical field

The present invention relates to code division multiple address communication system and relevant method of operation.More specifically, the method that the present invention relates to cellular communication system and signal handling equipment and in cellular communication system, adopt.

Background technology

The transmission wireless communication system of employing between base station and a plurality of mobile subscriber is the critical component of modern communications infrastructure.(, this wireless communication system being called " honeycomb " communication system at this) for special frequency channel brief and that term " honeycomb " is not restricted to the communication system of particular type or is associated with this term sometimes.These cellular systems are placed oneself in the midst of under the ever-increasing performance requirement, and to available equipment, especially the ability of honeycomb base station device has increased the weight of burden.These ever-increasing performance requirements be since in given cellular zone ever-increasing number of users and cause for the bandwidth requirement of given channel.Yes understands easily for ever-increasing cellular telephone subscribers number, and because this trend of cellular convenience is impossible slack-off.Second kind of consideration is owing to caused by the continuous increase of the function type that cell phone system provided to a great extent, inserts and pass through other forms of the data passes of cell phone system as the internet.These consider to have caused for more channel in offering the usable spectrum of cellular phone carrier and to the needs of the bigger bandwidth of each channel.

The conventional method that makes channel as much as possible adapt to available spectrum is that each channel is placed in the narrow-band.Yet, for fear of disturbing significantly between each cellular system users, each channel must be fully on frequency away from.Frequency band for given channel is narrow more, and is also more little for the available bandwidth of particular channel.

It is CDMA bandspread communication that the another kind of method of maximum channel number is provided in given frequency spectrum, and this is used in increasing Digital Cellular System.When digital information by when a place sends to another place, before transmission, data bit is transformed into data symbol.The bandwidth of the signal that is sent is the function to each symbolic number that data bit sent that is sent out.In CDMA bandspread communication, the symbol that is sent is more than the data bit that will send.Specifically be to send a plurality of symbol codes for each data bit that will send.The receiver of knowing this code recovers the data bit that is sent out with the signal decoding that is sent.By the unique code of suitable selection, many users can not have to communicate by letter in identical bandwidth intrusively, are quadratures because make each channel by coding.In the CDMA spread spectrum cellular system, in typical case, select spreading code, will expand on frequency spectrum from the data of each channel than broad, yes in for given honeycomb supplier available spectrum scope.Do the interference that makes interchannel like this for minimum, make in the usable spectrum number of channel for maximum.At present, there are two kinds of standards that relate to CDMA cellular communication system.Usually these standards are called CDMA and WCDMA for code division multiple access and Wideband Code Division Multiple Access (WCDMA).Owing to highly effectively utilize available spectrum, CDMA and WCDMA are used as the selection scheme that adapts to ever-increasing honeycomb purposes more and more.

Yet, when reality realizes spread spectrum cellular system, owing to there is a problem in multiuser channel combination results spread-spectrum signal.This can be by understanding with reference to figure 1, and Fig. 1 is illustrated in the generation of spread-spectrum signal in a kind of typical prior art cellular basestation embodiment.As shown in fig. 1, in a kind of spread spectrum system, code multiplex signal generator 10 receives a plurality of data channel D, for example, and the number n corresponding with the number of users that can be received.Multiply by the orthogonal code of a separation by incoming symbol, for each communication channel produces symbol sebolic addressing to each channel.The amplitude of each channel can have difference according to the needs of each channel power.Being produced the multiplexed symbol sebolic addressing of single code (has homophase and quadrature component, V in Fig. 1 mutually with each symbol sebolic addressing then ₁And V ₂).Then the multiplexed symbol sebolic addressing of this code by a filter 20 to produce desirable output signal.This filter plays a part crucial, because it is forced " frequency spectrum mask " (a spectral mask) on symbol sebolic addressing, guarantees that broadcast singal remains in the frequency spectrum of distributing to cellular carriers.Do not produce noise in accordance with running counter in federal regulation and the adjacent frequency band at given carrier wave in these restrictions on the spectrum allocation may.Then this output signal is offered digital to analog converter 30, obtain the analog signal of in modulator 40, mixing with carrier signal.The RF signal of gained is offered RF power amplifier 50 and plays to the phone user.

Problem is from the code multiplexer 10 of Fig. 1 a plurality of symbol sebolic addressing combinations being begun.Because with the combination of many independent symbol sebolic addressings, will depend on the amplitude of each symbol of combination from the peak power of the resultant signal of filter output.It is possible on statistics that the symbol of each channel produces very large composite symbol peak value with addition.Although is not common situation, in the whole system design, must adapt to these very large symbol peaks on statistics.In whole system, adapt to these big symbol peaks and produce problem aspect the actual enforcement.For example, from the signal of filter output, exist potential very large peak value needs for digital-to-analog converter to use a kind of very high-resolution digital-to-analog converter.This has just increased the cost and the complexity of whole system.

Another problem relevant with very large-signal peak value potential in the CDMA spread spectrum system relates to by the RF power amplifier provides difficulty to the signal linear amplification.In cellular system, it is very important providing linear amplification to broadcast singal.This is can cause signal distortion and produce the spectral sideband that can disturb other cellular band because of the non-linear amplification to signal.Because cellular band is strictly controlled, must design cellular system carefully, make and avoid this noise outside the frequency range of being distributed to produce.Therefore, it is necessary amplifying at the RF of cellular basestation neutral line.Yet, operate in its range of linearity in order to make amplifier, need amplifier to operate in the quite low power mode.If random peaks big in the signal will and still keep it to operate in the linear condition by a kind of like this amplifier adaptation, just need the RF amplifier of higher-wattage.High power, high-quality RF amplifier is very expensive, so just to the very big cost of whole base station system increase.

Therefore the problem of big random peaks is a great problem in reality enforcement spread spectrum cellular communications system in the signal.

The importance of big random signal peak problem is familiar with in the prior art to some extent, and the solution of this problem was attempted.For example, a kind of method that addresses this problem is described in the U.S. Patent No. 6,009,090 of investing Oishi etc., figure 2 illustrates the method for U.S. Patent No. 6009090.Signal peak is suppressed the signal that unit 60 is placed on code multiplexer 10 back that each symbol sebolic addressing is added together to be produced in the path.This signal peak suppresses the unit makes comparisons multiplexed symbol and maximum permissible value, directly those symbols that surpass maximum permissible value is clipped then.Though this peak value suppresses the problem that the unit has solved big symbol, yet it does not remove all large-signal peak values that must be handled by D/A converter and power amplifier.In addition, when a symbol is cut off, send less-than-ideal symbol, this will increase the mistake of communication.By considering that meticulously signal peak suppresses the influence of unit to these symbols when these symbols produce the path by signal continuously, be appreciated that this point.

As shown in Figure 2, the repressed symbol of peak value leaves peak value to be suppressed after the unit, and they are by a filter 20.Filter 20 can be represented with an impulse response function.A kind of typical spread spectrum pulse response function is shown in (WCDMA, root raised cosine, α=0.22) among Fig. 3.When symbol passed through filter, the impulse response of filter was exerted one's influence to the multiplexed symbol of each code.Filter impulse response can increase or reduce peak value on mark space to the influence of symbol, and can produce new peak value between symbol time.More specifically, Fig. 4 illustrates filter output peak value and can how to be different from the incoming symbol peak value.Fig. 4 demonstrates the filter output that the incoming symbol by two amplitudes 1 in succession causes.Two incoming symbols are created in the filter impulse response function of representing with solid line and dotted line among Fig. 4 in filter output.The combination (but in order to illustrate that this addition is not implemented easily in Fig. 4) of these two kinds of responses is exported thereby will be to real filter.In its maximum, another is then a little a bit negative in 0, one impulse response of symbol time.Therefore for this situation, signal output will be lower than incoming symbol amplitude on the symbol time 0.(if second symbol has been negative rather than just, and signal is with the incoming symbol on the is-greater-than symbol time 0).When two filter response additions produce about 1.2 array output, output signal will reach maximum at symbol time 0.5 (intersymbol).In a kind of output signal of reality, the influence of other symbols that occur simultaneously in filter will strengthen these effects.

Fig. 5 A and 5B with explain a given incoming symbol and in symbol sebolic addressing the symbol before and after this symbol, when these symbols during by filter, the scope of the output signal value that on statistics, can produce.Fig. 5 A and 5B are with explaining the complex vector located figure of an incoming symbol conduct from a vector (homophase and quadrature signal component) of complex number plane.Fig. 5 A illustrates the incoming symbol just over desirable peak value limit value (dotting).In Fig. 5 B, incoming symbol is accurately to drop on the limit value line.Filtered output signal is a function of incoming symbol and filter impulse response function.As from the discussion of Fig. 4 clearly, the output signal peak value will be distinguished randomly in the incoming symbol peak value, because difference is because to leading and cause in the filter response of the random mark of this symbol subsequently in time.Represent with the solid line circle that indicates " the filter output of prediction " in the drawings on this stochastic effects statistics.

When filter was considered to the influence of the symbol sebolic addressing by filter, the result who suppresses the unit with the signal peak that is marked with the `090 patent was changed significantly.For example, suppose the incoming symbol shown in Fig. 5 A, the `090 patent will be carried out the peak value inhibition to this symbol all the time when it surpasses limit value.Thereby introduced some distortion by this process all the time.Yet, be filtered output by the actual value of D/A conversion and RF amplification, on statistics, represent with a circle.Just as can be seen, some the time, filtered value will not need limit value in limit value the inside.On the other hand, some the time, filtered value will be above limit value, greater than incoming symbol.Even being intercepted, incoming symbol is limit value, also will be by peak value adjusting inadequately.In the example of Fig. 5 B, incoming symbol is no more than limit value successively, and all these symbols will pass through insusceptibly in the method for `090 patent.Yet as output circle filtered from Fig. 5 B was understandable, the influence of filter was that output signal will surpass limit value in fact widely.Therefore, for this situation, adopt `090 patent unit not solve the signal peak problem.Thereby more than indicate the `090 patent method not only unnecessary distortion is introduced peak value and is suppressed in the unnecessary signal, and do not eliminate many peak values unnecessary in output signal fully, this will design the problem of solution just.

Though do not discuss in above-indicated patent, a kind of alternative method can directly suppress peak value the downstream that the unit is placed on the filter 20 shown in Fig. 2.Yet this also introduces a problem, will make the filter output signal distortion inevitably because peak value suppresses the existence of unit.This extends to the outer spectral noise of spectral mask that this filter is designed to keep with generation.Such as noted above, the spectral mask that produces by the filtering to signal is critical in cellular system, may run counter to federal regulations potentially because exceed the distribution of frequency spectrum.

Therefore, no matter peak value suppresses the unit and is placed on before the filter or behind the filter, and is very clear, and spike problem is unaccommodated fully to a solution for solving in the output signal greatly like this, such solution or do not eliminate peak value is perhaps introduced problem of equal importance.Thereby a kind of like this method is inoperable in the application of real world.

Therefore, will be understood that, at present for the system and method that the CDMA spread spectrum cellular transmission is provided exist a kind of avoid above-indicated large-signal spike problem with incident with so big peak value RF is amplified the constraint relevant with digital to analog conversion and becomes this locality needs.And, will be understood that, there be a kind of so system not being introduced great additional new problem and can not had undue cost or the needs of the system and method that the mode of other enforcement complexity is implemented.

Summary of the invention

The invention provides a kind of above-indicated problem that is used to overcome, reduce the system and method for signal peak power in the CDMA bandspread communication system.And the present invention is with the spectral property of ungreat change signal, and the mode that signal is introduced great undesirable distortion and whole system do not increased great complexity does not provide a kind of like this system and method.

In first aspect, the invention provides a kind of reception by the output of this system, the spread spectrum communication system of the spread symbol corresponding with the mask data channel of a plurality of combinations.Communication system comprises that one is used for before exporting from system the symbol filter filtering.Reduce the unit in the filter prerequisite for a peak value, be connected between input spread symbol source and the filter.Peak value reduces the unit and receives the input spread symbol from the spread symbol source and utilize the known filter coefficient value corresponding with the filter impulse response function as input, and predictive filter is to the influence of symbol.Peak value reduction unit is only carried out peak values reduction to predicted those spread symbol that make filter output surpass predetermined peak value limit value and is handled.Then, peak value reduces the unit provides the symbol of having handled to export for filtering with by communication system to filter.

Peak value reduces the unit preferably to the spread symbol flow operation of sampled before filtering (up sample).Up-sampling does not change the time between the spread symbol by increasing character rate at the symbol that inserts zero amplitude between the spread symbol.By inserting these zero amplitude symbols the symbol bandwidth that obtains is increased.The increase of this symbol bandwidth has produced the space for the passband and the stopband of filter.Peak value reduction unit is preferably in up-sampling and was performed operation in the past, but also can operate later at up-sampling.

When up-sampling is operated in the past, peak value reduces the unit preferably to be adopted from the coefficient of filter impulse response periodicity of function sampling.For example, if the up-sampling process increases the symbol of three zero amplitudes between spread symbol, will there be four different periodic samplings available.Time between the sample of being got be with spread symbol between time identical.The periodic samples of this filter impulse response is used to produce a filter prediction of output device.To predict according to the timing of the periodic samples of being got.At least these periodic samplings should regularly and in intersymbol (inter-symbol) timing obtain at (on-symbol) on the symbol.Peak value reduction unit will comprise according to the timing on the symbol then, and the first order of peak value reduction and the second level that provides peak value to reduce according to intersymbol timing are provided.Another kind of way is that a kind of multistage embodiment can be provided.A kind of so multistage embodiment can adopt multistage peak value to reduce and handle, and every grade corresponding to a kind of different periodic filter sample regularly, implements with series arrangement or parellel arranged mode.Every grade of peak value reduces the unit and can further comprise a feedback loop, and the peak value reduction that turns back to filter fallout predictor value is provided.Also used in interim mode because peak value reduces, the peak power of duplicating reduces level can provide further peak factor to improve.When handling by the serial or parallel mode, these replication orders should be followed a whole set of every other periodic samples.

When behind up-sampling, operating, directly obtain coefficient from the filter impulse response function by up-sampling speed.These coefficients are used to produce a filter prediction of output device then.To on up-sampling speed, finish the filter prediction of output.To carry out peak value from these predictions reduces.This method is not preferred for some application and/or some impulse response function.When on the up-sampling rate, operating, can provide peak value to reduce to the null value symbol that during up-sampling, adds.Digital communication system is used to making the transmission and the receiving filter of intersymbol interference minimal design as CDMA and WCDMA.In order to keep minimum intersymbol interference in communication period, the null value symbol that adds during up-sampling must remain null value.Operation on up-sampling speed also need be carried out processing on higher rate.Generally, processing speed is high more, and the cost of processing unit is expensive more.Yet have some application like this, these costs are inessential and do not need to be considered that the processing behind the up-sampling is preferred.

More specifically, in a kind of detailed embodiment, spread spectrum communication system comprises that a peak value reduces the unit, reduces counting circuit comprising a filter prediction of output device and a peak value, and the peak value reduction is based on the filter prediction of output and predetermined filter output limit value.Peak value reduces the unit and preferably also comprises a combiner, be used for calculate peak value reduction value to be combined to filter prediction of output device be the spread symbol at center.Like this, peak value reduces the unit with half of spread symbol filtering wave by prolonging time device fallout predictor length, and in the mode of time synchronized, provides peak value to reduce on the basis of symbol one by one and proofreaies and correct.A multiplier circuit and the gain of peak value reduction value, the symbol that provides peak value to be conditioned when the spread symbol with time synchronized multiplies each other can be provided combiner.Another kind of way is that an add circuit and peak value reduction value vector, the symbol that provides peak value to be conditioned when being added to spread symbol can be provided combiner.

In one aspect of the method, the invention provides a kind of system that is used to reduce peak signal value, this system is adapted to for using in the communication system that comprises a filter, and this filter is in the filtering that provided in the past from described system output signal symbol.The system that is used to reduce peak signal value comprises a filter predictor device, be used for being received spread symbol in the past by described filter filtering, and predict the influence of described filtering to described symbol, with the device of linking the filter predictor device, be used to be reduced in and stand the predicted spread symbol peak value that surpasses the peak value limit value after the described filtering.Filter in communication system can be represented by predetermined impulse response function, and the filter predictor device preferably includes the device that is used to receive the filter coefficient corresponding with impulse response function on a plurality of periodic sampled points.

In a kind of preferred embodiment, the device that is used for the receiving filter coefficient at least in timing on the symbol and intersymbol timing from filter impulse response function receiving filter coefficient.Filter coefficient also can be provided on the time at additional impulse function, is periodically sampled from impulse response function with character rate.In addition, any or all of symbol coefficient time can be repeated, so that estimate because peak value reduces the peak value reduction error that the causality character of processing causes.

In yet another aspect, the invention provides a kind of method that is used for reducing peak signal value at the spread spectrum communication system that comprises filter type.This filter can be represented with an impulse response function, in the filtering that provided in the past from described system output signal symbol.This method is included in by described filter filtering and received spread symbol in the past, and predictive filtering is to the influence of symbol.This method further comprises regulates those predicted values of symbol that makes filter output surpass the peak value limit value.

In a kind of advantageous applications of the present invention, the present invention can be in a kind of spread spectrum cellular communications system, as being implemented in CDMA or the WCDMA system.For example, the present invention can be implemented in a kind of like this base station of spread spectrum cellular application.In a kind of like this application, avoided the problem of the linear RF amplifier of big peak value, and can adopt the RF amplifier that has reduced cost.Needs to expensive D/A converter are also avoided.And, finished in the past that peak value reduce to be eliminated the generation of sideband and to possible the running counter to of spectrum allocation may rule in filtering.

Will be understood that other features and advantages of the present invention by consulting following detailed description of the present invention.

Description of drawings

Fig. 1 is a kind of block schematic of prior art spread spectrum communication system.

Fig. 2 is a kind of block schematic that adopts signal peak to suppress the prior art spread spectrum communication system of unit.

Fig. 3 is a kind of impulse response function sketch that is used for prior art spread spectrum communication system filter.

Fig. 4 be illustrate two in succession symbol and in the prior art spread spectrum communication system their filter response function.

Fig. 5 A and 5B are with explaining in a kind of prior art spread spectrum communication system filtering to the complex vector located figure of the influence of consecutive symbols sequence arbitrarily.

Fig. 6 is with the block schematic that explains according to a kind of spread spectrum communication system that the invention provides the peak value reduction.

Fig. 7 is the block schematic that reduces a kind of preferred embodiment in unit as the peak value of key diagram 6.

Fig. 8 is illustrated on the symbol at interval and intersymbol is gone up a kind of filter impulse response functional arrangement of filter coefficient at interval.

Fig. 9 is with explaining the block schematic that peak value reduces a kind of preferred embodiment of process.

Figure 10 is with explaining the block schematic that the peak value that utilizes feedback reduces a kind of alternative embodiment of process.

Figure 11 reduces the unit block schematic with a kind of multistage peak value that explains according to a kind of alternative embodiment of the present invention.

Figure 12-the 21st is illustrated in the filter impulse response functional arrangement that a plurality of different periodicity regularly go up filter coefficient, and according to the present invention, the multistage peak value of Figure 11 reduces the unit can adopt these filter coefficients.

Figure 22 illustrates according to the present invention to adopt the parallel a kind of multistage peak value reduction unit block schematic that peak value reduces level of implementing.

Figure 23 illustrates according to the present invention to adopt the parallel a kind of alternative multistage peak value reduction unit block schematic that peak value reduces level of implementing.

Figure 24 illustrates the block schematic that reduces a peak value reduction level in the unit according to the multistage peak value of Figure 22 of the present invention and 23.

Figure 25 illustrates the complex vector located figure that reduces the vector that adopts in the algorithm according to a kind of peak value of the present invention.

Figure 26 illustrates the complex vector located figure that reduces the vector that adopts in the algorithm according to a kind of alternative peak value of the present invention.

Figure 27 illustrates according to the present invention for the predictive filter output valve of the example of a specific incoming symbol value and the plural number figure of peak value reduction operation.

Figure 28 illustrates according to predictive filter output valve and the peak value of the present invention on different incoming symbol values to reduce the plural number figure that operates.

Figure 29 illustrates the detailed embodiment block schematic that reduces one-level in the unit according to peak value of the present invention.

Figure 30 illustrates the detailed embodiment block schematic that the peak value that reduces algorithm according to a kind of approximate peak value of the invention process reduces one-level in the unit.

Figure 31 illustrates according to the present invention to adopt the peak value of feedback to reduce the detailed embodiment block schematic of one-level in the unit.

Figure 32 illustrates a kind of alternative embodiment block schematic that reduces one-level in the unit according to peak value of the present invention.

Figure 33 illustrates according to the present invention to utilize the alternate embodiment block schematic shown in when feedback Figure 32.

Figure 34 illustrates a kind of detailed embodiment block schematic that reduces one-level in the unit according to the peak value of the present invention's operation on the intersymbol interval.

Figure 35 illustrates the detailed embodiment block diagram shown in the Figure 34 that utilizes feedback.

Figure 36 A and 36B illustrate a kind of multistage peak value that adopts the parallel enforcement peak value shown in Figure 23 to reduce level according to the present invention to reduce unit detailed embodiment block schematic.

Embodiment

With reference to figure 6, a kind of spread spectrum communication system preferred embodiment that adopts peak power to reduce according to the present invention is shown.Though shown spread spectrum communication system can be at a kind of wireless cellular network, as implementing in WCDMA or the CDMA net, and these systems provide a kind of preferred application of the present invention, should be realized that for of the present invention other to use and environment also is possible.

As shown in the figure, quantity is the data input that a plurality of channels of N are provided as the system that enters.Data channel can comprise for example audio data in digital cellular is used, and perhaps can comprise the data of hope by any other form of communication system transmission.Data in each channel provide symbols streams by a data-sign changer 100 from the data bit stream of importing then.Various different symbolic coding scheme can be used to provide symbols streams (QPSK or " Quadrature Phase Shift Keying " are used in the WCDMA) from the data bit stream of input.(meaning that in Fig. 6 after data-sign changer, all processing paths are plural numbers, comprise homophase and quadrature component).Then, the symbols streams in each channel is provided for a blender 110, therein the stream of the incoming symbol in each channel is mixed with the spreading code that is provided by spreading code circuit 112.For example, in spread spectrum cellular communications system, can adopt a kind of Walsh sign indicating number.Each channel receives a unique quadrature spread code, allows to utilize a kind of spreading code that goes of coupling to recover each channel at receiver end.With the combination of unique spreading code after each channel can be provided for another blender 114 once more, therein with signal in each channel and scramble code combination from scramble labeling scheme 116.The scramble code is used in the identification that supplies cell position in the cellular application.The scramble code is used in the cellular communication system in typical case, but also can be dispensed in other the application.The output of each channel is provided for add circuit 120 then, will from each channel each symbols streams combination and they are combined in the single output symbol stream (in two kinds of complex orthogonal phase places each).

Because N channel is combined in together in add circuit 120, such as in the above background parts discussion cross like that, have the possibility of the very large symbol peaks of generation.The invention provides a kind of peak value and reduce unit 122, reduction or elimination are from the signal peak of filter 126 outputs, and these peak values will be above the given peak signal max power level of choosing for the particular communication system applies.As further illustrating among Fig. 6, the output that peak value reduces unit 122 is provided for a up-sampling circuit 124, character rate is transformed to satisfies or surpass frequency for the bandwidth requirement of interested frequency range.The up-sampling process will be directly with the zero insertion symbols streams in typical case, makes signal flow can be operated in desirable higher clock rate to satisfy or to surpass the needs of bandwidth.Therefore, will insert M individual zero in symbols streams for each incoming symbol, wherein M is an integer for providing desirable up conversion to choose.Integer M will be 1 or more at least in typical case.The signal flow of up-sampling is provided for a filter 126 then.The operation of up-sampling circuit 124 can be merged in the operation of filter 126 rather than in the circuit that separates and carry out in some cases.Filter output is provided for a digital-to-analog converter 128 so that analog signal to be provided.This analog signal will be made up of homophase that this details is not illustrated and quadrature component.This analog signal is mixed with RF carrier wave from RF source 136 in blender 134, and the signal of RF modulation is provided for a RF amplifier 130 then, then, for example in the application of radio honeycomb communication base station, is provided for a RF transmitter 132.It is a kind of to the unshowned quadrature up conversion of this details frequency mixer that blender 134 is actually in this application.As to those skilled in the art be well-known, can be selectively be transformed into the real signal of the base band centre frequency of offset from zero Hz from the signal of filter output from homophase and orthogonal signalling.If this is done, the D/A converter can be used to produce real intermediate frequency output, can utilize a kind of simple standard mixer mixing to become the RF frequency then.

Such as in the above background parts discussion crosses, the filtering operation that is provided by filter 126 is extremely important in the application of many employing spread spectrum communications.Particularly, in cellular communication system, because signal such filtering in the frequency band of predesignating that must keep being sent is critical.Filter 126 also will have great influence to the signal peak that is produced by symbols streams, therefore can influence any peak value of being implemented significantly and reduce before such filtering.

Peak value reduces unit 122 by according to symbols streams input predictive filter output 126, according to the signal peak of being predicted after the filtering symbol implementation peak value is reduced then and handles.This filter predicted operation that peak value reduces unit 122 can very accurately be realized, because the impulse response function of filter 126 is in advance known.Therefore, filter can be by a kind of circuit any desirable accuracy that calculates to a nicety to the influence of any given symbols streams, this circuit has as the filter coefficient to the desired number of the input of this circuit, so that analog filter impulse response function suitably.These filter coefficients are added on the incoming symbol stream, and analog filter produces the filtering output stream of prediction to the influence of incoming symbol stream.Yu Ce filtering output stream is stood peak value and reduce to be calculated then, determines whether that the filter output stream predicted will be above the signal peak limit value, if, just need correction.If limit value is exceeded, then Shi Ji symbols streams is stood peak value and reduce to be handled, and the signal peak with gained on the basis of symbol one by one is reduced to desirable limit value.

In this way, have only the peak value that needs to reduce and be performed, minimum distortion is introduced into signal.The precision that peak value reduce to be handled and the precision of filter forecasting process can reduce the speed of circuit and complexity and the balance of the cost that is associated is chosen according to peak value.Yet in great majority were used, filter prediction processing and peak value reduce to be handled and can be properly implemented and very not big to whole system increase complexity or cost.

With reference to figure 7 and 8, the preferred embodiment that a kind of peak value reduces unit 122 is shown.More specifically, a kind of peak value shown in Figure 7 reduces the block schematic of unit 122, reduces the exemplary filter coefficient that adopts in the circuit 122 with explaining at peak value in Fig. 8, and a kind of impulse response function of exemplary filter is shown.As shown in the figure, peak value reduces unit 122 and preferably includes two-stage 140,142, corresponds respectively to the interval on symbol, t=0 and intersymbol interval, and the peak value on the t=0.5 reduces.The order of this two-stage is random.About Fig. 6 discussed, symbols streams is in typical case by sampled before the filter 126 as above.Therefore, additional sampled point will be added in the symbol sebolic addressing between the actual symbol, and the filter impulse response function will be added on the sampled point and symbol sampler point of interpolation.Suppose the sampled point up-sampling to an interpolation of each symbol in the symbols streams, the impulse response function of filter will be added between interval on the symbol and the symbol position of half, on the up-sampling symbols streams on the just intersymbol interval.This is shown among Fig. 8, and the filter coefficient on interval on the symbol is represented with asterisk (*) therein, and filter coefficient is represented with crisscross (+) on intersymbol interval.Because the influence of symbol and intersymbol filter coefficient is when it will be added on the symbols streams when filter 126 occurs, in order to predict the response that reduces the unit median filter at peak value exactly, must both consider the filter coefficient on the interval on the symbol, also consider the filter coefficient on the intersymbol interval.Two stage process shown in Fig. 7 makes on this symbol and intersymbol processing can be implemented serially.This serial execution mode is compared with side by side, just carries out on the symbol concurrently and intersymbol is handled and can be used less hardware, or more uncomplicated DSP program.But, should be realized that, in a kind of alternative embodiment, can finish a kind of like this simultaneous mode, below describe a kind of like this embodiment.Each symbol has under the situation more than the up-sampling symbols streams of the symbol of 1 interpolation, for the filter prediction processing can increase regularly point of additional filter in for symbol sebolic addressing.Also should be realized that, though at least one symbol and intersymbol processing be preferred at present, it also is possible providing the peak value that has only (or intersymbol) on the symbol to reduce and handling and still obtain some useful result.In addition, because peak value reduces the peak value reduction error that the causal character of processing causes, any or all of level can be repeated in order to estimate.

Though the peak value that Fig. 6 showed before up-sampling circuit 124 reduces the unit, also can be configured in after the up-sampling circuit (before filter 126).When up-sampling is operated later on, directly obtain coefficient from the filter impulse response function by up-sampling speed.These coefficients are used to produce filter prediction of output device then.To on up-sampling speed, finish the filter prediction of output.To predict the outcome from these and finish the peak value reduction.This method is not preferred for some application and/or some impulse response function.When on up-sampling speed, working, can provide peak value to reduce to the null value symbol that during up-sampling, adds.Digital communication system as CDMA and WCDMA, is used transmission and receiving filter for making the intersymbol interference minimal design.In order to keep minimum intersymbol interference in communication period, the null value symbol that adds during up-sampling must remain null value.On up-sampling speed, work and also need on higher rate, handle.Generally, processing speed is high more, and the cost of processing unit is expensive more.Yet, having some application like this, these costs are inessential therein, do not need to be considered, and are preferentially adopted with reprocessing at up-sampling.Any modification that reduces specific embodiment necessity of unit for the later peak value of following described realization up-sampling will be significantly for those skilled in the art, be self-evident at this.

Two-stage among Fig. 7 can be used the reduction process shown in Fig. 9.With reference to figure 9, the reduction process comprises the source 144 of a filter coefficient.These filter coefficients are taken from the filter impulse response function on the symbol or on the intersymbol interval, and this depends on the processing level 140 or 142 among Fig. 7.These coefficient source can be taked the form of the memory 144 of memory filter coefficient, for example, for suitable mark space at the coefficient shown in Fig. 8.Certainly, other filter embodiment can have different filter response functions, and therefore different filter coefficients will be stored in the filter coefficient storage 144.These filter coefficients are provided for a filter fallout predictor 146, the influence that the incoming symbol that receiving road 148 along the line provides flows and simulate 126 pairs of symbols streams of filter on selected mark space, provide two outputs from the filter fallout predictor, an output 147 is to use the filter coefficient weighted sum of incoming symbol of the time diffusion of all input filter coefficients and equal number.Another output 145 is filter coefficient weighted sums of only using center-filter coefficient and the center mark that is complementary.When the filter coefficient of odd number was used, second output was to be used to calculate the center coefficient of first output 147 and the center mark of coupling.When the coefficient of even number is used, two center coefficient will have identical value, can be used by the center mark in company with two couplings and calculate first output 147.When entering the filter fallout predictor, every next new symbol produces two outputs by 146.Each new output is reduced algorithm process circuit 152 to offer peak value on the basis of symbol one by one.Peak value reduces algorithm process circuit 152 amplitude of first predictive filter output 147 and the peak value limit value L of predetermined maximum permission is made comparisons.If first predictive filter output 147 surpasses limit value, then peak value reduces the regulated quantity of algorithm circuit 152 calculating to second filter fallout predictor output 145, and this will cause being handled by the filter 126 of Fig. 6 will be still in the peak value limit value with postfilter output.This regulated quantity device 168 that is combined is applied on the corresponding symbol of being delayed time by delay circuit 166 on the basis of symbol one by one then.The adjusted symbols streams of peak value is exported along circuit 154 then.Various different algorithm can be used in peak value to be reduced in the algorithm circuit 152.Can be according to choosing specific algorithm for the desirable accuracy of specific application and accessible processing speed and/or desirable complexity of hardware.For example, a kind of approximate data may be acceptable fully in many application, provides desirable peak value and reduce in symbol sebolic addressing.

A kind of alternate embodiment of Fig. 9 is shown among Figure 10, the filter fallout predictor 146 of Fig. 9 therein, and delayer 166 and combiner 168 are merged into the parts of filter fallout predictor.The regulated quantity that is provided by peak value reduction algorithm 152 is sent back in the filter fallout predictor so that present regulated quantity is introduced in following prediction.When filter fallout predictor embodiment comes into question, this introducing will be discussed in more detail.

With reference to Figure 11, a kind of alternative embodiment that (Fig. 6's) peak value reduces unit 122 is illustrated.The embodiment of Figure 11 provides a kind of multistage peak value of multistage serial arrangement that utilizes to reduce the unit.

More specifically, with reference to Figure 11, shown peak value reduces the unit and comprises a plurality of independent levels 320.Reduce the filter coefficient that each grade 320 utilizes a cover and specific filter to export regularly corresponding periodic samples in the unit at peak value and apply the filter predicted operation.For example, if up-sampling inserts 9 zero between symbol, then the filter operations of the reality of Chan Shenging will comprise regularly point of 10 filters for each mark space.In order to provide filter operations complete precise analytic model, every bit was included in needs in the peak value reduction processing during these filters were regularly put.Like this, the filter impulse response function need be sampled on 10 different positions for each mark space.Be shown among Figure 12-21 for this example of a specific impulse response function in 10 filter sample positions of each mark space.Each illustrates different filter coefficient sampling timing in the mark space among these 10 figure.Particularly, Figure 12 is illustrated in-0.5 the timing at interval from the symbol, and just the paired pulses response function that departs from the mark space that begins of half point is periodically sampled between negative two symbols of time orientation (intersymbol).The impulse response function of sampling periodically on the mark space that Figure 13 represents to begin from-0.4 timing.Figure 14-21 represents the sampling timing of from-0.3 to+0.4 order that departs from successively.Therefore Figure 12-21 represents altogether for 10 symmetrical at interval on symbol filter coefficient sample position.Each grade 320 of peak value reduction unit carried out the filter predicted operation among Figure 11 on an independent sampling timing point.Therefore, for specific impulse response function and the sampling shown in Figure 12-21, the filter stage 320 of 10 separation will be provided, every grade with Figure 12-21 in one corresponding one regularly provide the filter predicted operation on the point.Specifically, level 320-1 can be corresponding to the sampling timing shown in Figure 12, and level 320-2 is corresponding in the sampling timing shown in Figure 13, etc.

Certainly, will recognize that 10 sampled points in Figure 11 and Figure 12-21 and 10 grades example are with explaining, more or fewer purpose sampled point and level can being provided purely.Level 320 number does not need corresponding with the specific quantity of the up-sampling that takes place yet, can adopt than the quantity of the up-sampling point of reality lack grade and the coefficient sampled point.Figure 11 also illustrates each peak value of arranging by the time order and reduces process from t=-0.5 to t=0.4.The time relationship of peak value reduction level can be to arrange by any random order in Figure 11.In addition, any or all level can be repeated to reduce error so that estimate by the peak value that the causality character that the peak value reduction is handled causes.

With reference to Figure 22, a kind of alternative embodiment that peak value reduces the unit is illustrated, and comprises that a kind of multistage peak value of implementing with parallel mode reduces processing.More than the peak value described about Figure 11 to reduce the unit embodiment be to reduce process by a kind of multistage peak value that serial mode is implemented.In the embodiment shown in Figure 22, a kind of similar multistage peak value reduction process is implemented with parallel mode.Just, implement peak value at every grade shown in Figure 22 360 according to the different timing of filter impulse response function median filter coefficient and reduce and handle, corresponding with the filtering of the higher rate that takes place behind the up-sampling to incoming symbol.For example, can adopt filter coefficient execution peak value to reduce processing at every grade shown in Figure 22 360 at the different timing up-sampling shown in Figure 12-21.Yet because under the situation of the embodiment of Figure 11, can adopt different timings and different specific filter impulse response functions, the specific filter coefficient of Figure 12-21 and coefficient sampling timing are with explaining purely.In addition, any or all symbol coefficients regularly can be repeated, and reduce error so that estimate by the peak value that the causality character that the peak value reduction is handled causes.

In the embodiment of former described Figure 11, each level in succession receives and imports as it from the adjusted symbol of the peak value of prime in multistage peak value reduction unit.Therefore, adopt this serial embodiment to avoid the peak value of the symbol of former adjusted mistake regulated and do unnecessary repetition.In the parallel embodiment of Figure 22, preferably adopt a kind of multi-level feedback method, peak value reduction value is reduced grade level that is transmitted back to other to reach similar result from parallel peak value.More specifically, the branch 0 of Figure 22, the peak value reduction process of the branch at top receives the feedback of the peak value reduction algorithm of controlling oneself inner from it, also this feedback is offered all lower branches.Lower branch as the i of branch, receives from its own inner peak value and reduces the feedback of algorithm and come the comfortable feedback of all branch roads on it.Last branch, the N-1 of branch receives the inside peak value that comprises from it and reduces the feedback of all branches of algorithm.As shown in Figure 22, the adjusted symbols streams of the level whole peak values of output of bottom.

With reference to Figure 23, a kind of replacement scheme to the parallel processing embodiment is shown.This embodiment is identical except the peak value that the feedback from all branches is provided for each branch reduces the unit with the scheme of Figure 22.The peak value that this alternative embodiment has been improved from each branch reduces calculating, because each calculating will be based on nearest adjusted symbol.

Because the peak value reduction is handled and finished with parallel mode in the embodiment of Figure 22 and 23, can finish soon than previously described serial embodiment.Therefore, in some cases, Figure 22 and 23 embodiment may be preferred.Because handle and also can be finished quickly, at more coefficient regularly and/or utilize more coefficient to implement the filter prediction, to reduce the accuracy of handling also be possible thereby utilize the parallel embodiment of Figure 22 to increase peak value.

With reference to Figure 24, the parallel peak value that Figure 22 and 23 are shown reduces the one-level 360 of unit.As shown in the figure, the incoming symbol for level 360 at first is provided for filter fallout predictor 372, the filter coefficient enforcement filter prediction processing of utilizing being illustrated in specific biasing-symbol timing to provide from filter coefficient source 144.Filter coefficient source 144 can be connected into circuit by rigid line, perhaps can take the form of suitable memory, as a register in a kind of properly programmed DSP embodiment that reduces the unit at peak value.As already pointed out like that, for the specific sample-offset of the filter coefficient that is supplied to filter fallout predictor 372 regularly regularly corresponding to the selected sample-offset on the up-sampling speed of the practical filter that in system, is adopted.Therefore, for example, the sampling timing as shown in Figure 12-21 can be applied to being stored in the filter coefficient that is used for each specific level 360 in the filter coefficient source 144.

The filtering of two kinds of predictions of describing in Fig. 9 of filter fallout predictor 372 outputs outputs to peak value and reduces algorithm circuit 152, implement a kind of suitable peak value therein and reduce algorithm to determine peak value reduction value, if necessary, peak value is reduced to desirable limit value.Calculate peak value reduction value be used as value of feedback F1 from level 360 output, be provided for it inside filter fallout predictor 372 and Figure 22 and 23 in the filter fallout predictor of other parallel branchs 360-1.

As noted above, various different algorithm can be at Fig. 9, and 10 and 24 peak value reduces in the algorithm circuit 152 to be implemented.A kind of such algorithm is shown among Figure 25.Figure 25 illustrates a kind of complex vector located figure, with explaining based on the filter coefficient weighted sum of the incoming symbol of utilizing all input coefficients and having only the filter output of the filter coefficient weighted sum of the incoming symbol that the center mark of center-filter coefficient and coupling is used.For being fit to that filter output is placed on filter in the limit value L that presets is that the symbol at center is from these two input calculated correction values.Designed in order to only range error is introduced incoming symbol by special at the algorithm shown in Figure 25.Some communication system more can be tolerated than phase error for range error.

More specifically, represented with vectorial A based on the filter output of center incoming symbol with reference to Figure 25.Based on many incoming symbols, comprise the center incoming symbol, predictive filter output represented with vectorial B.By getting the poor compute vector D of these two vectors.Therefore vectorial D represents a plurality of symbols that lack center mark vector A from filter output, and output gA represents a kind of adjusted form that gains of vectorial A, and when being added to D when going up, filter output is withdrawn into limit value level L.Be used to calculated gains g at remaining vector shown in Figure 25.By following a series of vector calculation calculated gains g.

L ²＝z ²+y ²

$z=\sqrt{L^2-{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="C0180828300401.png,C0180828300431.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}$

$g\left|A\right|=\sqrt{L^2-y^2}-x$

$x=\frac{D\&CenterDot;A}{\left|A\right|}$

$y=|D-\frac{(D\&CenterDot;A)A}{{\left|A\right|}^2}|$

$g=(\sqrt{L^2-{|D-|\frac{(D\&CenterDot;A)A}{{\left|A\right|}^2}|}^2}-\frac{(D\&CenterDot;A)}{\left|A\right|})\frac{1}{\left|A\right|}---\left(1\right)$

This algorithm can be by using a kind of DSP that is suitably programmed or other processor at Fig. 9, and the peak value shown in 10 and 24 reduces in the algorithm circuit to be implemented.Because this algorithm comprises the square root of getting some vector quantities, how much this may be high-intensity calculating, therefore may wish to adopt a kind of approximate data, in most of the cases also will provide suitable symbol correction.Particularly, if supposition, the difference of exporting between the A at the output B and the single symbol of prediction is quite little, and just D is very little in above equation.Can use following approximate formula to calculate filter output is reduced to the required gain g of limit value L.

$g\&ap;\frac{L+\left|A\right|-\left|B\right|}{\left|A\right|},$ For little ' D ' (2)

Utilize then above accurately or approximate algorithm calculate yield value be applied to the combiner 168 shown in Fig. 9.Combiner can be exactly a multiplier circuit, and gain g is multiplied each other with the incoming symbol that produces output vector A.Another kind of scheme is that if the vectorial regulated quantity that is provided by following equation (3) is provided the gain calculating that obtains in above (1) and (2), combiner can be changed into an add circuit.Value gc is applied among Figure 25 gain on the center mark that produces vectorial A by filter.

$V=(A-\mathrm{gA})\frac{1}{g_c}---\left(3\right)$

As already pointed out, various different algorithm can be used to calculate predictive filter is exported the symbol regulated quantity that is placed in the limit value L.A kind of so additional algorithm is shown among Figure 26, and the calculating by a updating vector of addition and the combination of center incoming symbol is shown.This algorithm is different with the algorithm of Figure 25, and regulated quantity allows phase error therein, so that make the resultant distortion energy that adds for minimum.More specifically, as shown in Figure 26, has identical meaning among the vectorial A, B and D and Figure 25.At Figure 26 intermediate value C is in order to make predictive filter output be placed on the additional adjusting that output is done to predictive filter on the limit value L.Though various adjusting vector can be placed on the limit value L vector of gained by affix, is that minimum is desirable thereby make the size correcting value of vectorial C, because any change that incoming symbol is made all might cause some distortion in the signal.Basic vector algebra is applied to the vector shown in Figure 26 obtains following equation, be defined as obtaining desirable peak value in limit value L and reduced output, be applied to the correcting value C of center mark filter output A:

$C=(L\frac{B}{\left|B\right|}-B)---\left(4\right)$

With the addition of symbol regulated quantity before, above vector must be to be applied to the gain that the inverse filter gain of the center mark that is used for compute vector C is regulated.Providing in (5) in order to regulate symbol makes peak value reduce resulting algorithm.This algorithm can be implemented in the circuit of properly programmed DSP or other hardware or software realization.

$V=(L\frac{B}{\left|B\right|}-B)\frac{1}{g_c}---\left(5\right)$

In above equation (5), calculate then the updating vector value be applied on the combiner 168 shown in Fig. 9.Combiner can be exactly an add circuit, and vectorial V is added on the center mark that produces output vector A.Another kind of scheme is that if the gain adjustment amount that is provided by following equation (6) is provided the vector calculation that obtains in (4), combiner can be changed into a multiplier circuit.

$g=(A+C)\frac{1}{A}---\left(6\right)$

Those skilled in the art should be realized that, in fact purely be with explaining at two kinds of algorithms shown in Figure 25 and 26 respectively, various different algorithm can suitably be adopted and can or be comprised Fig. 9 at DSP, implements in other circuit of the peak value reduction algorithm circuit 152 shown in 10 and 24.

With reference to Figure 27 and 28, reduce the example of handling according to peak value of the present invention and be shown among two complex vector located figure.Figure 27 and 28 is applicable to the occasion of having only a center mark to be conditioned.Yet shown center mark can be represented the combination of two center marks.As shown in Figure 27 and 28, incoming symbol is provided the filter fallout predictor and handles.Because filter output is relevant with many symbols in time, is not only the center mark that is conditioned, output can be represented as the circle of the influence of adjacent symbol on center mark and the express time.

Though originally center mark surpasses limit value in two examples, in the example of Figure 27, represent that in fact the part of the circle of the output of filtering is positioned at the limit value line.Therefore these output valves and reduce without undergoing peak value and to handle.Surpass the degree of limit value line by the symbol of filtering and the amount that changes stands peak value and reduces and handle at the remainder of the output shown in the thick line part of the plural figure of Figure 27 and 28.Symbol is conditioned the filter output that makes prediction and is pulled back to the limit value line then, shown in limit value line thick line part in Figure 27 and 28.Therefore, to recognize, the symbol that does not need peak value limit to handle still was not touched, thereby reduced any distortion of introducing by such reduction, and needed peak value to reduce the MIN peak value reduction amount that the symbol of handling is provided as filtering output is placed necessity in the limit value.Otherwise, it seems that originally not needing peak value to reduce the symbol of handling will be regulated by peak value, if the filter prediction shows that this filter will be above limit value.Therefore, will recognize that the invention provides highly effectively, signal peak reduces and makes the distortion of created symbol sequence be minimum simultaneously.

Figure 29 to 35 illustrates and utilizes equation (1), and (2), the different peak value of the algorithm that provides in (3), (5) and (6) reduces the unit embodiment.Figure 29, the peak value shown in 30,32 and 34 presentation graphs 9 reduces processing.Figure 31, the reduction shown in 33 and 35 expression Figure 10 is handled.An example in the parallel processing shown in Figure 23 and 24 will provide in Figure 36 A and 36B.

With reference to Figure 29, utilize a kind of peak value reduction unit embodiment of equation (1) to be illustrated with the block schematic form.As shown in Figure 29, adopt a kind of multitap filter 200 easily the filter predictor circuit shown in delay circuit 166 and Fig. 9 146 to be made up.Filter 200 comprises a plurality of independent memory registers 202, wherein in the specific embodiment that 5 are shown in Figure 29.Yet should be realized that, additional or less delay memory register can be provided, General N such memory register 202 will be provided the shift register of forming N element, by a memory register is exported tap, for example, at central memory register place, can provide the symbol sebolic addressing of a time-delay, making peak value proofread and correct can finish on by the basis of correct symbol one by one regularly on combiner 168.A kind of like this time-delay output from N element memory register illustrates with line 205, and it is corresponding to the output of the delay circuit shown in Fig. 9 166.The output that is provided along line 204 is to obtain from a tap with the later center delay line of center-filter multiplication.This line is represented the symbol of the filtering output (line 145 among Fig. 9 and the vectorial A among Figure 25) at center, and the peak value that is provided for as shown in Figure 29 reduces algorithm process circuit 152.Be provided for corresponding multiplier 206 from the time-delay output of each in the memory register 202, this multiplier also receives the input of corresponding filter coefficient as it.Therefore each filter coefficient plays a gain g _NEffect, N=1 to 5 is with the symbol output multiplication from corresponding delay stages 202.Filter coefficient g _NCan corresponding in the mark space coefficient shown in Fig. 8 or Figure 12-21 any one, depend on which rank of is illustrated in the processing of Fig. 9 or 11.Certainly, can use various different filter response function, this depends on predicted specific filter, and its coefficient will correspondingly change.Also will recognize, utilizing is the example of illustrative five coefficients in fact purely, can obtain additional coefficient from any mark space of impulse response function, can adopt greater or less than five coefficients for specific embodiment, this depends on by the speed and the desirable accuracy of the treatment system of modeled specific impulse response function and employing.

Again with reference to Figure 29, be provided for add circuit 208 from the output of multiplier circuit 206, a plurality of output phase adductions are provided them along line 210.Along the output of line 210 filter coefficient weighted sum corresponding to the symbol of on specific mark space, obtaining, thereby corresponding to during this time every the model of last filter to the influence of symbol.The filter symbol output of this prediction is provided along line 210, as an input that peak value is reduced algorithm circuit 152.Such as noted above, peak value reduces algorithm circuit 152 also receives time-delay along line 204 center mark filter output.The center mark filter output stream of this time-delay is offered subtraction circuit 216 and is offered APU 218 along line 214 along line 212.Like this, the filtering that subtraction circuit 216 receptions provide along line 210 is exported as an input to it, and reception is exported second input of conduct to it along the center mark filter of the time-delay of line 212.Subtraction circuit 216 is got the poor of these two output streams, and providing one by one, the difference D of symbol (utilizes the term of Figure 25, D=B-A), gives APU 218 along line 220.APU 218 receives two incoming symbol streams along line 220 and 214, also receives limit value L as input.APU 218 is utilized equation (1) calculated gains g, so that filtering output is reduced to the value that is positioned at limit value L.

In a more general case, subtraction circuit 216 will make up with APU 218, set up a kind of more general APU.By this minor modifications to Figure 29, input and limit value L based on from line 204,210 can use various different algorithm.Under this more general situation, can use the approximate data that in equation (2), provides or in equation (6), provide, based on the algorithm of Figure 26.

Under the particular case shown in Figure 29, or under the described more general situation, from APU 218 calculate yield value g outputed to selector switch 230 along line 232.

With reference to Figure 29, the output stream of filtering that provides along line 210 also is provided for value testing circuit 222 again.Be worth most testing circuit 222 and determine the value of the output of filtering, just, comprise the absolute value of the complex vector located amount of this output, this value is provided as output along line 224.This value is provided for comparator 226, with the value and the limit value L of filtering symbol make comparisons.If the value of filtering symbol surpasses limit value L, get first value (for example " 1 ") from the output of comparator 226.If the value of filtering symbol is less than limit value L, then the output from comparator 226 is one second value (for example, " 0 ").Then, this value, just " 0 " or " 1 " is used as output and offers selector switch 230 along line 228.If 230 input is 0 along line 228 to selector switch, then the output from selector switch 230 is a unit signal, its not influence of symbols streams to offer combiner 168 (illustrating as a multiplier) in the specific embodiment of Figure 29 along line 205.If offering the signal of selector switch 230 along line 228 is 1, surpass the situation of limit value L corresponding to filtering value of symbol, then from calculating of providing of APU 218 yield value g be output to multiplier 168.Only be necessary on the basis of symbol one by one in this way, the symbols streams that provides along line 205 will be calculated by algorithm the gain that reduces of appropriate value, the symbol that suitable peak value is conditioned will be exported on online 154.

To recognize, can only use hardware, only use software, realize as a properly programmed DSP or other processor that just a kind of combination that perhaps can be used as hardware and software realizes at the various circuit blocks shown in Figure 29.For example, filter 200 is used as hardware and realizes, and APU 218 is used as the dsp processor of suitable coding and realizes it may being favourable.Another kind of scheme is that the circuit of APU 218 can be used as a programmable gate-array circuit and realize.Filter 200 and/or difference circuit 216 and value detector 222 also can be used as a gate-array circuit and realize, and with circuit 218 combination based on processor.Therefore, will recognize, be possible in the combination of the various different embodiment of the circuit shown in Figure 29.

With reference to Figure 30, a kind of embodiment that substitutes that reduces the unit at the peak value shown in Figure 29 is shown.In the embodiment of Figure 30, in a kind of peak value reduction algorithm circuit 152 of simplification, implement peak value and reduce algorithm, utilize an approximated equation that reduces for peak value so that be applied on the incoming symbol.Particularly, can implement equation described above (2), provide for being applied to symbolic vector so that take it a kind of approximate calculation of the gain g of limit value L in the specific embodiment shown in Figure 30.

Just as can be seen, this equation comprises quite simply calculating.Relate to limit value L, the value of the filtering output B of the value of center mark filter output A and prediction.Peak value shown in this equation and Figure 30 is reduced algorithm circuit 152 make comparisons and show circuit 222,250,252,254 and 256 realize equation (2) in flat-footed mode.More specifically, line 204 provides center mark filter output A together with value testing circuit 250, and the filtering output of prediction is provided from filter 200 to value testing circuit 222, determines the value of the filtering output B of prediction.These two values are provided for subtraction circuit 252, as the row signed magnitude subtraction with the value of providing | A|-|B|.Adding device circuit 254 (ifs circuit 252 its inputs of exchange, it can be a kind of subtraction circuit) then will be added on the limit value L from this value that circuit 252 provides.Be provided for division circuit 256 from the center filtering output that circuit 250 provides, it is the output of receiving circuit 254 also, reduces gain g so that the approximate peak that is provided by above equation (2) to be provided.

Therefore, will recognize that a kind of embodiment that quite simply can provide with hardware easily is provided the circuit embodiment that is used for peak value reduction algorithm circuit 152 shown in Figure 30.This hardware can adopt the form of programmable gate array or other hardware embodiment, perhaps is used in the quite simple program of implementing in DSP or other processors and realizes.Can have the advantage of cost and/or speed in this suitable characteristic of simple of the embodiment shown in Figure 30, in specific application, can preferentially be selected for use.What the remainder of circuit can be with shown in Figure 29 in the embodiment shown in Figure 30 is accurately identical, and identical exactly mode available with described above is operated.Therefore, in order to describe the embodiment of Figure 30, the operation of this omnibus circuit will do not repeated.

With reference to Figure 31, the embodiment that substitutes that a kind of peak value reduces the unit is shown.The embodiment of Figure 31 adopts the feedback that outputs to the filter fallout predictor that reduces algorithm circuit 152 from peak value, so that increase the accuracy of filter predicted operation.Therefore Figure 31 represents a kind of embodiment of Figure 10.More specifically, as in the former embodiment of having described, filter fallout predictor and delay circuit preferentially are combined in the finite element filter 200, a plurality of memory registers that receive incoming symbol are merged, as the shift register operation of a N unit.As in the situation of the embodiment of Figure 29, the output of memory register is provided for multiplier circuit 206, it also the receiving filter coefficient as its input.Also as in the situation of the embodiment of Figure 29, multiplier output is provided for adder circuit 208, so that the output symbol of filtering to be provided.Yet, peak value shown in Figure 31 reduce algorithm circuit 152 also with Figure 29 in corresponding, as about before embodiment more than discussed, it can be modified to implement various different algorithm.

Contrast with the embodiment of Figure 29, the output of peak value reduction algorithm circuit 152 is sent back to filter 200 in Figure 31.Particularly, the output that peak value reduces algorithm circuit 152 is transmitted back to multiplier along line 162, provide by circuit 152 calculate peak value reduce the output of in the N level memory register of the filter 200 center delay stages of gaining.As a result, the output that offers the multiplier 168 of memory register downstream stage comprises the value of symbol that gains and reduce.This will reflect the actual treatment (with reference to figure 6) that filter 126 carries out more accurately, because the symbol that gain reduces is included in filtered device 200 in the calculating of filtering symbol.Therefore, provide more accurate filter prediction in many cases, in many application, can preferentially be selected for use in the embodiment shown in Figure 31.

Can carry out a kind of similar feedback to the embodiment shown in Figure 30 and extend, wherein equation (2) quilt limits with the block diagram of a uniqueness specially.This extension should be understood by those skilled in the art easily.

As mentioned above, feedback is revised for all peak value adjusting calculating subsequently adjusted symbol is provided.Yet before modification, the symbol of Tiao Jieing is used to calculate the peak value regulated quantity before the adjusting time in advance.This means that when adjusted symbols streams is passed through filter (20 among Fig. 6) adjusted symbol will participate in setting up the peak value of adjusted symbol front and back.Like this, new peak value can be set up before adjusted symbol.These new peak values are the causality of peak value adjustment process or the result of non-desirable properties.Repeat Fig. 7 simply, the peak value shown in 11,22 and 23 reduces process can easily eliminate these new peak values.

Embodiment has in the past been described based on the symbol of gain calibration and has been regulated, and these gain calibrations can be from equation (1), and calculate (2) and (6).Symbol is regulated also can be based on the additional vector that can calculate from equation (3) and (5).With reference to Figure 32, a kind of embodiment of regulating symbol based on additional vector is shown.In the embodiment of Figure 32, the delay circuit of Fig. 9 is used as the parts of a series of memory registers and realizes, to form the parts of filter predictor circuit 146 with the similar mode of the embodiment of describing in the past.More specifically, filter 200 comprises a plurality of memory registers 202, can be used as the shift register work of N unit, and special explanation figure is 7 yuan of shift registers.The output of memory register centre grade is done an output by tap, and the symbol that time-delay is provided along line 205 is to combiner 168.Combiner 168 illustrates as an adder circuit.The output of memory register level is provided for multiplier circuit 206, and it is also received in the input of the filter coefficient value of corresponding with this grade specific symbol on regularly as it.The output of multiplier 206 is provided for add circuit, and is along the filter output value of line 210 predictions of output, similar with the embodiment of describing in the past.

The filter output of prediction offers peak value along line 210 and reduces algorithm circuit 218, and in predictive filter output, implement specific peak value and reduce algorithm, and the reduction value is provided, if any, to combiner 168.In the embodiment of Figure 32, can implement a kind of special simple algorithm, it need be along the input of line 204 from center filtering symbol output, and operation in the filter output of the prediction that provides along line 210 simply.For shown in this algorithm of specific embodiment also adopt the centre tapped gain g4 of desirable limit value L and filter fallout predictor as input.A kind of like this algorithm can be corresponding to above about the described equation of Figure 26 (5).Yet other algorithm also can be used in the circuit 338.The input from symbols streams that these other algorithm may provide along line 204 obtains understanding under the situation of these embodiments that substitute for the possibility of a kind of like this input of circuit among Figure 32 152.Just provide a kind of like this algorithm in equation (3), wherein the value g in the equation (3) calculates in equation (1).

Shown in the embodiment of circuit 152 in, the value of the filter output of the prediction that provides along line 210 is determined by value testing circuit 222.This value is provided for a comparator 226, and the value and the threshold value L of filter output value of prediction made comparisons.The filter output of prediction also is provided for APU circuit 218, can be a properly programmed DSP or other processor, the equation of the particular shown in implementing to be used for or to other suitable algorithms of the symbol manipulation of prediction.Another kind of scheme is that APU 218 can realize with gate array architecture or other hardware embodiment.Be provided for selector switch 230 from the output of APU 218, this switch also receives the output of comparator 226.If the value of symbol of prediction is greater than threshold value L, then the output from comparator makes switch 230 can export peak correction values to combiner 168.Otherwise if the value of symbol of prediction is less than or equal to limit value L, then comparator selects zero output to combiner 168 to the output of selector switch 230, does not regulate corresponding to symbols streams there being peak value.

With reference to Figure 33, a kind of alternative embodiment of Figure 32 is shown, as given among Figure 10, adopt the feedback of peak value adjusting to the filter fallout predictor.More specifically, in the embodiment of Figure 33, filter 200 reduces the peak value regulated value that algorithm circuit 218 receives feedback along line 262 from peak value.Therefore filter 200 shown in Figure 33 as in the situation of Figure 32, can not need to describe in detail corresponding to the embodiment of a N level.As shown in the figure, the peak value regulated quantity that provides along line 262 can be provided for combiner 168, illustrates as an adder in Figure 33, is configured in after the centre grade of memory register, forms the parts of filter 200.Therefore, the peak value of symbol is regulated in the level in succession that is included in filter, provided additional improvement the predictive ability of filter 200.To recognize, and utilize feedback positions different in the memory register can realize different filter embodiments easily.Therefore, be in fact to be used as restriction purely in the specific embodiment shown in Figure 33 with explaining, should not be in.

With reference to Figure 34, the peak value that a kind of Figure 29 is shown reduces the embodiment block schematic that substitutes of circuit unit.In order to understand the reasonability of this alternative embodiment, remember by the dominant intersymbol peak value of the symbol of two adjacent similar amplitudes.This described in reference to figure 4 above.If only finish on the symbol and intersymbol adjusting, the symbol of a large amount of similar amplitudes will be arranged after handling on symbol.Two adjacent-symbols placed in the middle were conditioned in longer-unit of time-delay and filter fallout predictor memory register, Figure 34 was corresponding with Figure 29 basically.Two center coefficient have identical value.

Corresponding with Figure 29 basically in the embodiment of circuit shown in Figure 34, therefore same numeral is applied to same parts, thereby the detailed description of each parts will no longer repeat.As above discuss about Figure 29, this circuit utilizes tap filter 200 more than, carries out the influence of predictive filter impulse response to incoming symbol on intersymbol interval, and provides peak value reduce to handle based on this.Filter 200 is except following some modifications, and is in general corresponding with the filter 200 among Figure 29.Input g to multiplier 206 _N, N=1 to 6 is selected from intersymbol filter coefficient (t=0.5) at interval, as representing with cross symbol in Fig. 8 at the specific impulse response function shown in this.Such as discussed with respect to FIG. 29, specific filter coefficient is with explaining, so input g in fact purely in Fig. 8 _NBe not limited to specific intersymbol value shown here.In order to provide symbol correction, be provided for an add circuit 240 so that set up line 204 from the filter output of two center-filter tap 202-3 and 202-4 to main two symbols that influence the intersymbol peak value.Line 204 is equivalent at the single sign filter output A shown in Figure 25 and 26.By using the memory register 244 and the multiplier 242 of individual unit, utilization is applied to two centre tapped gain calibrations and handles the peak value adjusting as before then.Therefore, will recognize that the output symbol stream on online 154 is provided on the intersymbol interval, the symbol symbols streams that suitable peak value is adjusted of regulating one by one, rather than with identical about method that Figure 29 discussed.Though handle be preferably among Figure 34 with Figure 29 in identical, in some cases, may wish to implement in Figure 34 algorithm different with Figure 29 or another kind of method is to handle being revised as on intersymbol interval in processing on the interval on the symbol.

With reference to Figure 35, the embodiment that substitutes of a kind of Figure 34 is shown, also by using feedback about the described mode of Figure 31.More specifically, as shown in Figure 35, filter 200 comprises the feedback that reduces algorithm circuit 152 from peak value.This feedback loop provide by peak value reduce algorithm circuit 152 calculate be used for the gain g that peak value reduces, along the N level memory register of line 262 to the parts of forming filter 200.Shown in specific embodiment in, the gain of this feedback is provided for multiplier 168-1 and the multiplier 168-2 on the opposite side of the 4th memory register.Like this two symbols that influence the intersymbol peak value are most introduced in the symbol gain.This embodiment is based on the specific intersymbol impulse response function of Fig. 8 and the specific selection of filter delay stages.Therefore, utilize different filter embodiments or can provide different modes to introduce feedback oscillator recognizing to the memory register level for different impulse response functions.From the last level of memory register, provide the output of the reduction process of level along line 154 as shown in the figure.As in the situation of the embodiment of Figure 31, the feedback that symbol reduces is introduced memory register and can be improved the predictive ability of filter 200 and can preferentially be selected for use in some cases.

Figure 34 and 35 describes the embodiment that substitutes to Figure 29 and 31.Can finish the embodiment that similarly substitutes to Figure 30 and 32.These embodiments that substitute should be understood for those skilled in the art from above explanation.

With reference to figure 36A and 36B, the parallel multistage peak value that Figure 23 is shown reduces a kind of detailed embodiment of unit.Comprise that in the specific embodiment shown in Figure 36 A 10 parallel peak values reduce the processing level.Yet, will recognize that this is with explaining, depending on that specific applicable cases can adopt more or fewer purpose level purely.As former mentioning, the level that the peak value that the causality character that is reduced by peak value causes can be repeated is removed.In parallel processing, by to the periodic samples of the impulse response function in Figure 12 to 21, carried out realize this repetition continuously, the sampling of indication cycle's property obtains on-0.5 to 0.4 in these figure.The sample of obtaining on t=0.5 will be identical with the sample of obtaining on t=-0.4.Duplicating of this sampling figure will be carried out on the t=-0.5 to 0.5 of interval continuously.The sampling of these repetitions can be added to the bottom of Figure 36 A as parallel line 10,11 etc. then.

Every grade comprises a delay circuit 370, as shown in the figure, can be used as a series of memory registers and implements, and wherein each is with the time time corresponding between symbols streams time-delay and the symbol.As before, these memory registers are taken from tap, so that calculate the filter coefficient weighted sum that is stored in the symbol in the memory register.As shown in Figure 36 A, the memory register of an additional time-delay must be added to parallel level in succession.These delay registers are used for the correct timing of regulating from the feedback symbol of parallel level.

These are from each parallel delay stages T _{I, n}, i=0 to 10, the independent tap of n=0 to 7 is provided for a filter fallout predictor 200, and fallout predictor provides and outputs to multiplier 206 (with reference to figure 36B, the filter fallout predictor for the i level being shown), and multiplier receives each filter coefficient g _{I, n}As its second input.The output of multiplier 206 is provided for add circuit 208, and adder provides the filter coefficient weighted sum of the symbol that is stored in the memory register.Therefore the output along line 210 is illustrated in and present filter coefficient g _{I, n}The prediction of filter output in the relevant timing (Fig. 6 126).

The output of the filter fallout predictor 200 that provides along line 210 is provided for peak value and reduces algorithm computation circuit 218.Shown in specific embodiment in, peak value reduces algorithm computation device circuit and comprises a value testing circuit 222, this testing circuit receives the filter of having predicted the output along line 210, and detects its amplitude.The value that the filtering output of having predicted is detected is provided for comparator 226, and comparator also receives predetermined limit value L and center-filter tap gain g4.Under the situation as in front embodiment, if the filter value of symbol of prediction surpasses limit value, then a switch enable signal is provided for selector switch 230.Otherwise if the filter value of symbol of prediction is less than or equal to limit value, switch 230 is enabled, so that the adjusting peak value is not provided, for example, the null value in selected embodiment.The filter output of prediction also is provided for APU 216, can implement many suitable peak values and reduce in the algorithm any one.Shown in specific embodiment in.Receive only the filter value of symbol of prediction, limit value L and the centre tapped gain that is applied to filter fallout predictor g4 are as input, and the suitable algorithm of being implemented by circuit can be equation (5).Then, the output of APU 218 is used as a feedback peak value reduction value Fi and gives other levels, if for such output, selector switch 230 is compared the words that device 226 enables.

Each parallel branch produces the symbol regulated quantity of feedback, and these feedback regulation amounts are provided in the parallel branch each, makes nearest value of symbol can be included in following filter predicted value.Feedback to branch can be implemented in two ways.This dual mode is shown in Figure 22 and 23.Figure 36 is illustrated in the implementation of the embodiment shown in Figure 23.The symbol of each parallel branch is regulated and is provided for all parallel branchs.Shown in the not superincumbent branch of the feedback of following branch, because feedback will occur in after the memory register of last tap.If the feedback of the branch that each is independent be sent back to it self with all below branch, Figure 36 can be modified and represent Figure 22.The embodiment of Figure 22 is poorer slightly than the accuracy of Figure 23, because the prediction in the future of all branches will be based on the most current value of symbol.Yet Figure 23 will provide effective peak value to reduce.

Those skilled in the art should be realized that Figure 36 A and 36B illustrate a kind of parallel embodiment of Figure 33, comprises the additional feedback from other parallel levels.Those skilled in the art should be realized that also all embodiments that comprise the feedback that resembles Figure 31 and 35 can revise in the same way so that use in above parallel embodiment.

It should also be realized by those skilled in the art that by in a long multi-stage shift register, providing multistage tap also can be created in Figure 22 each memory register, 23 and 36A shown in parallel embodiment.By the filter coefficient of feedback tap for correspondence suitably divided into groups, calculate feedback correction value with parallel mode with the method shown in Figure 24 and the 36B.The value of feedback that obtains of parallel computation will be sent back to the feedback point shown in Figure 36 A line 9 then.

Many different embodiments of the present invention are described with reference to various figures.Yet, person of skill in the art will appreciate that various additional embodiment all is possible in the scope of instruction of the present invention.For example, adopt instruction content of the present invention that the various specific circuit of implementing special algorithm can be provided, the restriction in space can not be listed the inventory of all possible circuit embodiment or enumerate all possible algorithm.Various other possible modifications and additional embodiment obviously also are possible, and fall within the scope of the invention.Therefore, described specific embodiment and process should not be counted as actual restriction going up in all senses, and just with explaining the present invention.

Though the conduct of shown peak value reduction system and method for the present invention is at spread spectrum communication system, be illustrated as the practice in CDMA and the WCDMA Cellular Networks, these systems provide a kind of preferred application of the present invention, should be realized that the system and method for other application and environment reduce to(for) peak value of the present invention also are possible.For example, peak value of the present invention reduces system and method and also can be applied in easily in the multicarrier cellular basestation of spread spectrum communication system not necessarily.Therefore, reduce the described specific application of system and method and environment for peak value of the present invention and should not be counted as actual restriction going up in all senses, and just with explaining the present invention.

Claims (79)

1. spread spectrum communication system comprises:

The spread symbol generator is used to receive the data channel of a plurality of separation and they is combined, so that the spread spectrum data symbol to be provided;

Filter is used for providing filtering operation according to the filter impulse response function; With

Peak value reduces the unit, and be coupling between described spread symbol generator and the described filter, and receive described data symbol from described spread symbol generator,

This peak value reduces the unit and comprises:

Filter fallout predictor, this filter fallout predictor use the filtering output that prediction is provided with the corresponding filter coefficient value of filter impulse response function of described filter;

Peak value reduces counting circuit, is used to receive the filtering output and the predetermined filtering output limit value of prediction, and exports the quantity that surpasses limit value according to the filtering of prediction and determine peak value reduction value; With

Combiner is used for peak value reduction value and data symbol combination,

This peak value reduces unit provides the adjusted symbol of peak value to this filter, so that filtering and export these symbols by this communication system.

2. spread spectrum communication system as claimed in claim 1 also comprises the up-sampling circuit, is coupling in peak value and reduces between unit and the filter, the data symbol that is used for increasing the sample rate of data symbol before filtering and up-sampling is provided.

3. spread spectrum communication system as claimed in claim 2, wherein the above sampling filter speed of this filter provides described filtering operation to the data symbol of up-sampling.

4. spread spectrum communication system as claimed in claim 1, wherein this peak value reduces unit and also comprises a delay circuit, is used for the delay data symbol, so that combiner mode with time synchronized on the basis of symbol one by one receives peak value reduction value and data symbol.

5. spread spectrum communication system as claimed in claim 2, wherein this filter fallout predictor receive with the corresponding first group of filter coefficient of the sample of the filter impulse response function on the interval on the symbol and with second group of corresponding filter coefficient of sample of filter impulse response function on intersymbol interval.

6. spread spectrum communication system as claimed in claim 5, wherein this peak value reduction unit comprises based on the first order that regularly provides peak value to reduce on the symbol and the second level that regularly provides peak value to reduce based on intersymbol.

7. spread spectrum communication system as claimed in claim 1, wherein this combiner comprises a multiplier circuit, wherein this peak value reduction value comprises a gain, and this gain provides adjusted symbol when it and data symbol multiply each other, and this will produce the output signal that peak value reduces.

8. spread spectrum communication system as claimed in claim 1, wherein this combiner comprise an add circuit and wherein this peak value reduction value comprise a value, this worthwhile it adjusted symbol is provided when being added on the symbol, this will produce the output signal that peak value reduces.

9. spread spectrum communication system as claimed in claim 4, wherein this filter fallout predictor comprises that the memory register and wherein one or more delay stages that contain a plurality of delay stages comprise described delay circuit.

10. spread spectrum communication system as claimed in claim 1, wherein this filter fallout predictor comprises the memory register that contains a plurality of delay stages, wherein each described delay stages is corresponding to an independently filter coefficient input.

11. spread spectrum communication system as claimed in claim 10, wherein this filter fallout predictor comprises a plurality of multipliers, the quantity of these multipliers equate with a plurality of delay stages that contain described memory register and wherein each described multiplier receive one of described filter coefficient.

12. spread spectrum communication system as claimed in claim 11, wherein this filter fallout predictor also comprises an add circuit, receives the output of described a plurality of multipliers.

13. spread spectrum communication system as claimed in claim 12 wherein has the described memory register of N level, a N multiplier and N filter coefficient input, wherein N is less than or equal to the number of the filter coefficient of described filter.

14. spread spectrum communication system as claimed in claim 1, wherein said peak value reduce counting circuit and comprise:

The value testing circuit is used to detect the value of the predictive filtering output of input; With

Comparator, the limit value of value that the predictive filtering that is used for importing is exported and signal output peak value compares.

15. spread spectrum communication system as claimed in claim 14, wherein this peak value reduction unit also comprises a selector switch, is coupled to comparator, and makes peak value reduction value can be output to combiner when described switch is compared when device starts.

16. spread spectrum communication system as claimed in claim 14, wherein this peak value reduction counting circuit also comprises an APU, is used for implementing a kind of peak value according to the filtering output of limit value and prediction and reduces algorithm.

17. spread spectrum communication system as claimed in claim 16, wherein this peak value reduction counting circuit also comprises a subtraction circuit.

18. spread spectrum communication system as claimed in claim 16, wherein this peak value reduction counting circuit also comprises a division circuit.

19. spread spectrum communication system as claimed in claim 1, wherein this peak value reduction unit also comprises a feedback loop, and this feedback loop offers the filter fallout predictor with peak value reduction value.

20. spread spectrum communication system as claimed in claim 19, wherein this filter predictor comprises the memory register that contains a plurality of delay stages, and wherein this feedback loop provides described peak value reduction to be worth to the described memory register between these delay stages.

21. spread spectrum communication system as claimed in claim 1 also comprises digital-to-analog converter, is coupled with the output of receiving filter and the RF amplifier output of this digital-to-analog converter.

22. spread spectrum communication system as claimed in claim 21 also comprises the transmitting antenna that is coupled to the output of RF amplifier.

23. spread spectrum communication system as claimed in claim 1, wherein this spread symbol generator comprises: a plurality of input channels that are used to receive the digital data channel of a plurality of separation; A plurality of spreading code circuit, the quantity of the digital data channel that the quantity of these spreading code circuit equals to separate, each spreading code circuit provides different spreading codes; With a plurality of multiplier circuits, be used for one of spreading code is multiplied each other with one of digital data channel that separates, and a plurality of spreading channels are provided.

24. spread spectrum communication system as claimed in claim 23 also comprises the spreading channel combinational circuit, is used for each spreading channel is combined, to form the data symbol of combination.

25. a spread spectrum communication system comprises:

The spread symbol generator is used to receive the data channel of a plurality of separation and they is combined, so that the spread spectrum data symbol to be provided;

The up-sampling circuit is used to increase the sampling rate of the symbol that inputs to it and the up-sampling symbol is provided;

Filter is used for providing filtering operation according to the filter impulse response function, has and corresponding a plurality of filter coefficients of timing based on the sample rate of described increase; With

Peak value reduces the unit, be coupling between described spread symbol generator and the described filter, and receive described data symbol from described spread symbol generator, this peak value reduces the unit and comprises that a plurality of peak values reduce level, every grade of use is predicted the influence of this filter to the data symbol with a part of corresponding filter coefficient value of the filter impulse response function of described filter, so that the filtering output of prediction to be provided, and provide peak value to reduce to the predictive filtering output that surpasses the peak value limit value to handle, this peak value reduces the unit provides the adjusted symbol of peak value to described filter after described multistage peak value reduces processing, wherein said filter carries out filtering to the adjusted symbol of these peak values, exports these symbols by this communication system subsequently.

26. spread spectrum communication system as claimed in claim 25 wherein provides described multistage described peak value to reduce the unit with serial mode.

27. spread spectrum communication system as claimed in claim 25 wherein provides described multistage described peak value to reduce the unit with parallel mode.

28. spread spectrum communication system as claimed in claim 25, wherein every grade peak value reduction unit adopts the up-sampling corresponding filter coefficient of timing slip regularly that departs from integer number with character rate.

29. spread spectrum communication system as claimed in claim 25, wherein every grade peak value reduction unit comprises:

The filter fallout predictor is used to receive the filter coefficient corresponding with the described part of filter impulse response function, and the filtering output of described prediction is provided; With

Peak value reduces counting circuit, is used for exporting according to the filtering of the prediction that is provided by this filter fallout predictor calculating peak value reduction value.

30. spread spectrum communication system as claimed in claim 29, wherein every grade peak value reduces the unit and also comprises combiner, is used to receive the peak value reduction value of calculating and they and incoming symbol are made up.

31. spread spectrum communication system as claimed in claim 30, wherein every grade peak value reduction unit also comprises delay circuit, the symbol that is used to delay time incoming symbol and time-delay is provided is to this combiner, so as in correct timing one by one symbol ground make up the symbol of peak value reduction value and time-delay.

32. spread spectrum communication system as claimed in claim 30, wherein said combiner comprises multiplier.

33. spread spectrum communication system as claimed in claim 30, wherein said combiner comprises adder.

34. a system that is used to reduce the peak signal output valve, this system are suitable for using in comprising the communication system of filter, this filter was providing symbol filtering before described communication system output signal, and this system comprises:

The filter predictor device, be used for utilize described filter carry out filtering before receiving symbol and the described filtering of prediction to the influence of described symbol; With

The symbol adjuster device is coupled to this filter predictor device, be used to regulate predicted will be after standing described filtering above the symbol of peak value limit value.

35. the system that is used to reduce the peak signal output valve as claimed in claim 34, wherein said filter has predetermined impulse response function, and wherein said filter predictor device comprises the device that is used for receiving the filter coefficient corresponding with described impulse response function on a plurality of sampled points.

36。The system that is used to reduce the peak signal output valve as claimed in claim 34, wherein said communication system are a kind of spread spectrum cellular communications system.

37. the system that is used to reduce the peak signal output valve as claimed in claim 34, the wherein said device that is used to regulate symbol comprises and is used to calculate the device of peak value reduction value and is used for device with peak value reduction value and described symbol combination.

38. the system that is used to reduce the peak signal output valve as claimed in claim 37, the wherein said device that is used to calculate comprises DSP.

39. the system that is used to reduce the peak signal output valve as claimed in claim 37, wherein said peak value reduction value comprises gain.

40. the system that is used to reduce the peak signal output valve as claimed in claim 37, the wherein said device that is used to make up comprises multiplier circuit.

41. the system that is used to reduce the peak signal output valve as claimed in claim 37, the wherein said device that is used to make up comprises addition or subtraction circuit.

42. the system that is used to reduce the peak signal output valve as claimed in claim 35, the wherein said device receiving filter coefficient on sampling timing and intersymbol sampling timing that is used for the receiving filter coefficient.

43. the system that is used to reduce the peak signal output valve as claimed in claim 35, the wherein said device receiving filter coefficient on a plurality of skew symbol sampler times that is used for the receiving filter coefficient.

44. the system that is used to reduce the peak signal output valve as claimed in claim 35, wherein said filter predictor device comprise a plurality of levels, every grade receives the different filtering output different filter coefficient regularly of expression.

45. the system that is used to reduce the peak signal output valve as claimed in claim 44 is wherein with the described level of serial mode configuration.

46. the system that is used to reduce the peak signal output valve as claimed in claim 44 is wherein with the described level of parallel mode configuration.

47. a method that is used to regulate value of symbol in comprising the communication system of filter, this filter was providing symbol filtering before described system output signal, and this method comprises:

Utilizing before described filter carries out filtering receiving symbol;

Adopt the known features of described filter to predict the influence of described filtering to described symbol; With

After standing described filtering, regulate predicted will be above the value of the symbol of peak value limit value, to reduce from the peak value of the signal of this system's output.

48. an improved spectrum spread communication method comprises:

Data symbol corresponding to the data channel of a plurality of separation of combining is provided;

Provide filtering operation according to the filter impulse response function; With

Carried out peak value and reduce processing before described filtering operation, described peak value reduces processing and comprises:

Utilize the filter coefficient value corresponding that the filtering output of prediction is provided with the filter impulse response function;

Receive filtering output and the predetermined filtering output limit value predicted, and determine peak value reduction value above the quantity of limit value according to the filtering output of prediction; With

With the combination of peak value reduction value and data symbol, and provide the adjusted symbol of peak value so that filtered and export by communication system.

49. improved spectrum spread communication method as claimed in claim 48 also is included in the sample rate that filtering increases data symbol before.

50. improved spectrum spread communication method as claimed in claim 49, wherein above sampling filter speed is carried out filtering to the data symbol of up-sampling.

51. improved spectrum spread communication method as claimed in claim 48, wherein this peak value reduces to handle and also comprises the delay data symbol, so that receive peak value reduction value and data symbol at described Assemble Duration on the mode of the time synchronized basis at symbol one by one.

52. improved spectrum spread communication method as claimed in claim 49, the wherein said filtering output that prediction is provided comprise receive with the corresponding first group of filter coefficient of the sample of the filter impulse response function at interval on the symbol and with second group of corresponding filter coefficient of sample of filter impulse response function on the intersymbol interval.

53. handling, improved spectrum spread communication method as claimed in claim 49, wherein said peak value reduction comprise that the peak value that provides based on timing on the symbol reduces processing and provides the peak value based on the intersymbol timing to reduce processing.

54. improved spectrum spread communication method as claimed in claim 48, wherein this combination comprises and multiplying each other, and wherein this peak value reduction value comprises a gain, and this gain provides an adjusted symbol when it and data symbol multiply each other, and this will produce the output signal that peak value reduces.

55. improved spectrum spread communication method as claimed in claim 48, wherein this combination comprises addition, and wherein this peak value reduction value comprises a value, this worthwhile it an adjusted symbol is provided when being added on this symbol, this will produce the output signal that peak value reduces.

56. improved spectrum spread communication method as claimed in claim 48, wherein said peak value reduce the value that processing also comprises the predictive filtering output that detects input, and value and the signal output peak value limit value that the predictive filtering of input is exported compared.

57. improved spectrum spread communication method as claimed in claim 56, wherein this peak value reduction processing also comprises: when only a value of exporting at the predictive filtering of input is exported the peak value limit value above signal, just allow output peak value reduction value so that make up.

58. improved spectrum spread communication method as claimed in claim 48, wherein this peak value reduction is handled and is comprised that also implementing peak value based on the filtering output of described limit value and prediction reduces algorithm.

59. improved spectrum spread communication method as claimed in claim 48 wherein saidly provides the data symbol corresponding to a plurality of data channels to comprise: the digital data channel that receives a plurality of separation; The spreading code of the digital data channel quantity that a plurality of different quantity equal to separate is provided; In the spreading code each is multiplied each other with one of digital data channel that separates, so that a plurality of spreading channels to be provided; And each spreading channel combined, to form the data symbol of combination.

60. an improved spectrum spread communication method comprises:

Reception is corresponding to the data symbol of the data channel of a plurality of separation of combining;

Increase the sampling rate of described symbol and the up-sampling symbol is provided;

Provide filtering operation according to the filter impulse response function, have a plurality of filter coefficients and corresponding with timing based on the sample rate of described increase; With

Providing peak value to reduce before the described filtering operation that adopts described data symbol handles, this peak value reduces to handle in a plurality of peak values reduction levels to be carried out, each peak value reduces to be handled level and comprises utilizing with the corresponding filter coefficient value of a part of filter impulse response function and come the influence of predictive filtering operation to the data symbol, so that the filtering output of prediction to be provided, and provide peak value to reduce to the filtering output of the prediction that surpasses the peak value limit value to handle, wherein said peak value reduces to handle to reduce at described multistage peak value provides the adjusted symbol of peak value after handling so that filtered and export.

61. improved spectrum spread communication method as claimed in claim 60 is wherein carried out described multistage peak value with serial mode and is reduced processing.

62. improved spectrum spread communication method as claimed in claim 60 is wherein carried out described multistage peak value with parallel mode and is reduced processing.

63. improved spectrum spread communication method as claimed in claim 60, wherein every grade of peak value reduction is handled and is adopted the up-sampling corresponding filter coefficient of timing slip regularly that departs from integer number with character rate.

64. improved spectrum spread communication method as claimed in claim 60, wherein every grade of peak value reduces the filtering output of handling to comprise the filter coefficient that reception is corresponding with the described part of filter impulse response function and described prediction is provided, and calculates peak value reduction value according to the filtering output of prediction.

65. as the described improved spectrum spread communication method of claim 64, wherein every grade of peak value reduces to handle and also comprises and receive the peak value reduction value calculated and they and incoming symbol are made up.

66. as the described improved spectrum spread communication method of claim 65, wherein every grade of peak value reduces and handles the symbol that also comprises the time-delay incoming symbol and the time-delay that will be combined is provided, so that the symbol of peak value reduction value and time-delay is being combined on the basis at symbol one by one in the correct timing.

67. as the described improved spectrum spread communication method of claim 65, wherein said combination comprises multiplies each other.

68. as the described improved spectrum spread communication method of claim 65, wherein said combination comprises addition.

Before the output communication signal, adopt the predetermined pulse response function to provide in the communication means of symbol filtering 69. a method that is used to reduce the peak signal output valve, this method are applicable to, comprising:

Receiving symbol before filtering, and use filter coefficient corresponding with described impulse response function on a plurality of sampled points predicted the influence of described filtering to described symbol; With

Regulate predicted will be after standing described filtering above the symbol of peak value limit value.

70. as the described method that is used to reduce the peak signal output valve of claim 69, wherein said communication means is the spread spectrum cellular communication method.

71., wherein regulate symbol and comprise calculating peak value reduction value and combination peak value reduction value and described symbol as the described method that is used to reduce the peak signal output valve of claim 69.

72. as the described method that is used to reduce the peak signal output valve of claim 71, wherein said peak value reduction value comprises a gain.

73. as the described method that is used to reduce the peak signal output valve of claim 72, wherein said combination comprises multiplies each other.

74. as the described method that is used to reduce the peak signal output valve of claim 71, wherein said combination comprises addition or subtracts each other.

75., wherein on sampling timing and intersymbol sampling timing, receive described filter coefficient as the described method that is used to reduce the peak signal output valve of claim 69.

76., wherein on a plurality of skew symbol sampler times, receive described filter coefficient as the described method that is used to reduce the peak signal output valve of claim 69.

77. as being used to reduce the method for peak signal output valve as described in the claim 69, wherein said prediction is carried out in multistage, every grade receives the different filtering output different filter coefficient regularly of expression.

78., wherein carry out described level with serial mode as the described method that is used to reduce the peak signal output valve of claim 77.

79., wherein carry out described level with parallel mode as the described method that is used to reduce the peak signal output valve of claim 77.

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