CN101356737A - Local oscillator leakage relocation - Google Patents
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- CN101356737A CN101356737A CNA2006800506093A CN200680050609A CN101356737A CN 101356737 A CN101356737 A CN 101356737A CN A2006800506093 A CNA2006800506093 A CN A2006800506093A CN 200680050609 A CN200680050609 A CN 200680050609A CN 101356737 A CN101356737 A CN 101356737A
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Abstract
An indication is received to relocate leakage in a transmission signal to be transmitted. A frequency change associated with relocating the leakage in the transmission signal is obtained. The leakage in the transmission signal is relocated based at least in part on the frequency change.
Description
Cross reference to other application
The priority of that the application requires to submit on November 7th, 2005, as to be entitled as " be used to detect and avoid local oscillator leakage relocation " U.S. Provisional Patent Application No 60/734,524, its content is all incorporated this paper by reference into and is used for all purposes.
Background technology
Ultra broadband (UWB) is a kind of wireless system that takies a large amount of frequency spectrums.For example, the frequency band of introducing in WiMedia UWB standard has the bandwidth of 508MHz.Sometimes other wireless system operates in this recess, UWB system and the shared wireless medium of other (for example, arrowband) wireless system by generate recess in UWB transmits.For example, some narrow-band wireless systems has about 1 to the bandwidth of 20MHz, then generates recess (for example, about 10 or 30Mhz wide) by the UWB system on the frequency spectrum that other wireless system moved in some cases.
A problem relevant with generating recess is from the leakage that operates in the local oscillator on the UWB carrier frequency (for example, the centre frequency of frequency band).The inhibition level that is used for the UWB system is being discussed by some European and/or Japanese management organizations, and it is lower than former inhibition level to other system requirements.Though the technology that may exist some to be used to remove or suppress local oscillator leakage (for example, technology for the narrowband systems exploitation), the degree that is enough to satisfy some requirement of advising be removed or be suppressed to these technology perhaps not necessarily can with local oscillator leakage.For example, this recess (it is added in the numeric field of being everlasting) may not reduce or remove local oscillator leakage, because it was added into afterwards.In analog domain, using filter may be inconvenient to remove local oscillator leakage, because this filter (for example must run on very high frequency, if use the carrier frequency of 3.96GHz, then run in the scope of 3.96GHz), and need very narrow so that the information on the side frequency is not removed.People expect to develop new technology and handle local oscillator leakage.
Description of drawings
Some embodiment of the present invention are disclosed in detailed introduction below and the respective drawings.
Fig. 1 is the schematic diagram of the embodiment that transmits of expression expectation.
Fig. 2 A is the schematic diagram that is illustrated in the embodiment that transmits that contains local oscillator leakage in the recess.
Fig. 2 B graphic representation has second embodiment that transmits of local oscillator leakage.
Fig. 3 is the schematic diagram that expression has the embodiment that transmits of the local oscillator leakage through being shifted.
Fig. 4 A is that expression is by the schematic diagram of the embodiment of the data-signal before the frequency displacement.
Fig. 4 B is that expression is by the schematic diagram of the embodiment of the data-signal after the frequency displacement.
Fig. 5 is the flow chart of embodiment of the method for expression displacement local oscillator leakage.
Fig. 6 A is the schematic diagram of the embodiment of the data in the frequency bin of IFFT before the expression frequency displacement
Fig. 6 B is that expression is by changing data are come the embodiment of frequency-shift data signal to the mapping of subcarrier schematic diagram in IFFT.
Fig. 7 is the schematic diagram of the embodiment of the expression transmitter that comprises the multiplier of the local oscillator leakage that is used to be shifted and adder
Embodiment
The present invention can be applied in every way, comprises as method, device, system, combination (a composition of matter), such as computer-readable recording medium or via the computer-readable mediums such as computer network of optics or the instruction of electronic communication link router.In this manual, these are used, and perhaps the present invention's any other form that can adopt can be called as technology.Be described as the parts that are set to carry out certain task such as processor or memory etc. and comprise that provisional configuration becomes to carry out the universal component of this task in preset time, or be manufactured into the special-purpose member of this task of execution.Generally speaking, the order of the step of disclosed method change within the scope of the invention.
The detailed introduction of one or more embodiment of the present invention is provided with the accompanying drawing of the expression principle of the invention below.Though introduce the present invention relatively with these embodiment, the present invention is not limited to any embodiment.Scope of the present invention only is defined by the claims, and the present invention comprised some optional, revise or the scheme of equivalence.Some specific details have been set forth in the introduction below, so that the present invention is comprehensively understood.These details provide for exemplary purposes, and the present invention can not comprise these part or all of specific detail according to claims enforcement.For the purpose of clear, do not describe technique known content in the affiliated technical field related to the present invention in detail, thicken not make the present invention unnecessaryly.
Fig. 1 is the schematic diagram of the embodiment that transmits of expression expectation.As shown in this example, the frequency band 2 of ultra broadband (UWB) system transmits and is illustrated.Transmitting of expectation 100 has the bandwidth of 508MHz.For example, transmitting of expectation 100 can be generated by the WiMedia wireless system, and this system's midband has the width of 508MHz.In certain embodiments, use other UWB system (for example, the system beyond the WiMedia) and/or the bandwidth (for example, the bandwidth beyond the 508MHz) that transmits and have other.100 the carrier frequency (being the centre frequency of frequency band) of transmitting of expectation is 3.96GHz.
In this example, transmitting of expectation 100 comprises that 20MHz is wide and is centered close to the recess 102 of 3.96GHz.Recess is a part that transmits, and it is attenuated or suppresses, and is not used to exchange message in some cases.For example, wireless system may detect other wireless systems in the frequency range of recess 102, and generates recess 102 to prevent and other wireless system produces and disturbs.Can use any suitable technique and in transmitting, generate recess.In certain embodiments, in numeric field, generate recess by in the suitable frequency bin of invert fast fourier transformation (IFFT), inserting zero.For example, some transmitting set has the IFFT of data from the frequency domain transform to the time domain.Some execution or the wireless system that meets WiMedia UWB standard can comprise 128 IFFT.Each frequency bin is corresponding to a characteristic frequency, and then zero (or other suitable value) is inserted into those frequency bins corresponding to recess.
In certain embodiments, management organization require to recess carry out to a certain degree decay or inhibition (for example, so that with expectation transmit 100 relevant wireless systems not with the frequency range that operates in recess 102 in other wireless system disturb).For example, the potential interference on some narrowband systems (as WiMax) that some Japan and/or European management organization's worry are caused by the UWB system is because the UWB system has as a little big bandwidth (as 508MHz).The maximum UWB signal level of advising in recess in some cases is-70dBm/MHz.
Although expectation obtains to transmit 100, may produce or generate transmitting of other, for example as the result of local oscillator leakage by wireless system.Following accompanying drawing illustrates two examples.
Fig. 2 A is the schematic diagram that is illustrated in the embodiment that transmits that contains local oscillator leakage in the recess.As shown in this example, concerning wireless system, require or expect be emission expectation transmit 100,200 may be the signal of actual generation but transmit.The same with the example of Fig. 1, transmitting 200 has the bandwidth of 508MHz, and recess 204 has the bandwidth of 20MHz.Yet recess 204 comprises local oscillator leakage 202.The frequency of local oscillator leakage 202 appears on the carrier frequency that is generated by local oscillator (for example, the centre frequency of frequency band, it is 3.96GHz in this example).In certain embodiments, carrier frequency also is on other the frequency (for example, because use other frequency band or a frequency band to have other centre frequency) except that 3.96GHz, and then local oscillator leakage 202 appears on those frequencies.Local oscillator leakage 202 can take place in the input of quadrature modulator (for example) and/or the leakage paths from local oscillator to an output because the DC component.
Because local oscillator leakage 202, the signal level relevant that the signal level of recess 204 or inhibitions degree may surpass desired or requirement with recess 204.For example, local oscillator leakage 202 may be bigger than the degree of decay of being set by certain management organization.In some cases, can not reach the wireless system that management organization requires does not allow to sell in this country and/or use.
Fig. 2 B represents to have second embodiment that transmits of local oscillator leakage.The example class of Fig. 2 B is similar to the example shown in Fig. 2 A, is not impulse function except local oscillator leakage 250 but has associated certain bandwidth.In some cases, than the example of Fig. 2 A, local oscillator leakage may more approach the example of Fig. 2 B.For example, if wireless system runs on frequency band frequency hopping mode, wherein logic channel comprises a plurality of frequency bands (being hop bands), and than the example of Fig. 2 A, local oscillator leakage may more approach the example of Fig. 2 B.In some cases, local oscillator leakage 250 contributes to signal substrate (floor) or otherwise raises the signal level of recess 252.
Be intended to illustrate in relevant frequency and/or the signal level shown in these accompanying drawings and/or other accompanying drawing.In some cases, local oscillator leakage have with here shown in different signal level, shape and/or the width of example.For example, local oscillator leakage may have than the relevant high signal level that transmits in some cases.In some cases, recess may comprise carrier frequency or overlapping with carrier frequency, but carrier frequency may not necessarily appear at the center (that is the relative recess off-center of carrier frequency possibility) of this recess.
Under the situation of UWB, the transmission signal level outside the recess 252 may be-41.3dBm/MHz.Thereby the total transmitting power of UWB is-9.5dBm (41.3dBm/MHz+10*log when frequency hopping in 3 frequency band modes
10(508)+10*log
10(3)).In order to reach-requirement of 70dBm, signal and LO leakage ratio must be higher than 60.5dB.High like this signal and LO ratio, can not reach with the method for designing of routine the requirement of other wireless system far above before.Disclosed herein is a kind of method (for example, make the local oscillator leakage that is shifted no longer be in the recess, thereby can satisfy the requirement of management organization) of the local oscillator leakage that is shifted.Next description of drawings is the embodiment that is shifted of local oscillator leakage wherein.
Fig. 3 is the schematic diagram of the embodiment that transmits that expression has the local oscillator leakage of displacement.As shown in this example, transmit and 300 have bandwidth (be 508MHz) identical and identical carrier frequency (being 3.96GHz) with the example shown in Fig. 2 A and the 2B.Yet local oscillator leakage 302 has been shifted, and is positioned at 3.95GHz rather than 3.96GHz.In other words, this local oscillator leakage is shifted and no longer is positioned at recess 304, does not contribute to the signal level of recess 304.In this example, for the purpose of explanation, local oscillator leakage 302 is shown having with identical with respect to transmitting 300 upright position shown in Fig. 2 A.In some cases, the local oscillator leakage of displacement contributes to the signal level that transmits, and causes the rising in the signal level of appropriate frequency (as 3.95GHz).
In different embodiment, local oscillator leakage is shifted or moves different amounts.In this example, the local oscillator leakage 302 of displacement is positioned at the edge of recess 304.In the displacement of some embodiment, some nargin are counted frequency domain (for example, making the local oscillator leakage of this displacement not be positioned at the edge of recess).For example, if than Fig. 2 A, the shape of local oscillator leakage more approaches the example among Fig. 2 B, then preferably has some nargin so that the signal level of the local oscillator leakage of displacement descends before the edge of recess.In some cases, the accurate shape or the bandwidth of local oscillator leakage are difficult to measure, thereby adopt some nargin.
In certain embodiments, local oscillator leakage is to other direction superior displacement (for example, being displaced on the higher frequency on recess 304 right sides).In certain embodiments, local oscillator leakage is shifted, and (for example, is displaced to frequency that is lower than 3.706GHz or the frequency that is higher than 4.214GHz in this example) to be located at outside the frequency spectrum that transmits.
Leakage displacement with local oscillator may be attractive in some applications, because just needn't require to use custom-designed receiver like this.For example, receiver can necessarily need be known to transmit and comprises the local oscillator signals that has been shifted this transmits so that receiver can suitably receive and/or decode.
In certain embodiments, with the degree of decay that local oscillator leakage relocation and one or more technology combine and reach be associated with recess desired or require, performance of improvement or the like.For example, in certain embodiments, local oscillator relocation and (further) reduced or the technology of the signal level of decay recess combines.In certain embodiments, the displacement with local oscillator leakage combines with the technology that suppresses local oscillator leakage.
Disclosed technology can be used together with the different transmitters among the different embodiment in the literary composition.For example, some wireless system comprises the Direct Conversion transmitter.The Direct Conversion transmitter is a kind of (being the center with DC or zero frequency promptly) data-signal on the base band frequency to be converted directly to the transmitter that broadcasting or tranmitting frequency need not earlier data-signal to be converted to intermediate-freuqncy signal.In certain embodiments, use other type transmitter (for example, MF transmitter, use near or mainly be positioned at the nearly Direct Conversion transmitter of the data-signal on the DC, or the like).Can use any suitable transmitter.
In certain embodiments, use the displacement of local oscillator leakage for frequency band frequency-hopping radio system (band hopping wirelesssystem).In the example of a frequency band frequency hopping, logic channel comprises frequency band 1,2 and 3, and this wireless system circulates in these frequency bands with the frequency hop sequence of a repetition or pattern (for example, frequency band 1,3, then 2).The frequency band of forming a logic channel is called as hop bands sometimes.Can adopt the hop bands of any amount, any frequency hop sequence, and/or any frequency hop sequence length.In certain embodiments, the frequency band frequency hopping is also referred to as time-frequency and interweaves (Time Frequency Interleaving:TFI), and uses an independent frequency band to be called as fixed frequency interweave (Fixed FrequencyInterleaving:FFI).In certain embodiments, use the technology of introducing here for the frequency band frequency-hopping system.For example, one or more hop bands of logic channel can have with transmit in the overlapping carrier frequency of recess, and local oscillator leakage is shifted.In certain embodiments, use local oscillator leakage relocation for the system that runs on the fixed frequency interlace mode.
Although some embodiment that introduces in the literary composition has discussed wireless system, in certain embodiments, disclosed technology can be used for wired system in the literary composition.For example, can be processed via cable or transmitting of other wire medium transmission, so that local oscillator leakage is shifted.
In certain embodiments, by with suitable amount frequency-shift data signal and will through the data-signal of frequency displacement with correspondingly the displacement (for example, frequency displacement for the offset data signal) local oscillated signal merges, and obtains to have to transmit 100 through the local oscillator leakage of displacement.Following accompanying drawing is represented the example with the data-signal frequency displacement.
Fig. 4 A is that expression is by the schematic diagram of the embodiment of the data-signal before the frequency displacement.As shown in this example, data-signal 400 is positioned at baseband frequency range (that is being the center with frequency 0) and has the bandwidth of 508MHz.Recess 402 is wide and be the center with frequency 0 for 20MHz.In this example, data-signal 400 corresponding to operate in that local oscillator on the carrier frequency merges or mixing before in emission process or the path a bit.
Fig. 4 B is the schematic diagram of expression through the embodiment of the data-signal of frequency displacement.As shown in this example, the data-signal 400 among Fig. 4 A on frequency to upshift (promptly moving right) 10MHz.Perhaps, in certain embodiments, data-signal is moved down on frequency.Fig. 4 A illustrates the frequency displacement that identical x axle illustrates data-signal with 4B.Notice that data-signal 450 and recess 452 have width and the shape identical with data-signal 400 and recess 402 respectively, but exceed 10MHz.In this example, illustrate transmit 300 frequency-shift data signal of generation, and this data-signal is by frequency displacement 10MHz.In certain embodiments, expect other displacement, and data-signal is changed correspondingly by the amount of frequency displacement and/or direction.
The local oscillator that runs on carrier frequency is adjusted by corresponding amount (not shown).For example, running on local oscillator on the carrier frequency of 3.96GHz is adjusted to and runs on 3.95GHz (that is, 3.96GHz-10MHz) with the data-signal 450 of coupling through displacement.The local oscillated signal of this 3.95GHz merges to obtain transmitting 300 shown in Fig. 3 with data-signal 450 through displacement then.On the contrary, in the embodiment of data-signal displacement downwards, local oscillated signal can be increased suitable amount and merge with data-signal to downshift.In such embodiments, local oscillator leakage can be on frequency upward displacement and be located at the right side of recess.
Fig. 5 is expression be used for the being shifted flow chart of embodiment of method of local oscillator leakage.As shown in this example, the recess in transmitting comprises or is overlapped in the carrier frequency that transmits, and local oscillator leakage is shifted so that it is not within the frequency range of this recess.
In step 500, receive indication and the displacement local oscillator leakage.For example, some wireless system has detection and/or avoidance module, and it detects the existence of other wireless system.In certain embodiments, when another wireless system on the frequency spectrum that operates in the carrier frequency that comprises transmitting wireless system is detected, receive a signal from detection and/or avoidance module.
In step 502, determine the suitable shift amount of local oscillator leakage.For example, can obtain frequency range (for example, the f of recess or inhibition part
LowOr f
High), can obtain carrier frequency (for example, f
Carrier), and deduct suitable amount (for example, f
Carrier-f
LowOr f
High-f
Carrier).In certain embodiments, this leakage is not an impulse function, then considers the width of this leakage.In certain embodiments, add some nargin.In certain embodiments, with the predetermined unit local oscillator leakage that moves or be shifted.For example, in some cases, be that single-place shift leaks with 4.125MHz.In certain embodiments, the characteristic frequency or the signal that use in the displacement local oscillator leakage can obtain from existing parts, thereby then use these frequencies or signal not to need optional feature.In certain embodiments, the amount of Que Dinging is just comprising/negative sign or direction (for example, frequency be shifted downward or upward local oscillator leakage).In certain embodiments, leak with predetermined or fixing amount frequency shift local oscillator.
In step 504, based on the data-signal of amount frequency displacement on baseband frequency range of determining.In certain embodiments, based on determine in step 502 just/negative sign and/or value frequency-shift data signal.For example, an example of Fig. 4 A and 4B explanation frequency-shift data signal.In step 506, based on the amount displaced carrier signal of determining.In certain embodiments, if in step 504 on frequency downward frequency-shift data signal, the local oscillator of adjusting in step 506 increases identical amount on frequency.
In step 508, the data-signal of frequency displacement and the carrier signal of frequency displacement are obtained to have transmitting of displacement carrier leak by merging.For example, use the Direct Conversion transmitter in certain embodiments.In certain embodiments, use the transmitter of other type.Transmitting is included in it by suitable additional treatments before the wireless transmission, as filtering, amplification or the like.In certain embodiments, downstream or follow-up processing are suitably revised or are adjusted so that the processing relevant with the displacement of local oscillator leakage to be provided.For example, some transmitter comprises one or more filters, with the carrier signal mixing before with data-signal filtering.In certain embodiments, these filters are adjusted to hold in the step 504 frequency displacement (for example, holding wideer base band frequency) to data-signal.If desired, can carry out other change or correction to downstream or follow-up processing.
In different embodiment, use diverse ways to come the frequency-shift data signal in step 504.The embodiment of following two data-signal frequency displacements of description of drawings.In certain embodiments, the data relevant with subcarrier or frequency bin are by frequency displacement, for example at the input of inverse fast Fourier transform (IFFT).In certain embodiments, use multiplier and adder to come the frequency-shift data signal.
Fig. 6 A is the schematic diagram of the embodiment of the data in the frequency bin of IFFT before the expression frequency displacement.As shown in this example, IFFT has 128 frequency bins, numbering from-63 to 64 shown in.IFFT is a parallel processing apparatus, and it receives the frequency bin of N equal intervals and exports suitable time-domain signal.Frequency bin is also referred to as subcarrier.
This IFFT goes up process data signal at baseband frequency range (being the center with frequency 0 promptly).Subcarrier 0 respective frequencies 0, the corresponding negative frequency of negative subcarrier, the frequency that positive subcarrier is corresponding positive.WiMedia UWB specification description the function and application relevant with specific subcarrier.Subcarrier-63 is configured to 0 to-62 and 62 to 64, to generate the protection frequency band between the frequency band.Subcarrier-61 is to-57 and 57 to 61 being user definition frequency bins, and correspond respectively to from-251.625MHz to-235.125MHz and the frequency range from 235.125MHz to 251.625MHz.In this example, these subcarriers are as transition gap.For example, transmit on signal strength signal intensity to-61 and 57 to 61 from subcarrier-57 and reduce gradually.Suitable value can be passed in the frequency bin of these IFFT, as 0.
Subcarrier-56 to 56 (not comprising subcarrier 0) corresponding to-231MHz frequency to 231MHz, and be used to carry payload data or pilot tone storehouse (pilotbin).Data are passed to or are associated with suitable subcarrier.For example, data D-56 is associated with subcarrier-56, and data-55 are associated with subcarrier-55, or the like.In certain embodiments, data transmitted or be mapped to other subcarrier with the frequency-shift data signal.
Following example of description of drawings.
Fig. 6 B is that expression is by changing data are come the embodiment of frequency-shift data signal to the mapping of subcarrier schematic diagram in IFFT.In this example, every data (from the state shown in Fig. 6 A) three frequency bins of frequency displacement to the right (promptly moving up) in frequency.For example, data D-56 is passed to subcarrier-53, and data D-55 is passed to subcarrier-52, or the like.In this example, 0 value is passed to subcarrier-63 to-61, and these subcarriers are exposed by frequency displacement.In certain embodiments, other value is passed to the subcarrier that is exposed by frequency displacement beyond 0.
In this example, use WiMedia UWB standard, IFFT is relevant with the 528MHz bandwidth.Because 128 subcarriers are arranged, each subcarrier is divided with 4.125MHz (being 528MHz/128).Use the method, data-signal is the unit frequency displacement with 4.125Mhz.Therefore, if wish local oscillated signal displacement (for example) 10MHz is at least needed to move the subcarrier more than three.With the frequency displacement of three subcarriers of data shift corresponding to 12.375MHz, this is greater than the displacement of the 10MHz of expectation or requirement in this example.In certain embodiments, use other IFFT (for example, 64 IFFT, 256 IFFT etc.), and/or other value beyond IFFT and the 528MHz is relevant, and calculating is correspondingly revised.In certain embodiments, data are assigned with or are mapped to lower subcarrier (promptly be moved to the left or on frequency to downshift), perhaps are moved the subcarrier of other quantity beyond 3.
In certain embodiments, the data mode of being lost with some data is mapped to subcarrier.For example, 9 subcarriers if data move up on frequency, then data D+56 is lost, and data D+55 is passed to subcarrier 64, and data D+54 is passed to subcarrier 63, or the like.In some applications, losing some data is acceptables, because wireless system comprises coding or alignment technique, although some loss of datas still may provide acceptable performance level.For example coding or alignment technique comprise replicator (for example, the OFDM symbol), error correction coding or the like.In certain embodiments, these codings or alignment technique are in standard or standard, as WiMedia UWB standard.
Owing to multiple reason, it may be attractive that the mapping that is delivered to the data of IFFT by change comes the embodiment of frequency-shift data signal.In certain embodiments, these embodiment are achieved and do not need very big design complexity, cost etc.For example, less relatively and/or simple numerical logical circuit can be connected to the input of IFFT.This piece logical circuit can change the mapping of data to subcarrier.For example, when running on the following time of normal mode that local oscillator leakage is not shifted, use the mapping shown in Fig. 6 A; When running on leakage relocation mode, use the mapping shown in Fig. 6 B.
Fig. 7 is expression be used to the to be shifted schematic diagram of embodiment of the transmitter that comprises multiplier and adder of local oscillator leakage.As shown in this example, the centre frequency of frequency band is positioned at 3.96GHz, and wishes with local oscillator leakage relocation 10MHz (for example, because recess 20MHz is wide, and should leakage can be positioned at the center of this recess if be not shifted then).In certain embodiments, but also comprise other parts outside the transmitter implementation illustrated here parts, perhaps the exemplary components shown in the conduct here substitutes.
Two time-domain signals of IFFT 700 outputs, I and Q, they pass to sampler 702 and 704 respectively.In this example, digital to analog converter (DAC) 706 and 708 is operated on the sampling rate that doubles IFFT 700, and sampler is used for holding this sampling rate on these.
The I of last sampling and Q signal are sent to frequency shifter 710.In this example, frequency shifter 710 reception data-signals (for example, being centered close to zero frequency) and output are through the data-signal of frequency displacement.Frequency shifter 710 comprises multiplier 712,714,716 and 718.I or the Q signal of transmitting a 10MHz for each multiplier, for example these signal phases differ 90 degree each other.Multiplier 712 and 718 output value of real part, these value of real part are by adder 720 additions.Correspondingly, multiplier 714 and 716 output imaginary values and added together by adder 722.If expect other shift amount, can transmit different frequencies with 718 to multiplier 712,714,716.Similarly, if want to obtain local oscillator leakage relocation on other direction, then can pass to I and the Q signal exchange of the 10MHz of multiplier.
I and Q signal through displacement are sent to DAC 706 and 708 then.The I and the Q signal of simulation carry out filtering by filter 724 and 728 then.In certain embodiments, filter 724 and 728 is suitably adjusted to hold the wideer bandwidth that causes because of frequency displacement.Filtered signal mixes with I and the Q signal of 3.95GHz with frequency mixer 730 and 732 then, and merges with adder 734.
In this example, specific frequency is shown to be illustrated more clearly in this example.Local oscillator leakage in certain embodiments, uses configurable parts, so that can be displaced to one in a plurality of transposition frequencies.For example, in certain embodiments, configurable local oscillator or other frequency generator are connected to multiplier 712,714,716 and 718.Can use any appropriate signal generator.
In some applications, preferably use multiplier to come the frequency-shift data signal.For example, the frequency displacement that allows can be unrestricted, perhaps the embodiment before the comparability (wherein local oscillator leakage is with multiple or the displacement of other increment of 4.125MHz, and this increment depends on for example employed IFFT (as 128 IFFT) and/or the bandwidth (as 528MHz) relevant with IFFT etc.) has trickleer frequency displacement interval degree.Another reason of using multiplier approach is this meeting reduced data current control, and its cost is the increase of gate circuit quantity and current drain.
Following equation has been described the displacement of local oscillator leakage with mathematical way.RF signal (promptly transmitting) on the antenna can be defined as:
RF＝I*cos(w
0*t)+Q*sin(w
0*t)+L*cos(w
0*t+p)
W wherein
0Be the centre frequency of frequency band, and L and p represent level and phase place that LO leaks.
Following formula can be rewritten into:
RF＝real[(I+j*Q+k)*exp(j*w
0*t)]
Wherein I+j*Q is called complex baseband signal, and k is the plural number that leaks of analog carrier (as, constant).
For fear of comprising w with being operated in
0Frequency band (for example, comprise this carrier frequency w
0Recess) on other wireless system disturb, thereby this frequency shift is made it outside this scope.New frequency w
1Be defined as:
w
1=w
0+ dw, wherein dw is frequency shift or shift amount.
Obtain from following formula:
exp(w
1*t)＝exp(w
0*t)*exp(dw*t)
For this RF signal is remained on identical frequency, new I ' and Q ' signal (the equation simplification being obtained by k being set to 0) are:
RF＝real[(I+j*Q)*exp(j*w
0*t)]
＝real[(I′+j*Q′)*exp(j*w
1*t)]
＝real[(I′+j*Q′)*exp(j*w
0*t)*exp(j*dw*t)]
Thereby new in certain embodiments complex baseband signal is:
I′+j*Q′＝(I+j*Q)exp(-j*dw*t)
Though, introduced the embodiment of front, these details that the invention is not restricted to provide with some details for the clear purpose of understanding.Has a lot of enforcements replacement scheme of the present invention.Disclosed embodiment be the example effect and non-limiting effect.
Claims (24)
1. one kind will leak the method that is shifted, and comprise:
Receive indication and displacement will be launched in transmitting leakage;
Obtain with described transmitting in the relevant frequency shift of displacement of leakage; And
At least in part based on be shifted leakage in described the transmitting of described frequency shift.
2. method according to claim 1, wherein, described transmitting comprises wireless transmission signal.
3. method according to claim 1, wherein, described transmitting also comprises the inhibition part, and described inhibition part will be overlapping with described leakage on frequency when supposing that described leakage is not shifted
4. method according to claim 3, wherein, the described frequency range that suppresses part is used by another wireless system.
5. method according to claim 1, wherein, described obtaining comprises and obtains predetermined frequency shift.
6. method according to claim 3, wherein, the described frequency range that comprises this leakage when supposing that with (2) described leakage is not shifted based on (1) described frequency range that suppresses part at least in part of obtaining is determined described frequency shift.
7. method according to claim 6 is wherein also determined described frequency shift based on the frequency shift of (3) one or more permissions at least in part.
8. method according to claim 1, wherein, described transmit relevant with ultra broadband (UWB).
9. method according to claim 1, wherein, described transmit relevant with WiMedia ultra broadband (UWB) standard.
10. method according to claim 1, wherein, described transmit relevant with the frequency band frequency hopping.
11. method according to claim 1, wherein, described frequency shift is just comprising/negative sign.
12. method according to claim 1, wherein, described displacement comprises:
Come the frequency-shift data signal based on described frequency shift at least in part;
Come the displaced carrier signal based on described frequency shift at least in part; And
To merge through the data-signal of frequency displacement with through the carrier signal of frequency displacement.
13. method according to claim 12, wherein, if described data-signal on frequency to the described frequency shift of upshift, then described carrier signal on frequency to the described frequency shift of downshift.
14. method according to claim 12, wherein, the described data-signal of frequency displacement comprises at least one multiplier of use.
15. method according to claim 12, wherein, the frequency displacement of described data-signal comprises the mapping of change from data to one or more subcarriers relevant with inverse fast Fourier transform (IFFT).
16. method according to claim 12, wherein, described displacement also is included in through the data-signal of frequency displacement with before the carrier signal of frequency displacement merges, and just adjusts the relevant filter of filtering with described data-signal through frequency displacement if desired.
17. a system that is used to be shifted and leaks comprises:
Be configured to receive indication and the interface of the leakage that displacement will be launched in transmitting; And
Signal processor is configured to
Can obtain with described transmitting in the relevant frequency shift of displacement of leakage; And
Can be at least in part based on be shifted leakage in described the transmitting of described frequency shift.
18. system according to claim 17, wherein, described transmitting also comprises the inhibition part, and described inhibition part will be overlapping with described leakage on frequency when supposing that described leakage is not shifted.
19. system according to claim 18, wherein, described signal processor is configured to when suppose that based on (1) described frequency range that suppresses part and (2) described leakage is not shifted at least in part frequency range of leakage and determines that described frequency shift obtains.
20. system according to claim 19, wherein, described signal processor is configured to also determine described frequency shift based on the frequency shift of (3) one or more permissions at least in part.
21. system according to claim 17, wherein, described signal processor is configured to be shifted according to the following steps:
Come the frequency-shift data signal based on described frequency shift at least in part;
Come the displaced carrier signal based on described frequency shift at least in part; And
Merging is through the data-signal of frequency displacement with through the carrier signal of frequency displacement.
22. system according to claim 21, wherein, described signal processor is configured to by using at least one multiplier to come the described data-signal of frequency displacement.
23. system according to claim 21, wherein, described signal processor is configured to come the described data-signal of frequency displacement by the mapping that changes from data to one or more subcarriers relevant with inverse fast Fourier transform (IFFT).
24. a computer program that is used to be shifted and leaks, described computer program is included in the computer-readable medium, and comprises following computer instruction:
Receive indication and displacement will be launched in transmitting leakage;
Obtain with described transmitting in the relevant frequency shift of displacement of leakage; And
At least in part based on be shifted leakage in described the transmitting of described frequency shift
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| US73452405P | 2005-11-07 | 2005-11-07 | |
| US60/734,524 | 2005-11-07 | ||
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101604984A (en) * | 2009-05-31 | 2009-12-16 | 复旦大学 | A kind of ultra-broadband emitter and method for designing thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101604984A (en) * | 2009-05-31 | 2009-12-16 | 复旦大学 | A kind of ultra-broadband emitter and method for designing thereof |
| CN101604984B (en) * | 2009-05-31 | 2013-01-30 | 复旦大学 | Ultra-wide band transmitter and design method thereof |
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