CN104144140A - Method for reducing peak-to-average ratio in OFDM system and access device - Google Patents
Method for reducing peak-to-average ratio in OFDM system and access device Download PDFInfo
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Abstract
The invention relates to a method for reducing a peak-to-average ratio in an OFDM system. The method comprises the steps that (1) fast inverse Fourier transform is carried out on modulating signals needing to the sent to obtain a first time-domain signal set; (2) the first time-domain signal set is searched for a plurality of time-domain signals with the power meeting the threshold and the time-domain positions, obtained when the power is maximum, of the time-domain signals; (3) auxiliary frequency-domain signals are sent in a determined subcarrier, inverse adjustment is carried out on second time-domain signals at the time-domain positions, obtained when the power of first time-domain signals is maximum, of the auxiliary signals, and the first time-domain signals are the signals, with the maximum power, of the multiple time-domain signals; (4) the second time-domain signals of the adjusted auxiliary signals and the first time-domain signals are added so as to reduce the peak-to-average ratio of the modulating signals. According to the method, the peak-to-average ratio of the modulating signals in the OFDM system under the situation of low power consumption and operands can be reduced.
Description
Technical field
The present invention relates to the communications field, be specifically related to a kind of method and access device of reducing PAR of OFDM system.
Background technology
WLAN (wireless local area network) (Wireless Local Area Network, WLAN) technology has advantages of two-forty access, at mobile network's access field, is widely used.In WLAN technology, Orthodoxy Frequency Division Multiplex (Orthogonal Frequency Division Multiplexing, OFDM) technology, but peak-to-average power ratio (the Peak to Average Power Ratio due to PFDM, PAPR) larger, to power amplifier, (linearity of (power amplifier, PA) requires to exert an influence, and therefore need to reduce the PAPR of WLAN (wireless local area network) ofdm system.
In prior art, the method for reduction PAPR is a kind of is to adopt the method remapping.Exhaustive search is carried out in any combination by bit corresponding to each symbol in transmitted signal, finds therein a kind of bit combination of PAPR minimum.Therefore,, for exhaustive every kind of bit combination, need very large system power dissipation, and, bit combination in the complete the best of each symbol search only has, and needs the indication information that each symbol is transmitted in sending point just can make receiving terminal be correctly decoded, and this has also increased the consumption to resource.
The another kind of method that reduces PAPR is, the amplitude of different pilot signals and angle are adjusted, each pilot signal after adjusting is carried out IFFT conversion, obtain a time-domain signal set, each time-domain signal in time-domain signal set and transmitted signal are carried out after the time-domain signal addition after IFFT conversion, obtain corresponding PAPR, in time-domain signal set, choose the pilot signal corresponding to peak-to-average force ratio of PAPR minimum and carry out data transmission.The shortcoming of this kind of scheme is, due to pilot tone, candidate is larger in conjunction with number, needs the whole pilot signals in traversal set, and amount of calculation is larger.
Summary of the invention
The embodiment of the present invention provides a kind of method of reducing PAR of OFDM system, with realize reduce ofdm system lower power consumption and the operand in the situation that in the peak-to-average force ratio of modulation signal.
Embodiment of the present invention first aspect provides a kind of method of reducing PAR of OFDM system, and described method comprises:
Step 1, the frequency domain symbol signal that needs are sent carries out inverse fast Fourier transform, obtains the first time-domain signal sequence;
Step 2 is searched over the time-domain signal of power threshold and the time-domain position of described time-domain signal in described the first time-domain signal sequence;
Step 3, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Step 4, is added described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
Based on first aspect, in the possible execution mode of the first, after described step 4, also comprise:
Step 5, whether the described peak-to-average force ratio after detection reduces meets is set thresholding, in the situation that not meeting setting thresholding, uses another frequency domain auxiliary signal, and perform step 3 to step 5, until described peak-to-average force ratio meets, set thresholding or there is no available frequency domain auxiliary signal.
Based on first aspect or the possible execution mode of the first, in the possible execution mode of the second, described frequency domain auxiliary signal is pilot signal or the signal for reducing peak-to-average force ratio that sends in idle sub-carrier.
In the possible execution mode of the execution mode that the first based on first aspect is possible or the second, in the third possible execution mode, in described step 3, described frequency domain auxiliary signal is adjusted, comprised frequency domain adjustment, described method of adjustment is, frequency-region signal to the subcarrier of described frequency domain auxiliary signal is multiplied by exp(-j*2pi*K/Nc*T), wherein, K is described sub-carrier positions, and described T is that described the first time-domain signal is at the time-domain position of time domain maximum power.
Possible execution mode or the possible execution mode of the second of the first based on first aspect, in the 4th kind of possible execution mode, described frequency domain auxiliary signal is adjusted, comprise time domain adjustment, described method of adjustment is, according to order from left to right, according to described the first time-domain signal, at time-domain position T, time-domain signal corresponding to described frequency domain auxiliary signal after inverse fast Fourier transform carried out to cyclic shift T to the right.
In the possible execution mode of the execution mode that the first based on first aspect is possible or the second or the third possible execution mode or the 4th kind of possible execution mode, in the 5th kind of possible execution mode, the described time-domain signal that surpasses power threshold is specially prominent time-domain signal in described the first time-domain signal sequence.
In the possible execution mode of the execution mode that the first based on first aspect is possible or the second or the third possible execution mode or the 4th kind of possible execution mode, in the 5th kind of possible execution mode, the described time-domain signal that surpasses power threshold is specially the time-domain signal of real part maximum in described the first time-domain signal sequence.
In the possible execution mode of the execution mode that the first based on first aspect is possible or the second or the third possible execution mode or the 4th kind of possible execution mode, in the 5th kind of possible execution mode, the described time-domain signal that surpasses power threshold is specially the time-domain signal of imaginary part maximum in described the first time-domain signal sequence.
Second aspect, the embodiment of the present invention provides the access device in a kind of WLAN (wireless local area network), and described access device comprises:
Converter unit, carries out inverse fast Fourier transform for the frequency domain symbol signal that needs are sent, and obtains the first time-domain signal arrangement set;
Search unit, for described the first time-domain signal sequence, search over the time-domain signal of power threshold and the time-domain position of described time-domain signal;
Processing unit, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Arithmetic element, in order to described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence are added, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
Based on second aspect, in the possible execution mode of the first, also comprise performance element, whether the described peak-to-average force ratio detecting after reducing meets setting thresholding, in the situation that not meeting setting thresholding, control described processing unit and described arithmetic element repeats, use another frequency domain auxiliary signal, until described peak-to-average force ratio meets, set thresholding or there is no available frequency domain auxiliary signal.
Based on second aspect or the possible execution mode of the first, in the possible execution mode of the second, described frequency domain auxiliary signal is pilot tone or the signal for reducing peak-to-average force ratio that sends in idle sub-carrier.
Possible execution mode or the possible execution mode of the second of the first based on second aspect, in the third possible execution mode, described processing unit is adjusted described frequency domain auxiliary signal, comprise frequency domain adjustment, described method of adjustment is that the frequency-region signal of the subcarrier of described auxiliary signal is multiplied by exp(-j*2pi*K/Nc*T), wherein, K is described sub-carrier positions, and described T is that described the first time-domain signal is in the position of time domain maximum power.
Possible execution mode or the possible execution mode of the second of the first based on second aspect, in the 4th kind of possible execution mode, described processing unit is adjusted described frequency domain auxiliary signal, be specially frequency domain adjustment, described method of adjustment is, according to order from left to right, according to described the first time-domain signal, at the position of time domain maximum power T, the time-domain signal of the auxiliary signal after inverse fast Fourier transform is carried out to cyclic shift T to the right.
In the possible execution mode of the execution mode that the first based on second aspect is possible or the second or the third possible execution mode or the 4th kind of possible execution mode, in the 5th kind of possible execution mode, the described time-domain signal that surpasses power threshold is specially prominent time-domain signal in described the first time-domain signal sequence.
In the possible execution mode of the execution mode that the first based on second aspect is possible or the second or the third possible execution mode or the 4th kind of possible execution mode, in the 5th kind of possible execution mode, the described time-domain signal that surpasses power threshold is specially the time-domain signal of real part maximum in described the first time-domain signal sequence.
In the possible execution mode of the execution mode that the first based on second aspect is possible or the second or the third possible execution mode or the 4th kind of possible execution mode, in the 5th kind of possible execution mode, the described time-domain signal that surpasses power threshold is specially the time-domain signal of imaginary part maximum in described the first time-domain signal sequence.
The embodiment of the present invention provides a kind of method of reducing PAR of OFDM system, by in the poor idle sub-carrier of signal to noise ratio, send reference signal as auxiliary signal or in the situation that not needing channel estimating using pilot signal as auxiliary signal, and adjust the phase place of auxiliary signal, maximum time-domain signal stack in the modulation signal that the reverse maximum of auxiliary signal and needs are sent, in and the method for modulation signal time domain power, reduce the peak-to-average force ratio of adjusting signal in ofdm system, the computation complexity of can also demoting, improves signal treatment effeciency.
Accompanying drawing explanation
The flow chart of the method for the reducing PAR of OFDM system that Fig. 1 provides for the embodiment of the present invention;
The structure chart of a kind of embodiment of access device in the WLAN (wireless local area network) that Fig. 2 provides for the embodiment of the present invention;
The structure chart of the another kind of embodiment of access device in the WLAN (wireless local area network) that Fig. 3 provides for the embodiment of the present invention.
Embodiment
Below by drawings and Examples, technical scheme of the present invention is described in further detail.
As shown in Figure 1, it is for achieving the above object a kind of that the embodiment of the present invention provides, first aspect present invention provides a kind of method of reducing PAR of OFDM system, the executive agent of described method can be for access point (the Access Point of subscriber equipment in WLAN (wireless local area network), AP), also can be can accessing WLAN in WLAN (wireless local area network) handheld terminal, described method comprises:
Step 1, the frequency domain symbol signal that needs are sent carries out inverse fast Fourier transform, obtains the first time-domain signal sequence;
Concrete and, corresponding in ofdm system access point or access terminal need the data that send, need to modulate at frequency domain, after modulation, carry out inverse fast Fourier transform (Inverse fast Fourier transform, IFFT), obtain the time-domain signal of modulation signal, owing to adjusting signal, be carried on respectively on different data subcarriers, through N point IFFT, conversion obtains the time-domain signal sequence that N is ordered to the frequency-region signal sequence that N is ordered, and these time-domain signal sequences form an OFDM symbol.
Step 2 is searched over the time-domain signal of power threshold and the time-domain position of described time-domain signal in described the first time-domain signal sequence;
Particularly, after having determined the time-domain signal sequence of modulation signal, select therein the position of several time-domain signals that power is larger and these time-domain signals, also can select power to surpass several time-domain signals of setting thresholding, and determine time-domain position and complex values when power is got maximum;
Concrete, can determine time-domain signal watt level by real part and the imaginary part quadratic sum of complex values in time domain, the real part of time-domain signal and imaginary part can also be contrasted respectively, choose real part absolute value maximum, or the time-domain signal of imaginary part absolute value maximum.
Step 3, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Concrete, can in idle sub-carrier, send independent frequency domain auxiliary signal, or when not needing to carry out channel estimating, pilot tone is reduced to peak-to-average force ratio as frequency domain auxiliary signal, but for these frequency domain auxiliary signals, need to adjust its phase place, make the position of its reverse amplitude maximum after frequency domain to time domain changes identical with the position of the first time-domain signal.
Step 4, is added described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
Concrete, in time domain by the complex values of the time-domain signal of the frequency domain auxiliary signal after adjusting, be added with the complex values of the first time-domain signal, because time-domain position is identical, but single spin-echo, has therefore reduced the amplitude of adjusting signal, because the maximum power value of peak-to-average force ratio and modulation signal is in direct ratio, therefore reached the effect that reduces peak-to-average force ratio
But, only through in prominent time-domain signal in the time-domain signal of the frequency domain auxiliary signal in a subcarrier and frequency-region signal with after peak-to-average force ratio, might not meet the peak-to-average force ratio threshold value of setting, therefore after step 4, system detects the whether satisfied thresholding of setting of described peak-to-average force ratio after reducing, if met the peak-to-average force ratio threshold requirement of setting, stop computing, this auxiliary signal is sent to receiving terminal together with modulation signal, otherwise, in the situation that not meeting setting thresholding, select another one frequency domain auxiliary signal repeated execution of steps 3 to step 4, in the first time domain sequences, select next prominent time-domain signal, adopt frequency domain auxiliary signal on another subcarrier to carry out the operation of peak-to-average force ratio reduction, if after again carrying out, peak-to-average force ratio does not still meet and sets thresholding, can select again to perform step 3 to step 4, until do not meet and set the time-domain signal of thresholding or there is no available frequency domain auxiliary signal.
Pass through the above embodiments, in the poor idle sub-carrier of signal to noise ratio, send reference signal as auxiliary signal or in the situation that not needing channel estimating using pilot signal as auxiliary signal, and adjust the phase place of auxiliary signal, maximum time-domain signal stack in the modulation signal that the reverse maximum of auxiliary signal and needs are sent, in and the method for modulation signal time domain power, reduce the peak-to-average force ratio of adjusting signal in ofdm system, the computation complexity of can demoting, improves signal treatment effeciency.
In a kind of possible execution mode, in the situation that ofdm system is used part bandwidth for transmission data, conventionally only select the good subcarrier carrying of noise ripple to need the data that send, the poor subcarrier of signal to noise ratio becomes idle sub-carrier, therefore, in the present embodiment, transmitting terminal can send auxiliary signal at the poor subcarrier of signal to noise ratio, can reach the effect that reduces PAPR.
For example 802.11ah system is under 2MHz bandwidth, each OFDM symbol of data field has 52 data subcarriers, suppose only to have selected 40 best subcarriers of performance to be used for transmitting data under frequency-selective channel, 12 idle data subcarriers can be used for reducing PAPR, supposes to need with BPSK modulation the data of transmission.
First calculate 40 data subcarriers after IFFT, the time-domain position of prominent 1 point and complex values, and select one group of idle sub-carrier, according to the peaked time-domain position of data subcarrier power, the phase place of symbol in idle sub-carrier is adjusted in the position of the positive and negative and idle sub-carrier of real imaginary part, make idle sub-carrier in the peaked position of data subcarrier power, get symbol maximum on the contrary, then calculate the IFFT of this group idle sub-carrier, after recalculating data stack idle sub-carrier, whether time-domain signal maximum meets the peak-to-average force ratio threshold requirement of setting, if do not meet, increase gradually idle sub-carrier number until satisfied default PAPR thresholding or idle sub-carrier number are used full.
Wherein adjust idle sub-carrier phase place, making the method that its reverse maximum is identical with the position of prominent data field signal can be frequency domain adjustment, namely:
Known idle sub-carrier position K and data time domain maximum position are T, Nc is total sub-carrier number, pi is circumference ratio, exp() represent the exponent arithmetic symbol of natural number e, idle sub-carrier frequency-region signal is multiplied by exp(-j*2pi*K/Nc*T), and be added minimum principle selection sign symbol according to the peaked complex values of data.
Or, in time domain, adjust, first, calculate the IFFT time-domain signal of one group of idle sub-carrier, afterwards, according to order from left to right, according to data time domain maximum position T, the IFFT of this group is carried out to cyclic shift T to the right.According to the peaked complex values of data, be added minimum principle and select sign symbol.
In addition, calculating 40 data subcarriers after IFFT, also can select respectively the larger several data subcarriers of power to be carried out to peak value neutralization by same idle sub-carrier, until peak-to-average force ratio meets setting demand, or not meet the data subcarrier of setting power condition.
In another embodiment, while supposing channel, variable period is longer, therefore channel time changes slower, therefore the pilot tone in data field does not need to carry out channel estimating, therefore the pilot tone for channel estimating can be the same with the idle sub-carrier of above-described embodiment, as the frequency domain auxiliary signal that reduces peak-to-average force ratio, process and previous embodiment are similar, seldom repeat.
Pass through the above embodiments, in the poor idle sub-carrier of signal to noise ratio, send reference signal as auxiliary signal or in the situation that not needing channel estimating using pilot signal as auxiliary signal, and adjust the phase place of auxiliary signal, maximum time-domain signal stack in the modulation signal that the reverse maximum of auxiliary signal and needs are sent, in and the method for modulation signal time domain power, reduce the peak-to-average force ratio of adjusting signal in ofdm system, the computation complexity of can demoting, improves signal treatment effeciency.
Accordingly, as shown in Figure 2, the embodiment of the present invention provides the access device in a kind of WLAN (wireless local area network), and this device can be handheld terminal, can be also the access point (access point, AP) in wlan system, and described device comprises:
Converter unit 201, carries out inverse fast Fourier transform for the frequency domain symbol signal that needs are sent, and obtains the first time-domain signal sequence;
Search unit 202, for described the first time-domain signal sequence, search over the time-domain signal of power threshold and the time-domain position of described time-domain signal;
Processing unit 203, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Arithmetic element 204, in order to described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence are added, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
In an embodiment of the present invention, described frequency domain auxiliary signal is pilot signal or the reference signal for reducing peak-to-average force ratio that sends in idle sub-carrier.
In the possible execution mode of the first, described device also comprises performance element, whether the described peak-to-average force ratio after reducing for detection of described arithmetic element 204 meets is set thresholding, in the situation that not meeting setting thresholding, control described processing unit 203 and described arithmetic element 204 and repeat, until there is no available subcarrier or do not surpass the time-domain signal of power threshold.
By described arithmetic element 204, the second time-domain signal and described first time-domain signal of the frequency domain auxiliary signal after adjusting are added, to reduce the peak-to-average force ratio of described modulation signal, until described peak-to-average force ratio meets, set thresholding or there is no available frequency domain auxiliary signal.
In the foregoing embodiments, 203 pairs of described auxiliary signal adjustment of described processing unit, be specially frequency domain adjustment, described method of adjustment is, frequency-region signal to the subcarrier of described auxiliary signal is multiplied by exp(-j*2pi*K/Nc*T), wherein, K is described sub-carrier positions, and described T is that described the first time-domain signal is in the position of time domain maximum power.
Or the method for adjusting by time domain, according to order from left to right, at the position of time domain maximum power T, is carried out to the right cyclic shift T to the time-domain signal of the auxiliary signal after inverse fast Fourier transform according to described the first time-domain signal.
The embodiment of the present invention provides the access device in a kind of WLAN (wireless local area network), by in the poor idle sub-carrier of signal to noise ratio, send reference signal as auxiliary signal or in the situation that not needing channel estimating using pilot signal as auxiliary signal, and adjust the phase place of auxiliary signal, maximum time-domain signal stack in the modulation signal that the reverse maximum of auxiliary signal and needs are sent, in and the method for modulation signal time domain power, reduce the peak-to-average force ratio of adjusting signal in ofdm system, the computation complexity of can demoting, improves signal treatment effeciency.
As shown in Figure 3, the embodiment of the present invention also provides a kind of access device of WLAN (wireless local area network), described device 30 can be that access point or handheld terminal etc. can be applied in the equipment in WLAN (wireless local area network), and described device 30 can comprise network interface 31, processor 32 and memory 33.System bus 34 is for interconnection network interface 31, processor 32 and memory 33.
Network interface 31 for external device communication.
Memory 33 can be permanent memory, and for example hard disk drive and flash memory, have software module and device driver in memory 33.Software module can be carried out the various functional modules of said method of the present invention; Device driver can be network and interface drive program.
When starting, these component softwares are loaded in memory 33, then by processor 32, are accessed and carry out as given an order:
Step 1, the modulation frequency domain symbol signal that needs are sent carries out inverse fast Fourier transform, obtains the first time-domain signal arrangement set;
Step 2 is searched over the time-domain signal of power threshold and the time-domain position of described time-domain signal in described the first time-domain signal sequence;
Step 3, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Step 4, is added described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
The embodiment of the present invention provides a kind of device of reducing PAR of OFDM system, by in the poor idle sub-carrier of signal to noise ratio, send reference signal as auxiliary signal or in the situation that not needing channel estimating using pilot signal as auxiliary signal, and adjust the phase place of auxiliary signal, maximum time-domain signal stack in the modulation signal that the reverse maximum of auxiliary signal and needs are sent, in and the method for modulation signal time domain power, reduce the peak-to-average force ratio of adjusting signal in ofdm system, the computation complexity of can demoting, improves signal treatment effeciency.
Professional should further recognize, unit and the algorithm steps of each example of describing in conjunction with embodiment disclosed herein, can realize with electronic hardware, computer software or the combination of the two, for the interchangeability of hardware and software is clearly described, composition and the step of each example described according to function in the above description in general manner.These functions are carried out with hardware or software mode actually, depend on application-specific and the design constraint of technical scheme.Professional and technical personnel can specifically should be used for realizing described function with distinct methods to each, but this realization should not thought and exceeds scope of the present invention.
The software module that the method for describing in conjunction with embodiment disclosed herein or the step of algorithm can use hardware, processor to carry out, or the combination of the two is implemented.Software module can be placed in the storage medium of any other form known in random asccess memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.
Above-described embodiment; object of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the foregoing is only the specific embodiment of the present invention; the protection range being not intended to limit the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (16)
1. a method for reducing PAR of OFDM system, is characterized in that, described method comprises:
Step 1, the frequency domain symbol signal that needs are sent carries out inverse fast Fourier transform, obtains the first time-domain signal sequence;
Step 2 is searched over the time-domain signal of power threshold and the time-domain position of described time-domain signal in described the first time-domain signal sequence;
Step 3, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Step 4, is added described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
2. the method for claim 1, is characterized in that, after described step 4, also comprises:
Step 5, whether the described peak-to-average force ratio after detection reduces meets is set thresholding, in the situation that not meeting setting thresholding, uses another frequency domain auxiliary signal, and perform step 3 to step 5, until described peak-to-average force ratio meets, set thresholding or there is no available frequency domain auxiliary signal.
3. the method as described in claim 1-2 any one, is characterized in that, described frequency domain auxiliary signal is pilot signal or the signal for reducing peak-to-average force ratio that sends in idle sub-carrier.
4. the method as described in claim 1-4, it is characterized in that, in described step 3, described frequency domain auxiliary signal is adjusted, comprised frequency domain adjustment, described method of adjustment is, frequency-region signal to the subcarrier of described frequency domain auxiliary signal is multiplied by exp(-j*2pi*K/Nc*T), wherein, K is described sub-carrier positions, and described T is that described the first time-domain signal is at the time-domain position of time domain maximum power.
5. the method as described in claim 1-3, it is characterized in that, in described step 3, described frequency domain auxiliary signal is adjusted, comprise time domain adjustment, described method of adjustment is, according to order from left to right, according to described the first time-domain signal, at time-domain position T, time-domain signal corresponding to described frequency domain auxiliary signal after inverse fast Fourier transform carried out to cyclic shift T to the right.
6. the method as described in claim 1-5 any one, is characterized in that, the described time-domain signal that surpasses power threshold is specially prominent time-domain signal in described the first time-domain signal sequence.
7. the method as described in claim 1-5 any one, is characterized in that, the described time-domain signal that surpasses power threshold is specially the time-domain signal of real part maximum in described the first time-domain signal sequence.
8. the method as described in claim 1-5 any one, is characterized in that, the described time-domain signal that surpasses power threshold is specially the time-domain signal of imaginary part maximum in described the first time-domain signal sequence.
9. the access device in WLAN (wireless local area network), is characterized in that, described access device comprises:
Converter unit, carries out inverse fast Fourier transform for the frequency domain symbol signal that needs are sent, and obtains the first time-domain signal sequence;
Search unit, for described the first time-domain signal sequence, search over the time-domain signal of power threshold and the time-domain position of described time-domain signal;
Processing unit, in the first subcarrier, send frequency domain auxiliary signal, described frequency domain auxiliary signal is adjusted, so that the second time-domain signal after described frequency domain auxiliary signal time-frequency conversion is maximum at the time-domain position power of the first time-domain signal, opposite direction, described the first time-domain signal is prominent time-domain signal in described time-domain signal;
Arithmetic element, in order to described second time-domain signal of the auxiliary signal after adjusting and described the first time-domain signal sequence are added, to reduce the peak-to-average force ratio of described the first time-domain signal sequence.
10. device as claimed in claim 9, it is characterized in that, also comprise performance element, whether the described peak-to-average force ratio detecting after reducing meets setting thresholding, in the situation that not meeting setting thresholding, control described processing unit and described arithmetic element repeats, use another frequency domain auxiliary signal, until described peak-to-average force ratio meets, set thresholding or there is no available frequency domain auxiliary signal.
11. devices as described in claim 9-10 any one, is characterized in that, described frequency domain auxiliary signal is pilot tone or the signal for reducing peak-to-average force ratio that sends in idle sub-carrier.
12. devices as described in claim 9-11, it is characterized in that, described processing unit is adjusted described frequency domain auxiliary signal, comprise frequency domain adjustment, described method of adjustment is that the frequency-region signal of the subcarrier of described auxiliary signal is multiplied by exp(-j*2pi*K/Nc*T), wherein, K is described sub-carrier positions, and described T is that described the first time-domain signal is in the position of time domain maximum power.
13. devices as described in claim 9-11, it is characterized in that, described processing unit is adjusted described frequency domain auxiliary signal, comprise frequency domain adjustment, described method of adjustment is, according to order from left to right, according to described the first time-domain signal, at the position of time domain maximum power T, the time-domain signal of the auxiliary signal after inverse fast Fourier transform is carried out to cyclic shift T to the right.
14. devices as described in claim 9-13 any one, is characterized in that, the described time-domain signal that surpasses power threshold is specially prominent time-domain signal in described the first time-domain signal sequence.
15. devices as described in claim 9-13 any one, is characterized in that, the described time-domain signal that surpasses power threshold comprises the time-domain signal of real part maximum in described the first time-domain signal sequence.
16. devices as described in claim 9-13 any one, is characterized in that, the described time-domain signal that surpasses power threshold comprises the time-domain signal of imaginary part maximum in described the first time-domain signal sequence.
Priority Applications (2)
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| PCT/CN2013/088742 WO2014180128A1 (en) | 2013-05-09 | 2013-12-06 | Method and access device for reducing peak-to-average ratio in orthogonal frequency-division multiplexing system |
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| WO2016177757A1 (en) * | 2015-05-06 | 2016-11-10 | Institut National Des Sciences Appliquees (Insa) | Peak-to-average power ratio reduction in a multi-carrier signal |
| WO2017076125A1 (en) * | 2015-11-05 | 2017-05-11 | Huawei Technologies Co., Ltd. | Systems and methods to reduce the peak-to-average power ratio (papr) of signals in channel bonding |
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| CN108282435A (en) * | 2017-01-06 | 2018-07-13 | 中兴通讯股份有限公司 | A kind of method for transmitting signals and device |
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| WO2014180128A1 (en) | 2014-11-13 |
| CN104144140B (en) | 2017-09-19 |
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