CN101015132A - Pseudo noise coded communication systems - Google Patents
Pseudo noise coded communication systems Download PDFInfo
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- CN101015132A CN101015132A CNA2005800200331A CN200580020033A CN101015132A CN 101015132 A CN101015132 A CN 101015132A CN A2005800200331 A CNA2005800200331 A CN A2005800200331A CN 200580020033 A CN200580020033 A CN 200580020033A CN 101015132 A CN101015132 A CN 101015132A
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Abstract
Systems, apparatus and methods for acquiring code phase and multipath channel models in communication device. A fast Walsh transform engine is used to acquire a pseudo noise code phase and the pseudo noise code bit rate of a radiofrequency signal that has been broadcast. Multipath filter coefficients from the pseudo noise code phase and pseudo noise code bit rate are recovered. A pseudo noise generator is initialized with the pseudo noise code phase acquired during the fast Walsh transform step. The pseudo noise code phase and the pseudo noise code bit rate are tracked by a phase locked loop so that communication with the radiofrequency signal is maintained. Then, the received noise code phase and pseudo noise code bit rate are despread so that any data in the radiofrequency signal is recovered.
Description
Technical field
The present invention relates to pseudo noise coded communication systems, relate in particular to and have the very wireless communication system of the remote transceiver devices of low cost, wherein this transceiver devices can be by a base station transceiver identification so that base station transceiver and remote transceiver can swap datas.
Background technology
Have the application of a lot of communication systems, these communication systems have adopted the base station transceiver that can communicate with many remote transceiver devices.One type system relates to a kind of framework, keeps turn-offing in long-time at this framework medium-long range transceiver devices.In these systems, remote transceiver devices is opened at short notice periodically, makes base station transceiver and remote transceiver devices to communicate, thereby can swap data.In such system, base station transceiver must be discerned the remote transceiver devices of just having opened apace, makes base station transceiver and remote transceiver devices can exchange suitable data.The enforcement of this system must solve many obstacles that cause operational difficulties.
An obstacle is the power consumption of remote transceiver devices.Usually, remote transceiver devices receive electrical power from batteries.When power consumption reduced, the frequency that needs to change battery also reduced.This is important, because remote transceiver devices may be placed on the place that is difficult to arrive, it is unpractical wherein changing battery continually.In addition, even can easily change in those situations of battery at remote-control device, doing so still to be difficult, because these communication systems usually have the part that thousands of even last 100,000 remote transceiver devices are used as network.Change the maintenance costliness that battery also makes a kind of like this system continually, this be do not expect.
Except the problem of power consumption, in the environment of the communication system that comprises thousands of remote transceiver devices often is applied to have radio frequency (" RF ") noise.Although remote transceiver devices must can send the RF noise but base station transceiver can recognition data.And base station transceiver must promptly be discerned remote transceiver, so that make communication system effective.
When a remote transceiver devices attempted to communicate by letter with base station transceiver, this base station transceiver must can be explained the signal that is broadcasted.Therefore, any coding that puts on described data all must with the base station synchronised.Traditional method for synchronous such as all be provided with crystal in remote transceiver devices and base station transceiver, is unpractical.One of them reason is the more of the power ratio expectation used of crystal.Therefore, crystal has significantly reduced battery life.In addition, crystal significantly increases the cost of communication network, because used a system of thousands of remote-control devices to need thousands of crystal equally.So degree ground increase cost is unacceptable.
Attempted allowing the base station to obtain the communication system of the signal of remote transceiver devices.Such as, United States Patent (USP) the 6750814th the relevant wireless signal detection system of a kind of known employing based on FFT described.United States Patent (USP) the 6163548th has been described a kind of pseudo noise code method for synchronous of known employing Fast transforms.United States Patent (USP) the 6717977th has been described the equipment that pseudo noise code and straight sequence code are surveyed in a kind of known being used to.People's such as Srdjan Z.Budisin exercise question is the paper of " FastPN Sequence Correlation by using FWT (being correlated with by using FWT to carry out the PN sequence apace) ", Mediterranean electrotechnics conference proceedings, 1989, the 513-515 page or leaf has wherein been described a kind of fast Walsh transform that uses and has been carried out relevant known method with false noise coding rapidly.The exercise question of Abdulqadir Alaqeeli and Janusz Starzyk is the paper of " Hardware Implementation for Fast Convolution with a PN Code UsingField Programmable Gate Array (adopting field programmable gate array to be used for realizing with the hardware of PN coding fast convolution) ", systemtheoretical southeast conference proceedings, Athens, OH, 2001, a kind of fast walsh transform method that quick detection PN compiles phase place that is used for has wherein been described.The exercise question of Martin Cohn and Abrahan Lempel is the paper of " On Fast M-SequenceTransforms (about quick M sequence transformation) ", IEEE information theory journal, in January, 1977, the 135-137 page or leaf has wherein been described a kind of algorithm that is used for calculating effectively with the multiple correlation of false noise coding.
Ian D.O ｀ Donnell, Mike S.Chen, the exercise question of Stanley B.T.Wang and Robert W.Brodersen is " An Integrated; Low Power; Ultra-Wideband TransceiverArchitecture For Low-Rate; Indoor Wireless Systems (is used for low rate; indoor wireless system a kind of integrated; lower powered, the transceiver framework of ultrabroad band) " paper; IEEE radio communication and networking CAS seminar; 5-6 day in September, 2002 wherein provides example of the pulse communication system of using long pseudo noise (" PN ") yard and a kind of conventional method of PN code phase acquisition.The 7th part of this paper has especially been discussed parallel PN code phase search, and a kind of like this search of narration is " shockingly big ".Therefore, this paper teaches should be carried out the PN code phase acquisition continuously.But continuous PN code phase acquisition cost considerable time, this has negative effect to battery life.
These lists of references all do not have instruction or hint to have immunity to interference and the base station of remote-control device low power consumption or a kind of communication system of remote-control device that is provided for quick remote-control device detection, height.
Summary of the invention
The present invention has described a kind of improved code phase acquisition system and method at this, and it carries out Walsh transformation fast on received radiofrequency signal.Described fast Walsh transform is surveyed the pseudo noise code phase place and the pseudo noise code bit rate of radiofrequency signal.From pseudo noise code phase place and pseudo noise code bit rate, catch the multi-channel filter coefficient.Utilize the pseudo noise code phase place of surveying by fast Walsh transform to come a pseudo noise generator is carried out initialization then.Utilize a phase-locked loop to follow the tracks of pseudo noise code phase place and pseudo noise code bit rate to keep communicating by letter with radiofrequency signal.In case locked, pseudo noise code phase place and pseudo noise code bit rate just by despreading to recover the data in the radiofrequency signal.
Specifically describe above-mentioned and other preferred features now with reference to accompanying drawing, comprise the detailed enforcement of number of different types and the combination of key element, and will point out in the claims.Obviously only the mode by example illustrates concrete method and apparatus, but not as the restriction to it.The principle that those those skilled in the art can understand here and be explained can be applied among different, many embodiment with feature.
Description of drawings
Fig. 1 shows has a kind of typical spread spectrum communication model that puts on modulator pseudo noise (" PN ") expansion before.
Fig. 2 shows has a kind of typical spread spectrum communication model that puts on modulator PN expansion afterwards.
Fig. 3 shows a kind of typical spread spectrum communication model with a plurality of PN code generators that are used to modulate.
Fig. 4 shows a kind of typical functions block diagram of this instruction that is used for the incoherent signal detection.
Fig. 5 shows has the multiple sub-PN position phase sample a kind of typical signal graph of moment.
Fig. 6 shows a kind of typical figure in the three-dimensional search space of probe algorithm of the present invention.
Fig. 7 shows a kind of alternative functional block diagram of this instruction that is used for the incoherent signal detection.
Fig. 8 shows a kind of functional block diagram of this instruction that is used for incoherent signal detection, loop filter locking and data despreading.
Fig. 9 shows by using a kind of incoherent multi-channel filter to be applied to a kind of functional block diagram of this instruction of incoherent signal detection, loop filter locking and data despreading.
Figure 10 shows and uses over-sampling to catch a kind of typical signal graph of sub-PN bit phase samples.
Figure 11 shows a kind of typical functions block diagram of this instruction that is used for the coherent signal detection.
Figure 12 shows by using a kind of relevant RAKE multi-channel filter to be used for a kind of typical functions block diagram of this instruction of coherent signal detection, sign indicating number locking and data despreading.
Figure 13 shows according to an embodiment disclosed herein and describes an a kind of flow chart that is used for the method for incoherent PN code phase acquisition.
Figure 14 shows according to an embodiment disclosed herein and describes an a kind of flow chart that is used for the method for relevant PN encoding phase detection.
Should be noted in the discussion above that these figure draw to scale, and the element of same configuration or identical function is represented with identical reference number generally in order to set forth clearly purpose in all figure.Should also be noted that these figure only are used for helping to set forth the preferred embodiments of the present invention.These figure do not describe each aspect of the present invention, and do not limit the scope of the invention.
Embodiment
Below disclosed every kind of supplementary features and instruction can use individually or combine with other features and instruction, improved communication system and design to be provided and to use the method for this system.Typical example of the present invention has used many supplementary features and instruction individually or in combination, and these examples are described in detail further now with reference to accompanying drawing.This detailed description only is used for saying to the personnel that are familiar with the industry and solves more in detail that putting into practice the preferred aspect of this instruction, and this detailed description does not plan to limit the scope of the invention.Therefore, being combined on the wide significance of disclosed feature and step may not be that to put into practice the present invention necessary in describing in detail hereinafter, but only lectured the exemplary of special this instruction of description.
And many features of exemplary and dependent claims can be not made up by the concrete clear mode of listing, thereby the additional useful embodiment of this instruction is provided.In addition, obviously be noted that, for original disclosed purpose, and the purpose that the theme of being declared is limited for being independent of the combination of features in embodiment and/or the claim, disclosed all features in this detailed description and/or claim and will be separated from each other and disclose independently.And obviously be noted that for original disclosed purpose, and for the purpose that the theme of being declared is limited, the indication of the scope of all values or object group discloses each possible median or medium object.
Fig. 1 shows a kind of spread spectrum communication system block diagram with the modulation of putting on pseudo noise (" PN ") expansion before.(" TP ") can use the structure of Fig. 1 to realize when common spread spectrum technique such as frequency hopping (" HP ") and jumping.Modulator approach is especially compatible mutually with the spread-spectrum structure of Fig. 1 with Orthodoxy Frequency Division Multiplex (" OFDM ") such as pulse position modulation (" PPM ").Shown in the left side of Fig. 1, can be contained in source 100 that transmitter in the remote-control device comprises input data, channel encoder 101, frequency mixer 102, pseudo noise (PN) code generator 103 and a modulator 104.In one embodiment, the input data 100 comprise utilize pseudo noise code (PN coding) and be encoded and utilize any suitable digital modulation technique and modulated pilot signal or beacon signal.Multiplex (MUX) 105 (also i.e. the environment of wherein operational communications system) has carried the information that is sent out, and introduces these that disturb such as multipath reflection, frequency selective attenuation, noise and narrow-band and broadband and worsens phenomenons.Shown in the right of Fig. 1, can be contained in a receiver in the base station and comprise a demodulator 106, one second frequency mixer 107, one the 2nd PN code generator 108, a channel decoder 109 and an output stream 110.
The input data 100 that be sent out in the present embodiment, are encoded as a waveform by channel encoder 101.There are many chnnel codings and decoded form available, such as block code, convolution code, turbine code and low density parity check code.Present embodiment is not limited to select the Code And Decode method.
In one embodiment, modulator 104 and demodulator 106 are linear or approximately linear.Linear modulation is the modulation of deferring to stack, such as, modulation (A+B)=modulation (A)+modulation (B) also is identical for demodulation, such as, demodulation (A+B)=demodulation (A)+demodulation (B).Binary phase shift keying (" BPSK "), quadriphase PSK (" QPSK "), quadrature amplitude modulation (" QAM "), Orthodoxy Frequency Division Multiplex (" OFDM "), amplitude modulation(PAM) (" AM "), frequency modulation(FM) (" FM "), pulse amplitude modulation (" PAM "), on-off keying (" OOK ") and pulse position modulation (" PPM ") all are the examples with the compatible mutually linear modulation method of this instruction.Except should be linear or approximately linear, do not limit about modulation and demodulation scheme this instruction of aspect of the structure of Fig. 1." Digital Communications, 4 referring to calendar year 2001 John G.Proakis
ThEdition (digital communication, the 4th edition) ", McGraw Hill is about the discussion of spread spectrum communication, coding/decoding method and modulation/demodulation methods.
Fig. 2 shows a selection embodiment of spread spectrum system.The direct main distinction of embodiment shown in embodiment shown in Fig. 2 and Fig. 1 is the position of frequency mixer.In the embodiment shown in Fig. 2, frequency mixer 114 is inserted in after the modulator 113.Direct swquence spread spectrum (" DSSS ") modulation is a kind of common technology that can represent by Fig. 2.Can be contained in a transmitter in the remote-control device is illustrated on the left side of Fig. 2.This transmitter comprises an input data source 111, channel encoder 112, modulator 113, a frequency mixer 114 and a PN code generator 115.In one embodiment, the input data 111 comprise utilize pseudo noise code and be encoded and utilize any suitable digital modulation technique and modulated pilot signal or beacon signal.Represent the environment that communication system moves multiplex (MUX) 116 carryings and and worsened signal by sender to receiver broadcasting, wherein this receiver is illustrated on the right of Fig. 2.This receiver comprises one second frequency mixer 117, one the 2nd PN code generator 118, a demodulator 119 and a channel decoder that produces output stream 121.
In an embodiment opposite with embodiment shown in Fig. 1, modulator 113 and demodulator 119 can be non-linear, also can be linear, if not all then also having contained most of modulation schemes, comprising what above mentioned, comprise Continuous phase frequency shift keying (CPFSK) and two kinds of known non-linear modulation schemes of Continuous Phase Modulation (CPM).
Fig. 3 shows the another kind of form of spread spectrum system, and multiple PN extended code sequence has been used in modulation wherein.The example that is applied to the modulator approach of Fig. 3 has cyclic code offset keying (" CCSK "), complementary code keying (" CCK " is used for 802.11), sign indicating number offset keying (" CSK "), Barker code position modulation (" BCPM "), M-ary quadrature keying (MOK), M-ary biorthogonal keying (MBOK) and orthogonal code division multiplexed (" OCDM ").This instruction is not limited to employed modulation format among Fig. 3.
Employed transmitter is illustrated on the left side of Fig. 3 in the embodiment of this communication system.123 pairs of inputs of channel encoder data 122 are encoded.Extended code generator 125 produces the bit stream of multiple PN, quadrature or nearly orthogonal, and this bit stream is provided for a modulator 124 with the data that are encoded.This modulator 124 is selected these signals or these signals are combined with the signal that is encoded, and with the signal that is combined by multiplex (MUX) 126, also be that the running environment of communication system sends.At a receiver shown in the right of Fig. 3 the signal that is broadcasted by multiplex (MUX) 126 is received.
This code generator 125 can produce two M sequences being selected by the data flow that is encoded in the modulator 124, and sends in the multiplex (MUX) 126.In one embodiment, the extended code cycle period symbol rate that equals to be encoded.
By input signal is combined with a synchronous coupling expansion code character from extended code generator 127, and will be input in the receiver demodulator 128 by the signal that multiplex (MUX) 126 sends.In one embodiment, demodulator 128 comprises and one or more input signal is carried out relevant correlator with extended code.
For restoring signal correctly, must be synchronously at the PN or the extended code generator (103 among Fig. 1 and 108,115 among Fig. 2 and 118,125 among Fig. 3 and 127) on channel both sides.In traditional communication system, the crystal in transmitter and receiver will carry out the signal that is sent out and receives synchronously.As previously discussed, crystal is set in transceiver disclosed herein brings shortcoming aspect cost and the power consumption, this just this instruction to overcome.
M sequence and other PN sequences always have narrow (bit) auto-correlation peak value, and this peak value is useful for the demultiplexing in the code division multiple access (" CDMA "), and can have problems when synchronous when the PM code phase that is sent out and receives is carried out.In lower powered of short duration communication plan, wherein radio may enter prolongation and uncertain sometimes powered down sleep period to reduce all batteries consumption, quick detection is even more important.Especially expecting to have a kind of effective ways that are used for quick PN code phase acquisition minimizes power consumption.On mathematics, code phase acquisition is the problem of slide relevant or a convolution.
Fast transform approach has been used to quicken the code phase acquisition problem and has been divided into two classes.Typically calculate the FFT of input sample based on the method for fast Fourier transform (FFT), and do the complex multiplication of a point-to-point with a reference vector, wherein this reference vector is the FFT of the PN code vector of expectation.The result vector that is produced carries out anti-FFT, produces an output vector, and this output vector equals PN sign indicating number and the convolution of input sample in all possible skew.The special PN code phase of input signal produces a peak value in output vector.
Second kind of fast transform approach is based on fast Walsh transform (" FWT "), is also referred to as quick Hadamard transformation (FHT).Walsh transformation and M sequence PN sign indicating number have special relation, and wherein the row of transformation matrix can be by displacement to produce a new matrix, and wherein the row of this new matrix is the order displacement of given PN M sequence.Be applied to code phase search problem, these input data are at first replaced, and carry out FWT then, then by decommutation.Has a peak value on the PN code phase that this output vector will be in the ascendance in the input data.FWT has superiority than FFT, because it only needs to add and subtract, has significantly reduced hsrdware requirements.
In a lot of communication systems, beacon or pilot reference signal are used to make transmitter and receiver synchronous.This beacon permission is provided with the speed of PN sequence at transmitter and receiver place, so making only needs to recover the code phase of transmitter at the receiver place.Other system, those that discuss such as going to, rely on transmitter and receiver place in the same manner the PN sequence rate be set to the stable frequency reference (such as crystal) of an enough accurate value, the so feasible phase place that only needs to recover once more the PN code generator.
In other other system, such as global positioning system (" GPS "), the PN sign indicating number cycle is very long, and frequency may obviously be shifted owing to Doppler effect owing to the high relative velocity between sending and receiving.In this case, need a two-dimensional search to change code phase and code frequency.
For the pulse communication system of using the PN sequence spreading, use such as the quick or accelerating algorithm of FWT or FFT and can't determine PN code phase and frequency.This paper provides many instructions to carry out the quick detection of PN code phase in pulse system.
In an embodiment of this instruction, a kind of method is provided, use a kind of three-dimensional search to recover code phase, frequency and the sub-sample phase of received signals.This method is useful for recovering code phase, frequency and multiplex (MUX) feature, and wherein the multiplex (MUX) feature can be used for multi-channel filter (such as RAKE) coefficient.Additional or selectable, in utilizing the low-power wireless electric system of of short duration or pulse communication, receiver can turn-off on each received bit period period ground, and can not suffer sample to mix repeatedly effect.In one embodiment, transmitter sends the signal of PN M sequential coding, and receiver is determined phase place, frequency and sub-sample phase.
Fig. 4 shows an a kind of exemplary block diagram of incoherent synchronization mechanism, and wherein this mechanism is used for code frequency, code phase and the sub-PN bit phase of the signal of a definite M sequence PN sign indicating number.The circuit of this structure is realized being present in the remote transceiver usually.Input data 135 are transported in envelope detector/amplifier 137.In one embodiment, input data 135 comprise pilot tone or the beacon signal of utilizing pulse modulation technique modulation PN sign indicating number coding and that utilize any appropriate.Additional or selectable, one or more frequency mixer (not shown), one or more filter (not shown) and/or one or more booster amplifier (not shown) can be used for before envelope detected or as the part of envelope detected input signal being converted to its base band state.The output of envelope detector/amplifier 137 is envelope signals.Be noted that and also can use for known other Front end radio receiver structures of industry those of ordinary skill.
Analog to digital converter (" ADC ") 138 receives this envelope signal and carries out digitlization.In another embodiment, before envelope detected, carry out digitlization, thereby allow envelope detected to realize with digital circuit.Fig. 5 shows the sample of a digitlization M sequential coding signal 11 of being seen in the output of ADC 138.Select among the embodiment at one, the output of ADC 138 can be a pulse signal 14, and this also is illustrated in Fig. 5.ADC 138 samples to the output of envelope detector with speed and phase place, and wherein this speed and phase place are by determining in the programmable oscillator 139 such as voltage controlled oscillator shown in Fig. 4.Be noted that many instructions here allow to use oscillator very low cost, low precision and do not need crystal.2
NA vector of-1 sequential sampling is collected, and wherein the length of M sequence is 2
N-1.This sample vector is resequenced according to a displacement mapping.The sample vector of being replaced is imported into a FWT engine 141, and this engine is carried out fast Walsh transform.The output of FWT engine 141 is imported in the peak detector 142, and this peak detector can be determined the maximum output that FWT engine 141 is produced.Decommutation function 143 can be mapped as peak a code phase.
Fig. 6 shows a typical three-dimensional search space of probe algorithm of the present invention.As shown in Figure 6, all sampling rates 15 of the time range paid close attention to containing of oscillator 139 (such as seeing Fig. 4) and sub-sample phase 16 is combined into line scanning.The scope of being paid close attention to is exactly the hunting zone, and depend on the degree of local oscillator (also this device for park mode time) drift when this device does not send, it is much to depend on that perhaps local oscillator has stood such as other factor affecting of component ageing, ambient temperature, cell voltage etc.In Fig. 5, show corresponding to one group of many sub-sample phase possible sampled point 13.Every group of sampling time 12 all is used at each FWT 18 shown in Fig. 6.On each sampling rate and sub-sample phase, 2
N-1 sample is added up, and handles by FWT engine 141.For each sampling rate and sub-sample phase, peak detector 142 has been determined the data set (2 that is being sampled
N-1 point) with the maximal correlation of target P N M sequence.Have that to be determined from the oscillator sampling rate of the peak-peak of peak detector 142 and sub-sample phase be the code phase that mates most, frequency (also being sampling rate) and sub-sample phase.
In another embodiment, oscillator 139 only scans the last known sampling rate and the speed and the phase place working point of sub-sample phase and direct neighbor.This searching algorithm can obtain optimal results along the relevant gradient of peak value.Local search method and other optimisation techniques are that the industry is in common knowledge, and its selection is not construed as limiting this instruction.
In one embodiment, the receiver AFE (analog front end) only is activated time of a weak point to save energy during each PN bit period.Such as, receive envelope detector/amplifier 137 10ns that may during the PN of 100ns bit period, only be activated.The sampling of this short duration may cause a routine search in code phase and sampling rate to miss signal peak.In this embodiment, need sub-sample phase search to come successfully detectable signal.
In another embodiment, input signal uses amplitude modulation(PAM) (AM), pulse amplitude modulation (PAM), on-off keying (OOK) modulation and modulated.
Fig. 7 shows a kind of selection of a kind of incoherent receiver that is used for the signal code phase detection and implements, and this receiver was discussed hereinbefore, and this receiver will typically be arranged in the remote transceiver.Input signal 150 comprises the pulse guide-frequency or the beacon signal of the pulse amplitude modulated signal that is encoded such as utilizing the PN sign indicating number, this input signal 150 is imported in the quadrature mixer/filter/amplifier 152, and wherein this quadrature mixer/filter/amplifier 152 comprises that at least one frequency mixer, one or more optional amplifier and one or more optional filter are to be transformed to input signal 150 a quadrature base band or intermediate frequency state.This analog front end down conversion procedures is that the industry is in common knowledge, and this instruction does not limit the implementation detail of quadrature frequency reducing front end.A quadrature oscillator 153 produces two reference signals to be used for the relative phase of one 90 degree of down conversion.This quadrature mixer/filter/amplifier 152 produces two quadratures outputs, I and Q, this output by ADC 155 and 156 to be digitized by oscillator 154 determined sampling rates and phase place.The signal that is digitized is combined in magnitude calculator 157.In one embodiment, this magnitude calculator is calculated the square root (" RMS ") of I and Q input, also is output=sqrt (I
2+ Q
2).In an alternative of magnitude calculator, can also be output=abs (I)+abs (Q) to the absolute value summation of I and Q.This instruction does not limit the selection of magnitude calculator 157.This quadrature down conversion front-end structure always makes a farfetched comparison the envelope detector front end shown in Fig. 4 more preferably, because carrier frequency is adjustable in a wide scope, out-of-band signal/noise is easier to be suppressed and always can to use more cheap parts.
The output of magnitude calculation 157 is collected as 2 as in the previous
NOne 2 of the M sequence of-1 length
NThe vector of-1 sample.This vector is imported into a permute reorder 158 then, follows a FWT 159 afterwards.The output of FWT 159 is one and has 2
NThe vector of-1 point equals the convolution that the quilt of target M sequence is replaced, and is transfused to a peak detector 160.The index output of peak detector 160, the index that also is peak value is by the found code phase of a decommutation function 161 with indication input signal M sequence.This code phase can be used to make PN generator (such as 103, the 115 or 125) synchronised of PN generator (such as 108,118 or 127) Yu the transmitter of receiver subsequently according to the requirement of spread spectrum communication.
Fig. 8 shows an a kind of exemplary block diagram of selectable non-coherent code detection system, and wherein this system comprises frequency lock mechanism and data despreader, and wherein this data despreader can be implemented in remote transceiver.Input signal 250 is imported in the quadrature mixer/filter/amplifier 252, wherein this input signal 250 comprises pilot tone or the beacon signal of utilizing the PN sign indicating number and being encoded, and this quadrature mixer/filter/amplifier 252 comprises that at least one frequency mixer, one or more optional amplifier and one or more optional filter are to be transformed to input signal 150 a quadrature base band or intermediate frequency state.This analog front end down conversion procedures is that the industry is in common knowledge, and this instruction does not limit the implementation detail of quadrature down conversion front end.A local quadrature oscillator 253 provides two reference signals that are nominally 90 degree out-phase to this quadrature mixer/filter/amplifier 252.The output of this mixer/amplifier 252 is digitized by ADC 255 and 256, be imported into then with above-mentioned 157 functionally similar magnitude calculator 257 in.ADC 255 and 256 drives by a programmable oscillator 254, and this programmable oscillator 254 is used for stepping and controls foregoing various search rate and phase place.The output of magnitude calculator 257 at first is imported in the permute reorder 258, and this sorting unit 258 carries out 2
NSample and, be correlated with for-1 time with the M sequence of preparing to carry out based on FWT to their ordering.Sample to displacement is carried out FWT259, and its output is transfused to a peak detector 260.The output of this peak detector is imported in the decommutation function 261, and this function provides the PN code phase 262 of the peak value that is detected.
PN code phase 262 can be used for PN generator 263 of initialization, producing the local form of a PN sign indicating number that is received, and itself and the signal that is detected homophase roughly.In one embodiment, oscillator 254 is programmed to the frequency and the phase place setting of detected peak value, 2
N-1 new samples is collected and is sorted, and FWT is calculated, and peak detector 260 is the same as described above with decommutation function 261 to be used to produce a current PN code phase, and this PN code phase is used to initialization PN generator 263.In the time producing slight variation may for oscillator frequency and/or phase place, this peak value re-detection may be repeated several times.The purpose of this step is the best current assessment that a current PN code phase is provided to PN correlator 264 and 267.Local PN generator 263 produces the PN sign indicating number identical with input signal, roughly homophase.In one embodiment, PN generator 263 provides clock pulse by oscillator 254.By the 263 PN sign indicating numbers that produced be imported into one the morning/late correlator block 264, this piece 264 comprises at least two correlators as phase correlator, this correlator block provides a signal, this signal is at first filtered in loop filter 265, be fed to then oscillator 254 with according to this morning/late signal regulates its frequency.Oscillator 254, ADC 255 and 256, magnitude calculator 257, early/late correlator 264, PN generator 263 and loop filter 265 constitute phase-locked loops (" PLL "), input PN sign indicating number bit frequency and phase place are followed the tracks of in this phase-locked loop.Allow this loop to start to the initialization of PN generator 263 or, make that morning/late correlator 264 is in the scope that correct signal is provided by initial p N code phase near correct frequency and phase place.Frequency during the FWT search procedure and phase step must be enough meticulous, so that allow to realize the parts locking initial value of PLL.
In another embodiment, utilize one the 2nd PN sign indicating number and one second data-signal being encoded can from transmitter be sent out and with a PN sign indicating number overlaid that is used for PLL.One the 2nd PN generator 266 can produce the sign indicating number identical with this PN numeric data code, and wherein to allow one or more correlators 267 with a PN code phase synchronised time be the data flow 268 of a despreading with the output transform of this magnitude calculator 257 to this PN numeric data code.In another embodiment, a PN sign indicating number that is used for locking mechanism is a M sequence code.In another embodiment, these second data PN sign indicating number is and the equal in length of a PN sign indicating number that is used to lock or short M sequence code.In an alternative, the length that is used for the 2nd PN sign indicating number of growth data is the multiple that is used for the PN code length of PLL, and these data PN generator 266 must cycle through a plurality of start-phase, up to the output maximum of this correlator 267.
Perhaps, the 2nd PN sign indicating number is not the multiple of a PN sign indicating number, and uses a kind of alternative method of data synchronization.Such as, length is 2
NThe repetition beacon sequence of a PN sign indicating number of-1 can be replaced by sometimes one with the expression frame period boundary line length alternative PN sequence identical or inequality.One second correlator (not shown) is monitored by the beacon signal of demodulation to determine existing of the 2nd PN sequence.If the 2nd PN sequence is detected, this transceiver restarts a frame counter (not shown) so, and wherein this counter receives whenever that then a PN sequence just adds one.The data of carrying the 2nd PN sign indicating number therein are longer than under the situation of a PN beacon-code, can regularly establish this second code phase clearly in the border with respect to frame.Like this, sequential is longer than the idea of a PN sequence and can be carried out between base station and remote transceiver synchronously, and the 2nd long PN sign indicating number easy to use carries out transfer of data.Can understand that for the people who is familiar with the industry many similar frame synchornization methods can be replaced, and not break away from the category of this instruction.
Fig. 9 shows and is used for a kind of alternative incoherent block diagram that the PN sign indicating number locking of use PLL and multi-channel filter was surveyed, passed through to the PN coding.In one embodiment, the operation of system shown in Fig. 9 is included in four key steps shown in Figure 13.First step is to survey PN code phase and PN sign indicating number bit rate 290, also promptly determines an approximate correct sampling rate.Second step is to catch multi-channel filter coefficient 292 from the FWT data.Third step is an initialization PN generator 294.The 4th step is locking and the received data 196 of despreading of PLL.In case finish these steps, code phase is just locked with regard to the signal that has been detected and has been broadcasted so, makes that so base station transceiver and remote transceiver can swap datas.
The detection 290 of PN code phase and PN sign indicating number bit rate is in fact realizing with the described identical mode of preamble, and the input data 170 that also promptly have a beacon signal are at first detected and be transformed to a baseband signal by envelope detector/amplifier 172 or its equivalent device.In an alternative, this envelope detector/amplifier 172 and a described mixer/amplifier and the down conversion local oscillator (not shown) of being replaced by similarly of preamble.This signal is digitized with speed and the sub-PN bit phase that programmable oscillator 174 sets by ACD 173 then.This oscillator is programmed to a series of search points in the sub-PN bit phase/sample-rate space shown in Fig. 6 then, all carries out 2 on each space
NSample for-1 time, and be arranged with replacing by 175.Carrying out 176, one peak detectors 177 of FWT on the data vector of each displacement is used for classification as a result.At the end of search phase (step 290), best sample frequency and sub-sample phase are obtained.
In an embodiment shown in the sample graph of Fig. 5, for each sub-PN bit phase 13 has been carried out repeatedly sampling.A plurality of PN bit phase vectors can be assembled, and such as 12 among Fig. 5, one of the sub-PN bit phase that each is studied is imported in the FWT engine 176 then.Such as, ADC 173 can be in the PN bit period of 100 nanoseconds with cycle (10 of a nanosecond
9Inferior samples/sec) samples (100x over-sampling).Similarly, can all make up one group 2 in 100 sub-PN bit phase each
NThe sample vector of-1 length.Using FWT engine 176 and 177 pairs of all 100 sample vectors of peak detector to carry out peak value determines.In case the global peak of all 100 FWT operations is determined, can recover near the residual F WT output this peak value so, to create a time-domain model of multiplex (MUX) 105,116,126.This multichannel model snapshot (snapshot) can be used for multi-channel filter 181 is programmed.
In order to catch the multi-channel filter coefficient from the FWT data, step 292 is used to obtain the FWT result of frequency, and the two-dimensional result block 19 such as Fig. 6 is programmed in the multichannel matched filter 181 as tap weight.The sub-PN bit phase output of FWT is directly proportional with multipath reflection in the input signal of source PN code signal.In one embodiment, FWT results of all search points are stored in the memory (not shown), in case and peak sample rate be known, then multichannel matched filter 181 taps (Fig. 9) are taken out in programming from this memory.Before in being programmed into this multichannel matched filter 181, this FWT result is by decommutation 180.In an alternative, in case peak sample rate is known that then programmable oscillator 174 is set to this optimum frequency, and tests a plurality of phase places, to produce FWT result again and to catch multichannel matched filter 181 coefficients.In an alternative, this multi-channel filter coefficient is set to a nonce, further improvement after PLL locking and despreading are received data then, and PLL once just locks onto input signal.
For initialization PN generator 294, be used to come initialization PN generator 182 from the PN code phase data 179 of FWT/ decommutation function (such as seeing Fig. 9, piece 178).In one embodiment, after the best ADC sampling rate of search, programmable oscillator 174 is set to this best sampling rate.An additional permute/FWT/ decommutation is performed to find current PN code phase 179, and this code phase is used to initialization PN generator 182.
Have the data that are encoded in the input signal 170.Typically, input data 170 have a plurality of message of using long PN sign indicating number simultaneously and being encoded, and this long PN sign indicating number is added on this signal.In order to make PLL locking and the received data of despreading, step 296, correlator 183 provides a correction signal to tracking filter 159, and these tracking filter 159 driving oscillators 174 are to constitute a PLL.This PLL comprises oscillator 174, ADC 173, multi-channel filter 181, correlator 183 and tracking filter 159.In addition, this correlator 183 also extracts despread data 184, may also utilize among one or more and this PLL employed different PN sign indicating number to encode.In addition,, can carry out a series of FWT or relevant, to be provided with, to improve or to follow the tracks of multichannel matched filter 181 coefficients in case PLL is locked.
Can carry out each in the step 290 relevant, 292,294 and 296 independently, perhaps to carry out with aforementioned different order with Fig. 9.This instruction is not limited to the order, combination of these listed steps or it is replaced with other steps known or that described.
Figure 10 shows a base-band input signal waveform 21 with PN sign indicating number cycle 20 and binary value.In an alternative, the output of ADC 173 can be a pulse signal 24, and this also is illustrated in Figure 10.In one embodiment, ADC 138,155,156,256 and/or 257 is clocked to one than the high speed of input PN coding bit rate, equalisation of over-sampled signals is obtained all sub-PN bit phase samples, shown in sampled point among Fig. 9 23.Displacement/sort block (140,158,175,258) is got every k sample 22 then, constitutes an input vector that is sorted, and is used for FWT piece (141,159,176,259), and wherein the k scope is from 0 to P～1, and P is the number of sub-PN bit phase.Such as a, input signal with PN bit period of 100 nanoseconds can use a 1GHz the ADC piece and by over-sampling 100x.100 sub-PN bit phase are arranged in this example, and each all produces 2
NA vector of-1 sample carries out FWT to be handled, and 100 FWT of its needs operate and handle.The multichannel resolution that is produced will be a nanosecond.
Figure 11 shows a kind of coherent signal phase acquisition block diagram.Input signal 185 the is imported in the quadrature mixer/filter/amplifier 187 as previously mentioned, and this quadrature mixer/filter/amplifier 187 produces I and Q baseband signals.These signals are digitized by ADC190 and 191.This quadrature mixer/filter/amplifier 187 drives by a local quadrature oscillator 188, wherein this quadrature oscillator 188 reference signal that two 90 degree out-phase are provided to this frequency mixer with to the input signal down conversion.This ADC is used to use a clock that obtains such as a division circuit 189 and be driven from quadrature oscillator frequency.In one embodiment, the phase relation between ADC 190 191 clocks and quadrature oscillator 188 must be relatively-stationary and stable, to allow coherent detection.
The output of each ADC (ADC 190 and ADC191) preferably keeps separating, and so makes signal-to-noise characteristic increase.The composition of each quadrature is all by the displacement rearrangement.See piece 192 and 193.Then, the orthogonal component that reorders of each displacement all is imported into FWT 194,195 and handles.FWT 194 is combined at piece 196 places to find out the relevant value of plural number with 195 output.By carry out magnitude/peak detection after despreading, signal to noise ratio increases.FWT result's peak value has been determined in this peak value detection 196, and this peak value is remapped by decommutation function 197 then, to produce output PN code phase 198.When comparing with incoherent detection, the advantage of coherent detection comprises ability preferably and the high processing gain that suppresses noise.But, normally to carry out in order to make coherent detection, quadrature oscillator 188 and the ADC sampling rate that is produced by piece 189 must have a fixed phase relation.Known in the prior art have many methods to fix two phase relations between the oscillator, comprises frequency division, phase-locked loop (PLL) and delay-locked loop (" DLL ").This instruction is not limited to remain on the method for stationary phase between ADC sampling rate and the quadrature oscillator 188.Be noted that the system that realizes coherent detection since need between fixed oscillator 188 and the ADC 190,191 phase relation and will be more expensive than those systems that realize incoherent detection.
Figure 12 shows based on a kind of relevant PN code phase acquisition of the relevant PN sign indicating number detection system of Figure 11, plural multi-channel filter and data despreading system block diagram.In one embodiment, the system of Figure 12 carries out following method, and this method is illustrated in Figure 14.Should relevant PN code phase acquisition method survey PN code phase and PN sign indicating number bit rate 300.In second step, utilize the complex conjugate of FWT data this plural number multi-channel filter coefficient 310 of programming.In third step, this PN generator is initialised 320.The 4th step is locking and the received data 330 of despreading of PLL.In case finish these steps, code phase just is detected so, and the signal that is broadcasted is just locked, makes that so base station transceiver and remote transceiver can swap datas.
So in these steps or some, input signal 200 is imported in the quadrature mixer/filter/amplifier 202 as described above similarly.This quadrature mixer/filter/amplifier 202 drives by a quadrature oscillator 203 able to programme, and this quadrature oscillator 203 provides two reference signals that are nominally 90 degree out-phase to be used for down-conversion process, and this is that prior art is in common knowledge.By the orthogonal signalling of down conversion, I and Q are imported in two ADC204 and 205, and wherein these two ADC carry out digitlization with a sampling rate that sets by piece 206 to I and Q signal.Piece 206 provides a sampling clock that has fixed phase relationship with quadrature oscillator 203.In one embodiment, piece 206 produces a clock than low velocity with the quadrature oscillator clock divided by a fixing number.Be used to realize that other phase places, frequency or the delay-locked loop of identical functions are that prior art is in common knowledge, and can replace 206 or 203.
In the first step of relevant PN code phase acquisition method, survey PN code phase and PN sign indicating number bit rate 300, this quadrature oscillator and I and Q sampled signal are combined into length 2
N-1 vector (identical with the length of input PN M sequence) is resequenced by permutation function 207 and 208, is input to two FWT pieces 209 and 210 then, each one of I and Q.FWT piece 209 and 210 output are imported in the magnitude peak detector 210, wherein this magnitude peak detector 210 the RMS that calculates FWT I and Q vector on the pointwise basis or other functions that is similar to value (also promptly in value vector as a result 2
N-1 point).This magnitude peak detector 211 finds and notes down the sampling rate and the peak phase of maximum magnitude point then.When in step 300, surveying PN code phase and PN sign indicating number bit rate, ADC 204 and 205 programmable sample rate and the inswept a series of checking operating point of frequency of phase place and quadrature oscillator 203.In one embodiment, this quadrature oscillator 203 and divider 206 change independently of each other.In another embodiment, change the divisor ratio M in the piece 206, between quadrature oscillator and ADC sampling rate, keep a definite phase relation with requirement according to coherent detection.By replacing with PLL or DLL with 206, PLL or DLL also can be used for the search of independently similar or phase locking.
Peak value value throughput value peak value on the hunting zone detects piece 211 to be determined, wherein this magnitude peak detects piece 211 index is sent to a decommutation function 214 to recover PN code phase 219.This PN code phase 219 is used for the one or more PN generators 221 of initialization, and this PN generator 221 is used to be provided with the PLL lock function when initialization PN generator (step 320) after a while and data are recovered.
At searching period, the output of FWT piece (209 and 210) is hunted down in two random access memory (" RAM ") 212 and 213.In case peak value is known, use the peak sample rate of a selector 215 so to determine, from RAM 212 and 213, read one section 3D FWT Search Results 19.This selector returns near I and the QFWT result peak value PN code phase, comprises PN code phase and sub-PN bit phase, with multipath effect in multipath effect between cover symbol and the symbol.Such as, if the designer need carry out the multichannel filtering of 300 nanoseconds with the PN sign indicating number bit period of one 100 nanosecond and 1GHz ADC sampling rate, this selector will return 300 points (100 sub-PN bit points multiply by three PN code phases) so, this selector provides the correlated results (plural number) of 300 nanoseconds, wherein each one nanosecond of step-length.FWT result 19 2D fragment is serialized near this peak F WT value, to recover a 1D multichannel model longer arbitrarily than single PN bit period.The every bit of the 1D multichannel model that is resumed provides a high-resolution sub-PN bit multichannel model all corresponding to a sub-PN bit phase step relative offset.The output of selector 215 is plural multichannel models with channel of sub-PN bit phase resolution.
The Q composition of this multichannel model,, is loaded to a plural number coupling multi-channel filter 220 to form selecteed FWT result's complex conjugate by anti-phase then by phase inverter 218.To carry out plural number relevant with input signal data from ADC 204 and 205 then for plural number multi-channel filter 220.In an alternative, this plural number multi-channel filter is a plural RAKE filter.Near the complex conjugate of the M maximum magnitude during in another embodiment, this RAKE tap coefficient is set to passing through peak detector 211 determined FTW peak values.
In third step 320, the PN code phase of being surveyed in first step 219 is used to the code phase of the one or more PN generators 221 of initialization, and this PN generator offers two or more correlators 222 and 223 with their one or more PN sign indicating numbers that produce in turn.This plural number multi-channel filter 220 provides a plural I and Q filtering signal, and this filtering signal carries out relevant in correlator 222 and 223, is imported into one or more signals in the tracking filter 225 with generation.In one embodiment, this correlator 222 is relevant morning/evening with 223 execution, and one or more acceleration signals are transferred to tracking filter 225.
In one embodiment, this tracking filter 225 provides a coherent signal to quadrature oscillator 203, and by the fixed relationship between quadrature oscillator 203 and the ADC sampling clock divider/DLL/PLL 206 the ADC sampling rate is proofreaied and correct.In another embodiment, this quadrature oscillator 203 is the independently oscillators of free-running operation.
This correlator 222 and 223 also can carry out input multichannel filtering data flow and other PN sign indicating numbers on overlapping onto input signal 200 relevant, with encoded data stream.This optional data PN sign indicating number can be identical or different with the length of described phase acquisition code.In one embodiment, the PN code length of detection is longer than the PN code length that is used for transfer of data, preventing the ambiguousness in these data PN code phase, and is used for reducing the size of the error that the noise owing to filter coefficient causes.In another embodiment, the length of being surveyed with data PN sign indicating number is at double, to be reduced in the complexity of phase coordination between FWT and the correlator.
It (promptly is not 2 that the code length of PN sign indicating number that is detected and data PN sign indicating number may be expanded a bit yet
N-1 but 2
N), to keep a simple length multiple relation.Such as, a PN acquisition code may be 2048 bit long, a data PN sign indicating number may be 512 bit long, and the relation of factor 4 is arranged.Perhaps, if should survey the PN sign indicating number than data PN code length, the data PN sign indicating number of one group of order can replenish additional bit so, with the equal in length that is detected the PN sign indicating number.This correlator 222 and 223 and PN generator 221 can suitably shift to an earlier date or delayed data PN sign indicating number, suitably to keep the data extract phase place.Such as, if this detection PN code length is 2047 (=2
11-1), and data PN code length be 511 (2
9-1), the data PN code length that can utilize 3 quilts to replenish an additional bit so makes up four numeric data codes with the length with this detection PN sign indicating number be complementary (such as 512+512+512+511=2047).
Those personnel that are familiar with the industry will recognize that a plurality of embodiment disclosed herein can easily realize multiple variation and alterative version, and specific examples wherein illustrates and describes in detail at this by the mode of example in the accompanying drawing.
Claims (13)
1. be used for a kind of device of acquisition code phase place, comprise:
An oscillator;
The analog to digital converter of a receiving baseband signal, described analog to digital converter is to be come described baseband signal is sampled by the speed of described oscillator control;
A fast Walsh transform engine, this fast Walsh transform engine receive the displacement output of described analog to digital converter and export an output vector; With
A peak detector, this peak detector is detection peak in described output vector.
2. the device of claim 1, wherein said baseband signal produces by an envelope detector.
3. the device of claim 1, wherein said peak detector comprises a plurality of correlators.
4. the device of claim 1, wherein the described output vector from described peak detector is applied thereon a decommutation function, so makes a peak can be mapped as a code phase.
5. the device of claim 1, the output of wherein said analog to digital converter comprises one 2
NThe vector of-1 order sample has 2 thereby produce one
NThe M sequence of-1 sample length.
6. the device of claim 5, wherein said output vector has described peak value on a main pseudo noise code phase place of described M sequence.
7. the device of claim 1, wherein said oscillator is a programmable oscillator.
8. the device of claim 1, wherein said oscillator is a transformable oscillator.
9. method that is used to survey from the radio frequency signals of long haul radio frequency transceiver, wherein said long haul radio frequency transceiver is broadcasted a signal with pseudo noise code phase place and pseudo noise code bit rate, and this method comprises:
Carry out a fast Walsh transform on described radio frequency signals, wherein this radio frequency signals has been digitized pseudo noise code phase place and the pseudo noise code bit rate to survey this radio frequency signals;
From the result of described fast Walsh transform, determine the multi-channel filter coefficient; And
During described fast Walsh transform step, utilize the pseudo noise code phase place that is obtained to come pseudo noise generator of initialization;
Follow the tracks of described pseudo noise code phase place and pseudo noise code bit rate to keep communicating by letter with described radio frequency signals.
10. method that is used to survey the sub-PN bit phase of a M sequence PN coded pulse signal comprises:
Produce the vector of a sequential sampling the M sequence PN coded pulse signal of and displacement digitized from one;
Described vector is carried out a fast Walsh transform;
Detect the peak value output of described fast Walsh transform; And
Described peak value output is mapped as a code phase, and described peak value output is corresponding to a beacon signal, and indication is with the signal that is detected.
11. a method that is used for the direct impulse radio frequency signals, this impulse radio frequency signal have sampling rate and sub-sample phase and utilize a predetermined sign indicating number sequence and be encoded, this method comprises:
All sampling rates and the sub-sample phase that covers the time range of being paid close attention to scanned;
On each sampling rate and sub-sample phase, sample is added up;
Described sample is carried out a fast Walsh transform; And
At each sampling rate and sub-sample phase, in described sample, determine the correlation with described predetermined codes sequence, maximal correlation is corresponding to the phase place of the described predetermined codes sequence that will be detected.
12. the method for claim 11, wherein said predetermined codes sequence are pseudo noise codes.
13. a method that is used to survey from the beacon signal of long haul radio frequency transceiver broadcasting, wherein said beacon signal has a pseudo noise code phase place, and this method comprises:
An impulse radio frequency signal that has been digitized is carried out a fast Walsh transform, thereby produce an output vector;
In described output vector, detect a peak value;
To described peak value decommutation to find the pseudo noise code phase place;
Follow the tracks of described pseudo noise code phase place to keep communicating by letter with described beacon signal; And
Described noise code phase place of despreading and pseudo noise code bit rate are to recover any data in described radio frequency signals.
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| US60/582,888 | 2004-06-25 | ||
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| CNA2005800200331A Pending CN101015132A (en) | 2004-06-17 | 2005-06-16 | Pseudo noise coded communication systems |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102415001A (en) * | 2009-04-29 | 2012-04-11 | Lg电子株式会社 | Method for generating reference signal sequence in multi-antenna wireless communication system and apparatus for same |
| CN105429651A (en) * | 2015-10-29 | 2016-03-23 | 北京中科汉天下电子技术有限公司 | FM pilot signal generation method and circuit |
| CN112448729A (en) * | 2019-08-30 | 2021-03-05 | 瑞士优北罗股份有限公司 | Discrete time superheterodyne mixer |
| CN112737984A (en) * | 2020-12-25 | 2021-04-30 | 中国科学院声学研究所 | Frequency response estimation and signal transmission method and system for multi-carrier incoherent underwater acoustic communication |
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| US9571265B2 (en) * | 2015-07-10 | 2017-02-14 | Tempo Semicondutor, Inc. | Sample rate converter with sample and hold |
| CN112200038B (en) * | 2020-09-29 | 2023-12-05 | 国网四川省电力公司经济技术研究院 | CNN-based quick identification method for oscillation type of power system |
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2005
- 2005-06-16 CN CNA2005800199989A patent/CN1981453A/en active Pending
- 2005-06-16 CN CNA2005800200331A patent/CN101015132A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102415001A (en) * | 2009-04-29 | 2012-04-11 | Lg电子株式会社 | Method for generating reference signal sequence in multi-antenna wireless communication system and apparatus for same |
| CN102415001B (en) * | 2009-04-29 | 2014-04-02 | Lg电子株式会社 | Method for generating reference signal sequence in multi-antenna wireless communication system and apparatus for same |
| US9160429B2 (en) | 2009-04-29 | 2015-10-13 | Lg Electronics Inc. | Method for generating reference signal sequence in multi-antenna wireless communication system and apparatus for same |
| US10038536B2 (en) | 2009-04-29 | 2018-07-31 | Lg Electronics Inc. | Method for generating reference signal sequence in multi-antenna wireless communication system and apparatus for same |
| CN105429651A (en) * | 2015-10-29 | 2016-03-23 | 北京中科汉天下电子技术有限公司 | FM pilot signal generation method and circuit |
| CN105429651B (en) * | 2015-10-29 | 2018-02-13 | 北京中科汉天下电子技术有限公司 | A kind of FM pilot signals generation method and circuit |
| CN112448729A (en) * | 2019-08-30 | 2021-03-05 | 瑞士优北罗股份有限公司 | Discrete time superheterodyne mixer |
| CN112737984A (en) * | 2020-12-25 | 2021-04-30 | 中国科学院声学研究所 | Frequency response estimation and signal transmission method and system for multi-carrier incoherent underwater acoustic communication |
| CN112737984B (en) * | 2020-12-25 | 2022-04-29 | 中国科学院声学研究所 | Frequency response estimation and signal transmission method and system for multi-carrier incoherent underwater acoustic communication |
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