CN1161765A - Method and apparatus for fast fourier transform based maximal ratio combining - Google Patents
Method and apparatus for fast fourier transform based maximal ratio combining Download PDFInfo
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- CN1161765A CN1161765A CN 95195854 CN95195854A CN1161765A CN 1161765 A CN1161765 A CN 1161765A CN 95195854 CN95195854 CN 95195854 CN 95195854 A CN95195854 A CN 95195854A CN 1161765 A CN1161765 A CN 1161765A
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Abstract
A method and apparatus diversity-combined radio signals received from a plurality of branches (108,214). Each radio signal comprises a plurality of subchannels (806). The radio signal from each branch (108,214) is digitized (904) into digital samples that are converted (908,910) into frequency domain signals (702,712). Each frequency domain signal (702,712) corresponds to a subchannel and a branch (108,214). A weighting factor is determined for each branch (108,214) and each subchannel (806) from instantaneous signal energy and noise power calculated (912,914) from the frequency domain signals (702,712). The frequency domain signal (702,712) corresponding to each branch (108,214) and each subchannel (806) is multiplied (918) by the weighting factor therefor to produce weighted frequency domain signals corresponding to each branch and each subchannel. The weighted frequency domain signals that correspond to all the branches (108,214) of each subchannel (806) are then combined (920) to produce a diversity-combined frequency domain signal for each subchannel (806).
Description
The present invention relates to general wireless communication receiver, relate in particular in the wireless communication receiver system, a kind of rapid fourier change method and apparatus that merges based on high specific.
The changing a plurality of RX path that sent by the mobile wireless unit in the arrowband wireless channel cause the signal strength signal intensity of receiver end different thereupon.Difference is determined by the motion with respect to environment of environment and transmitter and receiver.Usually, the signal strength signal intensity of received fading signal can be described with rayleigh probability density function.The occurrence frequency of duration and spacing is by carrier frequency and the decision of removable cell rate.
Concerning some duration, decline may consume the energy of most of receiver signal.In a digital system, this may cause burst error, and at this moment, even average signal strength enough guarantees the low error rate when decline does not take place, but the error rate can become very high in a certain amount of time.
If two receivers receive the signal of being launched by same transportable transmitter, if distance surpasses several wavelength between the receiver, then the decline of the signal envelope in two receivers is irrelevant each other.Two receivers exist the single receiver of fading ratio to exist the decline possibility littler simultaneously.Space diversity reception to communicate has just utilized this point: the signal from two or more receivers is merged, and has reduced fading effect, and the antenna of receiver is discrete distribution in the space.Can adopt and surpass two receiver or branch road.Along with the increase of number of branches, fading effect further is reduced.
Now existing a large amount of technology are used to merge from the next signal of each branch road.One of the simplest technology is exactly to select diversity.In this technology, a central processing unit scans all branch roads, finds out the receiver with highest signal strength.At any time, central processing unit is imported as it with the highest branch road of signal strength signal intensity.By the relevant next signal of each branch road that merges, make combiner output signal-to-noise ratio maximum by adjusting the next gain of each branch road, can obtain higher gain.High specific known to Here it is merges.
In conventional system, a plurality of binary FSK signals transmit in a plurality of subchannels simultaneously, and a kind of method that receives and carry out the high specific merging is to utilize a large amount of narrow-band receivers, with they be tuned to each subchannel and from each branch road feed-in.The signal that comes from these receivers is fed into a conventional maximal ratio combiner then, for each subchannel produces combined signal.Unfortunately, along with the increase of subchannel number, the corresponding increase of the complexity of this conventional system and cost, the result causes after subchannel outnumbers some, and this conventional system is no longer suitable.
Therefore need a kind of method and apparatus of economy, be used to receive and merge a large amount of wireless signals that receive from a large amount of branch roads, wherein each wireless signal comprises moderate quatity to a large amount of subchannels.
One aspect of the present invention is a kind of method that diversity merges (diversity-combine) a large amount of wireless signals that is used for, the branch road of each wireless signal from a large amount of branch roads receives, each branch road is received corresponding antenna, and each wireless signal comprises a large amount of subchannels.This method may further comprise the steps: the wireless signal that each branch road from these branch roads is come carries out digitlization, generates a large amount of digitlization sample values correspondingly; Convert these digitlization sample values to a large amount of frequency-region signal.Each frequency-region signal is corresponding to a subchannel in these subchannels, and then corresponding to a branch road in a large amount of branch roads.Each frequency-region signal comprises the corresponding frequency domain sample value of a large amount of frequencies in a large amount of and each subchannel.This method also is included as the step that each branch road and each subchannel are determined weight coefficient.Weight coefficient is by instantaneous signal energy and noise power decision.Instantaneous signal energy and noise power are calculated by these frequency-region signals.This method also comprises: will be multiplied by this step of this weight coefficient with each branch road and the corresponding frequency-region signal of each subchannel, and be used for generating and each branch road and the corresponding a large amount of weighting frequency-region signals of each subchannel.In addition, this method comprises the step of merging corresponding to these weighting frequency-region signals of all branch roads of each subchannel, merges frequency-region signal for each subchannel produces a diversity.
The present invention is the device that a kind of diversity merges a large amount of radio signals on the other hand.The reception of each wireless signal from a large amount of branch roads, each branch road is received corresponding antenna respectively.Each wireless signal comprises a large amount of subchannels.This device comprises modulus (A/D) transducer that is coupled in a large number in these branch roads, is used for the wireless signal that each branch road from these branch roads comes is carried out digitlization, generates the corresponding digital sample value.This device also comprises the finger processor that is coupled to these A/D converters in a large number, and they are converted to a large amount of frequency-region signals with these digitlization sample values.In corresponding these subchannels of each frequency-region signal one, so corresponding with a branch road in these branch roads.Each frequency-region signal comprises a large amount of frequency domain sample values, and these frequency domain sample values are corresponding to a large amount of frequencies in each subchannel.Each finger processor comprises a weight coefficient unit, and each subchannel that is used to finger processor to receive the branch road of digitized wireless signals is determined a weight coefficient.This weight coefficient is by instantaneous signal energy and noise power decision.This instantaneous signal energy and noise power are calculated from these frequency-region signals.Finger processor comprises that also one is coupled to the multiplier of weight coefficient unit, is used for the frequency-region signal corresponding with this branch road and each subchannel is multiplied by weight coefficient, thereby generates a large amount of and branch road and the corresponding weighting frequency-region signal of each subchannel.This device comprises that also one is coupled to the combiner of these finger processor, is used to merge and corresponding these weighting frequency-region signals of all branch roads of each subchannel, merges frequency-region signal for each subchannel produces a diversity.
The present invention is a selective call base station on the other hand, and it is used in the selective call communication system.This selective call base station comprises: a controller is used to control this selective call base station; And a base station transmitter that is coupled to controller, be used for sending selective call signals to some selective call transceivers of this selective call communication system.This selective call base station also comprises a large amount of branch roads, and these branch roads comprise a large amount of antennas and corresponding a large amount of receiver unit thereof, are used for receiving a large amount of wireless signals of sending from the transmitter of these selective call transceivers.Each radio signal is by the some receptions in these receiver units, and the input of this receiver unit is from one in these antenna.Each wireless signal comprises a large amount of subchannels.These receiver units also are coupled to one and are used for the device that diversity merges these wireless signals.This device comprises modulus (A/D) transducer that is coupled to these branch roads in a large number, is used for the wireless signal that each branch road from these branch roads comes is carried out digitlization, generates a large amount of corresponding digital sample values.This device also comprises the finger processor that is coupled in a large number on these A/D converters, is used for these digitlization sample values are converted to a large amount of frequency-region signals.Each frequency-region signal is corresponding to a subchannel in these subchannels, thereby further corresponding to a branch road in these branch roads.Each frequency-region signal comprises a large amount of frequency domain sample values, and they are corresponding with a large amount of frequencies in each subchannel.Each finger processor comprises a weight coefficient unit, is used for determining that finger processor receives the weight coefficient of each subchannel of the branch road of digitized wireless signals.This weight coefficient is by instantaneous signal energy and noise power decision.This instantaneous signal energy and noise power are calculated by these frequency-region signals.This finger processor comprises that also one is coupled to the multiplier of weight coefficient unit, is used for being multiplied by this weight coefficient with this branch road and the corresponding frequency-region signal of each subchannel, thereby generates a large amount of and this branch road and the corresponding weighting frequency-region signal of each subchannel.This device comprises that also one is coupled to the combiner of these finger processor, is used to merge and corresponding these weighting frequency-region signals of all branch roads of each subchannel, thereby merges frequency-region signal for each subchannel produces a diversity,
Fig. 1 is the electrical block diagram of a selective call communication system, and it is corresponding to preferred implementation of the present invention.
Fig. 2 is the electrical block diagram of a selective call base station, and it is corresponding to preferred implementation of the present invention.
Fig. 3 describes is firmware and memory element in the finger processor, and it is corresponding to preferred implementation of the present invention.
Fig. 4 describes is firmware and memory element in the combiner, and it is corresponding to preferred implementation of the present invention.
Fig. 5 is the electrical block diagram of a selective call transceiver, and it is corresponding to preferred implementation of the present invention.
Fig. 6 is a sequential chart, illustration the bit combination of certain confirmation signal in the one group selection call transceivers, it is corresponding to preferred implementation of the present invention.
Fig. 7 is a signaling diagram, has described in this selective call base station, and from the frequency-region signal that a signal that receives produces, it is corresponding to preferred implementation of the present invention.
Fig. 8 is a frequency diagram, has described the signal structure of subchannel more than, and it is corresponding to preferred implementation of the present invention.
Fig. 9 is the operational flowchart of this selective call base station, and it is corresponding to preferred implementation of the present invention.
Figure 10 is the operational flowchart of this selective call transceiver, and it is corresponding to preferred implementation of the present invention.
Referring to Fig. 1, it is the electrical block diagram of a selective call communication system, corresponding to preferred implementation of the present invention, comprise a large amount of selective call base stations 102,102 are coupled in the conventional central controller 104 by communication link 106, and conventional central controller 104 is used to control this selective call base station 102.Central controller 104 is Motorola preferably, MPS2000 (TM) the paging control centre that Inc.of Schaumburg Illinios produces.Also can make central controller 104 with other similar control device.Each selective call base station 102 is launched wireless signals by a transmitting antenna 109 to a large amount of selective call transceivers 110.Selective call base station 102 receives wireless signal by a large amount of reception antennas 108 from these selective call transceivers 110, and a plurality of reception antennas 108 are coupled to each selective call base station 102.This reception antenna 108 that is coupled to each selective call base station 102 is relatively good during at least ten wavelength at interval each other, and so, the wireless signal that each reception antenna 108 receives is uncorrelated mutually substantially.Wireless signal comprises: the selective call address and the message that are transferred to selective call transceiver 110; And, from the affirmation message of these selective call transceiver 110 receptions.Be appreciated that selective call transceiver 110 can also generate message except acknowledge message.Central controller 104 is coupled to an input interface 112, and input interface 112 is used for from a local input equipment 114 as a conventional keyboard/display terminal, and public switched telephone network (PSTN) 116, receives the selective call information source.The selective call information source of coming from PSTN can be by such as generations such as ordinary telephone set 118, one a conventional computer/modulator-demodulator 120 or Common Facsimile Machine 122, and the method that they are coupled to PSTN116 is widely known by the people in present technique.
It is better that the selective call signaling protocol of being familiar with is adopted in transmission between selective call base station 102 and selective call transceiver 110, as Gray's sequence code (Golay Sequential Code) (GSC), or an international paging code (POCSAG) agreement.Adopt Binary Frequency Shift Keying (FSK) better from the net transmission that goes out of this selective call base station 102, be operated in 500 to 2,400 bits per second (bps) scopes.From this selective call transceiver 110, to pass to the networking transmission of selective call base station 102 and adopt arrowband binary FSK modulation better, modulation rate is transmitted on a subchannel at least at 100bps.Advantageously, it also can adopt other signaling protocol and FSK modulation system to carry out either direction or two-way transmission.Another favourable part is also can adopt other transmission rate, as long as the element duration of the transmission that networks is than big in that propagation delay time, thereby code element can be received synchronously.
Referring to Fig. 2, it is the electrical block diagram of this selective call base station 102, and corresponding to preferred implementation of the present invention, it comprises a conventional LI(link interface) 208, and LI(link interface) 208 is coupled to central controller 104 by communication link 106.Be stored in 204 li of conventional memories from selective call address and message that central controller 104 receives, store next transmission cycle always into.
LI(link interface) 208 is coupled to a controller 206, the operation of controller 206 controls one conventional transmitter 210.One is applicable to that example of the present invention is the MC6809 controller that controller adopts Motorola.The one conventional timing generator 216 that is coupled to this controller 206 provides a high precision clock, in order to maintenance system regularly, communicate and realize synchronously for the selective call communication system that comprises selective call base station 102 and these selective call transceivers 110,, the general personnel of present technique also understand this.
During operation, transmitter 210 sends the signal that comprises a paging kind of message with first frequency to these selective call transceivers 110 earlier when transmission cycle begins.Best, come paging receiving message by transmitter 210 predetermined (addressing) group selection call transceivers 110.As everyone knows, beep-page message was to use the suitable geocoding that this group selection call transceivers in these selective call transceivers 110 is carried out addressing before transmission.For example, according to preferred implementation of the present invention, when a certain group in these selective call transceivers 110 when paged, best, in some bits (code element) interval, receive this message this group selection call transceivers 110 each be transmitting acknowledgement response simultaneously basically, these bits (code element) are at interval on the interim arrowband subchannel that distributes of the second communication channel that is operated in second frequency.Best, confirm that the element duration of response is bigger than its propagation delay time, thereby code element can be received synchronously.A plurality of branch roads that each comprises a receiving element 214 and a reception antenna 108 respond in order to confirmation of receipt.As everyone knows, receiving element 214 demodulation confirmation signals are to generate a nearly baseband signal.
Corresponding to the at interval nearly baseband signal of the single code element (bit) of coming from each branch road be sampled digital signal by modulus (A/D) transducer 220 with this signal from analog conversion of signals (digitlization), the those skilled in the art of present technique check on this.The special-purpose A/D converter 220 of each branch road is better.In addition, A/D converter 220 is done to carry out 32,000 plural number sampling better at per second, and when bit rate was per second 100 bits, each was than peculiar 320 plural sample values like this.Receive the signal after A/D converter 220 conversions, the buffering through symbol interval is converted into and each symbol interval and the corresponding frequency domain sample value of each subchannel by a large amount of branch road digital signal processors (DSP) 218 then.Branch road DSP218 can comprise the digital signal processor such as the TMS3000 series of the DSP561000 of Motorola or Texas Instrument.Advantageously, also can adopt other similar DSP to make branch road DSP218, and can in this selective call communication system, adopt other sample frequency and bit rate.Be further appreciated that transmitter 210 can be placed on the place away from the miscellaneous part of this selective call base station 102, and the selective call communication system can comprise the base station that only can receive, it and selective call base station 102 are similar, just lack transmitter 210.
According to preferred implementation of the present invention, the corresponding frequency domain sample value of each symbol interval on each subchannel of branch road DSP218 conversion and storage and each branch road, and receive, change and store these frequency domain sample values continuously, till the frequency domain sample value of having stored a large amount of confirmation signals.Recover the digitlization sample value of each branch road, and convert thereof into frequency-region signal.Best, branch road DSP218 carries out rapid fourier change (FFT) to the time domain sample value of each symbol interval, thereby be that each branch road and each subchannel generate frequency-region signal, this frequency-region signal is produced by a large amount of affirmation signals, these confirmation signals are as synthetic time-domain signal, and those selective call transceivers 110 of generation response receive from a group selection call transceivers 110.Branch road DSP218 is then according to instantaneous signal energy and average noise power, for each branch road and each subchannel are determined a weight coefficient, and the frequency-region signal corresponding with each branch road and subchannel is multiplied by this weight coefficient.Then the weighting frequency-region signal of trying to achieve is merged in combiner DSP222, merge frequency-region signal for each subchannel produces a diversity.It is better when combiner DSP222 is similar to branch road DSP218 type.Timing generator 216 is coupled among branch road DSP218 and the combiner DSP222, handles the required synchronous and timing of these digitlization sample values to provide, and comprises a large amount of affirmation signals in these digitlization sample values.The operation of branch road DSP218 and combiner 222 will be gone through below.
Referring to Fig. 3, its is described is firmware and memory cell among the branch road DSP218, and branch road DSP218 is used to handle each subchannel of each branch road, and it is corresponding to preferred implementation of the present invention.Firmware unit comprises a weight coefficient unit 302, is used for the weight coefficient of each subchannel of definite branch road, and branch road DSP218 receives digitized wireless signals from this branch road.Weight coefficient determined by instantaneous signal energy and noise power, and instantaneous signal energy and noise power are calculated by a large amount of frequency-region signals.The weight coefficient unit comprises a noise estimator 304, its calculate with the corresponding frequency-region signal of branch road these subchannels protect the first average amplitude square value in the frequency band up and down, this branch road DSP218 is coupled on this branch road.The branch road noise power of noise estimator 304 estimation should equal the first mean square value amplitude, and the first mean square value amplitude is calculated from protection frequency band measurements, and further details is described below.Weight coefficient unit 302 also comprises signal energy estimation device 306, and it calculates and this branch road and the second average amplitude square value of the corresponding frequency-region signal of each subchannel in information band.This instantaneous signal energy is corresponding with branch road and each subchannel, should equal to calculate the second average amplitude square value.Weight coefficient unit 302 also comprises a calculator 308, and in order to calculate the weight coefficient of branch road and each subchannel, this weight coefficient equals to remove the last and corresponding noise power of this branch road with the square root of branch road and the corresponding instantaneous signal energy of each subchannel.
Branch road DSP218 also comprises a multiplier 310, and it is multiplied by weight coefficient with this branch road and the corresponding frequency-region signal of each subchannel, thereby generates and this branch road and the corresponding a large amount of weighting frequency-region signals of each subchannel.Branch road DSP218 also comprises a zero padding unit 312 and a rapid fourier change (FFT) unit 314, zero padding unit 312 is in order to increase to the digitlization sample value two integral number power, the rapid fourier change unit is in order to carrying out Fourier transformation to these digitlization sample values after zero padding, thus generate with each subchannel in the corresponding a large amount of frequency domain sample values of a large amount of frequencies.In addition, branch road DSP218 comprises that a windows units 316 is used for utilizing a Hanning window that these digitlization sample values are windowed before the digitlization sample value being increased to two integral number power.Best, this window mates with the amplitude Hanning window at transmitter place, disturbs to reduce adjacent channel, and this is very familiar in present technique.Branch road DSP218 also comprises a memory 318, is used for the intermediate value and the result of calculation of the temporary preferred embodiment for the present invention.
Referring to Fig. 4, its is described is firmware and memory cell among the combiner DSP222, corresponding to preferred implementation of the present invention, it comprises a homophase device 402, be used to make the pairing a large amount of weighting frequency-region signal homophases of all branch roads of each subchannel, thereby generate a large amount of weighting homophase frequency-region signals.Combiner DSP222 also comprises an adder 404, and these weighting homophase frequency-region signals that are used to add up merge frequency-region signal for each subchannel produces a diversity.Combiner DSP222 comprises that also a memory 406 is used for the intermediate value and the result of calculation of the temporary preferred embodiment for the present invention.The collaborative mode for each subchannel generation diversity merging frequency-region signal of branch road DSP218 and combiner DSP222 will be further described below.
Referring to Fig. 5, it is the electrical block diagram of this selective call transceiver, and corresponding to preferred implementation of the present invention, it comprises that one is used to intercept the antenna 502 of the wireless signal of sending, and these radio signals is coupled to the input of a conventional receiver 504.Best, these wireless signals belong to selective call (paging) message signals, and the auxiliary message as receiver address and numeral or word message and so on is provided.Yet, other call signaling form of being familiar with advantageously, the signaling that all has such as the signaling of having only tone or tone and sound is fit to use equally.
For example, although also can adopt other signaling format, we will suppose use POCSAG signaling format.When decoder/controller 506 receives the address, it and the one or more addresses that are stored in the programming code block (code memory) 522 are compared, if coupling just produces an alarm signal, remind the user to receive a selective call message or a paging.This alarm signal is directly delivered to conventional sound alarm equipment 514, produces a sound alarm; Or pass to the conventional alarm equipment 516 that touches, produce noiseless vibrating alert.Switch 520 allows select a sound alarm 514 or touch alarm 516 of selective call transceiver users, and implementation is widely known by the people in present technique.
The message information that receives later on is stored in the message memory 524, it is a conventional random access storage device preferably, and the user can visit with one or more switches 520, shows, these switches provide other additional function, as reset, read and delete or the like.Specifically, the suitable function of utilizing switch 520 to provide, the message of storage can recover to come out from message memory 524, and is handled by decoder/controller 506, shows that for conventional display 508 user just can read this message like this.Selective call transceiver 110 is received message, and it can provide from this selective call base station 102 of trend confirms response, is correctly received to inform its this message.Best, the user can import a message with the input equipment of being familiar with in switch 520 or other present technique, after the input message, decoder/controller 506 usefulness are carried out Methods for Coding to an address that obtains and are handled this message from the message that receives, and confirm response thereby generate.Sending this encoded affirmation response synchronously with radio signal, these radio signals are from the selective call base station 102 that produces this beep-page message.Present technique those skilled in the art extremely understand this technology.
Decoder/controller 506 preferably adopts a similar microcomputer of the microcomputer with MC68HC05 series, and this series mini computer is by Motorola, Inc.of Schaumburg, and Illinios produces.Advantageously, other microcomputer also can be used as decoder/controller 506, and message memory 524 also can be used as the part of decoder/controller 506.
Referring to Fig. 6, it is a sequential chart, illustration the bit combination 600 of certain confirmation signal of a transceiver in the one group selection call transceivers 110, it is corresponding to preferred implementation of the present invention.As previously mentioned, this confirmation signal is sent by selective call transceiver 110, and used bit rate is lower than the bit rate of 102 paging signals that send from the selective call base station, for example, the paging signal bit rate is in per second 500 to 2400 bit range, and confirmation signal is generally per second 100 bits.Bit combination 600 illustrations the affirmation signal of certain selective call transceiver 110, it transmits on certain subchannel.The description position 602,608,610 of bit combination 600 and 616-618 represent " 1 " of numeral, and position 604,608 and 612-614 represent " 0 " of numeral.Confirm in the response information that everybody worthwhile right foundation will transmit and deciding at each.
Referring to Fig. 7, it is a signaling diagram, has described according to the affirmation signal that receives, and produces a frequency-region signal in selective call base station 102, and it is corresponding to preferred implementation of the present invention.As previously mentioned, in certain symbol interval, each code element that selective call base station 102 receives on showing with subchannel is converted into corresponding frequency-region signal 702,712.Trunnion axis 704 is represented frequency, the vertical direction represent signal magnitude.Preferred modulation system is: for each corresponding selective call transceiver 110 distributes different subchannels simultaneously, and adopt binary FSK.Ten subchannels are for example arranged.The carrier frequency of each of these ten subchannels is positioned at a certain central shaft 750, and it indicates the center of each subchannel.Best, with the received carrier frequency of frequency domain window function estimation, determine the symbol value that receives by frequency-region signal, after this, measure also relatively and M the energy corresponding with each frequency of carrier frequency shift preset frequency.For example, one binary " 0 " is represented with frequency-region signal 702, and it is than central shaft 750 low scheduled volumes 706 of corresponding subchannel, and one binary " 1 " represents that with frequency-region signal 702 it is than central shaft 750 high scheduled volumes 708 of corresponding subchannel.
Referring to Fig. 8, frequency diagram 800 has been described the signal structure of subchannel more than, and it is sent by selective call transceiver 110, corresponding to preferred implementation of the present invention.This signal structure comprises a large amount of subchannel 806, and each subchannel comprises an information band 804, in information band protection frequency band 802 is arranged up and down.All energy of each subchannel 806 substantially as surpassing 95% energy, transmit in information band 804 the insides.Do not have tangible subchannel energy, as be less than 1% energy, in the 802 the insides transmission of protection frequency band.
Referring to Fig. 9, it is the operational flowchart of selective call base station 102, and corresponding to preferred implementation of the present invention, beginning is to power on 902.After the initialization, in a symbol interval, A/D converter 220 digitlizations 904 wireless signals generate a large amount of digitlization sample values corresponding with branch road, and these wireless signals are from the receiver unit of each branch road in this selective call base station 102.Then, branch road DSP218 converts these digitlization sample values to a large amount of frequency-region signals.In the corresponding a large amount of subchannels of each frequency-region signal one, and and then corresponding to the branch road that produces this signal.Each frequency-region signal comprises the corresponding frequency domain sample value of a large amount of frequencies in a large amount of and the subchannel.During the conversion beginning, window 908 for these digitlization sample values with a hanning window.As previously mentioned, this Hanning window preferably is being complementary with an amplitude Hanning window that is used in the transmitter 512, disturbs to reduce adjacent channel, and this is very ripe in present technique.Subsequent, branch road DSP218 becomes two integral number power to these digitlization sample value increases, and they are carried out rapid fourier change (FFT), generate a large amount of frequency domain sample values, a large amount of frequencies in each subchannel of these frequency domain sample values and each branch road are corresponding mutually.
Then, branch road DSP218 protects average amplitude square value in the frequency band, estimation 912 and the corresponding average noise power of each branch road by calculating with the corresponding frequency-region signal of each branch road up and down at these subchannels.Branch road DSP218 is by calculating and each branch road and the average amplitude square value of the corresponding frequency-region signal of each subchannel in information band estimation 914 and each branch road and the corresponding instantaneous signal energy of each subchannel.After this, branch road DSP218 calculates the weight coefficient of 916 each branch road and each subchannel, the square root that weight coefficient equals the instantaneous signal energy divided by with the corresponding average noise power of each branch road.Then, branch road DSP218 is multiplied by 918 respective weight coefficients with the frequency-region signal of each branch road and each subchannel correspondence, thereby generates a large amount of a large amount of weighting frequency-region signals corresponding with each branch road and each subchannel
Be appreciated that when each branch road noise frequency of estimation, also can use to surpass single symbol interval, as eight adjacent symbol intervals that rely on recently.By to the measurement of the protection band signal in several symbol intervals with ask average, the average noise that estimates is more accurate.
The weighting frequency-region signal is fed among the combiner DSP222.Combiner DSP222 makes the corresponding weighting frequency-region signal of all branch roads homophase 920 of these and each subchannel, thereby generates a large amount of weighting homophase frequency-region signals.Homophase is by the sample value of check with the corresponding amplitude square FFT of subchannel of each branch road, locatees then that the maximum of each subchannel realizes.Behind maximum location, produce the maximum place frequency index, all be saved in the memory 406 in the phase place of the weighting FFT at frequency index place and the branch road that generates this frequency index.Then, carry out mathematical phase shift with regard to the information band of the subchannel of all the other branch roads, all the other branch roads are meant and do not comprise the peaked branch road of subchannel.Make all branch roads that identical phase place be arranged producing the phase shift of doing in peaked frequency index place, this phase place be at the frequency index place corresponding to the phase place of the branch road of weighting FFT maximum, it is stored.Each subchannel is repeated the homophase operation, till the whole homophases of all subchannels.
Followed by homophase be combiner DSP222 these weighting homophase frequency-region signals that add up, be that each subchannel produces diversity and merges frequency-region signal.At this moment, the diversity of each subchannel merges frequency-region signal and can be used for carrier track and symbol detection.Whether combiner DSP222 check 922 needs more code element.If flow process is returned execution in step 904, carry out the digitlization of next symbol interval.If not, that is to say that if the code element of all predetermined quantities has received in the transmission cycle, 924 next transmission from selective call transceiver 110 are just waited in selective call base station 102 like that.
Best, carrier track and symbol detection are to adopt U.S. Patent application, and name is called " carrier track and symbol detection method and device ", and attorney docket is PT01684U, applies for that on September 30th, 1994 this patent at this as a reference by people such as Liberti.
Figure 10 is the operational flowchart with the corresponding selective call transceiver 110 of the preferred embodiment for the present invention.This selective call transceiver 110 is from selective call base station 102 receiving paging signals, and this is a step 1002; And, if address and message are arranged, it to be decoded, this is a step 1004.Paging signal preferably also comprises a transmission time, its same decoded comes out, and selective call transceiver 110 just can calculate time of delay before responding sending affirmation like this, and this is a step 1004.Come out by decoding from the paging signal that receives equally in the address of selective call base station 102, this is a step 1006.Selective call transceiver 110 is in delay always, up to have a message to enter maybe will to send confirm response till, this is a step 1008.Best, selective call transceiver 110 provides an option, can allow the user import message in confirming response, and this is very familiar in present technique, and this is a step 1010.If do not have the message input or also be less than launch time, process is followed execution in step 1008.Otherwise, if there is message to import, this message geocoding of selective call base station 102, this is a step 1012; Perhaps, if to launch time, confirmation signal is encoded with a default message.In some example, selective call transceiver 110 may not need from selective call base station 102 receiver addresses, just simply on preallocated subchannel, to selective call base station 102 transmission message.After receiving the decode confirmation message, selective call transceiver 110 is in delay always, and till will sending the affirmation response, this is a step 1014.Confirming that response sends to selective call base station 102, this is a step 1016 then.In this way, these selective call transceivers 110 almost response simultaneously each other.Owing to confirm that the used chip rate of response is low, so selective call base station 102 also almost is the code element of receiving simultaneously from these selective call transceivers 110.
Therefore, now should be very clear, preferred implementation of the present invention provides a kind of method and apparatus of economy, is used for the wireless signal that receives from a large amount of branch roads is in a large number received and the high specific merging, and wherein each wireless signal comprises a plurality of subchannels.Utilize a DSP of each branch road, carry out rapid fourier change, convert all a plurality of subchannels to frequency-region signal with economic method by wireless signal to each branch road of receiving.Merge for carrying out high specific, these frequency-region signals are weighted, use a combiner DSP homophase and a merging then, take this to provide a kind of diversity combiner of near optimal for multichannel decline arrowband fsk signal.
Claims (21)
1. one kind is used for the method that diversity merges a large amount of wireless signals, certain reception from a large amount of branch roads of each wireless signal, and each branch road is received corresponding antenna respectively; And each wireless signal comprises a large amount of subchannels; This method may further comprise the steps:
The wireless signal that each branch road from these branch roads is come carries out digitlization, generates a large amount of digitlization sample values correspondingly;
These digitlization sample values are changed, generated a large amount of frequency-region signals, each frequency-region signal is corresponding to a subchannel in these subchannels, and and then corresponding to a branch road in these branch roads; And each frequency-region signal comprises a large amount of frequency domain sample values, and these frequency domain sample values are corresponding to a large amount of frequencies in each subchannel;
For each branch road and each subchannel are determined a weight coefficient, this weight coefficient determined by instantaneous signal energy and noise power, and this instantaneous signal energy and noise power are calculated from these frequency-region signals;
The frequency-region signal corresponding with each branch road and each subchannel is multiplied by this weight coefficient, thereby generates a large amount of and each branch road and the corresponding weighting frequency-region signal of each subchannel; And
Merge these weighting frequency-region signals, merge frequency-region signal for each subchannel generates a diversity, these weighting frequency-region signals are corresponding with all branch roads of each subchannel.
2. the combining step that the process of claim 1 wherein may further comprise the steps:
Make these weighting frequency-region signal homophases, thereby generate a large amount of weighting homophase frequency-region signals, these weighting frequency-region signals are corresponding with all branch roads of each subchannel; And
These weighting homophase frequency-region signals that add up are that each subchannel generates diversity and merges frequency-region signal.
3. the process of claim 1 wherein that each subchannel comprises protects frequency band up and down, and these protection frequency bands comprise the frequency range that does not wherein have the tangible power transfer of these radio signals; And definite step wherein may further comprise the steps:
Calculate these frequency-region signals corresponding and protect the first average amplitude square value in the frequency band up and down at these subchannels with each branch road; And
Estimation and the corresponding noise power of each branch road, it should equal this first average amplitude square value.
4. the method for claim 3, wherein each subchannel comprises the information band of the frequency range that an energy that comprises the subchannel that these radio signals carry transmits nearly all therein; And definite step wherein is further comprising the steps of:
Calculate and each branch road and the second average amplitude square value of the corresponding frequency-region signal of each subchannel in this information band; And
Estimate the instantaneous signal energy corresponding with each branch road and each subchannel, it should equal this second average amplitude square value.
5. the method for claim 4, decision steps wherein also is included as the step that each branch road and each subchannel calculate this weight coefficient, this weight coefficient equal with the root mean square of each branch road and the corresponding instantaneous signal energy of each subchannel divided by with the corresponding noise power of each branch road.
6. the switch process that the process of claim 1 wherein comprises the steps:
These digitlization sample values are increased to two integral number power; And
These digitlization sample values behind rapid fourier change (FFT), generate with each subchannel in corresponding these frequency domain sample values of these frequencies.
7. the method for claim 6, switch process wherein also comprises: before these digitlization sample values being increased to two integral number power, with a Hanning window these digitlization sample values are windowed.
8. one kind is used for the device that diversity merges a large amount of wireless signals, certain reception from a large amount of branch roads of each wireless signal, and each branch road is received corresponding antenna respectively, and each wireless signal comprises a large amount of subchannels; This device comprises:
Be coupled to modulus (A/D) transducer of these branch roads in a large number, be used for the wireless signal that each branch road from these branch roads comes is carried out digitlization, form its corresponding a large amount of digitlization sample value;
Be coupled to the finger processor of these moduluses (A/D) transducer in a large number, be used for converting these digitlization sample values to a large amount of frequency-region signal, each frequency-region signal is corresponding with a subchannel of these subchannels, and and then corresponding with a branch road of these branch roads; And that each frequency-region signal comprises is a large amount of, with each subchannel in the corresponding frequency domain sample value of a large amount of frequencies; Each finger processor comprises:
One weight coefficient unit, each subchannel that is used to finger processor to receive the branch road of digitized wireless signals is determined a weight coefficient, this weight coefficient is by the decision of instantaneous signal energy and noise power, and this instantaneous signal energy and this noise power are calculated from these frequency-region signals; And
One is coupled to the multiplier of this weight coefficient unit, is used for being multiplied by this weight coefficient with this branch road and the corresponding frequency-region signal of each subchannel, thereby generates a large amount of and this branch road and the corresponding weighting frequency-region signal of each subchannel;
Wherein this device comprises that also one is coupled to the combiner of these finger processor, is used to merge and corresponding these weighting frequency-region signals of all branch roads of each subchannel, merges frequency-region signal for each subchannel generates a diversity.
9. the device of claim 8, wherein combiner comprises:
One homophase device is used to make and corresponding these weighting frequency-region signal homophases of all branch roads of each subchannel, to generate a large amount of weighting homophase frequency-region signals; And
One is coupled to the adder of this homophase device, these weighting homophase frequency-region signals that are used to add up, thus for generating diversity, each subchannel merges frequency-region signal.
10. the device of claim 8, wherein each subchannel comprises and protects frequency band up and down, these protection frequency bands comprise the frequency range that does not wherein have the tangible power transfer of these wireless signals; And weight coefficient unit wherein comprises a noise estimator, and it is coupled to the some branch roads in these branch roads, is used for: calculate with corresponding these frequency-region signals of this branch road and protect the first average amplitude square value in the frequency band up and down at these subchannels; And estimation and the corresponding noise power of this branch road, it should equal this first average amplitude square value.
11. the device of claim 10, wherein each subchannel comprises that one accounts for the information band of certain frequency scope, and nearly all subchannel energy that is carried by these wireless signals all transmits therein; And weight coefficient unit wherein comprises that also one is coupled to the some signal energy estimation devices in these branch roads, is used for: calculate and this branch road and the second average amplitude square value of the corresponding frequency-region signal of each subchannel in this information band; And estimation and this branch road and the corresponding instantaneous signal energy of each subchannel, it should equal this second average amplitude square value.
12. the device of claim 11, wherein the weight coefficient unit comprises that also one is coupled to the calculator of noise estimator and signal energy estimation device, be used to this branch road and each subchannel to calculate this weight coefficient, weight coefficient equal with the square root of this branch road and the corresponding instantaneous signal energy of each subchannel divided by with the corresponding noise power of this branch road.
13. the device of claim 8, wherein each finger processor also comprises:
One zero padding unit is used for these digitlization sample values are increased to two integral number power; And
One is coupled to rapid fourier change (FFT) unit of this zero padding unit, is used for carrying out rapid fourier changes through these digitlization sample values behind the zero padding, to generate the corresponding frequency domain sample value of these frequencies in these and each subchannel;
14. the device of claim 13, wherein each finger processor comprises that also one is coupled to the windows units of this zero padding unit, by utilizing a Hanning window, before these digitlization sample values being increased to two integral number power, these digitlization sample values are windowed.
15. one is used for the selective call base station of selective call communication system, this selective call base station comprises:
One is used to control the controller of this selective call base station;
One is coupled to the base station transmitter of this controller, is used for to the selective call transceiver transmit selective call signal that operates in this selective call communication system;
A large amount of branch roads, they comprise a large amount of antennas and corresponding a large amount of receiver unit, be used for receiving a large amount of wireless signals of sending from the transmitter of selective call transceiver, each wireless signal is by certain reception in these receiver units, the input of receiver unit is from certain antenna, and each wireless signal comprises a large amount of subchannels, these receiver units also are coupled to the device that a diversity merges these wireless signals, and this device comprises:
A large amount of modulus (A/D) transducer, they are coupled in these branch roads, are used for digitlization from the next wireless signal of each branch road of these branch roads, thereby generate corresponding a large amount of digitlization sample values;
A large amount of finger processor, they are coupled to these A/D converters, be used for these digitlization sample values are converted into a large amount of frequency-region signals, each frequency-region signal is corresponding to a subchannel in these subchannels, and and then corresponding to a branch road in these branch roads, and, each frequency-region signal comprise with each subchannel in a large amount of corresponding a large amount of frequency domain sample values of frequency; Each finger processor comprises:
One weight coefficient unit, each subchannel that is used to finger processor to receive the branch road of digitized wireless signals is determined a weight coefficient, this weight coefficient determined by instantaneous signal energy and noise power, and this instantaneous signal energy and noise power are calculated from these frequency-region signals; And
One is coupled to the multiplier of this weight coefficient unit, is used for being multiplied by this weight coefficient with this branch road and the corresponding frequency-region signal of each subchannel, thereby generates and this branch road and the corresponding a large amount of weighting frequency-region signals of each subchannel;
Wherein this device comprises that also one is coupled to the combiner of these finger processor, is used to merge and corresponding these weighting frequency-region signals of all branch roads of each subchannel, thereby merges frequency-region signal for each subchannel produces a diversity.
16. this selective call base station of claim 15, combiner wherein comprises:
One homophase device is used to make and corresponding these weighting frequency-region signal homophases of all branch roads of each subchannel, thereby generates a large amount of weighting homophase frequency-region signals; And
One is coupled to the adder of this homophase device, with its these weighting homophase frequency-region signal that superpose, is that each subchannel produces diversity and merges frequency-region signal.
17. the selective call base station of claim 15, wherein each subchannel comprises and protects frequency band up and down, and these protection frequency bands comprise the frequency range that does not wherein have the tangible power transfer of these wireless signals; And; weight coefficient unit wherein comprises a noise estimator; it is coupled to some in these branch roads; be used to calculate with corresponding these frequency-region signals of this branch road and protect the first average amplitude square value in the frequency band up and down at these subchannels; it also is used for estimation and the corresponding noise power of this branch road, and it should equal this first average amplitude square value.
18. the selective call base station of claim 17, wherein each subchannel comprises an information band, this frequency band comprise that these wireless signals carry the frequency range transmitted nearly all thereon of energy; And, weight coefficient unit wherein also comprises signal energy estimation device, it is coupled to some in these branch roads, be used to calculate the second average amplitude square value in this information band with this branch road and the corresponding frequency-region signal of each subchannel, it also is used to estimate the instantaneous signal energy corresponding with this branch road and each subchannel, and it should equal this second average amplitude square value.
19. the selective call base station of claim 18, wherein this weight coefficient unit also comprises a calculator, it is coupled on noise estimator and the signal energy estimation device, be used to this branch road and each subchannel to calculate weight coefficient, this weight coefficient equals square root with this branch road and the corresponding instantaneous signal energy of each subchannel divided by the noise power corresponding with this branch road.
20. the selective call base station of claim 15, wherein each finger processor also comprises:
One zero padding unit is used for these digitlization sample values are increased to two integral number power; And
One rapid fourier change (FFT) unit, it is coupled to this zero padding unit, is used for these digitlization sample values behind zero padding are carried out rapid fourier changes, thereby generates these and interior corresponding these frequency domain sample values of these frequencies of each subchannel.
21. the selective call base station of claim 20, wherein each finger processor comprises that also one is coupled to the windows units of this zero padding unit, it is with a Hanning window, before these digitlization sample values being increased to two integral number power, these digitlization sample values is windowed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95195854 CN1161765A (en) | 1994-10-24 | 1995-10-24 | Method and apparatus for fast fourier transform based maximal ratio combining |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/327,753 | 1994-10-24 | ||
| CN 95195854 CN1161765A (en) | 1994-10-24 | 1995-10-24 | Method and apparatus for fast fourier transform based maximal ratio combining |
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| CN1161765A true CN1161765A (en) | 1997-10-08 |
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| CN 95195854 Pending CN1161765A (en) | 1994-10-24 | 1995-10-24 | Method and apparatus for fast fourier transform based maximal ratio combining |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1104785C (en) * | 1997-03-05 | 2003-04-02 | 富士通株式会社 | Position diversity reception, base station main frame apparatus and processing method for receiving signal |
| CN100372246C (en) * | 2005-01-05 | 2008-02-27 | 联发科技股份有限公司 | System and method of processing frequency-diversity signals with reduced-sampling-rate receiver |
-
1995
- 1995-10-24 CN CN 95195854 patent/CN1161765A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1104785C (en) * | 1997-03-05 | 2003-04-02 | 富士通株式会社 | Position diversity reception, base station main frame apparatus and processing method for receiving signal |
| CN100372246C (en) * | 2005-01-05 | 2008-02-27 | 联发科技股份有限公司 | System and method of processing frequency-diversity signals with reduced-sampling-rate receiver |
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