CN104320159B - communication system and method of operating a communication system - Google Patents
communication system and method of operating a communication system Download PDFInfo
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- CN104320159B CN104320159B CN201410542287.0A CN201410542287A CN104320159B CN 104320159 B CN104320159 B CN 104320159B CN 201410542287 A CN201410542287 A CN 201410542287A CN 104320159 B CN104320159 B CN 104320159B
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Abstract
A communication system and a method of operating a communication system, wherein the method of operating a communication system comprises transmitting a communication signal comprising predetermined training symbols suitable for channel estimation from a first communication device to a second communication device; scanning, at the second communication device and during simultaneous reception of communication signals, a receiver frequency range for a notch band comprising noise above a predetermined noise level; wherein during transmission of the predetermined training symbols, the receiver frequency range is scanned and successive training symbols are transmitted at different time distances from each other.
Description
The application is divisional application, the Application No. 201080031044.0 of its original bill application, the applying date
It is on July 1st, 2010, invention entitled " utilizing the communication system of adaptive frequency trap ".
Technical field
Embodiments of the invention relate to the use of the logical of adaptive frequency trap (frequency notching)
Communication system, and relate to the self adaptation of transmit power, for the noise measurement during subsidiary communications.
Further embodiment relates to the use of adaptive frequency trap and communicating that self adaptation transmit power manages
The equipment of system and utilize adaptive frequency trap and the management of self adaptation transmit power for operation
Communication system is with the method communicating the noise measurement of period.
Background technology
PLT of the prior art (electric lines of force telecommunications) may result in the restriction that coexists with broadcast service.Go out
Version thing ETSI TS 105 578；Electric lines of force telecommunications；“Coexistence between PLT modems
and short wave radio broadcasting services”；ETSI 2008 describes a kind of self adaptation
Frequency trap technology, on the one hand, it has data throughout and QoS (service quality) requirement
Minimum impact, and on the other hand, its minimizing is wireless at PLT (electric lines of force telecommunications) and shortwave
Interference between electricity broadcast.
Communication and electric lines of force wiring are used as bilateral antenna, wherein, generally transmission function or antenna gain pair
Signal is launched and is identical for signal reception.Be suitable to receive broadcast singal and send out on the same frequency band
The communication of the number of delivering letters and electric lines of force wiring may interfere with and connect broadcast singal at radio receiver
Receive.The adaptive notch suppression use to following frequency band, in these frequency bands, broadcast singal is by communicating
System detects.
PLT modem detects the existence of broadcast singal by perception " noise ".In the application
In the use of term noise followed in ETSI TS 105 578 publication determined by terminology, its
In, noise is included in trunk cable (mains cabling) radio signals gathered.
As described in EP 2 020 758 A1, can receive by such as measuring in multiple narrow-bands
Signal power detects the broadcast singal on electric lines of force.
After identifying the frequency band used by receivable radio signals, PLT transmitter
Identified frequency band is omitted by trap (notch) being inserted into transmission frequency spectrum.Can be closed by offer
Suitable notch filter (notching filter) is (such as, with the digital filtering of suitable filter factor
Device) apply trap.
WO 2008/101593 A1 describes based on multi-carrier modulation technology and adaptive frequency trap
Sending method, wherein, neighbouring by the frequency band of trap and this carrier wave quilt decayed by notch filter
Amplify.
The purpose of invention is to provide for reliably and in time detecting the broadcast singal in communication system
The method and apparatus entered.
By communication system of the present invention, for the communication equipment of communication system and be used for grasping
The method making communication system, this purpose is implemented.Specific embodiment asks for an interview detailed description of the invention part.
From below in conjunction with the accompanying drawing description to embodiment, the details of invention will be apparent from.
Summary of the invention
It is an object of the present invention to provide for reliably and in time detecting the broadcast singal in communication system
The method and apparatus entered.
According to an aspect of the invention, it is provided a kind of communication system (100), including: first connects
Receipts machine unit (120), this first receiver unit (120) is connected also with transmission channel (105)
It is configured to determine that the signal power at upper the first signal of communication received of described transmission channel (105),
Further, this first receiver unit (120) includes noise detection unit (126b),
First data transmitter unit (110), this first data transmitter unit (110) and described transmission channel
(105) it is connected and is configured to send the first signal of communication or the second signal of communication, wherein, by
The gain of the signal of communication that described first data transmitter unit (110) exports is controlled, and
First control unit (151), this first control unit (151) is configured to respond to make a reservation for
Signal power and control the gain of described first data transmitter unit (110) so that signal power is enough
High to guarantee that the safety to signal of communication receives, and so that signal power is of a sufficiently low with to described
The measurement to the noise of predetermined noise level of the reception period auxiliary of the first signal of communication；
Wherein, described noise detection unit (126b) is configured at the reception period to signal of communication
Measure the noise on the predetermined noise level in signal of communication.
According to another aspect of the present invention, it is provided that a kind of communication equipment for communication system
(101-103,401), including: receiver unit (120,420), this receiver unit (120,
420) can be connected with transmission channel (105,405) and be configured to determine that at described transmission channel
The signal power of (105,405) upper first signal of communication received, and, this receiver unit (120,
420) noise detection unit (126b), data transmitter unit (120,420), this transmitter list are included
Unit (120,420) can be connected with described transmission channel (105,405) and be configured to described
Transmission channel (105,405) is upper sends the first gain control signal；And control unit (152,
452), this control unit (152,452) is connected with described receiver unit and described data transmitter unit
If connecing and being configured between signal power and the predetermined noise level of described first signal of communication
Ratio is higher than by the first predetermined threshold water given by the dynamic range of analog digital converter (124)
Flat, then initiate the transmission to described first gain control signal, this analog-digital converter (124)
It is included in described receiver unit (120) and is configured to the signal of communication that conversion is received；Its
Described in noise detection unit (126b) be configured to the reception period of signal of communication is being measured communication
The noise on predetermined noise level in signal.
According to another aspect of the present invention, it is provided that a kind of method operating communication system, including:
At receiver unit (120,420) place, determine via transmission channel (105,405,505) institute
The signal power of the signal of communication received；And at data transmitter unit (110,510) place, in response to
Determined by signal power, adjust the signal power of described signal of communication so that signal of communication level with
The ratio of predetermined noise level, should equal to or less than the dynamic range of analog-digital converter (124)
Analog-digital converter (124) is included in described receiver unit (120) and is configured to turn
Change described signal of communication；And at described receiver unit (120,420) place and to signal of communication
While reception period, for the notch band of the noise included higher than described predetermined noise level, sweep
Retouch receiver frequency range.
Accompanying drawing explanation
Figure 1A shows the schematic frame of the wired or wireless communication system according to inventive embodiment
Figure, this wired or wireless communication system includes the receiver list being integrated in the first modem device
Unit and the variable gain amplifier data transmitter unit being integrated in second modem equipment.
Figure 1B shows the schematic block diagram of the modem device for wired communication system,
Wherein, according to another embodiment of invention, receiver unit and variable gain amplifier data transmitter unit
It is integrated in identical modem device.
Fig. 2 shows the receiver including noise measurement unit of another embodiment according to invention
The schematic block diagram of unit.
Fig. 3 show according to invention another embodiment include adaptive notch filter unit
The schematic block diagram of data transmitter unit.
Fig. 4 shows the modulatedemodulate for determining the signal power receiving signal according to embodiment
Adjust the schematic block diagram of device equipment.
Fig. 5 shows the modem sending gain with adjustable according to another embodiment
The schematic block diagram of equipment.
Fig. 6 shows the communication of the feature for illustrating the communication equipment according to other embodiments and dashes forward
The simplification time diagram of the lead code sent out.
Fig. 7 shows when the synchronization of the feature illustrating the communication equipment according to other embodiments
The simplification time diagram of section.
Fig. 8 A is the flow process of the simplification of the method for operating communication system according to another embodiment
Figure.
Fig. 8 B be according to another embodiment with reference to mutual Gain tuning for operating communication system
The flow chart of the simplification of method.
Fig. 8 C be another embodiment according to the change distance utilized between training symbol for operating
The flow chart of the simplification of the method for communication system.
Fig. 9 shows the wired or wireless communication system utilizing training symbol to carry out channel estimation
Schematic block diagram.
Detailed description of the invention
Figure 1A shows communication system 100.Communication system 100 can be wirelessly or non-wirelessly communication system
System, such as, xDSL (general digital subscribers feeder) or DVB-C2 (DVB-cable).
According to an embodiment, communication system is based on OFDM (OFDM) modulation scheme.According to
Another embodiment, communication system 100 is to utilize distribution wire (power distribution wire) to enter
The system of row data communication.Such as, communication system 100 be power line communication (PLC), main line lead to
Letter, electric lines of force telecommunications (PLT), broadband power line (BPL) or electric power band or utilization superposition respectively
Electric lines of force networking (PLN) of the MCW modulated carrier wave on the electric lines of force of 50Hz or 60Hz alternating current.
Transmission line 105 represents the transmission channel between two communication equipments of wired communication system.Communication equipment
Can be transmitter apparatus and receiver device, or two bi-directional device (modem).
Communication system 100 includes the first receiver unit 120 being connected to transmission line 105.First connects
Receipts machine unit 120 can include for connecing of being amplified by the signal of communication 121 received on transmission line 105
Folding and unfolding big unit 122, the ADC being used for sampling the signal of communication 123 amplified (simulate number
Word transducer) 124, and it is used for being digitally processed signal of communication 125 that (decoding) sampled
Decoder element 126.Decoder element 126 includes noise detection unit, this noise detection unit quilt
It is configured to during receiving signal of communication measure in the communication signal on predefined noise level
Noise.
Predefined noise level can be defined by the specification of corresponding communication system 100.Such as, generally,
Communication system 100 EMC to be followed (Electro Magnetic Compatibility) requirement, and therefore, noise and signal
Level is typically specified as directly related with emitting side and/or injection side more or less.Such as, ETSI
In signal level defined in ETSI TS 102 578 V1.2.1 (2008-08), this signal level instruction nothing
The existence of the line signal of telecommunication also triggers omission frequency band from the transmission frequency spectrum of PLT equipment.But,
In other sights, the detection to noise level (that is, relative to the weak signal for signal of communication) can
Relevant to other requirements.
First receiver unit 120 can include or may not include for avoiding amplifier overload or ADC
The saturated AGC (automatic growth control) of 124.First receiver unit 120 is configured to determine that
The signal power of the signal of communication 121 received on transmission line 105.
By example, the first receiver unit 120 includes detector unit 128, this detector unit 128
Be suitable to the signal level (such as, signal power level) of signal of communication 121 that assessment received defeated
Go out to represent the control signal 129 of the signal power of the signal of communication 121 received.For generating control
Signal 129, detector unit 128 can only be assessed as with the signal of communication received shown in continuous lines
121 or the signal of communication 123 of amplification as shown by dashed lines, the signal of communication 125 sampled or
Two or more combination in decoded signal of communication or these signals.Control signal 129
Each signal can be described whether more than the first predetermined threshold.
Communication system 100 also includes the first data transmitter unit 110 being connected to transmission line 105.First
Data transmitter unit 110 is configured on transmission line 105 send signal of communication, wherein, by first
The gain sending the signal of communication that machine unit 110 exports is controlled.Such as, the first data transmitter unit 110
Including: sending coding unit 112, it is according to modulation scheme (such as, OFDM (orthogonal frequency division multiplexing
With) modulation scheme) digitally modulate (coding) data stream 111；For by encoded data stream
It is converted into the DAC (digital analog converter) 114 of analogue signal；And amplification analog communication signal
To generate the variable gain transmission amplifier unit 116 of the signal of communication via transmission line 105 transmission.
The gain of amplifier unit 116 is adjustable.
Communication system 100 also includes the first control unit 151, and this first control unit 151 is configured
For in response to signal level determined by the first receiver unit 120, controlling the first transmitter list
The gain of unit 110, such as, sends the gain of amplifier unit 116.
As PLT, the loss of the communication channel of communication system has high variance, and pole
Depend on by force frequency.Average attenuation depends on that the attribute of wiring is (such as, in the feelings of PLT strongly
In shape, main line wiring attribute), be connected to the various electronic installations of main line impact and modulation
Distance between demodulator.Therefore, PLT modem is generally of the total dynamic of up to 90dB
State scope, at receiver side, ADC and AGC of receiver amplifier contribute to this scope.
Generally, the transmission amplifier at sender side sends by total power, and, at receiver side
AGC prevents ADC from transshipping.But, when receiving strong signal of communication, it is difficult to detection and the letter that communicates
Number noise simultaneously received and the radio signals being included in noise.According to embodiment, send
Amplifier is configured such that its transmit power can adjust in such a way: leading at receiver side
The signal power of letter signal is for being sufficiently high for the error free reception of signal of communication and of a sufficiently low
Make when broadcast singal sufficiently strong so that be disposed in the radio receiver near communication system can
During reception, can detect that the entrance of broadcast singal.
Transmission amplifier gain and channel transfer functions determine the sensitivity of receiver unit.According to showing
Example, if needing to measure the noiselike signal of such as-95dBm, then the sensitivity of receiver unit is wanted
It is arranged at a relatively high.If sending amplifier to reduce signal power, then the reception threshold value of receiver can
It is arranged to of a sufficiently low.Embodiment assists the adaptive power management at sender side, and, enable
Reliable noise measurement during the data communication of receiver side.
Such as, publication ETSI TS 105 578 specifies power line communication modem to detect
Radio signals, and, 15 after receivable radio broadcast service physical presence
Within Miao, activate corresponding trap.If ETSI TS 105 578 also defines receivable signal power
At least-95dBm and at least above noise floor (noise floor) 14dB, then exist shortwave without
Line electricity broadcast singal.For there is the whole time that short-wave radio is broadcasted, trap should keep continuing
Ground is movable.In being widely applied, utilize receiver unit 120, transmitter list according to embodiment
The electric line communication system of unit 110 and the first control unit 151 makes PLT equipment reliably to survey
Measure noise and detect the entrance of broadcast singal rapidly.
Figure 1A relates to communication system 100, wherein, receiver unit 120 and data transmitter unit 110
It is integrated in two different communication equipments.Communication system 100 according to Figure 1A includes the first tune
Modulator-demodulator equipment 101 and second modem equipment 102.Each modulation /demodulation equipment 101,
102 can include processing unit 150, and this processing unit 150 is for processing via transmission line 105, entering one
Walk via data line 159 or from the data of sensor reception, and, this processing unit 150 is used
Will be via transmission line 105, further via data line 159 or to actuator in preparation
(actuator) data sent.By way of example, modem device 101,102 can be band
Having the PLT equipment of the same-interface to transmission line 105, in this case, transmission line 105 is by main line
There is provided.
Second modem equipment 102 includes first receiver unit the 120, second control unit 152
With the second data transmitter unit 110.The second data transmitter unit 110 in second modem equipment 102
The first data transmitter unit 110 can being equal in the first modem device 101, or permissible
It is equal to the most therewith.Second control unit 152 be connected with the first receiver unit 122 (such as, with
Detector unit 128 is connected) and be connected with the second data transmitter unit 110.When the communication received
When the detected signal level of signal 121 is more than the first predetermined threshold levels, the second control unit
152 are configured to initiate the transmission of the gain control signal on transmission line 105.Second control unit
152 can be special circuit (such as, ASIC (special IC)), or can be incorporated in process
In unit 150, and, it may include hardware element can be maybe to operate in the journey in processing unit 150
A part for sequence.
First modulation /demodulation equipment 101 includes first data transmitter unit the 110, first control unit 151
With the second receiver unit 120, this second receiver unit 120 can be equal to the second modulation /demodulation
First receiver unit 120 of device 102, or can not be equal to therewith.Second receiver unit 120
It is connected with transmission line 105.First modem device 101 is on the second receiver unit 120
Receive gain control signal.In response to the second receiver unit by the first modem device 101
120 gain control signals received, the first control unit 151 controls the first modem device
The gain of the first data transmitter unit 110 in 101.First control unit 151 can be special circuit
(such as, ASIC (special IC)), or can be incorporated in the first modem device 101
Processing unit 150 in, and, it may include hardware element can be maybe to operate in processing unit 150
In the part of program.
Such as, if gain control signal indicates the first reception in second modem equipment 102
Signal level detected by machine unit 120 more than the first predeterminated level, then reduces the first modulatedemodulate
Adjust the gain at the first data transmitter unit 110 in device equipment 101.Such as, can decreasing gain, directly
Being generated to there is no other gain control signal.According to other examples, gain control signal bag
Include the information of the signal power about reception signal and the distance of the first predetermined threshold.When at sender side
Gain become to be connect at the receiver unit 120 in too low and second modem equipment 102
Receive signal of communication 121 cannot the most evaluated time, further gain control signal can be generated.
Figure 1B relates to communication system 100, wherein, above-mentioned first receiver unit 120 and first
Machine unit 110 is sent to be integrated in identical modem device 103.Modem device 103
May also include processing unit 150, this processing unit 150 is similar to be retouched about Figure 1A for process
The data stated.Modem device 103 includes being connected to the first receiver unit 120 (such as,
It is connected to detector unit 128) and the control unit 153 of the first transmitting element 110.
Control unit 153 is suitable to receive about following information: set by another in communication system 100
The standby communication being sent and being received at the first receiver unit 120 of modem device 103
The signal power of signal.Control unit 153 is additionally configured to adjust sending out of modem device 103
Send the gain of machine unit 116.Such as, during initialization period, two equipment can use approximately equal
Gain send, and, each equipment adjusts its gain in response to received signal power.Cause
This, even if gain is controlled such that while to signal of communication during transmission, signal power is enough
Big to guarantee that the safety to signal of communication receives, and, signal power is of a sufficiently low the sensitiveest with auxiliary
Noise measurement.
Gain tuning can be delayed by some communication cycles, in order to strong to other equipment Inspections of communication system
Signal the respectively chance of slow fall (ramp down) transmission amplifier gain in they each sides.
Fig. 2 shows in detail the receiver unit 120 according to embodiment.In receiver unit 120,
Decoder element 126 includes converter unit 126a, and this converter unit 126a receives the communication sampled
Signal 125, and perform FFT (fast Fourier transform), it is included in signal of communication for acquisition
In the range value of multiple frequencies.Frequency and Amplitude value represents the frequency spectrum to the signal of communication 125 sampled
(frequency spectrum) 127 is described.
Based on frequency spectrum 127, demodulator unit 126c can be such as by utilizing QAMD (quadrature amplitude
Modem) perform the demodulation to the digital signal sampled, in order to and it is logical that acquisition is received
The baseband representation of letter signal 121.Error correction unit 126d can be at the base band table of the signal of communication received
Show execution error correction method.Baseband representation can be forwarded to processing unit.Such as based on frequency spectrum 127,
The measurement of noise detection unit 126b is included in the noise in received signal of communication.Wide when detecting
When broadcasting signal entrance, noise detection unit 126b generates notching control signal 211.Notching control signal
211 include the information being detected the frequency at place about broadcast singal.
Frequency spectrum 127 can be additionally used in or at least can help to measure or determine as indicated by with dotted line a
The signal power of the signal of communication received in detector unit 128.Alternately or additionally, received
Signal of communication 121, the signal of communication 123 amplified or the signal of communication 125 sampled can by with
In determining such as the signal power by the signal of communication received indicated by line d, line c and line b.
Fig. 3 shows in detail data transmitter unit 110.Data stream 111 is sent to entangle from processing unit
Wrong unit 112a, this error correction unit 112a inserts code redundancy according to error correction scheme.Obtained by
Data stream can be modulated in modulator unit 112b, and this modulator unit 112b may utilize multiple load
Wave frequency, such as, QAM (quadrature amplitude modulation).Can use and provided by Notch Control Unit 112e
Coefficient come to each modulated carrier signal weight.Known may be in this stage by the carrier wave of trap
It has been suppressed.All carrier waves not omitted are sued for peace by converter unit 112c, and apply IFFT (inverse
Fast fourier transform) to generate time-domain signal.It addition, this signal can be by trap wave unit wave filter 112d
Filtering is to overcome weak side cyclic inhibition (weak side loop suppression), and this trap wave unit is filtered
Ripple device 112d also can be controlled by Notch Control Unit 112e.
Notch filter unit 112d can decay adjacent to the frequency of notch band, wherein, neighbouring load
Ripple also can be attenuated.This decay can be compensated by the pre-amplification of the corresponding carriers in converter unit 112c,
This converter unit 112c can be such as by being multiplied by the predetermined amplitude factor by each affected carrier wave
The amplitude of each carrier wave is each set.This multiplication makes carrier wave increase or amplifies and in notch filter unit
The attenuation of this carrier wave in 112d is identical or the most approximately uniform amount.In notch filter unit
The pad value of each carrier wave in 112d can be led from the frequency response of notch filter unit 112d
Go out.
Notch Control Unit 112e is connected with notch filter unit 112d and converter unit 112c.
Notch Control Unit 112e can be configured to arrange notch filter unit 112d filter coefficient,
Calculate the frequency response of notch filter unit 112d, and, by setting in converter unit 112c
The amplitude factor putting correspondence increases or amplifies the carrier wave decayed.Notch Control Unit 112e receives
The notching control signal 211 such as generated by noise measurement unit 126b of Fig. 2.Real according to another
Executing example, another measuring unit being configured to spy upon on transport channels the entrance of noise may be disposed at
In the input path of communication equipment.
Fig. 4 shows communication equipment 401, and this communication equipment 401 is configured to detect broadcast singal
Entering and send gain control signal to another communication equipment, this another communication equipment is to communication equipment
401 send signal of communication.Communication equipment 401 may participate in communication system as described with respect to figure ia
In system.
Communication equipment 401 can be the equipment of wired or wireless communication system.Receiver unit 420
May be connected to transmission line 405 or antenna element.Receiver unit 420 can determine at transmission line 405
Or the signal power of the signal of communication received on antenna element, and including noise detection unit, this is made an uproar
Sound detection unit is configured to during receiving signal of communication measure in signal of communication higher than predetermined noise
The noise of level.Data transmitter unit 410 can be connected with transmission line 405 or antenna element, this antenna
Element could be for the antenna element that signal receives.Data transmitter unit 410 is configured at transmission line
405 or antenna element on send gain control signal.Control unit 452 and receiver unit 420 and
Data transmitter unit 410 is connected.When the signal power of the signal of communication received is more than the first predetermined threshold
During value level, control unit 452 can initiate the transmission to gain control signal 462.Gain control
Signal 462 can be inserted in the data stream generated in the processing unit 450 of communication equipment 401
In 411, to utilize data transmitter unit 410 to send.Data transmitter unit 410 can be with having
The usual data transmitter unit sending amplifier unit 416 of fixed gain.Other element can be corresponding
In about the equivalent element described by figure before.
According to another embodiment, the gain of data transmitter unit 410 (such as, sends amplifier unit
The gain of 416) can be adjustable.Then, receiver unit 420 is additionally configured to receive and increases
Benefit control signal, and, another control unit can be connected to receiver unit 420 and transmitter list
Unit 410 both, and can be configured to respond to received gain control signal control send increase
Benefit.
Fig. 5 shows communication equipment 501, and this communication equipment 501 is configured to receive gain control letter
Number and in response to gain control signal adjust its send gain.
According to embodiment, communication equipment 501 includes data transmitter unit 510, and its gain (such as, is sent out
Send the gain of amplifier unit 516) it is adjustable.Receiver unit 520 is configured to receive and increases
Benefit control signal, and include noise detection unit, this noise detection unit is configured in reception logical
Measure during letter signal in the communication signal higher than the noise of predetermined noise level.Control unit 551 quilt
It is connected to both receiver unit 520 and data transmitter unit 510, and it can be in response to being received
Gain control signal and control send gain.Other element may correspond to be retouched about figure before
The equivalent element stated.
Fig. 6 refer to reference to Figure 1A, 1B, communication equipment described by 4 and 5 101,102,103,
401, the further feature of 501.Also may be used according to further embodiment, processing unit or data transmitter unit
It is configured to the received training symbol sending and/or assessing in the lead code of communication bursts.Training symbol
Can be used for determining or measuring the channel transfer functions of transmission channel.
According to embodiment, processing unit includes channel estimator unit, and this channel estimator unit is joined
It is set to compare received training symbol and reference marks, for determining the communication such as communicated
The channel transfer functions of the transmission line between equipment.Channel transfer functions can be used for fitting in communication and sets
Wave filter in standby data transmitter unit and/or receiver unit, and can be used for estimating signal to noise ratio.As
Fruit can perform noise measurement during leading code before sending, then can ensure the safety of the communication resource.According to reality
Executing example, by the variance between the training symbol that assessment is received, noise measurement is performed.
Fig. 6 schematically shows the lead code 600 of communication bursts.At the head of lead code, can set
Being equipped with synchronizing sequence 602, this synchronizing sequence 602 can be used for the time synchronized of reception equipment.Then,
Multiple training symbols 606 are followed thereafter, and wherein, each training symbol 606 can be to protect interval 604
Headed by, this protection interval 604 can be provided that so that transmitting relative to Multipath Transmission robust.For example,
Protection interval 604 can include the copy of the fragment of training symbol 606.Each protection interval 604 can have
There is the first length l1, and each training symbol 606 can have the second length l2.According to embodiment, often
Preceding training symbol 606 is directly followed at individual posterior protection interval 604.However it is possible to be difficult to inspection
Survey the noise frequency of the multiple of training symbol repetitive rate, because this noise does not increase received instruction
Practice the variance between symbol 606.
According to another embodiment, about length, protection interval 604 can be different.Such as, each protection
Interval 604 has another length.According to other embodiments, the modification space 610 of different length can quilt
It is inserted between each training symbol 606 and the interval of protection in succession 604.During gap 610,
Signal is not had to be sent.This avoids the constant sine wave of the multiple that frequency is training symbol repetition rate
Interference, it can affect each training symbol 606 in an identical manner.Training symbol 606 can be changed
Between distance so that the fewest signal can affect all training symbols in an identical manner
606.The change of gap length and can protect the change group of the length (persistent period) at interval (604)
Close.According to other embodiments, additionally or in the alternative, the length of training symbol (606) can be
Different.
If performing noise measurement during the active state of communication, then can be by different from each other
Time gap (temporary distance) place sends continuous print payload data symbol and has used
Imitate payload data symbol rather than use predetermined training symbol.
According to another embodiment, alternately or in addition, during the rest state of communication (such as,
At the communication interval not having signal of communication to be sent, or as be explained in detail with reference to Fig. 7 in advance
In definition communication frame), noise is measured.
Fig. 7 shows the frame for synchronous communication system, this communication system can include multiple can be from difference
Similar or the different PLT system that manufacturer obtains.Period (in-home is synchronized in Jia
Synchronization period) 760 align with AC line period, wherein, including when synchronizing at home
Time slot in section 760 has the appointment timing of the zero crossing relative to AC line period.When synchronizing in Jia
Section 760 includes synchronizing signal 762, and this synchronizing signal 762 includes for being distributed by time domain unit 764
Give the PLT system or the information of modem participated in.Useful correlation function detects at receiver side
Synchronizing signal 762, and, synchronizing signal 762 is not necessarily by corresponding PLT modem
Concrete demodulation at receiver unit and error correction path.Synchronizing signal 762 can include that several are another
Outer sub-gap 771-778 for system organization.Not every sub-gap 771-778 is all used.
Such as, r-sync field 774 it is rarely employed.According to embodiment, r-sync field 774 is used for making an uproar
Sound measurement, and alternatively or additionally noise measurement with broadcast singal is entered between external communication period
The detection entered.The system of each participation relies on the person of being not engaged in and uses r-sync field 774.If
It is used, and the most all systems notice this fact, and relies on and do not use r-sync field 774
And cancel last noise measurement.
Fig. 8 A shows operation as mentioned above and can include that two or more communicate as above
The flow chart of the simplification of the method for the communication system of equipment.At receiver unit, the communication received
The signal power of signal is determined (802).At data transmitter unit, in response to determined by signal merit
Rate, sends gain and is adjusted (804).Then, during communication signal transmissions, for including noise
Frequency band, receiver frequency range is scanned (806) at receiver unit.
According to embodiment shown in the fig. 8b, the signal power of the signal of communication received is determined
(812), and if signal power exceed predetermined threshold, then gain control signal is on transport channels
It is generated and sends (814).At data transmitter unit, send gain response in gain control signal
It is adjusted (816).Then, during communication signal transmissions, for including the frequency band of noise, receive
Unit frequency scope is scanned (818) at receiver unit.
Data transmitter unit and receiver unit can be incorporated in identical communication equipment, maybe can be assigned
To two different communication equipments, wherein, gain control signal is by from including the first of receiver unit
Communication equipment is sent to include the second communication equipment of data transmitter unit.
According to embodiment, send gain and be adjusted so that the letter of the signal of communication at receiver unit
The detection of number power sub-broadcast signal, these broadcast singals can be by the nothing being arranged near communication system
Line electricity receiver receives.Such as, send gain can be adjusted so that receiver unit just can be examined
Survey radio signals (such as, the short-wave radio broadcast entering into main line with at least-95dBm
Signal) existence.
Send after gain adjusting, noise measurement can be performed during communicating, i.e. with to the letter that communicates
Number transmission carry out simultaneously.Noise measurement can include to exist broadcast singal detection and to broadcast
The detection of the frequency band of signal correction connection.When i.e. box lunch fading channel is the lowest, receiver gain also can be set
Put and be low enough to insure that the enough sensitivity for noise measurement, such as, even if during communicating also
Detection signal level is the low signal of-95dBm.Need not with the quiet time suspending communication.Separately
Outward, after the actual appearance of receivable radio signals, broadcast singal can be detected in time.
According to embodiment, reception period while to signal of communication, for including higher than predetermined noise
The frequency band of the noise of level, receiver unit scanning radio frequency range.When receiver unit is in institute
In the presence of broadcast singal being detected in the signal received, receiver unit can generate shared by mark
The notching control signal of frequency band.This notching control signal may be sent to that Notch Control Unit, this trap
Control unit controls the notch filter unit in data transmitter unit and/or converter unit.
According to embodiment, before sending the signal of communication including being suitable to the predetermined training symbol that channel is estimated
During leading code, receiver frequency range is scanned.According to embodiment, continuous print training symbol is by with that
This different time gap sends.
After radio broadcast service has been previously identified as no longer can receiving, trap still can be in pre-timing
Section (such as, at least 180 seconds) interior holding activity.Except for the detection to radio signals
In addition, if PLT modem can be assumed that not available radio broadcast service and can use phase
Answer frequency, then must check the potential weight to trap frequency in the case of not using trap frequency
With so that the most measured process of radio broadcast service is disturbed.
Therefore, according to further embodiment, the method may also include, and is sent not having signal of communication
Communication interval, check whether noise level in notch band drops to the second predetermined threshold
Hereinafter, this second predetermined threshold can equal to or less than the first predetermined threshold.When making an uproar in notch band
When sound level drops under the second predetermined threshold, can disable and the frequency in notch band scope is divided
The suppression of amount so that these frequency bands can be re-used for the communication in communication system.
According to the embodiment shown in Fig. 8 C, including being suitable to predetermined training symbol that channel estimates
Signal of communication is sent to the second communication equipment, wherein, continuous print training symbol from the first communication equipment
(822) are sent at time gap different from each other.At the second communication equipment and to predetermined instruction
Practice reception period while symbol, for including the notch band of the noise higher than predetermined noise level,
Receiver frequency range is scanned, and this predetermined noise level is by (824) given by the specification of communication system.
If when when payload data is sent to the second communication equipment from the first communication equipment
Perform noise measurement during period, then can also use in the way of identical with predetermined training symbol
Effect payload data symbol, i.e. continuous print payload data symbol is by time gap different from each other
Place sends.Therefore, at the second communication equipment and while to payload data symbol, the phase is received
Between, for including the notch band of the noise higher than predetermined noise level, receiver frequency range is swept
Retouching, this predetermined noise level is by (824) given by the specification of communication system.
Fig. 9 relate to the use of difference between continuous known symbol or signal content in signal of communication away from
From communication system 700.First communication system 701 can send signal of communication.Signal of communication includes
Prearranged signals content, the form of these prearranged signals contents and outward appearance are that the second communication equipment 701 is known
's.For example, prearranged signals symbol can be adapted for the training symbol 606 that channel is estimated.According to
Shown embodiment, the first communication equipment 701 can at time gap different from each other the company of transmission
Continuous training symbol 606.About the timing of training symbol, herein with reference to Fig. 6 and relevant description.
Second communication equipment 702 is able to receive that signal of communication, further, it is possible to same to signal of communication
Time reception period for include the noise higher than predetermined noise level notch band scanning radio frequency
Rate scope, this predetermined noise level, by given by the specification of communication system 700, wherein, is sending letter
Known predetermined symbol (such as, including the fragment of the training symbol 606) period of number content, receiver
Frequency range is scanned.
Communication system 700 can be wirelessly or non-wirelessly communication system, such as, and xDSL (conventional data
Subscribers' line) or DVB-C2 (DVB-cable).According to embodiment, communication system is
Based on OFDM (OFDM) or wavelet transformation modulation scheme.According to another embodiment,
Communication system 700 is the system utilizing distribution wire to carry out data communication.Such as, communication system 700
It is power line communication (PLC), trunk communication, electric lines of force telecommunications (PLT), broadband power line (BPL)
Electric power band or utilize be added to respectively 50Hz or 60Hz alternating current electric lines of force on brewed load
Electric lines of force networking (PLN) of ripple.Transmission line 705 represents two communication equipments of wired communication system
Between transmission channel.Communication equipment can be transmitter apparatus and receiver device, or two
Bi-directional device (modem).
Second communication equipment 702 at least includes the receiver unit 720 being connected to transmission line 705.Connect
Receipts machine unit 720 can include for being amplified the signal of communication 721 received on transmission line 705
Receive amplifying unit 722, for amplify signal of communication 723 sample ADC (simulation
To digital converter) 724, and be used for being digitally processed the signal of communication 725 that (decoding) has sampled
Decoder element 726.Receiver unit 720 can include or may not include for avoiding amplifier mistake
Carry or the saturated AGC (automatic growth control) of ADC 724.ADC 724 can be high dynamic
Scope transducer, such as, 16 ADC.
First communication equipment 701 the most also includes the data transmitter unit 710 being connected to transmission line 705.
Data transmitter unit 710 is configured on transmission line 705 send signal of communication.Data transmitter unit 710
Comprising the steps that transmission coding unit 712, it is according to modulation scheme (such as, OFDM (orthogonal frequency
Multiplexing) modulation scheme) digitally modulate (coding) data stream 711；For by encoded data
Circulation changes the DAC (digital analog converter) 714 of analogue signal into；And amplify analogue communication letter
Number to generate the transmission amplifier unit 716 of signal of communication via transmission line 705 transmission.Amplifier
The gain of unit 716 can be adjustable, it is also possible to is nonadjustable.
Each communication equipment 701,702 can include processing unit 750, and this processing unit 750 is used for
Process via transmission line 105, further via data line 759 or from the data of sensor reception,
Further, this processing unit 750 will be via transmission line 705, further via data biography for preparation
Defeated line 759 or the data sent to actuator.By way of example, communication equipment 701,702 can be
With the PLT equipment of the identical interface to transmission line 705, in this case, it is provided by main line.
The transmitter 710 of both communication equipments 701,702, receiver 720 and processing unit 750
Can be equal to separately from each other, it is also possible to be not equal to.Receiver unit 720 can include decoder
Unit, this decoder element includes converter unit, and this converter unit receives the signal of communication 725 sampled
And perform FFT for obtaining the range value including multiple frequencies in the communication signal.Frequency and Amplitude
Value represents that the frequency spectrum to the signal of communication 725 sampled describes.
Based on frequency spectrum, demodulator unit can be such as by utilizing qam demodulator to perform sampling
The demodulation of digital signal, in order to obtain the baseband representation of the signal of communication 721 received.Error correction
Unit can perform error correction method to the baseband representation of the signal of communication received.Baseband representation can be forwarded
To processing unit 750.Noise detection unit 726b is such as included in reception based on this frequency spectrum measurement
Noise in signal of communication.When the entrance of broadcast singal being detected, noise detection unit 726b is raw
Become notching control signal 791.Notching control signal 791 includes about radio signals being detected
The information of the frequency at place.
Data transmitter unit 710 can include that (this error correction unit inserts generation according to error correction scheme to error correction unit
Code redundancy) and modulator unit that obtained data stream is modulated, wherein, this manipulator list
The available multiple carrier frequencies of unit, such as, QAM.Can use and by what Notch Control Unit provided be
Number to weight to each modulated carrier signal.Known by the carrier wave of trap may this stage
It is suppressed.All carrier waves not omitted can be sued for peace by converter unit, and, application IFFT with
Time domain generates signal.It addition, this signal can be by trap wave unit filter filtering to overcome weak side to circulate
Suppression, this trap wave unit wave filter also can be by Notch Control Unit control.Notch Control Unit can receive
Notching control signal 791, this notching control signal such as can be surveyed by the noise in receiver unit 720
Amount unit 726b generates.
As already described above, if noise measurement performed in a period, then can also pass through
Send continuous print payload data symbol at time gap different from each other, use payload number
According to symbol, and non-predetermined training symbol.
The feature of communication system 700 can further with as about the embodiment described by figure before
Feature is combined, and is not exclusively used in those elements of adaptive power management.
Claims (12)
1. the method operating communication system, including
At receiver unit (120,420) place, determine via transmission channel (105,405,
505) signal power of the signal of communication received；And
At data transmitter unit (110,510) place, in response to determined by signal power and adjust
The signal power of whole described signal of communication so that signal of communication level and predetermined noise level
Ratio is equal to or less than the dynamic range of analog-digital converter (124), and this simulation numeral turns
Parallel operation (124) is included in described receiver unit (120) and is configured to change institute
State signal of communication；And
Receive at described receiver unit (120,420) place and while to signal of communication
Period, for the notch band of the noise included higher than described predetermined noise level, scanning connects
Receive unit frequency scope.
Method the most according to claim 1, also includes
If described signal power exceedes predetermined threshold, then via described transmission channel (105,
405,505) gain control signal is sent to from described receiver unit (120,420)
Described data transmitter unit (110,510), wherein
In response to described gain control signal, described signal power is adjusted.
Method the most according to claim 1, wherein
To the signal of communication lead code including being suitable to predetermined training symbol that channel is estimated
During transmission, described receiver frequency range is scanned.
Method the most according to claim 2, wherein
To the signal of communication lead code including being suitable to predetermined training symbol that channel is estimated
During transmission, described receiver frequency range is scanned.
Method the most according to claim 3, wherein
Continuous print training symbol (606) is sent with time gap different from each other.
6., according to the method described in any one in claim 1 to 5, also include
At the communication interval not having signal of communication to be sent, examine in by the frequency band of trap
Look into whether noise level drops under the second predetermined threshold, and
When by the noise level in the frequency band of trap drop to described second predetermined threshold it
Time lower, stop the suppression to the frequency component in the range of notch band.
7., according to the method described in any one in claim 1 to 5, also include
At described receiver unit, in the synchronization period not having signal of communication to be sent
(714) period, making an uproar higher than predetermined noise level is included in receiver frequency range interscan
The notch band of sound.
8. a method for operation communication system (700), including
To include being suitable to the signal of communication of the predetermined training symbol (606) that channel is estimated from the
One communication equipment (701) is sent to the second communication equipment (702)；
Described second communication equipment (702) place and while to signal of communication receive the phase
Between, carry out scanning radio frequency for the notch band including the noise higher than predetermined noise level
Rate scope；Wherein
During the transmission to described predetermined training symbol (606), described receiver frequency
Scope is scanned, and
Continuous print training symbol (606) is sent at time gap different from each other.
Method the most according to claim 8, wherein
It is positioned at first of each training symbol (606) and includes the protection interval of signal section
(604) it is provided in different lengths.
Method the most according to claim 8 or claim 9, wherein
The gap (610) of different length is arranged between continuous print training symbol.
11. 1 kinds of communication systems, including
First communication equipment (701), this first communication equipment (701) is configured to send
Including the signal of communication of the predetermined training symbol (606) being suitable to channel estimation, wherein, continuously
Training symbol (606) sent at time gap different from each other；And
Second communication equipment (702), this second communication equipment is configured to receive described communication
Signal, and it is configured to reception period while to described signal of communication, for including
Carrying out scanning radio frequency range higher than the notch band of the noise of predetermined noise level, this is pre-
Determine noise level by given by the specification of described communication system (700), wherein, to described
During the transmission of training symbol (606), described receiver frequency range is scanned.
The method of 12. 1 kinds of operations communication system (700), including
To include that the signal of communication being suitable to the payload data symbol that channel is estimated is from first
Communication equipment (701) is sent to the second communication equipment (702)；
The second communication equipment (702) place and while to described signal of communication receive the phase
Between, for including the notch band of the noise higher than predetermined noise level, scanning radio frequency
Rate scope；Wherein
During the transmission to described payload data symbol, described receiver frequency range
Scanned, and
Continuous print payload data symbol is sent at time gap different from each other.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP09009295.8 | 2009-07-16 | ||
| EP09009295 | 2009-07-16 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201080031044.0A Division CN102474304B (en) | 2009-07-16 | 2010-07-01 | Communications system using adaptive frequency notching |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104320159A CN104320159A (en) | 2015-01-28 |
| CN104320159B true CN104320159B (en) | 2017-01-04 |
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ID=
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