CN100542061C - Wireless Telecom Equipment - Google Patents
Wireless Telecom Equipment Download PDFInfo
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- CN100542061C CN100542061C CNB2004800015425A CN200480001542A CN100542061C CN 100542061 C CN100542061 C CN 100542061C CN B2004800015425 A CNB2004800015425 A CN B2004800015425A CN 200480001542 A CN200480001542 A CN 200480001542A CN 100542061 C CN100542061 C CN 100542061C
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Abstract
The present invention relates to Wireless Telecom Equipment, a kind of communication equipment of operating under the backscatter system that relates to the QPSK modulated process wherein is provided.Described equipment comprises: be used to obtain first channel of first reflected wave, described first reflected wave the ripple path not via the situation of any phase shifter under direct reflection input radio wave and obtaining; Be used to obtain the second channel of second reflected wave, described second reflected wave is by having the phase shift of pi/2 with respect to the phase place of first reflected wave via the two-way ripple path of first phase shifter; Be used to obtain the 3rd channel of the 3rd reflected wave, described the 3rd reflected wave is by having the phase shift of π with respect to the phase place of first reflected wave via the two-way ripple path of first and second phase shifters; And the 4th channel that is used to obtain the 4th reflected wave, described the 4th reflected wave is by having the phase shift of 3 pi/2s with respect to the phase place of first reflected wave via the two-way ripple path of first to the 3rd phase shifter.
Description
[technical field]
The present invention relates to a kind of Wireless Telecom Equipment of under the radio communications system that uses the microwave on the particular band, operating.More specifically, the present invention relates to a kind of Wireless Telecom Equipment of communicating with low power level with the equipment that is in the near position that connects of being used for.
In addition, the present invention relates to a kind of Wireless Telecom Equipment, this equipment allow based on antenna terminal operation, carry out data communication, the absorption and the reflection of the radio wave that wherein said backscatter system utilization is received by using backscatter system via short relatively distance.Specifically, the present invention relates to a kind of being used for to be higher than in the past bit rate, to increase the Wireless Telecom Equipment of the transfer rate of backscatter type data communication via modulated process.
[background technology]
RFID (radio frequency identification) is the exemplary means of the available radio communication in this locality.RFID realizes that as the system that mainly is made up of label and reader described reader is read the information of each label in contactless mode.RFID is also referred to as ID system or data carrier system as the recognition system of using radio frequency (radio wave).Communication between label and the reader/writer can be subjected to the influence of various mode, and these modes comprise electromagnetic coupled, electromagnetic induction and radio frequency communication (referring to non-patent literature 1).
The RFID label is the device that comprises special mark information.In the operation, during radio wave on receiving characteristic frequency, described label just generates radio wave with the modulating frequency corresponding to identification information.Read the reader of RFID label and can determine its identity based on its frequency of oscillation.Thereby, allow the article of carrying RFID label or the owner of article to be identified by the specific ID that writes label based on the system of RFID.At present, RFID is applied to a lot of systems, such as be used for administrative staff pass in and out controlled room comings and goings enter/withdraw from management system, the article mark system of use in distribution industry is used for the bill settlement system of cafeteria and is used for CD and the burglary-resisting system of the retail shop of software product.
For instance, can be combined as a kind of small-sized wireless identification devices (referring to patent documentation 1) to the IC chip with data transmission and reception and data storage capacities, the power supply that is used for chip for driving and antenna with the form of packing.With regard to the use of this wireless identification devices, the various data item on product and the article are transferred to the receiving system of IC chip via antenna.Can be in the memory of chip the storage that is sent, and can with its via antenna wireless output to the outside.Can make the existence of the product of carries chips or article like this and the position is tracked and identification.
Fig. 9 shows the typical structure of conventional rfid system.The RFID label that reference marker 101 expressions are made of label chip 102 and antenna 103.Described antenna 103 for example can be a half-wave doublet antenna.Described label chip 102 is made up of modulating part 110, rectification/demodulation parts 112 and memory unit 113.
Send radio wave f from label reader 100
0Before being imported into rectification/modulating part 110, receive by antenna 103.Described parts 110 are the radio wave f that is received
0Rectification is a direct current, so that trigger demodulation function.Thus, according to label 101 radio wave is identified as read output signal.By radio wave f
0Reception and the power that generates also is fed to memory unit 113 and modulating part 110.
Described memory unit 113 reads and before is stored in inner id information, and the information that retrieves is sent to modulating part 110 as dateout.The modulating part of being made up of diode switch 111 110 repeatedly carries out the switch motion of turn-on and turn-off according to the bitmap of dateout.More particularly, when data were " 1 ", diode switch 111 was switched on so that come the termination antenna with antenna impedance (for example, with 50 ohm).At this point, the radio wave that comes from label reader 100 is absorbed.When data were " 0 ", diode switch 111 was turned off (that is, being opened) so that come the termination antenna with open mode.At this point, the radio wave that comes from label reader 100 is reflected and is sent back to the place that it sends.Input radio wave reflection-absorption mode is according to representing data such as the sort of well-known mode of backscatter system.By this way, label 101 can send its internal information under the situation of consumed power not.
Described label reader 100 is by constituting such as host apparatus 106, the label reader module 104 of PDA and the antenna 105 that links to each other with label reader module 104.
Described host apparatus 106 sends to communication control unit 119 to sense command from label 101 via host interface parts 120.One receives the sense command that comes from host interface parts 120, and communication control unit 119 is just edited dateout according to predetermined way, filters the data of having edited, and the data of having filtered are sent to ASK modulating part 117 as baseband signal.The frequency f of ASK modulating part 117 frequency of utilization synthesizers 116
0Carry out ASK (amplitude shift keying) modulation.
Described frequency synthesizer 116 setpoint frequency under the control of communication control unit 119.Usually, determine the transmission frequency of RF label by jumping, standing wave and multichannel so that minimizing is come out in the signal of label are disturbed.Jump commands is also provided by described communication control unit 119.The output signal of carrying out the ASK modulation was transferred to circulator 114 before sending to label 101 from antenna 105.
Described label 101 is by via the reflex of backscattering (as mentioned above), come inverse signal to be same as from the signal frequency of label reader 100.The signal that returns receives and is input to blender 115 by the antenna 105 of label reader 100.Because described blender 115 is allowed the local frequency f that is same as output signal
0, so the signal that label 101 is modulated appears passing through at the output of blender 115.118 demodulation of demodulation parts are exported the data that form by 1 and 0 of signal, and data are transferred to communication control unit 119.The described data of described communication control unit 119 decodings, so that obtain the ID data, described ID data are stored in the memory unit 113 of label 101 inside, and by host interface parts 120 described ID data are transferred to host apparatus 106.
In above-mentioned the setting, described label reader 100 can read information from label 101 inside.Described label reader 100 common double as label registers can be used for host apparatus 106 data designated are write in the memory unit 113 in the label 101.
Usually, above-mentioned this backscatter type wireless communication system label is usually by using the RFID label to be mainly used in article and personnel's sign and identification.This is because the communication range of communication system has been limited in short relatively distance.
Simultaneously, as long as communication distance is limited, the backscatter type radio communication has the potential that wireless transfer channel is provided with very rudimentary power consumption so.Confirmed to have occurred the IC chip that is used to support memory function by means of improved group technology recent years, and memory capacity has also increased several times.This development has not only caused the needs of communicating by letter via short-range relatively sign and identifying information, but also has caused the needs of using based on the general data transmission of backscatter type communication.
Yet conventional backscatter type communication system fails to provide general application required high data rate.This is because they are based on ASK (amplitude shift keying) or BPSK (binary phase shift keying) principle, and promptly the modulation method of relative low bit rate is operated.
[patent documentation 1]
Flat 6-123773 Japan is publication
[non-patent literature 1]
" RFID Handbook:the Principle and Applications of NoncontactIC Cards " (by Klaus Finkenzeller, be translated as Japanese and publish) by Nikkan Kogyo Shimbun Co., Ltd by Soft Kogaku Kenkyusho Co., Ltd.
[summary of the invention]
[the present invention is with the problem that solves]
Thus, the purpose of this invention is to provide a kind of Wireless Telecom Equipment, useful is, this equipment by antenna terminal operation and based on utilizing the absorption that received radio wave and the backscatter system of reflection to come to carry out data communication via relative short distance.
Another object of the present invention is to provide a kind of is used for to be higher than in the past bit rate, to increase the Wireless Telecom Equipment of the transfer rate of backscatter type data communication via modulated process.
[being used to solve the means of described problem]
In implementing process of the present invention and according to a first aspect of the present invention, a kind of Wireless Telecom Equipment is provided, be used for using the input radio-wave reflection to carry out data communication based on backscatter system, described Wireless Telecom Equipment comprises data unit, comprising: be used to receive and come from data and pass on the antenna of input radio wave of destination; And n channel, wherein k channel provides phase difference (k-1) λ/2 for the unidirectional ripple by wherein
N-1, 1≤k≤n wherein; And the reflection configuration apparatus for converting, be used for selecting any one channel to form reflected wave with n out of phase according to dateout; Wherein said data unit uses the phase difference pattern with respect to the reflected wave of input radio wave to form dateout.
Preferably, the Wireless Telecom Equipment of said structure can also comprise first to (n-1) individual phase shifter, all provides phase difference λ/2 for the unidirectional ripple by wherein
N+1, described phase shifter is connected in series to described antenna.Preferably, a described n channel can comprise first channel that is used to obtain first reflected wave, described first reflected wave be the ripple path not by the situation of any phase shifter under directly reflection input radio wave obtain, and k the channel that is used to obtain k reflected wave, described k reflected wave has (k-1) pi/2 via the two-way phase of wave that passes through for the first reflected wave phase place between first phase shifter and (k-1) phase shifter
N-1Phase shift, 1≤k≤n wherein.
Preferably, described reflection configuration apparatus for converting is by being divided into dateout per 2
N-1The increment of bit and by according to 2
N-10 and 1 combination in the bit and the channel selected to distribute phase place to reflected wave carries out 2 with this
nPhase place PSK modulation.
Preferably, the Wireless Telecom Equipment of said structure also comprises first to the n pip, and it is between the antenna and first phase shifter, between (k-1) phase shifter and k the phase shifter, wherein 2≤k≤n-1, and the downstream that is positioned at (n-1) phase shifter.Each pip for example can or use open circuit termination to form by ground connection.
Preferably, described reflection configuration apparatus for converting is by being divided into dateout per 2
N-1The increment of individual bit and by according to 2
N-10 and 1 combination toggle reflections point distributes phase place to reflected wave in the bit, carries out 2 with this
nPhase place PSK modulation.
Wherein, when implementing like that of as above outlining is of the present invention, use backscatter system to carry out wireless data transmission, described backscatter system is carried out QPSK modulation, wherein n=2.
In according to another preferred structure of the present invention, described Wireless Telecom Equipment can also comprise first to the 3rd phase shifter, and each phase shifter is for providing the phase difference of λ/8 by unidirectional ripple wherein, and described phase shifter is connected in series to antenna; Wherein n channel can comprise: be used to obtain first channel of first reflected wave, described first reflected wave by the ripple path not by the situation of any phase shifter under directly the described input radio wave of reflection obtain; Be used to obtain the second channel of second reflected wave, described second reflected wave is by having the phase shift of pi/2 with respect to the phase place of described first reflected wave via the two-way ripple path of described first phase shifter; Be used to obtain the 3rd channel of the 3rd reflected wave, described the 3rd reflected wave by via described first and the two-way ripple path of described second phase shifter have the phase shift of π with respect to the phase place of described first reflected wave; And the 4th channel that is used to obtain the 4th reflected wave, described the 4th reflected wave is by having the phase shift of 3 pi/2s with respect to the phase place of described first reflected wave via the two-way ripple path of described first to the 3rd phase shifter.
For example, be " 00 " if be divided into the data of dibit, can select first channel so.If data are " 01 ", can select second channel to obtain reflected wave so, described reflected wave phase place of reality when being " 00 " when data has the phase places of displacement 90 degree.If data are " 10 ", can select the 3rd channel to obtain reflected wave so, described reflected wave phase place of reality when being " 00 " when data has the phase places of displacement 180 degree.If data are " 11 ", can select the 4th channel to obtain reflected wave so, described reflected wave phase place of reality when being " 00 " when data has the phase places of displacement 270 degree.By this way, can generate four reflected waves, described reflected wave according to the various combination of two bits of data, have four different phase places of 90 degree that are separated from each other.The method provides reflected wave by the QPSK modulation.
Preferably, described reflection configuration apparatus for converting can use the first and the 3rd channel to carry out the PSK modulation individually.
Except that data transmission applications, when the general RFID that the present invention is used for do not provide power supply uses, also very effective according to the method for the heterogeneous modulating wave of generation of the present invention.For instance, described Wireless Telecom Equipment also comprises the Data Receiving parts, described Data Receiving parts are by the filter of the input radio wave that is used to allow antenna to receive by predetermined frequency band, and are made of the Data Receiving parts that comprise demodulation component, so that form signal; Wherein said data unit and Data Receiving parts can come by switch alternately according to whether transmitting dateout.Adopt this structure, can be the input radio wave that comes from antenna minimum to lose, to be input to demodulation component via switching device and band pass filter such as the radio frequency switch.
According to a second aspect of the invention, a kind of Wireless Telecom Equipment is provided, be used for carrying out data communication based on the backscatter system that uses the input radio-wave reflection, described Wireless Telecom Equipment comprises data unit, and described data unit comprises: be used to receive and come from data and pass on the antenna of input radio wave of destination; First reflected channel that constitutes by the first radio frequency switch; Second reflected channel that constitutes by the phasing device that provides λ/8 phase differences and the second radio frequency switch; Be used for dateout is converted to from series form the serial conversion equipment of parallel signal; And synthetic/distribution apparatus, be used for the input radio wave from described antenna being distributed to reflected channel and being used for the synthetic output that comes from described reflected channel; The wherein activation of each described radio frequency switch and do not activate that two data item being to use formation to carry out the serial data converted control is so that described data unit uses reflected wave to form dateout with respect to the phase difference pattern of described input radio wave.
When the Wireless Telecom Equipment that uses according to second aspect present invention, two radio frequency switches are switched on and turn-off, so that make a radio frequency switch that is associated with the binary phase modulator have the reflected signal of λ/8 phase shifts with respect to the phase place generation of another reflected signal of another radio frequency switch generation.Thus, described equipment generates dateout by four phase PSK modulation based on from two data item of serial conversion for parallel form under switch control.
Adopt said structure, first reflected channel that is made of the first radio frequency switch plays the BPSK modulator, serves as another BPSK modulator by second reflected channel that the binary phase modulator and the second radio frequency switch constitute.Latter BPSK modulator with binary phase modulating device provides the phase delay of λ/8 for unidirectional ripple path, and the phase transformation of λ/4 is provided for two-way ripple path.Thereby latter BPSK modulator is carried out the BPSK modulation on the axle that has 90 degree phase differences for the former BPSK modulator.This structure is equivalent to carry out the structure of QPSK modulation.This is because first reflected channel is carried out the BPSK modulation on the I axle, and second reflected channel is carried out the BPSK modulation on the Q axle.In this case, described synthesizing/distribution apparatus is used for the radio wave that is received is divided into two branches and the synthetic part that is divided.
According to described mode, the input radio wave that comes from antenna was divided into two carrier waves by synthetic/distribution apparatus carried out the QPSK modulation by first and second reflected channel before.Tiao Zhi reflected signal passed through synthetic/distribution apparatus transmission before being sent from antenna once more thus.
Described serial conversion equipment is parallel form to dateout from serial conversion, promptly is converted to the parallel signal of I and Q.
[effect of the present invention]
According to the present invention, as mentioned above, provide a kind of Wireless Telecom Equipment, described equipment comes communication data based on the absorption of the use radio wave that receives and the backscatter system of reflection via relative short distance by the operation of antenna terminal.
The invention provides a kind of Wireless Telecom Equipment, be used for coming communication data with the transfer rate that is higher than in the past based on backscatter system by means of modulation method (such as the QPSK modulation) according to the bit rate that improves.
The present invention also provides a kind of wireless communication system and Wireless Telecom Equipment, is used for wirelessly the view data that comes from such as the mancarried device of digital camera or portable phone is transferred to PC, TV, printer or the like with minimum power consumption.
The present invention also provides a kind of wireless communication system and a kind of Wireless Telecom Equipment, is used to utilize minimum power consumption that data are transferred to from a device and is positioned at separately short-range relatively another device.
Thus, the invention provides such structure, compare with the WLAN (wireless local area network) setting, this structure is used to make the mobile device can transmit image data, simultaneously realize that greatly power consumption reduces.This structure of the present invention can greatly prolong the battery life of mobile device.
In addition, the present invention is easy to realize make the data transmitter of wireless transport module as mobile device with the cost that is lower than the WLAN (wireless local area network) alternative.This wireless transport module in the mobile device is not thought the wireless site based on Japanese radio law.This means does not need to address the chare of asking and securing permission from authorities, all qualitys certificate in this way of described permission.
When reading the following description and drawings, other purposes of the present invention, feature and advantage become more obvious.
[description of drawings]
[Fig. 1]
Fig. 1 is the schematic diagram that the hardware configuration of specific implementation Wireless Telecom Equipment 300 of the present invention is shown;
[Fig. 2]
Fig. 2 is the schematic diagram that shows the typical structure of the Wireless Telecom Equipment of operating under the backscatter system that adopts the QPSK modulation;
[Fig. 3]
Fig. 3 is the schematic diagram that is described in the typical structure of the Wireless Telecom Equipment of operation under the backscatter system that adopts eight-phase PSK modulation;
[Fig. 4]
Fig. 4 is the schematic diagram that shows another structure of the Wireless Telecom Equipment that adopts the QPSK modulation;
[Fig. 5]
Fig. 5 illustrates the schematic diagram of reception from the wireless communication device hardware structure of the Wireless Telecom Equipment data of Fig. 2 or Fig. 4;
[Fig. 6]
Fig. 6 is when the Wireless Telecom Equipment 300 of the Fig. 2 that serves as image transmission or Fig. 4 carries out RFDC with the Wireless Telecom Equipment 400 that serves as Fig. 5 of image display device, the control sequence chart of the typical control sequence that general introduction is actual;
[Fig. 7]
The schematic diagram of the typical structure of the wireless transport module that provides as a kind of adapter type module is provided Fig. 7;
[Fig. 8]
Fig. 8 is a schematic diagram of describing the typical structure of another wireless transport module 308 that uses with the Wireless Telecom Equipment that adopts the QPSK modulation; And
[Fig. 9]
Fig. 9 is the schematic diagram that shows the typical structure of conventional rfid system.
[reference marker explanation]
300: Wireless Telecom Equipment
302,602... camera parts
303, the 603... Signal Processing Element
304,604... memory card interface parts
305... operation/display unit
306, the 606...USB interface unit
307, the 607... storage card
308... wireless communication module
309, the 609... antenna
310,311,323,324,325... radio frequency switch
312... band pass filter
313...ASK detection part
320,321, the 322... phase shifter
330,332,334... radio frequency switch
331,333, the 335... phase shifter
400... wireless receiving module
401... antenna
402... circulator
403... receiving-member
404... orthogonal detection parts
405...AGC amplifier
406... transmit block
407... power amplifier
408... blender
409... frequency synthesizer
410... communication control unit
411... host interface parts
412... host apparatus
901... antenna
902... it is synthetic/distributed elements
903... radio frequency switch
904... λ/8 phase shifters
905... radio frequency switch
906... serial transducer
[embodiment]
Describe the preferred embodiments of the present invention in detail now with reference to accompanying drawing.
The present invention mainly provides a kind of radio communication setting, is used to utilize minimum power consumption that data are transferred to basically from a device and is positioned at separately short-range relatively another device.According to the present invention, use is carried out wireless data transmission by the reflected wave of the backscatter system acquisition of RFID.Rfid system is widely adopted already as the wireless communication means of the application that only can be used for strict location.
The system that described rfid system is made up of label and reader, and it makes reader read information in contactless mode from label inside.Described RFID label is the device that comprises unique identification information.When receiving radio wave with characteristic frequency, described label generates radio wave with the modulating frequency of the identification information preserved corresponding to inside.The frequency that described reader identification generates thus by the RFID label.Described label and reader/writer use the mode such as electromagnetic coupled, electromagnetic induction or radio frequency communication to communicate with one another.The present invention relates to the radio frequency communication method, this method is used the microwave on the 2.4 gigahertz (GHZ) base band for example.
Fig. 1 is the schematic diagram that the hardware configuration of specific implementation Wireless Telecom Equipment of the present invention is shown.This Wireless Telecom Equipment 300 can be digital camera, be equipped with the portable phone of camera or be similar to transmit image data simultaneously mainly based on the battery-operated equipment (not shown).
As digital camera, described Wireless Telecom Equipment 300 for example constitutes by camera parts 302, Signal Processing Element 303, memory card interface parts 304, operation/display unit 305 and USB interface parts 306.
Described Signal Processing Element 303 is converted to JPEG (JPEG (joint photographic experts group)) or other suitable form to the view data that comes from camera parts 302.The view data of conversion is thus put into external memory card 307 via memory card interface 304 so that storage.
Described operation/display unit 305 provides image to show and allows to make necessary setting.Described USB (USB) interface unit 306 is used for the view data from camera is transferred to PC via USB interface.
As its wireless transport module 308, the Wireless Telecom Equipment 300 of this embodiment uses the RFID label of radio frequency type.
Described wireless transport module 308 is made up of antenna 309, radio frequency switch 310 and 311, band pass filter 312 and ASK detection part 313.This embodiment is used as its radio frequency to 2.4 gigahertz (GHZ) bandwidth.
In comprising the data transmission procedure of image conveyer, in response to the control signal from Signal Processing Element 303, described radio frequency switch 311 is turned off, and ASK detection part 313 is converted to open mode.Wireless transport module 308 receives by the view data of Signal Processing Element 303 from storage card 307 retrievals.When receiving the view data of retrieval, another radio frequency switch 310 that described wireless transport module 308 comes conducting or shutoff to link to each other with antenna 309 according to the bitmap that receives data.For example, if described data are " 1 ", radio frequency switch 310 is switched on so; If data are " 0 ", switch 310 is turned off so.
When described radio frequency switch 310 is switched on, antenna 309 is short-circuit ground so, is absorbed thus so that use from passing on the radio wave of destination (waiting a moment discussion), as shown in the figure.When turn-offing described radio frequency switch 310, described antenna 309 is opened, and passes on the radio wave of destination and is reflected so that come from.In response to described input radio wave, the operation of the turn-on and turn-off of radio frequency switch 310 generates reflected wave, their separately phase place 180 degree.This means: pass on the destination and can read the data-signal that is sent, such as view data by the reflected phase will that detects the input radio wave.
More particularly, when reality adopts backscatter system, view data is transmitted by the reflected wave that experience PSK (phase shift keying) modulation is obtained as the input radio wave, and wherein said input radio wave is owing to the fluctuation in the antenna load impedance that turn-on and turn-off produced of radio frequency construction of switch generates.The reflection wave signal that comes from wireless transport module 308 is equivalent to the PSK modulating wave.
Described radio frequency switch 310 is made up of GaAs IC usually, and it consumes tens μ W or lower power.Thus, above-mentioned communication means provides the wireless image transmission with low-down power consumption level.
When receiving data, come described radio frequency switch 311 of conducting and ASK detection part 313 by the control signal that comes from Signal Processing Element 303.
Described band pass filter 312 and ASK detection part 313 are used to receive come from and pass on the transmitting confirmation signal of ASK modulation of destination.If described transmission is based on unidirectional generation, promptly under the situation of not expecting to confirm, take place, do not need this two modules so.If confirmation request, so related control procedure is undertaken by Signal Processing Element 303.
Described band pass filter 312 is used to allow the input radio wave pass through on 2.4 gigahertz (GHZ) frequency bands, allows the signal component of decay pass through on any other frequency band simultaneously.In the process of confirming transmission, described ASK detection part 313 consumes 30 milliwatts or lower power.
Therefore, for the two-way communication setting that relates to affirmation, Wireless Telecom Equipment at Fig. 1 carries out adding up to 10 milliwatts or less such as the average power consumption during the transfer of data of image, and under the situation for the one-way data transmission that does not need to confirm, power consumption adds up to tens μ w.These power consumption level are starkly lower than the average power consumption of common wireless local area network (WLAN) system.
The invention still further relates to a kind of based on using the backscatter system of importing radio-wave reflection and the Wireless Telecom Equipment that carries out transfer of data with the lower power consumption rank.The present invention also can use QPSK (quaternary PSK) to implement in addition, so that carry out the modulation of reflected wave by wireless transport module 308.Coming the substituting PS K-method by the QPSK method is in order to increase the speed of transfer of data.Although the PSK modulation requires " 0 " and " 1 " is dispensed to two 180 degree phase place separately, the QPSK modulation relates to (0,0), (0,1), (1,0) and (1,1) is respectively allocated to phase place 0, pi/2, π and 3 pi/2s so that transfer of data, the described phase place pi/2 that is separated from each other.The latter's modulator approach has increased bit rate thus considerablely.Usually, 2
nPhase place PSK modulation need be data allocations to 2
nIndividual phase place, these phase places pi/2 that is separated from each other
N-1This means that in brief, bit rate is high more, the value of n is just big more.
Fig. 2 is the schematic diagram that shows the typical structure of described Wireless Telecom Equipment.Described wireless transport module 308 comprises antenna 309, radio frequency switch 311, band pass filter 312 and ASK detection part 313, and all these parts all work according to the mode identical with their appropriate section among Fig. 1.Described wireless transport module 308 also comprises the phase shifter 320,321 and 322 that is connected to antenna 309, and radio frequency switch 323,324,325 and 326 and data decoder 327.
As mentioned above, described backscatter system carries out transfer of data by the switch transition of radio frequency switch by the absorption and the reflection of alternation input radio wave.Because described radio frequency switch 323,324 and 325 is had to come switch with finite speed, so when each conversion of high speed data transfer, need in a plurality of bits, transport information.
Each described phase shifter 320,321 and 322 all can be formed by the line structure such as strip line, and described structure provides the λ (wavelength)/8 on the 2.4 gigahertz (GHZ) frequency bands displacement, is perhaps formed by the active phase shifter that can change its phase place under voltage control.Each described phase shifter 320,321 and 322 all generates the phase difference of 45 degree for unidirectional ripple path, and generates 90 degree phase differences for two-way ripple path.Because described phase shifter 320,321 and 322 is connected to antenna 309, so come turn-on and turn-off radio frequency switch 323,324,325 and 326 that different channels is provided according to various combination, the reflected wave of input radio wave can be reciprocal via these channels.This structure gives four phase differences to reflected wave.
For example, if described radio frequency switch 323 is by conducting separately, so in Fig. 2, at the described input radio wave of point " a " reflection.If described radio frequency switch 324 is switched on separately, so at the described input radio wave of point " b " reflection, the phase place with respect to the reflected wave of point " a " is shifted 90 degree but the phase place of incoming wave is because the ripple path passes phase shifter 320.If described radio frequency switch 325 is switched on separately, so at the described input radio wave of point " c " reflection, but the phase place of incoming wave is because the ripple path passes phase shifter 320 and 321 and be shifted 180 degree with respect to the phase place of the reflected wave of point " a ".If described radio frequency switch 326 is switched on separately, so at the described input radio wave of point " d " reflection, but the phase place of incoming wave is because the ripple path passes phase shifter 320,321 and 322 and be shifted 270 degree with respect to the reflected wave phase place of point " a ".That is to say, alternately conducting radio frequency switch 323,324,325 and 326 each can generate reflected wave, and their four phase places be separated from each other 90 the degree.
For transfer of data, under the control of Signal Processing Element 303, turn-off described radio frequency switch 311, and ASK detection part 313 is converted to open mode such as image conveyer.Described wireless transport module 308 is carried out the QPSK modulation by data being divided into the dibit increment, distributes phase place corresponding to dibit 0/1 combination that changes to each bit increment.
More particularly, when receiving by Signal Processing Element 303 from view data that storage card 307 reads, described wireless transport module 308 transfers to data decoder 327 to the bitmap of the data that retrieve.Described data decoder 327 is divided into the dibit increment to the data that received, if data image is thus " 00 ", so independent conducting radio frequency switch 323, if data image is " 01 ", so independent conducting radio frequency switch 324, if data image is " 11 ", the switch of conducting radio frequency so 325, if and data image is " 10 ", conducting radio frequency switch 326 so separately.
When data are " 00 ", conducting radio frequency switch 323 so separately.Order input radio wave will be reflected at point " a " like this.
When data are " 01 ", conducting radio frequency switch 324 so separately.Order input radio wave will be reflected at point " b " like this.Because its path passes phase shifter 320, so the reflected wave that described reflected wave is located with respect to point " a " has the phase shift of 90 degree.
When data are " 11 ", independent conducting radio frequency switch 325.Make described input radio wave be reflected like this at point " c ".Because its path passes phase shifter 320 and 321, so the reflected wave phase place that described reflected wave is located with respect to point " a " has the phase shift of 180 degree.
When data are " 10 ", so independent conducting radio frequency switch 326.Order input radio wave will be reflected at point " d " like this.Because its path passes phase shifter 320,321 and 322, so the reflected wave that described input radio wave is located with respect to point " a " has the phase shift of 270 degree.
By this way, can generate the reflected wave of QPSK modulation, the difference of the two bit value of described reflected wave data-driven has four different phase places that are separated from each other with 90 degree.
The wireless transport module 308 of Fig. 2 can also be carried out the PSK modulation.In this case, described radio frequency switch 324 and 326 is uncontrolled.When data were " 0 ", described radio frequency switch 323 was switched on; When data were " 1 ", radio frequency switch 325 was switched on, so that the phase place of reality is phase-shifts 180 degree of reflected wave when being " 0 " when data.That is to say that same circuit can be handled two kinds of modulation methods, i.e. QPSK and PSK.In communication period, these two kinds of methods can dynamically replace.
Will be appreciated that except that the data communications applications method of the present invention that being used to of Fig. 2 created heterogeneous modulating wave also can be effective to not provide the general RFID of power supply to use.
When receiving the input radio wave, under the control of Signal Processing Element 303, come described radio frequency switch 311 of conducting and ASK detection part 313.In addition, described radio frequency switch 323,324 and 326 is turned off, and radio frequency switch 325 is switched on separately.When adopting these to set in practice, the input signal that comes from antenna 308 is input to ASK detection part 313 with minimum losing via band pass filter 312.
Described band pass filter 312 and ASK detection part 313 are used to receive come from and pass on the transmitting confirmation signal of ASK modulation of destination.If described transmission is based on unidirectional generation, promptly under the situation that does not need to confirm, take place, do not need this two modules so.If confirmation request, so related control procedure is undertaken by Signal Processing Element 303.
In another modification, can be connected seven λ/16 phase shifters and eight radio frequency switches with the method the same with first preceding example based on the Wireless Telecom Equipment of Fig. 2 of the backscatter system that adopts the QPSK modulation.This set provides eight-phase PSK modulated structure, whereby be separated from each other eight reflected waves of 45 degree of phase place is distributed to eight interior data bit modes of from " 000 " to " 111 " scope.
Fig. 3 is the schematic diagram that is described in the typical structure of the Wireless Telecom Equipment of operation under the backscatter system that adopts eight-phase PSK modulation.The equipment of Fig. 3 comprises wireless transport module 508, described wireless transport module 508 is made up of antenna 509, radio frequency switch 511, band pass filter 512 and ASK detection part 512, and all these parts work according to the mode identical with appropriate section in Fig. 1 equipment.The Wireless Telecom Equipment of Fig. 3 also comprise seven phase shifters 521,522,523 of being connected to antenna ..., 527; Radio frequency switch 531,532,533 .., 538 and data decoder 540.
As mentioned above, described backscatter system carries out transfer of data by the switch transition of radio frequency switch by the absorption and the reflection of alternation input radio wave.Because described radio frequency switch 531,532,533 or the like is had to come switch with finite speed, so when each conversion of high speed data transfer, need in a plurality of bits, transport information.
Described phase shifter 521,522,523 ..., 527 all can form by line structure such as strip line, be used to provide λ/16 displacements on the 2.4 gigahertz (GHZ) frequency bands, perhaps form by the active phase shifter that can under voltage control, change its phase place.Described phase shifter 521,522,523 ..., in 527 each all generate the phase differences of 22.5 degree for unidirectional ripple path, and generate 45 degree phase differences for two-way ripple path.Thus according to different combinations come turn-on and turn-off radio frequency switch 531,532,533 ..., 538 can provide different channels, the reflected wave of input radio wave is reciprocal via these channels.This structure gives eight phase differences to reflected wave.
For example, if described radio frequency switch 531 in Fig. 3, is located to reflect described input radio wave at point " a " so by conducting separately.If described radio frequency switch 532 is switched on separately, locate to reflect described input radio wave at point " b " so, but the phase place of the reflected wave that the phase place of incoming wave is located with respect to point " a " because the ripple path passes phase shifter 521 is shifted 45 degree.If described radio frequency switch 533 is switched on separately, locate to reflect described input radio wave at point " c " so, but the phase place of incoming wave is because the ripple path passes phase shifter 521 and 522 and be shifted 90 degree with respect to the phase place of the reflected wave of point " a ".Equally, if radio frequency switch 538 is switched on separately, locate reflection input radio wave at point " h " so, but the phase place of the reflected wave that the phase place of incoming wave is located with respect to point " a " because the ripple path passes all seven phase shifters 521 to 527 is shifted 315 degree.That is to say, alternately conducting radio frequency switch 531,532,533 ..., in 538 each can generate reflected wave, and their eight phase places 45 degree that are separated from each other.
For transfer of data, under the control of Signal Processing Element 503, turn-off described radio frequency switch 511, and ASK detection part 513 is converted to open mode such as image conveyer.Described wireless transport module 508 is carried out eight-phase PSK modulation by data being divided into three bit increments, and the variation of making up corresponding to three bits 0/1 distributes phase place to each bit increment.
More particularly, when receiving by Signal Processing Element 503 from view data that storage card 307 reads, described wireless transport module 508 transfers to data decoder 540 to the bitmap of the data that retrieve.Described data decoder 540 is divided into three bit increments to the data that received, if data image is thus " 000 ", so independent conducting radio frequency switch 531, if data image is " 001 ", so independent conducting radio frequency switch 532, if data image is " 011 ", the switch of conducting radio frequency so 533, or the like.
When data are " 000 ", so independent conducting radio frequency switch 531.Order input radio wave will be reflected at point " a " like this.When data are " 001 ", independent conducting radio frequency switch 532.Order input radio wave will be reflected at point " b " like this.Because its path passes phase shifter 521, so the reflected wave that reflected wave is located with respect to point " a " has the phase shift of 45 degree, " a " locates at point, and data are " 000 ".
When data are " 011 ", so independent conducting radio frequency switch 533.Order input radio wave will be reflected at point " c " like this.Because its path passes phase shifter 521 and 522, so the reflected phase will that reflected wave is located with respect to point " a " has the phase shift of 90 degree, " a " locates at point, and data are " 000 ".
When data are " 010 ", so independent conducting radio frequency switch 534.Order input radio wave will be reflected at point " d " like this.Because its path passes phase shifter 521,522 and 523, so the phase place of the reflected wave that the input radio wave is located with respect to point " a " has the phase shifts of 135 degree, " a " locates at point, and data are " 000 ".Carry out inevitable switching manipulation according to same mode with radio-wave reflection.
As mentioned above, can generate the reflected wave of eight-phase PSK modulation, the difference of three bit values of described reflected wave data-driven has eight different phase places that are separated from each other with 45 degree.
The wireless transport module 508 of Fig. 3 can also be carried out the PSK modulation.In this case, except switch 531 and 534, all radio frequency switches all are uncontrolled.When data were " 0 ", described radio frequency switch 531 was switched on; When data were " 1 ", radio frequency switch 534 was switched on, so that the actual phase when being " 0 " when data is phase-shifts 180 degree of reflected wave.That is to say that same circuit can be handled two kinds of modulation methods, i.e. eight-phase QPSK and PSK.In communication period, these two kinds of methods can dynamically replace.
Will be appreciated that except that the data communications applications method of the present invention that being used to of Fig. 3 created heterogeneous modulating wave also can be effective to not provide the general RFID of power supply to use.
When receiving the input radio wave, under the control of Signal Processing Element 503, come described radio frequency switch 511 of conducting and ASK detection part 513.In addition, one of them that have only radio frequency switch 531 to 538 is switched on, and other switches turn-off.When reality adopts these to be provided with, the input signal that comes from antenna 508 is input to ASK detection part 513 with minimum losing via radio frequency switch 511 and band pass filter 512.
Described band pass filter 512 and ASK detection part 513 are used to receive come from and pass on the transmitting confirmation signal of ASK modulation of destination.If described transmission is based on unidirectional generation, promptly under the situation that does not need to confirm, take place, do not need this two modules so.If confirmation request, so related control procedure is undertaken by Signal Processing Element 503.
Fig. 4 is the schematic diagram that shows another structure of the Wireless Telecom Equipment of operating under the Wireless Telecom Equipment of the backscatter system that adopts the QPSK modulation.Although the equipment of Fig. 2 has the pip that forms by ground connection, but still provide the equipment of Fig. 4, pip forms by open circuit termination.
Each described phase shifter 331,333 and 335 all can be formed by the line structure such as strip line, and described structure provides λ/8 displacements on the 2.4 gigahertz (GHZ) frequency bands, perhaps by the active phase shifter that can change its phase place based on voltage control.For unidirectional ripple path, described phase shifter all generates the phase difference of 45 degree, and generates 90 degree phase differences for two-way ripple path.Thus, come turn-on and turn-off radio frequency switch 330,332 can provide different channels with 334 according to different combinations, the reflected wave of input radio wave is reciprocal via these channels.This structure gives four phase differences to reflected wave.
For example, if described radio frequency switch 330 is turned off, in Fig. 4, locate to reflect described input radio wave so at point " a ".If described radio frequency switch 330 is switched on, and described radio frequency switch 332 is turned off, at the described input radio wave of point " b " reflection,, the phase place of the reflected wave that the phase place of incoming wave is put with respect to " a " because the ripple path passes phase shifter 331 spends so but being shifted 90.If described radio frequency switch 330 and 332 is switched on, and radio frequency switch 334 is turned off, so at the described input radio wave of point " c " reflection, but the phase place of incoming wave is because the ripple path passes phase shifter 331 and 333 and be shifted 180 degree with respect to the phase place of the reflected wave of point " a ".If described radio frequency switch 330,332 and 334 all is switched on, so at the described input radio wave of point " d " reflection, but the phase place of incoming wave is because the ripple path passes phase shifter 331,333 and 335 and be shifted 270 degree with respect to the phase place of the reflected wave of point " a ".That is to say, according to various combination come turn-on and turn-off radio frequency switch 330,332 and 334 can generate four phase places be separated from each other 90 the degree reflected waves.
In the process that carries out image is passed on, described wireless transport module 308 is carried out the QPSK modulation by data being divided into the dibit increment, and the variation of making up corresponding to dibit 0/1 distributes phase place to each bit increment.
More particularly, when receiving by Signal Processing Element 303 from view data that storage card 307 reads, described wireless transport module 308 transfers to data decoder 336 to the bitmap of the data that retrieve.Described data decoder 336 is divided into the dibit increment to the data that received, if data image is thus " 00 ", the switch of conducting radio frequency so 330, if data image is " 01 ", the described radio frequency switch 330 of conducting and turn-off radio frequency switch 332 so, if data image is " 11 ", the switch of conducting radio frequency so 330 and 332, and shutoff radio frequency switch 334, and when data image is " 10 ", all radio frequency switches 330,332 and 334 of conducting.
When data are " 00 ", turn-off radio frequency switch 330.Order input radio wave will be reflected at point " a " like this.
When data are " 01 ", the described radio frequency switch 330 of conducting, and turn-off radio frequency switch 332.Order input radio wave will be reflected at point " b " like this.Because its path passes phase shifter 331, so the phase place of the reflected wave that reflected wave is located with respect to point " a " has the phase shifts of 90 degree, " a " locates at point, and data are " 00 ".
When data are " 11 ", the described radio frequency switch 330 of conducting and 332, and turn-off radio frequency switch 334.Order input radio wave will be reflected at point " c " like this.Because its path passes phase shifter 331 and 333, so the reflected phase will that reflected wave is located with respect to point " a " has the phase shift of 180 degree, " a " locates at point, and data are " 00 ".
When data are " 10 ", all radio frequency switches 330,332 and 334 of conducting.Order input radio wave will be reflected at point " d " like this.Because its path passes phase shifter 331,333 and 335, so the phase place of the reflected wave that the input radio wave is located with respect to point " a " has the phase shifts of 270 degree, " a " locates at point, and data are " 00 ".
As mentioned above, can generate the reflected wave of QPSK modulation, the difference of the two bit value of described reflected wave data-driven has four different phase places that are separated from each other with 90 degree.
Fig. 5 is the schematic diagram that the wireless communication device hardware structure that receives the Wireless Telecom Equipment data that come from Fig. 2 or Fig. 4 is shown.The equipment representative of Fig. 5 is used to show or export the picture reproducer of the view data that is received such as PC, television set or printer etc.
Use reflected wave to provide view data to the equipment of Fig. 5.This requires the wireless receiving module 400 unmodulated carrier waves of transmission so that produce reflected wave.Described wireless receiving module 400 is made up of antenna 401, circulator 402, receiving-member 403, transmit block 406, frequency synthesizer 409, communication control unit 410 and the host interface parts 411 of 2.4 gigahertz (GHZ) frequency bands.Described receiving-member 403 comprises orthogonal detection parts 404 and AGC (automatic gain control) amplifier 405.Described transmit block 406 comprises blender 408 and power amplifier 407.Described host interface parts 411 link to each other with host apparatus 412 such as PC, wherein via described interface the view data that is received are transferred to described host apparatus.
When described communication control unit 410 is applied to blender 408 to predetermined direct voltage, described wireless receiving module 400 transmission unmodulated carriers.The frequency of unmodulated carrier waiting for transmission is that the frequency by frequency synthesizer is determined under the control of communication control unit 410.The equipment of Fig. 5 uses 2.4 gigahertz (GHZ) frequency bands.Unmodulated carrier by blender 408 outputs is amplified to prefabricated level by power amplifier 407.The carrier wave that amplifies is sent from antenna 401 via circulator 402.
The reflected wave that comes from graphic transmission equipment 300 has the identical frequency of transmitting with aforesaid wireless receiving module 400 of carrier wave.Described reflected wave is received by antenna 401, and is input to receiving-member 403 via circulator 402.Because provide the local frequency identical, so occur carrying out PSK or the QPSK modulating wave that modulated process obtains by graphic transmission equipment 300 at the output of orthogonal detection parts 404 with transmission frequency to orthogonal detection parts 404.Because described input signal has the phase place that is different from local signal, so orthogonal detection parts 404 are exported its modulated signal according to the phase difference between input and the local signal as I axis signal and Q axis signal.
Described AGC amplifier 405 is before being sent to communication control unit 410 to gain control signal, and its I axle of importing and Q axis signal is controlled in gain best.According to I axle and Q axis signal, described communication control unit 410 is carried out PSK or QPSK demodulation, reproduces carrier wave and clock signal whereby.The correct data of reproducing are transferred to host apparatus 412 via host interface parts 411.
Confirm transfer of data if desired by image transmission 300, if the grouped data that is received is correct so, then communication control unit 410 is transferred to blender 408 to ACK (affirmation) numerical data, if perhaps the grouped data that is received is incorrect, communication control unit 410 is transferred to blender 408 to NACK (denying) numerical data so.ACK that has passed on or NACK numerical data experience ASK modulation.Whether the data that received correctly are to determine by CRC (cyclic redundancy check (CRC)) code that checking invests the image data packets that is received.
Fig. 6 shows when the Wireless Telecom Equipment 300 of the Fig. 2 that serves as image transmission or Fig. 4 carries out RFDC with the Wireless Telecom Equipment 400 that serves as Fig. 5 of image display device, actual typical control sequence.Being provided with of Fig. 6 supposed by another equipment and confirmed each transmission by an equipment.Below described control sequence will be described.
(step 1)
In image transmission, for example set up data-transmission mode by the user.
(step 2)
Equally, in image display device, for example set up the Data Receiving standby mode by the user.
(step 3)
As the image display device transmission unmodulated carrier of image conveyer destination, described thus image transmission produces reflected wave.
(step 4)
Image transmission with the unmodulated carrier that has received uses reflected wave to make data transfer request.
(step 5)
Image display device with the data transfer request that has received returns authority to send by the ASK modulation.
(step 6)
Described image display device is that unmodulated carrier is transmitted in reflected wave formation.
(step 7)
When receiving unmodulated carrier, described image transmission uses the data of reflected wave transmission packetizing.In this step, described image transmission is carried out the QPSK modulation by data being divided into the dibit increment, and the variation of making up corresponding to dibit 0/1 distributes phase place (as mentioned above) to each increment.
(step 8)
Described image display device allows the packetized data that is received carry out the QPSK demodulation, recovers initial data thus.If find that the data that received are correct, image display device returns ACK (affirmation) signal by the ASK modulation so; If find that the data that received are incorrect, so described image display device returns NACK (denying) signal.Whether described data correctly are to determine by CRC (cyclic redundancy check (CRC)) code that checking invests the received data grouping.
When transferring ACK or NACK signal, described image display device can comprise the order of issuing image transmission in same signal.For instance, described image display device can be sent to image transmission to the magic lantern request command.
According to described mode, described image display device can be controlled image transmission from remote location.If described image display device is can be sent to image display device to order from remote controller so by the television set of infrared remote controller operation, described image display device is transferred to image transmission to order again.That is to say, can use infrared remote controller to control image transmission indirectly.
Repeating step 6 to 8 then, transmitted all data up to.
In aforesaid control sequence, communicate based on two-way, confirm view data during with convenient normal transmission.As selection, can pass on from video camera or similar source under the situation of streamed data, come executive communication based on unidirectional.Adopt one-way transmission to be provided with and eliminated the needs that image display device returned ASK modulation confirmation signal.In addition, described image transmission also needn't the confirmation of receipt signal, and this has further saved power consumption.
Will be appreciated that described image transmission does not need oscillator in the process of the control sequence of execution graph 6.
In being provided with of Fig. 1, incorporate wireless transport module 308 into such as the described image transmission of digital camera.Yet this is not a limitation of the present invention.As selection, described wireless transport module can be used as dismountable adapter and provides, and it is connected to equipment of the present invention via USB (USB) or other suitable interfaces from the outside.
The typical structure of the wireless transport module that provides as the type of adapter module is be provided Fig. 7.
As shown in the figure, the image transmission among Fig. 7 comprises camera parts 602, Signal Processing Element 603, memory card interface parts 604, operation/display unit 605, USB interface parts 606 and storage card 607.These parts appropriate section 202 to 207 with the digital camera of the conventional WLAN (wireless local area network) ability shown in Fig. 6 basically are identical.
Usually, USB interface parts 606 serve as slave.Via memory card interface parts 604 after storage card 607 reads interested view data, Signal Processing Element 603 transfers to PC (usb host) to institute's data retrieved via USB interface parts 606 on USB cable.In being provided with of Fig. 7, when be connected to via USB interface from the outside during wireless transport module 601 the attached slave thereon, described USB interface parts are converted into host computer side.These settings are equivalent to the equipment shown in Fig. 1.
Described wireless transport module 601 can be the adapter that is equipped with USB connector and antenna 609, for example has the shape of the represented equipment of reference marker 620.
Described wireless transport module shown in Fig. 7 is identical with the wireless transport module 308 described among Fig. 2 or Fig. 4 basically, except it is equipped with USB interface parts 614 in addition.
When transmit image data, under the control of Signal Processing Element 303, described radio frequency switch 311 is turned off, and ASK detection part 313 is converted to open mode.Described wireless transport module 308 receives from the view data of storage card 607 retrievals via host computer side USB interface parts 606 and subordinate pusher side USB interface parts 614.By this way, can generate four reflected waves, described reflected wave has four different phase places that are separated from each other with 90 degree according to the different value of two bits of data.This system is via QPSK modulation cremasteric reflex ripple, as previous discussion.For instance, when data were " 01 ", reflected wave had the phase shift of 90 degree; When data were " 11 ", reflected wave had the phase shift of 180 degree; When data were " 10 ", reflected wave had the phase shift of 270 degree.
When receiving data, described band pass filter and ASK detection part are used for receiving coming from and pass on the ASK modulation confirmation signal of destination (as mentioned above).If described transmission is based on unidirectional generation, promptly under the situation that does not need to confirm, take place, do not need this two modules so.If confirmation request, so related control procedure is carried out by communication control unit 608.Band pass filter 612 is used to allow the input radio wave pass through on 2.4 gigahertz (GHZ) frequency bands, allows the signal component of decay pass through on any other frequency band simultaneously.
The setting of Fig. 7 allows to carry out image data transmission with low-down power consumption level as the equipment shown in Fig. 1.Along with mobile device progressively miniaturization think that to satisfy needs now the adapter type wireless transport module as the above embodiment of the present invention is especially effective.Though this embodiment uses USB interface Wireless Telecom Equipment next and such as digital camera to be connected, this is not a limitation of the present invention.But can adopt any other suitable interface.
Fig. 8 has schematically described another typical structure of the wireless transport module 308 that uses with the Wireless Telecom Equipment that adopts the QPSK modulation.
Described wireless communication module 308 among Fig. 8 comprises antenna 901, synthetic/distributed elements 902, radio frequency switch 903 and 905, is connected to λ/8 phase shifters 904 and the serial transducer 906 of radio frequency switch 905.In order to simplify and to illustrate, from Fig. 8, omitted radio frequency switch 311, band pass filter 312 and the ASK detection part 313 of receiver module in the pie graph 2.
All constitute the reflected channel that backscatter type is communicated by letter by synthetic/distributed elements 902 branches and via the channel of radio frequency switch 903 ground connection and via each channel in the channel of phase shifter 904 and radio frequency switch 905 ground connection.That is to say that described radio frequency switch 903 serves as the BPSK modulator; Similarly, phase shifter 904 and radio frequency switch 905 are operated as another BPSK modulator.
The latter's BPSK modulator has λ/8 phase delays that produced by phase shifter 904, and the phase difference of λ/4 is provided for two-way ripple path.This means that the BPSK modulation is to separate on 90 axles of spending at the axle with the former BPSK modulator to carry out.This structure is equivalent to carry out the QPSK modulation, and this is because radio frequency switch 903 is carried out the BPSK modulation at the I axle, and phase shifter 904 and radio frequency switch 905 are carried out the BPSK modulation on the Q axle.Herein, described synthesizing/distributed elements 902 is used for signal branch and synthetic.
In aforesaid embodiment, in side circuit, two radio frequency switches 903 and 905 one of them by short circuit so that ground connection.As selection, short circuit can form by the short-term structure of using λ/4 to open.
The QPSK modulation is carried out two carrier waves that branch forms by synthetic/902 pairs of signals that receive from antenna 901 of distributed elements, and a carrier wave is modulated by radio frequency switch 903, and another carrier wave is modulated by phase shifter 904 and radio frequency switch 905.The reflected signal of modulation is thus sent from antenna 901 once more via synthetic/distributed elements 902.
Described serial transducer 906 is converted to I and Q parallel signal to the data that serial sends.
More particularly, when the two bits of data according to serial conversion was " 00 ", radio frequency switch 903 and 905 two were turned off; When two data bits were " 01 ", radio frequency switch 903 was switched on separately; When described data bit was " 11 ", radio frequency switch 905 was switched on separately; When described data bit was " 10 ", radio frequency switch 903 and 905 two were switched on.
Flat 10-209914 Japan publication has proposed a kind of two-way aerial communication system, comprises interrogator and a plurality of labels that are arranged with interrogator space branch.The interrogator of the system that is proposed carries out the QPSK modulation to carrier wave (CW) radio signal transmission at least one label to the system according to information signal to subcarrier signal whereby.It should be noted that the system that proposed uses subcarrier signal to carry out the ASK modulation in the secondary modulation stage (for example referring to Fig. 3 application), described subcarrier signal has carried out the QPSK modulation in the initial modulation stage.In this case, described actual transfer rate is subjected to the restriction of the performance of employed ASK modulation method.In other words, the QPSK that system the adopted modulation that is proposed is provided with any improvement that is helpless to transfer rate.The system that is proposed is also inevitable with being offset the problem relevant with the blender noise with DC.According to the present invention, by contrast, main carrier wave is carried out the QPSK modulation based on following principle, described principle is: reflected channel back and forth provides phase difference thereon by allowing the input radio wave.Between system that above-mentioned institute cited application is proposed and structure of the present invention, exist obviously different thus.
Industrial applicibility
It should be understood that, though the present invention has been described with reference to accompanying drawing and in conjunction with specific embodiments, clearly, under the situation that does not break away from spirit of the present invention or scope, to those skilled in the art, according to foreground carry out manyly substituting, modifications and variations are conspicuous.
The present invention relates to a kind of heterogeneous modulator approach of using phase difference, described phase difference occurs between a plurality of reflected channel, and described reflected channel is that the form according to the communications setting that constitutes the backscattering type provides.Foregoing description relates generally to rfid system, and described rfid system has reader, is used for contactless mode tag read information internally.Yet this embodiment is not a limitation of the present invention.Except that data transmission applications, when the general RFID that system of the present invention is used for do not provide power supply uses, also very effective.
Thus, this detail that comprises in describing should not be counted as limitation of the scope of the invention, and only is some preferred embodiment of the present invention to be provided illustrate.Therefore, scope of the present invention should be determined by appended claims and jural equivalent thereof, rather than be determined by given example.
Claims (6)
1. a Wireless Telecom Equipment is used for carrying out data communication based on the backscatter system that uses the input radio-wave reflection, and described Wireless Telecom Equipment comprises data unit, and described data unit comprises:
Be used to receive and come from data and pass on the antenna of input radio wave of destination;
2
nIndividual channel, wherein for for unidirectional ripple path wherein, k channel provides (k-1) pi/2
nPhase difference, 1≤k≤2 wherein
nAnd
The reflection configuration apparatus for converting is used for forming by any channel of selecting described channel according to dateout and has 2
nThe reflected wave of individual out of phase;
Wherein said data unit uses described reflected wave to form described dateout with respect to the phase difference pattern of described input radio wave.
2. Wireless Telecom Equipment as claimed in claim 1 also comprises the first to the (2
n-1) individual phase shifter all provides λ/2 for each phase shifter for unidirectional ripple path wherein
N+1Phase difference, described phase shifter is connected in series to described antenna, wherein λ is a wavelength;
Wherein said 2
nIndividual channel comprises first channel that is used to obtain first reflected wave, described first reflected wave be the ripple path not by the situation of any described phase shifter under directly reflection input radio wave obtain, and comprise k the channel that is used to obtain k reflected wave, described k reflected wave has (k-1) pi/2 by the two-way ripple path between described first phase shifter and (k-1) individual phase shifter with respect to the phase place of described first reflected wave
N-1Phase shift, 1≤k≤2 wherein
nAnd
Wherein said reflection configuration apparatus for converting by described dateout being divided into every n bit increment and by coming to distribute phase place to reflected wave according to 0 and 1 combination selection channel in the n bit, carry out 2 with this
nPhase place PSK modulation.
3. Wireless Telecom Equipment as claimed in claim 2 also comprises first to the 2nd
nIndividual pip, described pip be between described antenna and described first phase shifter, between described (k-1) phase shifter and k the phase shifter, wherein 2≤k≤2
n-1, and be positioned at the (2
n-1) downstream of phase shifter;
Wherein said reflection configuration apparatus for converting by described dateout being divided into every n bit increment and switch described pip according to 0 and 1 combination in the n bit and come to distribute phase place to reflected wave, carry out 2 with this
nPhase place PSK modulation.
4. Wireless Telecom Equipment as claimed in claim 3, each in the wherein said pip all can or use open circuit termination to form by ground connection.
5. Wireless Telecom Equipment as claimed in claim 1 also comprises first to the 3rd phase shifter, all provides the phase difference of λ/8 for each phase shifter for unidirectional ripple path wherein, and described phase shifter is connected in series to described antenna, and wherein λ is a wavelength;
Wherein said 2
nIndividual channel comprises: be used to obtain first channel of first reflected wave, described first reflected wave by the ripple path not by the situation of any described phase shifter under directly the described input radio wave of reflection obtain; Be used to obtain the second channel of second reflected wave, described second reflected wave is by only having the phase shift of pi/2 with respect to the phase place of described first reflected wave via the two-way ripple path of described first phase shifter; Be used to obtain the 3rd channel of the 3rd reflected wave, described the 3rd reflected wave by via described first and the two-way ripple path of described second phase shifter have the phase shift of π with respect to the phase place of described first reflected wave; And the 4th channel that is used to obtain the 4th reflected wave, described the 4th reflected wave is by having the phase shift of 3 pi/2s via described first to the two-way ripple path of described the 3rd phase shifter with respect to the phase place of described first reflected wave; And
Wherein said reflection configuration apparatus for converting by described dateout being divided into per 2 bits increment and by coming to distribute phase place to reflected wave according to 0 and 1 combination selection channel in 2 bits, carry out the QPSK modulation with this.
6. Wireless Telecom Equipment as claimed in claim 5, wherein said reflection configuration apparatus for converting only use described first and described the 3rd channel carry out PSK modulation.
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| JP2003352223 | 2003-10-10 | ||
| JP352223/2003 | 2003-10-10 | ||
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| JP2001024549A (en) * | 1999-07-12 | 2001-01-26 | Matsushita Electric Ind Co Ltd | Mobile object identification system |
| US6456668B1 (en) * | 1996-12-31 | 2002-09-24 | Lucent Technologies Inc. | QPSK modulated backscatter system |
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|---|---|---|---|---|
| US6456668B1 (en) * | 1996-12-31 | 2002-09-24 | Lucent Technologies Inc. | QPSK modulated backscatter system |
| JP2001024549A (en) * | 1999-07-12 | 2001-01-26 | Matsushita Electric Ind Co Ltd | Mobile object identification system |
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| CN1717875A (en) | 2006-01-04 |
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