CN103560819A - Ofdm receiver apparatus - Google Patents
Ofdm receiver apparatus Download PDFInfo
- Publication number
- CN103560819A CN103560819A CN201310470750.0A CN201310470750A CN103560819A CN 103560819 A CN103560819 A CN 103560819A CN 201310470750 A CN201310470750 A CN 201310470750A CN 103560819 A CN103560819 A CN 103560819A
- Authority
- CN
- China
- Prior art keywords
- signal
- antenna
- ofdm
- receiving system
- predetermined threshold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 description 56
- 230000008569 process Effects 0.000 description 54
- 238000001514 detection method Methods 0.000 description 18
- 230000005540 biological transmission Effects 0.000 description 17
- 238000012545 processing Methods 0.000 description 13
- 230000009471 action Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000007812 deficiency Effects 0.000 description 2
- 238000005562 fading Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000000306 recurrent effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0805—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Radio Transmission System (AREA)
Abstract
An OFDM receiver apparatus for performing a diversity reception, wherein the power consumption and the cost can be reduced. An OFDM signal transmitted from a transmitter apparatus is received by two antennas (11A,11B). An antenna switching part (12) selectively outputs the signal, which was received by one of the two antennas, to a tuner (13). A signal outputted from the tuner (13) is supplied through an A/D converter (14), a quadrature detecting circuit (15) and through an FFT calculating circuit (16) to an equalizing circuit (17). A deviation determining circuit (21) calculates the positional deviations, on the constellation, of I and Q component signals outputted from the equalizing circuit (17). When the positional deviations exceed a predetermined threshold value (when the positional deviations of the signals are large), a deciding circuit (22) sends, to the antenna switching part (12), a control signal that instructs it to switch to the other antenna.
Description
Technical field
The present invention relates to the diversity receiving technology of OFDM (OFDM) signal.
Background technology
In Japanese surface wave digital television broadcasting, (OFDM (Orthogonal Frequency Division Multiplexing) mode is as transmission means to adopt OFDM.OFDM mode, is that transmitted signal is divided into a kind of of multicarrier transmission mode that a plurality of carrier waves send, and the frequency selective fading with multi-path transmission is strong, and the frequency spectrum of each subchannel can configure closely, efficiency of frequency employment advantages of higher.
In addition estimate from now on the digital television broadcasting that starts surface wave on portable set (1 section of broadcast).When pocket telephone that can receiving digital television in design and card form digital television receiver, conventionally all have to consider miniaturization and reduce power consumption.In addition, while portable set often moves receiving broadcast signal.During with portable set receiving broadcast signal, there are following two problems.
(1) antenna that is arranged on portable set is plain antenna.And in the situation that using portable device antenna, its receiving position is generally lower.Therefore, little to the tolerance limit of reception change of sensitivity, even if little variation occurs receiving position sometimes, will become and cannot receive.
(2) because portable set moves on one side, use on one side, the reception environment of relaying decline easily become.
Special problematic countermeasure in receiving for the signal that uses such portable set, can enumerate the countermeasure that what is called is carried out diversity reception.Adopting many antenna reception ofdm signals, is each branch signal to be made to front end synthesize or carry out synthetic method with subcarrier level.
Have again, as the prior art that relates to diversity receiver, have patent documentation 1.
Patent documentation 1: JP 2000-174726 communique
Summary of the invention
the problem to be solved in the present invention
Carry out the prior art of diversity reception, have the signal circuit scale of synthetic a plurality of systems to become large, receive the problem that LSI chip area and cost increase.In the portable set that carries out miniaturization, this problem needs to improve especially.
In addition, carry out the prior art of diversity reception, anyly all need a plurality of tuners.This is because must use the tuner processing with the corresponding setting of antenna separately with the signal of many antenna receptions.The diversity receiver of front end synthesis type, compares with the diversity receiver of subcarrier level synthesis type, and the circuit scale of demodulator is little, but necessity arranges two tuners, and this point does not become.And in the power generally consuming at receiver, the power ratio that tuner consumes surpasses 80%, the diversity receiving method before these, in order to adapt to the objects such as quality that improve restituted signal, the problem that has power consumption to increase.Particularly, in the portable set of strong request low-power consumption, this is the problem that must improve.
Therefore, in view of the above problems, the object of the invention is, provide a kind of when making every effort to reduce the power consumption of receiver and reducing costs, even in the mobile device and portable set that worsen at reception environment, also can demodulate the technology of high-quality signal.
the means of dealing with problems
The invention of recording for the claim 1 addressing the above problem is characterised in that, is provided with: 2 antennas that receive the signal of OFDM mode; Above-mentioned 2 antennas are alternatively switched, the signal of selected antenna reception is outputed to the switching part of tuner; The parts that the signal of tuner output is carried out to FFT computing; Signal after FFT computing carries out the parts of equilibrium treatment; Calculate the calculating unit of the position skew on the constellation of the signal after equilibrium treatment; And control assembly, these parts, when the skew of above-mentioned position surpasses predetermined threshold, send control signal to above-mentioned switching part, and selected antenna is switched to another root antenna, in the skew of above-mentioned position, drop to when following lower than above-mentioned predetermined threshold, continue to use selected antenna.
The invention that claim 2 is recorded is characterised in that, in the OFDM receiving system of recording in claim 1, above-mentioned calculating unit comprises the parts that on average calculate the position skew on the constellation of signal with whole carrier waves.
The invention that claim 3 is recorded is characterised in that, in the OFDM receiving system that claim 1 or claim 2 are recorded, above-mentioned calculating unit comprises with a plurality of symbols and averages, and calculates the parts of the position skew on the constellation of signal.
The invention that claim 4 is recorded is characterised in that, in the OFDM receiving system of recording in claim 3, the number of above-mentioned a plurality of symbols is less than 10 symbols.
The invention that claim 5 is recorded is characterised in that, the OFDM receiving system of recording in claim 3 with a plurality of symbols, average to calculate the above-mentioned parts of above-mentioned position skew, avoid the scheduled period after above-mentioned switching part alternatively switches above-mentioned 2 antennas and calculate the average of above-mentioned a plurality of symbols.
The invention that claim 6 is recorded is characterised in that, in the OFDM receiving system of recording in claim 5, the above-mentioned scheduled period is for more than at least 10 symbols.
The invention that claim 7 is recorded is characterised in that, in the OFDM receiving system of recording in claim 2, above-mentioned parts that above-mentioned calculating unit comprises, average to calculate the skew of above-mentioned position with full carrier, each symbol is averaged to calculate the above-mentioned parts of above-mentioned position skew with full carrier, each symbol averages and calculates the skew of above-mentioned position with full carrier; The above-mentioned parts of controlling the switching of above-mentioned antenna or continuing to use, the skew of above-mentioned position and above-mentioned predetermined threshold are compared, when predetermined symbolic number exists the skew of above-mentioned position to surpass above-mentioned predetermined threshold continuously, to above-mentioned switching part, send control signal, be controlled to selected above-mentioned antenna is switched to the above-mentioned antenna of another root, in above-mentioned position, skew surpasses above-mentioned predetermined threshold, but continuous symbolic number is less than above-mentioned predetermined symbol while counting, and is controlled to and continues to use selected antenna.
The invention that claim 8 is recorded, in the OFDM receiving system of recording in claim 7, above-mentioned predetermined symbolic number is the arbitrary symbolic number in 2 to 4.
The invention that claim 9 is recorded, is characterized in that being provided with: 2 antennas that receive OFDM mode signal; Above-mentioned 2 antennas are alternatively switched, the signal of selected antenna reception is outputed to the switching part of tuner; The parts of the signal quality of the signal of mensuration tuner output; And control assembly, these parts send control signal to above-mentioned switching part when above-mentioned signal quality drops to lower than predetermined threshold, be controlled to selected antenna is switched to another root antenna, when above-mentioned signal quality surpasses above-mentioned predetermined threshold, be controlled to and continue to use selected antenna.
The invention that claim 10 is recorded, is characterized in that being provided with: 2 antennas that receive the signal of OFDM mode; Above-mentioned 2 antennas are alternatively switched, the signal of selected antenna reception is outputed to the switching part of tuner; The parts that the signal of tuner output is carried out to FFT computing; Signal after FFT computing is carried out to the parts of equilibrium treatment; Signal after equilibrium treatment is carried out to the parts of demapping processing; Calculate the parts of the error rate of the signal after demapping is processed; And control assembly, these parts, when the above-mentioned error rate surpasses predetermined threshold, send control signal to above-mentioned switching part, be controlled to selected antenna is switched to another antenna, when the above-mentioned error rate drops to lower than above-mentioned predetermined threshold, be controlled to and continue to use selected antenna.
The invention that claim 11 is recorded, is characterized in that being provided with: 2 antennas that receive the signal of OFDM mode; Above-mentioned 2 antennas are alternatively switched, the signal of selected antenna reception is outputed to the switching part of tuner; Calculate the parts of C/N of the signal of tuner output; And control assembly, these parts, when above-mentioned C/N ratio drops to lower than predetermined threshold, send control signal to above-mentioned switching part, be controlled to selected antenna is switched to another root antenna, when above-mentioned C/N ratio surpasses above-mentioned predetermined threshold, be controlled to and continue to use selected antenna.
The invention that claim 12 is recorded, it is characterized in that, in the OFDM receiving system that any one is recorded in claim 1, claim 2, claim 9, claim 10 and claim 11, above-mentioned switching part separates the switching controls that antenna is carried out at more than predetermined symbol number interval.
invention effect
The present invention is the OFDM receiving system that is provided with 2 antennas, has the parts of measured signal quality, and alternatively selects the antenna that signal quality is good.Then, in tuner, receive only the signal of processing selected antenna output.Signal to tuner output carries out demodulation process.
Therefore, the present invention utilizes 2 antennas, and the good signal of the quality of reception, in addition, because receiving system is only established a tuner, is expected to reduce power consumption, reduces costs selectively.
In addition, the component computes of measured signal quality goes out the signal location skew of signal on constellation.Like this, when receiving signal and be interfered, can measured signal whether good, thus can select the antenna that signal quality is good.
In addition, the component computes of measured signal quality goes out the error rate of signal.Like this, can correctly reflect whether receive signal well selects antenna.
In addition, the present invention has the parts of calculating reception signal C/N ratio, can alternatively select C/N than good antenna.Then, on tuner, receive only and process from the signal of selected antenna output.
Like this, just, can from 2 antennas, use selectively the good antenna of accepting state.In addition, because receiving system is only established a tuner, be expected to reduce power consumption, reduce costs.
In addition, the present invention calculates the parts of position skew with a plurality of Symbol averages, with the number less than 10 symbols, on average calculates the position skew on the constellation of signal.Like this, can cut down the circuit structure of these parts.In addition, in transmission way, produce and disturb, when distortion occurs signal etc., can improve the antenna hand-off process adaptability of enforcement.In other words,, once distort, just can implement immediately the hand-off process of antenna in signal.
In addition, Symbol average value is calculated to be less than 10 Symbol averages, the degree of these 10 symbol deficiencies, the position skew for example, when low with Doppler frequency shift frequency on constellation become large during quite.
Therefore, during being calculated, Symbol average value comprises the Symbol average value of calculating in the situation during this signal distorts, when not comprising the Symbol average value of calculating in the situation during this signal distorts in Symbol average value computational process and compare, can make the poor of two Symbol average values become greatly.So, the setting of above-mentioned predetermined threshold becomes easily, therefore, is expected to improve the C/N ratio that receives signal.In addition, confirm by experiment, the setting of above-mentioned threshold value becomes easily, and the C/N of this reception signal ratio improves.
In addition, the present invention, after antenna alternatively switches, in the quiescent period being formed by the scheduled period, does not calculate the position skew on the constellation of signal.Like this, even increase because the hand-off process of antenna makes the position skew on constellation, overlapping during also can reducing this position skew and increasing and during the calculating of Symbol average value.
Like this, even increase because the hand-off process of antenna makes the skew of above-mentioned position, the impact that in the time of also can being suppressed at the mean value of compute sign, this position skew increases.
In addition, the skew of position on the constellation that antenna hand-off process causes become large during, be less than 10 symbols.Thereby, in the present invention, more than will (quiescent period) being set at least 10 symbols, the impact that in the time of can getting rid of compute sign mean value completely with this, antenna hand-off process causes.
In addition, the present invention carries out contraposition offset to each symbol and moves the comparison with predetermined threshold, offset in place moves ability switched antenna while surpassing predetermined threshold with continuous predetermined symbol number, when offset in place moves to be less than continuous predetermined symbol number over predetermined threshold, continues to use selected antenna.
Like this, just can make because disturbing, to cause distorting in signal in transmission way, during making that position skew on constellation increases, follow due to antenna hand-off process make position skew increase on constellation during overlapping.Thereby, even distort in signal, carry out antenna hand-off process, can by can receive normal signal during extend overlapping longlyer during above-mentioned two than not making.
In addition, predetermined symbolic number is the arbitrary symbolic number in 2 to 4.Here, the viewpoint based on correctly detecting the distortion in the signal that the interference that produces in transmission way causes sees, is preferably in and when position skew through constellation during the arbitrary symbolic number in 2 to 4 increases, carries out antenna hand-off process.Thereby, while can extend to greatest extent can consider above-mentioned item, receive normal signal during.
By following detailed description and accompanying drawing, can understand object of the present invention, feature, form and advantage.
Accompanying drawing explanation
Fig. 1 is the block diagram of the OFDM receiving system relevant to the 1st embodiment;
Fig. 2 represents the constellation of original signal;
Constellation when Fig. 3 represents 5% frequency shift (FS);
Fig. 4 represents that Doppler frequency is the constellation under the environment of 80Hz;
Fig. 5 represents the constellation under C/N=15dB environment;
Fig. 6 is the block diagram of the OFDM receiving system relevant to the 2nd embodiment;
Fig. 7 is the block diagram of the OFDM receiving system relevant to the 3rd embodiment;
Fig. 8 represents to start immediately to measure after antenna switches the situation of Symbol average value;
Fig. 9 is after antenna switches, and just starts to measure the situation of Symbol average value after the quiescent period;
Figure 10 represents before and after antenna hand-off process, the nonoverlapping situation of distortion that distortion originally and hand-off process cause;
Figure 11 is illustrated in before and after antenna hand-off process, the overlapping situation of distortion that distortion originally and hand-off process cause; And
Figure 12 is illustrated under the condition of predetermined symbolic number deficiency and occurs that continuously the position skew of calculating surpasses the situation of predetermined threshold.
Embodiment
Below, with reference to the accompanying drawings of embodiments of the invention.As the send mode of ground-wave digital broadcasting, the OFDM mode of the multiple transmission of hundreds of in a channel region～thousands of a plurality of carrier waves (subcarrier), is adopted in Japan and America and Europe.This OFDM mode, owing to being the multi-carrier modulation that becomes a plurality of subcarriers to send by sending Data Segmentation, efficiency of frequency employment is very high, and the frequency selective fading producing during mobile reception obtains terribly.In addition; under the identical condition of total bit rate of the bandwidth for transmission with 6MHz; compare with common single-carrier modulated mode; during the symbol of each carrier wave, can grow to and the corresponding degree of carrier number (hundreds of～thousands of); and the guard period that is called protective time slot (Guard Period) can be set between each significant character; the impact that can reduce multipath (ghost image) with this, has advantages of that can suppress image quality worsens.
the 1st embodiment
Fig. 1 is the functional block diagram of the OFDM receiving system of the 1st embodiment of the present invention.The OFDM receiving system of the present embodiment, is the receiving system that can be used for the portable set of pocket telephone, Portable digital television etc., receives a 1 segmented mode receiving system by 1 section of layer forming the ofdm signal that can form from multilayer.Then, the OFDM receiving system of the present embodiment, as shown in Figure 1, is to have 2 to have direction- sense antenna 11A, 11B, the receiving system that carries out diversity reception.
RF (radio frequency) signal that OFDM emitter (not shown) sends is received by 2 reception antennas by transmission path.The RF signal receiving, outputs to tuner 13 through antenna switching part 12, at tuner 13, carries out frequency inverted, becomes IF (intermediate frequency) signal.This IF signal, outputs to A/D converter through BPF (band pass filter), frequency mixer, LPF (low pass filter) etc.Be input to the signal of A/D converter 14, with the sample frequency of being scheduled to, be converted to digital signal.
Signal from A/D converter 14 outputs, outputs to the multiplier 151,152 that orthogonal demodulation circuit 15 has.Multiplier 151 by signal times with cosine wave, multiplier 152 by signal times with sine wave.Then, from multiplier 151,152, export separately the signal of in-phase component (I) and quadrature component (Q).In addition, the signal of I component and Q component is removed high fdrequency component by LPF153,154, outputs to FFT computing circuit 16.
Then, characteristic of the present invention is described.As mentioned above, the OFDM receiving system of the present embodiment is provided with 2 antenna 11A, 11B and antenna switching part 12.Antenna switching part 12 has from antenna switch control portion 20 reception control signals, the function that 2 antenna 11A, 11B are alternatively switched.In other words, antenna switching part 12, in the signal receiving, outputs to tuner 13 by the signal of selected antenna reception at 2 antenna 11A, 11B.
Antenna switch control portion 20 has offset detection circuit 21 and decision circuit 22, has utilization and from equalizing circuit 17 I components of output and the signal of Q component, carries out the function of antenna switching determination.
Offset detection circuit 21 is I component and Q component signals that input is exported from equalizing circuit 17, and detects the circuit of the position skew on constellation.
Constellation is that to take in-phase component (signal of I component) be transverse axis, and the quadrature component (signal of Q component) of take is the longitudinal axis, the configuration of performance signal.In the present embodiment, ofdm signal is the signal of QPSK modulation, and Fig. 2 to Fig. 5 represents the constellation of the signal of QPSK modulation.Fig. 2 is the constellation from the original signal of transmitter transmission.Like this, original signal is (I, Q)=(1,1), (1 ,-1), (1,1), the signal of any point in 4 points of (1 ,-1).Ofdm signal is interfered the process that sends to receiver reception from transmitter, receives the constellation of signal from above-mentioned 4 skews.For example, Fig. 3 is the constellation that the situation of 5% frequency shift (FS) has occurred, and Fig. 4 is the constellation of situation about receiving under 80Hz Doppler frequency environment, and Fig. 5 is the constellation being subject under the C/N=15dB environment of white Gaussian noise (AWGN).
Like this, with point, mark the position after reception signal 4 positions of original signal from constellation that are interfered are offset.Then, offset detection circuit 21, calculates the position skew on equalizing circuit 17 I components of output and the constellation of Q component signal by the operation method shown in formula 1.
In formula 1, N is 1 carrier number in symbol, and Ii is the I component (in-phase component) of i subcarrier, and Qi represents the Q component (quadrature component) of i subcarrier.In other words, in 1 symbol all in the signal of carrier waves, to (I, Q)=(1,1), (1 ,-1), and (1,1), the involution value summation of the distance that (1 ,-1) is 4, calculates its mean value.
For example, in glitch-free situation, for whole subcarriers, | Ii|=|Qi|=1, computing is R=0.In other words, be judged as and there is no signal skew, undistorted in signal.On the other hand, while having interference, R becomes the real number beyond 0, the position skew of detecting signal.So, I component or Q component from 1 more away from, mean deviation R is just larger, can be judged as reception situation and worsen.
Offset detection circuit 21, by the computing representing with formula 1, calculates the carrier wave mean value R of position skew, and this value is outputed to decision circuit 22.Decision circuit 22 adds up the numerical value of R in during tens of ms or hundreds of ms, obtains its mean value.In other words, in offset detection circuit 21, for the whole subcarriers in 1 symbol, obtain the mean value of signal location skew on constellation, in addition, in decision circuit 22, can obtain to a plurality of symbols the mean value of signal location skew.Formula 2 calculates in decision circuit 22, the Symbol average value R of signal location skew
avcformula.
In formula 2, Rk represents the carrier wave mean value of signal location skew in k symbol, and M represents the symbolic number of calculating object.For example, to every 50 symbols, calculate R
avc.
The control signal that decision circuit 22 sends can be carried out analog converting in D/A converter 23, as the control signal of simulating, sends to antenna switching part 12.Then, antenna switching part 12, carries out antenna switching controls according to the control signal of input.Like this, the Symbol average value R being offset at signal
avewhile surpassing predetermined threshold, in antenna 11A, 11B, be switched to present idle antenna, at Symbol average value R
avewhile dropping to lower than predetermined threshold, in antenna 11A, 11B, former state is selected the antenna of work now unchangeably.
Like this, adopt the present embodiment, can according to the position on the constellation of reception signal, be offset the distortion of decision signal, select the little antenna of distortion degree.
So, because 12 of the antenna switching parts signal by selected antenna reception outputs to tuner 13, therefore can be in 2 signals of diversity reception, to selecting the good signal of signal quality carry out demodulation.And, due to a tuner of OFDM receiving system use of the present embodiment, therefore be expected to reach low-power consumption and low cost.
Have, the switching controls of antenna is carried out at the interval that decision circuit 22 preferably separates predetermined symbol number (for example 50 symbols) again.This for example, switches for (, several symbols) in preventing during short antenna occurs continually, causes transmission path state seriously to change.
the 2nd embodiment
Then, the 2nd embodiment of the present invention is described.In the 2nd embodiment, according to the error rate (BER) that receives signal, carry out antenna switching controls.Fig. 6 is the OFDM receiving system block diagram relevant to the 2nd embodiment.In figure, the structure identical with the 1st embodiment uses the same reference numerals to represent.Below, the difference with the 1st embodiment is described.
As shown in Figure 6, this OFDM receiving system, has from the decision circuit 31 of FEC circuit 19 input bit error rate signals.Specifically, FEC circuit 19 is by the decode mistake of corrected signal of viterbi, but viterbi decoding circuit is when carrying out mistake correcting process, and the occurrence number of the faults occurring is counted.According to this count value, FEC circuit 19 just can be calculated the error rate.Then, this bit error rate signal is outputed to decision circuit 31, FEC circuit 19 just can carry out the relatively processing between the error rate and predetermined threshold at decision circuit 31.Then, decision circuit 31, when the error rate surpasses predetermined threshold (in other words, faults is many, in the situation of signal quality deteriorates), sends the control signal of switched antenna to antenna switching part 12.In addition, decision circuit 31, when the error rate drops to lower than predetermined threshold, (in other words, faults is few, in the good situation of signal quality), sends and continues to use the control signal of the antenna of work now antenna control assembly 12.
The control signal of sending from decision circuit 31 is carried out analog converting in D/A converter 23, as analog control signal, delivers to antenna switching part 12.Then, antenna switching part 12 carries out antenna switching controls according to the control signal of input.Like this, when the error rate of signal surpasses predetermined threshold, be switched to present idle antenna, when the error rate drops to lower than predetermined threshold, former state is selected the antenna of working now in antenna 11A, 11B unchangeably.
Like this, adopt the present embodiment, just can carry out switching controls according to the error rate that receives signal, select the good antenna of signal quality.So, because 12 of the antenna switching parts signal by selected antenna reception outputs to tuner 13, therefore in 2 signals of diversity reception, just may select the signal that signal quality is good to carry out demodulation.So, due to a tuner for OFDM receiving system of the present embodiment, therefore be expected to reach low-power consumption and low cost.
the 3rd embodiment
Then, the third embodiment of the present invention is described.In the 3rd embodiment, according to the C/N that receives signal than (Carrier to Noise ratio: carrier-to-noise ratio) carry out the switching of control antenna.Fig. 7 is the block diagram of the OFDM receiving system relevant to the 3rd embodiment.In figure, the structure identical with the 1st embodiment, represents with identical Reference numeral.Below, the difference with the 1st embodiment is described.
As shown in Figure 7, this OFDM receiving system is provided with C/N arithmetic unit 41, and C/N arithmetic unit 41 is calculated the C/N ratio that receives signal according to the operation result of fft circuit 16.C/N ratio is the ratio of signal to noise, and its value is higher, represents that signal power is stronger.In addition, C/N arithmetic unit 41, also the calculated signals C/N ratio before available FFT computing.Then, the C/N of the reception signal that C/N arithmetic unit 41 is calculated C/N outputs to decision circuit 42 than signal, in decision circuit 42, between C/N ratio and predetermined threshold, compares processing.Then, decision circuit 42, when C/N ratio drops to lower than predetermined threshold (in other words, noise is many, in the situation a little less than signal power), sends the control signal of switched antenna to antenna switching part 12.In addition, decision circuit 42, sends and continues to use the control signal of the antenna of work now to control assembly 12 at C/N when surpassing predetermined threshold (in other words, noise is few, in the strong situation of signal power).
The control signal that decision circuit 42 sends, can be in D/A converter 23 analog converting, as the control signal of simulation, be sent to antenna switching part 12.Then, antenna switching part 12, carries out antenna switching controls according to the control signal of input.Like this, when the C/N of signal ratio drops to lower than predetermined threshold, in antenna 11A, 11B, be switched on present idle antenna, when C/N ratio surpasses predetermined threshold, former state in antenna 11A, 11B, is selected the antenna of work now unchangeably.
Like this, adopt the present embodiment, just can carry out switching controls according to the C/N ratio that receives signal, selection can be received the antenna of strong signal power.And, because 12 of the antenna switching parts signal by selected antenna reception outputs to tuner 13, therefore in 2 signals of diversity reception, can select C/N to carry out demodulation than good signal.So the OFDM receiving system of the present embodiment, due to a tuner, is expected to reach low-power consumption and low cost.
Have, the switching controls of antenna is carried out at the interval that decision circuit 42 preferably separates predetermined symbol number (for example 50 symbols) again.This is for example, for (, several symbols) in preventing between short-term the switching of antenna occurs continually, makes transmission path state that large change occur.
the 4th embodiment
When Doppler frequency shift frequency is low (this is equivalent to the situation that hand-held OFDM receiving system is walked about and used), continuously through long-time, the position skew (R2 in formula 1) on constellation increases hardly.In other words, in the situation that Doppler frequency shift frequency is low, as a rule, during several symbols, after position skew (R2 of formula 1) on constellation increases relatively, during tens of symbols, the position skew (R2 in formula 1) on constellation reduces relatively.
Therefore, for example, in the situation that Doppler frequency shift frequency is low, in the formula 2 illustrating in the 1st embodiment, owing to measuring the mean value R of symbol in from tens of symbols to the scope during hundreds of symbols
avetherefore, can produce the problem that is difficult to above-mentioned predetermined threshold to be set as optimum value.
This be because, at Symbol average value R
avecalculating in, although also comprise that the skew of position on constellation increases relatively during, because its time is so small to have only several symbols, through tens of symbols, after hundreds of symbols, measuring Symbol average value R
avesituation under, this Symbol average value R
avereduce.Therefore, through tens of symbols, after hundreds of symbols, measuring Symbol average value R
avesituation under, comprise through in several mark signals, occur distortion during the Symbol average value R that calculates
ave, with not comprising, in this signal, there is not the Symbol average value R that the distortion time calculates
avebetween difference minimum.
In this case, for example,, when predetermined threshold is set as to relatively large numerical value, even if the relative increase of the several symbol times of the generation skew continuity of the position on constellation (in other words, even distort in during several symbols in signal), yet cannot detect the distortion of this signal.
On the other hand, when predetermined threshold is set as to relatively little numerical value, even if there is relatively little distortion (in other words in the skew of the position on constellation during tens of symbols, the viewpoint receiving from normal signal, continue the abnormal degree that can allow that is varied down in tens of mark signal cycles) situation under, still implemented the switching (in other words, having implemented antenna hand-off process frequently) of antenna.
The setting difficulty of predetermined threshold as described above, is consequently associated than worsening with the C/N that receives signal.In the present embodiment, provide the OFDM receiving system that addresses this problem use.
In other words, the decision circuit 22 that the OFDM receiving system of the present embodiment has, to be less than the position skew on the constellation that on average calculates signal of 10 symbols.In other words, in formula 2, M is less than 10, and decision circuit 22 just calculates the mean value R of a sub-symbol less than 10 symbols
ave.
The OFDM receiving system of the present embodiment, moves as follows.
Once the carrier wave mean value R of signal location skew is calculated in the computing that offset detection circuit 21 represents by formula 1, just this value is outputed to decision circuit 22.Decision circuit 22, the numerical value to R in the scheduled period adds up, and in addition, obtains its mean value.
More particularly, in offset detection circuit 21, to the whole subcarriers in 1 symbol, obtain the mean value (formula 1) of the position skew on signal constellation (in digital modulation), in addition, in decision circuit 22, to being less than 10 symbols (=M), obtain the mean value (formula 2) of signal location skew.
The control signal of sending from decision circuit 22 is carried out analog converting in D/A converter 23, as analog control signal, is sent to antenna switching part 12.Then, antenna switching part 12 carries out the switching controls of antenna according to the control signal of input.
Like this, the Symbol average value R being offset at signal
avewhen (the Symbol average value that is less than 10 Symbol averages) surpasses predetermined threshold, be switched in antenna 11A, 11B on present idle antenna, at Symbol average value R
avewhen (the Symbol average value that is less than 10 Symbol averages) drops to lower than predetermined threshold, former state is selected the antenna of work now unchangeably.
Like this, adopt the present embodiment, to be less than 10 symbols, on average calculate the position skew (in other words, M is less than 10 in formula 2) on the constellation that receives signal.
Therefore, can detect the reception signal distortion (as mentioned above, this phenomenon for example often occurs in the situation that Doppler frequency shift is low) that the skew of the position on constellation increases relatively during several symbols, above-mentioned predetermined threshold is convenient to set.
In other words, in the present embodiment, for example, can be when low with Doppler frequency shift frequency recurrent reception signal distortion during (in other words, several symbols left and right) suitable during, carry out Symbol average value R
avecalculating.
Therefore, will be at compute sign mean value R
avetime comprise this signal occur distortion during the Symbol average value R that calculates
ave, follow at Symbol average value R
avecalculating in the Symbol average value R that calculates during not comprising this signal and distorting
avecompared, can be increased two Symbol average value R
avepoor.Like this, just can make the setting of above-mentioned predetermined threshold become easy.
Like this, in the OFDM of the present embodiment receiving system, because the setting of above-mentioned predetermined threshold becomes easily, therefore be expected to improve the C/N ratio that receives signal.
Inventor changes the value of M in formula 2 and measures the C/N ratio that receives signal.As a result, to be less than 10 sign computation Symbol average R
avetime, the C/N ratio that receives signal can obtain improving more significantly.In addition, even be set to tens of symbols to the situation of hundreds of symbols with M value in formula 2, compare, if M value is set as being less than 10 symbols as the present embodiment, also more easily setting of predetermined threshold.
In addition, as mentioned above, in the present embodiment, the mean value R of compute sign within the scope of the symbolic number that is less than 10 symbols
ave.Therefore, with the mean value R that passes through tens of symbols or hundreds of sign computation symbols
avecarry out comparing in the situation of switching controls of antenna, the present embodiment can improve the adaptability that receives antenna hand-off process while there is distortion in signal, can also cut down the circuit scale of decision circuit 22.
the 5th embodiment
In the OFDM receiving system relevant with the various embodiments described above, while carrying out antenna hand-off process, continue several symbols (in symbol directional interpolation filter can treated length, be less than 10 symbols), due to this antenna hand-off process, the position skew on constellation becomes large.
Therefore, although in original (in other words, the factors such as interference in transmission way cause) reception signal, there is not distortion or distort little, by the Symbol average value R calculating immediately after antenna hand-off process
avewhile contrasting with predetermined threshold, there is the situation of the hand-off process of carrying out antenna.In other words, can again carry out because of the hand-off process of antenna the hand-off process of antenna.
Sometimes by the reception signal distortion receiving in hand-off process again selected antenna, going back of the signal receiving than the antenna before switching is large, and such situation (originally received in signal and occur distort or distort little situation of all carrying out antenna switching) does not preferably occur.
In the present embodiment, provide the OFDM receiving system that addresses this problem use.The OFDM receiving system of the present embodiment, above-mentioned switching part calculates average (formula 2) of a plurality of symbols again avoid the scheduled period after above-mentioned 2 antennas are alternatively switched after.
In other words, the offset detection circuit 21 that the OFDM receiving system of the present embodiment has or decision circuit 22, after antenna switching part 12 couples of 2 antenna 11A, 11B alternatively switch, in the quiescent period of the scheduled time, do not calculate the position skew on the constellation of signal.
Also have, after the above-mentioned quiescent period, in offset detection circuit 21, whole subcarriers in 1 symbol are obtained to the mean value (formula 2) of signal location skew on constellation, and, in decision circuit 22, a plurality of symbols are obtained to the mean value (formula 2) of signal location skew.
With the action comparison of relevant to the 1st embodiment below OFDM receiving system, the action of the OFDM receiving system of limit explanation the present embodiment.
Fig. 8 represents that the antenna of the OFDM receiving system relevant to the 1st embodiment switches an example of action.
Having selected under the state of antenna 11A, according to the step illustrating in the 1st embodiment, the result calculating according to offset detection circuit 21, the mean value R of decision circuit 22 compute signs
ave.22 couples of this Symbol average value R of decision circuit
avewith the comparison result of predetermined threshold, at Symbol average value R
avewhile surpassing predetermined threshold, implement the hand-off process of antenna, select antenna 11B.Then, after the hand-off process of this antenna, immediately according to the step illustrating in the 1st embodiment, decision circuit 22 is according to the result of calculation of the offset detection circuit 21 mean value R of compute sign again
ave.
Fig. 9 represents that the antenna of the OFDM receiving system of the present embodiment switches an example of action.
Having selected under the state of antenna 11A, according to the step illustrating in the 1st embodiment, decision circuit 22 is according to the result of calculation of offset detection circuit 21, the mean value R of compute sign
ave.22 couples of this Symbol average value R of decision circuit
avethe result that compares processing with predetermined threshold is Symbol average value R
avewhile surpassing predetermined threshold, implement the hand-off process of antenna, select antenna 11B.
Then, after this antenna hand-off process, within the scheduled period, offset detection circuit 21 and decision circuit 22 do not calculate the position skew on constellation.This scheduled time of not calculating the position skew on constellation is the quiescent period.
After this quiescent period, according to the step illustrating in the 1st embodiment, decision circuit 22 is according to the result of calculation of offset detection circuit 21, again the mean value R of compute sign
ave.
Like this, in the present embodiment, set the above-mentioned quiescent period.In other words, in the present embodiment, in the scheduled period after the hand-off process of antenna has just finished, do not calculate the position skew on constellation.
Therefore, even if antenna hand-off process causes position on constellation, skew increases, during also reducing this position skew and increasing with Symbol average value R
avecomputing interval overlapping.Like this, even increase because antenna hand-off process makes the skew of above-mentioned position, also can suppress Symbol average value R
avecalculating in the impact that increases of this position skew.
Have, as mentioned above, the above-mentioned position skew that the hand-off process of antenna causes, occurred in (more particularly, be less than 10 symbols during) during several symbols again.Therefore, more than the above-mentioned quiescent period is set as at least 10 symbols, thereby can get rid of Symbol average value R more completely
avecomputing interval is subject to the impact of antenna hand-off process.
In addition, as what illustrate in the 4th embodiment, the decision circuit 22 of the present embodiment also can be after the above-mentioned quiescent period, to being less than the Symbol average value R of 10 sign computation signal location skews
ave, and the Symbol average value R to predetermined threshold and this calculating
avecompare processing.
the 6th embodiment
Figure 10 represents that the antenna of the OFDM receiving system relevant to the 1st embodiment switches an example of action.
In Figure 10, selecting under the state of antenna 11A, due to the interference in transmission way etc., suppose to receive in signal, to have produced large distortion (following, the distortion that this reason is caused is called original distortion).X in Figure 10, the position skew on the constellation that represents to calculate by formula 1 surpasses the symbol of predetermined threshold.Suppose that original distortion is to produce in the process of several symbols, not distortion thereafter (or, suppose the viewpoint receiving from normal signal see very little and do not form problem).
Under above-mentioned condition, postulation formula 2 is carried out Symbol average value R after the scheduled period
avecalculating, and the Symbol average value R calculating according to this
avewith the result of predetermined threshold comparison, implemented the hand-off process of antenna, select antenna 11B.Wherein, as mentioned above, because the position skew (for simplicity, being referred to as the distortion that hand-off process causes) on the constellation of signal occurs to receive for the hand-off process of antenna.
But, after having carried out the action of Figure 10 explanation, produce problem shown below.In other words, from there is original distortion, implement hand-off process, switch and process the distortion causing, the distortion causing to this hand-off process can be out in the cold between, original distortion occur during and the distortion that causes of hand-off process occur during the summation time (shown in Figure 10 in the situation that, 16 symbolic numbers) during, OFDM receiving system becomes and cannot normally receive signal.
In the OFDM of the present embodiment receiving system, from the following description, can find out, in the situation that having implemented antenna hand-off process, can relatively shorten becomes cannot normally receive signal during.
The OFDM receiving system of the present embodiment, through predetermined symbolic number, when the position of each symbol that above-mentioned offset detection circuit 21 is calculated skew (formula 1) surpasses predetermined threshold, carries out antenna hand-off process continuously.
Below, with Figure 11, be described more specifically the action of the OFDM receiving system of the present embodiment.Wherein, Figure 11 represents that the antenna of the OFDM receiving system of the present embodiment switches an example of action.
Offset detection circuit 21, carrys out the position skew on average computation (formula 1) signal constellation (in digital modulation) to each symbol with whole carrier waves.Then, offset detection circuit 21 outputs to decision circuit 22 by this result of calculation.Decision circuit 22, to each symbol, is followed predetermined threshold comparison by the position skew (formula 1) of calculating in offset detection circuit 21.
As shown in figure 11, suppose and selecting, under the state of antenna 11A, original distortion to have occurred.In decision circuit 22, the above-mentioned result of relatively processing is, if continuous predetermined symbolic number (Figure 11 symbolic number is 2), above-mentioned position skew of calculating has surpassed predetermined threshold, and decision circuit 22 sends control signal to antenna switching part 12, switches reception antenna.
The control signal that decision circuit 22 sends is carried out analog converting in D/A converter 23, as analog control signal, is sent to antenna switching part 12.Then, antenna switching part 12 carries out the switching controls of antenna according to the control signal of input.Like this, in running order antenna is switched to antenna 11B from antenna 11A.
In contrast to this, different with Figure 11, in decision circuit 22, each symbol is carried out to the above-mentioned result of relatively processing, the symbolic number that surpasses predetermined threshold in the position skew of above-mentioned calculating is less than predetermined symbol continuously while counting, and decision circuit 22 just sends to antenna switching part 12 control signal that continues to use the antenna of working now.Thereby in antenna 11A, 11B, former state is selected the antenna (antenna 11A) of work now unchangeably.
For example, suppose that predetermined symbolic number is 3, the above-mentioned result of relatively processing that each symbol is carried out, above-mentioned position of calculating is offset continuous 2 symbols (with reference to Figure 12) and surpasses predetermined threshold.At this moment, decision circuit 22 just sends and continues to use the control signal of the antenna of work now to antenna switching part 12.Thereby in antenna 11A, 11B, former state is selected the antenna (antenna 11A) of work now unchangeably.
Like this, adopt the present embodiment, can, when the continuous predetermined symbolic number of above-mentioned calculating location skew surpasses predetermined threshold, implement antenna hand-off process.Therefore, can make to occur original distortion during with the distortion causing because of hand-off process during overlapping (with reference to Figure 11).
Thereby, compare with the situation of Figure 10, from implementing because of original distortion distortion that antenna hand-off process causes to antenna hand-off process disappears, OFDM receiving system become cannot normally receive signal during (in the situation that of Figure 11, during 10 symbolic numbers) shortened.
Have again, as seen from the above, due to occur original distortion during and the distortion that causes of hand-off process during overlapping, what must occur in original distortion carries out antenna hand-off process midway.
Generally, occur original distortion during, owing to being that observed result is at 2 more than symbolic number, 20 symbolic numbers following (when Doppler frequency shift frequency is low, (this is equivalent to the situation that hand-held OFDM receiving system is walked about and used) is that 10 symbolic numbers are following), arbitrary symbolic number more than above-mentioned predetermined symbolic number is preferably 2 symbolic numbers, in 20 symbols following (if the low situation of Doppler frequency shift frequency is that 10 symbolic numbers are following).
Have again, from being set as to greatest extent viewpoint above-mentioned overlapping time (in other words, by OFDM receiving system become cannot normally receive signal during be set as minimal viewpoint) and the measurement result done of inventor see, above-mentioned predetermined symbolic number is preferably 2～4 (the arbitrary symbolic numbers in 2 to 4).
In addition, in order to be unlikely the distortion causing because of hand-off process, implement antenna hand-off process, in the OFDM of the present embodiment receiving system, also can set the quiescent period illustrating in the 5th embodiment.
Above the present invention is explained in detail, but described above all aspect, be illustrative explanation, scope of the present invention is not limited to this.When knowing, without departing from the scope of the invention, it is contemplated that out a large amount of variation that do not illustrate.
Claims (5)
1. an OFDM receiving system, is characterized in that being provided with:
Receive 2 antennas (11A, 11B) of the signal of OFDM mode;
Described 2 antennas are alternatively switched and the signal of selected antenna reception are sent to the switching part (12) of tuner (13);
The parts (16) that the signal of described tuner output is carried out to FFT computing;
Signal after FFT computing is carried out to the parts (17) of equilibrium treatment;
Calculating unit (21) to the position skew on the calculated signals constellation after equilibrium treatment; And
When the skew of described position surpasses predetermined threshold, to described switching part, send control signal, be controlled to selected antenna to be switched to another root antenna, and when the skew of described position drops to lower than described predetermined threshold, be controlled to the parts (22) that continue to use selected antenna
Described calculating unit calculates the position skew on the constellation of signals to be less than a plurality of OFDM Symbol averages of 10 OFDM symbols,
Described predetermined threshold is set accordingly with the mean value that is less than the OFDM symbol of 10 OFDM symbols.
2. the OFDM receiving system that claim 1 is recorded, is characterized in that,
Described calculating unit on average calculates the position skew on the constellation of signal with the whole carrier waves in OFDM symbol.
3. the OFDM receiving system that claim 1 is recorded, is characterized in that,
In described calculating unit, avoid described switching part and alternatively switch scheduled period after described 2 antennas and calculate the average of described a plurality of OFDM symbols.
4. the OFDM receiving system that claim 3 is recorded, is characterized in that,
The described scheduled period is for more than at least 10 OFDM symbols.
5. the OFDM receiving system that claim 1 or claim 2 are recorded, is characterized in that,
Described switching part separates the switching controls that antenna is carried out at more than predetermined OFDM symbolic number interval.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005191664 | 2005-06-30 | ||
| JP2005-191664 | 2005-06-30 | ||
| JP2006-085881 | 2006-03-27 | ||
| JP2006085881A JP4859108B2 (en) | 2005-06-30 | 2006-03-27 | OFDM receiver |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2006800242979A Division CN101213768A (en) | 2005-06-30 | 2006-05-22 | OFDM receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103560819A true CN103560819A (en) | 2014-02-05 |
Family
ID=37604239
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310470750.0A Pending CN103560819A (en) | 2005-06-30 | 2006-05-22 | Ofdm receiver apparatus |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP4859108B2 (en) |
| KR (1) | KR101266804B1 (en) |
| CN (1) | CN103560819A (en) |
| WO (1) | WO2007004363A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116232438A (en) * | 2018-01-31 | 2023-06-06 | 松下电器（美国）知识产权公司 | Signal processing device, signal processing method, recording medium, and moving body |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008172577A (en) * | 2007-01-12 | 2008-07-24 | Honda Motor Co Ltd | Digital broadcast receiver |
| JP5261309B2 (en) * | 2009-07-29 | 2013-08-14 | 京セラ株式会社 | Wireless communication apparatus and antenna selection method |
| JP5161854B2 (en) * | 2009-09-29 | 2013-03-13 | 株式会社日立メディアエレクトロニクス | Receiving device, antenna switching circuit of receiving device, and tuner module of receiving device |
| JP2011124616A (en) | 2009-12-08 | 2011-06-23 | Renesas Electronics Corp | Communication device and method of processing communication |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3549178B2 (en) * | 1997-12-08 | 2004-08-04 | 株式会社日立国際電気 | Data transmission device control method and device |
| JP3779063B2 (en) * | 1998-05-28 | 2006-05-24 | 松下電器産業株式会社 | Wireless communication apparatus and wireless communication method |
| JP2001285156A (en) * | 2000-03-29 | 2001-10-12 | Clarion Co Ltd | Diversity receiver |
| JP3650334B2 (en) * | 2001-01-16 | 2005-05-18 | シャープ株式会社 | Digital broadcast receiver |
| JP3793448B2 (en) * | 2001-11-07 | 2006-07-05 | 株式会社日立製作所 | Receiver |
| JP2004112454A (en) * | 2002-09-19 | 2004-04-08 | Matsushita Electric Ind Co Ltd | Communication device and method |
| JP2005167873A (en) * | 2003-12-05 | 2005-06-23 | Pioneer Electronic Corp | Receiver, method of receiving, program for controlling receiving and recording medium |
-
2006
- 2006-03-27 JP JP2006085881A patent/JP4859108B2/en not_active Expired - Fee Related
- 2006-05-22 KR KR1020077030242A patent/KR101266804B1/en not_active Expired - Fee Related
- 2006-05-22 WO PCT/JP2006/310132 patent/WO2007004363A1/en not_active Ceased
- 2006-05-22 CN CN201310470750.0A patent/CN103560819A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116232438A (en) * | 2018-01-31 | 2023-06-06 | 松下电器（美国）知识产权公司 | Signal processing device, signal processing method, recording medium, and moving body |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4859108B2 (en) | 2012-01-25 |
| KR20080025693A (en) | 2008-03-21 |
| KR101266804B1 (en) | 2013-05-24 |
| WO2007004363A1 (en) | 2007-01-11 |
| JP2007043650A (en) | 2007-02-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7310503B2 (en) | Diversity reception device and diversity reception method | |
| US7123669B2 (en) | TPS decoder in an orthogonal frequency division multiplexing receiver | |
| US8116393B2 (en) | Method and apparatus for estimating channel state information | |
| JP4409743B2 (en) | Wireless communication apparatus and wireless communication system | |
| WO2009112560A2 (en) | Diversity reception | |
| JP4396423B2 (en) | OFDM receiver | |
| JP5076239B2 (en) | OFDM receiver | |
| US20100119019A1 (en) | Receiving apparatus and method, program and recording medium used for the same | |
| JP4657223B2 (en) | Modulation error calculation device and method, digital broadcast receiver, and digital broadcast wave measurement device | |
| EP0929960A2 (en) | Method for eliminating interference in an ofdm radio receiver | |
| US8670505B2 (en) | Early detection of segment type using BPSK and DBPSK modulated carriers in ISDB-T receivers | |
| CN103560819A (en) | Ofdm receiver apparatus | |
| US7106810B2 (en) | Method and apparatus for a demodulator circuit | |
| JP5395368B2 (en) | OFDM receiver | |
| CN101213768A (en) | OFDM receiver | |
| US20110243280A1 (en) | Receiver and receiving method | |
| CN102130872A (en) | Receiver, and method and device for eliminating co-channel interference | |
| US7664186B2 (en) | Channel decoding for multicarrier signal transmission by means of DC-offset and carrier-frequency offset-dependent weighting of reliability information | |
| US8885107B2 (en) | Signal processing device, signal processing method, and program for selectively processing a desired broadcast signal from a plurality of received broadcast signals | |
| JP2005191662A (en) | Method of demodulating ofdm signal | |
| JP4011384B2 (en) | Diversity receiver | |
| JP4546372B2 (en) | Reception device, transmission system, and reception method | |
| US8571156B2 (en) | Receiver apparatus | |
| JP2003143098A (en) | Ofdm signal reception quality evaluating device and method therefor | |
| JP2006345428A (en) | Receiving device, receiving method, receiving circuit, and program for digital communication / broadcasting |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20140205 |