WO2006075732A1 - 無線通信装置 - Google Patents
無線通信装置 Download PDFInfo
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- WO2006075732A1 WO2006075732A1 PCT/JP2006/300421 JP2006300421W WO2006075732A1 WO 2006075732 A1 WO2006075732 A1 WO 2006075732A1 JP 2006300421 W JP2006300421 W JP 2006300421W WO 2006075732 A1 WO2006075732 A1 WO 2006075732A1
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- code
- propagation path
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- 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
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- 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
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0602—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0204—Channel estimation of multiple channels
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
- H04L25/0226—Channel estimation using sounding signals sounding signals per se
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
- H04B17/318—Received signal strength
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
-
- 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
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
Definitions
- the present invention relates to a radio communication apparatus, and in particular, it is possible to accurately estimate a propagation path and correctly demodulate an information signal even if the influence of interference waves coming from adjacent cell forces is strong V and in a situation! It relates to possible wireless communication technology.
- OFDM Orthogonal Frequency Division Multiplexing
- Patent Document 1 shows a configuration example of a receiving device used in a communication system using the OFDM.
- FIG. 13 is a diagram illustrating a device configuration example of the receiver described in Patent Document 1.
- the receiver proposed in Patent Document 1 includes an antenna unit 1000, a GKGuard Interval) removal unit 1001, an FFT unit 1002, a demodulation unit 1003-1 to N, and P / S (Parallel to Serial) conversion unit 1004, selection unit 1005, switches 1006-1 to N, I FFT unit 1007, delay profile estimation unit 1008, and FFT unit 1009
- GKGuard Interval GKGuard Interval
- the received signal received by the antenna unit 1000 of the receiver shown in FIG. 13 is first removed from the guard interval by the GI removal unit 1001, and converted to a signal in the time domain by the FFT unit 1002 to a signal in the frequency domain. Is done. In this way, the FFT unit 1002
- the information signal of each subcarrier is sent to demodulation sections 1003-1 to N to be demodulated.
- a known pilot signal for propagation path estimation is usually included in a symbol or packet in addition to an information signal. Is selected and sent to the IFF T section 1007 via the switches 1006-1 to N.
- the pilot signal sent to IFFT section 1007 is converted from a frequency domain signal to a time domain signal, and delay profile estimation section 1008 estimates the delay profile of the propagation path.
- the propagation path delay profile thus estimated with the known pilot signal power is then converted into a frequency domain signal by the FFT unit 1009, and the frequency response of the propagation path can be obtained by this processing. it can.
- one transmission device uses a plurality of transmission antennas to implement transmission diversity technology. Even when it is used, the same code is used for propagation path estimation, and a technique for performing propagation path estimation and antenna identification with the same OFDM symbol is disclosed.
- An object of the present invention is to accurately estimate a propagation path and correctly demodulate an information signal even in the above situation.
- the transmission apparatus transmits OFDM symbols for channel estimation modulated with different codes for each transmission antenna at the same timing, and the receiver receives!
- the OFDM symbol for channel estimation is converted into frequency domain data, the code used in the transmitter is selected, complex conjugate is taken, and the frequency response of the channel is calculated by multiplying the obtained frequency domain data. .
- This signal is then converted to a time domain signal to calculate the propagation path delay profile. Furthermore, by applying an appropriate time window to the calculated delay profile and converting it to frequency domain data again, it is possible to estimate the frequency response of the highly accurate propagation path with reduced interference and at the same time identify the antenna. Enable.
- transmission antenna selection in transmission diversity is performed by applying the antenna identification technology described above.
- a transmission path estimation symbol using a different code for each antenna is transmitted, and transmission diversity for switching the transmission antenna is performed.
- the delay profile obtained using a predetermined code exceeds the power threshold, it is determined that the antenna using the corresponding code is used as a transmitting antenna.
- the number of transmitting antennas in the MIMO system is estimated on the receiving side.
- a propagation path estimation OFDM symbol modulated with a different code for each transmission antenna is received, converted into a frequency domain signal, and used in the transmission apparatus.
- the delay profile file is calculated by multiplying the complex conjugate signal of the code and converting it to a signal in the time domain. Then, by applying an appropriate time window to the obtained delay profile and converting it to a frequency domain signal again, it is possible to calculate the frequency response of the propagation path with high accuracy.
- a code to be multiplied by this receiving apparatus it is possible to simultaneously identify the transmitting antenna.
- base station identification and propagation path estimation can be performed by applying a highly accurate frequency response calculation method and transmission antenna identification method for each antenna to the cellular system.
- a propagation path estimation system can be improved by creating a replica of an interference wave propagation path estimation OFDM symbol and subtracting it from the received signal.
- the transmission antenna can be selected or switched.
- FIG. 1 is a diagram showing a configuration example of a packet used in each embodiment of the present invention.
- FIG. 2 is a diagram illustrating a configuration example of a transmission device on the base station side according to the first embodiment of the present invention.
- FIG. 3 is a diagram showing a configuration example of a terminal-side receiver according to the first embodiment of the present invention.
- FIG. 4 is a diagram showing an output waveform example of an IDFT unit.
- FIG. 5 is a flowchart showing a flow of a communication method according to the first embodiment of the present invention.
- FIG. 6 shows the configuration of a base station side transmission apparatus in an example in which the present invention is applied to radio communication technology in MIMO using a plurality of transmission / reception antennas in communication using radio communication technology according to the second embodiment of the present invention. It is a figure which shows an example.
- FIG. 7 is a functional block diagram showing a configuration example of a receiving device corresponding to FIG. 6.
- FIG. 8 is a flowchart showing a flow of propagation path estimation processing according to the present embodiment.
- FIG. 9 is a diagram showing a positional relationship of apparatuses in the radio communication technology according to the third embodiment of the present invention.
- FIG. 10 is a functional block diagram showing a configuration example of a receiving device according to a third embodiment of the present invention.
- FIG. 11 is a flowchart showing a signal processing flow of the receiving apparatus shown in FIG.
- FIG. 12 is a diagram showing a positional relationship between an OFDM symbol and each sample point.
- FIG. 13 is a diagram showing a device configuration example of a receiver shown in Patent Document 1.
- GI Guard Interval
- FIG. 1 is a diagram showing a configuration example of a packet used in each embodiment of the present invention.
- the packet format according to each embodiment of the present invention includes preamble A, preamble BX, and data.
- Preamble A is used for OFDM symbol synchronization or frequency synchronization.
- Preamble BX is mainly used for propagation path estimation.
- the time waveform of preamble BX is expressed by the following equation (1).
- the present invention is characterized in that a different preamble is transmitted for each transmitting antenna, and the receiving apparatus estimates a delay profile from each antenna, and further estimates a propagation path and specifies a transmitting antenna. Is.
- the code length N code for generating the preamble is Ckx and Cky
- the correlation between Ckx and Cky is expressed by the following equation (2).
- Cor ⁇ C k xx C k y * (2) Note that * means complex conjugate, and when selecting a different code for each antenna, it is preferable to select a code that reduces Cor.
- a wireless communication technique according to the first embodiment of the present invention will be described with reference to the drawings.
- a propagation path estimation symbol transmitted simultaneously with a plurality of antenna forces is set to a different sequence (preamble) for each antenna, so that the delay profile of the signal transmitted with each antenna force is obtained. Is calculated separately.
- the radio communication apparatus shows an example in which one transmission apparatus transmits data using a plurality of antennas, and in particular, the technique according to the present invention is applied to transmission diversity. .
- Fig. 1 is also a diagram showing an example of a packet format targeted by the radio communication technology according to the present embodiment.
- the packet according to the present embodiment includes a preamble A, a preamble BX, and data.
- preamble A is used for OFDM symbol synchronization and frequency synchronization
- preamble BX is used for antenna identification and channel estimation.
- These two preambles A and BX are both predetermined signals.
- the X of the force BX indicates that it is an antenna-specific preamble, and the data differs depending on the antenna, B0, B1, ... .
- the radio communication technology according to the first embodiment of the present invention is intended for downlink transmission
- the present invention relates to an antenna selection technique in which a plurality of antennas are provided on the transmission (base station) side and transmission antenna selection diversity is performed.
- the invention is not limited to this embodiment, but can be applied to uplink and other communications.
- OFDM symbols for channel estimation modulated with unique codes are simultaneously transmitted from a plurality of transmission antennas in a transmission apparatus.
- the propagation path estimation symbol transmitted with each antenna power is detected, and among the plurality of antennas used on the transmitting side, the signal transmitted with any antenna power has the best quality (reception power is This is an example of estimating the frequency response of the propagation path.
- FIG. 2 is a diagram illustrating a configuration example of a transmission apparatus on the base station side according to the present embodiment.
- the number of force antennas shown as an example of a device provided with two transmitting antennas is not limited.
- the base station side transmitting apparatus according to the present embodiment has a configuration corresponding to two antennas.
- error correction code part 1 S / P conversion part 2, mapping part 3, DFT (Discrete Fourier Transform) part (IFF T: Inverse Fast Fourier Transform may be used) 4, and P / S Conversion unit 5, GI (Guard Interval) insertion unit 6, Preamble (A, B0, B1) storage selection unit 11—a, 11 1>, switch units 12a, 12b, DZA conversion unit 13a 13b, radio units 14a and 14b, and antenna units 15a and 15b.
- the antenna selection information is antenna selection information based on a result notified from a communication destination terminal.
- the preamble (A, B0, B1) storage selection unit 11 assigns code A, code BO, and code B1 to each carrier, and uses a waveform subjected to OFDM signal processing. It is remembered.
- preamble (A, B0, B1) storage selection unit 11—a uses preamble A, BO power preamble (A, B0, B1) storage selection unit 11—b Will output preambles A and B1.
- Preamble (A, B0, B1) storage selection unit 11 when preamble 15 (A, B0, B1) is selected by antenna selection information Preamble A, B1 force preamble (A, B0, B1) storage selection unit 11—b Will output preambles A and BO. That is, the preamble (A, B0, B1) storage selection unit connected to the selected antenna outputs the preambles A and BO. [0033] Hereinafter, a case where the antenna 15-a is selected by the antenna selection information will be described. When transmitting data, the preamble is first transmitted, so the switch units 12-a and 12-b first select and transmit the preamble. At this time, preamble (A, BO, B1) storage selection unit 11—a outputs preambles A and BO, and preamble (A, B0, B1) storage selection unit 11—b selects preambles A and B1. Has been.
- the switch unit 12a After the preamble transmission is completed, the switch unit 12a performs switching, and the information data is transmitted from the error correction code unit 1 to the GI (guard interval) insertion unit 6 for the OFDM transmission processing data. select. On the other hand, no data is transmitted from the switch section 12-b after the preamble transmission.
- FIG. 3 shows that the terminal-side receiver according to this embodiment includes an antenna unit 41, a radio reception unit 42, an A / D conversion unit 43, a synchronization unit 44, a GI removal unit 45, and an S / P.
- preambles A, BO and A, B1 are transmitted simultaneously from different antennas.
- these preamplifiers are simultaneously received by one antenna 41 via different propagation paths.
- Signals that have passed through different propagation paths are input to the synchronization unit 44 via the radio reception unit 42 and the A / D conversion unit 43.
- symbol synchronization is established using the preamble A, and the subsequent processing is performed at an appropriate timing.
- the guard interval added on the transmission side is removed by the GI removal unit 45, it is converted into a parallel signal by the S / P conversion unit 46 and input to the DFT unit 47.
- the DFT unit 47 converts the received time domain signal into a frequency domain signal.
- the added frequency domain signal is input to the notch unit 54. This input data is RxB.
- a complex combination signal of code BO (a preamble transmitted from an antenna through which data is transmitted) is selected by code selection unit 55, and multiplication by RXB is performed by code multiplication unit 48.
- This signal is subjected to IDFT calculation by the IDFT unit 49.
- This signal can be handled as a delay profile from the antenna that sent the preamble BO (see below with reference to Fig. 4).
- the time window unit 50 removes unnecessary components, thereby cutting out noise 'interference components and extracting a desired delay profile with high accuracy.
- the frequency response can be obtained by selecting only valid information and performing DFT processing in the DFT unit 51. This determined frequency response allows subsequent data demodulation.
- the data demodulator 53 performs error correction and obtains transmission data.
- the code B1 is selected by the code selection unit 55, and the code multiplication unit 48 performs multiplication with RxB.
- the code multiplication unit 48 performs multiplication with RxB.
- FIG. 4 shows an output waveform example of the IDFT unit 49.
- Fig. 4 (a) shows the waveform when BO is used as the code
- Fig. 4 (b) shows the waveform when B1 is used as the code.
- the delay profiles from both antennas spread from t0 to t3.
- the power measurement unit 56 estimates the power from these delay profiles, and determines which of the antennas has a higher propagation path power.
- the base station is also notified of the transmitter power (not shown) as the antenna change information.
- communication is performed by changing the antenna as described above.
- FIG. 5 is a flowchart showing the above method.
- OFDM symbol synchronization is performed using preamble A in step S101.
- preamble region B (FIG. 2: B0 and B1 are added in this embodiment) is converted into frequency data by DFT.
- Step S103 Step Up to step S106 is a step of estimating each delay profile using IDFT from the preamble used for each antenna.
- step S103 RxB and B0 complex conjugate and multiplication are performed, the delay profile is estimated by IDFT, and in step S105, RxB and B1 complex conjugate and multiplication are performed.
- the delay profile is estimated by IDFT.
- Step S107 is a step of estimating the power of each transmitting antenna force from the delay profile estimated in step S106.
- Step S108 is a step of determining power information to be fed back to the transmission side, and in this embodiment, is a step of designating an antenna to be used for the next communication.
- step S111 valid data is extracted by a time filter from the delay profile of the antenna used as the transmitting antenna, and in step S112, the propagation path is estimated by DFT. Thereafter, in step S113, the data is demodulated and the process is terminated.
- the antenna selection preamble B1 is simultaneously transmitted to the preamble B0 necessary for data transmission, and by performing the above-described device configuration and processing, a new antenna estimation is performed.
- a transmission diversity system can be configured without requiring a long time. Further, according to this method, since the code of the antenna that transmits data is set to B0, it is possible to arbitrarily select an antenna on the transmission side even if there is no intensive antenna selection information.
- the antenna control system for transmission diversity shown here is a cellular system.
- the base station can be identified when considered as the antenna of each base station.
- the OFDM symbol for channel estimation modulated with the code specific to the antenna is transmitted from the transmission antenna of each base station, and the code for each antenna is switched as in the transmission apparatus of the first embodiment. There is no.
- the terminal When the terminal is in a position where radio waves of a plurality of base station power can be received (cell edge or sector edge, etc.), it receives the OFDM signal for channel estimation modulated with different codes transmitted simultaneously.
- the base station to be connected next is identified when the signal of the power of the currently connected base station becomes weak or the quality deteriorates. It is possible to keep.
- a guard interval is set for the OFDM signal, there is no problem if it is synchronized within a certain range that does not require complete synchronization.
- the power of two transmitting antennas is taken as an example.
- the number of base stations that can be received simultaneously is not necessarily two, and the codes used by the base stations are unknown. It is.
- a method of notifying information such as codes of surrounding base stations from the currently connected base station is taken. Based on this information, the terminal selects a code and then selects the base station to be connected next.
- the radio communication technology according to the present embodiment is an example in the case where the radio communication technology is applied to MIMO (Multi-Input Multi-Output: hereinafter referred to as MIMO) using a plurality of transmission / reception antennas in communication.
- MIMO Multi-Input Multi-Output
- FIG. 6 is a diagram illustrating a configuration example of a base station side transmission apparatus in a 2 ⁇ 2 (2: number of transmission antennas, 2: number of reception antennas) MIMO system according to the present embodiment.
- the information data processing system has two systems, and block 11 is replaced with block 21. Since the propagation path information between antennas is always required between all antennas, the same preamplifier is always transmitted from each antenna.
- the preamble (A, BO) is recorded from the antenna 15—a.
- FIG. 7 is a functional block diagram showing a configuration example of the receiving device according to the present embodiment.
- Fig. 7 shows only the functions related to propagation path estimation.
- To realize MIMO one more circuit configuration is required, but the configuration is omitted.
- blocks having the same functions as those in FIG. 3 are given the same numbers and explanation thereof is omitted, but there is almost no difference from the processing based on the configuration in FIG. The difference in processing is that for all codes (BO, B1), the response to the propagation path is always obtained, and the number of used antennas estimation unit 60 is added.
- the transmitting and receiving stations must know the number of antennas used.
- the radio communication technique according to the present embodiment has an antenna used estimation unit 60 shown in FIG. Based on the result of measuring the power of each delay profile by the power measurement unit 56 in the antenna used estimation unit 60, if the measured power is less than or equal to a predetermined threshold, the antenna using the preamble is used for data transmission. It can be determined that it has not been performed, and MIMO data can be demodulated.
- the number of transmitting antennas can be estimated by a receiving apparatus using OFDM symbols for channel estimation, and the number of antennas to be used needs to be notified in advance. Compared to this, an efficient communication system can be realized.
- FIG. 8 is a flowchart showing a flow of propagation path estimation processing according to the present embodiment. As shown in FIG. 8, the flowchart according to this embodiment also shows only the processing necessary for channel estimation, and the same processing is required for each antenna reception system. This flowchart shows the case where the number of transmission antennas is M, and preambles B0, Bl,..., BM-1 are preambles corresponding to the respective transmission antennas. Also, when transmitting with a reduced number of antennas, the number of antennas with the largest number of subscripts, ie, BM-1 and BM-2, is reduced in order.
- the DFT performs frequency conversion (RxB) of the preamble B region. These processes are the same as S101 and S102, respectively.
- step S203 the complex conjugate of RxB and code Bk (integer of 0 ⁇ k ⁇ M) is multiplied and the delay profile is estimated by IDFT in step S204.
- step S205 the power P is estimated from the delay profile, and in step S206, it is determined whether or not the power exceeds the threshold value. If the power does not exceed the threshold (no), the process ends.
- step S207 If the power exceeds the threshold value, the delay profile obtained by the code Bk is time-filtered in step S207, and the propagation path is estimated by DFT in step S208.
- step S209 it is determined whether or not k is equal to M ⁇ 1. If it is equal (yes), the process is terminated. If they are not equal (no), 1 is added to k in step S210, the process returns to step S203, and the process is repeated until the process in step S203 is completed.
- FIG. 9 is a diagram showing the positional relationship of the apparatus according to the present embodiment.
- each base station forms a cell and transmits and receives with one antenna. Is doing.
- Preamble B is generated by a unique code of each base station.
- An operation in the downlink channel from the base station to the mobile station will be described as an example.
- one base station BS-1, BS-2, and BS-3 is provided for each of the three cells.
- stations BS_1, BS-2, and BS-3 use the B0, Bl, and B2 preambles, respectively.
- the cell where the base station BS_1 is installed is called cell 1
- the cell where the base station BS-2 is installed is called cell 2
- the cell where BS-3 is installed is called cell 3.
- Base stations BS-1, BS-2, and BS-3 are synchronized in time, and the frequency bands used for communication are the same.
- FIG. 10 is a functional block diagram showing a configuration example of the receiving device according to the present embodiment.
- the receiver shown in FIG. 10 is configured to increase the accuracy of channel estimation for each base station force.
- this configuration can be realized, but the effect is most remarkable when the antenna of the base station is selected.
- the distance between the transmission device and the reception device is almost equal, and thus the reception power does not change greatly.
- antenna selection is performed for base stations that make up a cell, the distance between each base station and the mobile station differs, resulting in a large difference in received power.
- the configuration according to the present embodiment is effective.
- reference numeral 61 denotes a subtraction unit that subtracts two signals for each frequency
- reference numeral 62 denotes a propagation path storage unit
- reference numeral 63 denotes a code selection unit (2)
- reference numeral 64 denotes a code multiplication unit (2).
- Each has the same functions as the code selection unit 55 and the code multiplication unit 48.
- the propagation path is weak. Therefore, when estimating the propagation path from base station BS-2, the accuracy of the propagation path from base station BS-2 is improved by subtracting the received signal power from the component of preamble B0 of base station BS-1. can do.
- the received signal of the preamble BO transmitted from the base station BS-1 is This can be obtained by multiplying the propagation path information from the base station BS-1 stored in the propagation path storage unit 62 and the code of the preamble BO of the base station BS-1 selected by the code selection unit (2) 64.
- the subtracting unit 61 By calculating the received signal of the preamble BO by the subtracting unit 61, it is possible to estimate the propagation path from the base station BS-2 that is not affected by the preamble B of the base station BS-1. Furthermore, when estimating the propagation path from the base station BS-3, if the same operation is repeated, the propagation path from the base station BS-3 is affected by the base station BS-1 and the base station BS-2. It is possible to estimate without receiving it.
- the estimation order of the power transmission path in which the propagation paths are estimated in the order of the base stations BS-1, BS-2, BS-3 is not arbitrary, but is estimated in the order of higher performance. Is preferred.
- the order of higher performance is the order of reliability when communication is performed. In steady state (when connected to the base station), the propagation path of the desired base station is required, and then the reliability is increased. A propagation path with a base station having a propagation path that seems to be high is required. At the time of initial connection, the propagation paths with all connectable base stations are obtained, and then the propagation paths are obtained in the order of the reliability in the case of communication.
- the reception intensity may be simply used, or the signal to interference and noise power ratio (SINR) may be used.
- SINR signal to interference and noise power ratio
- Ptk is the power at the time tk of the obtained delay profile.
- steps S1 to S6 are steps for estimating a propagation path from the desired base station, and steps S11 to S16 are actually interfering stations.
- Step S21 to step S26 are steps for estimating the propagation path of interference station power
- step S31 is a step for estimating the propagation path of interference station power in memory, etc. It is a step to hold.
- Step S1 is a step of generating a waveform Fpre (k) obtained by DFT of the received preamble.
- k is an integer that satisfies 0 ⁇ k ⁇ N and is a subcarrier number.
- step S2 the signal obtained in step S1 is multiplied by Corg * (k), which is a complex conjugate of Corg (k), which is a code unique to the desired base station, and the resulting signal is Fdp ( k).
- Corg * (k) is a complex conjugate of Corg (k), which is a code unique to the desired base station
- Fdp (k) is the channel response of the desired base station, but it contains many interference components.
- t is a parameter indicating the time sample for k, and is an integer that satisfies 0 ⁇ k ⁇ N.
- This Timp (t) is the impulse response from the desired base station.
- step S4 Trimp (t) is calculated by multiplying Timp (t) by Twd (t), which is a time window.
- Frdp (k) is a value obtained by accurately calculating the propagation path of the desired base station force.
- step S6 the estimated propagation path is held in a memory or the like, and is used for V and data demodulation processing as shown.
- step S11 which is the next step after step S6, the propagation path having the desired base station power is subtracted from the preamble waveform obtained first (see the formula in the figure).
- the signal component to be subtracted The minutes are obtained by multiplying Frdp (k) by the code specific to the desired base station.
- the signal obtained in this step is a signal generated only from the interference signal and is defined as Fink).
- Step S12 is a step of multiplying the code of the base station that may cause all interference by the conjugate complex of the code in order to obtain the propagation path.
- the base station-specific code is represented by C (k, x)
- its complex conjugate is C * (k, X).
- X is an indicator indicating a base station. For example, if there are 10 codes, X is from 0 to 9.
- the propagation path from each interfering base station obtained in this step is indicated by Finfdp (k, x).
- Step S13 is a step of IDFTing Finfdp (k, x) for all X.
- Tinfdp (t, X) is calculated.
- Tinfdp (t, x) is the delay profile from each interfering base station.
- the power ratio Pin x) expressed by equation (3) is calculated.
- X is calculated such that Pin x)> 3 dB, and in the order of Pin x), the permutation is set to y.
- Step S21 to step S27 will be described.
- Step S27 following step S16 is a step of determining whether or not the propagation path estimation of the interference wave has been performed for all possible codes.
- Step S21 is a step in which w is decremented by 1 each time the loop turns.
- Step S22 is a step of obtaining the propagation path response of the interference wave that is considered to have the maximum power among the interference waves remaining as the interference wave component, and is the same processing as steps S2 and S12. As a result, the propagation path response of the interference wave with the maximum power at that time can be estimated.
- Step S23 is the same process as steps S3 and S13, and is a step in which IDFT processing is performed.
- Step S24 is the same process as step S4, and is a step in which a time window is set.
- Step S25 is the same processing as step S5, and the propagation path of the interfering base station having the code C (k, y) is known. This is stored in step S31.
- step S26 the interference wave component is removed and the loop is rotated again. This is the same processing as step S11.
- Figure 12 shows the positional relationship between the OFDM symbol and each sample point.
- the present embodiment is characterized by a time filtering method in the receiving apparatus.
- a delay profile is calculated from a preamble using an antenna-specific code that can be used in the radio communication technologies according to the first to third embodiments, and a propagation path is calculated. It can be applied to all systems that estimate
- each base station forms the cell shown in FIG. 9, and performs transmission / reception with one antenna.
- Preamble B is generated with a unique code for each base station.
- the base station power will also be described by taking the downlink channel to the mobile station as an example.
- temporal filtering reduces the degradation component due to noise as the filtering time is reduced, the filtering performance improves, but there is a problem that the estimation accuracy decreases when the signal component is removed.
- the present embodiment includes a method for adaptively performing this temporal filtering.
- the base station in a wireless communication system with a cell configuration, considering that there are base stations having various capabilities, the base station notifies the mobile station of information on the cell area such as transmission power.
- the mobile station is a method for setting time filtering.
- the time filtering when the base station constituting the wireless communication system communicates with the base station having the largest cell area, the time filtering is set to the guard interval length, and the time filtering time is shortened as the cell area becomes smaller.
- the second method is a method of changing the time filtering length based on the determination on the receiving device side.
- the present invention is applicable to a wireless communication system.
Abstract
Description
Claims
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JP2006553001A JP5024934B2 (ja) | 2005-01-17 | 2006-01-16 | 無線通信装置 |
CN200680008635XA CN101142775B (zh) | 2005-01-17 | 2006-01-16 | 无线电通信设备 |
EP06711702.8A EP1843498A4 (en) | 2005-01-17 | 2006-01-16 | WIRELESS COMMUNICATION ADVANTAGES |
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US (1) | US8451709B2 (ja) |
EP (1) | EP1843498A4 (ja) |
JP (2) | JP5024934B2 (ja) |
CN (2) | CN101958853B (ja) |
WO (1) | WO2006075732A1 (ja) |
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CN102761514B (zh) * | 2007-08-14 | 2015-07-15 | 株式会社Ntt都科摩 | 接收装置和数据取得方法 |
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JP2011155674A (ja) * | 2011-03-14 | 2011-08-11 | Sharp Corp | 無線通信システム、無線通信装置及び無線通信方法 |
WO2012133697A1 (ja) * | 2011-03-30 | 2012-10-04 | Necカシオモバイルコミュニケーションズ株式会社 | 受信装置および受信方法、ならびにコンピュータプログラム |
Also Published As
Publication number | Publication date |
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JP2011151852A (ja) | 2011-08-04 |
CN101142775B (zh) | 2013-05-29 |
CN101142775A (zh) | 2008-03-12 |
US20080112309A1 (en) | 2008-05-15 |
JP5024934B2 (ja) | 2012-09-12 |
EP1843498A1 (en) | 2007-10-10 |
JPWO2006075732A1 (ja) | 2008-06-12 |
CN101958853B (zh) | 2012-11-21 |
EP1843498A4 (en) | 2014-03-19 |
US8451709B2 (en) | 2013-05-28 |
CN101958853A (zh) | 2011-01-26 |
JP5351926B2 (ja) | 2013-11-27 |
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