WO2011155569A1 - Wireless communication system, transmitter, propagation path characteristic estimating apparatus, propagation path characteristic estimating method and program - Google Patents

Wireless communication system, transmitter, propagation path characteristic estimating apparatus, propagation path characteristic estimating method and program Download PDF

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WO2011155569A1
WO2011155569A1 PCT/JP2011/063272 JP2011063272W WO2011155569A1 WO 2011155569 A1 WO2011155569 A1 WO 2011155569A1 JP 2011063272 W JP2011063272 W JP 2011063272W WO 2011155569 A1 WO2011155569 A1 WO 2011155569A1
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signal
propagation path
transmission
receiver
value
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French (fr)
Japanese (ja)
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修 牟田
モハマド・イハブ・モハマド・モハメド
浩 古川
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国立大学法人九州大学
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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
    • H04B7/0413—MIMO systems
    • 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
    • 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
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03178—Arrangements involving sequence estimation techniques
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems

Definitions

  • a second aspect of the present invention is the first aspect, wherein the transmission sequence is a known sequence grasped in advance by the transmitter and the receiver, and the receiver has characteristics of the propagation path.
  • An initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path based on the received quantized signal.
  • a fifth aspect of the present invention is the fourth aspect, wherein a candidate value of each value X [n] of the transmission sequence is one of two values, and the differential operation unit A differential operation is performed to perform either of the formula (eq1) or the formula (eq2) according to odd / even, and the constant envelope modulation means performs FM modulation with a modulation index of 0.5,
  • the AD conversion means performs 1-bit analog-digital conversion processing for performing quantization by comparing the amplitude value of the received signal with a certain value and associating it with one of the candidate values.
  • Signal generation means for generating the transmission signal by performing modulation processing, and a transmission antenna for transmitting the transmission signal to the receiver, the signal generation means for each of the time series t n Corresponding to each value X [n] of the transmission sequence at time t n One constant phase, and at time t (t n-1 ⁇ t ⁇ t n ), by making the envelope constant at the same value as the envelope at time t n-1 or t n , the constant envelope Perform line modulation processing.
  • An AD conversion means for generating, based on the received quantized signal, an initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path, and a known signal indicating the known sequence ,
  • a duplicate signal generating means for generating a duplicate signal by quantizing an estimated received signal obtained via the estimated propagation path determined by the characteristic parameter, and an error for calculating a difference between the received quantized signal and the duplicate signal Total
  • estimated value calculating means for updating the characteristic parameter using a difference between the received quantized signal obtained by the error calculating means and the duplicate signal, and the duplicate signal generating means comprises the estimated value
  • the duplicate signal is further generated using the characteristic parameter updated by the calculation means.
  • the present invention may be regarded as a computer-readable recording medium for recording the program of the ninth aspect (steadily).
  • high-accuracy wireless communication can be realized by performing constant envelope modulation processing based on the phase. Therefore, it is possible not only to estimate the propagation path based on the initial estimated value but also to perform the propagation path estimation with higher accuracy by further performing iterative calculation.
  • FIG. 2 is a block diagram showing an outline of an initial value estimated value calculation circuit 91 which is an example of the initial estimated value calculation circuit 61 in FIG. 1.
  • 1 shows a block diagram of a wireless communication system 101 to be simulated. The BER characteristic when the maximum likelihood sequence estimation is performed using the estimated value of the propagation path characteristic is shown.
  • the transmitter 3 includes a transmission signal generation unit 10 that generates a transmission signal corresponding to a transmission sequence (an example of a “signal generation unit” in the claims of the present application), a power amplifier 13 that performs power amplification of the transmission signal, and a power amplifier 13.
  • the transmission antenna 15 (an example of “transmission antenna” in the claims of the present application) is provided.
  • phase There are four phases, 0, ⁇ / 2, ⁇ , and 3 ⁇ / 2, to which attention is paid in this embodiment.
  • the phases are A, B, C, and D, respectively.
  • candidate values 1 of X [n] correspond to phases A and B
  • candidate values ⁇ 1 correspond to phases C and D (that is, each candidate value of X [n] Phase is associated).
  • the phases A, B, A, B, A, B, C, respectively for the transmission series 1, 1, 1, 1, 1, 1, 1, ⁇ 1, ⁇ 1. D is assigned.
  • the two waveforms in FIG. 2 and the arrows in FIG. 3 show changes in phase in the sections a to h reaching each phase.
  • the constant envelope phase modulation processing is realized by setting the envelope to the same constant value as the envelope at time t n .
  • the receiver 5 receives a transmission signal transmitted from the transmitter 3 and performs signal processing, and a propagation path characteristic estimation section 33 that estimates the characteristics of the propagation path 7 (“propagation path characteristics” in the claims of this application).
  • a propagation path characteristic estimation section 33 that estimates the characteristics of the propagation path 7 (“propagation path characteristics” in the claims of this application).
  • the low resolution ADC 39 performs analog-digital conversion of low quantized bits (for example, 1 bit).
  • the ADC quantizes the amplitude value of the received signal.
  • the phase is quantized.
  • quantization noise is generated in the low resolution ADC 39.
  • Quantization noise is generally generated by AD conversion. This is particularly noticeable in low resolution ADCs.
  • the envelope amplitude of the transmission signal is constant. However, following different paths, multiple waves arrive. For this reason, the amplitudes of the received signals vary as they are synthesized. Thus, the quantization noise is noticeably generated in the amplitude. Therefore, as in the present invention, by performing constant envelope modulation processing using phase, even with a low resolution ADC, the generation of quantization noise can be suppressed and high-accuracy communication can be realized. .
  • the digital processing unit 41 includes a digital MIX unit 49 that converts an IF band signal into a baseband frequency, and an LPF (Low Pass Filter) unit 51 that performs low-pass filter processing on the output signal of the digital MIX unit 49.
  • LPF Low Pass Filter
  • Propagation path characteristics estimation section 33 an initial estimated value calculating circuit 61 for determining an initial estimate of the parameters H e [i] based on the received quantized signal (an example of "initial estimate calculation means” in the claims), known signal indicating a known sequence, "replication parameters H e replica signal generating unit 63 that the estimated received signal obtained through the estimation channel defined by [i] to generate a replica signal by quantizing (appended claims
  • An example of “signal generation means”, an error calculation unit 65 for calculating a difference between the received quantized signal and the duplicate signal an example of “error calculating means” in the claims
  • a received quantized signal and a duplicate signal update the parameter H e [i] using the difference, with a new parameter H e (1)
  • [i] estimated value calculating section 67 for determining a (an example of "estimation value calculation unit” of the claims).
  • Replica signal generating unit 63 uses the updated by the estimation value calculation unit 67 parameter H e (1) [i] , further generates a replica signal. According to the present invention, even with a low resolution ADC, it is possible to avoid quantization noise and transmit and receive with high accuracy. Therefore, it is possible to estimate the characteristics of the propagation path 7 with high accuracy by performing iterative calculation in the propagation path characteristic estimation unit 33.
  • a signal obtained by sampling the received quantized signal at a symbol period is represented as Y [n].
  • the initial estimated value calculation circuit 61 performs a correlation operation of Expression (4) on Y [n] to determine an initial estimated value.
  • N represents the number of known symbols.
  • L represents the number of correlators and has a relationship of M ⁇ L.
  • the number of passes M may be given a sufficiently large value in advance, for example.
  • the output H e [i] is the number of correlators that exceeds a certain threshold value Th may be M (i.e., of the output H e correlator exceeds a certain threshold value Th [i], the maximum of the i M- 1 may be determined).
  • the known signal generation unit 69, the estimated propagation path unit 71, the quantization unit 73, the digital MIX unit 75, and the LPF unit 77 are respectively connected to the transmitter 3, the propagation path 7, the low resolution ADC 39, the digital MIX unit 49, and the LPF unit 51. Correspond. Therefore, it can be said that the duplicate signal generated by the duplicate signal generation unit 63 is obtained by reproducing the same environment as the received quantized signal using the estimated propagation path.
  • the MIMO transmitter 215 transmits different transmission sequences A and B to the MIMO propagation path 216.
  • Transmission sequences A and B arrive at the reception point via different propagation paths.
  • the reception antenna 1 receives a composite wave of the transmission signal A that has passed through the propagation path 11 and the transmission signal B that has passed through the propagation path 21.
  • the reception antenna 2 receives a composite wave of the transmission signal A that has passed through the propagation path 12 and the transmission signal B that has passed through the propagation path 22.
  • the propagation path characteristics estimation unit 225 1 estimates the propagation paths 11 and 21, and the propagation path characteristic estimation unit 225 2 performs propagation path 12. , 22 is estimated. The same applies when the number of transmitting antennas and receiving antennas is three or more.
  • MIMO maximum likelihood sequence estimator 222 assumes that the characteristics of MIMO propagation path 216 and the configurations of transceivers 215 and 221 are known, and estimates a transmission sequence that is highly likely to be a transmission sequence from a plurality of transmission signal candidates.
  • J 1 is the candidate for the transmission signal A
  • Q is the total number of combinations of the candidates for the transmission signals A and B when the candidates for the transmission signal B are 1, 2 ,.
  • the selector 229 selects the combination of the transmission signals A and B with the smallest error.
  • FIG. 11 is a schematic block diagram relating to processing by the reception unit 307 1 and the propagation path characteristic estimation unit 309 1 of FIG.
  • the processing by the reception unit 307 2 and the propagation path characteristic estimation unit 309 2 in FIG. 10 can be similarly realized.
  • the configuration of the MIMO transmitter 310 is the same as that of the MIMO transmitter 215 of FIG.
  • the known signals 303 1 and 303 2 in FIG. 10 are generated, respectively.
  • the receiver 332 includes a receiving unit 307 1 and a propagation path characteristic estimating unit 309 1 . Configuration of the receiving unit 307 1 is the same as the receiver 31 of FIG. 1.
  • the error calculator 355 calculates the difference between the duplicate signal and the received quantized signal.
  • the estimated value calculation unit 357 obtains the mean square error (MMSE) of the duplicate signal and the received quantized signal, and derives the parameter of the channel that minimizes the error.
  • MMSE mean square error
  • the parameter derivation method for example, an iterative calculation method based on the LMS algorithm can be used.
  • Expressions (12) and (13) are examples of parameter update expressions.
  • the estimated value calculation unit 357 performs iterative calculation while updating the parameter for each W symbol.
  • e 11 (l) [n] and e 21 (l) [n] represent the error value of the nth symbol in the lth iteration.
  • ⁇ is the step size.
  • the duplicate signal generation unit 353 newly generates a duplicate signal using the updated He 11 (l + 1) [i] and He 21 (l + 1) [i]. The above iterative calculation is repeated until the

Abstract

Proposed are a communication system and the like that allows the quantization noises to be reduced even in a case of using a low resolution ADC. A transport signal generation unit (10) of a transmitter (3) performs, based on the phase, a constant envelope modulation, thereby generating a transport signal. A receiver (5) uses a low resolution ADC (39) to quantize the received signal. The low resolution ADC may cause the quantization noises to occur significantly. However, since the quantization noises significantly occur in the amplitude, a constant envelope modulation using the phase is performed, thereby allowing highly precise communications to be achieved, while avoiding the quantization noises, even in the case of using the low resolution ADC. Moreover, because of the achievability of highly precise wireless communications, a propagation path characteristic estimation unit (33) can more precisely perform a propagation path estimation by implementing repetitive calculations.

Description

無線通信システム、送信機、伝搬路特性推定装置、伝搬路特性推定方法及びプログラムWireless communication system, transmitter, propagation path characteristic estimation device, propagation path characteristic estimation method, and program
　本発明は、無線通信システム、送信機、伝搬路特性推定装置、伝搬路特性推定方法及びプログラムに関し、特に、送信機と受信機を備える無線通信システム等に関する。 The present invention relates to a wireless communication system, a transmitter, a propagation path characteristic estimation device, a propagation path characteristic estimation method, and a program, and more particularly to a wireless communication system including a transmitter and a receiver.
　次世代の無線通信システムにおいては、伝送速度の更なる高速化が求められる。しかしながら、無線基地局の出力電力の制約のために、アクセス回線の広帯域化にともない、各基地局の通信可能エリアは狭くなる。したがって、サービスエリア全体をカバーするためには膨大な数の基地局が必要となり、有線バックホール回線の敷設費用と併せて、インフラの設備投資額が増大する。基地局設置台数の増大に伴うインフラ敷設コスト増大を抑制するためには、簡易に設置可能な小型無線基地局と有線バックホール回線敷設コストを最小化する技術を開発することが重要となる。 In the next generation wireless communication system, further increase in transmission speed is required. However, due to restrictions on the output power of the radio base station, the communicable area of each base station becomes narrower as the access line becomes wider. Therefore, an enormous number of base stations are required to cover the entire service area, and the capital investment of infrastructure increases along with the cost of laying a wired backhaul line. In order to suppress the infrastructure laying cost increase accompanying the increase in the number of installed base stations, it is important to develop a small wireless base station that can be easily installed and a technology that minimizes the cost of laying a wired backhaul line.
　有線バックホール回線の敷設を抑制する技術として、無線マルチホップネットワーク（MESHネットワーク）技術が注目されている。MESHネットワークとは、基地局同士を無線で接続した通信システムのことである。このシステムでは、数局から十数局おきに有線回線に接続されたコア基地局１台を定め、これを起点に無線で中継接続された複数の基地局を設置する。コア基地局に多数の中継基地局を無線接続することで、有線回線の敷設コストを低減することができる。したがって、中継基地局数を増やすには、大容量の無線中継伝送技術が必要となる。 Wireless multi-hop network (MESH network) technology has attracted attention as a technology that suppresses the installation of wired backhaul lines. The MESH network is a communication system in which base stations are connected by radio. In this system, one core base station connected to a wired line is defined every several to a dozen stations, and a plurality of base stations that are wirelessly connected to the base station are installed. By connecting a large number of relay base stations to the core base station wirelessly, it is possible to reduce the cost of laying a wired line. Therefore, in order to increase the number of relay base stations, a large capacity wireless relay transmission technology is required.
　ところで、周波数資源は有限である。そのため、中継回線の広帯域化により通信容量を増加させることには限界があり、周波数利用効率の向上が必須である。周波数利用効率を向上させる技術として、MIMO（Multiple　Input　Multiple　Output）が注目されている。MIMO技術とは、複数の送受信アンテナを用いて、複数の信号を同一時刻・同一周波数で多重伝送する技術であり、例えば、IEEE802.11nの無線LANシステムにおいて標準採用されている。MESHネットワークの中継回線容量を増加するには、MIMO技術を適用することが有効である。 By the way, the frequency resources are finite. For this reason, there is a limit to increasing the communication capacity by increasing the bandwidth of the relay line, and it is essential to improve the frequency utilization efficiency. MIMO (Multiple Input Multiple Output) is attracting attention as a technology for improving frequency utilization efficiency. The MIMO technology is a technology that multiplex-transmits a plurality of signals at the same time and the same frequency using a plurality of transmission / reception antennas, and is adopted as standard in, for example, an IEEE802.11n wireless LAN system. It is effective to apply MIMO technology to increase the trunk line capacity of the MESH network.
　従来、無線通信システムにおいては、線形変調方式が採用されている。そして、出願人は、包絡線変調（例えばＦＭ変調など）のような非線形変調方式を提案した（特許文献１参照）。 Conventionally, linear modulation systems have been adopted in wireless communication systems. The applicant has proposed a nonlinear modulation system such as envelope modulation (for example, FM modulation) (see Patent Document 1).
　また、無線通信環境では、周囲からの反射波・遅延波などが到来する。そのため、受信信号に符号間干渉が生じ、これが通信品質を劣化させることが問題となる。符号間干渉の影響を除去する技術として、適応等化器が知られている。等化器の伝達特性を適切に定めるには、伝搬路特性を受信機側で高精度に推定することが重要である。出願人は、送信機が既知信号を送信し、受信機においてそれを観測することにより伝搬路特性を推定する方式を提案してきた（特許文献２参照）。 Also, in the wireless communication environment, reflected waves and delayed waves from the surroundings arrive. Therefore, intersymbol interference occurs in the received signal, which causes a problem that the communication quality deteriorates. As a technique for removing the influence of intersymbol interference, an adaptive equalizer is known. In order to appropriately determine the equalizer transfer characteristics, it is important to accurately estimate the propagation path characteristics on the receiver side. The applicant has proposed a method in which the transmitter transmits a known signal and observes it at the receiver to estimate the propagation path characteristics (see Patent Document 2).
特開２００９－８１７４５号公報JP 2009-81745 A 特開２００８－１１８４８３号公報JP 2008-118483 A
　一般的に、無線基地局の低消費電力化・小型化を実現するには、送信電力増幅器の電力効率を改善させることが大きな課題となる。しかしながら、従来の無線通信システムにおいて採用されている線形変調方式では、増幅器の入出力特性に高い線形性が求められるため（線形増幅を行う必要があるため）、増幅時の電力変換効率が非線形変調と比べて非常に低くなる。特に、無線LANや地上波デジタル放送において採用されているマルチキャリア方式では、送信信号が非常に高いピーク対平均電力比（PAPR：Peak-to-Average　Power　Ratio）を有するため、増幅器の所要バックオフ量が増加し、結果として電力変換効率がさらに大きく低下する。この問題に加えて、包絡線振幅に情報を有する線形変調システムでは、受信機の復調処理において高分解能アナログデジタル変換器（ADC：Analog-Digital　Converter）を必要とするため、ハードウェアの低消費電力化・小型化が困難となる。これらの問題点は、複数のアンテナ素子（送受信機）を有するMIMO伝送においてはさらに深刻になる。MIMOによる大容量中継伝送を提供するには、大きな装置負担を強いるこれらの課題の克服が必須の要件となる。 Generally, in order to realize low power consumption and downsizing of a radio base station, it is a big issue to improve the power efficiency of the transmission power amplifier. However, the linear modulation method employed in the conventional wireless communication system requires high linearity in the input / output characteristics of the amplifier (because it is necessary to perform linear amplification), so the power conversion efficiency during amplification is nonlinear modulation. It becomes very low compared with. In particular, in multi-carrier systems adopted in wireless LAN and terrestrial digital broadcasting, the transmitted signal has a very high peak-to-average power ratio (PAPR), so the required back-off of the amplifier The amount increases, and as a result, the power conversion efficiency is further greatly reduced. In addition to this problem, a linear modulation system with information in the envelope amplitude requires a high-resolution analog-digital converter (ADC) in the demodulation process of the receiver, which reduces the hardware power consumption. Downsizing and size reduction are difficult. These problems become more serious in MIMO transmission having a plurality of antenna elements (transceivers). In order to provide large-capacity relay transmission by MIMO, it is essential to overcome these problems that impose a heavy equipment burden.
　特許文献１は、上記の課題に対処するために、電力効率に優れる非線形送信電力増幅器及び低分解能ＡＤＣを用いて実現可能な定包絡線無線伝送方式を提案したものである。 Patent Document 1 proposes a constant envelope wireless transmission system that can be realized by using a non-linear transmission power amplifier and a low-resolution ADC that are excellent in power efficiency in order to cope with the above-described problems.
　また、伝搬路特性を推定するためには、従来の線形変調方式によるものでは、受信機において、高分解能ＡＤＣを用いて受信信号を観測する必要があった。また、特許文献１記載の定包絡線無線伝送方式による場合でも、遅延波などによる符号間干渉のために、受信信号の包絡線には変動を生じる。したがって、低分解能ＡＤＣを用いる場合、量子化による誤差（量子化雑音）が増加し、伝搬路特性を精度良く推定するのが困難となる。また、受信機側で非線形のＦＭ復調を行う場合、線形伝搬路の特性を推定するのが困難となる。したがって、従来の伝搬路特性推定器においては、受信機側において高分解能のＡＤＣを用いる必要があった。 Also, in order to estimate the propagation path characteristics, it is necessary to observe the received signal using a high-resolution ADC in the receiver using the conventional linear modulation method. Even in the case of the constant envelope wireless transmission system described in Patent Document 1, fluctuations occur in the envelope of the received signal due to intersymbol interference due to delayed waves and the like. Therefore, when a low resolution ADC is used, an error due to quantization (quantization noise) increases, and it is difficult to accurately estimate the propagation path characteristics. Further, when nonlinear FM demodulation is performed on the receiver side, it is difficult to estimate the characteristics of the linear propagation path. Therefore, in the conventional propagation path characteristic estimator, it is necessary to use a high-resolution ADC on the receiver side.
　そこで、本願発明は、低分解能ＡＤＣを用いた場合でも、量子化雑音を低減可能な無線通信システム等を提案することを目的とする。 Therefore, an object of the present invention is to propose a wireless communication system or the like that can reduce quantization noise even when a low-resolution ADC is used.
　本願発明の第１の観点は、送信機と受信機を備えた無線通信システムであって、前記送信機は、前記受信機に対して、送信系列Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）に対応する送信信号を無線通信により送信するものであり、前記送信系列の各値Ｘ［ｎ］は、複数の候補値の一つであり、前記各候補値には、予め、一つ又は複数の位相が対応付けられており、前記送信機は、位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、前記送信信号を前記受信機に対して送信する送信アンテナを有し、前記信号生成手段は、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行うものであり、前記受信機は、前記送信アンテナから送信された前記送信信号を、伝搬路を経由して受信する受信アンテナと、前記受信アンテナにおいて受信された受信信号を量子化して受信量子化信号を生成するＡＤ変換手段を有する。 A first aspect of the present invention is a wireless communication system including a transmitter and a receiver, and the transmitter transmits a transmission sequence X [n] (n = 0,..., N to the receiver). −1, N are the number of symbols)), and each value X [n] of the transmission sequence is one of a plurality of candidate values. Are associated with one or a plurality of phases in advance, and the transmitter performs a constant envelope modulation process based on the phase, and generates a transmission signal, and the transmission signal For the time series t n , the signal generating means has a phase associated with each value X [n] of the transmission series at each time t n as one of the envelope at time t (t n-1 <t <t n) time for the envelope t n-1 or t n The constant envelope modulation processing is performed by making the same value constant, and the receiver receives the transmission signal transmitted from the transmission antenna via a propagation path; AD conversion means for generating a received quantized signal by quantizing the received signal received by the receiving antenna.
　本願発明の第２の観点は、第１の観点であって、前記送信系列は、前記送信機及び前記受信機が予め把握している既知系列であり、前記受信機は、前記伝搬路の特性を推定する伝搬路特性推定手段を有し、前記伝搬路特性推定手段は、前記受信量子化信号に基づいて、前記伝搬路の特性を示す特性パラメータの初期推定値を定める初期推定値計算手段と、前記既知系列を示す既知信号が、前記特性パラメータにより定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成手段と、前記受信量子化信号と前記複製信号との差を計算する誤差計算手段と、前記受信量子化信号と前記複製信号との差を用いて前記特性パラメータを更新する推定値計算手段を有し、前記複製信号生成手段は、前記推定値計算手段により更新された前記特性パラメータを用いて、前記複製信号をさらに生成する。 A second aspect of the present invention is the first aspect, wherein the transmission sequence is a known sequence grasped in advance by the transmitter and the receiver, and the receiver has characteristics of the propagation path. An initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path based on the received quantized signal. , A known signal indicating the known sequence, a duplicate signal generating means for generating a duplicate signal by quantizing an estimated received signal obtained via an estimated propagation path determined by the characteristic parameter, the received quantized signal, and the An error calculating means for calculating a difference with a duplicate signal, and an estimated value calculating means for updating the characteristic parameter using a difference between the received quantized signal and the duplicate signal, wherein the duplicate signal generating means is Estimated Using the characteristic parameters updated by the calculation means further generates the replica signal.
　本願発明の第３の観点は、第２の観点であって、前記初期推定値計算手段は、Ｌ個の相関器を有し、前記Ｌ個の相関器のうち、所定の閾値を超える相関器の出力の個数Ｍをパス数として推定し、前記受信量子化信号をシンボル周期でサンプリングした信号Ｙ［ｎ］に対して、相関演算を行うことにより、前記特性パラメータの初期推定値を定めるものであり、前記伝搬路特性推定手段が、パス数Ｍ及び初期推定値、並びに、前記誤差計算手段により得られた前記受信量子化信号と前記複製信号との差に基づいて前記特性パラメータを更新するものである。 A third aspect of the present invention is the second aspect, wherein the initial estimated value calculation means includes L correlators, and among the L correlators, a correlator that exceeds a predetermined threshold value. The initial estimation value of the characteristic parameter is determined by performing a correlation operation on a signal Y [n] obtained by sampling the received quantized signal at a symbol period. And the propagation path characteristic estimating means updates the characteristic parameter based on the number of paths M and the initial estimated value, and the difference between the received quantized signal and the duplicate signal obtained by the error calculating means. It is.
　本願発明の第４の観点は、第２又は第３の観点であって、前記信号生成手段は、前記送信系列に対して差動演算を行う差動演算手段と、前記差動演算手段の演算結果を示す差動演算信号に対して定包絡線変調を行う定包絡線変調手段を有する。 A fourth aspect of the present invention is the second or third aspect, wherein the signal generation means includes a differential operation means for performing a differential operation on the transmission sequence, and an operation of the differential operation means. Constant envelope modulation means for performing constant envelope modulation on the differential operation signal indicating the result is provided.
　本願発明の第５の観点は、第４の観点であって、前記送信系列の各値Ｘ［ｎ］の候補値は、２つの値のいずれかであり、前記差動演算部は、ｎの奇偶に応じて式(eq1)又は式(eq2)のいずれかを行う差動演算を行うものであり、前記定包絡線変調手段は、変調指数０．５のＦＭ変調を行うものであり、前記ＡＤ変換手段は、前記受信信号の振幅の値と一定の値を比較して、前記候補値のいずれかに対応付けることにより、量子化を行う１ビット・アナログデジタル変換処理を行うものである。 A fifth aspect of the present invention is the fourth aspect, wherein a candidate value of each value X [n] of the transmission sequence is one of two values, and the differential operation unit A differential operation is performed to perform either of the formula (eq1) or the formula (eq2) according to odd / even, and the constant envelope modulation means performs FM modulation with a modulation index of 0.5, The AD conversion means performs 1-bit analog-digital conversion processing for performing quantization by comparing the amplitude value of the received signal with a certain value and associating it with one of the candidate values.
　本願発明の第６の観点は、受信機に対して、送信系列Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）に対応する送信信号を無線通信により送信する送信機であって、前記送信系列の各値Ｘ［ｎ］は、複数の候補値の一つであり、前記各候補値には、予め、一つ又は複数の位相が対応付けられており、前記受信機は、前記送信機から送信された前記送信信号を受信する受信アンテナと、前記受信アンテナにおいて受信された受信信号を量子化するＡＤ変換手段を有するものであり、位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、前記送信信号を前記受信機に対して送信する送信アンテナを有し、前記信号生成手段が、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行う。 A sixth aspect of the present invention is a transmission in which a transmission signal corresponding to a transmission sequence X [n] (n = 0,..., N−1, N is the number of symbols) is transmitted to a receiver by wireless communication. Each value X [n] of the transmission sequence is one of a plurality of candidate values, and each candidate value is associated with one or more phases in advance, The receiver includes a reception antenna that receives the transmission signal transmitted from the transmitter, and AD conversion means that quantizes the reception signal received by the reception antenna, and is based on a phase and has a constant envelope. Signal generation means for generating the transmission signal by performing modulation processing, and a transmission antenna for transmitting the transmission signal to the receiver, the signal generation means for each of the time series t n Corresponding to each value X [n] of the transmission sequence at time t n One constant phase, and at time t (t n-1 <t <t n ), by making the envelope constant at the same value as the envelope at time t n-1 or t n , the constant envelope Perform line modulation processing.
　本願発明の第７の観点は、送信機が送信系列に基づいて生成して無線送信し、受信機が受信して得られた受信信号を用いて伝搬路の特性を推定する伝搬路特性推定装置であって、前記送信系列の各値Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）は、複数の候補値の一つであり、前記各候補値には、予め、一つ又は複数の位相が対応付けられており、前記送信系列は、前記送信機及び前記受信機が予め把握している既知系列であり、前記送信機は、位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、前記送信信号を前記受信機に対して送信する送信アンテナを有するものであり、前記信号生成手段は、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行うものであり、前記受信機は、前記送信アンテナから送信された前記送信信号を、伝搬路を経由して受信する受信アンテナと、前記受信アンテナにおいて受信された受信信号を量子化して受信量子化信号を生成するＡＤ変換手段を有するものであり、前記受信量子化信号に基づいて、前記伝搬路の特性を示す特性パラメータの初期推定値を定める初期推定値計算手段と、前記既知系列を示す既知信号が、前記特性パラメータにより定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成手段と、前記受信量子化信号と前記複製信号との差を計算する誤差計算手段と、前記誤差計算手段により得られた前記受信量子化信号と前記複製信号との差を用いて前記特性パラメータを更新する推定値計算手段を有し、前記複製信号生成手段は、前記推定値計算手段により更新された前記特性パラメータを用いて、前記複製信号をさらに生成する。 A seventh aspect of the present invention is a propagation path characteristic estimation device in which a transmitter generates and transmits wirelessly based on a transmission sequence, and a propagation path characteristic is estimated using a reception signal obtained by reception by a receiver. Each value X [n] (n = 0,..., N−1, N is the number of symbols) of the transmission sequence is one of a plurality of candidate values, and each candidate value includes: One or a plurality of phases are associated with each other in advance, and the transmission sequence is a known sequence grasped in advance by the transmitter and the receiver, and the transmitter has a constant envelope based on the phase. The signal generation means for generating the transmission signal by performing modulation processing, and a transmission antenna for transmitting the transmission signal to the receiver, the signal generation means for the time series t n At each time t n , one of the phases associated with each value X [n] of the transmission sequence The constant envelope modulation processing is performed by making the envelope constant at the same value as the envelope at time t n-1 or t n at time t (t n-1 <t <t n ). The receiver receives the transmission signal transmitted from the transmission antenna via a propagation path, quantizes the reception signal received by the reception antenna, and generates a received quantized signal. An AD conversion means for generating, based on the received quantized signal, an initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path, and a known signal indicating the known sequence , A duplicate signal generating means for generating a duplicate signal by quantizing an estimated received signal obtained via the estimated propagation path determined by the characteristic parameter, and an error for calculating a difference between the received quantized signal and the duplicate signal Total And estimated value calculating means for updating the characteristic parameter using a difference between the received quantized signal obtained by the error calculating means and the duplicate signal, and the duplicate signal generating means comprises the estimated value The duplicate signal is further generated using the characteristic parameter updated by the calculation means.
　本願発明の第８の観点は、送信機が送信系列に基づいて生成して無線送信し、受信機が受信して得られた受信信号を用いて伝搬路の特性を推定する伝搬路特性推定方法であって、前記送信系列の各値Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）は、複数の候補値の一つであり、前記各候補値には、予め、一つ又は複数の位相が対応付けられており、前記送信系列は、前記送信機及び前記受信機が予め把握している既知系列であり、前記送信機は、位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、前記送信信号を前記受信機に対して送信する送信アンテナを有するものであり、前記信号生成手段は、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行うものであり、前記受信機は、前記送信アンテナから送信された前記送信信号を、伝搬路を経由して受信する受信アンテナと、前記受信アンテナにおいて受信された受信信号を量子化して受信量子化信号を生成するＡＤ変換手段と、前記伝搬路の特性を推定する伝搬路特性推定手段を有するものであり、前記伝搬路特性推定手段は、前記受信量子化信号に基づいて、前記伝搬路の特性を示す特性パラメータの初期推定値を定める初期推定値計算手段と、前記既知系列を示す既知信号が、前記特性パラメータにより定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成手段と、前記受信量子化信号と前記複製信号との差を計算する誤差計算手段を有し、推定値計算手段が、前記誤差計算手段により得られた前記受信量子化信号と前記複製信号との差を用いて前記特性パラメータを更新する推定値計算ステップと、前記複製信号生成手段が、前記推定値計算手段により更新された前記特性パラメータを用いて、前記複製信号をさらに生成するステップを含む。 An eighth aspect of the present invention is a propagation path characteristic estimation method in which a transmitter generates and wirelessly transmits based on a transmission sequence, and a propagation path characteristic is estimated using a received signal received by a receiver. Each value X [n] (n = 0,..., N−1, N is the number of symbols) of the transmission sequence is one of a plurality of candidate values, and each candidate value includes: One or a plurality of phases are associated with each other in advance, and the transmission sequence is a known sequence grasped in advance by the transmitter and the receiver, and the transmitter has a constant envelope based on the phase. The signal generation means for generating the transmission signal by performing modulation processing, and a transmission antenna for transmitting the transmission signal to the receiver, the signal generation means for the time series t n At each time t n , one of the phases associated with each value X [n] of the transmission sequence The constant envelope modulation processing is performed by making the envelope constant at the same value as the envelope at time t n-1 or t n at time t (t n-1 <t <t n ). The receiver receives the transmission signal transmitted from the transmission antenna via a propagation path, quantizes the reception signal received by the reception antenna, and generates a received quantized signal. The AD conversion means to generate and the propagation path characteristic estimation means for estimating the propagation path characteristics, the propagation path characteristic estimation means indicate the propagation path characteristics based on the received quantized signal. An initial estimated value calculation means for determining an initial estimated value of a characteristic parameter, and a known signal indicating the known sequence quantizes an estimated received signal obtained via an estimated propagation path determined by the characteristic parameter to generate a duplicate signal Do A signal generation means, and an error calculation means for calculating a difference between the received quantized signal and the duplicate signal, and an estimated value calculating means and the received quantized signal obtained by the error calculating means and the duplicate An estimated value calculating step of updating the characteristic parameter using a difference from a signal, and a step of the replica signal generating means further generating the duplicate signal using the characteristic parameter updated by the estimated value calculating means including.
　本願発明の第９の観点は、コンピュータにおいて、第８の観点の伝搬路特性推定方法を実現させるためのプログラムである。 A ninth aspect of the present invention is a program for causing a computer to realize the propagation path characteristic estimation method according to the eighth aspect.
　なお、本願発明を、第９の観点のプログラムを（定常的に）記録するコンピュータ読み取り可能な記録媒体として捉えてもよい。 Note that the present invention may be regarded as a computer-readable recording medium for recording the program of the ninth aspect (steadily).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　本願発明によれば、位相に基づいて定包絡線変調処理を行うことにより、送信信号を生成する。送信信号は、異なる経路をたどり、受信機に到達する。受信機では、複数の波が到来するため、受信信号の振幅は、それらが合成されて変動する。そのため、量子化雑音は、振幅に顕著に発生することとなる。特に、低分解能ＡＤＣでは、量子化雑音は顕著に生じる。しかしながら、本願発明にあるように、振幅ではなく、位相を用いた定包絡線変調処理を行うことにより、低分解能ＡＤＣであっても、量子化雑音を避け、高精度な通信を実現することが可能となる。さらに、受信機において低分解能ＡＤＣを用いることで、受信機の回路規模を大幅軽減可能となる。特に、１ビットＡＤＣを利用する場合は、受信器での利得調整（AGC：Automatic　Gain　Control）が不要となり、低消費電力化に有利となる。 According to the present invention, a transmission signal is generated by performing constant envelope modulation processing based on the phase. The transmitted signal follows a different path and reaches the receiver. Since a plurality of waves arrive at the receiver, the amplitude of the received signal fluctuates by combining them. Therefore, the quantization noise is remarkably generated in the amplitude. In particular, quantization noise is noticeably generated in a low resolution ADC. However, as in the present invention, by performing constant envelope modulation processing using phase instead of amplitude, even with a low resolution ADC, it is possible to avoid quantization noise and realize highly accurate communication. It becomes possible. Furthermore, by using a low resolution ADC in the receiver, the circuit scale of the receiver can be greatly reduced. In particular, when a 1-bit ADC is used, gain adjustment (AGC: Automatic Gain Control) at the receiver is not necessary, which is advantageous for low power consumption.
　さらに、本願発明により、位相に基づく定包絡線変調処理を行うことにより、高精度な無線通信が実現可能となる。そのため、単に初期推定値により伝搬路を推定するだけでなく、さらに反復計算を行うことにより、より高精度に伝搬路推定を行うことが可能となる。 Furthermore, according to the present invention, high-accuracy wireless communication can be realized by performing constant envelope modulation processing based on the phase. Therefore, it is possible not only to estimate the propagation path based on the initial estimated value but also to perform the propagation path estimation with higher accuracy by further performing iterative calculation.
本願発明の実施例である無線通信システム１の概要を示すブロック図である。It is a block diagram which shows the outline | summary of the radio | wireless communications system 1 which is an Example of this invention. 図１の送信信号生成部１０の出力波形の一例を示す。An example of the output waveform of the transmission signal generation part 10 of FIG. 1 is shown. 図２の出力波形と、位相との対応関係を示す図である。It is a figure which shows the correspondence of the output waveform of FIG. 2, and a phase. 図１の推定伝搬路部７１において用いられる伝搬路インパルス応答モデルのパラメータＨe［ｉ］及びＭを示す。The parameters H e [i] and M of the channel impulse response model used in estimating the propagation path 71 of FIG. 図１の初期推定値計算回路６１の一例である初期値推定値計算回路９１の概略を示すブロック図である。FIG. 2 is a block diagram showing an outline of an initial value estimated value calculation circuit 91 which is an example of the initial estimated value calculation circuit 61 in FIG. 1. シミュレーションの対象となる無線通信システム１０１のブロック図を示す。1 shows a block diagram of a wireless communication system 101 to be simulated. 伝搬路特性の推定値を用いて最尤系列推定を行った場合のＢＥＲ特性を示す。The BER characteristic when the maximum likelihood sequence estimation is performed using the estimated value of the propagation path characteristic is shown. 複数の既知信号を用いて雑音の影響を軽減する例を示す概略ブロック図である。It is a schematic block diagram which shows the example which reduces the influence of noise using a some known signal. MIMOチャネルにおける本願発明の他の実施例である時分割多重による既知信号送信を示す概略ブロック図である。It is a schematic block diagram which shows the known signal transmission by the time division multiplexing which is another Example of this invention in a MIMO channel. MIMOチャネルにおける本願発明のさらに他の実施例である符号分割多重による既知信号送信の概念を示す図である。It is a figure which shows the concept of the known signal transmission by the code division multiplexing which is another Example of this invention in a MIMO channel. 図１０の受信部３０７1及び伝搬路特性推定部３０９1による処理に関する概略ブロック図である。It is a schematic block diagram regarding the process by the receiving part 307 1 and the propagation path characteristic estimation part 309 1 of FIG. 伝搬路特性の推定値を用いて最尤系列推定を行った場合のＢＥＲ特性を示すグラフである。It is a graph which shows the BER characteristic at the time of performing maximum likelihood sequence estimation using the estimated value of a propagation path characteristic.
　以下では、図面を参照して、本願発明の実施例について説明する。なお、本願発明は、この実施例に限定されるものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.
　図１は、本願発明の実施例である無線通信システム１の概要を示すブロック図である。無線通信システム１は、送信機３と、受信機５を備える。送信機３は、送信信号を送信する。受信機５は、送信された信号を、伝搬路７を経由して受信する。 FIG. 1 is a block diagram showing an outline of a wireless communication system 1 which is an embodiment of the present invention. The wireless communication system 1 includes a transmitter 3 and a receiver 5. The transmitter 3 transmits a transmission signal. The receiver 5 receives the transmitted signal via the propagation path 7.
　まず、送信機３の構成及び動作について説明する。送信機３は、送信系列に対応する送信信号を生成する送信信号生成部１０（本願請求項の「信号生成手段」の一例）と、送信信号の電力増幅を行う電力増幅器１３と、電力増幅器１３の出力を送信する送信アンテナ１５（本願請求項の「送信アンテナ」の一例）を備える。 First, the configuration and operation of the transmitter 3 will be described. The transmitter 3 includes a transmission signal generation unit 10 that generates a transmission signal corresponding to a transmission sequence (an example of a “signal generation unit” in the claims of the present application), a power amplifier 13 that performs power amplification of the transmission signal, and a power amplifier 13. The transmission antenna 15 (an example of “transmission antenna” in the claims of the present application) is provided.
　本実施例では、チャネル推定用の既知系列Ｘ［ｎ］は、式(1)で与えられる。ここで、ｎはシンボル番号であり、ｎ＝０，…，Ｎ－１である（Ｎはシンボル数）。また、この実施例では、Ｘ［ｎ］のとりうる値は１又は－１であるとする（本願請求項の「複数の候補値」の一例）。 In the present embodiment, the known sequence X [n] for channel estimation is given by equation (1). Here, n is a symbol number, and n = 0,..., N−1 (N is the number of symbols). Further, in this embodiment, the possible value of X [n] is 1 or −1 (an example of “a plurality of candidate values” in the claims of the present application).
　送信信号生成部１０は、定包絡線変調処理を行う定包絡線変調部１９と、定包絡線変調部１９に送信系列Ｘ［ｎ］を与える送信系列付与部１７を備える。定包絡線変調部１９は、送信系列付与部１７から与えられた送信系列に対して式(2)の差動演算を行う差動演算部２０（本願請求項の「差動演算手段」の一例）と、差動演算部２０の出力信号を、帯域制限したパルス系列に波形整形するパルス波形整形部２３と、パルス波形整形部２３の出力信号Ｓ（ｔ）に対して変調指数０．５のＦＭ変調を行うＦＭ変調部２５（本願請求項の「定包絡線変調手段」の一例）を備える。パルス波形整形部２３は、例えば、ガウス関数をインパルス応答とするフィルタを用いる。このフィルタは、ＦＭ変調出力の帯域外スペクトルを抑圧する効果を有する。 The transmission signal generation unit 10 includes a constant envelope modulation unit 19 that performs constant envelope modulation processing, and a transmission sequence provision unit 17 that gives the transmission sequence X [n] to the constant envelope modulation unit 19. The constant envelope modulation unit 19 is a differential calculation unit 20 (an example of “differential calculation means” in the claims of the present application) that performs the differential calculation of Expression (2) on the transmission sequence given from the transmission sequence adding unit 17. ), A pulse waveform shaping unit 23 that shapes the output signal of the differential operation unit 20 into a band-limited pulse sequence, and a modulation index of 0.5 with respect to the output signal S (t) of the pulse waveform shaping unit 23 An FM modulation section 25 (an example of “constant envelope modulation means” in the claims of the present application) that performs FM modulation is provided. The pulse waveform shaping unit 23 uses, for example, a filter having a Gaussian function as an impulse response. This filter has the effect of suppressing the out-of-band spectrum of the FM modulation output.
　続いて、図２及び図３を参照して、送信系列がＸ［ｎ］＝｛１，１，１，１，１，１，－１，－１｝の場合について、定包絡線変調部１９の動作を具体的に説明する。差動演算部２０が差動演算を行った後、ＦＭ変調部２５が変調指数０．５のＦＭ変調を行う場合、ＦＭ変調器２５の出力波形は、図２のような波形を得ることができる。横軸は時間であり、縦軸は振幅を示す。２つの線は、複素数表記した出力信号のＩ相とＱ相の信号を示す。この場合、受信機におけるＦＭ復調（非線形復調）は不要となる。 Subsequently, with reference to FIG. 2 and FIG. 3, the constant envelope modulation unit 19 in the case where the transmission sequence is X [n] = {1, 1, 1, 1, 1, 1, −1, −1}. The operation of will be specifically described. After the differential operation unit 20 performs the differential operation, when the FM modulation unit 25 performs FM modulation with a modulation index of 0.5, the output waveform of the FM modulator 25 may obtain a waveform as shown in FIG. it can. The horizontal axis represents time, and the vertical axis represents amplitude. Two lines indicate I-phase and Q-phase signals of the output signal expressed in complex numbers. In this case, FM demodulation (nonlinear demodulation) at the receiver is not necessary.
　図３を参照して、図２の出力波形について、位相との対応関係を説明する。本実施例で着目する位相は、０、π／２、π及び３π／２の４つである。それぞれ、位相Ａ、Ｂ、Ｃ及びＤとする。Ｘ［ｎ］の候補値１には位相Ａ及びＢが対応し、候補値－１には位相Ｃ及びＤが対応するとする（すなわち、Ｘ［ｎ］の各候補値には、予め、２つの位相が対応付けられている。）。 Referring to FIG. 3, the relationship between the output waveform of FIG. 2 and the phase will be described. There are four phases, 0, π / 2, π, and 3π / 2, to which attention is paid in this embodiment. The phases are A, B, C, and D, respectively. Assume that candidate values 1 of X [n] correspond to phases A and B, and candidate values −1 correspond to phases C and D (that is, each candidate value of X [n] Phase is associated).
　時系列ｔnのそれぞれの時刻において、送信系列１，１，１，１，１，１，－１，－１に対して、それぞれ、位相Ａ，Ｂ，Ａ，Ｂ，Ａ，Ｂ，Ｃ，Ｄが割り当てられる。図２の２つの波形及び図３の矢印は、各位相に至る区間ａ～ｈでの位相の変化を示すものである。そして、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔnの包絡線と同じ一定値とすることにより、定包絡線位相変調処理が実現される。 At each time of the time series t n , the phases A, B, A, B, A, B, C, respectively for the transmission series 1, 1, 1, 1, 1, 1, −1, −1. D is assigned. The two waveforms in FIG. 2 and the arrows in FIG. 3 show changes in phase in the sections a to h reaching each phase. At time t (t n-1 <t <t n ), the constant envelope phase modulation processing is realized by setting the envelope to the same constant value as the envelope at time t n .
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　続いて、受信機５の構成及び動作について説明する。受信機５は、送信機３から送信された送信信号を受信して信号処理を行う受信部３１と、伝搬路７の特性を推定する伝搬路特性推定部３３（本願請求項の「伝搬路特性推定手段」、「伝搬路特性推定装置」の一例）を備える。 Subsequently, the configuration and operation of the receiver 5 will be described. The receiver 5 receives a transmission signal transmitted from the transmitter 3 and performs signal processing, and a propagation path characteristic estimation section 33 that estimates the characteristics of the propagation path 7 (“propagation path characteristics” in the claims of this application). An example of “estimating means” and “propagation path characteristic estimating apparatus”.
　受信部３１は、送信機３から送信された送信信号を、伝搬路７を経由して受信する受信アンテナ３５（本願請求項の「受信アンテナ」の一例）と、アナログ処理を行うアナログ処理部３７と、アナログ処理部３７の出力を量子化する低分解能ＡＤＣ３９（本願請求項の「ＡＤ変換手段」の一例）と、量子化後の信号に対してデジタル処理を行うデジタル処理部４１を備える。 The reception unit 31 includes a reception antenna 35 that receives the transmission signal transmitted from the transmitter 3 via the propagation path 7 (an example of “reception antenna” in the claims of the present application), and an analog processing unit 37 that performs analog processing. A low-resolution ADC 39 that quantizes the output of the analog processing unit 37 (an example of “AD conversion unit” in the claims of the present application) and a digital processing unit 41 that performs digital processing on the quantized signal.
　アナログ処理部３７は、ＬＮＡ（Low　Noise　Amplifier）等を含むＲＦ部４３と、中間周波数(IF)帯に周波数変換(MIX)するＭＩＸ部４５と、帯域制限フィルタ（BPF：Band　Pass　Filter）により信号帯域外の雑音を除去するＢＰＦ部４７を備える。 The analog processing unit 37 receives signals from an RF unit 43 including an LNA (Low Noise Amplifier), a MIX unit 45 that performs frequency conversion (MIX) to an intermediate frequency (IF) band, and a band limit filter (BPF: Band Pass Filter). A BPF unit 47 for removing out-of-band noise is provided.
　低分解能ＡＤＣ３９は、低量子化ビット（例えば１ビットなど）のアナログデジタル変換をおこなうものである。ＡＤＣは、受信信号の振幅の値を量子化する。本実施例では、特に１ビットＡＤＣの場合は、位相を量子化することとなる。受信機において低分解能ＡＤＣを利用することで、受信機の回路規模を大幅に軽減することができる。また、特に１ビットＡＤＣを利用する場合には、受信器での利得調整が不要となり、低消費電力化に有利となる。 The low resolution ADC 39 performs analog-digital conversion of low quantized bits (for example, 1 bit). The ADC quantizes the amplitude value of the received signal. In this embodiment, particularly in the case of a 1-bit ADC, the phase is quantized. By using the low resolution ADC in the receiver, the circuit scale of the receiver can be greatly reduced. In particular, when a 1-bit ADC is used, gain adjustment at the receiver is not necessary, which is advantageous in reducing power consumption.
　しかし、低分解能ＡＤＣ３９において、量子化雑音が発生する。量子化雑音は、ＡＤ変換で一般的に発生する。特に、低分解能ＡＤＣでは顕著に発生する。送信信号の包絡線振幅は一定ではある。しかし、異なる経路をたどり、複数の波が到来する。そのため、受信信号の振幅は、それらが合成され、変動する。このように、量子化雑音は、振幅に顕著に発生する。よって、本願発明にあるように、位相を用いた定包絡線変調処理を行うことにより、低分解能ＡＤＣであっても、量子化雑音の発生を抑制し、高精度での通信が実現可能となる。 However, quantization noise is generated in the low resolution ADC 39. Quantization noise is generally generated by AD conversion. This is particularly noticeable in low resolution ADCs. The envelope amplitude of the transmission signal is constant. However, following different paths, multiple waves arrive. For this reason, the amplitudes of the received signals vary as they are synthesized. Thus, the quantization noise is noticeably generated in the amplitude. Therefore, as in the present invention, by performing constant envelope modulation processing using phase, even with a low resolution ADC, the generation of quantization noise can be suppressed and high-accuracy communication can be realized. .
　デジタル処理部４１は、ＩＦ帯の信号をベースバンド帯に周波数変換するデジタルＭＩＸ部４９と、デジタルＭＩＸ部４９の出力信号に対して低域通過フィルタ処理を行うＬＰＦ（Low　Pass　Filter）部５１を備える（ＬＰＦ部５１の出力が、本願請求項の「受信量子化信号」の一例である。）。 The digital processing unit 41 includes a digital MIX unit 49 that converts an IF band signal into a baseband frequency, and an LPF (Low Pass Filter) unit 51 that performs low-pass filter processing on the output signal of the digital MIX unit 49. (The output of the LPF unit 51 is an example of the “received quantized signal” in the claims of the present application).
　続いて、図４及び図５を参照して、伝搬路特性推定部３３の構成及び動作について説明する。送信系列は、伝搬路特性推定部３３が予め把握している既知系列である。伝搬路特性推定部３３では、式(3)の伝搬路インパルス応答モデル（図４参照）のパラメータＨe［ｉ］（本願請求項の「特性パラメータ」の一例）を推定する。ここで、Ｍは、伝搬路インパルス応答モデルのパス数を表す。Ｔは、シンボル周期である。 Next, the configuration and operation of the propagation path characteristic estimation unit 33 will be described with reference to FIGS. 4 and 5. The transmission sequence is a known sequence that the propagation path characteristic estimation unit 33 knows in advance. In the propagation path estimation unit 33 estimates the equation (3) Parameter H e [i] of the channel impulse response model (see FIG. 4) of (an example of "characteristic parameter" of the claims). Here, M represents the number of paths of the propagation path impulse response model. T is the symbol period.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　伝搬路特性推定部３３は、受信量子化信号に基づいてパラメータＨe［ｉ］の初期推定値を定める初期推定値計算回路６１（本願請求項の「初期推定値計算手段」の一例）と、既知系列を示す既知信号が、パラメータＨe［ｉ］により定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成部６３（本願請求項の「複製信号生成手段」の一例）と、受信量子化信号と複製信号との差を計算する誤差計算部６５（本願請求項の「誤差計算手段」の一例）と、受信量子化信号と複製信号との差を用いてパラメータＨe［ｉ］を更新して、新たなパラメータＨe (1)［ｉ］を定める推定値計算部６７（本願請求項の「推定値計算手段」の一例）を有する。複製信号生成部６３は、推定値計算部６７により更新されたパラメータＨe (1)［ｉ］を用いて、複製信号をさらに生成する。本願発明によれば、低分解能ＡＤＣであっても、量子化雑音を避け、高い精度で送受信が可能となる。そのため、伝搬路特性推定部３３において、反復計算を行うことにより、高い精度で伝搬路７の特性を推定することが可能となる。 Propagation path characteristics estimation section 33, an initial estimated value calculating circuit 61 for determining an initial estimate of the parameters H e [i] based on the received quantized signal (an example of "initial estimate calculation means" in the claims), known signal indicating a known sequence, "replication parameters H e replica signal generating unit 63 that the estimated received signal obtained through the estimation channel defined by [i] to generate a replica signal by quantizing (appended claims An example of “signal generation means”, an error calculation unit 65 for calculating a difference between the received quantized signal and the duplicate signal (an example of “error calculating means” in the claims), a received quantized signal, and a duplicate signal update the parameter H e [i] using the difference, with a new parameter H e (1) [i] estimated value calculating section 67 for determining a (an example of "estimation value calculation unit" of the claims). Replica signal generating unit 63 uses the updated by the estimation value calculation unit 67 parameter H e (1) [i] , further generates a replica signal. According to the present invention, even with a low resolution ADC, it is possible to avoid quantization noise and transmit and receive with high accuracy. Therefore, it is possible to estimate the characteristics of the propagation path 7 with high accuracy by performing iterative calculation in the propagation path characteristic estimation unit 33.
　受信量子化信号をシンボル周期でサンプリングした信号をＹ［ｎ］と表す。初期推定値計算回路６１は、Ｙ［ｎ］に対して、式(4)の相関演算を行い、初期推定値を定める。ここで、Ｎは既知シンボル数を表す。Ｌは相関器の数を表し、Ｍ≦Ｌの関係にある。パス数Ｍは、例えば、事前に十分に大きな値を与えてもよい。また、出力Ｈe［ｉ］が、ある閾値Ｔｈを超える相関器の個数をＭとしてもよい（すなわち、ある閾値Ｔｈを超える相関器の出力Ｈe［ｉ］のうち、最大のｉをＭ－１と決定してもよい）。 A signal obtained by sampling the received quantized signal at a symbol period is represented as Y [n]. The initial estimated value calculation circuit 61 performs a correlation operation of Expression (4) on Y [n] to determine an initial estimated value. Here, N represents the number of known symbols. L represents the number of correlators and has a relationship of M ≦ L. The number of passes M may be given a sufficiently large value in advance, for example. Further, the output H e [i] is the number of correlators that exceeds a certain threshold value Th may be M (i.e., of the output H e correlator exceeds a certain threshold value Th [i], the maximum of the i M- 1 may be determined).
　図５を参照して、初期推定値計算回路６１の一例を説明する。図５の初期推定値計算回路９１は、図１の初期推定計算回路６１の一例である。初期推定値計算回路９１は、Ｌ個の相関器を有する。すなわち、受信量子化信号Ｘ［ｎ］に対して信号Ｙ［ｎ＋ｉ］を乗算するＬ個の乗算器９３1，…，９３Lと、各乗算器９３1，…，９３Lの結果の平均を計算するＬ個の平均計算部９５1，…，９５Lを備える。これにより、各相関器の出力Ｈe［ｉ］を得る。 An example of the initial estimated value calculation circuit 61 will be described with reference to FIG. The initial estimated value calculation circuit 91 in FIG. 5 is an example of the initial estimated value calculation circuit 61 in FIG. The initial estimated value calculation circuit 91 has L correlators. That, L multipliers 93 1 for multiplying the signal Y [n + i] for the received quantized signal X [n], ..., and 93 L, each multiplier 93 1, ..., the average of the results of the 93 L L average calculation sections 95 1 ,..., 95 L to be calculated are provided. This gives an output H e [i] of the correlators.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　複製信号生成部６３、誤差計算部６５及び推定値計算部６７は、初期推定値計算回路６１が定めたＨe［ｉ］を初期値として、伝搬路７の特性の推定を行う。 Replica signal generating unit 63, error calculator 65 and the estimated value calculating unit 67, the H e [i] the initial estimated value calculating circuit 61 is determined as an initial value, estimates the characteristics of the propagation path 7.
　その構成及び動作の一例について説明する。複製信号生成部６３は、既知系列を示す既知信号を生成する既知信号生成部６９と、初期推定値計算回路６１が定めたＨe［ｉ］を用いて推定伝搬路とし、既知信号が推定伝搬路を経由した場合の信号を生成する推定伝搬路部７１と、推定伝搬路部７１の出力信号の量子化を行う量子化部７３と、デジタル処理を行うデジタルＭＩＸ７５及びＬＰＦ部７７を備える。既知信号生成部６９、推定伝搬路部７１、量子化部７３、デジタルＭＩＸ部７５及びＬＰＦ部７７は、それぞれ、送信機３、伝搬路７、低分解能ＡＤＣ３９、デジタルＭＩＸ部４９及びＬＰＦ部５１に対応する。そのため、複製信号生成部６３が生成する複製信号は、推定伝搬路を用いて、受信量子化信号と同様の環境を再現して得られたものといえる。 An example of the configuration and operation will be described. Replica signal generating unit 63 includes a known signal generator 69 for generating a known signal indicating a known sequence, with H e [i] the initial estimated value calculating circuit 61 is determined by the estimated channel, the known signal is estimated propagation An estimated propagation path unit 71 that generates a signal when passing through a path, a quantization unit 73 that quantizes an output signal of the estimated propagation path unit 71, and a digital MIX 75 and an LPF unit 77 that perform digital processing are provided. The known signal generation unit 69, the estimated propagation path unit 71, the quantization unit 73, the digital MIX unit 75, and the LPF unit 77 are respectively connected to the transmitter 3, the propagation path 7, the low resolution ADC 39, the digital MIX unit 49, and the LPF unit 51. Correspond. Therefore, it can be said that the duplicate signal generated by the duplicate signal generation unit 63 is obtained by reproducing the same environment as the received quantized signal using the estimated propagation path.
　誤差計算部６５は、複製信号と受信量子化信号の差を計算する。推定値計算部６７は、例えば、複製信号と受信量子化信号の平均２乗誤差（MMSE）を求め、それが最小となるチャネルのパラメータを導出する。パラメータ導出方法としては、例えば、ＬＭＳアルゴリズムに基づく反復計算法を利用することができる。式(5)は、パラメータ更新式の一例である。推定値計算部６７は、Ｗシンボル毎にパラメータを更新しながら反復計算を行う。Ｗ＝１と設定する場合は、通常のＬＭＳアルゴリズムと同じである。ここで、ｅ(l)［ｎ］は、ｌ番目の反復におけるｎ番目のシンボルの誤差値を表す。μは、ステップサイズである。複製信号生成部６３は、更新後のＨe (l+1)［ｉ］を用いて新たに複製信号を生成する。平均２乗誤差値が十分に小さくなるまで、上記の反復計算を繰り返す。 The error calculator 65 calculates the difference between the duplicate signal and the received quantized signal. For example, the estimated value calculation unit 67 obtains the mean square error (MMSE) of the duplicate signal and the received quantized signal, and derives the parameter of the channel that minimizes the error. As the parameter derivation method, for example, an iterative calculation method based on the LMS algorithm can be used. Expression (5) is an example of a parameter update expression. The estimated value calculation unit 67 performs iterative calculation while updating parameters for each W symbol. Setting W = 1 is the same as the normal LMS algorithm. Here, e (l) [n] represents the error value of the nth symbol in the lth iteration. μ is the step size. Replica signal generating unit 63 generates a new replica signal using the updated H e (l + 1) [ i]. The above iterative calculation is repeated until the mean square error value becomes sufficiently small.
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　続いて、本実施例のチャネル推定技術を利用するシミュレーション評価結果について説明する。 Subsequently, a simulation evaluation result using the channel estimation technique of this embodiment will be described.
　図６及び図７は、伝搬路特性の推定精度を評価するために計算機シミュレーションによる特性評価を示す図である。ＡＤＣの量子化ビット数は１ビットとするが２ビット以上としてもよい。ＦＭ変調における変調指数を０．５とする。等レベル６パスの準静的レイリーフェージング伝搬路を仮定する。既知信号を送信し伝搬路特性を推定した後、最尤系列推定に基づく非線形等化を行う。 6 and 7 are diagrams showing characteristic evaluation by computer simulation in order to evaluate the estimation accuracy of propagation path characteristics. The number of quantization bits of the ADC is 1 bit, but it may be 2 bits or more. The modulation index in FM modulation is set to 0.5. Assume an equi-level 6-path quasi-static Rayleigh fading channel. After transmitting a known signal and estimating propagation path characteristics, nonlinear equalization based on maximum likelihood sequence estimation is performed.
　図６は、シミュレーションの対象となる無線通信システム１０１のブロック図を示す。図６の送信機１０３、伝搬路１０７、受信機１０５、送信系列付与部１１１、差動演算部１１３、ＦＭ変調部１１５、電力増幅器１１７、送信アンテナ１１９、受信アンテナ１２１、アナログ処理部１２３、低分解能ＡＤＣ１２５、デジタル処理部１２７、伝搬路特性推定部１２９は、それぞれ、図１の送信機３、伝搬路７、受信機５、送信系列付与部１７、差動演算部２０、ＦＭ変調部２５、電力増幅器１３、送信アンテナ１５、受信アンテナ３５、アナログ処理部３７、低分解能ＡＤＣ３９、デジタル処理部４１及び伝搬路特性推定部３３に対応する。 FIG. 6 shows a block diagram of the wireless communication system 101 to be simulated. The transmitter 103, the propagation path 107, the receiver 105, the transmission sequence assigning unit 111, the differential operation unit 113, the FM modulation unit 115, the power amplifier 117, the transmission antenna 119, the reception antenna 121, the analog processing unit 123, the low processing unit of FIG. The resolution ADC 125, the digital processing unit 127, and the propagation path characteristic estimation unit 129 are respectively the transmitter 3, the propagation path 7, the receiver 5, the transmission sequence assigning unit 17, the differential operation unit 20, the FM modulation unit 25 in FIG. This corresponds to the power amplifier 13, the transmission antenna 15, the reception antenna 35, the analog processing unit 37, the low resolution ADC 39, the digital processing unit 41, and the propagation path characteristic estimation unit 33.
　さらに、無線通信システム１０１は、最尤系列推定器（等化器）１３１を備える。伝搬路１０７のインパルス応答は、パス間隔ΔＴ＝１．５Ｔ、パス数Ｋ＝６とする関数(6)で与えられる。ここで、Ｋはシミュレーションにおいて仮定している伝搬路１０７のインパルス応答のパス数である。各パスの振幅値（複素数）は平均値の等しいレイリー分布に従う確率変数とする。伝搬路特性推定部１２９におけるインパルス応答モデルは、パス間隔Ｔ，パス数Ｍ＝９の関数(4)を用いている。最尤系列推定器１３１は、伝搬路１０７の特性と送受信機の構成が既知であるとして、複数の送信信号候補から送信系列である可能性が高いものを推定するものである。最尤系列推定器１３１は、複数の送信信号候補１，…，Ｊが、それぞれ、推定伝搬路１３３1，…，１３３Jを経由し、低分解能量子化器１３５1，…，１３５Jを経由したものと受信量子化信号との誤差を誤差計算器１３７1，…，１３７Jにより計算し、その誤差が最も小さいものを選択器１３９により選択するものである。図６におけるチャネル推定は、図１のパルス波形整形部２３を用いないものであり、定包絡線信号は、式(7)で表すことができる。ここで、f(t)は、式(8)である。また、ωcは、送信信号のキャリア周波数である。 Furthermore, the wireless communication system 101 includes a maximum likelihood sequence estimator (equalizer) 131. The impulse response of the propagation path 107 is given by the function (6) in which the path interval ΔT = 1.5T and the number of paths K = 6. Here, K is the number of impulse response paths of the propagation path 107 assumed in the simulation. The amplitude value (complex number) of each path is a random variable that follows a Rayleigh distribution with the same average value. The impulse response model in the propagation path characteristic estimation unit 129 uses a function (4) with a path interval T and the number of paths M = 9. The maximum likelihood sequence estimator 131 estimates a signal having a high possibility of being a transmission sequence from a plurality of transmission signal candidates on the assumption that the characteristics of the propagation path 107 and the configuration of the transceiver are known. Maximum likelihood sequence estimator 131, a plurality of transmission signal candidates 1, ..., J, respectively, estimates the propagation path 133 1, ..., via the 133 J, low resolution quantizer 135 1, ..., via the 135 J , 137 J is calculated by the error calculator 137 1 ,..., 137 J , and the selector 139 selects the error having the smallest error. The channel estimation in FIG. 6 does not use the pulse waveform shaping unit 23 in FIG. 1, and the constant envelope signal can be expressed by Expression (7). Here, f (t) is Equation (8). Ω c is the carrier frequency of the transmission signal.
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000007
　図７は、伝搬路特性の推定値を用いて最尤系列推定を行った場合のBER特性を示す。理想的なチャネル（Ideal　Channel）は、伝搬路特性を完全に推定できた場合のBER特性を示す。相関推定器（Correlator　Estimator）は、初期推定値を用いた場合、適応フィルタ推定器（Adaptive　Filter　Estimator）は、最小２乗誤差基準に基づく推定を行った場合の特性である。相関推定器は、従来技術でも実現可能だが、誤差が大きく生じている。それに対し、適応フィルタ推定器では、伝搬路特性の推定が完全である場合とほぼ同等のBER特性が得られている。 FIG. 7 shows the BER characteristics when maximum likelihood sequence estimation is performed using the estimated channel characteristics. The ideal channel (Ideal Channel) shows the BER characteristics when the propagation path characteristics can be completely estimated. The correlation estimator (Correlator Estimator) is a characteristic when an initial estimated value is used, and the adaptive filter estimator (Adaptive Filter Estimator) is a characteristic when estimation based on the least square error criterion is performed. Although the correlation estimator can be realized by the conventional technique, a large error occurs. On the other hand, in the adaptive filter estimator, a BER characteristic almost equal to that obtained when the propagation path characteristic is completely estimated is obtained.
　なお、例えば図８にあるように、複数の既知信号を送信し、受信機のADC出力においてそれらの平均化を行うことで雑音の影響を軽減することができる。既知信号Ｘ［ｎ］，ｎ＝０，１，…，Ｎ－１がＵ回繰り返し送信された場合に、対応する受信信号を~Ｙ(u)［ｎ］とする。式(9)のように平均化を行うことで雑音を軽減できる。この信号を図１の伝搬路特性推定部３３に入力して伝搬路特性を推定する。または、式(10)の長さＮ×Ｕの繰り返し既知系列とみなして、この信号を図１の伝搬路特性推定部３３に入力して、伝搬路推定を行ってもよい。 For example, as shown in FIG. 8, it is possible to reduce the influence of noise by transmitting a plurality of known signals and averaging them at the ADC output of the receiver. When the known signal X [n], n = 0, 1,..., N−1 is repeatedly transmitted U times, the corresponding received signal is denoted as ~ Y (u) [n]. Noise can be reduced by averaging as shown in Equation (9). This signal is input to the propagation path characteristic estimation unit 33 in FIG. 1 to estimate the propagation path characteristic. Alternatively, it may be regarded as a repeated known sequence of length N × U in equation (10), and this signal may be input to the propagation path characteristic estimation unit 33 in FIG. 1 to perform propagation path estimation.
Figure JPOXMLDOC01-appb-M000008
Figure JPOXMLDOC01-appb-M000008
　また、伝搬路特性推定部３３は、式(3)のフーリエ変換対である周波数伝達特性を伝搬路モデルとして定義し、そのパラメータを求めてもよい。さらに、推定値計算部６７は、RLSアルゴリズムなどのその他の手法を用いても良い。 Further, the propagation path characteristic estimation unit 33 may define a frequency transfer characteristic that is a Fourier transform pair of Expression (3) as a propagation path model and obtain parameters thereof. Furthermore, the estimated value calculation unit 67 may use other methods such as an RLS algorithm.
　続いて、図９を参照して、MIMOチャネルにおける本願発明の他の実施例について、説明する。MIMO伝搬路の特性を推定する場合は、例えば、複数の既知信号を時分割多重（TDM：Time　Division　Multiplexing）送信する。 Subsequently, another embodiment of the present invention in the MIMO channel will be described with reference to FIG. When estimating the characteristics of the MIMO propagation path, for example, a plurality of known signals are transmitted in time division multiplexing (TDM).
　図９は、MIMOチャネルにおける本願発明のチャネル推定技術を用いたMIMO無線通信システムの一例を示すブロック図である。MIMOシステムにおける送信アンテナ本数は２、受信アンテナ本数を２とする。なお、送信アンテナ数Ｎtxと受信アンテナ数Ｎrxはそれぞれ１以上の任意の値としてよい。送信アンテナ数は、受信アンテナ数より多くてもよく（Ｎtx＞Ｎrx）、受信アンテナ数より少なくしてもよい（Ｎtx＜Ｎrx）。 FIG. 9 is a block diagram showing an example of a MIMO wireless communication system using the channel estimation technique of the present invention in a MIMO channel. In the MIMO system, the number of transmission antennas is 2, and the number of reception antennas is 2. The number of transmission antennas N tx and the number of reception antennas N rx may each be an arbitrary value of 1 or more. The number of transmission antennas may be larger than the number of reception antennas (N tx > N rx ), or may be smaller than the number of reception antennas (N tx <N rx ).
　MIMO送信機２１５では、異なる送信系列Ａ，ＢをMIMO伝搬路２１６に送信する。送信系列Ａ、Ｂは、それぞれ異なる伝搬路を介して受信点に到来する。受信アンテナ１では、伝搬路１１を通過した送信信号Ａと伝搬路２１を通過した送信信号Ｂの合成波が受信される。一方、受信アンテナ２では、伝搬路１２を通過した送信信号Ａと伝搬路２２を通過した送信信号Ｂの合成波が受信される。直交関係にある既知信号を伝搬路１１，１２，２１，２２に送信することで、伝搬路特性推定部２２５1において伝搬路１１，２１を推定し、伝搬路特性推定部２２５2において伝搬路１２，２２を推定する。送信アンテナと受信アンテナの本数が３本以上である場合も同様である。 The MIMO transmitter 215 transmits different transmission sequences A and B to the MIMO propagation path 216. Transmission sequences A and B arrive at the reception point via different propagation paths. The reception antenna 1 receives a composite wave of the transmission signal A that has passed through the propagation path 11 and the transmission signal B that has passed through the propagation path 21. On the other hand, the reception antenna 2 receives a composite wave of the transmission signal A that has passed through the propagation path 12 and the transmission signal B that has passed through the propagation path 22. By transmitting known signals having an orthogonal relationship to the propagation paths 11, 12, 21, and 22, the propagation path characteristics estimation unit 225 1 estimates the propagation paths 11 and 21, and the propagation path characteristic estimation unit 225 2 performs propagation path 12. , 22 is estimated. The same applies when the number of transmitting antennas and receiving antennas is three or more.
　MIMO最尤系列推定器２２２は、MIMO伝搬路２１６の特性と送受信機２１５，２２１の構成が既知であるとして、複数の送信信号候補から送信系列である可能性の高いものを推定する。送信信号Ａの候補を１，２，…，Ｊ1とし、送信信号Ｂの候補を１，２，…，Ｊ2とするときの送信信号Ａ，Ｂの候補の組み合わせ総数をＱとする。Ｑ個の候補信号がそれぞれMIMO推定伝搬路２２６1,…,２２６Qを経由する。誤差計算部２２８1，…，２２８Qが低分解能量子化器２２７1，…，２２７Qを経由したものと受信信号との誤差を計算する。選択器２２９が、誤差が最も小さい送信信号ＡとＢの組み合わせを選択する。 MIMO maximum likelihood sequence estimator 222 assumes that the characteristics of MIMO propagation path 216 and the configurations of transceivers 215 and 221 are known, and estimates a transmission sequence that is highly likely to be a transmission sequence from a plurality of transmission signal candidates. , J 1 is the candidate for the transmission signal A, and Q is the total number of combinations of the candidates for the transmission signals A and B when the candidates for the transmission signal B are 1, 2 ,. Q-number of candidate signals MIMO estimated channel 226 1, respectively, ..., via the 226 Q. Error calculator 228 1, ..., 228 Q low resolution quantizer 227 1, ..., calculates an error between the received signal and that through 227 Q. The selector 229 selects the combination of the transmission signals A and B with the smallest error.
　続いて、図１０～１２を参照して、MIMOチャネルにおける本願発明のさらに他の実施例について、説明する。本実施例では、符号分割多重（CDM：Code　Division　Multiplexing）送信の場合についてである。本願発明は、複数の既知信号が直交関係にある送信方法を用いることができる。 Subsequently, still another embodiment of the present invention in the MIMO channel will be described with reference to FIGS. In the present embodiment, the case of code division multiplexing (CDM) transmission will be described. The present invention can use a transmission method in which a plurality of known signals are orthogonally related.
　図１０は、符号分割多重による既知信号送信の概念を示す図である。送信機３０１の２つの送信アンテナからは、送信系列Ａ及びＢに基づき生成された既知信号３０３1及び３０３2が送出される。本実施例では、既知信号３０３1及び３０３2は、互いに直交する関係にある符号である。これは、例えば、巡回シフトされたＭ系列を用いることができる。巡回シフトされた系列とは、最後の要素の次の要素として、先頭の要素を指すようにして、シフトを行った系列である。例えば、系列Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆに対して巡回シフトを行うことにより、Ｅ，Ｆ，Ａ，Ｂ，Ｃ，Ｄとするものである。そして、受信部３０７1及び３０７2の受信アンテナは、それぞれ、MIMO伝搬路を経由した送信信号を受信する。そして、各受信信号に対して、受信部３０７1及び３０７2並びに伝搬路特性推定器３０９1及び３０９2が処理を行う。 FIG. 10 is a diagram illustrating the concept of known signal transmission by code division multiplexing. Two transmission antennas of the transmitter 301, the transmission sequence A and the known signal 303 1 and 303 2 which are generated based on the B is delivered. In this embodiment, the known signals 303 1 and 303 2 is a code which is in relation orthogonal to each other. For example, a cyclically shifted M sequence can be used. The cyclically shifted sequence is a sequence that has been shifted so as to point to the first element as the next element after the last element. For example, E, F, A, B, C, and D are obtained by performing cyclic shift on the series A, B, C, D, E, and F. Then, the reception antennas of the reception units 307 1 and 307 2 each receive a transmission signal that has passed through the MIMO propagation path. Then, the receiving units 307 1 and 307 2 and the propagation path characteristic estimators 309 1 and 309 2 perform processing on each received signal.
　図１１は、図１０の受信部３０７1及び伝搬路特性推定部３０９1による処理に関する概略ブロック図である。図１０の受信部３０７2及び伝搬路特性推定部３０９2による処理についても、同様に実現することができる。 FIG. 11 is a schematic block diagram relating to processing by the reception unit 307 1 and the propagation path characteristic estimation unit 309 1 of FIG. The processing by the reception unit 307 2 and the propagation path characteristic estimation unit 309 2 in FIG. 10 can be similarly realized.
　図１１において、MIMO送信器３１０の構成は、図９のMIMO送信器２１５と同じである。図９の既知系列Ａ及びＢに対して、それぞれ、図１０の既知信号３０３1及び３０３2が生成される。受信器３３２は、受信部３０７1と、伝搬路特性推定部３０９1を備える。受信部３０７1の構成は、図１の受信部３１と同じである。 In FIG. 11, the configuration of the MIMO transmitter 310 is the same as that of the MIMO transmitter 215 of FIG. For the known sequences A and B in FIG. 9, the known signals 303 1 and 303 2 in FIG. 10 are generated, respectively. The receiver 332 includes a receiving unit 307 1 and a propagation path characteristic estimating unit 309 1 . Configuration of the receiving unit 307 1 is the same as the receiver 31 of FIG. 1.
　伝搬路特性推定部３０９1は、初期推定値計算回路３５１と、複製信号生成部３５３と、誤差計算部３５５と、推定値計算部３５７を備える。初期値推定値計算回路３５１は、図１の初期値推定値計算回路６１と同じである。 The propagation path characteristic estimation unit 309 1 includes an initial estimated value calculation circuit 351, a duplicate signal generation unit 353, an error calculation unit 355, and an estimated value calculation unit 357. The initial value estimated value calculation circuit 351 is the same as the initial value estimated value calculation circuit 61 of FIG.
　複製信号生成部３５３は、既知信号生成部３５９1及び３５９2と、推定伝搬路部３６１1及び３６１2と、加算器３６３と、量子化部３６５と、デジタルＭＩＸ部３６７と、ＬＰＦ部３６９を備える。量子化部３６５、デジタルＭＩＸ部３６７及びＬＰＦ部３６９は、それぞれ、図１の量子化部７３、デジタルＭＩＸ部７５及びＬＰＦ部７７と同じである。 The duplicate signal generation unit 353 includes known signal generation units 359 1 and 359 2 , estimated propagation path units 361 1 and 361 2 , an adder 363, a quantization unit 365, a digital MIX unit 367, and an LPF unit 369. Prepare. The quantization unit 365, the digital MIX unit 367, and the LPF unit 369 are the same as the quantization unit 73, the digital MIX unit 75, and the LPF unit 77 of FIG. 1, respectively.
　既知信号生成部３５９1は、既知系列Ａを示す既知信号を生成する。推定伝搬路部３６１1は、図５におけるＹ［ｎ］が既知系列Ａである場合に初期推定値計算回路３５１が定めたＨe11［ｉ］を用いて推定伝搬路とし、既知信号生成部３５９1が生成した既知信号が推定伝搬路１１（すなわち、MIMO送信器の第１アンテナから受信器の第１アンテナへの推定伝搬路）を経由した場合の信号を生成する。既知信号生成部３５９2は、既知系列Ｂを示す既知信号を生成する。推定伝搬路部３６１2も、同様に、図５におけるＹ［ｎ］が既知系列Ｂである場合に初期推定値計算回路３５１が定めたＨe21［ｉ］を用いて推定伝搬路とし、既知信号が推定伝搬路２１（すなわち、MIMO送信器の第２アンテナから受信器の第１アンテナへの推定伝搬路）を経由した場合の信号を生成する。加算器３６３は、推定伝搬路部３６１1及び３６１2が生成した信号を加算する。量子化部３６５、デジタルＭＩＸ部３６７及びＬＰＦ部３６９は、加算器３６３の信号に対して、図１と同じ処理を行う。よって、複製信号生成部３５３が生成する複製信号は、推定伝搬路を用いて、受信量子化信号と同様の環境を再現して得られたものといえる。 The known signal generator 359 1 generates a known signal indicating the known sequence A. The estimated propagation path unit 361 1 uses He 11 [i] determined by the initial estimated value calculation circuit 351 when Y [n] in FIG. A signal is generated when the known signal generated by 1 passes through the estimated propagation path 11 (that is, the estimated propagation path from the first antenna of the MIMO transmitter to the first antenna of the receiver). The known signal generation unit 359 2 generates a known signal indicating the known sequence B. Similarly, when Y [n] in FIG. 5 is a known sequence B, the estimated propagation path unit 361 2 is also set as an estimated propagation path using He 21 [i] determined by the initial estimated value calculation circuit 351, and the known signal Generates a signal when passing through the estimated propagation path 21 (that is, the estimated propagation path from the second antenna of the MIMO transmitter to the first antenna of the receiver). The adder 363 adds the signals generated by the estimated propagation path units 361 1 and 361 2 . The quantization unit 365, the digital MIX unit 367, and the LPF unit 369 perform the same processing as that in FIG. Therefore, it can be said that the duplicate signal generated by duplicate signal generator 353 is obtained by reproducing the same environment as the received quantized signal using the estimated propagation path.
　誤差計算部３５５は、複製信号と受信量子化信号の差を計算する。推定値計算部３５７は、例えば、複製信号と受信量子化信号の平均２乗誤差（MMSE）を求め、それが最小となるチャネルのパラメータを導出する。パラメータ導出方法としては、例えば、ＬＭＳアルゴリズムに基づく反復計算法を利用することができる。式(12)(13)は、パラメータ更新式の一例である。推定値計算部３５７は、Ｗシンボル毎にパラメータを更新しながら反復計算を行う。Ｗ＝１と設定する場合は、通常のＬＭＳアルゴリズムと同じである。ここで、ｅ11 (l)［ｎ］およびｅ21 (l)［ｎ］は、ｌ番目の反復におけるｎ番目のシンボルの誤差値を表す。μは、ステップサイズである。複製信号生成部３５３は、更新後のＨe11 (l+1)［ｉ］とＨe21 (l+1)［ｉ］を用いて新たに複製信号を生成する。平均２乗誤差値が十分に小さくなるまで、上記の反復計算を繰り返す。 The error calculator 355 calculates the difference between the duplicate signal and the received quantized signal. For example, the estimated value calculation unit 357 obtains the mean square error (MMSE) of the duplicate signal and the received quantized signal, and derives the parameter of the channel that minimizes the error. As the parameter derivation method, for example, an iterative calculation method based on the LMS algorithm can be used. Expressions (12) and (13) are examples of parameter update expressions. The estimated value calculation unit 357 performs iterative calculation while updating the parameter for each W symbol. Setting W = 1 is the same as the normal LMS algorithm. Here, e 11 (l) [n] and e 21 (l) [n] represent the error value of the nth symbol in the lth iteration. μ is the step size. The duplicate signal generation unit 353 newly generates a duplicate signal using the updated He 11 (l + 1) [i] and He 21 (l + 1) [i]. The above iterative calculation is repeated until the mean square error value becomes sufficiently small.
Figure JPOXMLDOC01-appb-M000009
Figure JPOXMLDOC01-appb-M000009
　続いて、本実施例のチャネル推定技術を利用するシミュレーション評価結果について説明する。図１２は、伝搬路特性の推定値を用いて最尤系列推定を行った場合のＢＥＲ特性を示すグラフである。横軸は、Ｅb/Ｎ0（ｄＢ）であり、縦軸は、ＢＥＲを示す。「理想的なチャネル」は、四角形のラインで示され、伝搬路特性を完全に推定できた場合のBER特性を示す。「CDM信号を用いるチャネル推定」は、三角形のラインで示され、CDMにより既知信号の送信を行い伝搬路特性の推定を行う場合のBER特性である。「TDM信号を用いるチャネル推定」は、丸のラインで示され、TDMにより既知信号の送信を行い伝搬路特性の推定を行う場合のBER特性である。ＡＤＣの量子化ビット数は１ビットとするが２ビット以上としてもよい。ＦＭ変調における変調指数を０．５とする。等レベル４パスの準静的レイリーフェージング伝搬路を仮定する。既知信号を送信し伝搬路特性を推定した後、最尤系列推定に基づく非線形等化を行う。送受信のアンテナ本数はそれぞれ２本とする。CDMでは、伝搬路特性の推定が完全である場合とほぼ同等のBER特性が得られている。 Subsequently, a simulation evaluation result using the channel estimation technique of this embodiment will be described. FIG. 12 is a graph showing the BER characteristic when maximum likelihood sequence estimation is performed using the estimated channel characteristic value. The horizontal axis represents E b / N 0 (dB), and the vertical axis represents BER. The “ideal channel” is indicated by a square line and indicates the BER characteristic when the propagation path characteristic can be completely estimated. “Channel estimation using CDM signal” is indicated by a triangular line, and is a BER characteristic when a known signal is transmitted by CDM and a propagation path characteristic is estimated. “Channel estimation using a TDM signal” is a BER characteristic when a known signal is transmitted by TDM to estimate a propagation path characteristic. The number of quantization bits of the ADC is 1 bit, but it may be 2 bits or more. The modulation index in FM modulation is set to 0.5. Assume an equi-level 4-path quasi-static Rayleigh fading channel. After transmitting a known signal and estimating propagation path characteristics, nonlinear equalization based on maximum likelihood sequence estimation is performed. The number of antennas for transmission and reception is two. In CDM, a BER characteristic almost equivalent to that obtained when the propagation path characteristic is completely estimated is obtained.
　１，１０１　無線通信システム、３，１０３　送信機、５，１０５　受信機、７，１０７　伝搬路、１０　送信信号生成部、１３，１１７　電力増幅器、１５，１１９　送信アンテナ、１７，１１１　送信系列付与部、２０，１１３　差動演算部、２３　パルス波形整形部、２５，１１５　ＦＭ変調部、３１，３０７　受信部、３３，１２９，２２５，３０９　伝搬路特性推定部、３５，１２１　受信アンテナ、３７，１２３　アナログ処理部、３９，１２５　低分解能ＡＤＣ、４１，１２７　デジタル処理部、４３　ＲＦ部、４５　ＭＩＸ部、４７　ＢＰＦ部、４９　デジタルＭＩＸ部、５１　ＬＰＦ部、６１，３５１　初期推定値計算回路、６３，３５３　複製信号生成部、６５，３５５　誤差計算部、６７，３５７　推定値計算部、６９，３５９　既知信号生成部、７１，３６１　推定伝搬路部、７３，３６５　量子化部、７５，３６７　デジタルＭＩＸ部、７７，３６９　ＬＰＦ部、１３３　推定伝搬路、１３５，２２７　低分解能量子化、１３７，２２８　誤差計算、１３０，２２９　選択器、２１５，３０１　MIMO送信器、２１６　MIMO伝搬路、２２１　MIMO受信器、２２６　MIMO推定伝搬路 1,101 wireless communication system, 3,103 transmitter, 5,105 receiver, 7,107 propagation path, 10, transmission signal generation unit, 13,117 power amplifier, 15,119 transmission antenna, 17,111 transmission sequence assignment unit 20, 113 differential operation unit, 23 pulse waveform shaping unit, 25, 115 FM modulation unit, 31,307 reception unit, 33, 129, 225, 309 propagation path characteristic estimation unit, 35, 121 reception antenna, 37, 123 Analog processing unit, 39, 125 low resolution ADC, 41, 127 digital processing unit, 43 RF unit, 45 MIX unit, 47 BPF unit, 49 digital MIX unit, 51 LPF unit, 61, 351 initial estimated value calculation circuit, 63, 353 Duplicate signal generator, 65, 355 error calculator, 67, 357 estimated value calculator, 9,359, known signal generator, 71,361 estimated propagation path, 73,365 quantization, 75,367 digital MIX, 77,369 LPF, 133 estimated propagation, 135,227 low resolution quantization, 137 , 228 error calculation, 130,229 selector, 215,301 MIMO transmitter, 216 MIMO propagation path, 221 MIMO receiver, 226 MIMO estimation propagation path

Claims (9)

  1. 　送信機と受信機を備えた無線通信システムであって、
    　前記送信機は、前記受信機に対して、送信系列Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）に対応する送信信号を無線通信により送信するものであり、
    　前記送信系列の各値Ｘ［ｎ］は、複数の候補値の一つであり、
    　前記各候補値には、予め、一つ又は複数の位相が対応付けられており、
    　前記送信機は、
    　　位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、
    　　前記送信信号を前記受信機に対して送信する送信アンテナを有し、
    　前記信号生成手段は、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時系列ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行うものであり、
    　前記受信機は、
    　　前記送信アンテナから送信された前記送信信号を、伝搬路を経由して受信する受信アンテナと、
    　　前記受信アンテナにおいて受信された受信信号を量子化して受信量子化信号を生成するＡＤ変換手段を有する、無線通信システム。     A wireless communication system comprising a transmitter and a receiver,
    The transmitter transmits a transmission signal corresponding to a transmission sequence X [n] (n = 0,..., N−1, N is the number of symbols) to the receiver by wireless communication.
    Each value X [n] of the transmission sequence is one of a plurality of candidate values,
    Each candidate value is associated with one or more phases in advance,
    The transmitter is
    Signal generating means for generating the transmission signal by performing constant envelope modulation processing based on the phase;
    A transmission antenna for transmitting the transmission signal to the receiver;
    It said signal generating means, the time series t relative to n, and one phase associated with each value X [n] at each time t n in the transmission sequence, the time t (t n-1 <t < In t n ), the constant envelope modulation process is performed by making the envelope constant at the same value as the envelope of the time series t n-1 or t n ,
    The receiver
    A reception antenna that receives the transmission signal transmitted from the transmission antenna via a propagation path;
    A wireless communication system comprising AD conversion means for quantizing a reception signal received at the reception antenna to generate a reception quantized signal.
  2. 　前記送信系列は、前記送信機及び前記受信機が予め把握している既知系列であり、
    　前記受信機は、前記伝搬路の特性を推定する伝搬路特性推定手段を有し、
    　前記伝搬路特性推定手段は、
    　　前記受信量子化信号に基づいて、前記伝搬路の特性を示す特性パラメータの初期推定値を定める初期推定値計算手段と、
    　　前記既知系列を示す既知信号が、前記特性パラメータにより定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成手段と、
    　　前記受信量子化信号と前記複製信号との差を計算する誤差計算手段と、
    　　前記受信量子化信号と前記複製信号との差を用いて前記特性パラメータを更新する推定値計算手段を有し、
    　前記複製信号生成手段は、前記推定値計算手段により更新された前記特性パラメータを用いて、前記複製信号をさらに生成する、請求項１記載の無線通信システム。     The transmission sequence is a known sequence that is known in advance by the transmitter and the receiver,
    The receiver has propagation path characteristic estimation means for estimating the characteristics of the propagation path,
    The propagation path characteristic estimation means includes
    An initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path based on the received quantized signal;
    A replicated signal generating means for generating a replicated signal by quantizing an estimated received signal obtained by the known signal indicating the known sequence via an estimated propagation path determined by the characteristic parameter;
    Error calculating means for calculating a difference between the received quantized signal and the duplicate signal;
    An estimated value calculating means for updating the characteristic parameter using a difference between the received quantized signal and the duplicate signal;
    The wireless communication system according to claim 1, wherein the duplicate signal generating means further generates the duplicate signal using the characteristic parameter updated by the estimated value calculating means.
  3. 　前記初期推定値計算手段は、Ｌ個の相関器を有し、
    　　前記Ｌ個の相関器のうち、所定の閾値を超える相関器の出力の個数Ｍをパス数として推定し、
    　　前記受信量子化信号をシンボル周期でサンプリングした信号Ｙ［ｎ］に対して、相関演算を行うことにより、前記特性パラメータの初期推定値を定めるものであり、
    　前記伝搬路特性推定手段が、パス数Ｍ及び初期推定値、並びに、前記誤差計算手段により得られた前記受信量子化信号と前記複製信号との差に基づいて前記特性パラメータを更新するものである、請求項２記載の無線通信システム。     The initial estimated value calculation means has L correlators,
    Among the L correlators, the number M of correlator outputs exceeding a predetermined threshold is estimated as the number of paths,
    An initial estimated value of the characteristic parameter is determined by performing a correlation operation on the signal Y [n] obtained by sampling the received quantized signal at a symbol period;
    The propagation path characteristic estimation means updates the characteristic parameter based on the number of paths M and the initial estimated value, and the difference between the received quantized signal and the duplicate signal obtained by the error calculation means. The wireless communication system according to claim 2.
  4. 　前記信号生成手段は、
    　　前記送信系列に対して差動演算を行う差動演算手段と、
    　　前記差動演算手段の演算結果を示す差動演算信号に対して定包絡線変調を行う定包絡線変調手段を有する、請求項２又は３記載の無線通信システム。     The signal generating means includes
    Differential operation means for performing a differential operation on the transmission series;
    The radio | wireless communications system of Claim 2 or 3 which has a constant envelope modulation means which performs constant envelope modulation with respect to the differential calculation signal which shows the calculation result of the said differential calculation means.
  5. 　前記送信系列の各値Ｘ［ｎ］が候補値は、２つの値のいずれかであり、
    　前記差動演算部は、ｎの奇偶に応じて式(eq1)又は式(eq2)のいずれかを行う差動演算を行うものであり、
    　前記定包絡線変調手段は、変調指数０．５のＦＭ変調を行うものであり、
    　前記ＡＤ変換手段は、前記受信信号の振幅の値と一定の値を比較して、前記候補値のいずれかに対応付けることにより、量子化を行う１ビット・アナログデジタル変換処理を行うものである、請求項４記載の無線通信システム。
    Figure JPOXMLDOC01-appb-M000001
         Each value X [n] of the transmission sequence is one of two values,
    The differential operation unit performs a differential operation to perform either of the equations (eq1) or (eq2) according to the odd / even number of n,
    The constant envelope modulation means performs FM modulation with a modulation index of 0.5,
    The AD conversion means performs a 1-bit analog-digital conversion process for performing quantization by comparing the value of the amplitude of the received signal with a certain value and associating it with one of the candidate values. The wireless communication system according to claim 4.
    Figure JPOXMLDOC01-appb-M000001
  6. 　受信機に対して、送信系列Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）に対応する送信信号を無線通信により送信する送信機であって、
    　前記送信系列の各値Ｘ［ｎ］は、複数の候補値の一つであり、
    　前記各候補値には、予め、一つ又は複数の位相が対応付けられており、
    　前記受信機は、
    　　前記送信機から送信された前記送信信号を受信する受信アンテナと、
    　　前記受信アンテナにおいて受信された受信信号を量子化するＡＤ変換手段を有するものであり、
    　位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、
    　前記送信信号を前記受信機に対して送信する送信アンテナを有し、
    　前記信号生成手段が、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行う、送信機。     A transmitter for transmitting a transmission signal corresponding to a transmission sequence X [n] (n = 0,..., N−1, N is the number of symbols) to a receiver by wireless communication,
    Each value X [n] of the transmission sequence is one of a plurality of candidate values,
    Each candidate value is associated with one or more phases in advance,
    The receiver
    A receiving antenna for receiving the transmission signal transmitted from the transmitter;
    Comprising AD conversion means for quantizing the received signal received at the receiving antenna;
    Signal generating means for generating the transmission signal by performing constant envelope modulation processing based on the phase;
    A transmission antenna for transmitting the transmission signal to the receiver;
    Said signal generating means, when the relative sequence t n, as one phase associated with each value X [n] at each time t n in the transmission sequence, the time t (t n-1 <t < In t n ), the transmitter performs the constant envelope modulation processing by making the envelope constant at the same value as the envelope at time t n−1 or t n .
  7. 　送信機が送信系列に基づいて生成して無線送信し、受信機が受信して得られた受信信号を用いて伝搬路の特性を推定する伝搬路特性推定装置であって、
    　前記送信系列の各値Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）は、複数の候補値の一つであり、
    　前記各候補値には、予め、一つ又は複数の位相が対応付けられており、
    　前記送信系列は、前記送信機及び前記受信機が予め把握している既知系列であり、
    　前記送信機は、
    　　位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、
    　　前記送信信号を前記受信機に対して送信する送信アンテナを有するものであり、
    　前記信号生成手段は、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行うものであり、
    　前記受信機は、
    　　前記送信アンテナから送信された前記送信信号を、伝搬路を経由して受信する受信アンテナと、
    　　前記受信アンテナにおいて受信された受信信号を量子化して受信量子化信号を生成するＡＤ変換手段を有するものであり、
    　前記受信量子化信号に基づいて、前記伝搬路の特性を示す特性パラメータの初期推定値を定める初期推定値計算手段と、
    　前記既知系列を示す既知信号が、前記特性パラメータにより定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成手段と、
    　前記受信量子化信号と前記複製信号との差を計算する誤差計算手段と、
    　前記誤差計算手段により得られた前記受信量子化信号と前記複製信号との差を用いて前記特性パラメータを更新する推定値計算手段を有し、
    　前記複製信号生成手段は、前記推定値計算手段により更新された前記特性パラメータを用いて、前記複製信号をさらに生成する、伝搬路特性推定装置。     A propagation path characteristic estimation device that estimates a propagation path characteristic using a received signal obtained by a transmitter generated based on a transmission sequence and wirelessly transmitted and received by a receiver,
    Each value X [n] (n = 0,..., N−1, N is the number of symbols) of the transmission sequence is one of a plurality of candidate values,
    Each candidate value is associated with one or more phases in advance,
    The transmission sequence is a known sequence that is known in advance by the transmitter and the receiver,
    The transmitter is
    Signal generating means for generating the transmission signal by performing constant envelope modulation processing based on the phase;
    A transmission antenna for transmitting the transmission signal to the receiver;
    It said signal generating means, the time series t relative to n, and one phase associated with each value X [n] at each time t n in the transmission sequence, the time t (t n-1 <t < In t n ), the constant envelope modulation process is performed by making the envelope constant at the same value as the envelope at time t n−1 or t n ,
    The receiver
    A reception antenna that receives the transmission signal transmitted from the transmission antenna via a propagation path;
    Comprising AD conversion means for quantizing a reception signal received at the reception antenna to generate a reception quantized signal;
    An initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path based on the received quantized signal;
    A replicated signal generating means for generating a replicated signal by quantizing an estimated received signal obtained by the known signal indicating the known sequence via an estimated propagation path determined by the characteristic parameter;
    Error calculating means for calculating a difference between the received quantized signal and the duplicate signal;
    An estimated value calculating means for updating the characteristic parameter using a difference between the received quantized signal and the duplicate signal obtained by the error calculating means;
    The propagation path characteristic estimation device, wherein the duplicate signal generation means further generates the duplicate signal using the characteristic parameter updated by the estimated value calculation means.
  8. 　送信機が送信系列に基づいて生成して無線送信し、受信機が受信して得られた受信信号を用いて伝搬路の特性を推定する伝搬路特性推定方法であって、
    　前記送信系列の各値Ｘ［ｎ］（ｎ＝０，…，Ｎ－１、Ｎはシンボル数。）は、複数の候補値の一つであり、
    　前記各候補値には、予め、一つ又は複数の位相が対応付けられており、
    　前記送信系列は、前記送信機及び前記受信機が予め把握している既知系列であり、
    　前記送信機は、
    　　位相に基づいて定包絡線変調処理を行うことにより前記送信信号を生成する信号生成手段と、
    　　前記送信信号を前記受信機に対して送信する送信アンテナを有するものであり、
    　前記信号生成手段は、時系列ｔnに対して、各時刻ｔnでは前記送信系列の各値Ｘ［ｎ］に対応付けられた位相の一つとし、時刻ｔ（ｔn-1＜ｔ＜ｔn）では包絡線を時刻ｔn-1又はｔnの包絡線と同じ値で一定とすることにより、前記定包絡線変調処理を行うものであり、
    　前記受信機は、
    　　前記送信アンテナから送信された前記送信信号を、伝搬路を経由して受信する受信アンテナと、
    　　前記受信アンテナにおいて受信された受信信号を量子化して受信量子化信号を生成するＡＤ変換手段と、
    　　前記伝搬路の特性を推定する伝搬路特性推定手段を有するものであり、
    　前記伝搬路特性推定手段は、
    　　前記受信量子化信号に基づいて、前記伝搬路の特性を示す特性パラメータの初期推定値を定める初期推定値計算手段と、
    　　前記既知系列を示す既知信号が、前記特性パラメータにより定められる推定伝搬路を経由して得られる推定受信信号を量子化して複製信号を生成する複製信号生成手段と、
    　　前記受信量子化信号と前記複製信号との差を計算する誤差計算手段を有し、
    　推定値計算手段が、前記誤差計算手段により得られた前記受信量子化信号と前記複製信号との差を用いて前記特性パラメータを更新する推定値計算ステップと、
    　前記複製信号生成手段が、前記推定値計算手段により更新された前記特性パラメータを用いて、前記複製信号をさらに生成するステップを含む伝搬路特性推定方法。     A propagation path characteristic estimation method in which a transmitter generates and wirelessly transmits based on a transmission sequence, and a receiver estimates a propagation path characteristic using a received signal obtained by receiving,
    Each value X [n] (n = 0,..., N−1, N is the number of symbols) of the transmission sequence is one of a plurality of candidate values,
    Each candidate value is associated with one or more phases in advance,
    The transmission sequence is a known sequence that is known in advance by the transmitter and the receiver,
    The transmitter is
    Signal generating means for generating the transmission signal by performing constant envelope modulation processing based on the phase;
    A transmission antenna for transmitting the transmission signal to the receiver;
    It said signal generating means, the time series t relative to n, and one phase associated with each value X [n] at each time t n in the transmission sequence, the time t (t n-1 <t < In t n ), the constant envelope modulation process is performed by making the envelope constant at the same value as the envelope at time t n−1 or t n ,
    The receiver
    A reception antenna that receives the transmission signal transmitted from the transmission antenna via a propagation path;
    AD conversion means for quantizing a reception signal received at the reception antenna to generate a reception quantized signal;
    Having propagation path characteristic estimation means for estimating the characteristics of the propagation path,
    The propagation path characteristic estimation means includes
    An initial estimated value calculating means for determining an initial estimated value of a characteristic parameter indicating the characteristic of the propagation path based on the received quantized signal;
    A replicated signal generating means for generating a replicated signal by quantizing an estimated received signal obtained by the known signal indicating the known sequence via an estimated propagation path determined by the characteristic parameter;
    Error calculation means for calculating a difference between the received quantized signal and the duplicate signal;
    An estimated value calculating means for updating the characteristic parameter using a difference between the received quantized signal obtained by the error calculating means and the duplicate signal; and
    A propagation path characteristic estimation method including the step of the duplicate signal generation means further generating the duplicate signal using the characteristic parameter updated by the estimated value calculation means.
  9. 　コンピュータにおいて、請求項８記載の伝搬路特性推定方法を実現させるためのプログラム。 A program for realizing the propagation path characteristic estimation method according to claim 8 in a computer.
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JPS5834661A (en) * 1981-08-25 1983-03-01 Toshiba Corp Digital modulator
JPH05304542A (en) * 1992-04-24 1993-11-16 Sony Corp Demodulation method and demodulator
JP2009081745A (en) * 2007-09-27 2009-04-16 Kyushu Univ Transmission system, transmitter, receiver and transmission method

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JPS5834661A (en) * 1981-08-25 1983-03-01 Toshiba Corp Digital modulator
JPH05304542A (en) * 1992-04-24 1993-11-16 Sony Corp Demodulation method and demodulator
JP2009081745A (en) * 2007-09-27 2009-04-16 Kyushu Univ Transmission system, transmitter, receiver and transmission method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108712196A (en) * 2018-02-14 2018-10-26 北京交通大学 The extensive MIMO mixing pre-coding system of low resolution millimeter wave and method
CN108712196B (en) * 2018-02-14 2021-04-09 北京交通大学 Low-resolution millimeter wave large-scale MIMO hybrid precoding system and method

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