JP2020178212A

JP2020178212A - Frequency deviation detection circuit, receiver including the same, frequency deviation detection method, and frequency deviation detection program

Info

Publication number: JP2020178212A
Application number: JP2019078638A
Authority: JP
Inventors: 大輔家城; Daisuke Yashiro
Original assignee: NEC Network and Sensor Systems Ltd
Current assignee: NEC Network and Sensor Systems Ltd
Priority date: 2019-04-17
Filing date: 2019-04-17
Publication date: 2020-10-29
Anticipated expiration: 2039-04-17
Also published as: JP7283741B2

Abstract

To provide a frequency deviation detection circuit capable of detecting frequency deviation of an input signal accurately, and to provide a receiver including the same, a frequency deviation detection method, and a frequency deviation detection program.SOLUTION: A frequency deviation detection section 23 includes a transmission path response estimation part 231 performing estimation of transmission path response for each symbol by comparing a prescribed synchronous word and a synchronous word, included in an input signal received wirelessly by single carrier transmission, each symbol while sliding, a frequency deviation calculation section 232 for calculating frequency deviation of the input signal on the basis of the estimate of transmission path response, a frequency correction part 233 correcting frequency of the input signal for each symbol on the basis of the calculated value of frequency deviation, a synchronous word detection part 235 for detecting the synchronous word included in the input signal subjected to frequency correction, and a frequency holding part 236 for capturing the calculated value of frequency deviation calculated by the frequency deviation calculation section 232, in synchronism with detection timing of the synchronous word.SELECTED DRAWING: Figure 1

Description

本発明は、周波数偏差検出回路、それを備えた受信機、周波数偏差検出方法、及び、周波数偏差検出プログラムに関する。 The present invention relates to a frequency deviation detection circuit, a receiver including the same, a frequency deviation detection method, and a frequency deviation detection program.

無線通信システムにおいて、受信機は、送信機から送信された無線信号の周波数と、受信機によって受信された無線信号（受信信号）の周波数と、のずれ（周波数偏差）を検出し、そのずれを補正した後、受信信号を復調させている。そのため、受信機には、周波数偏差を精度良く検出することが求められている。 In a wireless communication system, the receiver detects a deviation (frequency deviation) between the frequency of the radio signal transmitted from the transmitter and the frequency of the radio signal (received signal) received by the receiver, and detects the deviation. After the correction, the received signal is demolished. Therefore, the receiver is required to detect the frequency deviation with high accuracy.

特許文献１には、シングルキャリア伝送における、同期ワード（ＳＷ：ＳｙｎｃｈｒｏｎｏｕｓＷｏｒｄ）を用いた周波数偏差の検出方法が開示されている。特許文献１に開示された周波数偏差検出方法は、高ＳＮ比環境下や周波数偏差が小さい場合、受信信号に含まれる同期ワードと、既知の同期ワードと、の間の強い相関関係によって、受信信号に含まれる同期ワードの位置を特定することができる。それにより、この周波数偏差検出方法は、同期ワードの伝送路応答を推定して、周波数偏差を算出することができる。なお、ＳＮ比とは、ＳｉｇｎａｌｔｏＮｏｉｓｅｒａｔｉｏの略であり、信号対雑音比のことである。 Patent Document 1 discloses a method for detecting a frequency deviation using a synchronous word (SW: Synchronous Word) in single carrier transmission. The frequency deviation detection method disclosed in Patent Document 1 is based on a strong correlation between a synchronization word included in a reception signal and a known synchronization word in a high SN ratio environment or when the frequency deviation is small. The position of the synchronization word contained in can be specified. Thereby, this frequency deviation detection method can estimate the transmission line response of the synchronous word and calculate the frequency deviation. The signal-to-noise ratio is an abbreviation for Signal to Noise ratio, and is a signal-to-noise ratio.

その他、特許文献２及び特許文献３にも、周波数偏差の検出方法が開示されている。 In addition, Patent Document 2 and Patent Document 3 also disclose a method for detecting a frequency deviation.

国際公開第２０１２／１４７３７７号International Publication No. 2012/147377 特開２０１０−７４２８４号公報JP-A-2010-74284 特開２００６−２７９６８６号公報Japanese Unexamined Patent Publication No. 2006-279686

しかしながら、特許文献１に開示された周波数偏差検出方法は、低ＳＮ比環境下や周波数偏差が大きい場合には、受信信号に含まれる同期ワードと、既知の同期ワードと、の相関が弱くなるため、受信信号に含まれる同期ワードの位置を特定することができない。そのため、特許文献１に開示された周波数偏差検出方法では、周波数偏差を精度良く検出することができないという課題があった。 However, in the frequency deviation detection method disclosed in Patent Document 1, the correlation between the synchronization word included in the received signal and the known synchronization word becomes weak in a low SN ratio environment or when the frequency deviation is large. , The position of the synchronization word included in the received signal cannot be specified. Therefore, the frequency deviation detection method disclosed in Patent Document 1 has a problem that the frequency deviation cannot be detected with high accuracy.

特にビットレート（シンボルレート）に対する搬送波の周波数が高い場合には、周波数偏差が大きくなるため、この課題は顕著になる。例えば、搬送波の周波数が１００ＭＨｚ、変調方式がＱＰＳＫ、シンボルレートが１ｋｓｙｍ／ｓ、送受信クロック偏差が１ｐｐｍ、送信機及び受信機によって遅延検波される場合、受信機における最大周波数偏差は１００（＝１＾８×１＾（−６））Ｈｚとなる。なお、ＱＰＳＫは、ＱｕａｄｒａｔｕｒｅＰｈａｓｅＳｈｉｆｔＫｅｙｉｎｇの略である。つまり、この場合、周波数偏差はシンボルレートの１０％となる。これは、コンスタレーション点の位相が１０％（３６°）回転してしまうことを意味している。それにより、変調次数が高くなるほど、変調エラー率（ＭＥＲ：ＭｏｄｕｌａｔｉｏｎＥｒｒｏｒＲａｔｉｏ）が上昇してしまう。 In particular, when the frequency of the carrier wave with respect to the bit rate (symbol rate) is high, the frequency deviation becomes large, so this problem becomes remarkable. For example, when the carrier frequency is 100 MHz, the modulation method is QPSK, the symbol rate is 1 ksym / s, the transmission / reception clock deviation is 1 ppm, and delay detection is performed by the transmitter and receiver, the maximum frequency deviation in the receiver is 100 (= 1 ^). It becomes 8 × 1 ^ (-6)) Hz. QPSK is an abbreviation for Quadrature Phase Shift Keying. That is, in this case, the frequency deviation is 10% of the symbol rate. This means that the phase of the constellation point is rotated by 10% (36 °). As a result, the higher the modulation order, the higher the modulation error rate (MER: Modulation Error Ratio).

本開示の目的は、上述した課題を解決する周波数偏差検出回路、それを備えた受信機、周波数偏差検出方法、及び、周波数偏差検出プログラムを提供することにある。 An object of the present disclosure is to provide a frequency deviation detection circuit for solving the above-mentioned problems, a receiver provided with the same, a frequency deviation detection method, and a frequency deviation detection program.

一実施の形態によれば、周波数偏差検出回路は、予め取得されている所定の同期ワードと、シングルキャリア伝送によって無線受信された受信信号に含まれる、前記所定の同期ワードに対応する同期ワードと、をスライドさせながらシンボル毎に比較することにより、シンボル毎に伝送路応答の推定を行う伝送路応答推定部と、前記伝送路応答推定部によって推定された前記伝送路応答の推定値に基づいて、前記受信信号の周波数偏差を算出する周波数偏差算出部と、前記周波数偏差算出部によって算出された前記周波数偏差の算出値に基づいて、シンボル毎に前記受信信号の周波数を補正する第１周波数補正部と、前記第１周波数補正部によって周波数補正された前記受信信号に含まれる前記同期ワードと、前記所定の同期ワードと、の間の相関関係から、前記受信信号に含まれる前記同期ワードを検出する同期ワード検出部と、前記同期ワード検出部によって前記同期ワードが検出されたタイミングに同期して、前記周波数偏差算出部によって算出された前記周波数偏差の算出値を取り込んで出力する周波数保持部と、を備える。 According to one embodiment, the frequency deviation detection circuit includes a predetermined synchronization word acquired in advance and a synchronization word corresponding to the predetermined synchronization word included in the received signal wirelessly received by the single carrier transmission. Based on the transmission line response estimation unit that estimates the transmission line response for each symbol and the transmission line response estimation value estimated by the transmission line response estimation unit by comparing each symbol while sliding. First frequency correction that corrects the frequency of the received signal for each symbol based on the frequency deviation calculation unit that calculates the frequency deviation of the received signal and the calculated value of the frequency deviation calculated by the frequency deviation calculation unit. The synchronization word included in the reception signal is detected from the correlation between the unit, the synchronization word included in the reception signal frequency-corrected by the first frequency correction unit, and the predetermined synchronization word. A synchronization word detection unit and a frequency holding unit that captures and outputs the calculated value of the frequency deviation calculated by the frequency deviation calculation unit in synchronization with the timing at which the synchronization word is detected by the synchronization word detection unit. , Equipped with.

一実施の形態によれば、周波数偏差検出方法は、予め取得されている所定の同期ワードと、シングルキャリア伝送によって無線受信された受信信号に含まれる、前記所定の同期ワードに対応する同期ワードと、をスライドさせながらシンボル毎に比較することにより、シンボル毎に伝送路応答の推定を行う伝送路応答推定ステップと、推定された前記伝送路応答の推定値に基づいて、前記受信信号の周波数偏差を算出する周波数偏差算出ステップと、算出された前記周波数偏差の算出値に基づいて、シンボル毎に前記受信信号の周波数を補正する周波数補正ステップと、周波数補正された前記受信信号に含まれる前記同期ワードと、前記所定の同期ワードと、の間の相関関係から、前記受信信号に含まれる前記同期ワードを検出する同期ワード検出ステップと、前記同期ワードが検出されたタイミングに同期して、周波数偏差算出ステップにおいて算出された前記周波数偏差の算出値を取り込んで出力する周波数偏差出力ステップと、を備える。 According to one embodiment, the frequency deviation detection method includes a predetermined synchronization word acquired in advance and a synchronization word corresponding to the predetermined synchronization word included in the received signal wirelessly received by the single carrier transmission. The frequency deviation of the received signal based on the transmission line response estimation step for estimating the transmission line response for each symbol and the estimated value of the estimated transmission line response by comparing each symbol while sliding. The frequency deviation calculation step for calculating the frequency deviation, the frequency correction step for correcting the frequency of the received signal for each symbol based on the calculated calculated value of the frequency deviation, and the synchronization included in the frequency-corrected received signal. From the correlation between the word and the predetermined synchronization word, the frequency deviation is synchronized with the synchronization word detection step for detecting the synchronization word included in the reception signal and the timing at which the synchronization word is detected. It includes a frequency deviation output step that takes in and outputs the calculated value of the frequency deviation calculated in the calculation step.

一実施の形態によれば、周波数偏差検出処理プログラムは、予め取得されている所定の同期ワードと、シングルキャリア伝送によって無線受信された受信信号に含まれる、前記所定の同期ワードに対応する同期ワードと、をスライドさせながらシンボル毎に比較することにより、シンボル毎に伝送路応答の推定を行う伝送路応答推定処理と、推定された前記伝送路応答の推定値に基づいて、前記受信信号の周波数偏差を算出する周波数偏差算出処理と、算出された前記周波数偏差の算出値に基づいて、シンボル毎に前記受信信号の周波数を補正する周波数補正処理と、周波数補正された前記受信信号に含まれる前記同期ワードと、前記所定の同期ワードと、の間の相関関係から、前記受信信号に含まれる前記同期ワードを検出する同期ワード検出処理と、前記同期ワードが検出されたタイミングに同期して、周波数偏差算出処理において算出された前記周波数偏差の算出値を取り込んで出力する周波数偏差出力処理と、をコンピュータに実行させる。 According to one embodiment, the frequency deviation detection processing program includes a predetermined synchronization word acquired in advance and a synchronization word corresponding to the predetermined synchronization word included in the received signal wirelessly received by the single carrier transmission. And, by comparing each symbol while sliding, the transmission line response estimation process that estimates the transmission line response for each symbol, and the frequency of the received signal based on the estimated estimated value of the transmission line response. The frequency deviation calculation process for calculating the deviation, the frequency correction process for correcting the frequency of the received signal for each symbol based on the calculated calculated value of the frequency deviation, and the frequency correction process included in the frequency-corrected received signal. The frequency is synchronized with the synchronization word detection process for detecting the synchronization word included in the received signal from the correlation between the synchronization word and the predetermined synchronization word, and the timing at which the synchronization word is detected. The computer is made to execute the frequency deviation output process of fetching and outputting the calculated value of the frequency deviation calculated in the deviation calculation process.

前記一実施の形態によれば、受信信号の周波数偏差を精度良く検出することが可能な周波数偏差検出回路、それを備えた受信機、周波数偏差検出方法、及び、周波数偏差検出プログラムを提供することができる。 According to the above embodiment, a frequency deviation detection circuit capable of accurately detecting the frequency deviation of a received signal, a receiver provided with the same, a frequency deviation detection method, and a frequency deviation detection program are provided. Can be done.

実施の形態１にかかる周波数偏差検出部の概要を示すブロック図である。It is a block diagram which shows the outline of the frequency deviation detection part which concerns on Embodiment 1. FIG. シンボルデータのフレーム構成の一例を示す図である。It is a figure which shows an example of the frame structure of a symbol data. 図１に示す周波数偏差検出部が受信機に適用された通信システムの構成例を示すブロック図である。FIG. 5 is a block diagram showing a configuration example of a communication system in which the frequency deviation detection unit shown in FIG. 1 is applied to a receiver. 図１に示す周波数偏差検出部のより具体的な構成例を示すブロック図である。It is a block diagram which shows a more specific configuration example of the frequency deviation detection part shown in FIG. 図４に示す周波数偏差検出部に設けられた周波数補正部の具体的な構成例を示すブロック図である。It is a block diagram which shows the specific structural example of the frequency correction part provided in the frequency deviation detection part shown in FIG. 周波数偏差検出部によるシンボルデータの処理フローの一部を示す図である。It is a figure which shows a part of the processing flow of the symbol data by a frequency deviation detection part.

以下、図面を参照しつつ、実施の形態について説明する。なお、図面は簡略的なものであるから、この図面の記載を根拠として実施の形態の技術的範囲を狭く解釈してはならない。また、同一の要素には、同一の符号を付し、重複する説明は省略する。 Hereinafter, embodiments will be described with reference to the drawings. Since the drawings are simple, the technical scope of the embodiments should not be narrowly interpreted based on the description of the drawings. Further, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

以下の実施の形態においては便宜上その必要があるときは、複数のセクションまたは実施の形態に分割して説明する。ただし、特に明示した場合を除き、それらはお互いに無関係なものではなく、一方は他方の一部または全部の変形例、応用例、詳細説明、補足説明等の関係にある。また、以下の実施の形態において、要素の数等（個数、数値、量、範囲等を含む）に言及する場合、特に明示した場合および原理的に明らかに特定の数に限定される場合等を除き、その特定の数に限定されるものではなく、特定の数以上でも以下でもよい。 In the following embodiments, when necessary for convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not unrelated to each other, and one has a relationship of a part or all of the other, a modified example, an application example, a detailed explanation, a supplementary explanation, and the like. In addition, in the following embodiments, when the number of elements (including the number, numerical value, quantity, range, etc.) is referred to, when it is specified in particular, or when it is clearly limited to a specific number in principle, etc. Except, the number is not limited to the specific number, and may be more than or less than the specific number.

さらに、以下の実施の形態において、その構成要素（動作ステップ等も含む）は、特に明示した場合および原理的に明らかに必須であると考えられる場合等を除き、必ずしも必須のものではない。同様に、以下の実施の形態において、構成要素等の形状、位置関係等に言及するときは、特に明示した場合および原理的に明らかにそうでないと考えられる場合等を除き、実質的にその形状等に近似または類似するもの等を含むものとする。このことは、上記数等（個数、数値、量、範囲等を含む）についても同様である。 Furthermore, in the following embodiments, the components (including operation steps and the like) are not necessarily essential unless otherwise specified or clearly considered to be essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc. of a component or the like, the shape is substantially the same unless otherwise specified or when it is considered that it is not apparent in principle. Etc., etc. shall be included. This also applies to the above numbers (including the number, numerical value, quantity, range, etc.).

＜実施の形態１＞
まず、図１を用いて、実施の形態１に係る受信機に搭載された周波数偏差検出部（周波数偏差検出回路）の概要について説明する。図１は、実施の形態１に係る周波数偏差検出部２３の概要を示すブロック図である。周波数偏差検出部２３は、無線通信システムの受信機に設けられ、送信機から送信された無線信号の周波数と、受信機によって受信された当該無線信号（受信信号）の周波数と、のずれ（周波数偏差）を検出する。受信機では、周波数偏差検出部２３によって検出された周波数偏差を用いて受信信号の周波数が補正された後、当該受信信号が復調される。 <Embodiment 1>
First, the outline of the frequency deviation detection unit (frequency deviation detection circuit) mounted on the receiver according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing an outline of the frequency deviation detection unit 23 according to the first embodiment. The frequency deviation detection unit 23 is provided in the receiver of the wireless communication system, and is provided with a deviation (frequency) between the frequency of the radio signal transmitted from the transmitter and the frequency of the radio signal (received signal) received by the receiver. Deviation) is detected. In the receiver, the frequency of the received signal is corrected using the frequency deviation detected by the frequency deviation detection unit 23, and then the received signal is demodulated.

なお、本実施の形態では、変調方式として、位相偏移変調方式や直交振幅変調方式が採用されている場合を例に説明する。また、本実施の形態では、伝送方式として、シングルキャリア伝送が採用されている。 In the present embodiment, a case where a phase shift keying method or a quadrature amplitude modulation method is adopted as the modulation method will be described as an example. Further, in the present embodiment, single carrier transmission is adopted as the transmission method.

さらに、本実施の形態では、受信信号のデータ構造として、図２に例示されるようなフレームが用いられる場合を例に説明する。具体的には、伝送される１つのフレームには、伝送されるデータに加えて、既知の同期ワード（ＳＷ）が含まれている。ここで、同期ワードは、同期対象となる送信機及び受信機において共通の固定化されたビットパターンを示している。なお、図２の例では、フレームの先頭以外の位置に同期ワードが配置されているが、フレームの先頭の位置に同期ワードが配置されていても良い。 Further, in the present embodiment, a case where a frame as illustrated in FIG. 2 is used as the data structure of the received signal will be described as an example. Specifically, one frame to be transmitted contains a known synchronization word (SW) in addition to the data to be transmitted. Here, the synchronization word indicates a fixed bit pattern common to the transmitter and the receiver to be synchronized. In the example of FIG. 2, the synchronization word is arranged at a position other than the beginning of the frame, but the synchronization word may be arranged at the beginning of the frame.

図１に示すように、周波数偏差検出部２３は、伝送路応答推定部２３１と、周波数偏差算出部２３２と、周波数補正部２３３と、同期ワード検出部２３５と、周波数保持部２３６と、を備える。 As shown in FIG. 1, the frequency deviation detection unit 23 includes a transmission line response estimation unit 231, a frequency deviation calculation unit 232, a frequency correction unit 233, a synchronization word detection unit 235, and a frequency holding unit 236. ..

伝送路応答推定部２３１は、予め取得されている既知の同期ワードＳＷと、シングルキャリア伝送によって無線受信された受信信号ＲＳのシンボルデータに含まれる、既知の同期ワードＳＷに対応する同期ワードと、をスライドさせながらシンボル毎に比較する。それにより、伝送路応答推定部２３１は、シンボル毎に伝送路応答の推定を行って伝送路応答の推定値を出力する。なお、詳しくは後述するが、伝送路応答推定部２３１に入力される受信信号ＲＳのシンボルデータとは、受信信号ＲＳをベースバンド信号に変換した後、波形成形等の処理を行うことによって生成された受信信号ＲＳのシンボル系列のことである。 The transmission line response estimation unit 231 includes a known synchronization word SW acquired in advance, a synchronization word corresponding to the known synchronization word SW included in the symbol data of the received signal RS wirelessly received by single carrier transmission, and a synchronization word. Compare each symbol while sliding. As a result, the transmission line response estimation unit 231 estimates the transmission line response for each symbol and outputs the estimated value of the transmission line response. As will be described in detail later, the symbol data of the received signal RS input to the transmission line response estimation unit 231 is generated by converting the received signal RS into a baseband signal and then performing processing such as waveform shaping. It is a symbol series of the received signal RS.

周波数偏差算出部２３２は、伝送路応答推定部２３１によって推定された伝送路応答の推定値に基づいて、受信信号ＲＳの周波数偏差を算出する。 The frequency deviation calculation unit 232 calculates the frequency deviation of the received signal RS based on the estimated value of the transmission line response estimated by the transmission line response estimation unit 231.

周波数補正部２３３は、周波数偏差算出部２３２によって算出された周波数偏差の算出値に基づいて、シンボル毎に、受信信号ＲＳのシンボルデータに対する周波数の補正を行う。 The frequency correction unit 233 corrects the frequency of the symbol data of the received signal RS for each symbol based on the calculated value of the frequency deviation calculated by the frequency deviation calculation unit 232.

同期ワード検出部２３５は、周波数補正されたシンボルデータを復調することにより得られたビットデータに含まれる同期ワードと、予め取得されている既知（所定）の同期ワードと、の間の相関関係から、当該ビットデータに含まれる同期ワードを検出する。 The synchronization word detection unit 235 is based on the correlation between the synchronization word included in the bit data obtained by demodulating the frequency-corrected symbol data and the known (predetermined) synchronization word acquired in advance. , Detects the synchronization word contained in the bit data.

周波数保持部２３６は、同期ワード検出部２３５によって同期ワードが検出されたタイミングに同期して、周波数偏差算出部２３２によって算出された周波数偏差の算出値を取り込んで出力する。 The frequency holding unit 236 captures and outputs the calculated value of the frequency deviation calculated by the frequency deviation calculation unit 232 in synchronization with the timing when the synchronization word is detected by the synchronization word detection unit 235.

このように、本実施の形態に係る周波数偏差検出部２３は、受信信号ＲＳのシンボルデータに対して、スライディングウィンドウ方式を用いてシンボル毎に伝送路応答の推定、周波数偏差の算出、及び、周波数の補正を行っている。それにより、本実施の形態に係る周波数偏差検出部２３は、低ＳＮ比環境下や周波数偏差が大きい場合でも、受信信号ＲＳの同期ワードと、既知の同期ワードと、の間の相関関係を高めることができるため、受信信号ＲＳの同期ワードを正確に検出することができる。そのため、本実施の形態に係る周波数偏差検出部２３は、受信信号ＲＳに含まれる同期ワードの検出タイミングにおける周波数偏差を正確に取得することができる。 As described above, the frequency deviation detection unit 23 according to the present embodiment uses the sliding window method for the symbol data of the received signal RS to estimate the transmission line response, calculate the frequency deviation, and frequency. Is being corrected. As a result, the frequency deviation detection unit 23 according to the present embodiment enhances the correlation between the synchronization word of the received signal RS and the known synchronization word even in a low SN ratio environment or when the frequency deviation is large. Therefore, the synchronization word of the received signal RS can be accurately detected. Therefore, the frequency deviation detection unit 23 according to the present embodiment can accurately acquire the frequency deviation at the detection timing of the synchronization word included in the received signal RS.

≪周波数偏差検出部２３が搭載された無線通信システム１００の例≫
図３は、周波数偏差検出部２３が受信機に搭載された無線通信システム１００の構成例を示すブロック図である。 << Example of wireless communication system 100 equipped with frequency deviation detection unit 23 >>
FIG. 3 is a block diagram showing a configuration example of the wireless communication system 100 in which the frequency deviation detection unit 23 is mounted on the receiver.

図３に示すように、無線通信システム１００は、送信機１と、受信機２と、を備える。送信機１は、デジタル変調部１１と、ベースバンド信号処理部１２と、ＲＦ信号送信部１３と、アンテナＡ１と、を少なくとも備える。受信機２は、ＲＦ信号受信部２１と、ベースバンド信号処理部２２と、周波数偏差検出部２３と、周波数補正部２４と、デジタル復調部２５と、アンテナＡ２と、を少なくとも備える。 As shown in FIG. 3, the wireless communication system 100 includes a transmitter 1 and a receiver 2. The transmitter 1 includes at least a digital modulation unit 11, a baseband signal processing unit 12, an RF signal transmission unit 13, and an antenna A1. The receiver 2 includes at least an RF signal receiving unit 21, a baseband signal processing unit 22, a frequency deviation detecting unit 23, a frequency correction unit 24, a digital demodulation unit 25, and an antenna A2.

送信機１において、デジタル変調部１１は、入力された送信データに対して変調処理を行い、シンボル系列（シンボルデータ）を出力する。ベースバンド信号処理部１２は、デジタル変調部１１から出力されたシンボル系列に対して、波形整形等の処理を行って、ベースバンド信号を出力する。ＲＦ信号送信部１３は、ベースバンド信号処理部１２から出力されたベースバンド信号に対して、周波数変換及び電力増幅等の処理を行って、ＲＦ（ＲａｄｉｏＦｒｅｑｕｅｎｃｙ）信号を出力する。このＲＦ信号は、アンテナＡ１を介して、無線送信される。 In the transmitter 1, the digital modulation unit 11 performs modulation processing on the input transmission data and outputs a symbol sequence (symbol data). The baseband signal processing unit 12 performs processing such as waveform shaping on the symbol sequence output from the digital modulation unit 11 and outputs the baseband signal. The RF signal transmission unit 13 performs processing such as frequency conversion and power amplification on the baseband signal output from the baseband signal processing unit 12, and outputs an RF (Radio Frequency) signal. This RF signal is wirelessly transmitted via the antenna A1.

受信機２は、送信機１から送信されたＲＦ信号（以下、受信信号ＲＳと称す）を、アンテナＡ２を介して受信する。ＲＦ信号受信部２１は、アンテナＡ２を介して受信した受信信号ＲＳに対して、周波数変換、電力増幅、及び、帯域制限等の処理を行って、ベースバンド信号を出力する。ベースバンド信号処理部２２は、ＲＦ信号受信部２１から出力されベースバンド信号に対して、波形整形等の処理を行って、シンボル系列を出力する。周波数偏差検出部２３は、ベースバンド信号処理部２２から出力された受信信号ＲＳのシンボル系列に含まれる同期ワードのシンボル系列と、既知の同期ワードのシンボル系列と、の間の相関関係から、受信信号ＲＳの周波数偏差を検出する。周波数補正部２４は、受信信号ＲＳのシンボル系列に対して、周波数偏差検出部２３により検出された周波数偏差を用いて補正処理を行って、補正後の受信信号ＲＳのシンボル系列を出力する。デジタル復調部２５は、周波数補正部２４から出力された補正後の受信信号ＲＳのシンボル系列に対して復調処理を行って、受信データとして出力する。 The receiver 2 receives the RF signal (hereinafter referred to as the received signal RS) transmitted from the transmitter 1 via the antenna A2. The RF signal receiving unit 21 performs processing such as frequency conversion, power amplification, and band limitation on the received signal RS received via the antenna A2, and outputs a baseband signal. The baseband signal processing unit 22 outputs a symbol sequence by performing processing such as waveform shaping on the baseband signal output from the RF signal receiving unit 21. The frequency deviation detection unit 23 receives from the correlation between the symbol sequence of the synchronization word included in the symbol sequence of the reception signal RS output from the baseband signal processing unit 22 and the symbol sequence of the known synchronization word. The frequency deviation of the signal RS is detected. The frequency correction unit 24 performs correction processing on the symbol series of the received signal RS using the frequency deviation detected by the frequency deviation detection unit 23, and outputs the symbol series of the received signal RS after correction. The digital demodulation unit 25 performs demodulation processing on the symbol series of the corrected received signal RS output from the frequency correction unit 24, and outputs it as received data.

≪周波数偏差検出部２３の詳細≫
図４は、周波数偏差検出部２３の詳細を周波数偏差検出部２３ａとして示すブロック図である。 << Details of frequency deviation detection unit 23 >>
FIG. 4 is a block diagram showing the details of the frequency deviation detection unit 23 as the frequency deviation detection unit 23a.

図４に示すように、周波数偏差検出部２３ａは、伝送路応答推定部２３１と、周波数偏差算出部２３２と、周波数補正部２３３と、デジタル復調部２３４と、同期ワード検出部２３５と、周波数保持部２３６と、を備える。また、周波数偏差検出部２３ａは、遅延部２３７と、遅延部２３８と、遅延部２３９と、スイッチＳＷ１，ＳＷ２と、をさらに備える。 As shown in FIG. 4, the frequency deviation detection unit 23a includes a transmission line response estimation unit 231, a frequency deviation calculation unit 232, a frequency correction unit 233, a digital demodulation unit 234, a synchronous word detection unit 235, and a frequency holding unit. A unit 236 and a unit are provided. Further, the frequency deviation detection unit 23a further includes a delay unit 237, a delay unit 238, a delay unit 239, and switches SW1 and SW2.

スイッチＳＷ１，ＳＷ２は、ベースバンド信号処理部２２から出力された受信信号ＲＳのシンボル系列を、当該シンボル系列から周波数偏差を検出する経路、及び、周波数偏差の検出に要する時間分遅延させて出力する経路、の何れかに周期的に切り替えて出力する。 The switches SW1 and SW2 output the symbol sequence of the received signal RS output from the baseband signal processing unit 22 with a delay of the path for detecting the frequency deviation from the symbol sequence and the time required for detecting the frequency deviation. It is output by periodically switching to one of the routes.

伝送路応答推定部２３１は、予め取得されている既知の同期ワードＳＷと、シングルキャリア伝送によって無線受信された受信信号ＲＳのシンボル系列に含まれる、既知の同期ワードＳＷに対応する同期ワードと、をスライドさせながらシンボル毎に比較する。それにより、伝送路応答推定部２３１は、シンボル毎に伝送路応答の推定を行って伝送路応答の推定値を出力する。 The transmission line response estimation unit 231 includes a known synchronization word SW acquired in advance, a synchronization word corresponding to the known synchronization word SW included in the symbol sequence of the received signal RS wirelessly received by single carrier transmission, and a synchronization word. Compare each symbol while sliding. As a result, the transmission line response estimation unit 231 estimates the transmission line response for each symbol and outputs the estimated value of the transmission line response.

遅延部２３７は、受信信号ＲＳのシンボルデータを、伝送路応答推定部２３１及び周波数偏差算出部２３２の処理に要する時間分遅延させて出力する。 The delay unit 237 outputs the symbol data of the received signal RS with a delay of the time required for the processing of the transmission line response estimation unit 231 and the frequency deviation calculation unit 232.

図５は、周波数偏差算出部２３２の具体的な構成例を示すブロック図である。周波数偏差算出部２３２は、数値制御発振器２３３１と、複素乗算器２３３２と、を有する。図５を参照すると、数値制御発振器２３３１は、周波数偏差算出部２３２によって算出された周波数偏差の算出値に応じた周波数の発振信号を出力する。複素乗算器２３３２は、数値制御発振器２３３１から出力された発振信号と、受信信号ＲＳのシンボルデータと、の間で複素乗算処理を行って、周波数補正後のシンボルデータを出力する。 FIG. 5 is a block diagram showing a specific configuration example of the frequency deviation calculation unit 232. The frequency deviation calculation unit 232 includes a numerically controlled oscillator 2331 and a complex multiplier 2332. Referring to FIG. 5, the numerically controlled oscillator 2331 outputs an oscillation signal having a frequency corresponding to the calculated value of the frequency deviation calculated by the frequency deviation calculation unit 232. The complex multiplier 2332 performs complex multiplication processing between the oscillation signal output from the numerically controlled oscillator 2331 and the symbol data of the received signal RS, and outputs the symbol data after frequency correction.

図６は、周波数偏差検出部２３に設けられた伝送路応答推定部２３１、周波数偏差算出部２３２、及び、周波数補正部２３３による処理フローを示す図である。図６に示すように、周波数偏差検出部２３では、受信信号ＲＳのシンボルデータに対して、スライディングウィンドウ方式を用いてシンボル毎に伝送路応答の推定、周波数偏差の算出、及び、周波数の補正が行われている。それにより、受信信号ＲＳのシンボルデータに含まれる同期ワードの最後のシンボルのタイミングにおいてのみ、正確な周波数の補正が可能となる。 FIG. 6 is a diagram showing a processing flow by the transmission line response estimation unit 231 provided in the frequency deviation detection unit 23, the frequency deviation calculation unit 232, and the frequency correction unit 233. As shown in FIG. 6, the frequency deviation detection unit 23 uses a sliding window method to estimate the transmission line response, calculate the frequency deviation, and correct the frequency for the symbol data of the received signal RS. It is done. As a result, accurate frequency correction is possible only at the timing of the last symbol of the synchronization word included in the symbol data of the received signal RS.

デジタル復調部２３４は、周波数補正部２３３から出力された周波数補正されたシンボルデータに対して復調処理を行って、ビットデータを出力する。 The digital demodulation unit 234 performs demodulation processing on the frequency-corrected symbol data output from the frequency correction unit 233, and outputs bit data.

同期ワード検出部２３５は、デジタル復調部２３４から出力されたビットデータに含まれる同期ワードと、予め取得されている既知の同期ワードと、の間の相関関係から、当該ビットデータに含まれる同期ワードを検出する。なお、同期ワード検出部２３５は、波形相関から、ビットデータに含まれる同期ワードを検出しても良い。 The synchronization word detection unit 235 has a synchronization word included in the bit data based on the correlation between the synchronization word included in the bit data output from the digital demodulation unit 234 and the known synchronization word acquired in advance. Is detected. The synchronization word detection unit 235 may detect the synchronization word included in the bit data from the waveform correlation.

遅延部２３８は、周波数偏差算出部２３２から出力された周波数偏差の算出値を、周波数補正部２３３、デジタル復調部２３４、及び、同期ワード検出部２３５の処理に要する時間分遅延させて出力する。 The delay unit 238 delays the calculated value of the frequency deviation output from the frequency deviation calculation unit 232 by the time required for the processing of the frequency correction unit 233, the digital demodulation unit 234, and the synchronization word detection unit 235, and outputs the calculated value.

周波数保持部２３６は、同期ワード検出部２３５により同期ワードが検出されたタイミング（より詳細には、同期ワードの最後のシンボルが検出されたタイミング）に同期して、周波数偏差算出部２３２により算出された周波数偏差の算出値を取り込んで出力する。 The frequency holding unit 236 is calculated by the frequency deviation calculation unit 232 in synchronization with the timing when the synchronization word is detected by the synchronization word detection unit 235 (more specifically, the timing when the last symbol of the synchronization word is detected). The calculated value of the frequency deviation is taken in and output.

遅延部２３９は、受信信号ＲＳのシンボルデータを、周波数補正部２３３、デジタル復調部２３４、同期ワード検出部２３５、及び、周波数保持部２３６の処理に要する時間分遅延させて出力する。 The delay unit 239 outputs the symbol data of the received signal RS with a delay of the time required for processing of the frequency correction unit 233, the digital demodulation unit 234, the synchronous word detection unit 235, and the frequency holding unit 236.

それにより、周波数偏差検出部２３ａは、受信信号ＲＳのシンボル系列及びそれに対応する周波数偏差を出力する。その後、周波数補正部２４は、周波数偏差検出部２３から出力された受信信号ＲＳのシンボル系列に対して、同じく周波数偏差検出部２３から出力された周波数偏差を用いて補正処理を行って、補正後の受信信号ＲＳのシンボル系列を出力する。 As a result, the frequency deviation detection unit 23a outputs the symbol sequence of the received signal RS and the corresponding frequency deviation. After that, the frequency correction unit 24 performs correction processing on the symbol series of the received signal RS output from the frequency deviation detection unit 23 using the frequency deviation also output from the frequency deviation detection unit 23, and after correction. Outputs the symbol sequence of the received signal RS of.

このように、本実施の形態に係る周波数偏差検出部２３ａは、受信信号ＲＳのシンボルデータに対して、スライディングウィンドウ方式を用いてシンボル毎に伝送路応答の推定、周波数偏差の算出、及び、周波数の補正を行っている。それにより、本実施の形態に係る周波数偏差検出部２３ａは、低ＳＮ比環境下や周波数偏差が大きい場合でも、受信信号ＲＳの同期ワードと既知の同期ワードとの間の相関関係を高めることができるため、受信信号ＲＳの同期ワードを正確に検出することができる。そのため、本実施の形態に係る周波数偏差検出部２３ａは、受信信号ＲＳに含まれる同期ワードの検出タイミングにおける周波数偏差を正確に取得することができる。 As described above, the frequency deviation detection unit 23a according to the present embodiment uses the sliding window method for the symbol data of the received signal RS to estimate the transmission line response, calculate the frequency deviation, and frequency. Is being corrected. As a result, the frequency deviation detection unit 23a according to the present embodiment can enhance the correlation between the synchronization word of the received signal RS and the known synchronization word even in a low SN ratio environment or when the frequency deviation is large. Therefore, the synchronization word of the received signal RS can be accurately detected. Therefore, the frequency deviation detection unit 23a according to the present embodiment can accurately acquire the frequency deviation at the detection timing of the synchronization word included in the received signal RS.

なお、周波数偏差検出部２３（２３ａ）は、シンボル毎に、仮の伝送路応答の推定、周波数偏差の算出、及び、周波数の補正を行ったうえで同期ワードの検出を行うことにより、受信信号ＲＳの同期ワードと、既知の同期ワードと、の間の相関関係を高めている。このような手法は、シンボル毎に直接同期ワードの検出を行う特許文献２や、特許文献３の手法とは異なる。 The frequency deviation detection unit 23 (23a) detects the synchronous word after estimating the temporary transmission line response, calculating the frequency deviation, and correcting the frequency for each symbol, thereby detecting the received signal. It enhances the correlation between the RS sync word and the known sync word. Such a method is different from the methods of Patent Document 2 and Patent Document 3 in which the synchronous word is directly detected for each symbol.

本実施の形態では、受信機２が、自動周波数制御（ＡＦＣ：ＡｕｔｏｍａｔｉｃＦｒｅｑｕｅｎｃｙＣｏｎｔｒｏｌ）の機能を有していない場合について説明したが、これに限られない。受信機２は、自動周波数制御の機能を有していても良い。その場合、例えば、受信機２に設けられたＲＦ信号受信部２１は、フィードバックされた周波数偏差算出部２３２による周波数偏差の算出値を観測しながら、当該周波数偏差の算出値が小さくなるように受信信号ＲＳの周波数を調整するように構成される。受信信号ＲＳの周波数の調整は、例えば、ＲＦ信号受信部２１に設けられた発振器から出力される発振信号の発振周波数を調整することによって行われる。 In the present embodiment, the case where the receiver 2 does not have the function of automatic frequency control (AFC: Automatic Frequency Control) has been described, but the present invention is not limited to this. The receiver 2 may have an automatic frequency control function. In that case, for example, the RF signal receiving unit 21 provided in the receiver 2 receives the calculated value of the frequency deviation so as to be small while observing the calculated value of the frequency deviation by the fed-back frequency deviation calculating unit 232. It is configured to adjust the frequency of the signal RS. The frequency of the received signal RS is adjusted, for example, by adjusting the oscillation frequency of the oscillation signal output from the oscillator provided in the RF signal receiving unit 21.

以上、図面を参照して、本開示の実施の形態について詳しく説明してきたが、具体的な構成は上述のものに限られることはなく、本開示の要旨を逸脱しない範囲内において様々な設計変更等が可能である。 Although the embodiments of the present disclosure have been described in detail with reference to the drawings, the specific configuration is not limited to the above, and various design changes are made without departing from the gist of the present disclosure. Etc. are possible.

上述の実施の形態では、本開示をハードウェアの構成として説明したが、本開示は、これに限定されるものではない。本開示は、周波数偏差検出部２３の全部又は一部の処理を、ＣＰＵ（ＣｅｎｔｒａｌＰｒｏｃｅｓｓｉｎｇＵｎｉｔ）にコンピュータプログラムを実行させることにより実現することも可能である。 In the above-described embodiment, the present disclosure has been described as a hardware configuration, but the present disclosure is not limited thereto. The present disclosure can also be realized by causing a CPU (Central Processing Unit) to execute a computer program for all or part of the processing of the frequency deviation detection unit 23.

また、上述したプログラムは、様々なタイプの非一時的なコンピュータ可読媒体（ｎｏｎ−ｔｒａｎｓｉｔｏｒｙｃｏｍｐｕｔｅｒｒｅａｄａｂｌｅｍｅｄｉｕｍ）を用いて格納され、コンピュータに供給することができる。非一時的なコンピュータ可読媒体は、様々なタイプの実体のある記録媒体（ｔａｎｇｉｂｌｅｓｔｏｒａｇｅｍｅｄｉｕｍ）を含む。非一時的なコンピュータ可読媒体は、例えば、磁気記録媒体、光磁気記録媒体、ＣＤ−ＲＯＭ（ＲｅａｄＯｎｌｙＭｅｍｏｒｙ）、ＣＤ−Ｒ、ＣＤ−Ｒ／Ｗ、半導体メモリを含む。磁気記録媒体は、例えば、フレキシブルディスク、磁気テープ、ハードディスクドライブなどである。光磁気記録媒体は、例えば光り磁気ディスクなどである。半導体メモリは、例えば、マスクＲＯＭ、ＰＲＯＭ（ＰｒｏｇｒａｍｍａｂｌｅＲＯＭ）、ＥＰＲＯＭ（ＥｒａｓａｂｌｅＰＲＯＭ）、フラッシュＲＯＭ、ＲＡＭ（ＲａｎｄｏｍＡｃｃｅｓｓＭｅｍｏｒｙ）などである。また、プログラムは、様々なタイプの一時的なコンピュータ可読媒体（ｔｒａｎｓｉｔｏｒｙｃｏｍｐｕｔｅｒｒｅａｄａｂｌｅｍｅｄｉｕｍ）によってコンピュータに供給されてもよい。一時的なコンピュータ可読媒体の例は、電気信号、光信号、及び電磁波を含む。一時的なコンピュータ可読媒体は、電線及び光ファイバ等の有線通信路、又は無線通信路を介して、プログラムをコンピュータに供給できる。 In addition, the above-mentioned programs can be stored and supplied to a computer using various types of non-transitory computer readable media (non-transitory computer readable media). Non-transient computer-readable media include various types of tangible storage media (tangible storage media). Non-temporary computer-readable media include, for example, magnetic recording media, opto-magnetic recording media, CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories. The magnetic recording medium is, for example, a flexible disk, a magnetic tape, a hard disk drive, or the like. The optical magnetic recording medium is, for example, an optical magnetic disk. The semiconductor memory is, for example, a mask ROM, a PROM (Programmable ROM), an EPROM (Erasable PROM), a flash ROM, a RAM (Random Access Memory), or the like. The program may also be supplied to the computer by various types of temporary computer readable media (transitory computer readable media). Examples of temporary computer-readable media include electrical, optical, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

以上、実施の形態を参照して本願発明を説明したが、本願発明は上記によって限定されるものではない。本願発明の構成や詳細には、発明のスコープ内で当業者が理解し得る様々な変更をすることができる。 Although the invention of the present application has been described above with reference to the embodiments, the invention of the present application is not limited to the above. Various changes that can be understood by those skilled in the art can be made within the scope of the invention in the configuration and details of the invention of the present application.

１００無線通信システム
１送信機
２受信機
１１デジタル変調部
１２ベースバンド信号処理部
１３ＲＦ信号送信部
２１ＲＦ信号受信部
２２ベースバンド信号処理部
２３周波数偏差検出部
２３ａ周波数偏差検出部
２４周波数補正部
２５デジタル復調部
２３１伝送路応答推定部
２３２周波数偏差算出部
２３３周波数補正部
２３４デジタル復調部
２３５同期ワード検出部
２３６周波数保持部
２３７遅延部
２３８遅延部
２３９遅延部
２３３１数値制御発振器
２３３２複素乗算器
Ａ１アンテナ
Ａ２アンテナ
ＳＷ１スイッチ
ＳＷ２スイッチ 100 Radio communication system 1 Transmitter 2 Receiver 11 Digital modulation unit 12 Baseband signal processing unit 13 RF signal transmission unit 21 RF signal receiver 22 Baseband signal processing unit 23 Frequency deviation detection unit 23a Frequency deviation detection unit 24 Frequency correction unit 25 Digital demodulation unit 231 Transmission path response estimation unit 232 Frequency deviation calculation unit 233 Frequency correction unit 234 Digital demodulation unit 235 Synchronous word detection unit 236 Frequency retention unit 237 Delay unit 238 Delay unit 239 Delay unit 2331 Numerical control oscillator 2332 Complex multiplier A1 Antenna A2 Antenna SW1 switch SW2 switch

Claims

By comparing the predetermined synchronization word acquired in advance and the synchronization word corresponding to the predetermined synchronization word included in the received signal wirelessly received by the single carrier transmission for each symbol while sliding the symbol. A transmission line response estimation unit that estimates the transmission line response for each
A frequency deviation calculation unit that calculates the frequency deviation of the received signal based on the estimated value of the transmission line response estimated by the transmission line response estimation unit.
A first frequency correction unit that corrects the frequency of the received signal for each symbol based on the calculated value of the frequency deviation calculated by the frequency deviation calculation unit.
A synchronization word that detects the synchronization word included in the reception signal from the correlation between the synchronization word included in the reception signal frequency-corrected by the first frequency correction unit and the predetermined synchronization word. With the detector
A frequency holding unit that captures and outputs the calculated value of the frequency deviation calculated by the frequency deviation calculation unit in synchronization with the timing at which the synchronization word is detected by the synchronization word detection unit.
A frequency deviation detection circuit equipped with.

The frequency holding unit captures and outputs the calculated value of the frequency deviation calculated by the frequency deviation calculating unit in synchronization with the timing when the last symbol of the synchronization word is detected by the synchronization word detecting unit. Is composed of,
The frequency deviation detection circuit according to claim 1.

The frequency deviation detection circuit according to claim 1 or 2.
A second frequency correction unit that corrects the frequency of the received signal based on the detection value of the frequency deviation detected by the frequency deviation detection circuit.
Equipped with a receiver.

An RF signal receiver that receives the received signal and
The frequency deviation detection circuit according to claim 1 or 2.
With
The RF signal receiving unit observes the calculated value of the frequency deviation calculated by the frequency deviation calculating unit provided in the frequency deviation detecting circuit, and reduces the calculated value of the frequency deviation so that the received signal becomes smaller. Is configured to adjust the frequency of
Receiving machine.

A second frequency correction unit that corrects the frequency of the received signal based on the detection value of the frequency deviation detected by the frequency deviation detection circuit is further provided.
The receiver according to claim 4.

By comparing the predetermined synchronization word acquired in advance and the synchronization word corresponding to the predetermined synchronization word included in the received signal wirelessly received by the single carrier transmission for each symbol while sliding the symbol. A transmission line response estimation step that estimates the transmission line response for each,
A frequency deviation calculation step for calculating the frequency deviation of the received signal based on the estimated value of the transmission line response, and a frequency deviation calculation step.
A frequency correction step that corrects the frequency of the received signal for each symbol based on the calculated value of the frequency deviation, and
A synchronization word detection step for detecting the synchronization word included in the reception signal from the correlation between the synchronization word included in the frequency-corrected reception signal and the predetermined synchronization word.
A frequency deviation output step that takes in and outputs the calculated value of the frequency deviation calculated in the frequency deviation calculation step in synchronization with the timing at which the synchronization word is detected.
A frequency deviation detection method.

By comparing the predetermined synchronization word acquired in advance and the synchronization word corresponding to the predetermined synchronization word included in the received signal wirelessly received by the single carrier transmission for each symbol while sliding the symbol. Transmission line response estimation processing that estimates the transmission line response for each,
A frequency deviation calculation process that calculates the frequency deviation of the received signal based on the estimated value of the transmission line response, and
Frequency correction processing that corrects the frequency of the received signal for each symbol based on the calculated value of the frequency deviation,
A synchronization word detection process for detecting the synchronization word included in the reception signal from the correlation between the synchronization word included in the frequency-corrected reception signal and the predetermined synchronization word.
A frequency deviation output process that takes in and outputs the calculated value of the frequency deviation calculated in the frequency deviation calculation process in synchronization with the timing at which the synchronization word is detected.
A frequency deviation detection processing program that causes a computer to execute.