WO2023032160A1 - 無線通信システム、無線通信方法、および無線通信用送信装置 - Google Patents
無線通信システム、無線通信方法、および無線通信用送信装置 Download PDFInfo
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- This disclosure relates to a wireless communication system, a wireless communication method, and a wireless communication transmitter, and more particularly to a wireless communication system, a wireless communication method, and a wireless communication transmitter using a single-carrier multilevel modulation scheme.
- Non-Patent Document 1 discloses a technology related to a radio communication system using a single-carrier multilevel modulation method.
- the higher the transmission power the higher the SNR (Signal to Noise Ratio).
- a transmission signal amplifier generally exhibits linear input/output characteristics in a region where the input power is small, but exhibits nonlinear characteristics in a region where the power is large. Therefore, in wireless communication, the higher the transmission power, the more likely the transmission signal is distorted.
- Non-Patent Document 1 discloses a technique for keeping the transmission power within the linear region of the amplifier in order to avoid the influence of such distortion. In this case, since distortion is not superimposed on the transmission signal, the signal can be correctly processed in the receiving apparatus, and erroneous transmission of data can be effectively prevented.
- Non-Patent Document 1 uniformly keeps the transmission power within the linear region of the amplifier, and can be evaluated as imposing an excessive limitation on the capability of the amplifier.
- the present disclosure has been made in view of the above problems, and provides a wireless communication system that achieves excellent communication quality by effectively utilizing the capabilities of the amplifier of the transmitting device within the range where data misidentification does not occur.
- the first purpose is to
- a second object of the present disclosure is to provide a wireless communication method that achieves excellent communication quality by effectively utilizing the capabilities of the amplifier of the transmitting device within the range where data misidentification does not occur.
- a third object of the present disclosure is to provide a wireless communication transmitter capable of realizing excellent communication quality by effectively utilizing the capabilities of the amplifier within a range in which data misidentification does not occur. do.
- a first aspect is a wireless communication system including a transmitting device and a receiving device that perform wireless communication using a single-carrier multilevel modulation scheme,
- the transmitting device a transmission signal amplifier with variable transmission power; a transmission power control unit that controls transmission power used by the transmission signal amplifier; an error rate characteristic estimator for estimating an error rate of a received signal in the receiving device; a receiving unit that receives SNR information in the receiving device,
- the error rate characteristic estimator a process of estimating, based on the transmission power, a constellation corresponding to the modulation scheme and reflecting specifications relating to input/output characteristics of the transmission signal amplifier; Based on the characteristics of the constellation and the SNR, the process of estimating the error rate is configured to execute,
- the transmission power control section is configured to perform transmission power control processing for controlling the transmission power such that the error rate satisfies a predetermined request.
- a second aspect is a wireless communication method using a transmitting device and a receiving device that perform wireless communication using a single-carrier multilevel modulation method
- the transmission device comprises a transmission signal amplifier with variable transmission power, estimating, based on the transmission power, by the transmission device, a constellation corresponding to the modulation scheme and reflecting specifications relating to input/output characteristics of the transmission signal amplifier; the transmitting device receiving SNR information at the receiving device; the transmitting device estimating an error rate of a received signal in the receiving device based on the characteristics of the constellation and the SNR; the transmitting device controlling the transmission power such that the error rate satisfies a predetermined requirement; should be included.
- a third aspect is a radio communication transmitting apparatus that performs radio communication using a single-carrier multilevel modulation method, a transmission signal amplifier with variable transmission power; a transmission power control unit that controls transmission power used by the transmission signal amplifier; an error rate characteristic estimator for estimating the error rate of a received signal in a receiving device of a communication partner; a receiving unit that receives SNR information in the receiving device, The error rate characteristic estimator, a process of estimating, based on the transmission power, a constellation corresponding to the modulation scheme and reflecting specifications relating to input/output characteristics of the transmission signal amplifier; Based on the characteristics of the constellation and the SNR, the process of estimating the error rate is configured to execute, It is preferable that the transmission power control section is configured to perform processing for controlling the transmission power such that the error rate satisfies a predetermined request.
- the first to third aspects it is possible to effectively utilize the capability of the amplifier of the transmitting device within a range in which misidentification of data does not occur. Therefore, according to this aspect, it is possible to realize wireless communication with excellent quality while suppressing the amount of equipment investment.
- FIG. 1 is a diagram for explaining the overall configuration of a radio communication system according to Embodiment 1 of the present disclosure
- FIG. FIG. 2 is a diagram for explaining the configuration of a transmission device to be compared with the transmission device according to Embodiment 1 of the present disclosure
- FIG. 4 is a diagram showing input/output characteristics of an amplifier built into the transmission device
- FIG. 4 is a diagram showing how distortion occurs in a constellation as transmission power increases.
- 2 is a block diagram for explaining the configuration of a transmission device according to Embodiment 1 of the present disclosure
- FIG. 6 shows arithmetic expressions used by the transmitting apparatus shown in FIG. 5 to calculate the symbol error rate SER and the bit error rate BER, respectively.
- FIG. 4 is a diagram for explaining the concept of the number ⁇ M of nearest points;
- FIG. FIG. 4 is a diagram for explaining the concept of the minimum Euclidean distance in a distorted constellation;
- FIG. 4 is a flowchart for explaining the flow of processing executed by a transmitting device to control transmission power in Embodiment 1 of the present disclosure;
- FIG. 1 is a block diagram for explaining the configuration of a receiving device according to Embodiment 1 of the present disclosure;
- FIG. FIG. 4 is a diagram for explaining a method for a receiving device to calculate a likelihood for a receiving point in Embodiment 1 of the present disclosure;
- FIG. 1 shows the overall configuration of a radio communication system according to Embodiment 1 of the present disclosure.
- the wireless communication system of this embodiment includes a transmitter 10 and a receiver 12 .
- the transmitting device 10 is configured by, for example, a mobile communication base station operated by a communication carrier, or a WiFi (registered trademark) access point.
- the receiving device 12 is configured by a terminal station such as a smart phone or a tablet terminal.
- FIG. 2 is a block diagram for explaining the configuration of the transmission device 14 to be compared with the transmission device 10 in this embodiment.
- the transmission device 14 of the comparative example includes an information bit generator 16 .
- the information bit generator 16 generates information bits to be transmitted to the receiver 12 .
- the information bit generator 16 may have an error correction coding function or an interleaving function.
- the information bits generated by the information bit generator 16 are provided to the data signal modulator 18 .
- the data signal modulator 18 modulates the provided information bits into a data signal.
- the modulation method for example, quadrature amplitude modulation (QAM) or APSK, which can be used for a single-carrier multilevel modulation method, can be considered.
- the data signal generated by the data signal modulating section 18 is provided to the digital-to-analog converting section 20 .
- the digital-to-analog converter 20 converts the digital-modulated data signal into an analog transmission signal.
- the transmission signal generated by the digital-to-analog converter 20 is provided to the transmission signal amplifier 22 .
- the transmission signal amplifier 22 amplifies the transmission signal and provides it to the antenna 24 . Then, the transmission signal is transmitted from the antenna 24 toward the receiving device 12 in the form of a radio signal.
- FIG. 3 shows the input/output characteristics of the transmission signal amplifier 22.
- the output power (vertical axis) of the transmission signal amplifier 22 is proportional to the input power in a region where the input power (horizontal axis) is smaller than PB . Then, in the region where the input power exceeds PB , the proportional relationship is lost.
- a region in which the two are in a proportional relationship will be referred to as a "linear region”
- a region in which the proportional relationship between the two will be lost will be referred to as a "nonlinear region”.
- 64 symbols arranged in a lattice are defined by changing and adjusting the amplitudes of two mutually independent carriers.
- a point on the constellation coordinates where each of these 64 symbols is defined is hereinafter referred to as a "signal point”.
- a point on the constellation coordinates of each data signal that is actually transmitted is called a "receiving point”.
- the reception points form a distortion-free constellation, as shown on the left side of FIG. 4 (transmission power P 1 ).
- transmission power P 1 transmission power
- transmission power P N transmission power
- the receiving device 12 calculates the likelihood of each reception point included in the transmission signal with respect to signal points existing in the vicinity, and based on the result, treats each reception point as one of 64 symbols. recognize.
- the likelihood calculation can be performed, for example, by the method described in the following document.
- the receiving device 12 performs the above-described likelihood calculation using signal points forming a distortion-free constellation, the receiving points generated in the linear domain can be correctly recognized. However, reception points generated in the nonlinear region cannot be recognized correctly because they are shifted from their original positions on the constellation. Therefore, if the transmission signal amplifier 22 uses a nonlinear region, data may be misidentified in the receiving device 12 .
- the transmission device 10 is caused to execute transmission power control according to the following procedure. 1. Based on the set transmission power, the distortion that occurs in the constellation is predicted. 2. Based on the prediction results, the symbol error rate (SER) or bit error rate (BER) occurring in the receiver 12 is predicted. 3. Adjust the transmit power so that the SER or BER meets the requirements.
- SER symbol error rate
- BER bit error rate
- the transmission power of the transmission device 10 is appropriately controlled so that SER or BER clears the desired value. Therefore, according to the present embodiment, it is possible to effectively utilize the capability of the transmission signal amplifier 22 and efficiently obtain good communication quality.
- FIG. 5 is a block diagram for explaining the configuration of the transmission device 10 according to this embodiment.
- the same elements as those of the transmitting device 14 of the comparative example are denoted by the same reference numerals, and description thereof will be omitted or simplified.
- the transmission device 10 in this embodiment includes a transmission section shown in the upper part of FIG.
- the information bit generation section 16 in the transmission device 14 of the comparative example is replaced with an information bit generation section 26 .
- the information bit generator 26 included in the present embodiment generates information bits related to the specifications of the transmitter 10 when communication between the transmitter 10 and the receiver 12 is started. Specifically, the modulation scheme used by the transmitter 10 and the input/output characteristics of the transmission signal amplifier 22 (see FIG. 3) are converted into information bits.
- the information bits generated in this way are transmitted from the transmitting device 10 to the receiving device 12 when communication between the transmitting device 10 and the receiving device 12 is started. Therefore, in the present embodiment, the modulation method used by the transmission device 10 and the input/output characteristics of the transmission signal amplifier 22 are shared between them at the time the communication between them is started.
- the transmission device 10 in this embodiment includes a transmission power control section 28 in front of the transmission signal amplifier 22 .
- the transmission power control section 28 controls transmission power used by the transmission signal amplifier 22 so as to obtain desired communication quality.
- a control command from the transmission power control unit 28 is provided to the transmission signal amplifier 22 and also to the transmission power information notification unit 30 .
- the transmission power information notification unit 30 provides the information bit generation unit 26 with the transmission power command value.
- the information bit generator 26 then generates bit information about the current transmission power and includes the information in the transmission data.
- a transmission signal including information on the transmission power is transmitted from the transmission device 10 of the present embodiment to the reception device 12 at the transmission power set by the transmission power control unit 28 .
- the transmission unit of the transmission device 10 further includes an error rate characteristic estimation unit 32.
- the error rate characteristic estimator 32 has a function of estimating the probability that the signal transmitted from the transmitter 10 is misidentified by the receiver 12 . Functions related to the error rate characteristic estimator 32 will be described later in detail with reference to FIGS. 6 to 8. FIG.
- the transmitting device 10 has a receiving section shown in the lower part of FIG.
- This receiver includes a received signal amplifier 34 that receives a received signal from the antenna 24 .
- the received signal amplifier 34 amplifies the received signal with an appropriate gain and provides it to the analog-to-digital converter 36 .
- the analog-to-digital converter 36 is a block for demodulating the received signal in analog form into a digital signal.
- the signal digitized by the analog-to-digital converter 36 is provided to the data signal equalizer 38 .
- the data signal equalization unit 38 is a block that obtains an estimated value of the transmission signal by back-calculating the amplitude and phase information of the channel response.
- a training signal is exchanged between the transmitting device 10 and the receiving device 12 prior to the data signal.
- the content of the training signal is shared in advance between the transmitting device 10 and the receiving device 12 . Therefore, the transmitting device 10 can detect the influence caused by the communication channel based on the actually received training signal.
- the data signal equalization unit 38 reflects the result of the training on the data signal received from the receiving device 12, thereby generating a data signal that cancels out the influence caused by the communication path.
- the data signal generated by the data signal equalization unit 38 is provided to the likelihood calculation unit 40 .
- the likelihood calculation unit 40 calculates the likelihood of the signal points on the constellation stored by itself for the reception points indicated by the data signal. Then, the signal point with the highest likelihood is recognized as the symbol intended by the current reception point.
- the signal symbolized by the likelihood calculation unit 40 is provided to the information bit detection unit 42 .
- the information bit detector 42 detects received bits from the symbolized signal. Also, the information bit detector 42 may have an error correction decoding function and an interleave function in accordance with the information bit generator 26, if necessary.
- the transmission device 10 of this embodiment includes the error rate characteristic estimator 32 .
- symbol error rate SER or bit error rate BER is sometimes used as an index of communication quality.
- the error rate characteristic estimating unit 32 calculates SER or BER in accordance with the content required as an index for evaluation using a method described below, and provides the result to the transmission power control unit 28 . Then, the transmission power control unit 28 sets the transmission power of the transmission device 10 so that the SER or BER falls within the required threshold.
- FIG. 6 shows an arithmetic expression (1) for the symbol error rate SER and an arithmetic expression (2) for the bit error rate BER.
- M is the number of signal points forming the constellation
- ⁇ s is the SNR per symbol and ⁇ b is the SNR per bit.
- FIG. 7 shows a 16QAM constellation.
- a constellation having M 16 signal points in total, four points in each quadrant, is constructed.
- the number of nearest points " ⁇ M " is four, as indicated by a triangle around it.
- FIG. 7 also shows " ⁇ M ".
- ⁇ M is a coefficient proportional to the minimum Euclidean distance in the constellation. That is, the equations (1) and (2) shown in FIG. 6 indicate that the error rate (SER, BER) is determined when the constellation ( ⁇ M , ⁇ M , m) and SNR ( ⁇ s, ⁇ b) are determined. represent.
- FIG. 8 is a diagram for explaining the concept of the minimum Euclidean distance in a distorted constellation.
- the transmit signal amplifier 22 uses the non-linear region, the signal point distance is compressed at the fringes of the constellation, as shown in FIG.
- the Euclidean distance between signal points 44 and 46 shown in FIG. 8 is sufficiently shorter than the Euclidean distance between signal points existing near the center of the constellation. Therefore, when a distorted constellation is used, it is necessary to extract the minimum Euclidean distance from the constellation and calculate SER or BER using ⁇ M or the like corresponding to the extracted value.
- the transmission device 10 can estimate the constellation formed by the actually transmitted signal regardless of whether the transmission power is in the linear region or the nonlinear region. can. If the actually formed constellation is known, ⁇ M and ⁇ M realized therein can be known. Furthermore, the transmitting device 10 can acquire SNR information from the receiving device 12 . Transmitter 10 can then estimate SER and BER expected to occur in receiver 12 by applying the information to equation (1) or (2).
- FIG. 9 is a flow chart for explaining the flow of processing executed by the transmitter 10 to calculate the error rate (SER, BER) according to the above principle and control the transmission power according to the result. Note that the routine shown in FIG. 9 is repeatedly started at predetermined time intervals after communication is established between the transmitting device 10 and the receiving device 12 .
- step 100 the initial value of the transmission power used by the transmission signal amplifier 22 is set.
- the transmitting device 10 emits a transmission signal with the set transmission power.
- the receiving device 12 Upon receiving the signal from the transmitting device 10, the receiving device 12 calculates SNR ( ⁇ s, ⁇ b) based on the strength of the signal. Then, it returns the calculated SNR to the transmitting device 10 . The transmitting device 10 acquires the returned SNR in this way (step 102).
- Transmitter 10 calculates the SER and BER that would be achieved under the current transmit power (step 104). Specifically, a constellation corresponding to the current transmission power is read, and ⁇ M and ⁇ M corresponding to that constellation are determined. Then, based on the number of bits m unique to the modulation scheme, the SNR ( ⁇ s, ⁇ b) obtained from the receiving device 12, and the above ⁇ M and ⁇ M , SER and BER are calculated by equation (1) or (2). calculate.
- the current routine is terminated while the transmission power is maintained as power for communication.
- step 106 determines whether or not the search for all possible transmission powers has been completed. For example, if the transmission power can be switched in N steps, it is determined whether the above steps 102 to 106 have been performed for all of the N steps.
- step 110 the transmission power is changed according to a predetermined rule (step 110). After that, the processing after step 102 is repeated.
- the SNR in the receiving device 12 changes and the magnitude of distortion superimposed on the constellation changes.
- the routine shown in FIG. 9 it is possible to find the transmission power that allows the error rate (SER, BER) to clear the requirements.
- the error rate SER, BER
- the use of transmission power belonging to the nonlinear region can be permitted. Therefore, according to this embodiment, by effectively using the capability of the transmission signal amplifier 22 within a range in which misidentification of data does not occur, excellent communication quality can be efficiently realized.
- FIG. 10 is a block diagram for explaining the configuration of the receiving device 12 in this embodiment.
- Receiver 12 includes elements that, in many respects, function substantially the same as those included in transmitter 10 .
- the transmission section of the reception device 12 has a configuration that functions substantially in the same manner as the transmission section of the transmission device 10 .
- the receiving section of receiving apparatus 12 has a configuration for functioning in substantially the same manner as the receiving section of transmitting apparatus 10 except for SNR estimating section 68 and likelihood calculating section 70 .
- description of substantially common functions will be omitted, and the features of the receiving device 12 will be described in detail.
- the SNR estimation unit 68 calculates the SNR of the signal received from the transmission device 10.
- the SNR estimated by the SNR estimator 68 is provided to the information bit generator 48 and then transmitted from the transmitter of the receiver 12 to the transmitter 10 .
- the likelihood calculator 70 calculates the likelihood of the reception point based on the transmission power used by the transmitter 10 .
- FIG. 11 is a diagram for explaining the function of the likelihood calculation unit 70.
- the left side of FIG. 11 shows an outline of likelihood calculation when the transmission device 10 uses the transmission power P1 .
- the constellation of the received signal has no distortion in which the signal points 74 are correctly arranged in a grid pattern.
- the likelihood calculator 70 refers to the constellation and calculates the likelihood of some of the signal points 74 located near the receiving point 76 using a normal distribution for the Euclidean distance between them. Then, the signal point 74 with the highest likelihood is adopted as the symbol corresponding to the receiving point 76 .
- the right side of FIG. 11 shows an outline of likelihood calculation when the transmission device 10 uses the transmission power P N .
- the constellation of the received signal includes a shift caused by the nonlinearity of the transmitted signal amplifier 22 at each of the signal points 74 .
- the likelihood calculator 70 refers to the constellation with the shift and calculates the likelihood of the receiving point 76 by the same technique as described above. Then, based on the result, the symbol that the reception point 76 means is specified.
- the modulation method and the input/output characteristics of the transmission signal amplifier 22 are shared between the transmission device 10 and the reception device 12 .
- the transmitting device 10 sequentially provides the receiving device 12 with information on the transmission power used for communication. Then, as described with reference to FIG. 11, the receiving device 12 performs likelihood calculation based on the constellation reproduced according to the transmission power.
- this embodiment allows the transmission device 10 to use the nonlinear region of the transmission signal amplifier 22 . Further, the transmission device 10 controls transmission power so that the error rate (SER, BER) satisfies the requirements. Therefore, according to the present embodiment, it is possible to reliably avoid occurrence of an excessive error rate due to the use of excessive transmission power.
- SER error rate
- the receiver 12 performs likelihood calculation on the assumption of the distortion. Therefore, according to the present embodiment, when the transmitting device 10 uses transmission power determined to be usable based on the error rate (SER, BER), the receiving device 12 is responsible for misidentifying data. The occurrence of such a situation can be effectively avoided.
- SER error rate
- the search for the transmission power is terminated when the transmission power satisfying the desired error rate (SER, BER) is found.
- SER desired error rate
- the present disclosure is not so limited.
- the search may be continued even after the condition that the error rate satisfies the requirement is found, and the transmission power that minimizes the error rate may be found.
- the transmission device 10 provides the specifications of the transmission signal amplifier 22 to the reception device 12 at the start of wireless communication.
- the present disclosure is not so limited.
- the transmitting device 10 may store the receiving device 12 that has provided the specifications, and the receiving device 12 that has received the specifications may store the information. Then, for the second and subsequent communications between the two, the transmission and reception of the above specification may be omitted.
- the transmission device 10 provides the reception device 12 with the specifications of the transmission signal amplifier 22 as well as information on the modulation scheme used for wireless communication.
- the present disclosure is not so limited. For example, if the modulation scheme used for communication between the transmitting device 10 and the receiving device 12 is determined in advance, providing the information on the modulation scheme can be omitted.
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Abstract
Description
前記送信装置は、
送信電力が可変の送信信号増幅器と、
前記送信信号増幅器が用いる送信電力を制御する送信電力制御部と、
前記受信装置における受信信号の誤り率を推定する誤り率特性推定部と、
前記受信装置におけるSNRの情報を受信する受信部と、を備え、
前記誤り率特性推定部は、
前記変調方式に対応し、かつ、前記送信信号増幅器の入出力特性に関する仕様が反映されたコンスタレーションを、前記送信電力に基づいて推定する処理と、
前記コンスタレーションの特性と、前記SNRとに基づいて、前記誤り率を推定する処理と、を実行するように構成されており、
前記送信電力制御部は、前記誤り率が、既定の要求を満たすように前記送信電力を制御する送信電力制御処理を実行するように構成されていることが望ましい。
前記送信装置は、送信電力が可変の送信信号増幅器を備え、
前記送信装置が、前記変調方式に対応し、かつ、前記送信信号増幅器の入出力特性に関する仕様が反映されたコンスタレーションを、前記送信電力に基づいて推定するステップと、
前記送信装置が、前記受信装置におけるSNRの情報を受信するステップと、
前記送信装置が、前記コンスタレーションの特性と、前記SNRとに基づいて、前記受信装置における受信信号の誤り率を推定するステップと、
前記送信装置が、前記誤り率が既定の要求を満たすように前記送信電力を制御するステップと、
を含むことが望ましい。
送信電力が可変の送信信号増幅器と、
前記送信信号増幅器が用いる送信電力を制御する送信電力制御部と、
通信相手の受信装置における受信信号の誤り率を推定する誤り率特性推定部と、
前記受信装置におけるSNRの情報を受信する受信部と、を備え、
前記誤り率特性推定部は、
前記変調方式に対応し、かつ、前記送信信号増幅器の入出力特性に関する仕様が反映されたコンスタレーションを、前記送信電力に基づいて推定する処理と、
前記コンスタレーションの特性と、前記SNRとに基づいて、前記誤り率を推定する処理と、を実行するように構成されており、
前記送信電力制御部は、前記誤り率が、既定の要求を満たすように前記送信電力を制御する処理を実行するように構成されていることが望ましい。
[実施の形態1の全体構成]
図1は、本開示の実施の形態1の無線通信システムの全体構成を示す。図1に示すように、本実施形態の無線通信システムは、送信装置10と受信装置12を備えている。送信装置10は、例えば、通信事業者が運営する移動体通信の基地局、或いはWiFi(登録商標)のアクセスポイント等で構成される。また、受信装置12は、スマートフォンやタブレット端末等の端末局で構成される。
図2は、本実施形態における送信装置10と対比される比較対象の送信装置14の構成を説明するためのブロック図である。比較例の送信装置14は、情報ビット生成部16を備えている。情報ビット生成部16は、受信装置12に伝送したい情報ビットを生成する。情報ビット生成部16は、誤り訂正符号化機能、或いはインターリーブ機能を備えていてもよい。
1.設定した送信電力に基づいて、コンスタレーションに生ずる歪みを予測する。
2.その予測の結果に基づいて、受信装置12で生ずるシンボル誤り率SER(Symbol Error Rate)或いはビット誤り率BER(Bit Error Rate)を予測する。
3.SER或いはBERが要求を満たすように、送信電力を調整する。
上記の通り、本実施形態の送信装置10は誤り率特性推定部32を備えている。無線通信の分野では、通信品質の指標としてシンボル誤り率SER、或いはビット誤り率BERが用いられることがある。誤り率特性推定部32は、以下に説明する手法により、評価の指標として求められる内容に応じてSERまたはBERを算出し、その結果を送信電力制御部28に提供する。そして、送信電力制御部28は、SERまたはBERが要求閾値に収まるように送信装置10の送信電力を設定する。
図9は、送信装置10が、上記の原理に従って誤り率(SER、BER)を計算すると共に、その結果に従って送信電力を制御するための実行する処理の流れを説明するためのフローチャートである。尚、図9に示すルーチンは、送信装置10と、受信装置12との間で通信が確立された後、既定の時間毎に繰り返し起動されるものとする。
図10は、本実施形態における受信装置12の構成を説明するためのブロック図である。受信装置12は、多くの部分において、実質的に送信装置10が備える要素と同様に機能する要素を備えている。
ところで、上述した実施の形態1では、誤り率(SER、BER)が所望の要求をクリアする送信電力が見つかった時点で、送信電力の探索を終了することとしている。しかしながら、本開示はこれに限定されるものではない。例えば、誤り率が要求をクリアする条件が見つかった後も探索を続けて、誤り率が最も小さくなる送信電力を見出すこととしてもよい。
12 受信装置
22 送信信号増幅器
26 情報ビット生成部
28 送信電力制御部
30 送信電力情報通知部
32 誤り率特性推定部
68 SNR推定部
70 尤度算出部
Claims (8)
- シングルキャリア多値変調方式を用いて無線通信を行う送信装置と受信装置を含む無線通信システムであって、
前記送信装置は、
送信電力が可変の送信信号増幅器と、
前記送信信号増幅器が用いる送信電力を制御する送信電力制御部と、
前記受信装置における受信信号の誤り率を推定する誤り率特性推定部と、
前記受信装置におけるSNRの情報を受信する受信部と、を備え、
前記誤り率特性推定部は、
前記変調方式に対応し、かつ、前記送信信号増幅器の入出力特性に関する仕様が反映されたコンスタレーションを、前記送信電力に基づいて推定する処理と、
前記コンスタレーションの特性と、前記SNRとに基づいて、前記誤り率を推定する処理と、を実行するように構成されており、
前記送信電力制御部は、前記誤り率が、既定の要求を満たすように前記送信電力を制御する送信電力制御処理を実行するように構成されている無線通信システム。 - 前記送信装置は、
前記受信装置に、前記仕様を提供する処理と、
前記受信装置に、前記送信信号増幅器が用いる送信電力の情報を提供する処理と、を実行するように構成されており、
前記受信装置は、
受信したデータ信号に基づいて前記SNRを推定するSNR推定部と、
前記データ信号について尤度を計算する尤度算出部と、
前記尤度の計算結果に基づいて、前記データ信号から情報ビットを検出する情報ビット検出部と、を備え、
前記尤度算出部は、
前記送信装置から提供を受けた前記仕様と前記送信電力に基づいて、当該送信電力に対応するコンスタレーションを推定する処理と、
前記データ信号について、当該コンスタレーションに含まれる信号点に対する尤度を計算する処理と、を実行するように構成されている請求項1に記載の無線通信システム。 - 前記誤り率特性推定部は、送信電力が設定される毎に、当該送信電力に対応する前記誤り率を推定するように構成されており、
前記送信電力制御処理は、
送信電力に初期値を設定する処理と、
前記送信信号増幅器が用いる送信電力に対応する前記誤り率が前記要求を満たすか否かを判別する処理と、
前記誤り率が前記要求を満たすと判別された場合に、前記送信電力を通信に用いるものとして維持する処理と、
前記誤り率が前記要求を満たさないと判別された場合に、前記送信電力を新たな値に設定する処理と、を含む請求項1または2に記載の無線通信システム。 - 前記誤り率特性推定部は、送信電力が設定される毎に、当該送信電力に対応する前記誤り率を推定するように構成されており、
前記送信電力制御処理は、
前記送信信号増幅器が取り得る全ての範囲において、前記送信電力を順次新たな値に設定する処理と、
前記全ての範囲について探索が終了した時点で、最善の誤り率を示す送信電力を、通信に用いるものとして選択する処理と、を含む請求項1または2に記載の無線通信システム。 - シングルキャリア多値変調方式を用いて無線通信を行う送信装置と受信装置とを用いる無線通信方法であって、
前記送信装置は、送信電力が可変の送信信号増幅器を備え、
前記送信装置が、前記変調方式に対応し、かつ、前記送信信号増幅器の入出力特性に関する仕様が反映されたコンスタレーションを、前記送信電力に基づいて推定するステップと、
前記送信装置が、前記受信装置におけるSNRの情報を受信するステップと、
前記送信装置が、前記コンスタレーションの特性と、前記SNRとに基づいて、前記受信装置における受信信号の誤り率を推定するステップと、
前記送信装置が、前記誤り率が既定の要求を満たすように前記送信電力を制御するステップと、
を含む無線通信方法。 - 前記送信装置が、前記受信装置に、前記仕様を提供するステップと、
前記送信装置が、前記受信装置に、前記送信信号増幅器が用いる送信電力の情報を提供するステップと、
前記受信装置が、前記仕様と前記送信電力に基づいて、当該送信電力に対応するコンスタレーションを推定するステップと、
前記受信装置が、受信したデータ信号について、当該コンスタレーションに含まれる信号点に対する尤度を計算するステップと、
前記受信装置が、前記尤度の計算結果に基づいて、前記データ信号から情報ビットを検出するステップと、
を含む請求項5に記載の無線通信方法。 - 前記送信装置が、送信電力が設定される毎に、当該送信電力に対応する前記誤り率を推定するステップと、
前記送信装置が、送信電力に初期値を設定するステップと、
前記送信装置が、前記送信信号増幅器が用いる送信電力に対応する前記誤り率が前記要求を満たすか否かを判別するステップと、
前記送信装置が、前記誤り率が前記要求を満たすと判別された場合に、前記送信電力を通信に用いるものとして維持するステップと、
前記送信装置が、前記誤り率が前記要求を満たさないと判別された場合に、前記送信電力を新たな値に設定するステップと、
を含む請求項5または6に記載の無線通信方法。 - シングルキャリア多値変調方式を用いて無線通信を行う無線通信用送信装置であって、
送信電力が可変の送信信号増幅器と、
前記送信信号増幅器が用いる送信電力を制御する送信電力制御部と、
通信相手の受信装置における受信信号の誤り率を推定する誤り率特性推定部と、
前記受信装置におけるSNRの情報を受信する受信部と、を備え、
前記誤り率特性推定部は、
前記変調方式に対応し、かつ、前記送信信号増幅器の入出力特性に関する仕様が反映されたコンスタレーションを、前記送信電力に基づいて推定する処理と、
前記コンスタレーションの特性と、前記SNRとに基づいて、前記誤り率を推定する処理と、を実行するように構成されており、
前記送信電力制御部は、前記誤り率が、既定の要求を満たすように前記送信電力を制御する処理を実行するように構成されている無線通信用送信装置。
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