JPH0983600A - Multilevel adaptative modulation radio device - Google Patents

Multilevel adaptative modulation radio device

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Publication number
JPH0983600A
JPH0983600A JP7260928A JP26092895A JPH0983600A JP H0983600 A JPH0983600 A JP H0983600A JP 7260928 A JP7260928 A JP 7260928A JP 26092895 A JP26092895 A JP 26092895A JP H0983600 A JPH0983600 A JP H0983600A
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Japan
Prior art keywords
modulation
circuit
level
transmission
transmission power
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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JP7260928A
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Japanese (ja)
Inventor
Katsuhiro Asano
Masashi Naito
Kenzo Urabe
昌志 内藤
健三 占部
勝洋 浅野
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Kokusai Electric Co Ltd
国際電気株式会社
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Application filed by Kokusai Electric Co Ltd, 国際電気株式会社 filed Critical Kokusai Electric Co Ltd
Priority to JP7260928A priority Critical patent/JPH0983600A/en
Publication of JPH0983600A publication Critical patent/JPH0983600A/en
Application status is Pending legal-status Critical

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/0001Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H04L1/0003Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes

Abstract

PROBLEM TO BE SOLVED: To improve the power efficiency of a transmission power amplifier circuit by reducing the back-off of the transmission power amplifier circuit when executing transmission under a relatively insufficient transmission line conditions while considering reliability and suppressing the number of bits per symbol. SOLUTION: A control circuit 14 keeps an error rate in the transmission line conditions at this time to a prescribed value and blow based on an estimation signal by a transmission line estimation circuit 3, selects a modulation system capable of obtaining the maximum information speed and transmits a control signal instructing mapping by this modulation system to a symbol mapping circuit 5. The control signal is transmitted to the transmission power amplifier circuit 17 and instructs the extent of back-off in an amplification operation. When the transmission line conditions is insufficientry, the modulation system is made the system in which multilevel value is small and the zero point of constellation does not cross, then the back-off of the transmission power amplifier circuit 17 is reduced. When the transmission line conditions are satisfactory, the modulation multilevel value is enlarged, and the transmission power amplifier circuit 17 executes an amplification operation in a state large in back-off.

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【発明の属する技術分野】本願発明は、TDD(Time D The present invention relates to the, TDD (Time D
ivision Duplex)通信方式のディジタル無線通信において、受信した信号から伝搬路状況(すなわち回線の品質)を推定し、この推定結果に応じて変調方式を自動的に切替えて変調動作を行ない、その上で送信等を行なう多値適応変調無線装置に関する。 In a digital radio communication iVision Duplex) communication system estimates the channel state (i.e., quality of the line) from the received signal, performs modulation operation automatically switches the modulation scheme according to the estimated result, on the about multilevel adaptive modulation wireless device to transmit the like.

【0002】 [0002]

【従来の技術】受信信号と送信信号とを同一の周波数で交互に送受信するTDD通信で用いる従来の多値適応変調無線装置としては、例えば、スクウェア型多値QAM Conventional multi-level adaptive modulation wireless device using the Related Art a transmission signal and a reception signal in the TDD communication for transmitting and receiving alternately at the same frequency, for example, square type multilevel QAM
の変調多値数およびシンボルレート(すなわち伝送レート)を伝搬路状況に応じて、自動的に切替える図4に示すようなものが公表されている(電子情報通信学会技術報告RCS94−64)。 Modulation level and symbol rate (i.e. transmission rate) according to the propagation path situation, automatically switching the kind shown in FIG. 4 has been published in (IEICE Technical Report RCS94-64). なお、TDD通信で用いられるこの種の多値適応変調無線装置は、以下の点に着目するものである。 Incidentally, this kind of multi-level adaptive modulation radio apparatus used in a TDD communication is intended to note the following points. すなわち連続する受信信号と送信信号とは、可逆性原理により、同じフェージング変動をしている伝搬路を通るとみなせるので、受信信号から測定した伝搬路のC/No(搬送波電力対雑音電力密度比)や遅延スプレッドを用いて、次の送信タイミングにおける伝搬路状況を推定できる点に着目するものである。 That The transmit and receive signals for successive, by reversibility principle, since regarded as through the channel that the same fading fluctuation, C / No (carrier power to noise power density ratio of the channel measured from the received signal ) and using a delay spread, is intended to note that it can estimate the channel state at the next transmission timing.

【0003】図4において、受信部2は、送受信アンテナ1で受信した受信信号に対し直交検波および復号等を行ない受信データを得て、この受信データを送出する回路部である。 [0003] In FIG 4, the receiving unit 2 obtains the reception data subjected to quadrature detection and decoding, etc. on the received signal received by the receiving antenna 1, a circuit portion for transmitting the received data. 伝搬路推定回路3は、受信部2から受信ベースバンド信号やRSSI(Received Signal Strength Channel estimation circuit 3, the receiving unit 2 received baseband signal and RSSI (Received Signal Strength
Indicator)等の受信レベル情報を取込み、これらを用いて今回の受信タイミングにおけるC/Noや遅延スプレッド等を検出し、検出結果に基づいて次の送信タイミングにおける伝搬路状況を推定し、推定結果である推定信号を送出する回路である。 The reception level information Indicator) such as uptake, these detect the C / No and delay spread, etc. at the current reception timing used to estimate the channel state at the next transmission timing based on the detection result, the estimated result a circuit for transmitting a certain estimation signal.

【0004】変調レベル制御回路4は、上記伝搬路推定回路3からの推定信号を入力し、この信号に基づいて、 [0004] modulation level control circuit 4 receives the estimation signal from the channel estimation circuit 3, on the basis of this signal,
上記伝搬路状況下で(すなわち推定した伝搬路状況下で)、誤り率を所定値以下に保ちつつ、最大の情報速度を得られる変調方式おびシンボルレートの組合わせを選択して、この組合わせでの変調を指示する制御信号をシンボルマッピング回路5に送出する回路部である。 Under the channel state (i.e. under propagation condition estimated), and select the combination of the modulation scheme Obi symbol rate while maintaining the error rate below a predetermined value, obtain a maximum information rate, this combination a circuit portion for transmitting a control signal for instructing the symbol mapping circuit 5 modulates in.

【0005】シンボルマッピング回路5は、与えられた送信データを上記変調レベル制御回路4よりの制御信号で指示された変調方式のシンボルにマッピングし、更に上記制御信号で指示されたシンボルレート(伝送レート)での複素ベースバンド信号を得て、この信号を直交変調回路6に送出する回路部である。 [0005] The symbol mapping circuit 5, given the transmit data mapped to the symbol of the modulation scheme indicated in the control signal from the modulation level control circuit 4, further indicated symbol rate by the control signal (transmission rate ) to obtain a complex baseband signal in a circuit portion for transmitting the signal to the quadrature modulation circuit 6. 直交変調回路6 Quadrature modulation circuit 6
は、搬送波を上記シンボルマッピング回路5からの複素ベースバンド信号により変調し、変調波を送信電力増幅回路7に送出する回路部である。 A carrier wave modulated by a complex baseband signal from the symbol mapping circuit 5, a circuit portion for transmitting the modulated wave to the transmission power amplifying circuit 7. 送信電力増幅回路7 Transmission power amplifying circuit 7
は、線形すなわちA級の電力増幅器となっており、上記直交変調回路6からの変調波を入力して、この変調波の電力を増幅して出力する回路部である。 Is linear i.e. has a class A power amplifier, and receives the modulation wave from the quadrature modulation circuit 6 is a circuit unit for amplifying and outputting the power of the modulated wave. この送信電力増幅回路7で電力増幅された上記変調波は、送受信アンテナ1より空間に輻射されることになる。 The modulated wave power-amplified by the transmission power amplifier circuit 7 will be radiated into space from the transmission and reception antenna 1.

【0006】ところで、上記変調レベル制御回路4がシンボルマッピング回路5に指示する各変調方式においては、図5に示すように、変調多値数が大きくなる程、1 [0006] In each modulation scheme the modulation level control circuit 4 instructs the symbol mapping circuit 5, as shown in FIG. 5, as the modulation level increases, 1
シンボル当りの情報量は増えるが、信頼度(伝搬路状況が比較的劣悪でも誤り率を一定値以下に保てる度合)は低下し、逆に変調多値数が小さくなる程、1シンボル当りの情報量は減少するが、信頼度は向上する。 Amount of information per symbol is increased, the reliability (degree of maintain the channel condition is relatively poor even error rate below a certain value) is reduced, as the inverse to the modulation level decreases, per symbol information the amount is decreased, the reliability is improved. すなわち上記変調レベル制御回路4は、適応変調を実行するため、伝搬路状況が比較的劣悪であると判断されたときは、変調多値数が小さく信頼度が高い変調方式(伝搬状況が最悪のときは、ダミーデータ伝送)を指示し、他方、伝搬路状況が比較的良好であると判断されたときは、変調多値数が大きく信頼度が比較的低い変調方式を指示する。 That is, the modulation level control circuit 4 for performing adaptive modulation, when channel condition is judged to be relatively poor, the modulation level is small reliability is high modulation scheme (propagation conditions are the worst when instructs the dummy data transmission), while when the channel condition is determined to be relatively good, the modulation level is larger reliability indicating the relatively low modulation scheme. このようにして伝搬状況に応じた適応変調を行うことにより、ビットエラーレート等により見極められる情報伝送の質が向上することになる。 By performing this way adaptive modulation according to propagation conditions, information transmission quality to be ascertained is improved by a bit error rate or the like.

【0007】 [0007]

【発明が解決しようとする課題】ところで上記のような従来の多値適応変調無線装置においては、上記送信電力増幅回路7として、電源効率の点で劣るバックオフの大きな線形電力増幅器(すなわちA級電力増幅器)を用いている。 In [0008] Meanwhile the conventional multi-level adaptive modulation wireless device as described above, as the transmission power amplifying circuit 7, a large linear power amplifier backoff inferior in terms of power efficiency (i.e. class A and using the power amplifier). バックオフの大きな線形電力増幅器を用いる理由は、バックオフの小さい飽和電力増幅器(たとえば、 The reason for using a large linear power amplifier backoff, the backoff small saturation power amplifier (e.g.,
AB級電力増幅器)を用いた場合には、変調波の包絡線変動が大きいときに、スペクトラム歪みが発生し、この歪みは多値QAMのような線形変調では送信信号の振幅や位相の歪みを引起し、このような送信信号を受信した受信側では、送信信号からの送信情報の抽出は、極めて困難になるからである。 When using class AB power amplifier), when the envelope fluctuation of the modulated wave is large, the spectrum distortion occurs, the distortion of amplitude or phase of the transmission signal is a linear modulation such as this distortion multilevel QAM and causing, at the receiving side that has received such a transmission signal, extracts the transmission information from the transmission signal, because is extremely difficult. 図6は、上記理由を、一層、具体的に説明するためのものであり、同図の(a)は、送信電力増幅器としてバックオフが大きいA級電力増幅器を用いた場合の送信スペクトラムを示し、また同図の(b)は、送信電力増幅増幅器としてバックオフが小さい例えばAB級電力増幅器を用いた場合の送信スペトクラムを示している。 6, the reason more is for specifically explaining, in Fig. (A) shows the transmission spectrum in the case of using the back-off large class-A power amplifier as the transmission power amplifier and in FIG. (b) shows the transmission Supetokuramu in the case of using the back-off is small for example AB class power amplifier as the transmission power amplification amplifier. 上記(a)と(b)の送信スペクトラムを比較すると(b)の方は(バックオフが小さい方)は、(a)の方(バックオフが大きい方)に比べてサイドローブが盛上がっており、歪みが発生していることが分かる。 Compared above (a) and the transmission spectrum of the (b) direction of (b) is (Write backoff is small), and the raised sidelobes than the (a) towards (towards backoff is large) cage, it can be seen that distortion has occurred. この歪みの有無が、同図の(c)および(d)に示すコンステレーション歪みの有無すなわち送信信号の振幅や位相の歪みの有無につながるのである。 The presence or absence of this strain is the result of the presence of absence i.e. distortion of amplitude or phase of the transmission signal of the constellation distortions shown in the same figure (c) and (d).
そして、上記(d)に示すようなコンステレーション歪みを持つ送信信号すなわち振幅や位相が歪んでいる送信信号から送信情報を抽出することは極めて困難になるのである。 Then, it is becoming very difficult to extract transmit information from the transmission signal is distorted transmission signal, that is amplitude or phase with constellation distortions shown in above (d).

【0008】以上のような理由により、従来、上記送信電力増幅回路7としてはバックオフの大きな線形電力増幅を用いてきたが、これは、上述のように電源効率が悪く、電力消費といった面で問題がある。 [0008] By the above reasons, conventionally, as the transmission power amplifying circuit 7 has been using a large linear power amplifier backoff, which is the power efficiency as described above is poor in terms such as power consumption There's a problem.

【0009】本願発明は、上述のような事情に鑑みて、 [0009] The present invention, in view of the circumstances as described above,
なされたものであり、送信電力増幅回路を幾分でも電源効率のよいものにすることができる多値適応変調無線装置の提供を目的とする。 It has been made, and an object thereof is to provide a multi-level adaptive modulation wireless device can be a transmission power amplifying circuit having good power efficiency somewhat.

【0010】 [0010]

【課題を解決するための手段】請求項1の発明では、変調に際しては伝搬路状況に応じて変調多値数の異なる複数の変調方式のいずれかを選択し、選択した変調方式での変調動作を行なう多値適応変調無線装置を以下のように構成した。 In SUMMARY OF to the invention of claim 1, select one of a plurality of modulation schemes with different modulation levels according to channel conditions. Before modulation, the modulation operation on the selected modulation scheme the multi-level adaptive modulation wireless device that performs configured as follows.

【0011】後述の制御回路の制御の下に、送信データを指定された変調多値数の変調方式のシンボルにマッピングして、対応する複素ベースバンド信号を送出するシンボルマッピング回路と、上記シンボルマッピング回路よりの複素ベースバンド信号に基づき、直交変調を行なう直交変調回路と、後述の制御回路の制御の下に、上記直交変調回路よりの変調波の電力増幅を、指定されたバックオフで行なう送信電力増幅回路と、受信信号に対して検波および復号の処理を加えて受信データを得て、この受信データを出力する受信回路と、上記受信回路から受信ベースバンド信号若しくは受信レベル情報の一方、 [0011] Under the control of the control circuit to be described later, by mapping the symbols of a given modulation level of the modulation scheme to transmit data, and symbol mapping circuit for sending a corresponding complex baseband signal, the symbol mapping based on the complex baseband signal from the circuit, a quadrature modulation circuit which performs quadrature modulation, under the control of the control circuit to be described later, the power amplification of the modulated wave from the quadrature modulation circuit is performed at the specified backoff transmission a power amplifier circuit, to obtain received data in addition to processing of detection and decoding on the received signal, and a reception circuit for outputting the received data, one of the received baseband signal or the reception level information from the receiver circuit,
又はそれら両方を取込み、この取込んだ信号等に基づき、伝搬路状況を推定して、推定結果である推定信号を送出する伝搬路推定回路と、上記伝搬路推定回路よりの推定信号が、伝搬路状況は比較的悪いと推定するものであるときには、上記シンボルマッピング回路に対して、 Or they capture both, based on the taken-signal, etc., by estimating the channel state, a channel estimation circuit for delivering an estimated signal is the estimated result, the estimated signal from the channel estimation circuit, propagation when road conditions are those estimated as relatively poor, with respect to the symbol mapping circuit,
変調多値数が4以下でコンステレーション(ディジタル直交変調の信号配置図)の零点を交差しないように構成した変調方式を指定すると共に、上記送信電力増幅回路に対して、小さいバックオフでの動作を指定し、他方、 While specifying a modulation scheme modulation level is configured so as not to intersect the zero point of the constellation (signal arrangement diagram of a digital quadrature modulation) by 4 or less, with respect to the transmission power amplifying circuit, the operation of a small backoff specified, on the other hand,
上記推定信号が、伝搬路状況は比較的良いと推定するものであるときには、上記シンボルマッピング回路に対して、変調多値数が4を越える変調方式を指定すると共に、上記送信電力増幅回路に対して、線形領域のみを利用する大きなバックオフでの動作を指定する制御回路とを備える構成とした。 The estimated signal, when the channel state is for relatively good estimated, relative to the symbol mapping circuit, as well as specifying a modulation scheme modulation level exceeds 4, to the transmission power amplifying circuit Te, and a configuration and a control circuit for designating the operation of a large back-off using only the linear region.

【0012】請求項2の発明では、請求項1の発明に係る多値適応変調無線装置の上記制御回路を、変調多値数が4以下の変調方式としては、π/2シフトBPSK [0012] In the present invention of claim 2, the control circuit of the multi-level adaptive modulation wireless device according to the invention of claim 1, as a modulation multi-level number is 4 or less of the modulation scheme, [pi / 2 shift BPSK
(π/2シフト2値位相変調)又はπ/4シフトQPS ([Pi / 2 shift binary phase modulation) or [pi / 4 shift QPS
K(π/4シフト直交位相変調)を選択的に指定し、変調多値数が4を越える変調方式としては、π/4シフトQPSKとASK(振幅変調)とを組合わせた方式又はスター16QAM(スター16値直交振幅変調)を選択的に指定する回路とした。 K selectively specify ([pi / 4-shift quadrature phase modulation), as a modulation scheme modulation level exceeds 4, [pi / 4 shift QPSK and ASK (amplitude modulation) and the combinatorial scheme or star 16QAM and the circuit for selectively specify (Star 16 quadrature amplitude modulation).

【0013】請求項3の発明では、請求項2の発明に係る多値適応変調無線装置の上記制御回路を、変調多値数が4を越える変調方式の1つとしてπ/4シフトQPS [0013] In the present invention of claim 3, the control circuit of the multi-level adaptive modulation wireless device according to the invention of claim 2, [pi / 4 shift QPS as one of modulation schemes modulation level exceeds 4
KとASKとトレリス符号化変調とを組合わせた変調方式をも指定する回路とした。 And the circuit also specify the modulation scheme which combined the K and ASK and trellis coded modulation.

【0014】請求項4の発明では、請求項1の発明に係る多値適応変調無線装置の上記制御回路を、多値数が4 [0014] In the present invention of claim 4, the control circuit of the multi-level adaptive modulation wireless device according to the invention of claim 1, multi-level number is 4
以下の変調方式としては、π/2シフトBPSK又はO The following modulation scheme, [pi / 2 shift BPSK or O
QPSK(オフセット直交位相変調)を選択的に指定し、変調多値数が4を越える変調方式としては、OQP Selectively specify QPSK (offset quadrature phase modulation), as a modulation scheme modulation level exceeds 4, OQP
SKとASKを組合わせた方式又は16QAM(16値直交振幅変調)を選択的に指定する回路とした。 SK and method a combination of ASK or 16QAM (16 Quadrature Amplitude Modulation) was selectively specify that circuit.

【0015】 [0015]

【発明の実施の形態】以下、本願発明の実施の形態により、本願発明を具体的に説明する。 DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the embodiments of the present invention will be specifically described the present invention. 図1は、本願発明の実施の形態に係る多値適応変調無線装置の構成を示すものである。 Figure 1 shows a configuration of a multilevel adaptive modulation radio apparatus according to the embodiment of the present invention. 同図において、従来例を示す前記図4における回路部と同一符号が付されている回路部は、図4における回路部と同一構成および機能を備えるものとなっている。 In the figure, circuit portions same reference numerals and the circuit portion in FIG. 4 showing a conventional example are assigned, it has become one with the same configuration and function as the circuit portion in FIG. すなわち、図4における変調レベル制御回路4および送信電力増幅回路7は、図1においては、それぞれ制御回路14および送信電力増幅回路17に変更されているが、他の回路部については、概ね変更はない。 That is, the modulation level control circuit 4 and the transmission power amplifying circuit 7 in FIG. 4, in FIG. 1 has been changed to the control circuit 14 and transmit power amplifier circuit 17, the other circuit portion, is substantially modified Absent.

【0016】図1において、制御回路14は、伝搬路推定回路3からの前記推定信号を入力し、この信号に基づいて、その時点の伝搬路状況で(すなわち推定した伝搬路状況下で)誤り率を所定値以下に保ちつつ、最大の情報速度が得られる変調方式を選択して、この変調方式でのマッピングを指示する制御信号をシンボルマッピング回路5に送出すると共に、送信電力増幅回路17にも制御信号を送ってこの送信電力増幅回路17の増幅動作におけるバックオフの大きさを指示する回路になっている。 [0016] In FIG 1, the control circuit 14 inputs the estimated signal from the channel estimation circuit 3, based on this signal, the propagation path conditions at the time (i.e. under channel availability estimated) errors while keeping the rate below a predetermined value, and selects a modulation scheme maximum information rate is obtained, it sends out a control signal for instructing the mapping in the modulation scheme symbol mapping circuit 5, the transmission power amplifying circuit 17 It has a circuit for indicating the magnitude of the back-off even sends a control signal in the amplification operation of the transmission power amplifying circuit 17. また図1における送信電力増幅回路17は、直交変調回路6からの変調波を入力して、これを制御回路14 The transmission of Figure 1 the power amplifier circuit 17 inputs the modulated wave from the quadrature modulation circuit 6, controls this circuit 14
によって指示された大きさのバックオフでの電力増幅を行なって送出する回路部となっている。 It has a circuit portion for sending by performing power amplification at backoff magnitude indicated by.

【0017】以上のように構成された本実施の形態においては、伝搬路推定回路3は伝搬路状況を悪い方から順にA、B、C、D、Eの5段階に分けて評価する。 In the present embodiment configured as described above, channel estimation circuit 3 A from the worse the channel conditions in order, B, C, D, to evaluate in five stages of E. 例えば伝搬路状況が最も悪く評価がAであるときは、このA For example, when the propagation condition is worst rating A, the A
を示す推定信号を伝搬路推定回路3から与えられた制御回路14は、シンボルマッピング回路5に対し変調方式として図2の(a)に示すπ/2シフトBPSKを指示すると共に、送信電力増幅回路17に対しては、バックオフを小さくした状態での増幅動作を指示する。 Channel estimation control circuit supplied from circuit 3 an estimated signal indicating the 14 instructs the [pi / 2 shift BPSK shown in FIG. 2 (a) as a modulation scheme to symbol mapping circuit 5, transmission power amplifying circuit for 17 instructs the amplification operation while reducing the back-off. また伝搬路状況が比較的悪く、評価がBのときは、このBを示す推定信号を伝搬路推定回路3から与えられた制御回路14はシンボルマッピング回路5に対し、変調方式として、図2の(b)に示すπ/4シフトQPSKを指示すると共に、送信電力増幅回路17に対してはバックオフを小さくした状態での増幅動作を指示する。 The channel condition is relatively poor, when evaluation is B, the control circuit 14 that received estimated signal indicating the B from the channel estimation circuit 3 to the symbol mapping circuit 5, as the modulation method, in FIG. 2 (b) instructs the [pi / 4 shift QPSK shown in, for instructing the amplification operation in a state of reduced back-off for the transmission power amplifying circuit 17.

【0018】また、伝搬路状況が比較的良好で評価がC [0018] In addition, the propagation path situation is relatively good evaluation is C
のときは、このCを示す推定信号を伝搬路推定回路3から与えられた制御回路14はシンボルマッピング回路5 When the control circuit 14 that received estimated signal indicating the C from the channel estimation circuit 3 symbol mapping circuit 5
に対し、変調方式として、図2の(c)に示すπ/4シフトQPSKとASKとTCM(トレリス符号化変調) Respect, as the modulation scheme, shown in FIGS. 2 (c) π / 4 shift QPSK and ASK and TCM (Trellis Coded Modulation)
を組合わせたものを指示すると共に、送信電力増幅回路17に対しては、バックオフを大きくした状態での増幅動作を指示する。 Instructs what a combination of, for the transmission power amplifying circuit 17, and instructs the amplification operation while increasing the back-off. 評価がDのときは、制御回路14はシンボルマッピング回路5に対し、変調方式として、図2 When evaluation and D, the control circuit 14 to the symbol mapping circuit 5, as the modulation method, Figure 2
の(d)に示すπ/4シフトQPSKとASKとを組合わせたものを指示すると共に、送信電力増幅回路17に対しては、バックオフを大きくした状態での増幅動作を指示する。 It instructs what a combination of the (d) are shown [pi / 4 shift QPSK and ASK, with respect to the transmission power amplifying circuit 17, and instructs the amplification operation while increasing the back-off. そして、伝搬状況が極めて良好で、評価がE Then, propagation conditions are very good, evaluation is E
のときは、制御回路14はシンボルマッピング回路5に対して、変調方式として、図2の(e)に示すスター型16QAMを指示すると共に、送信電力増幅回路17に対してはバックオフを大きくした状態での増幅動作を指示する。 When the control circuit 14 for the symbol mapping circuit 5, as a modulation system, instructs a star 16QAM shown in the FIG. 2 (e), the was increased back-off for the transmission power amplifying circuit 17 instructing the amplification operation in the state.

【0019】以上のように、この実施の形態においては、評価がAまたはBの場合のように伝搬路状況が良くない場合は、変調方式を多値数が小さく且つコンステレーションの零点を交差しないものとし、その上で送信電力増幅回路17のバックオフを小さくしてこの送信電力増幅回路17にAB級増幅動作をさせて高電源効率を実現している。 [0019] As described above, in this embodiment, evaluation is if poor propagation path condition as in the case of A or B, not the modulation scheme crosses the zero point of the multi-level number small and constellations and things, which achieves high power efficiency by a class AB amplifier operates in the transmission power amplifying circuit 17 to reduce the back-off of the transmission power amplifying circuit 17 thereon. この場合、送信電力増幅回路17のバックオフを小さくできるのは、上記変調方式で変調した変調波の振幅には変調情報が含まれないためである。 In this case, can be reduced back-off of the transmission power amplifying circuit 17, the amplitude of the modulated wave modulated by the modulation method is because it does not contain modulated information. また、 Also,
評価がC、DまたはEの場合のように伝搬路状況が良いときは、従来の多値適応変調無線装置と同様で、この良好の伝搬路状況を活用するために変調多値数の大きな変調方式を用い、送信電力増幅回路17にはバックオフの大きな状態での増幅動作(例えばA級増幅動作)をさせている。 When evaluation is C, propagation path condition as in the case of D or E is good, similar to the conventional multi-level adaptive modulation wireless device, large modulation of modulation level to take advantage of this good channel state used method, thereby amplifying operation of a large state of the back-off (e.g. class a amplification operation) to transmit power amplifier circuitry 17. これは、変調多値数の大きな変調方式で変調した変調波では、振幅にも変調情報が含まれるので、線形領域での増幅動作の確保が必要だからである(すなわち従来例において送信電力増幅回路7にA級増幅動作をさせていた理由と同様の理由である)。 This is because, in the modulated wave modulated by a large modulation method of the modulation multi-level number, since the amplitude is included modulated information, because we need to secure the amplification operation in the linear region (i.e. transmission in the conventional example power amplifier 7 which is the same reason as was allowed to a class amplification operation).

【0020】以上のように、この実施の形態によれば、 [0020] As described above, according to this embodiment,
伝搬路状況が比較的良くなく、信頼度を重視し、1シンボル当りのビット数を押さえて伝送を行なっているときには、送信電力増幅回路17のバックオフを小さくして、この送信電力増幅回路17の電源効率を高いものとすることができる。 Channel condition is no relatively well, emphasizes reliability, while doing transmission pressing the number of bits per symbol, to reduce the back-off of the transmission power amplifying circuit 17, the transmission power amplifying circuit 17 it can be the power efficiency high.

【0021】なお、本願発明は、上記実施の形態に限定されるものでなく、本願発明の範囲で種々応用変形が可能である。 [0021] Incidentally, the present invention is not limited to the above embodiments and can be variously applied modified within the present invention. 例えば、上記実施の形態では伝搬路状況をA、B、C、D、Eの5段階で評価し、この評価に応じて、図2に示す各変調方式を切替えて利用するものであったが、伝搬路状況を悪い方から順に、A、B、C、D For example, in the above embodiment to evaluate the channel conditions A, B, C, D, in five stages of E, according to the evaluation, but was to use by switching each modulation scheme shown in FIG. 2 , in order of bad channel conditions, a, B, C, D
の4段階で評価し、この評価に応じて、図3に示す各変調方式を切替えて利用するようにしてもよい。 Was evaluated in four stages of, depending on the evaluation, it may be utilized by switching each modulation scheme shown in FIG. すなわち評価がAのときはπ/2シフトBPSK、評価がBのときはOQPSK、評価がCのときはOQPSKとASK That is [pi / 2 shift BPSK when the evaluation is A, OQPSK when evaluation is B, OQPSK and ASK when the evaluation is C
を組合せたもの、評価が最良でDのときは16QAMといった具合に切替えて利用するようにしてもよい。 A combination of the evaluation may also be utilized by switching to so on 16QAM when the D best. なお、このような変調方式の切替えにおいても、伝搬路状況が悪いときは、コンステレーションの零点を交差しないように構成した変調多値数の小さい変調方式を利用しているので、送信電力増幅回路17をバックオフの小さい状態で利用でき、この送信電力増幅回路17の電源効率を高いものとすることができる。 Also in the switching of such a modulation method, when a bad channel status, the use of the small modulation method modulation level configured so as not to intersect the zero point of the constellation, the transmission power amplifying circuit 17 available in a small state of back-off, it is possible to heighten the power efficiency of the transmission power amplifying circuit 17.

【0022】 [0022]

【発明の効果】以上詳述したように、本願発明によれば、送信電力増幅回路の電源効率を良くすることができる多値適応変調無線装置の提供を可能とする。 As described above in detail, according to the present invention enables to provide a multi-level adaptive modulation wireless device capable of improving the power efficiency of the transmission power amplifying circuit.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本願発明の実施の一形態の回路構成を示す図である。 1 is a diagram showing a circuit configuration of an embodiment of the present invention.

【図2】上記実施の形態において切替えて利用される変調方式を示す図である。 2 is a diagram showing the modulation scheme employed by switching in the above embodiment.

【図3】応用変形例において切替えて利用される変調方式を示す図である。 3 is a diagram showing the modulation scheme employed by switching the applied modified example.

【図4】従来例の回路構成を示す図である。 4 is a diagram showing a circuit configuration of a conventional example.

【図5】従来例において切替えて利用される変調方式を示す図である。 5 is a diagram showing the modulation scheme employed by switching in the conventional example.

【図6】従来例においてA級電力増幅器が用いられる理由を説明するための図である。 6 is a diagram for explaining the reason why a class A power amplifier in the conventional example is used.

【符号の説明】 DESCRIPTION OF SYMBOLS

1 送信アンテナ 2 受信部 3 伝搬路推定回路 4 変調レベル制御回路 5 シンボルマッピング回路 6 直交変調回路 7 送信電力増幅回路 14 制御回路 17 送信電力増幅回路 1 transmitting antenna 2 receiving unit 3 channel estimation circuit 4 modulation level control circuit 5 symbol mapping circuit 6 quadrature modulation circuit 7 transmission power amplifying circuit 14 control circuit 17 transmit power amplifier

Claims (4)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】 変調に際しては、伝搬路状況に応じて、 [Claim 1] In modulation according to channel conditions,
    変調多値数の異なる複数の変調方式のいずれかを選択し、選択した変調方式での変調動作を行なう多値適応変調無線装置において、 後述の制御回路の制御の下に、送信データを指定された変調多値数の変調方式のシンボルにマッピングして、対応する複素ベースバンド信号を送出するシンボルマッピング回路と、 上記シンボルマッピング回路よりの複素ベースバンド信号に基づき、直交変調を行なう直交変調回路と、 後述の制御回路の制御の下に、上記直交変調回路よりの変調波の電力増幅を、指定されたバックオフで行なう送信電力増幅回路と、 受信信号に対して検波および復号の処理を加えて受信データを得て、この受信データを出力する受信回路と、 上記受信回路から受信ベースバンド信号若しくは受信レベル情報の一方、又はそ Select one of a plurality of different modulation schemes modulation level of, in the multi-level adaptive modulation wireless device for performing the modulation operation on the selected modulation scheme, under the control of the control circuit to be described later, the designated transmission data was mapped to a symbol of the modulation level of a modulation scheme, a symbol mapping circuit for sending a corresponding complex baseband signal, and a quadrature modulation circuit based on the complex baseband signal from the symbol mapping circuit performs quadrature modulation , under the control of the control circuit to be described later, the power amplification of the modulated wave from the quadrature modulation circuit, in addition the transmission power amplifying circuit for performing a specified backoff, the process of detection and decoding on the received signals to obtain received data, and a reception circuit for outputting the received data, one of the received baseband signal or the reception level information from the receiver circuit, or its ら両方を取込み、この取込んだ信号等に基づき、伝搬路状況を推定して、推定結果である推定信号を送出する伝搬路推定回路と、 上記伝搬路推定回路よりの推定信号が、伝搬路状況は比較的悪いと推定するものであるときには、上記シンボルマッピング回路に対して、変調多値数が4以下で且つコンステレーションの零点を交差しないように構成した変調方式を指定すると共に、上記送信電力増幅回路に対して、小さいバックオフでの動作を指定し、他方、上記推定信号が、伝搬路状況は比較的良いと推定するものであるときには、上記シンボルマッピング回路に対して、変調多値数が4を越える変調方式を指定すると共に、上記送信電力増幅回路に対して、線形領域のみを利用する大きなバックオフでの動作を指定する制御回路とを備え Capture both Luo, based on the taken-signal, etc., by estimating the channel state, a channel estimation circuit for delivering an estimated signal is the estimated result, the estimated signal from the channel estimation circuit, the channel when conditions are those estimated as relatively poor, with respect to the symbol mapping circuit, the configuration specified modulation scheme as the modulation level is not and crosses the zero point of the constellation in 4 below, the transmission to the power amplifier circuit, to specify the behavior of a small back-off, while the estimated signal, when the channel state is for relatively good estimated, relative to the symbol mapping circuit, modulation level with specifying the modulation method number exceeds 4, with respect to the transmission power amplifying circuit, and a control circuit for designating the operation of a large back-off to use only the linear region ことを特徴とする多値適応変調無線装置。 Multilevel adaptive modulation wireless device, characterized in that.
  2. 【請求項2】 上記制御回路は、変調多値数が4以下の変調方式としては、π/2シフトBPSK又はπ/4シフトQPSKを選択的に指定し、変調多値数が4を越える変調方式としては、π/4シフトQPSKとASKとを組合わせた方式又はスター16QAMを選択的に指定する回路であることを特徴とする請求項1記載の多値適応変調無線装置。 Wherein said control circuit includes, as the modulation level is 4 or less of the modulation scheme, [pi / 2 selectively specify a shift BPSK or [pi / 4 shift QPSK, the modulation level exceeds 4 modulation the method, [pi / 4 shift QPSK and the multi-level adaptive modulation wireless device of claim 1, wherein the the combinatorial scheme or star 16QAM and ASK is a circuit for designating selectively.
  3. 【請求項3】 上記制御回路は、変調多値数が4を越える変調方式の1つとしてπ/4シフトQPSKとASK Wherein said control circuit, one as [pi / 4 shift QPSK and ASK modulation scheme modulation level exceeds 4
    とトレリス符号化変調とを組合わせた変調方式をも指定する回路であることを特徴とする請求項2記載の多値適応変調無線装置。 A multi-level adaptive modulation wireless device according to claim 2, characterized in that the circuit also specify the modulation scheme which combined the trellis coded modulation.
  4. 【請求項4】 上記制御回路は、変調多値数が4以下の変調方式としては、π/2シフトBPSK又はOQPS Wherein said control circuit includes, as the modulation level is 4 or less of the modulation scheme, [pi / 2 shift BPSK or OQPS
    Kを選択的に指定し、変調多値数が4を越える変調方式としては、OQPSKとASKを組合わせた方式又は1 K selectively specify, as the modulation scheme modulation level exceeds 4, method a combination of OQPSK and ASK or 1
    6QAMを選択的に指定する回路であることを特徴とする請求項1記載の多値適応変調無線装置。 Multilevel adaptive modulation radio apparatus according to claim 1, characterized in that the circuit for selectively specify 6QAM.
JP7260928A 1995-09-14 1995-09-14 Multilevel adaptative modulation radio device Pending JPH0983600A (en)

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