【０００１】[0001]
【産業上の利用範囲】本発明はスペクトラム拡散通信方
式に関するもので、特に４位相角変調を併用する場合
に、伝送品質を改善するのに有効な方式である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication system, and particularly to a system that is effective for improving transmission quality when four-phase angle modulation is used together.
【０００２】[0002]
【従来の技術】スペクトラム拡散通信（以下ＳＳ通信と
略す）は、送信側においては疑似ランダム信号（以下Ｐ
Ｎ信号と略す）を掛け合わせることによって送信信号を
広い周波数帯域に拡散し、受信側においては前記と同じ
ＰＮ信号を受信信号に掛け合わせてＰＮ信号同志を打ち
消すことによって、元の狭帯域の信号に逆拡散する方式
である。３図−ａはＭ系列のＰＮ符号の自己相関特性を
示すもので、３図−ｂはＭ系列の異なる二つのＰＮ符号
間の相互相関特性の例を示すものであるが、受信側のＰ
Ｎ信号が送信側のと同じ符号であれば、符号の位相が一
致した時に３図−ａのピーク値に相当する逆拡散出力が
得られるのに対し、送信側と受信側のＰＮ信号が異なる
符号であれば３図−ｂに示すように、位相に関わらず大
きな逆拡散出力が現れない。従って、受信信号に二つの
異なる符号で拡散されたＳＳ信号が混じりあっていて
も、一方の符号で逆拡散した逆拡散出力への、他方の符
号で拡散されたＳＳ信号の影響は小さいので、異なる符
号を用いることによって、同じ周波数帯域を共用する符
号多重という性質がある。2. Description of the Related Art Spread spectrum communication (hereinafter abbreviated as SS communication) is a pseudo random signal (hereinafter referred to as P
N is abbreviated as N signal) to spread the transmission signal over a wide frequency band. On the receiving side, the same PN signal as described above is multiplied by the received signal to cancel out the PN signal, thereby obtaining the original narrowband signal. Is a method of despreading. FIG. 3A shows the autocorrelation characteristic of the M sequence PN code, and FIG. 3B shows an example of the cross correlation characteristic between two different PN codes of the M sequence.
If the N signal has the same code as that on the transmitting side, a despread output corresponding to the peak value in FIG. 3A is obtained when the phases of the codes match, whereas the PN signal on the transmitting side and the PN signal on the receiving side are different. If it is a code, a large despread output does not appear regardless of the phase as shown in FIG. 3-b. Therefore, even if the SS signal spread with two different codes is mixed in the received signal, the influence of the SS signal spread with the other code on the despread output despread with one code is small, By using different codes, there is a characteristic of code multiplexing sharing the same frequency band.
【０００３】４位相角変調（以下ＱＰＳＫと略す）は、
互いに直交する二つの搬送波に掛け合わされた信号が、
互いに妨害を与えずに復調できる性質を利用したもので
ある。４図−ａはＱＰＳＫの位相と復調出力の関係を示
したもので、（Ｄ１・ＳＩＮθ＋Ｄ２・ＣＯＳθ）で現
されるＱＰＳＫ信号に、受信側で再生した互いに直交す
るＳＩＮθとＣＯＳθをそれぞれ掛け合わせることによ
り、Ｄ１とＤ２を独立して互いに妨害を与えずに復調で
きる。ＱＰＳＫは互いに直交する二つの搬送波を使用し
て２位相角変調（以下ＢＰＳＫと略す）することによ
り、二つのＢＰＳＫ信号を同じ周波数帯域を使って伝送
する多重化方式であると言うことができる。[0003] Four phase angle modulation (hereinafter abbreviated as QPSK) is
The signal multiplied by two mutually orthogonal carriers is
This utilizes the property of being able to demodulate without interfering with each other. FIG. 4A shows the relationship between the phase of QPSK and the demodulated output. The QPSK signal represented by (D1 · SINθ + D2 · COSθ) is multiplied by the mutually orthogonal SINθ and COSθ reproduced on the receiving side. Thus, D1 and D2 can be demodulated independently without interfering with each other. It can be said that QPSK is a multiplexing method for transmitting two BPSK signals using the same frequency band by performing two-phase angle modulation (hereinafter abbreviated as BPSK) using two orthogonal carrier waves.
【０００４】このＳＳ−ＱＰＳＫ方式の一例を図２に示
す。図２において発振器１は搬送波２１を発生し、移相
器２は搬送波２１から搬送波２１に対して９０度位相の
ずれた搬送波２２をつくる。乗算器３はデータ列２３を
搬送波２１に掛け合わせてＢＰＳＫ信号２５をつくり、
乗算器４はデータ列２４を搬送波２２に掛け合わせてＢ
ＰＳＫ信号２６をつくる。乗算器８はＢＰＳＫ信号２５
に第１のＰＮ信号４１を掛け合わせてＳＳ信号３０をつ
くり、乗算器９はＢＰＳＫ信号２６に前記第１のＰＮ信
号４１と異なる符号の第２のＰＮ信号４２を掛け合わせ
てＳＳ信号３１をつくる。加算器１０は二つのＳＳ信号
３０と３１を足し合わせて送信信号３２をつくる。送信
信号３２は伝送路１１を通って受信信号３３となる。FIG. 2 shows an example of the SS-QPSK system. In FIG. 2, the oscillator 1 generates a carrier wave 21, and the phase shifter 2 generates a carrier wave 22 having a phase shifted from the carrier wave 21 by 90 degrees with respect to the carrier wave 21. Multiplier 3 multiplies data sequence 23 by carrier 21 to form BPSK signal 25,
The multiplier 4 multiplies the data sequence 24 by the carrier wave 22 to generate B
Generate the PSK signal 26. The multiplier 8 has a BPSK signal 25
Is multiplied by a first PN signal 41 to generate an SS signal 30. The multiplier 9 multiplies the BPSK signal 26 by a second PN signal 42 having a different sign from the first PN signal 41 to generate an SS signal 31. to make. The adder 10 adds the two SS signals 30 and 31 to generate a transmission signal 32. The transmission signal 32 passes through the transmission path 11 and becomes a reception signal 33.
【０００５】受信側では、前記第１のＰＮ信号４１及び
第２のＰＮ信号４２とそれぞれ同符号で位相の同期した
第３のＰＮ信号４３と第４のＰＮ信号４４とを作成し、
乗算器１５で受信信号３３に前記第３のＰＮ信号３５を
掛け合わせてＢＰＳＫ信号３７を得る。また乗算器１６
で受信信号３３に前記第４のＰＮ信号３６を掛け合わせ
てＢＰＳＫ信号３８を得る。ＢＰＳＫ復調器１７はＢＰ
ＳＫ信号３７を復調して復調データ列３９を得る。ＢＰ
ＳＫ復調器１８はＢＰＳＫ信号３７を復調して復調デー
タ列４０を得る。[0005] On the receiving side, a third PN signal 43 and a fourth PN signal 44 which are synchronized with the first PN signal 41 and the second PN signal 42 and have the same signs and phases, respectively, are created.
The multiplier 15 multiplies the reception signal 33 by the third PN signal 35 to obtain a BPSK signal 37. The multiplier 16
Then, the received signal 33 is multiplied by the fourth PN signal 36 to obtain a BPSK signal 38. BPSK demodulator 17 is BP
The SK signal 37 is demodulated to obtain a demodulated data string 39. BP
The SK demodulator 18 demodulates the BPSK signal 37 to obtain a demodulated data sequence 40.
【０００６】すなわち、ＳＳ−ＱＰＳＫ方式は搬送波に
位相が互いに直交する二つのＢＰＳＫ信号２５、２６
を、異なる符号の二つのＰＮ信号４１、４２でおのおの
拡散する方式であり、異なるＰＮ信号で拡散された信号
が混入してきても大きな妨害を受けない性質から、ＰＮ
信号４１と同じ符号であるＰＮ信号４３で逆拡散する
と、一方のＢＰＳＫ信号２５に対応したＢＰＳＫ信号３
７が得られ、ＰＮ信号４２と同符号のＰＮ信号４４で逆
拡散すると、もう一方のＢＰＳＫ信号２６に対応したＢ
ＰＳＫ信号３８が得られる。このようにＳＳ−ＱＰＳＫ
では逆拡散によって二つの搬送波が分離できるので、Ｂ
ＰＳＫの方式で個々に復調ができる特徴がある。That is, in the SS-QPSK method, two BPSK signals 25 and 26 whose phases are orthogonal to each other on a carrier wave.
Is spread by two PN signals 41 and 42 of different codes, and since PN signals are not greatly interfered even if signals spread by different PN signals are mixed,
When despreading with the PN signal 43 having the same code as the signal 41, the BPSK signal 3 corresponding to one BPSK signal 25 is obtained.
7 is obtained and despread with a PN signal 44 having the same code as the PN signal 42, a B signal corresponding to the other BPSK signal 26 is obtained.
A PSK signal 38 is obtained. Thus, SS-QPSK
Since the two carriers can be separated by despreading,
There is a feature that demodulation can be performed individually by the PSK method.
【０００７】[0007]
【発明が解決しようとする問題点】４図は、ＱＰＳＫ信
号の二つの搬送波が相互に与える妨害を示したもので、
送信または受信機の搬送波の９０度移相器の位相誤差
や、受信機の搬送波再生回路の位相誤差や、伝送路上や
送受信回路内で生じる波形ひずみなどによって、復調し
ようとする位相に対する他方の搬送波の位相が９０度か
らずれていると、復調した信号に他方の信号が混入する
ことになる。また、受信信号のＳ／Ｎが悪いと搬送波再
生が不安定になり、位相誤差が大きくなることが知られ
ている。FIG. 4 shows the interference of two carriers of a QPSK signal with each other.
The other carrier with respect to the phase to be demodulated due to the phase error of the 90-degree phase shifter of the carrier of the transmission or receiver, the phase error of the carrier recovery circuit of the receiver, or the waveform distortion generated on the transmission line or in the transmission / reception circuit. Is shifted from 90 degrees, the other signal is mixed with the demodulated signal. Also, it is known that if the S / N of the received signal is poor, carrier wave reproduction becomes unstable and the phase error increases.
【０００８】ＳＳ通信は伝送路上で混入した妨害信号を
逆拡散によって抑圧できる性質がり、この性質を利用し
て劣悪な通信路に適用されることが多く、ＳＳ−ＱＰＳ
Ｋでも２図に示すように逆拡散によってＳ／Ｎを改善し
てからデータを復調する構成をとる。ところが逆拡散に
よるＳ／Ｎの改善において最も問題のある妨害波は別の
ＳＳ信号であり、全く同じ周波数帯域の信号は符号間の
相互相関特性によってしか妨害の抑圧ができず、３図−
ｂに示すように異符号間の相関は必ずしも小さいとは言
えない、特にＳＳ−ＱＰＳＫでは異なる符号で拡散され
た信号が同じ電力で送信されるので、受信側での逆拡散
による妨害抑圧効果が十分でないと、後段の復調回路に
おけるＳ／Ｎが悪くなり、復調に誤りが生じて通信回線
としての伝送品質が悪化する恐れがある。[0008] The SS communication has a property that an interfering signal mixed on a transmission path can be suppressed by despreading, and it is often applied to a poor communication path by utilizing this property.
As shown in FIG. 2, even for K, the data is demodulated after the S / N is improved by despreading. However, the most problematic interference wave in the improvement of S / N by despreading is another SS signal, and signals in the same frequency band can be suppressed only by cross-correlation characteristics between codes.
As shown in b, the correlation between different codes is not always small. In particular, in SS-QPSK, signals spread with different codes are transmitted with the same power, so that the interference suppression effect due to despreading on the receiving side is reduced. If it is not sufficient, the S / N in the demodulation circuit at the subsequent stage will deteriorate, and an error will occur in demodulation, and the transmission quality as a communication line may deteriorate.
【０００９】逆拡散する符号に対して同符号と異符号の
二種類のＰＮ信号で拡散されたＳＳ信号を、同じ比率で
足し合わせて逆拡散する場合の相関特性は、３図−ａと
３図−ｂの特性を平均した特性になる。従って、伝送経
路上の雑音がなくＰＮ信号が正しく同期した状態であっ
ても、逆拡散出力のＳ／Ｎ比は３図−ａのピーク値と３
図−ｂの相関値の比にしかならない。The correlation characteristics when the SS signal spread by two kinds of PN signals of the same code and different codes with respect to the code to be despread and added at the same ratio to despread are shown in FIGS. The characteristics are obtained by averaging the characteristics of FIG. Therefore, even if there is no noise on the transmission path and the PN signal is correctly synchronized, the S / N ratio of the despread output is equal to the peak value of FIG.
It is only the ratio of the correlation values in FIG.
【００１０】また、同期の獲得と保持においても、符号
位相の判別の根拠となる相関特性が３図−ａの理想的な
状態から外れているので、誤った符号位相で同期した
り、位相に誤差や変動を生じたりする恐れがある。符号
の同期に位相誤差が生じると、位相誤差に比例して逆拡
散出力のＳ／Ｎは劣化し、符号の１ビット（以後、符号
のビットのことをチップと呼ぶ）以上の符号同期誤りが
あると、逆拡散が正しく行われなくなって、データの再
生は不可能になる。Also, in the acquisition and maintenance of the synchronization, since the correlation characteristic which is the basis for discriminating the code phase deviates from the ideal state shown in FIG. Errors or fluctuations may occur. When a phase error occurs in code synchronization, the S / N of the despread output deteriorates in proportion to the phase error, and a code synchronization error of one bit or more of the code (hereinafter, a code bit is referred to as a chip) occurs. If so, despreading will not be performed correctly and data reproduction will not be possible.
【００１１】[0011]
【課題を解決するための手段】本発明はこの目的を達成
するために、搬送波を４位相角変調する通信方式であっ
て、互いに直交する二つの搬送波が、同じ符号であって
符号位相が互いに異なる二つのＰＮ信号で周波数拡散さ
れることを特徴とするスペクトラム拡散通信方式であ
る。In order to achieve this object, the present invention provides a communication system for four-phase angle modulation of a carrier wave, wherein two mutually orthogonal carrier waves have the same code and code phases mutually. This is a spread spectrum communication system characterized in that the frequency is spread by two different PN signals.
【００１２】[0012]
【作用】互いに直交する二つの搬送波が、同じ符号であ
って符号位相が互いに異なる二つの疑似雑音信号で周波
数拡散されたＳＳ−ＱＰＳＫ信号の復調において、一方
の搬送波の復調に着目すると、送信側が使用したのと同
じ符号を、送信側と同期をとって掛け合わせると、目的
の搬送波が逆拡散された信号と、他方の搬送波が逆拡散
された信号の和が得られる。目的の搬送波は同期状態で
逆拡散されるので、逆拡散出力には３図−ａの自己相関
特性のピーク値に相当する電力が現れる。他方の搬送波
は一定の位相差がある状態で逆拡散されるので、逆拡散
出力には３図−ａの自己相関特性の平坦部の値に相当す
る電力が現れる。Ｍ系列のＰＮ信号を符号に選ぶと、同
じ符号であって位相が１ビット分以上異なる二つのＰＮ
信号の間の相関値が、二つのＰＮ信号間の相関値の中で
最低であることは数学的に保証されているので、本発明
の互いに直交する二つの搬送波が、同じ符号であって符
号位相が互いに異なる二つの疑似雑音信号で周波数拡散
されたＳＳ−ＱＰＳＫ信号は、二つの搬送波の間の相互
妨害が最小になる。In the demodulation of an SS-QPSK signal in which two carrier waves orthogonal to each other have the same code but are spread in frequency with two pseudo noise signals having different code phases, focusing on demodulation of one carrier wave, When the same code as used is multiplied in synchronization with the transmitting side, the sum of the signal obtained by despreading the target carrier and the signal obtained by despreading the other carrier is obtained. Since the target carrier is despread in a synchronized state, a power corresponding to the peak value of the autocorrelation characteristic shown in FIG. 3A appears in the despread output. Since the other carrier is despread with a certain phase difference, power corresponding to the value of the flat portion of the autocorrelation characteristic shown in FIG. 3A appears in the despread output. When an M-sequence PN signal is selected as a code, two PN signals having the same code but different in phase by one bit or more are used.
Since the correlation value between the signals is mathematically guaranteed to be the lowest of the correlation values between the two PN signals, the two orthogonal carriers of the present invention have the same sign and the same sign. An SS-QPSK signal spread in frequency with two pseudo noise signals having different phases has a minimum mutual interference between two carriers.
【００１３】また前述のように、送信機または受信機の
搬送波の９０度移相器の位相誤差や、受信機の搬送波再
生回路の位相誤差や、伝送路上や送受信回路内で生じる
波形ひずみなどによって、一方の搬送波の信号の一部が
他方の搬送波の信号に加わることがあるが、本発明の方
式によれば、二つの搬送の信号の加算は、同じ符号のＰ
Ｎ信号の位相をずらした加算になる。Ｍ系列のＰＮ信号
では、同じＰＮ信号を位相をずらして加算すると、同じ
符号であって加算された二つのＰＮ信号のいずれとも位
相が異なるＰＮ信号が得られるｃｙｃｌｅ−ａｎｄ−ａ
ｄｄ特性と呼ばれる性質があるので、他方の搬送波から
漏れ込んだ信号は、目的の搬送波の信号の一部と加算さ
れて、別の符号位相の信号に変換されることになる。前
述のように、同じ符号であって位相が１ビット分以上異
なるＰＮ信号は、最小の相関値をとるので、送信器また
は受信機の搬送波の９０度移相器の位相誤差や、受信機
の搬送波再生回路の位相誤差や、伝送路上や送受信回路
内で生じる波形ひずみなどによる搬送波間の相互妨害の
影響も最小となる。As described above, a phase error of a 90-degree phase shifter of a carrier wave of a transmitter or a receiver, a phase error of a carrier recovery circuit of a receiver, a waveform distortion generated on a transmission line or a transmission / reception circuit, or the like. , One part of the signal of one carrier may be added to the signal of the other carrier. According to the method of the present invention, the addition of the signals of the two carriers is performed by the P of the same sign.
The addition is performed by shifting the phase of the N signal. In the case of M-sequence PN signals, when the same PN signals are added with their phases shifted, a PN signal having the same sign but different in phase from any of the two added PN signals is obtained.
Since there is a property called a dd characteristic, a signal leaked from the other carrier is added to a part of a signal of a target carrier and converted into a signal of another code phase. As described above, a PN signal having the same code but a phase different by one bit or more takes the minimum correlation value, and therefore, a phase error of a 90-degree phase shifter of a carrier wave of a transmitter or a receiver or a PN signal of a receiver. The effects of mutual interference between carriers due to phase errors of the carrier recovery circuit and waveform distortions occurring on the transmission path and in the transmission / reception circuit are also minimized.
【００１４】このように本発明のＳＳ−ＱＰＳＫ方式に
よれば、互いに直交する二つの搬送波の間の相互妨害を
最小にし、良好な伝送品質を得ることができる。As described above, according to the SS-QPSK system of the present invention, it is possible to minimize mutual interference between two mutually orthogonal carriers and obtain good transmission quality.
【００１５】[0015]
【実施例】以下本発明の実施例について、図１を参照し
ながら説明する。図１は本発明のスペクトラム拡散通信
方式のブロック図である。発振器１は搬送波２１を発生
し、移相器２は搬送波２１から搬送波２１に対して９０
度位相のずれた搬送波２２をつくる。乗算器３はデータ
列２３を搬送波２１に掛け合わせてＢＰＳＫ信号２５を
つくり、乗算器４はデータ列２４を搬送波２２に掛け合
わせてＢＰＳＫ信号２６をつくる。発振器５はチップク
ロック２７を発生し、これに同期してＰＮ信号発生器６
はＭ系列のＰＮ信号２８を発生する。遅延回路７はＰＮ
信号２８を８チップ半遅延させてＰＮ信号２９をつく
る。乗算器８はＢＰＳＫ信号２５にＰＮ信号２８を掛け
合わせてＳＳ信号３０をつくり、乗算器９はＢＰＳＫ信
号２６にＰＮ信号２９を掛け合わせてＳＳ信号３１をつ
くる。加算器１０は二つのＳＳ信号３０と３１を２対１
の割合で足し合わせて送信信号３２をつくる。送信信号
３２は伝送路１１を通って受信信号３３となる。ＰＮ信
号発生器１２はＰＮ信号発生器６と同じ符号のＰＮ信号
３５を同期回路１３から得られるチップクロック３４に
同期して発生し、遅延回路１４はＰＮ信号３５を８チッ
プ半遅延させてＰＮ信号３６をつくる。同期回路１３は
ＰＮ信号３５の位相と受信信号３３との相関からＰＮ信
号２８とＰＮ信号３５の位相差を判別し、この位相差が
ゼロになるようにチップクロック３４の速度を制御す
る。乗算器１５は受信信号３３にＰＮ信号３５を掛け合
わせてＢＰＳＫ信号３７を得る。乗算器１６は受信信号
３３にＰＮ信号３６を掛け合わせてＢＰＳＫ信号３８を
得る。ＢＰＳＫ復調器１７はＢＰＳＫ信号３７を復調し
て復調データ列３９を得る。ＢＰＳＫ復調器１８はＢＰ
ＳＫ信号３７を復調して復調データ列４０を得る。An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram of a spread spectrum communication system according to the present invention. The oscillator 1 generates a carrier wave 21, and the phase shifter 2 generates a carrier wave 21 from the carrier wave 21 with respect to the carrier wave 21.
A carrier wave 22 having a phase shift is produced. The multiplier 3 multiplies the data sequence 23 by the carrier 21 to generate a BPSK signal 25, and the multiplier 4 multiplies the data sequence 24 by the carrier 22 to generate a BPSK signal 26. The oscillator 5 generates a chip clock 27, and in synchronization with the chip clock 27, a PN signal generator 6
Generates an M-sequence PN signal 28. The delay circuit 7 is PN
The PN signal 29 is created by delaying the signal 28 by eight chips and a half. The multiplier 8 multiplies the BPSK signal 25 by the PN signal 28 to generate an SS signal 30, and the multiplier 9 multiplies the BPSK signal 26 by the PN signal 29 to generate the SS signal 31. The adder 10 converts the two SS signals 30 and 31 two-to-one.
The transmission signal 32 is created by adding the signals at the ratio of The transmission signal 32 passes through the transmission path 11 and becomes a reception signal 33. The PN signal generator 12 generates a PN signal 35 having the same sign as that of the PN signal generator 6 in synchronization with a chip clock 34 obtained from the synchronizing circuit 13. Generate signal 36. The synchronization circuit 13 determines the phase difference between the PN signal 28 and the PN signal 35 from the correlation between the phase of the PN signal 35 and the received signal 33, and controls the speed of the chip clock 34 so that the phase difference becomes zero. Multiplier 15 obtains BPSK signal 37 by multiplying received signal 33 by PN signal 35. Multiplier 16 multiplies received signal 33 by PN signal 36 to obtain BPSK signal 38. The BPSK demodulator 17 demodulates the BPSK signal 37 to obtain a demodulated data sequence 39. BPSK demodulator 18 is BP
The SK signal 37 is demodulated to obtain a demodulated data sequence 40.
【００１６】このような構成の通信システムにおける遅
延回路７及び１４の遅延量は、マルチパスによる障害が
想定される場合には、遅れて入る反射波の予想される最
大遅延時間よりも大きな遅延量に設定すべきである。な
ぜなら、ＰＮ信号の位相差に相当する時間差をおいて反
射波が届くと、反射波の中のＰＮ信号２８で拡散された
信号成分と、直接波の中のＰＮ信号２９で拡散された信
号成分の、拡散符号の位相が一致するために、逆拡散に
よっては分離できない妨害を生ずるからである。In the communication system having such a configuration, the delay amount of the delay circuits 7 and 14 is larger than the expected maximum delay time of the reflected wave that is delayed when a failure due to multipath is assumed. Should be set to Because, when the reflected wave arrives at a time difference corresponding to the phase difference of the PN signal, the signal component diffused by the PN signal 28 in the reflected wave and the signal component diffused by the PN signal 29 in the direct wave This is because, because the phases of the spreading codes match, interference that cannot be separated by despreading occurs.
【００１７】また、遅延量をチップクロックの整数倍に
せず、半チップ分余計にずらす理由はオフセットＱＰＳ
Ｋの考えかたと同じで、キャリア位相の不連続を小さく
することによって、回路の非線形性の為に生じる位相誤
差を小さくするためである。The reason why the delay amount is not shifted to an integral multiple of the chip clock but is shifted by an extra half chip is the offset QPS.
This is because, as in the case of K, by reducing the discontinuity of the carrier phase, the phase error generated due to the non-linearity of the circuit is reduced.
【００１８】前述の加算器１０において、二つのＳＳ信
号３０と３１を２対１の割合で足し合わせるのは、同期
回路１３において位相の判別を容易にする為である。Ｐ
Ｎ信号３５と受信信号３３との相関をとると、相関値が
二つの位相でピークを持つ。しかし二つのＳＳ信号には
電力の大きさに差を与えているので、相関値のピークの
大きさを比較すれば容易に両者を判別できる。The reason why the two SS signals 30 and 31 are added at a ratio of 2 to 1 in the adder 10 is to make it easy for the synchronization circuit 13 to determine the phase. P
When the correlation between the N signal 35 and the received signal 33 is obtained, the correlation value has peaks at two phases. However, since a difference is provided in the magnitude of the power between the two SS signals, the two can be easily distinguished by comparing the magnitude of the peak of the correlation value.
【００１９】同期回路の働きによりＰＮ信号３５がＰＮ
信号２８に同期すると、これらに対して同じ遅延量分だ
け位相が遅れているＰＮ信号３６とＰＮ信号２９も必然
的に同期する。乗算器１５で同期のとれたＰＮ信号２８
を受信信号に掛け合わせるとＳＳ信号３０の成分はＰＮ
信号２８による周波数拡散が打ち消されて狭帯域のＢＰ
ＳＫ信号３７になる。ＳＳ信号３１の成分も逆拡散され
るが、同じ符号で位相が大きくことなるために相関が小
さいので、ＢＰＳＫ復調器１７の帯域内に現れる電力は
小さく、無視できる程度である。乗算器１６においても
同様の原理で、ＳＳ信号３１の成分が逆拡散されてＢＰ
ＳＫ信号３８になる。By the operation of the synchronization circuit, the PN signal 35 becomes PN.
When synchronized with the signal 28, the PN signal 36 and the PN signal 29 whose phases are delayed by the same delay amount with respect to these signals are also necessarily synchronized. PN signal 28 synchronized by multiplier 15
Is multiplied by the received signal, the component of the SS signal 30 becomes PN
Narrow band BP by canceling the frequency spread by signal 28
It becomes the SK signal 37. The component of the SS signal 31 is also despread, but since the phase is large with the same code and the correlation is small, the power appearing in the band of the BPSK demodulator 17 is small and negligible. In the multiplier 16, the components of the SS signal 31 are despread and the BP
It becomes the SK signal 38.
【００２０】ＳＳ−ＱＰＳＫ方式では逆拡散によって、
互いに直交する二つの搬送波を分離できるので、最終的
なデータの復調はＢＰＳＫの復調器で行える。特に、本
発明の通信方式では互いに直交する二つの搬送波を、同
じ符号であって符号位相が互いに異なる二つのＰＮ信号
で周波数拡散することにより、二つの搬送波が相互に与
える妨害を最小にし、Ｓ／Ｎが良好な状態でデータの復
調ができる。In the SS-QPSK system, by despreading,
Since two orthogonal carriers can be separated from each other, the final data can be demodulated by a BPSK demodulator. In particular, in the communication system of the present invention, two carrier waves orthogonal to each other are frequency-spread with two PN signals having the same code but different code phases, thereby minimizing interference caused by the two carrier waves. Data demodulation can be performed with good / N.
【００２１】[0021]
【発明の効果】本発明の方式によれば、互いに直交する
二つの搬送波を、同じ符号であって符号位相が互いに異
なる二つのＰＮ信号で周波数拡散することにより、二つ
の搬送波が相互に与える妨害を最小にし、良好な伝送品
質を得ることができる。According to the method of the present invention, two carrier waves which are orthogonal to each other are frequency-spread by two PN signals having the same code but different code phases, so that the two carrier waves cause mutual interference. , And good transmission quality can be obtained.
【図１】本発明のスペクトラム拡散通信方式の実施例を
示すブロック図FIG. 1 is a block diagram showing an embodiment of a spread spectrum communication system according to the present invention.
【図２】従来例のスペクトラム拡散通信方式の一例を示
すブロック図FIG. 2 is a block diagram showing an example of a conventional spread spectrum communication system.
【図３】ＰＮ信号の位相相関特性を示す波形図FIG. 3 is a waveform chart showing a phase correlation characteristic of a PN signal.
【図４】ＱＰＳＫ信号の位相と信号の関係を示す説明図FIG. 4 is an explanatory diagram showing a relationship between a phase of a QPSK signal and a signal;
１ 発振器 ２ 移相器 ３ 乗算器 ４ 乗算器 ５ 発振器 ６ ＰＮ信号発生器 ７ 遅延回路 ８ 乗算器 ９ 乗算器 １０ 加算器 １１ 伝送路 １２ ＰＮ信号発生器 １３ 同期回路 １４ 遅延回路 １５ 乗算器 １６ 乗算器 １７ ＢＰＳＫ復調器 １８ ＢＰＳＫ復調器 DESCRIPTION OF SYMBOLS 1 Oscillator 2 Phase shifter 3 Multiplier 4 Multiplier 5 Oscillator 6 PN signal generator 7 Delay circuit 8 Multiplier 9 Multiplier 10 Adder 11 Transmission line 12 PN signal generator 13 Synchronization circuit 14 Delay circuit 15 Multiplier 16 Multiplication 17 BPSK demodulator 18 BPSK demodulator
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H04B 1/69 - 1/713 H04J 13/00 - 13/06 H04L 27/00 - 27/38──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl.7 , DB name) H04B 1/69-1/713 H04J 13/00-13/06 H04L 27/00-27/38
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13084493AJP3152013B2 (en) | 1993-06-01 | 1993-06-01 | Spread spectrum communication system |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13084493AJP3152013B2 (en) | 1993-06-01 | 1993-06-01 | Spread spectrum communication system |
| Publication Number | Publication Date |
|---|---|
| JPH06343068A JPH06343068A (en) | 1994-12-13 |
| JP3152013B2true JP3152013B2 (en) | 2001-04-03 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13084493AExpired - Fee RelatedJP3152013B2 (en) | 1993-06-01 | 1993-06-01 | Spread spectrum communication system |
| Country | Link |
|---|---|
| JP (1) | JP3152013B2 (en) |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |