JP2019083475A - OAM multiplex communication system and OAM multiplex communication method - Google Patents

OAM multiplex communication system and OAM multiplex communication method Download PDF

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JP2019083475A
JP2019083475A JP2017211106A JP2017211106A JP2019083475A JP 2019083475 A JP2019083475 A JP 2019083475A JP 2017211106 A JP2017211106 A JP 2017211106A JP 2017211106 A JP2017211106 A JP 2017211106A JP 2019083475 A JP2019083475 A JP 2019083475A
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JP6962135B2 (en
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斗煥 李
Doohwan Lee
斗煥 李
裕文 笹木
Hirofumi Sasaki
裕文 笹木
浩之 福本
Hiroyuki Fukumoto
浩之 福本
宏礼 芝
Hironori Shiba
宏礼 芝
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Nippon Telegraph and Telephone Corp
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Abstract

To reduce an amount of calculation necessary for removal of OAM inter-mode interference as a multiplex number increases when OAM inter-mode interference occurs in OAM communication and OAM-MIMO communication and, in addition, reduce a channel estimation load necessary for removal of OAM inter-mode interference.SOLUTION: In an OAM multiplex communication system, a UCA of a transmission device generates and transmits signals of a plurality of OAM modes, a UCA of a reception device receives and separates the signals of the plurality of OAM modes, the signals the number of which is the number of the OAM modes are spatial multiplex transmitted. The reception device includes interference removal means that determines "between OAM modes" that causes interference larger than a predetermined threshold value 1 using channel information between the OAM modes and performs interference removal processing on "the between OAM modes."SELECTED DRAWING: Figure 2

Description

本発明は、電磁波の軌道角運動量（Orbital Angular Momentum：ＯＡＭ）を用いて無線信号を空間多重伝送するＯＡＭ多重通信システムおよびＯＡＭ多重通信方法に関する。   The present invention relates to an OAM multiplex communication system and an OAM multiplex communication method in which wireless signals are spatially multiplexed and transmitted using Orbital Angular Momentum (OAM) of electromagnetic waves.

近年、伝送容量向上のため、ＯＡＭを用いた無線信号の空間多重伝送技術が報告されている（非特許文献１）。ＯＡＭをもつ電磁波は、伝搬軸を中心に伝搬方向にそって等位相面が螺旋状に分布する。異なるＯＡＭモードをもち、同一方向に伝搬する電磁波は、回転軸方向において空間位相分布が直交するため、異なる信号系列で変調された各ＯＡＭモー
ドの信号を受信局において分離することにより、信号を多重伝送することが可能である。 In recent years, a space multiplex transmission technology of a radio signal using OAM has been reported to improve transmission capacity (Non-Patent Document 1). In the electromagnetic wave having OAM, the equiphase surface is spirally distributed along the propagation direction around the propagation axis. Since electromagnetic waves having different OAM modes and propagating in the same direction have orthogonal spatial phase distributions in the rotational axis direction, the signals are multiplexed by separating the signals of each OAM mode modulated by different signal sequences at the receiving station. It is possible to transmit.

このＯＡＭ多重技術を用いた無線通信システムでは、複数のアンテナ素子を等間隔に円形配置した等間隔円形アレーアンテナ（以下、ＵＣＡ（Uniform Circular Array）と称する。）を用い、複数のＯＡＭモードを生成・合成して送信することにより、異なる信号系列の空間多重伝送が行われる（非特許文献２）。   In a wireless communication system using this OAM multiplexing technology, a plurality of OAM modes are generated using equally spaced circular array antennas (hereinafter referred to as UCA (Uniform Circular Array)) in which a plurality of antenna elements are circularly arranged at equal intervals. -By multiplexing and transmitting, spatial multiplex transmission of different signal sequences is performed (Non-Patent Document 2).

図５は、ＯＡＭモードの信号を生成するためのＵＣＡの位相設定例を示す。
図５において、送信側におけるＯＡＭモード０，１，２，３，…の信号は、ＵＣＡの各アンテナ素子（●で示す）に設定する位相差により生成される。すなわち、ＯＡＭモードｎの信号は、ＵＣＡの位相がｎ回転（ｎ×360 度）になるように各アンテナ素子の位相を設定して生成する。例えば、ＵＣＡが８個のアンテナ素子で構成される場合で、ＯＡＭモード２の信号を生成する場合は、図５(3) に示すように、位相が２回転するように、各アンテナ素子に反時計回りに90度の位相差を設定する。なお、ＯＡＭモードｎの信号に対して位相の回転方向を逆にした信号をＯＡＭモード−ｎとする。例えば、正のＯＡＭモードの信号の位相の回転方向を反時計回りとし、負のＯＡＭモードの信号の位相の回転方向を時計回りとする。 FIG. 5 shows an example of phase setting of the UCA for generating an OAM mode signal.
In FIG. 5, the signals in the OAM modes 0, 1, 2, 3,... On the transmission side are generated by the phase difference set to each antenna element (indicated by .circle-solid.) Of the UCA. That is, the signal of the OAM mode n is generated by setting the phase of each antenna element such that the phase of UCA is n rotations (n × 360 degrees). For example, in the case where the UCA is configured of eight antenna elements, when generating a signal of OAM mode 2, as shown in FIG. 5 (3), each antenna element is opposed so that the phase is rotated twice. Set a phase difference of 90 degrees clockwise. A signal obtained by reversing the rotation direction of the phase with respect to the signal of the OAM mode n is referred to as an OAM mode-n. For example, the rotation direction of the phase of the signal of the positive OAM mode is counterclockwise, and the rotation direction of the phase of the signal of the negative OAM mode is clockwise.

異なる信号系列を異なるＯＡＭモードの信号として生成し、生成した信号を同時に送信することで、空間多重による無線通信ができる。送信側では、各ＯＡＭモードで伝送する信号をあらかじめ生成・合成し、単一のＵＣＡで各ＯＡＭモードの合成信号を送信してもよいし、複数のＵＣＡを用いて、ＯＡＭモード毎に異なるＵＣＡで各ＯＡＭモードの信号を送信してもよい。   Wireless communication by space multiplexing can be performed by generating different signal sequences as signals of different OAM modes and simultaneously transmitting the generated signals. On the transmission side, signals to be transmitted in each OAM mode may be generated and synthesized in advance, and a single UCA may be used to transmit a combined signal of each OAM mode, or a plurality of UCAs may be used to generate different UCAs for each OAM mode. The signal of each OAM mode may be transmitted.

図６は、ＯＡＭ多重信号の位相分布と信号強度分布の例を示す。
図６(1),(2) において、送信側から伝搬方向に直交する端面（以下、伝搬直交平面と称する。）で見た、ＯＡＭモード１とＯＡＭモード２の信号の位相分布を矢印で表す。矢印の始めは０度であり、位相が線形に変化して矢印の終わりは 360度である。すなわち、ＯＡＭモードｎの信号は、伝搬直交平面において、位相がｎ回転（ｎ×360 度）しながら伝搬する。 FIG. 6 shows an example of the phase distribution and signal strength distribution of the OAM multiplexed signal.
In FIG. 6 (1) and (2), the phase distributions of the signals in OAM mode 1 and OAM mode 2 are indicated by arrows, as viewed from the end face orthogonal to the propagation direction from the transmission side (hereinafter referred to as propagation orthogonal plane). . The beginning of the arrow is 0 degrees, the phase changes linearly, and the end of the arrow is 360 degrees. That is, the signal of the OAM mode n propagates with n phases (n × 360 degrees) of phase rotation in the propagation orthogonal plane.

各ＯＡＭモードの信号は、ＯＡＭモード毎に信号強度分布と信号強度が最大になる位置が異なる。具体的には、ＯＡＭモードが高次になるほど、信号強度が最大になる位置が伝搬軸から遠くなる（非特許文献２）。ここで、ＯＡＭモードの値が大きい方を高次モードと称する。例えば、ＯＡＭモード３の信号は、ＯＡＭモード０、ＯＡＭモード１、ＯＡＭモード２の信号より、高次モードである。   The signal in each OAM mode has different signal strength distribution and different position where the signal strength is maximum for each OAM mode. Specifically, as the OAM mode becomes higher, the position at which the signal strength is maximized is farther from the propagation axis (Non-Patent Document 2). Here, the larger value of the OAM mode is referred to as a higher order mode. For example, the signal of OAM mode 3 is a higher order mode than the signals of OAM mode 0, OAM mode 1 and OAM mode 2.

図６(3) は、ＯＡＭモードごとに信号強度が最大になる位置を円環で示すが、ＯＡＭモードが高次になるほど信号強度が最大になる位置が中心軸から遠くなり、かつ伝搬距離に応じてＯＡＭモード多重信号のビーム径が広がり、ＯＡＭモードごとに信号強度が最大になる位置を示す円環が大きくなる。   In FIG. 6 (3), the position where the signal strength is maximized for each OAM mode is indicated by a ring, but the position where the signal strength is maximized as the OAM mode becomes higher becomes farther from the central axis and the propagation distance Accordingly, the beam diameter of the OAM mode multiplexed signal spreads, and the ring indicating the position where the signal strength becomes maximum becomes large for each OAM mode.

図７は、ＯＡＭ多重信号を分離するためのＵＣＡの位相設定例を示す。
図７において、受信側では、ＵＣＡの各アンテナ素子の位相を、送信側のアンテナ素子の位相と逆方向になるように設定し、各ＯＡＭモードの信号を分離する。すなわち、各アンテナ素子の位相は、図５の場合と逆方向に回転するように設定し、例えばＯＡＭモード２の信号を分離する場合は、位相が２回転するように、各アンテナ素子に時計回りに90度の位相差を設定する。 FIG. 7 shows an example of UCA phase setting for separating an OAM multiplexed signal.
In FIG. 7, on the reception side, the phase of each antenna element of UCA is set to be in the opposite direction to the phase of the antenna element on the transmission side, and the signal of each OAM mode is separated. That is, the phase of each antenna element is set to rotate in the opposite direction to that in FIG. 5. For example, in the case of separating an OAM mode 2 signal, each antenna element is rotated clockwise so that the phase rotates twice. Set the phase difference to 90 degrees.

ＯＡＭ通信は、ＯＡＭモードの次数を高くすることにより、理論的には多重数を無限に増やすことができる。しかし、ＯＡＭモードが高次になるほど受信電力が低下するため（非特許文献３）、現実的に使えるＯＡＭモードの数には制限がある。例えば、ＯＡＭモード±２までは所望の受信電力を満たすが、ＯＡＭモード±３より高いＯＡＭモードは所望の受信電力を満たさない場合には、使えるＯＡＭモードが２，１，０，−１，−２の５つに制限されることになる。   The OAM communication can theoretically increase the number of multiplexes infinitely by raising the order of the OAM mode. However, since the received power decreases as the OAM mode becomes higher (Non-Patent Document 3), the number of OAM modes that can be practically used is limited. For example, if the desired received power is satisfied up to the OAM mode ± 2, but the OAM mode higher than the OAM mode ± 3 does not satisfy the desired received power, the usable OAM modes are 2, 1, 0, −1, − It will be limited to 5 of 2.

一方、図８に示すように、同心円状に複数のＵＣＡを配置したＭ（Multi)−ＵＣＡを用い、ＵＣＡ毎に所要の受信電力を満たすＯＡＭモードを使うことで、多重数を増やすことができる。例えば互いに半径が異なる４個のＵＣＡ１，ＵＣＡ２，ＵＣＡ３，ＵＣＡ４を用い、各ＵＣＡがＯＡＭモード２，１，０，−１，−２を用いてそれぞれ異なる信号列を５多重伝送すると、４個のＵＣＡの合計で20多重伝送が可能となる。この場合、ＯＡＭモード間の独立な特性により、各ＵＣＡの異なるＯＡＭモード間では干渉が生じないが、各ＵＣＡの同一のＯＡＭモード間では受信側にて干渉が生じるため、等化処理等により同一ＯＡＭモード間の信号を分離する必要がある。   On the other hand, as shown in FIG. 8, the number of multiplexing can be increased by using an M (Multi) -UCA in which a plurality of UCAs are arranged concentrically and using an OAM mode satisfying the required reception power for each UCA. . For example, if four UCA1, UCA2, UCA3 and UCA4 with different radii are used and each UCA transmits five different signal sequences using OAM mode 2, 1, 0, -1, -2, respectively, A total of 20 UCA transmissions are possible. In this case, although interference does not occur between different OAM modes of each UCA due to the independent characteristics between OAM modes, interference occurs at the receiving side between the same OAM modes of each UCA. It is necessary to separate the signals between OAM modes.

すなわち、Ｍ−ＵＣＡを構成するｍ個のＵＣＡは、それぞれｎ個のＯＡＭモードの信号を生成し、それらを同時に送信することにより、ｍ×ｎの時系列データ（ストリーム）を空間多重して伝送することができる。上記の例では、送信側から４個のＵＣＡと５個のＯＡＭモードを用いて20ストリームの多重伝送を行った場合に、受信側では４個のＵＣＡで受信するＯＡＭモード２，１，０，−１，−２ごとに４個のストリームの分離処理を行うことで、20ストリームの信号を分離することができる。これにより、高次ＯＡＭモードを使わず、複数のＵＣＡで低次ＯＡＭモードを複数送信し、同じＯＡＭモード間のみで信号分離処理を行うことで、多重数を増やし、伝送容量を向上することができる。   In other words, the m UCAs that make up the M-UCA generate n OAM mode signals and transmit them simultaneously, thereby spatially multiplexing and transmitting m × n time series data (stream) can do. In the above example, when multiplex transmission of 20 streams is performed from the transmitting side using 4 UCAs and 5 OAM modes, the receiving side receives OAM modes 2, 1, 0, By performing separation processing of four streams for each of -1 and -2, signals of 20 streams can be separated. As a result, the transmission capacity can be improved by increasing the number of multiplexes by transmitting a plurality of low-order OAM modes with a plurality of UCAs without using the high-order OAM mode and performing signal separation processing only between the same OAM modes. it can.

以下、単一のＵＣＡを用いた伝送方法を「ＯＡＭ通信」と称し、Ｍ−ＵＣＡを用いた伝送方法を「ＯＡＭ−ＭＩＭＯ通信」と称する。   Hereinafter, a transmission method using a single UCA is referred to as “OAM communication”, and a transmission method using M-UCA is referred to as “OAM-MIMO communication”.

J. Wang et al., “Terabit free-space data transmission employing orbital angular momentum multiplexing, ”Nature Photonics, Vol.6, pp.488-496, July 2012.J. Wang et al., “Terabit free-space data transmission employing angular angular moment multiplexing,” Nature Photonics, Vol. 6, pp. 488-496, July 2012. Y. Yan et al.,“High-capacity millimeter-wavecommunications with orbital angular momentum multiplexing,”Nature Commun., vol.5, p.4876, Sep. 2014.Y. Yan et al., "High-capacity millimeter-wave communication with orbital angular momentum multiplexing," Nature Commun., Vol. 5, p. 4876, Sep. 2014. A. Cagliero et al., “A New Approach to the Link Budget Concept for an OAM Communication Link,”IEEE Antennas and Wireless Propagation Letters, vol.15, pp.568-571. 2016A. Cagliero et al., “A. New Approach to the Link Budget Concept for OAM Communication Link,” IEEE Antennas and Wireless Propagation Letters, vol. 15, pp. 568-571. 2016

（ＯＡＭ通信における課題）
ＯＡＭ通信では、各ＯＡＭモードは独立のため、ＯＡＭモード間干渉除去は理論的には不要である。しかし、送受信ＵＣＡの軸ズレやＲＦ回路の不完全性等により、ＯＡＭモード間で干渉が生じる場合には、このＯＡＭモード間干渉を除去する必要が生じる。この干渉除去法として、各ＯＡＭモードの送信ストリームを従来のＭＩＭＯ通信の各ストリームとしてみなし、従来のＭＩＭＯ等化技術等で干渉除去を行う手法が考えられる。 (Problems in OAM communication)
In OAM communication, since each OAM mode is independent, interference cancellation between OAM modes is theoretically unnecessary. However, when interference occurs between the OAM modes due to the misalignment of the transmission / reception UCA, the imperfection of the RF circuit, or the like, it is necessary to remove the interference between the OAM modes. As this interference removal method, a method may be considered in which the transmission stream of each OAM mode is regarded as each stream of the conventional MIMO communication, and the interference removal is performed by the conventional MIMO equalization technology or the like.

しかしながら、この干渉除去法では、多重数が増加すると演算量が多重数の３乗に比例し増加する課題がある。また、この干渉除去法の適用のためには、各ＯＡＭモードから他のすべてのＯＡＭモードへの干渉の度合い、すなわちチャネル情報を取得する必要が生じる。そのため、多重数の増加に伴ってチャネル推定の負荷が多重数の２乗に比例して生じる課題がある。例えば、５個のＯＡＭモードを用いて多重通信を行う場合、25個のチャネル情報の取得が必要となる。   However, in this interference removal method, there is a problem that the amount of operation increases in proportion to the cube of the number of multiplexing as the number of multiplexing increases. Also, in order to apply this interference cancellation method, it is necessary to obtain the degree of interference from each OAM mode to all other OAM modes, that is, to acquire channel information. Therefore, there is a problem that the load of channel estimation occurs in proportion to the square of the number of multiplexing as the number of multiplexing increases. For example, when multiplex communication is performed using five OAM modes, it is necessary to acquire 25 channel information.

この干渉除去に必要な演算量の増加に対して受信装置の演算能力が一定の場合、送受信可能多重数が制限されて、伝送容量が低下する課題がある。また、一般的に、チャネル情報の取得は、送信装置が既知信号を送り、受信装置がその既知信号を用いてチャネル推定を行う。そのため、既知情報の量が増えると、送受信するデータ量が減ることになって伝送容量が低下することになる。また、チャネル推定に必要な演算量も増加する課題がある。また、干渉の度合いを周期的に把握し干渉除去処理を適応的に行う必要がある。   When the calculation capability of the receiving apparatus is constant with respect to the increase of the calculation amount required for the interference removal, there is a problem that the number of transmittable / receivable multiplexes is limited and the transmission capacity is reduced. Also, in general, in obtaining channel information, a transmitter sends a known signal and a receiver performs channel estimation using the known signal. Therefore, when the amount of known information increases, the amount of data to be transmitted and received decreases, and the transmission capacity decreases. Also, there is a problem that the amount of computation required for channel estimation also increases. In addition, it is necessary to periodically grasp the degree of interference and to perform the interference removal processing adaptively.

（ＯＡＭ−ＭＩＭＯ通信における課題）
送受信装置がそれぞれ、Ｍ−ＵＣＡを用いて多重伝送を行うＯＡＭ−ＭＩＭＯ通信では、理論的には、同一のＯＡＭモード間の信号分離処理のみで、すべてのストリームの分離が可能である。ここで、同一のＯＡＭモード間の信号分離処理は、同一のＯＡＭモード間のチャネル情報を用いて、ＺＦ(zero forcing)やＭＭＳＥ(minimum mean square error) 手法など一般的に使われる等化手法と、ＭＬＤ（Maximum likelihood decoding)、ＭＤＤ（Minimum distance decoding)、ＶＤ（Viterbi decoder ）等の無線通信システムにおいて、一般的に用いられる等化・分離手法が想定される。 (Problems in OAM-MIMO communication)
In OAM-MIMO communication in which each of the transmitting and receiving apparatuses performs multiplex transmission using M-UCA, theoretically, all streams can be separated only by signal separation processing between the same OAM modes. Here, signal separation processing between the same OAM modes is generally performed using equalization techniques such as ZF (zero forcing) and MMSE (minimum mean square error) methods using channel information between the same OAM modes. Equalization / separation techniques generally used in wireless communication systems such as MLD (Maximum likelihood detection), MDD (Minimum distance decoding), VD (Viterbi decoder) and the like are assumed.

しかしながら、軸ズレやＲＦ回路等によりＯＡＭモード間干渉が生じると、同一ＯＡＭモード間の信号分離以外にも、ＯＡＭ通信における課題と同様に、異なるＯＡＭモード間の干渉除去処理を行う必要が生じる。この干渉除去法として、Ｍ−ＵＣＡの各ＯＡＭモードの送信ストリームを従来のＭＩＭＯ通信の各ストリームとしてみなし、従来のＭＩＭＯ等化技術等で干渉除去を行う手法が考えられる。しかしながら、この干渉除去法では、ＯＡＭ通信における課題と同様に、多重数が増加すると演算量が多重数の３乗に比例し増加し、チャネル推定の負荷が多重数の２乗に比例して増加する課題がある。これらにより、伝送容量が低下する課題がある。また、干渉の度合いを周期的に把握し干渉除去処理を適応的に行う必要がある。   However, when interference between OAM modes occurs due to an axis shift, an RF circuit or the like, in addition to signal separation between the same OAM modes, it becomes necessary to perform interference removal processing between different OAM modes as in the case of OAM communication. As this interference removal method, a method may be considered in which the transmission stream of each OAM mode of M-UCA is regarded as each stream of the conventional MIMO communication, and the interference removal is performed by the conventional MIMO equalization technique or the like. However, in this interference cancellation method, as in the case of OAM communication, when the multiplexing number increases, the amount of operation increases in proportion to the cube of the multiplexing number, and the load of channel estimation increases in proportion to the square of the multiplexing number Have a challenge to As a result, there is a problem that transmission capacity is reduced. In addition, it is necessary to periodically grasp the degree of interference and to perform the interference removal processing adaptively.

このように、ＯＡＭ通信およびＯＡＭ−ＭＩＭＯ通信において、ＯＡＭモード間干渉が生じる場合、多重数の増加に伴いＯＡＭモード間干渉除去に必要な演算量が増加する。また、ＯＡＭモード間干渉除去のため必要なチャネル推定負荷も増加する。   Thus, in the case where OAM mode interference occurs in OAM communication and OAM-MIMO communication, the amount of calculation required for OAM mode interference cancellation increases with the increase in the number of multiplexes. Also, the channel estimation load required for OAM mode interference cancellation is increased.

本発明は、ＯＡＭ通信およびＯＡＭ−ＭＩＭＯ通信において、ＯＡＭモード間干渉が生じる場合に、多重数の増加に伴いＯＡＭモード間干渉除去に必要な演算量を削減し、さらにＯＡＭモード間干渉除去に必要なチャネル推定負荷も軽減することができるＯＡＭ多重通信システムおよびＯＡＭ多重通信方法を提供することを目的とする。   The present invention reduces the amount of calculation required for inter-OAM mode interference cancellation as the number of multiplexing increases when inter-OAM mode interference occurs in OAM communication and OAM-MIMO communication, and is further required for inter-OAM mode interference cancellation It is an object of the present invention to provide an OAM multiplex communication system and an OAM multiplex communication method capable of reducing various channel estimation loads.

第１の発明は、送信装置のＵＣＡで複数のＯＡＭモードの信号を生成して送信し、受信装置のＵＣＡで複数のＯＡＭモードの信号を受信して分離し、ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信システムにおいて、受信装置は、ＯＡＭモード間のチャネル情報を用いて、所定の閾値１より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う干渉除去手段を備える。   In the first invention, the UCA of the transmission apparatus generates and transmits a plurality of OAM mode signals, and the UCA of the reception apparatus receives and separates the plurality of OAM mode signals, and spatially multiplexes the number of OAM mode signals. In an OAM multiplex communication system for transmission, a receiver determines channel interference between OAM modes using channel information between OAM modes, and performs interference cancellation processing between the OAM modes. Means are provided.

第１の発明のＯＡＭ多重通信システムにおいて、干渉除去手段は、各ＯＡＭモード間の干渉信号電力を計算し、その最大干渉信号電力が所定の閾値１以下の場合は、ＯＡＭモード間の干渉除去処理を行わずに、各ＯＡＭモードの受信信号の復調処理を行う処理手段１と、各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が閾値１より大きいＯＡＭモード組数が所定の閾値２以下の場合は、干渉信号電力が閾値１以下のＯＡＭモード間を除くＯＡＭモード間のみの干渉除去処理を行い、各ＯＡＭモードの受信信号の復調処理を行う処理手段２と、各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が閾値１より大きいＯＡＭモード組数が所定の閾値２より大きい場合は、各ＯＡＭモードのすべての受信信号とすべてのＯＡＭモード間のチャネル情報を用いて干渉除去処理を行い、各ＯＡＭモードの受信信号の復調処理を行う処理手段３とを備える。   In the OAM multiplex communication system according to the first invention, the interference removing means calculates interference signal power between each OAM mode, and when the maximum interference signal power is less than or equal to a predetermined threshold 1, the interference removal process between OAM modes is performed. Calculating the interference signal power between each OAM mode and the processing means 1 for performing demodulation processing of the received signal of each OAM mode, and determining the predetermined threshold value of the number of OAM mode groups whose interference signal power is larger than the threshold 1 In the case of 2 or less, the interference removal processing is performed only between the OAM modes except between the OAM modes where the interference signal power is less than or equal to the threshold 1, and the processing means 2 performs demodulation processing of the received signal in each OAM mode Interference signal power is calculated, and if the number of OAM mode sets whose interference signal power is greater than threshold 1 is greater than predetermined threshold 2, then all received signals and all O's of each OAM mode are Perform interference removal processing using the channel information between M-mode, and a processing unit 3 for performing demodulation processing of the received signals of the respective OAM mode.

第１の発明のＯＡＭ多重通信システムにおいて、干渉除去手段は、所定の時間間隔ごとにすべてのＯＡＭモード間のチャネル情報を取得し、その区間は、所定の閾値１より大きい干渉を及ぼすＯＡＭモード間のみのチャネル情報を取得する構成である。   In the OAM multiplex communication system according to the first invention, the interference removing means acquires channel information between all the OAM modes every predetermined time interval, and the section is between the OAM modes which exert interference larger than a predetermined threshold 1 Channel information is acquired.

第２の発明は、同心円状に配置した複数のＵＣＡからなるＭ−ＵＣＡを送信装置と受信装置に備え、送信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を生成して送信し、受信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を受信して分離し、ＵＣＡ数×ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信システムにおいて、受信装置は、送信装置は各ＵＣＡの各ＯＡＭモード間のチャネル情報を用いて、各ＵＣＡで受信する同一ＯＡＭモード間の信号分離を行うとともに、所定の閾値３より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う干渉除去手段を備える。   According to a second aspect of the present invention, an M-UCA comprising a plurality of UCAs arranged concentrically is provided in a transmitter and a receiver, and each UCA of the transmitter generates and transmits a plurality of OAM mode signals. In an OAM multiplex communication system in which signals of a plurality of OAM modes are respectively received and separated by each of the UCAs and the signals of the number of UCAs × the number of OAM modes are spatially multiplexed and transmitted, the receiving apparatus is a transmitting apparatus having each OAM mode of each UCA. While performing signal separation between the same OAM mode received by each UCA using channel information between them, determine between OAM modes that cause interference larger than a predetermined threshold value 3 and perform interference removal processing between the OAM modes An interference removing means is provided.

第２の発明のＯＡＭ多重通信システムにおいて、干渉除去手段は、複数のＵＣＡの各ＯＡＭモード間の干渉信号電力を計算し、その最大干渉信号電力が所定の閾値３以下の場合は、ＯＡＭモード間の干渉除去処理を行わずに、各ＵＣＡにおける同一ＯＡＭモード間の等化処理による信号分離処理を行い、分離後の各ＯＡＭモードの受信信号の復調処理を行う処理手段１と、複数のＵＣＡの各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が閾値３より大きいＯＡＭモード組数が所定の閾値４以下の場合は、干渉信号電力が閾値３以下のＯＡＭモード間を除くＯＡＭモード間のみの干渉除去処理を行い、各ＵＣＡの各ＯＡＭモードの受信信号の復調処理を行う処理手段２と、複数のＵＣＡの各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が閾値３より大きいＯＡＭモード組数が所定の閾値４より大きい場合は、各ＵＣＡの各ＯＡＭモードのすべての受信信号と、すべてＵＣＡのＯＡＭモード間のチャネル情報を用いて干渉除去処理を行い、各ＵＣＡの各ＯＡＭモードの受信信号の復調処理を行う処理手段３とを備える。   In the OAM multiplex communication system according to the second aspect of the invention, the interference removing means calculates interference signal power between each OAM mode of a plurality of UCAs, and when the maximum interference signal power is equal to or less than a predetermined threshold 3, between OAM modes. Processing means 1 for performing signal separation processing by equalization processing between the same OAM modes in each UCA, and performing demodulation processing of the received signal in each OAM mode after separation, and a plurality of UCA's Interference signal power between each OAM mode is calculated, and when the interference signal power is greater than the threshold 3 and the number of OAM mode pairs is less than or equal to the predetermined threshold 4, the OAM mode excluding the interference mode where the interference signal power is less than the threshold 3 is excluded Processing unit 2 that performs interference removal processing only between the two and performs demodulation processing of the received signal of each OAM mode of each UCA, and calculates interference signal power between each OAM mode of a plurality of UCAs If the interference signal power is greater than the threshold 3 and the number of OAM mode pairs is greater than the predetermined threshold 4, interference is performed using channel information between all received signals of each OAM mode of each UCA and all OAM modes of UCA. And processing means 3 for performing removal processing and performing demodulation processing of the received signal in each OAM mode of each UCA.

第２の発明のＯＡＭ多重通信システムにおいて、干渉除去手段は、所定の時間間隔ごとにすべてのＯＡＭモード間のチャネル情報を取得し、その区間は、所定の閾値３より大きい干渉を及ぼすＯＡＭモード間のみのチャネル情報を取得する構成である。   In the OAM multiplex communication system according to the second invention, the interference removing means acquires channel information between all the OAM modes at predetermined time intervals, and the section is between the OAM modes which exert interference larger than a predetermined threshold value 3 Channel information is acquired.

第３の発明は、送信装置のＵＣＡで複数のＯＡＭモードの信号を生成して送信し、受信装置のＵＣＡで複数のＯＡＭモードの信号を受信して分離し、ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信方法において、受信装置は、ＯＡＭモード間のチャネル情報を用いて、所定の閾値１より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う。   In the third invention, the UCA of the transmission apparatus generates and transmits a plurality of OAM mode signals, the UCA of the reception apparatus receives and separates the plurality of OAM mode signals, and spatially multiplexes the number of OAM mode signals. In the OAM multiplex communication method for transmission, the receiving apparatus determines between OAM modes which cause interference larger than a predetermined threshold 1 using channel information between OAM modes, and performs interference cancellation processing between the OAM modes.

第４の発明は、同心円状に配置した複数のＵＣＡからなるＭ−ＵＣＡを送信装置と受信装置に備え、送信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を生成して送信し、受信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を受信して分離し、ＵＣＡ数×ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信方法において、受信装置は、送信装置は各ＵＣＡの各ＯＡＭモード間のチャネル情報を用いて、各ＵＣＡで受信する同一ＯＡＭモード間の信号分離を行うとともに、所定の閾値３より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う。   The fourth invention comprises M-UCA consisting of a plurality of UCAs arranged concentrically in a transmitter and a receiver, and generates and transmits signals of a plurality of OAM modes in each UCA of the transmitter, and a receiver In an OAM multiplex communication method in which each UCA receives and separates a plurality of OAM mode signals and spatially multiplexes and transmits UCA number × OAM mode signals, the receiving apparatus is a transmitting apparatus corresponding to each OAM mode of each UCA. While performing signal separation between the same OAM mode received by each UCA using channel information between them, determine between OAM modes that cause interference larger than a predetermined threshold value 3 and perform interference removal processing between the OAM modes .

本発明により、ＯＡＭ多重通信システムにおいて、軸ズレやＲＦ回路の不完全性が生じる場合、多重数が増加しても、干渉除去処理に要する演算量の軽減ができる。また、チャネル情報取得の負荷を軽減することができる。これらにより、低演算量で、多重数を増やすことができ、伝送容量を向上する効果が得られる。   According to the present invention, in an OAM multiplex communication system, in the case where an axis shift or an imperfection of an RF circuit occurs, the amount of calculation required for the interference removal process can be reduced even if the number of multiplexes increases. Also, the load of channel information acquisition can be reduced. As a result, the number of multiplexing can be increased with a low amount of calculation, and the effect of improving the transmission capacity can be obtained.

本発明の第１の実施形態における送受信装置の概要を示す図である。It is a figure which shows the outline | summary of the transmission / reception apparatus in the 1st Embodiment of this invention. 第１の実施形態における受信装置のデジタル信号処理部23の構成例を示す図である。It is a figure which shows the structural example of the digital signal processing part 23 of the receiver in 1st Embodiment. 第１の実施形態における受信装置のデジタル信号処理部23の処理手順例を示すフローチャートである。It is a flowchart which shows the processing procedure example of the digital signal processing part 23 of the receiver in 1st Embodiment. 本発明の第２の実施形態における送受信装置の概要を示す図である。It is a figure which shows the outline | summary of the transmission / reception apparatus in the 2nd Embodiment of this invention. ＯＡＭモードの信号を生成するためのＵＣＡの位相設定例を示す図である。It is a figure which shows the example of a phase setting of UCA for producing | generating the signal of OAM mode. ＯＡＭ多重信号の位相分布と信号強度分布の例を示す図である。It is a figure which shows the example of phase distribution and signal strength distribution of OAM multiplexed signal. ＯＡＭ多重信号を分離するためのＵＣＡの位相設定例を示す図である。It is a figure which shows the example of a phase setting of UCA for isolate | separating an OAM multiplexed signal. ＯＡＭ多重通信システムのＭ−ＵＣＡの構成例を示す図である。It is a figure which shows the structural example of M-UCA of an OAM multiplex communication system.

以下に示す実施形態では、単一のＵＣＡまたはＭ−ＵＣＡで構成される送信アンテナと受信アンテナの中心は、ＧＰＳ情報やその他計測手法を用いてそれぞれの伝搬方向が一致し、送信アンテナと受信アンテナは伝搬直交平面に配置されるものとする。しかしながら、ＧＰＳ情報の誤差やそのたアンテナ配置の誤差により、送信アンテナと受信アンテナの中心のズレ（軸ズレ）が起こり得る場合を想定する。   In the embodiment shown below, the center of the transmitting antenna and receiving antenna composed of a single UCA or M-UCA matches their propagation directions using GPS information and other measurement methods, and the transmitting antenna and the receiving antenna Are arranged in the propagation orthogonal plane. However, it is assumed that a shift (axial shift) between the center of the transmitting antenna and the receiving antenna may occur due to an error in GPS information or an error in the antenna arrangement.

（第１の実施形態）
第１の実施形態は、ＯＡＭ通信における課題を解決する実施形態である。
図１は、本発明の第１の実施形態における送受信装置の概要を説明する。図１(1),(2) は、ＯＡＭモードｎ〜ＯＡＭモード−ｎを伝送する場合における送信装置と受信装置を示す。 First Embodiment
The first embodiment is an embodiment for solving the problem in the OAM communication.
FIG. 1 illustrates an overview of a transmitting and receiving apparatus in the first embodiment of the present invention. FIGS. 1 (1) and 1 (2) show a transmitter and a receiver in the case of transmitting the OAM mode n to the OAM mode-n.

図１(1) において、送信装置は、デジタル信号処理部１１、ＲＦ処理部１２、送信アンテナ部１３を備える。デジタル信号処理部１１は、データの変調や複数のＯＡＭモードで送信するストリーム生成などの通信に必要なデジタル信号処理を行う。ＲＦ処理部１２は、周波数変換、ＲＦフィルタリングなどのアナログ処理を行う。送信アンテナ部１３は、ＵＣＡにより複数のストリームを送信する。   In FIG. 1 (1), the transmission apparatus includes a digital signal processing unit 11, an RF processing unit 12, and a transmission antenna unit 13. The digital signal processing unit 11 performs digital signal processing necessary for communication such as modulation of data and stream generation to be transmitted in a plurality of OAM modes. The RF processing unit 12 performs analog processing such as frequency conversion and RF filtering. The transmission antenna unit 13 transmits a plurality of streams by UCA.

図１(2) において、受信装置は、受信アンテナ部２１、ＲＦ処理部２２、デジタル信号処理部２３を備える。受信アンテナ部２１は、ＵＣＡにより複数のＯＡＭモードの信号を受信する。ＲＦ処理部２２は、受信信号の周波数変換、ＲＦフィルタリングなどのアナログ処理を行う。   In FIG. 1 (2), the receiving apparatus includes a receiving antenna unit 21, an RF processing unit 22, and a digital signal processing unit 23. The receiving antenna unit 21 receives a plurality of OAM mode signals by the UCA. The RF processing unit 22 performs analog processing such as frequency conversion of received signals and RF filtering.

ここで、送信アンテナ部１３および受信アンテナ部２１は、ＯＡＭ通信の場合は、単一のＵＣＡで構成される。デジタル信号処理部２３は、ＳＩＣ等によりＯＡＭモード間の干渉除去処理を行う。チャネル推定を行う際には、送信装置のデジタル信号処理部１１は、既知信号を生成し送信し、受信装置のデジタル信号処理部２３は、この既知信号の情報を用いて，チャネル推定を行う。   Here, the transmission antenna unit 13 and the reception antenna unit 21 are configured by a single UCA in the case of the OAM communication. The digital signal processing unit 23 performs interference removal processing in the OAM mode by SIC or the like. When performing channel estimation, the digital signal processing unit 11 of the transmission device generates and transmits a known signal, and the digital signal processing unit 23 of the reception device performs channel estimation using the information of the known signal.

図２は、第１の実施形態における受信装置のデジタル信号処理部２３の構成例を示す。 図２において、デジタル信号処理部２３は、既知信号・データ信号分離部２３１と、チャネル推定部２３２と、干渉除去処理判定部２３３と、復調処理部２３４と、干渉除去処理部２３５から構成かれる。既知信号・データ信号分離部２３１は、ＲＦ処理部２２から入力した信号を既知信号とデータ信号に分離し、データ信号を復調処理部２３４に出力し、既知信号をチャネル推定部２３２に出力する。チャネル推定部２３２は、既知信号を用いてＯＡＭモード間のチャネル推定を行い、その結果を干渉除去処理判定部２３３と復調処理部２３４と干渉除去処理部２３５に出力する。   FIG. 2 shows a configuration example of the digital signal processing unit 23 of the receiving device in the first embodiment. In FIG. 2, the digital signal processing unit 23 includes a known signal / data signal separation unit 231, a channel estimation unit 232, an interference removal processing determination unit 233, a demodulation processing unit 234, and an interference removal processing unit 235. The known signal / data signal separation unit 231 separates the signal input from the RF processing unit 22 into a known signal and a data signal, outputs the data signal to the demodulation processing unit 234, and outputs the known signal to the channel estimation unit 232. The channel estimation unit 232 performs channel estimation in the OAM mode using the known signal, and outputs the result to the interference removal processing determination unit 233, the demodulation processing unit 234, and the interference removal processing unit 235.

干渉除去処理判定部２３３は、チャネル推定の結果と干渉除去処理部２３５の出力結果を参照し、干渉除去処理の有無を判定し、その結果をチャネル推定部２３２と、干渉除去処理部２３５と、復調処理部２３４に出力する。復調処理部２３４は、干渉除去処理判定部２３３の結果を参照し、チャネル推定結果を用いてデータ信号の復調処理を行い、その結果を外部に出力する。同時に、入力データと復調結果を干渉除去処理部２３５に出力する。干渉除去処理部２３５は、干渉除去処理判定部２３３の判定結果を参照し、チャネル推定の結果と復調処理部２３４の出力信号を用いて干渉除去処理を行う。   The interference removal processing determination unit 233 refers to the channel estimation result and the output result of the interference removal processing unit 235 to determine the presence or absence of the interference removal processing, and the result is a channel estimation unit 232, an interference removal processing unit 235, It outputs to the demodulation processing unit 234. Demodulation processing section 234 refers to the result of interference removal processing determination section 233, demodulates the data signal using the channel estimation result, and outputs the result to the outside. At the same time, the input data and the demodulation result are output to the interference removal processing unit 235. The interference removal processing unit 235 refers to the determination result of the interference removal processing determination unit 233, and performs interference removal processing using the channel estimation result and the output signal of the demodulation processing unit 234.

図３は、第１の実施形態における受信装置のデジタル信号処理部２３の処理手順を示す。
図２および図３において、既知信号・データ信号分離部２３１は、受信装置のＲＦ処理部２２から出力されるＯＡＭモードごとの信号を入力する（Ｓ11）。ここで、既知信号は、チャネル推定用既知信号や同期検出用の信号等のデータ信号以外のすべてのコントロール信号を表す。本発明の範囲外である同期検出等の処理は、この既知信号・データ信号分離部２３１において、あらかじめ決められている通信規格に沿って行われるものにする。本発明では、チャネル推定用の既知信号を対象とする。すなわち、既知信号・データ信号分離部２３１は、コントロール信号の内、チャネル推定用の既知信号をチャネル推定部２３２に出力し、コントロール信号以外のデータ信号を復調処理部２３４に出力する（Ｓ12）。ＯＦＤＭのように、ＦＦＴ処理が必要な場合は、既知信号・データ信号分離部２３１は、ＦＦＴ処理を行ってから既知信号とデータ信号に分離する。 FIG. 3 shows the processing procedure of the digital signal processing unit 23 of the receiving device in the first embodiment.
In FIG. 2 and FIG. 3, the known signal / data signal separation unit 231 inputs the signal for each OAM mode output from the RF processing unit 22 of the receiving apparatus (S11). Here, the known signal represents all control signals other than data signals such as known signals for channel estimation and signals for synchronization detection. Processing such as synchronization detection which is outside the scope of the present invention is performed in the known signal / data signal separation unit 231 in accordance with a predetermined communication standard. The present invention is directed to known signals for channel estimation. That is, the known signal / data signal separation unit 231 outputs the known signal for channel estimation among the control signals to the channel estimation unit 232, and outputs the data signal other than the control signal to the demodulation processing unit 234 (S12). When FFT processing is required, as in OFDM, the known signal / data signal separation unit 231 performs FFT processing and then separates the signal into a known signal and a data signal.

次に、チャネル推定部２３２は、既知信号・データ信号分離部２３１が出力するチャネル推定用の既知信号を用いてチャネル推定を行う（Ｓ13）。チャネル推定処理は、既知信号を用いて、すべてのＯＡＭモードからすべてのＯＡＭモードに対するチャネルに関し、ＺＦやＭＭＳＥ等の手法で行えばよい。チャネル推定部２３２は、このチャネル推定処理結果を干渉除去処理判定部２３３と復調処理部２３４に出力する。   Next, the channel estimation unit 232 performs channel estimation using the known signal for channel estimation output from the known signal / data signal separation unit 231 (S13). The channel estimation processing may be performed using a known signal with respect to channels from all OAM modes to all OAM modes by a method such as ZF or MMSE. The channel estimation unit 232 outputs the channel estimation processing result to the interference removal processing determination unit 233 and the demodulation processing unit 234.

干渉除去処理判定部２３３は、各ＯＡＭモード間のチャネル推定結果を用いて、各ＯＡＭモード間の干渉信号電力を計算する（Ｓ14）。この干渉信号電力は、チャネル推定の結果の値の絶対値の２乗等の尺度で計算すればよい。各ＯＡＭモード間の干渉信号電力の最大値である最大干渉信号電力が、所定の閾値１より大きいか否かを判定する（Ｓ15）。最大干渉信号電力≦閾値１の場合は、パターン１−１の復調処理を行う（Ｓ16）。最大干渉信号電力＞閾値１の場合は、各ＯＡＭモード間の干渉信号電力が閾値１より大きいＯＡＭモード組の数が、所定の閾値２より大きいか否かを判定する（Ｓ17, Ｓ18）。ＯＡＭモード組数≦閾値２の場合は、パターン１−２の復調処理を行う（Ｓ19）。ＯＡＭモード組数＞閾値２の場合は、パターン１−３の処理を行う（Ｓ23）。   The interference removal processing determination unit 233 calculates interference signal power between the OAM modes using the channel estimation result between the OAM modes (S14). The interference signal power may be calculated on a scale such as the square of the absolute value of the channel estimation result. It is determined whether or not the maximum interference signal power, which is the maximum value of interference signal power between the OAM modes, is larger than a predetermined threshold 1 (S15). If maximum interference signal power ≦ threshold 1, demodulation processing of pattern 1-1 is performed (S16). If the maximum interference signal power> threshold value 1, it is determined whether the number of OAM mode pairs in which the interference signal power between the OAM modes is greater than threshold value 1 is greater than a predetermined threshold value 2 (S17, S18). If the number of sets of OAM modes ≦ the threshold 2, demodulation processing of pattern 1-2 is performed (S19). If the number of sets of OAM modes> the threshold 2, processing of pattern 1-3 is performed (S23).

このパターン１−１，パターン１−２，パターン１−３の判定結果は、チャネル推定部２３２と復調処理部２３４と干渉除去処理部２３５に入力する。   The determination results of the pattern 1-1, the pattern 1-2 and the pattern 1-3 are input to the channel estimation unit 232, the demodulation processing unit 234 and the interference removal processing unit 235.

すなわち、パターン１−１の復調処理（Ｓ16）では、受信側における各ＯＡＭモード間の最大干渉信号電力が所定の閾値１以下の場合に、ＯＡＭモード間の独立性が保たれていると判断し、ＯＡＭモード間の干渉除去処理を行わずに、各ＯＡＭモードの受信信号の復調処理を行う。   That is, in the demodulation process (S16) of pattern 1-1, it is determined that the independence between the OAM modes is maintained when the maximum interference signal power between the OAM modes on the reception side is less than or equal to the predetermined threshold 1. Demodulation processing of the received signal in each OAM mode is performed without performing interference cancellation processing in the OAM mode.

パターン１−２の復調処理（Ｓ19）では、受信側における各ＯＡＭモード間の最大干渉信号電力が所定の閾値１より大きく、かつ干渉信号電力が閾値１より大きいＯＡＭモード組数が所定の閾値２以下の場合に、まずＯＡＭモード間の干渉除去処理を行わずに各ＯＡＭモードの受信信号の復調を行う。次に、復調した信号を用いて元の信号のレプリカを生成し（Ｓ20）、このレプリカとチャネル推定情報を用いて、各ＯＡＭモード間でＳＩＣ等の手法により干渉除去処理を行い（Ｓ21）、その後に各ＯＡＭモードの受信信号の復調処理を行う（Ｓ22）。このとき、演算量の削減のため、干渉信号電力が閾値１以下ＯＡＭモード間の干渉除去処理は行わない。これは、それらのＯＡＭモード間の干渉は小さいため、干渉除去処理をしなくても、性能劣化は許容範囲に収まるためである。   In the demodulation process (S19) of pattern 1-2, the maximum interference signal power between each OAM mode on the reception side is larger than a predetermined threshold 1 and the number of OAM mode groups whose interference signal power is larger than the threshold 1 is a predetermined threshold 2 In the following cases, first, the received signal of each OAM mode is demodulated without performing the interference removal process between the OAM modes. Next, a replica of the original signal is generated using the demodulated signal (S20), and using this replica and channel estimation information, interference removal processing is performed between each of the OAM modes by a method such as SIC (S21), Thereafter, demodulation processing of the received signal in each OAM mode is performed (S22). At this time, in order to reduce the amount of calculation, the interference removal process is not performed between the OAM modes where the interference signal power is less than or equal to the threshold value 1. This is because the interference between the OAM modes is small, and the performance degradation is within the allowable range without the interference cancellation process.

パターン１−３の処理では、受信側における各ＯＡＭモード間の最大干渉信号電力が所定の閾値１より大きく、かつ干渉信号電力が閾値１より大きいＯＡＭモード組数が所定の閾値２より大きい場合に、各ＯＡＭモードのすべての受信信号とすべてのＯＡＭモード間のチャネル情報を用いて、ＺＦ等の等化手法により干渉除去処理を行い（Ｓ23）、その後に各ＯＡＭモードの受信信号の復調処理を行う（Ｓ24）。   In the processing of pattern 1-3, when the maximum interference signal power between each OAM mode on the reception side is larger than a predetermined threshold 1 and the interference signal power is larger than the threshold 1 and the number of OAM mode pairs is larger than a predetermined threshold 2 Performing interference cancellation processing by an equalization method such as ZF using channel information between all received signals in each OAM mode and all OAM modes (S23), and then demodulating the received signals in each OAM mode Perform (S24).

ここで、チャネル推定部２３２は、パターン１−１とパターン１−２の場合、復調処理と干渉除去処理に必要なチャネルのみのチャネル推定処理を行うことで、演算量を削減する。すなわち、あらかじめ決められた周期ごとには、すべてのＯＡＭモードのすべてのＯＡＭモードに対するチャネル推定処理を行うが、その周期内では、復調処理と干渉除去処理に必要なチャネルのみのチャネル推定処理を行う。例えば、パターン１−１の場合、チャネル情報取得の負荷を削減するため、異なるＯＡＭモード間のチャネル推定処理を省略してもよい。また、パターン１−２の場合も、ＳＩＣ処理を行わないＯＡＭモード間のチャネル推定処理を省略してもよい。このようにチャネル推定部２３２が必要なチャネルの推定処理のみを行う場合、干渉除去処理判定部２３３は、チャネル推定部２３２が行ったチャネル推定計算結果のみを用いて、パターン１−１〜１−３の判定を行う。   Here, in the case of the pattern 1-1 and the pattern 1-2, the channel estimation unit 232 reduces the amount of computation by performing channel estimation processing of only channels necessary for demodulation processing and interference removal processing. That is, although channel estimation processing for all OAM modes in all OAM modes is performed in a predetermined cycle, channel estimation processing for only channels necessary for demodulation processing and interference removal processing is performed in that cycle. . For example, in the case of pattern 1-1, channel estimation processing between different OAM modes may be omitted to reduce the load of channel information acquisition. Also in the case of pattern 1-2, channel estimation processing between OAM modes in which SIC processing is not performed may be omitted. As described above, when the channel estimation unit 232 performs only the required channel estimation processing, the interference removal processing determination unit 233 uses only the channel estimation calculation result performed by the channel estimation unit 232, and uses patterns 1-1 to 1-1-. Make a judgment of 3.

（復調処理部２３４の動作）
次に、復調処理部２３４の動作について詳しく説明する。復調処理部２３４は、既知信号・データ信号分離部２３１が出力するデータ信号と、チャネル推定部２３２が出力するチャネル情報を用いて復調処理を行う。ここで、干渉除去処理判定部２３３から復調処理部２３４にパターン１−１の結果が入力すると、他のＯＡＭモードからの干渉除去処理を行わずに、各ＯＡＭモードの受信信号の復調処理を行う。 (Operation of the demodulation processing unit 234)
Next, the operation of the demodulation processing unit 234 will be described in detail. The demodulation processing unit 234 performs demodulation processing using the data signal output from the known signal / data signal separation unit 231 and the channel information output from the channel estimation unit 232. Here, when the result of pattern 1-1 is input from the interference removal processing determination unit 233 to the demodulation processing unit 234, demodulation processing of received signals of each OAM mode is performed without performing interference removal processing from other OAM modes. .

また、干渉除去処理判定部２３３にパターン１−２の結果が入力すると、まず各ＯＡＭモードの受信信号の復調処理を行い、その結果を干渉除去処理部２３５に出力する。また、パターン１−２の場合は、既知信号・データ信号分離部２３１が復調処理部２３４に出力したデータ信号も合わせて干渉除去処理部２３５に出力する。ここで、干渉除去処理部２３５は、各ＯＡＭモード間でＳＩＣ等の手法により干渉除去処理を行い、その結果を再び復調処理部２３４に入力する。復調処理部２３４は、干渉除去処理部２３５から入力する信号を用いて、再び各ＯＡＭモードの復調処理を行う。この過程を繰り返すことで、干渉除去処理の性能を向上することができる。この繰り返し処理において、繰り返しの数は、あらかじめ決められた数分だけ行うこともできるし、干渉除去処理部２３５が繰り返し処理をする中で、ｎ回目のレプリカとｎ＋１回目のレプリカの差があらかじめ決められた閾値より小さくなると繰り返し処理を終了することもできる。   Also, when the result of pattern 1-2 is input to the interference removal processing determination unit 233, first, demodulation processing of the received signal of each OAM mode is performed, and the result is output to the interference removal processing unit 235. In the case of pattern 1-2, the data signal output from the known signal / data signal separation unit 231 to the demodulation processing unit 234 is also output to the interference removal processing unit 235. Here, the interference removal processing unit 235 performs interference removal processing between each of the OAM modes by a method such as SIC, and inputs the result again to the demodulation processing unit 234. The demodulation processing unit 234 performs demodulation processing of each OAM mode again using the signal input from the interference removal processing unit 235. By repeating this process, the performance of the interference removal process can be improved. In this repetitive processing, the number of repetitions can be performed by a predetermined number, and while the interference removal processing unit 235 repeatedly performs processing, the difference between the nth replica and the n + 1th replica is determined in advance. If it becomes smaller than the threshold, it is possible to end the iterative process.

また、干渉除去処理判定部２３３にパターン１−３の結果が入力すると、各ＯＡＭモード間のチャネル情報を用いて、ＺＦやＭＭＳＥ法により等化処理を行い、干渉除去処理を行ってから、各ＯＡＭモードの受信信号の復調処理を行う。   In addition, when the result of pattern 1-3 is input to the interference removal processing determination unit 233, equalization processing is performed by ZF or MMSE using channel information between each OAM mode, and interference removal processing is performed. Demodulates the received signal in the OAM mode.

（干渉除去処理部２３５の動作）
次に、干渉除去処理部２３５の動作について詳しく説明する。干渉除去処理部２３５は、干渉除去処理判定部２３３からパターン１−２の結果が入力すると、復調処理部２３４からの入力信号と、チャネル推定部２３２からのチャネル推定結果を用いて、干渉除去処理を行う。ここで、干渉除去処理判定部２３３の判定結果がパターン１−２の場合、干渉除去処理を要するＯＡＭモード組に関する情報を干渉除去処理部２３５に入力する。また、チャネル推定部２３２は、このパターン１−２の場合、干渉除去処理を要するＯＡＭモード組のみのチャネル推定結果を干渉除去処理部２３５に入力してもよい。干渉除去処理部２３５は、まず復調処理部２３４が出力する復調後の信号とチャネル推定結果を用いて、元の信号のレプリカを生成する。ここで生成するレプリカは、干渉を及ぼすと判断されるＯＡＭモード組のみを生成すればよい。例えば、ＯＡＭモード１からＯＡＭモード２への干渉量が閾値１より高い場合、ＯＡＭモード１の復調信号と、ＯＡＭモード１からＯＡＭモード２へのチャネル情報を用いて、ＯＡＭモード１からＯＡＭモード２への干渉に相当するレプリカを生成する。 (Operation of the interference removal processing unit 235)
Next, the operation of the interference removal processing unit 235 will be described in detail. When the interference removal processing unit 235 receives the result of pattern 1-2 from the interference removal processing determination unit 233, interference removal processing is performed using the input signal from the demodulation processing unit 234 and the channel estimation result from the channel estimation unit 232. I do. Here, when the determination result of the interference removal processing determination unit 233 is the pattern 1-2, the information on the OAM mode set requiring the interference removal processing is input to the interference removal processing unit 235. Further, in the case of this pattern 1-2, the channel estimation unit 232 may input, to the interference removal processing unit 235, the channel estimation result of only the OAM mode set requiring the interference removal processing. The interference removal processing unit 235 first generates a replica of the original signal using the signal after demodulation and the channel estimation result output from the demodulation processing unit 234. The replica generated here needs to generate only the OAM mode set determined to exert interference. For example, when the amount of interference from OAM mode 1 to OAM mode 2 is higher than the threshold 1, OAM mode 1 to OAM mode 2 can be obtained using the demodulated signal of OAM mode 1 and channel information from OAM mode 1 to OAM mode 2. Create a replica that corresponds to the interference with

次に、データ信号のＯＡＭモード２の信号からこのレプリカを引き算する。このように、干渉除去処理の対象となるＯＡＭモードのレプリカを生成し、データ信号から引き算した結果を再び復調処理部２３４に出力する。復調処理部２３４は、干渉除去処理部２３５から入力する信号を用いて改めて復調処理を行い、その復調結果を再び干渉除去処理部２３５に入力する。このような過程を繰り返すことにより、干渉除去性能を改善する。この繰り返し処理は、前述のようにあらかじめ決めた数の繰り返し後に終了してもよいし、元のデータ信号からレプリカ信号の引き算後の信号の、各繰り返し過程の差を計算し、その差があらかじめ決めた閾値より小さくなると、繰り返し処理を終了してもよい。また、繰り返しＳＩＣ処理に一般的に使われる終了法により終了してもよい。   Next, this replica is subtracted from the signal of OAM mode 2 of the data signal. As described above, the replica of the OAM mode to be subjected to the interference removal processing is generated, and the result of subtraction from the data signal is output again to the demodulation processing unit 234. The demodulation processing unit 234 performs demodulation processing again using the signal input from the interference removal processing unit 235, and inputs the demodulation result to the interference removal processing unit 235 again. Repeating such a process improves the interference removal performance. This repetition process may be ended after repeating a predetermined number as described above, or the difference between each repetition process of the signal after subtraction of the replica signal is calculated from the original data signal, and the difference is calculated in advance. If it becomes smaller than the determined threshold value, the iterative process may end. Also, it may be terminated by the termination method generally used for repetitive SIC processing.

以下、第１の実施形態の処理について数式を用いて説明する。以下の例では、５個のＯＡＭモード−２，−１，０，１，２を用いてＯＡＭ通信を行う場合を想定する。なお、送信信号をＸi とし、受信信号をＹj とする。ここで、ｉとｊは、ＯＡＭモードの次数を表す。また、送信ＯＡＭモードｉと受信ＯＡＭモードｊ間のチャネルをＨj,i と表す。なお、送受信信号は、ＯＦＤＭ方式等のように周波数領域にてデータ変復調を行う通信方式を想定するが、ＳＣ（single carrier）方式等のように時間領域にてデータを変復調する通信方式への適用も同様に可能である。   The process of the first embodiment will be described below using formulas. In the following example, it is assumed that OAM communication is performed using five OAM modes -2, -1, 0, 1, and 2. Note that the transmission signal is Xi, and the reception signal is Yj. Here, i and j represent the order of the OAM mode. Further, a channel between the transmission OAM mode i and the reception OAM mode j is denoted as Hj, i. In addition, although the transmission / reception signal assumes the communication system which performs data modulation / demodulation in a frequency domain like OFDM system etc., application to the communication system which modulates / demodulates data in a time domain like SC (single carrier) system etc. Is also possible.

受信装置のＲＦ処理部２２の出力信号は、以下の式(1) のようになる。ここでは、ＯＦＤＭの複数のキャリアの内、１個のサブキャリアについて記述するが、他のサブキャリアの同様の手法を適用すればよい。なお、送信側がチャネル推定用の信号とデータ信号を時系列に交互に分けて送信する場合は、チャネル推定用の信号間では、チャネルの変動はないと想定する。すなわち、チャネル推定用の信号を用いてチャネル推定を行ってからそのチャネル推定結果を用いて、データ信号の干渉分離・等化・復調処理を行う際には、チャネル情報は変わらないと想定する。また、チャネル推定用の信号とデータ信号の周波数領域に分けて伝送する場合、すなわち、複数のサブキャリアの内、一部のサブキャリアで既知信号を送信し、残りのサブキャリアでデータ信号を送信する場合は、既知信号を用いてチャネル推定を行い、その結果から内挿（interpolation ）等の手法によりデータ信号のサブキャリアのチャネル推定を行うものとする。なお、時間領域と周波数領域を合わせて既知信号を挿入する方式も同様に既知信号を用いてチャネル推定を行い、周波数領域では、内挿等によりデータ信号のサブキャリアのチャネル推定を行い、時間領域では、次回の既知信号と間ではチャネルは変わらないと想定してもよい。   The output signal of the RF processing unit 22 of the receiving apparatus is expressed by the following equation (1). Here, although one subcarrier is described among a plurality of carriers of OFDM, the same method of other subcarriers may be applied. When the transmitting side alternately transmits the channel estimation signal and the data signal in time series, it is assumed that there is no channel fluctuation between the channel estimation signals. That is, it is assumed that the channel information does not change when performing interference separation / equalization / demodulation processing of the data signal after performing channel estimation using a signal for channel estimation and using the channel estimation result. Also, in the case of separately transmitting in the frequency domain of a signal for channel estimation and a data signal, that is, a known signal is transmitted on some of the plurality of subcarriers, and a data signal is transmitted on the remaining subcarriers. In this case, channel estimation is performed using a known signal, and from the result, channel estimation of subcarriers of a data signal is performed by a method such as interpolation. Similarly, in the method of inserting the known signal by combining the time domain and the frequency domain, channel estimation is performed using the known signal, and in the frequency domain, channel estimation of subcarriers of the data signal is performed by interpolation etc. Then, it may be assumed that the channel does not change between the next known signal.

なお、既知信号とデータ信号の挿入の方法は、本発明の範囲外の各種類の無線通信方式を採用すると想定する。一般的に使われるの無線通信方式は、既知信号でチャネル推定を行い、内挿やチャネルが変動しない前提で、その推定したチャネル情報を用いてデータ信号の等化処理を行っても問題が生じないように設計されているため、前述のように想定してもよい。   In addition, it is assumed that the method of insertion of a known signal and a data signal employ | adopts the wireless communication system of each kind besides the scope of the present invention. In a commonly used wireless communication system, channel estimation is performed with known signals, and problems occur even if data signal equalization processing is performed using the estimated channel information on the assumption that interpolation or channel fluctuation does not occur. Because it is designed not to be, it may be assumed as described above.

Figure 2019083475
Figure 2019083475

ここで、Ｎk は、受信側のＯＡＭモードｋでの雑音を表す。既知信号・データ信号分離部２３１は、式(1) が表す受信信号の内、チャネル推定用の既知信号とデータ信号を分離し、チャネル推定部２３２に入力する。チャネル推定用の送信信号、すなわち、式(1) のＸi が既知であるため、チャネル推定部２３２は受信信号と既知信号を用いて、ＺＦ方法等にチャネル推定を行うことができる。この動作によりすべてのＨj,i の推定ができる。このチャネル推定処理の結果は、干渉除去処理判定部２３３に入力される。   Here, Nk represents noise in the OAM mode k on the receiving side. The known signal / data signal separation unit 231 separates the known signal for channel estimation and the data signal among the reception signals represented by equation (1), and inputs the separated signal to the channel estimation unit 232. Since the transmission signal for channel estimation, that is, Xi in equation (1) is known, the channel estimation unit 232 can perform channel estimation in the ZF method or the like using the received signal and the known signal. This operation can estimate all Hj, i. The result of the channel estimation process is input to the interference removal process determination unit 233.

干渉除去処理判定部２３３は、すべてのＨj,i の絶対値（もしくは絶対値の２乗）と、あらかじめ決められた閾値１との比較を行い、パターン１−１、パターン１−２、パターン１−３の判定を行う。   The interference removal processing determination unit 233 compares the absolute value (or the square of the absolute value) of all Hj, i with the threshold value 1 determined in advance, and determines the pattern 1-1, the pattern 1-2, the pattern 1 Perform the judgment of -3.

パターン１−１の場合は、他のＯＡＭモードからの干渉を無視してもよいため、復調処理部２３４は、同一ＯＡＭモード間のチャネル情報のみを用いて、チャネル等化処理を行ってから、既知信号・データ信号分離部２３１から入力するデータ信号に対して復調処理を行う。例えば、ＺＦによる等化処理の場合、式(2) の復調処理を行う。次に、その結果であるを用いて復調処理を行う。式(2) のＸi は、ＯＡＭモードｉの送信信号の等化処理後の値を表し、式(3) のＸi は、式(2) のＸi の復調後の信号を表す。なお、Ｘの上につく「＾」や「・」は文中では省略している（以下同様）。また、demod( )は、チャネル符号の復号処理等を含む復調処理を表す。   In the case of pattern 1-1, since the interference from other OAM modes may be ignored, the demodulation processing unit 234 performs channel equalization processing using only channel information between the same OAM modes. A demodulation process is performed on the data signal input from the known signal / data signal separation unit 231. For example, in the case of equalization processing by ZF, demodulation processing of equation (2) is performed. Next, demodulation processing is performed using the result. Xi in equation (2) represents the value after equalization processing of the transmission signal of OAM mode i, and Xi in equation (3) represents the signal after demodulation of Xi in equation (2). In addition, "^" and "." Placed on top of X are omitted in the sentence (the same applies to the following). Also, demod () represents a demodulation process including a channel code decoding process and the like.

Figure 2019083475
Figure 2019083475

Figure 2019083475
Figure 2019083475

パターン１−２の場合は、まず式(2) のように他の干渉を無視してから各ＯＡＭモードの等化処理と復調処理を行い、それらの結果を用いて、レプリカを生成し、干渉除去処理の対象となるＯＡＭモード組の干渉除去処理を行う。ここで、干渉除去処理の対象でないＯＡＭモード間の干渉は雑音とみなす。   In the case of pattern 1-2, first ignore other interference as shown in equation (2), then perform equalization processing and demodulation processing of each OAM mode, and using these results, a replica is generated, and interference is generated. The interference removal processing of the OAM mode set to be the removal processing is performed. Here, interference between OAM modes that are not targets of interference cancellation processing is regarded as noise.

例えば、干渉除去処理の対象となるＯＡＭモード組が、(-2,0)、(-2,2)、(-1,1)、(0,-2)、(0,2) 、(1,-1)、(2,-2)の場合を示す。ここで、(i,j) は、送信ＯＡＭモードｉから受信ＯＡＭモードｊへの干渉を表す。この場合、ＳＩＣ処理の対象となる式を式(4) に示す。   For example, the OAM mode set to be subjected to the interference removal process is (−2, 0), (−2, 2), (−1, 1), (0, −2), (0, 2), (1 , -1) and (2, -2). Here, (i, j) represents the interference from the transmission OAM mode i to the reception OAM mode j. In this case, the equation to be subjected to the SIC process is shown in equation (4).

Figure 2019083475
Figure 2019083475

ここで、干渉除去処理の対象でないＯＡＭモード間の干渉は雑音とみなしたため、式(1) の中の干渉除去処理の対象でないＯＡＭモード間の干渉を表す項は、式(4）では雑音と
して表現されている。すなわち、（Ｎj)’は、雑音とみなされた干渉を含む受信ＯＡＭモ
ードｊの雑音を表す。ＳＩＣ処理後の信号は式(5) のように計算する。 Here, since the interference between the OAM modes not targeted for the interference removal processing is regarded as noise, a term representing the interference between the OAM modes not targeted for the interference cancellation processing in the equation (1) is referred to as noise in the equation (4). It is expressed. That is, (N j) ′ represents the noise of received OAM mode j including interference considered as noise. The signal after SIC processing is calculated as in equation (5).

Figure 2019083475
Figure 2019083475

ここで、mod(Ｘi ）は、送信側のＯＡＭモードｉの信号のレプリカである。なお、mod(Ｘi ）は、送信装置が行ったチャネル符号化処理を含む変調処理を表す。次に、干渉除去処理は、式(5) の計算結果（Ｙ-2，Ｙ-1，Ｙ0 ，Ｙ1 ，Ｙ2 ）を復調処理部２３４に入力する。信号復調部２３４は、式(6) のように等化処理を行う。次に、式(6) の結果を用いて、式(3) で表す復調処理を改めて行う。   Here, mod (Xi) is a replica of the signal of OAM mode i on the transmitting side. Mod (Xi) represents modulation processing including channel coding processing performed by the transmission apparatus. Next, in the interference removal processing, the calculation result (Y-2, Y-1, Y0, Y1, Y2) of the equation (5) is input to the demodulation processing unit 234. The signal demodulation unit 234 performs equalization processing as shown in equation (6). Next, using the result of equation (6), the demodulation process represented by equation (3) is performed again.

Figure 2019083475
Figure 2019083475

このパターン１−２では、このような復調処理とレプリカ生成による干渉処理を繰り返して行う。繰り返しの終了は、前記のように所定回数だけ行ってもよいし、前回の繰り返し処理から、次の繰り返し処理の結果の差分が一定値以内になるまで続けてもよい。たとえば、式(5) のＹj 、もしくは式(2) のＸi または式(3) のＸi の差分から、繰り返し処理の終了を判断してもよい。また、このＳＩＣ処理に必要なチャネルのみの推定処理を行うことで、チャネル推定の演算量を軽減することができる。   In this pattern 1-2, such demodulation processing and interference processing by replica generation are repeatedly performed. The end of the repetition may be performed a predetermined number of times as described above, or may be continued until the difference between the result of the previous repetition and the result of the next repetition is within a predetermined value. For example, the end of the iterative process may be determined from the difference between Yj in equation (5) or Xi in equation (2) or Xi in equation (3). Further, the amount of computation of channel estimation can be reduced by performing estimation processing of only the channel necessary for this SIC processing.

パターン１−３の場合は、式(1) のすべての項を用いて、ＺＦやＭＭＳＥ等によりすべてのＯＡＭモードの信号に対し、同時に等化処理を行ってから、各ＯＡＭモードの復調処理を行う。   In the case of pattern 1-3, equalization processing is performed simultaneously on all OAM mode signals by ZF, MMSE, etc. using all terms of equation (1), and then demodulation processing of each OAM mode is performed. Do.

このように、軸ズレやＲＦの不完全性によりＯＡＭモード間の干渉が生じた場合、本発明により各ＯＡＭモード間の干渉量を考慮して、その処理を要するＯＡＭモード間のみで行うことにより、干渉除去に必要な演算量を削減することができる。また、チャネル推定の演算量の削減も可能となる。特に、ＧＰＳや工学位置調整器なのにより、荒い軸ズレはできたが、精密な軸合わせができなかった場合等、パターン１−２が主となる無線通信環境では、特に演算量の削減効果が大きくなる。また、チャネルの時変動により。パターン１−１，１−２，１−３が時変動する場合、本発明によりチャネル状況に合わせて、適切にＯＡＭモード間干渉除去処理を行うことができるため、常に干渉除去処理をしない手法に比べて性能改善効果が得られ、また、常にすべてのＯＡＭモードに対する干渉除去処理を行う手法に比べて、演算量削減ができる。   As described above, when interference between OAM modes occurs due to axial misalignment or RF incompleteness, the present invention takes into consideration the amount of interference between each OAM mode and performs the processing only between OAM modes that require processing. The amount of computation required for interference removal can be reduced. In addition, it is possible to reduce the amount of computation of channel estimation. In particular, in a wireless communication environment in which pattern 1-2 is the main factor, such as when the precise axis alignment can not be performed due to rough alignment due to GPS or an engineering position adjuster, the amount of computation is particularly reduced. growing. Also, due to the time variation of the channel. When patterns 1-1, 1-2, and 1-3 vary with time, according to the present invention, it is possible to perform inter-OAM mode interference removal processing appropriately according to the channel conditions, so a method that does not always perform interference removal processing Compared with the above, the performance improvement effect can be obtained, and the amount of calculation can be reduced as compared with the method in which the interference removal process is always performed for all the OAM modes.

（閾値１と閾値２の設定例）
閾値１と閾値２は、ＯＡＭ通信の要求性能、チャネルの特性等を考慮し、本発明と別途の手法で決めればよい。 (Setting example of threshold 1 and threshold 2)
The threshold 1 and the threshold 2 may be determined by a method different from the present invention in consideration of the required performance of the OAM communication, the channel characteristics, and the like.

例えば、閾値１は、あらかじめ決められているＳＩＲ（signal to interference ratio; 干渉と信号の電力比率）から決めることができる。例えば、ＳＩＮＲが10dB以上必要となる設計されたシステムの場合は、閾値１は、信号電力より10dB低くなるように設定される。   For example, the threshold 1 can be determined from a predetermined signal to interference ratio (SIR). For example, in the case of a designed system requiring a SINR of 10 dB or more, the threshold 1 is set to be 10 dB lower than the signal power.

閾値２は、すべてのＯＡＭモードの等化処理を行う場合と、ＳＩＣ処理を行う場合の演算量を比較し、ＳＩＣ処理をする場合の演算量が大きくならないように設定することができる。例えば、５個のＯＡＭモードを用いて通信をする場合、すべてのＯＡＭモードを用いる等化処理の演算量は、ＯＡＭモード数５の３乗で 125となる。ＳＩＣ処理の演算量はＳＩＣ処理の手法により異なるが、例えばＳＩＣ処理の対象のＯＡＭモード数の 3.5乗の手法を使う場合の等化処理の演算量は、ＳＩＣ処理の対象のＯＡＭモード数４の 3.5乗で 128となり、５個すべてのＯＡＭモードを用いる等化処理の演算量 125より大きくなるため、閾値２は「３」と設定される。   The threshold value 2 can be set so that the amount of calculation in the case of performing the SIC processing does not increase by comparing the amount of calculation in the case of performing the equalization processing in all the OAM modes and the case of performing the SIC processing. For example, when communication is performed using five OAM modes, the amount of calculation of equalization processing using all the OAM modes is 125, which is the third power of five OAM modes. Although the amount of calculation of SIC processing varies depending on the method of SIC processing, for example, the amount of calculation of equalization processing in the case of using the method of 3.5 powers of the number of OAM modes targeted for SIC processing is four OAM modes for target SIC processing. The threshold 2 is set to “3” because the power of 3.5 is 128, which is larger than the operation amount 125 of equalization processing using all five OAM modes.

（第２の実施形態）
第２の実施形態は、ＯＡＭ−ＭＩＭＯ通信における課題を解決する実施形態である。
図４は、本発明の第２の実施形態における送受信装置の概要を説明する。図４(1),(2) は、複数のＵＣＡを用いて、かつ各ＵＣＡがＯＡＭモードｎからＯＡＭモード−ｎを伝送する場合における送信装置と受信装置を示す。 Second Embodiment
The second embodiment is an embodiment for solving the problem in OAM-MIMO communication.
FIG. 4 explains the outline of the transmitting and receiving apparatus in the second embodiment of the present invention. FIGS. 4 (1) and 4 (2) show a transmitter and a receiver in the case where each UCA transmits an OAM mode n to an OAM mode n using a plurality of UCAs.

図４(1) において、送信装置は、デジタル信号処理部３１、ＲＦ処理部３２、送信アンテナ部３３を備える。デジタル信号処理部３１は、データの変調や複数のＵＣＡ＃１〜＃ｍから送信する各ＯＡＭモードの信号生成などの通信に必要なデジタル信号処理を行う。ＲＦ処理部３２は、周波数変換、ＲＦフィルタリングなどのアナログ処理を行う。送信アンテナ部３３は、複数のＵＣＡ＃１〜＃ｍから各ＯＡＭモードの信号を送信する。   In FIG. 4 (1), the transmission apparatus includes a digital signal processing unit 31, an RF processing unit 32, and a transmission antenna unit 33. The digital signal processing unit 31 performs digital signal processing necessary for communication such as modulation of data and signal generation of each OAM mode transmitted from the plurality of UCAs # 1 to #m. The RF processing unit 32 performs analog processing such as frequency conversion and RF filtering. The transmitting antenna unit 33 transmits signals in each of the OAM modes from the plurality of UCAs # 1 to #m.

図４(2) において、受信装置は、受信アンテナ部４１、ＲＦ処理部４２、デジタル信号処理部４３を備える。受信アンテナ部４１は、複数のＵＣＡ＃１〜＃ｍで各ＯＡＭモードの信号を受信する。ＲＦ処理部３２は、周波数変換、ＲＦフィルタリングなどのアナログ処理を行う。   In FIG. 4 (2), the receiving apparatus includes a receiving antenna unit 41, an RF processing unit 42, and a digital signal processing unit 43. The receiving antenna unit 41 receives signals in each of the OAM modes by a plurality of UCAs # 1 to #m. The RF processing unit 32 performs analog processing such as frequency conversion and RF filtering.

第２の実施形態では、Ｍ−ＵＣＡを構成するＵＣＡごとに、第１の実施形態と同様のＲＦ処理部３２，４２、送信アンテナ部３３および受信アンテナ部４１を備え、デジタル信号処理部４３にて本実施形態に必要な信号分離・等化・干渉除去・復調処理を行う構成でもよい。   In the second embodiment, the RF processing units 32 and 42, the transmitting antenna unit 33, and the receiving antenna unit 41 similar to those of the first embodiment are provided for each UCA configuring the M-UCA. The configuration may be such that signal separation / equalization / interference removal / demodulation processing necessary for this embodiment is performed.

ここで、送信アンテナ部３３および受信アンテナ部４１は、ＯＡＭ−ＭＩＭＯ通信の場合は、Ｍ−ＵＣＡで構成される。複数のＵＣＡ＃１〜＃ｍが送信する同一ＯＡＭモードの複数の信号を、デジタル信号処理部４３がＯＡＭモードごとにＺＦやＭＭＳＥ手法などによる等化処理により分離する。また、第１の実施形態のパターン１−２と同様のパターン２−２の場合は、ＳＩＣ等による干渉除去処理を行う。チャネル推定を行う際には、送信装置のデジタル信号処理部３１が既知信号を生成し送信し、受信装置のデジタル信号処理部４３がこの既知信号の情報を用いて，チャネル推定を行う。また、第１の実施形態のパターン１−３と同様のパターン２−３の場合は、すべてのＵＣＡのすべてのＯＡＭモードを用いて干渉除去処理を行う。   Here, the transmission antenna unit 33 and the reception antenna unit 41 are configured by M-UCA in the case of the OAM-MIMO communication. The digital signal processing unit 43 separates a plurality of signals in the same OAM mode transmitted by the plurality of UCAs # 1 to #m by equalization processing using ZF, MMSE, or the like for each OAM mode. Moreover, in the case of the pattern 2-2 similar to the pattern 1-2 of the first embodiment, the interference removal processing by the SIC or the like is performed. When channel estimation is performed, the digital signal processing unit 31 of the transmission device generates and transmits a known signal, and the digital signal processing unit 43 of the reception device performs channel estimation using information on the known signal. In the case of the pattern 2-3 similar to the pattern 1-3 of the first embodiment, the interference removal process is performed using all the OAM modes of all the UCAs.

受信装置のデジタル信号処理部４３の構成は、図２に示す第１の実施形態のデジタル信号処理部２３と同様である。受信装置のデジタル信号処理部４３の処理手順は、図３に示す第１の実施形態の処理手順と同様である。ただし、閾値１を閾値３、閾値２を閾値４と読み替える。   The configuration of the digital signal processing unit 43 of the receiving apparatus is the same as that of the digital signal processing unit 23 of the first embodiment shown in FIG. The processing procedure of the digital signal processing unit 43 of the receiving device is the same as the processing procedure of the first embodiment shown in FIG. However, threshold 1 is replaced with threshold 3 and threshold 2 is replaced with threshold 4.

以下、図２および図３を参照して、第２の実施形態の動作例について説明する。受信装置のＲＦ処理部４２の出力信号は、デジタル信号処理部４３の既知信号・データ信号分離部２３１に入力する。ここで、すべてのＵＣＡのすべてのＯＡＭモードの信号は、既知信号・データ信号分離部２３１に入力し、既知信号はすべてのＵＣＡのすべてのＯＡＭモード毎に、異なるチャネル推定用既知信号や同期検出用のコントロール信号等で構成される。   An operation example of the second embodiment will be described below with reference to FIGS. 2 and 3. The output signal of the RF processing unit 42 of the receiving apparatus is input to the known signal / data signal separation unit 231 of the digital signal processing unit 43. Here, signals of all OAM modes of all UCAs are input to the known signal / data signal separation unit 231, and known signals are different from known signals for channel estimation and synchronization detection for all OAM modes of all UCAs. And control signals etc.

次に、チャネル推定部２３２は、既知信号・データ信号分離部２３１が出力するチャネル推定用既知信号を用いてチャネル推定を行う。チャネル推定処理は、既知信号を用いて、各ＵＣＡの各ＯＡＭモードに対するチャネルに関し、ＺＦやＭＭＳＥ等の手法で行えばよい。チャネル推定部２３２は、このチャネル推定処理結果を干渉除去処理判定部２３３と復調処理部２３４と干渉除去処理部２３５に出力する。   Next, the channel estimation unit 232 performs channel estimation using the channel estimation known signal output from the known signal / data signal separation unit 231. The channel estimation processing may be performed using a known signal, with respect to a channel for each OAM mode of each UCA, by a method such as ZF or MMSE. The channel estimation unit 232 outputs the channel estimation processing result to the interference removal processing determination unit 233, the demodulation processing unit 234, and the interference removal processing unit 235.

干渉除去処理判定部２３３は、各ＵＣＡの各ＯＡＭモード間のチャネル推定結果を用いて、各ＵＣＡと各ＯＡＭモード間の干渉量を計算する。この干渉量は、第１の実施形態のようにチャネル推定計算後の値の絶対値、もしくはその２乗等で計算すればよい。   The interference removal processing determination unit 233 calculates the amount of interference between each UCA and each OAM mode using the channel estimation result between each OAM mode of each UCA. The amount of interference may be calculated as the absolute value of the value after channel estimation calculation or the square of the value as in the first embodiment.

各ＵＣＡの各ＯＡＭモード間の最大干渉信号電力が所定の閾値３より大きいか否かを判定する。また、各ＯＡＭモード間の干渉信号電力が閾値３より大きいＯＡＭモード組の数が所定の閾値４より大きいか否かを判定する。この結果により、第１の実施形態のパターン１−１，１−２，１−３と同様のパターン２−１，２−２，２−３を判定し、判定結果をチャネル推定部２３２と復調処理部２３４と干渉除去処理部２３５に出力する。   It is determined whether the maximum interference signal power between each OAM mode of each UCA is larger than a predetermined threshold 3 or not. In addition, it is determined whether the number of OAM mode sets in which the interference signal power between each OAM mode is larger than the threshold 3 is larger than the predetermined threshold 4 or not. Based on this result, the patterns 2-1, 2-2, 2-3 similar to the patterns 1-1, 1-2, 1-3 of the first embodiment are determined, and the determination result is demodulated with the channel estimation unit 232. It is output to the processing unit 234 and the interference removal processing unit 235.

ここで、チャネル推定部２３２は、パターン２−１と２−２の場合、第１の実施形態のように、復調処理と干渉除去処理に必要なチャネルのみのチャネル推定処理を行うことで、演算量を削減する。また、このようにチャネル推定部２３２が必要なチャネルの推定処理のみを行う場合は、第１の実施形態のように、干渉除去処理判定部２３３は、チャネル推定部２３２が行ったチャネル推定計算結果のみを用いて、パターン２−１，２−２，２−３の判定を行う。   Here, in the case of the patterns 2-1 and 2-2, as in the first embodiment, the channel estimation unit 232 performs calculation by performing channel estimation processing only for channels necessary for demodulation processing and interference removal processing. Reduce the amount. In addition, when the channel estimation unit 232 performs only the necessary channel estimation processing as described above, the interference removal processing determination unit 233 determines the channel estimation calculation result performed by the channel estimation unit 232 as in the first embodiment. The determination of patterns 2-1, 2-2 and 2-3 is performed using

復調処理部２３４は、既知信号・データ信号分離部２３１が出力するデータ信号と、チャネル推定部２３２が出力するチャネル情報を用いて復調処理を行う。すなわち、復調処理部２３４は、干渉除去処理判定部２３３からパターン２−１の結果が入力すると、他のＵＣＡの他のＯＡＭモードからの干渉除去処理を行わずに、各ＵＣＡから同一ＯＡＭモードを用いて送信されたことなる信号間の等化処理を行う。この処理は、ＺＦ等の手法により行えばよい。この処理はＯＡＭモードごとに行う。次に、等化処理後の結果を用いてすべてのデータの復調処理を行う。   The demodulation processing unit 234 performs demodulation processing using the data signal output from the known signal / data signal separation unit 231 and the channel information output from the channel estimation unit 232. That is, when the demodulation processing unit 234 receives the result of the pattern 2-1 from the interference removal processing determination unit 233, the same OAM mode from each UCA is not performed without performing the interference removal processing from the other OAM modes of other UCAs. It performs equalization processing between different signals transmitted using it. This process may be performed by a method such as ZF. This process is performed for each OAM mode. Next, demodulation processing of all data is performed using the result after equalization processing.

また、干渉除去処理判定部２３３からパターン２−２の結果が入力すると、まず、各ＵＣＡの同一ＯＡＭモード間の等化処理と復調処理を行い、その結果を干渉除去処理部２３５に出力する。また、パターン２−２の場合は、第１の実施形態のように、既知信号・データ信号分離部２３１が復調処理部２３４に出力したデータ信号（復調対象のデータ部分の信号）も合わせて干渉除去処理部２３５に出力する。ここで、干渉除去処理部２３５は、ＳＩＣ処理等による干渉除去処理を行い、その結果を再び復調処理部２３４に入力する。復調処理部２３４は、干渉除去処理部２３５から入力する信号を用いて、再び各ＵＣＡの同一ＯＡＭモード間の等化処理と復調処理を行う。この過程を繰り返すことで、干渉除去処理の性能を向上することができる。該繰り返し処理の終了は、第１の実施形態と同様に行えばよい。   Also, when the result of pattern 2-2 is input from the interference removal processing determination unit 233, first, equalization processing and demodulation processing are performed between the same OAM modes of each UCA, and the result is output to the interference removal processing unit 235. Further, in the case of pattern 2-2, as in the first embodiment, the data signal (the signal of the data portion to be demodulated) output to the demodulation processing unit 234 by the known signal / data signal separation unit 231 is also included in the interference. It is output to the removal processing unit 235. Here, the interference removal processing unit 235 performs interference removal processing such as SIC processing, and inputs the result again to the demodulation processing unit 234. The demodulation processing unit 234 performs equalization processing and demodulation processing between the same OAM mode of each UCA again using the signal input from the interference removal processing unit 235. By repeating this process, the performance of the interference removal process can be improved. The termination of the repetitive processing may be performed as in the first embodiment.

また、干渉除去処理判定部２３３からパターン２−３の結果が入力すると、各ＵＣＡの各ＯＡＭモードに対するチャネル情報を用いて、ＺＦやＭＭＳＥ法により等化処理を行い、干渉除去処理を行ってから各ＯＡＭモードの復調処理を行う。   Also, when the result of pattern 2-3 is input from interference removal processing determination section 233, equalization processing is performed by ZF or MMSE using channel information for each OAM mode of each UCA, and interference removal processing is performed. Demodulation processing in each OAM mode is performed.

干渉除去処理部２３５の処理は、第１の実施形態と同様である。本実施形態において、複数のＵＣＡから複数のＯＡＭモードを用いて複数の信号を送受信することは、単一のＵＣＡを用いる第１の実施形態と異なるが、第１の実施形態の復調信号とチャネル情報を用いてレプリカを生成し、受信信号からレプリカを引き算してから、改めて、等化処理と復調処理を行う過程を繰り返すことは同様である。   The processing of the interference removal processing unit 235 is the same as that of the first embodiment. In the present embodiment, transmitting and receiving a plurality of signals from a plurality of UCAs using a plurality of OAM modes is different from the first embodiment using a single UCA, but the demodulated signal and channel of the first embodiment It is the same as repeating the process of performing equalization processing and demodulation processing again after generating a replica using information and subtracting the replica from the received signal.

以下、第２の実施形態の例を数式を用いて説明する。以下の例では、４個のＵＣＡが、それぞれ５個のＯＡＭモード２，１，０，−１，−２を用いてＯＡＭ通信を行う場合を想定する。なお、送信側のＵＣＡをＴx UCA と称し、受信側のＵＣＡをＲx UCA と称する。また、簡単のため図８に示すように、直径が小さいＵＣＡから大きいＵＣＡ順にＵＣＡ１，２，３，４の番号を付ける。すなわち、Ｔx UCA3は、送信側の３番目のＵＣＡを表す。なお、ｋ番目のＵＣＡｋの送信信号をＸi k とし、ｌ番目のＵＣＡｌの受信信号をＹj l とする。ここで、ｉとｊは、ＯＡＭモードの次数を表す。例えば、Ｘ-12 とＹ13は、それぞれ、Ｔx UCA2のＯＡＭモード２の送信信号と、Ｒx UCA3のＯＡＭモード１の受信信号を表す。 Hereinafter, an example of the second embodiment will be described using formulas. In the following example, it is assumed that four UCAs perform OAM communication using five OAM modes 2, 1, 0, -1, -2, respectively. The UCA on the transmission side is referred to as TxUCA, and the UCA on the reception side is referred to as RxUCA. Also, for simplicity, as shown in FIG. 8, UCA 1, 2, 3, 4 are numbered in the order from UCA with smaller diameter to UCA with larger diameter. That is, Tx UCA3 represents the third UCA on the transmitting side. Incidentally, the transmission signal of the k-th UCAk and Xi k, and Yj l received signals l th UCAL. Here, i and j represent the order of the OAM mode. For example, X-1 2 and Y1 3 respectively represent a transmission signal of the OAM Mode 2 Tx UCA2, a reception signal of OAM mode 1 of Rx UCA3.

また、送信ＵＣＡk の送信ＯＡＭモードｉと受信ＵＣＡl のＯＡＭモードｊ間のチャネルをＨi,j l,k と表す。なお、送受信信号は、第１の実施形態のように、ＯＦＤＭ方式等のように周波数領域にてデータ変復調を行う通信方式を想定するが、ＳＣ（single carrier）方式等のように時間領域にてデータを変復調する通信方式への適用も同様に可能である。 Further, the channel between the transmission OAM mode i of the transmission UCAk and the OAM mode j of the reception UCAl is represented as Hi, j1 , k . As in the first embodiment, transmission and reception signals are assumed to be a communication method that performs data modulation and demodulation in the frequency domain as in the OFDM method, but in the time domain as in the SC (single carrier) method and the like. Application to a communication system that modulates and demodulates data is also possible.

本実施形態では、各ＵＣＡの各ＯＡＭモードが異なる信号を送信する通信システムを想定するが、受信電力向上等に向け、ＵＣＡの一部のみを用いて通信を行うことや、ダイバーシティ(diversity) 等の目的に向け各ＵＣＡの同一ＯＡＭモードで同一の信号を送信することも可能である。また、送信側の各ＵＣＡの同一ＯＡＭモードに送信事前処理（プリコーディング）処理を行い、その結果を各ＵＣＡの同一ＯＡＭモードが送信することもできる。すなわち、本実施形態では、送信ＵＣＡの同一ＯＡＭモードは異なる信号を送信し、受信側のＵＣＡのそのＯＡＭモードの信号の等化処理による信号分離を想定するが、送信側がチャネル情報を用いて、事前に等化処理等の事前処理を行う送信することもできる。この場合、受信側の等化処理の必要性がなくなるため、送受信側の信号処理負荷の分担ができる長所がある。   In this embodiment, a communication system is assumed in which each OAM mode of each UCA transmits different signals, but in order to improve reception power etc., communication using only a part of UCA, diversity, etc. It is also possible to transmit the same signal in the same OAM mode of each UCA towards the purpose of Also, the transmission pre-processing (precoding) process may be performed in the same OAM mode of each UCA on the transmission side, and the same OAM mode of each UCA may transmit the result. That is, in this embodiment, the same OAM mode of transmission UCA transmits different signals, and signal separation by equalization processing of the signal of the OAM mode of UCA on the reception side is assumed, but the transmission side uses channel information, It is also possible to transmit in advance pre-processing such as equalization processing. In this case, since there is no need for equalization processing on the reception side, there is an advantage that the signal processing load on the transmission and reception sides can be shared.

受信装置のＲＦ処理部４２の出力信号の式は、以下の式(7) ようになる。本実施形態でも、第１の実施形態のように、チャネル推定用の既知信号とデータ信号を交互に入力する手法や、ＯＦＤＭの複数のキャリアの一部にチャネル推定用の既知信号を挿入し、内挿（interpolation ）等の手法によりチャネル推定を行う手法等が適用できる。   The equation of the output signal of the RF processing unit 42 of the receiving apparatus is given by the following equation (7). Also in this embodiment, as in the first embodiment, a method of alternately inputting a known signal for channel estimation and a data signal, or a known signal for channel estimation is inserted in part of a plurality of OFDM carriers, It is possible to apply a method of channel estimation by a method such as interpolation.

Figure 2019083475
Figure 2019083475

ここで、Ｎj l は、受信側のｌ番目のＵＣＡｌのＯＡＭモードｊの雑音成分を表す。ここで、チャネル推定部は、既知信号を用いてチャネル推定を行う。すなわち、各ＵＣＡの各ＯＡＭモード間のチャネル推定を行い、Ｈi,j l,k 部分を計算する。チャネル推定処理の結果は干渉除去処理判定部に入力される。 Here, Nj l represents the noise component of the OAM mode j of the l-th UCAl on the receiving side. Here, the channel estimation unit performs channel estimation using a known signal. That is, channel estimation is performed between each OAM mode of each UCA, and Hi, j1, k parts are calculated. The result of the channel estimation process is input to the interference removal process determination unit.

干渉除去処理判定部は、すべてのＨi,j l,k の絶対値（もしくは絶対値の２乗）と、所定の閾値３との比較を行い、パターン２−１，２−２，２−３の判定を行う。 The interference removal processing determination unit compares the absolute value (or the square of the absolute value) of all Hi, j l, k with the predetermined threshold value 3 and determines the patterns 2-1, 2-2, and 2-3. Make a decision on

パターン２−１の場合は、各ＵＣＡの異なるＯＡＭモードからの干渉を無視してもよい。すなわち、式(7) を式(8) のように、ＯＡＭモードごとに分離して考えてもよい。   In the case of pattern 2-1, interference from different OAM modes of each UCA may be ignored. That is, equation (7) may be considered separately for each OAM mode as equation (8).

Figure 2019083475
Figure 2019083475

ここで、（Ｎjl)'は、パターン２−１におけるｌ番目の受信ＵＣＡｌのＯＡＭモードｊ
の雑音を表す。このパターンでは、異なるＯＡＭモード間の干渉は無視するため、無視される他のＯＡＭモードからの干渉も雑音成分に含めて表す。次に、受信側の各ＵＣＡの同一ＯＡＭモード間の信号の等化処理を行う。すなわち、式(9) のようにＯＡＭモードごとの等化処理を行う。 Here, (Nj l ) ′ is the OAM mode j of the l-th received UCAl in pattern 2-1.
Represents the noise of In this pattern, since interference between different OAM modes is ignored, interference from other ignored OAM modes is also included in the noise component. Next, equalization processing of signals between the same OAM mode of each UCA on the receiving side is performed. That is, equalization processing for each OAM mode is performed as shown in equation (9).

Figure 2019083475
Figure 2019083475

ここで、Ｅq( )は等化処理を表す。なお、式(9) のＸikは、ｋ番目の送信ＵＣＡｋのＯ
ＡＭモードｉの送信信号の等化処理後の値を表す。なお、Ｘの上につく「＾」や「・」は文中では省略している（以下同様）。この等化処理は、チャネル推定結果と受信ＵＣＡの信号を用いて、ＺＦやＭＭＳＥ等の手法により行えばよい。 Here, Eq () represents equalization processing. In equation (9), Xi k is the O of the k-th transmission UCAk.
This represents the value after equalization processing of the AM mode i transmission signal. In addition, "^" and "." Placed on top of X are omitted in the sentence (the same applies to the following). This equalization process may be performed by a method such as ZF or MMSE using the channel estimation result and the signal of the reception UCA.

次に、等化処理後の結果を用いて復調処理を行う。式(10)のＸikは、ｋ番目の送信ＵＣ
ＡｋのＯＡＭモードｉの送信信号の等化処理後の信号の復調信号を表す。なお、demod( )は、チャネル符号の復号処理等を含む復調処理を表す。 Next, demodulation processing is performed using the result after equalization processing. In equation (10), Xi k is the kth transmission UC
The demodulated signal of the signal after equalization processing of the transmission signal of the OAM mode i of Ak is shown. Note that demod () represents demodulation processing including channel code decoding processing and the like.

Figure 2019083475
Figure 2019083475

パターン２−２の場合は、まず、式(8) のように各ＵＣＡの異なるＯＡＭモードからの干渉を無視してから、式(9) と式(10)のように、各ＵＣＡの同一ＯＡＭモード間の等化処理と復調処理を行い、それらの結果を用いてレプリカを生成し、干渉除去処理の対象となるＯＡＭモード組の干渉除去処理を行う。ここで、干渉除去処理の対象でないＯＡＭモード間の干渉は雑音とみなす。式(7) の受信信号を、各送信ＵＣＡの異なるＯＡＭモードからの干渉成分と同一ＯＡＭモードからの信号に分けると式(11)となる。   In the case of pattern 2-2, first, the interference from different OAM modes of each UCA is ignored as shown in equation (8), and then the same OAM of each UCA is solved as shown in equation (9) and equation (10). Inter-mode equalization processing and demodulation processing are performed, a replica is generated using these results, and interference removal processing of the OAM mode set to be subjected to interference removal processing is performed. Here, interference between OAM modes that are not targets of interference cancellation processing is regarded as noise. If the received signal of equation (7) is divided into interference components from different OAM modes of each transmission UCA and signals from the same OAM mode, equation (11) is obtained.

Figure 2019083475
Figure 2019083475

式(11)には、各ＵＣＡの異なるＯＡＭモードからの信号がすべて表されているが、干渉除去処理判定部により、干渉除去処理対象となる信号のみを残し、式(12)のように、他の干渉除去処理の対象でないＯＡＭモード間の干渉は雑音とみなす。   Although all the signals from different OAM modes of each UCA are represented in the equation (11), the interference removal processing determination unit leaves only the signal to be subjected to the interference removal process as shown in the equation (12). Interference between OAM modes not subject to other interference cancellation processing is regarded as noise.

Figure 2019083475
Figure 2019083475

ここで、第２項のＩは、干渉除去処理判定部により干渉除去対象となるＯＡＭモードの
総数を表し、（Ｎj l)* は、それに含まれてない干渉成分を雑音としてみなした場合の雑
音を表す。本パターンのＳＩＣ処理後の信号は式(13)のように計算する。 Here, I in the second term represents the total number of OAM modes to be subject to interference removal by the interference removal processing determination unit, and (N j l ) * represents noise when the interference component not included therein is regarded as noise Represents The signal after SIC processing of this pattern is calculated as in equation (13).

Figure 2019083475
Figure 2019083475

ここで、Ｙjlは、受信装置のｌ番目のＵＣＡｌのＯＡＭモードｊのＳＩＣ処理後の結果を表す。なお、mod(Ｘik）は、送信側のｋ番目のＵＣＡｋのＯＡＭモードｉの送信信号の
レプリカを表す。mod( ) は、送信装置が行ったチャネル符号化処理を含む変調処理を表す。すなわち、式(13)は、式(10)の復調後の信号と、チャネル推定結果と、ＳＩＣ処理対象をＯＡＭモード組を表すＩを用いて、信号のレプリカを生成し、受信信号がらそのレプリカを引き算する処理を表す。 Here, Yj l represents the results after SIC processing OAM mode j of l-th UCAl of the receiver. Note that mod (Xi k ) represents a replica of the transmission signal of the kth UCAk on the transmission side in the OAM mode i. mod () represents a modulation process including a channel coding process performed by the transmitter. That is, equation (13) generates a replica of the signal using the signal after demodulation of equation (10), the channel estimation result, and I representing the SIC processing target of the OAM mode set, and the received signal replica Represents the process of subtracting

次に、干渉除去処理は、式(13)の計算結果（Ｙ-21 ，Ｙ-11 ，Ｙ01 ，Ｙ11 ，Ｙ21）を
復調処理部に入力する。ここで、ｌは受信ＵＣＡｌの数を意味するため、この例では、20個の計算結果が入力される。 Then, the interference removing process inputs the calculation result of formula (13) and (Y2 1, Y1 1, Y0 1, Y1 1, Y2 1) to the demodulation unit. Here, l means the number of received UCAl, so in this example, 20 calculation results are input.

信号復調部は、式(14)のように等化処理を行う。

Figure 2019083475
The signal demodulation unit performs equalization processing as shown in equation (14).
Figure 2019083475

ここで、式(9) では、Ｙj l を用いて等化処理を行っていたが、式(14)では、ＳＩＣ処理後の結果であるを用いて等化処理を行う。 Here, in the equation (9), the equalization process is performed using Yj l , but in the equation (14), the equalization process is performed using the result after the SIC process.

次に、式(14)の結果を用いて、式(10)で表す復調処理を改めて行う。このパターン２−２では、このような復調処理とレプリカ生成による干渉処理を繰り返して行う。繰り返しの終了は、実施形態１と同様にすればよい。   Next, the demodulation process represented by equation (10) is performed again using the result of equation (14). In this pattern 2-2, such demodulation processing and interference processing by replica generation are repeatedly performed. The end of the repetition may be the same as in the first embodiment.

パターン２−３では、式(7) のすべての項を用いて、ＺＦやＭＭＳＥ等によりすべてのＯＡＭモードの信号に対し、同時に等化処理を行ってから、各ＯＡＭモードの復調処理を行う。   In pattern 2-3, equalization processing is simultaneously performed on signals of all the OAM modes by ZF, MMSE or the like by using all terms of Expression (7), and then demodulation processing of each OAM mode is performed.

このような第２の実施形態は、第１の実施形態と同様の効果がある。すなわち、本発明により、軸ズレやＲＦの不完全性によりＯＡＭモード間の干渉が生じた場合、ＯＡＭモード間の干渉量を考慮して、その処理を要するＯＡＭモード間のみで行うことにより、干渉除去に必要な演算量を削減することができる。また、チャネル推定の演算量の削減も可能となる。特に、ＧＰＳや工学位置調整器なのにより、荒い軸ズレはできたが、精密な軸合わせができなかった場合等、パターン２−２が主となる無線通信環境では、特に演算量の削減効果が大きくなる。また、チャネルの時変動により。パターン２−１，２−２，２−３が時変動する場合、本発明によりチャネル状況に合わせて、適切にＯＡＭモード間干渉除去処理を行うことができるため、常に干渉除去処理をしない手法に比べて、性能改善効果が得られ、また、常にすべてのＯＡＭモードに対する干渉除去処理を行う手法に比べて、演算量削減ができる。   Such a second embodiment has the same effect as the first embodiment. That is, according to the present invention, when interference between OAM modes occurs due to an axial misalignment or RF imperfection, interference is performed only in the OAM modes that require processing, taking into consideration the amount of interference between OAM modes. It is possible to reduce the amount of computation required for removal. In addition, it is possible to reduce the amount of computation of channel estimation. In particular, in a wireless communication environment in which pattern 2-2 is mainly used, such as when a rough axis shift is possible due to GPS or an engineering position adjuster, but precise axis alignment can not be performed, the effect of reducing the amount of computation is particularly effective. growing. Also, due to the time variation of the channel. When the patterns 2-1, 2-2, and 2-3 vary with time, according to the present invention, it is possible to perform inter-OAM mode interference removal processing appropriately according to the channel conditions. Compared with this, the performance improvement effect can be obtained, and the amount of calculation can be reduced as compared with the method in which the interference removal process is always performed for all the OAM modes.

（第３の実施形態）
第３の実施形態は、第１の実施形態および第２の実施形態において、ＯＡＭビームの特性を用いて、干渉除去処理の負荷をさらに軽減する実施形態である。 Third Embodiment
The third embodiment is an embodiment in which the characteristics of the OAM beam are used in the first and second embodiments to further reduce the load of the interference removal process.

干渉除去処理判定部は、符号だけ異なるＯＡＭモードの干渉のパターンは、類似である特徴を用いて、正の符号のＯＡＭモード同士のみで、干渉除去処理の必要性を判断することで、全体の処理量を減らすことができる。例えば、ＯＡＭモード１からＯＡＭモード2 への干渉の度合いと、ＯＡＭモード１からＯＡＭモード２への干渉の度合いは類似であるため、一方のパターンのみの干渉の度合いだけで閾値と比較することで、全体の信号処理負荷をさらに削減する。また、本発明をデジタルチップ等を用いて実装する際にも正の符号のＯＡＭモード間だけの干渉度合いを判定する回路のみを実装することで、全体の回路規模の削減が可能となる。   The interference removal processing determination unit determines the necessity of the interference removal processing only between the OAM modes of the positive code using the feature that is similar to the interference pattern of the OAM mode different only by the code, thereby determining the whole The throughput can be reduced. For example, since the degree of interference from OAM mode 1 to OAM mode 2 and the degree of interference from OAM mode 1 to OAM mode 2 are similar, they are compared with the threshold value based on only the degree of interference of only one pattern. , Further reduce the overall signal processing load. In addition, even when the present invention is implemented using a digital chip or the like, the overall circuit scale can be reduced by implementing only a circuit that determines the degree of interference between the positive code OAM modes.

１１，３１ デジタル信号処理部
１２，３２ ＲＦ処理部
１３，３３ 送信アンテナ部
２１，４１ 受信アンテナ部
２２，４２ ＲＦ処理部
２３，４３ デジタル信号処理部
２３１ 既知信号・データ信号分離部
２３２ チャネル推定部
２３３ 干渉除去処理判定部
２３４ 復調処理部
２３５ 干渉除去処理部
11, 31 digital signal processing unit 12, 32 RF processing unit 13, 33 transmission antenna unit 21, 41 reception antenna unit 22, 42 RF processing unit 23, 43 digital signal processing unit 231 known signal / data signal separation unit 232 channel estimation unit 233 interference removal processing determination unit 234 demodulation processing unit 235 interference removal processing unit

Claims (8)

複数のアンテナ素子を円形に等間隔に配置した等間隔円形アレーアンテナ（以下、ＵＣＡ）を送信装置と受信装置に備え、送信装置のＵＣＡで複数のＯＡＭモードの信号を生成して送信し、受信装置のＵＣＡで複数のＯＡＭモードの信号を受信して分離し、ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信システムにおいて、
前記受信装置は、ＯＡＭモード間のチャネル情報を用いて、所定の閾値１より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う干渉除去手段を備えた
ことを特徴とするＯＡＭ多重通信システム。 A transmitter and a receiver are provided with equally-spaced circular array antennas (hereinafter, UCA) in which a plurality of antenna elements are arranged circularly at equal intervals in a transmitter and a receiver, and UCA of the transmitter generates and transmits a plurality of OAM mode signals In an OAM multiplex communication system in which a plurality of OAM mode signals are received and separated by the UCA of the device, and the number of OAM mode signals are spatially multiplexed and transmitted,
The receiving apparatus includes interference removal means for determining an OAM mode causing interference larger than a predetermined threshold 1 using channel information between the OAM modes, and performing an interference removal process between the OAM modes. OAM multiplex communication system. 請求項１に記載のＯＡＭ多重通信システムにおいて、
前記干渉除去手段は、
前記各ＯＡＭモード間の干渉信号電力を計算し、その最大干渉信号電力が前記所定の閾値１以下の場合は、ＯＡＭモード間の干渉除去処理を行わずに、各ＯＡＭモードの受信信号の復調処理を行う処理手段１と、
前記各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が前記閾値１より大きいＯＡＭモード組数が所定の閾値２以下の場合は、干渉信号電力が閾値１以下のＯＡＭモード間を除くＯＡＭモード間のみの干渉除去処理を行い、各ＯＡＭモードの受信信号の復調処理を行う処理手段２と、
前記各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が前記閾値１より大きいＯＡＭモード組数が前記所定の閾値２より大きい場合は、各ＯＡＭモードのすべての受信信号とすべてのＯＡＭモード間のチャネル情報を用いて干渉除去処理を行い、各ＯＡＭモードの受信信号の復調処理を行う処理手段３と
を備えた構成であることを特徴とするＯＡＭ多重通信システム。 In the OAM multiplex communication system according to claim 1,
The interference removal means is
The interference signal power between each of the OAM modes is calculated, and when the maximum interference signal power is less than or equal to the predetermined threshold 1, the demodulation processing of the received signal of each OAM mode is not performed without performing the interference removal processing between the OAM modes. Processing means 1 for performing
The interference signal power between each of the OAM modes is calculated, and when the number of sets of OAM modes whose interference signal power is greater than the threshold 1 is less than or equal to a predetermined threshold 2, the interval between interference modes where the interference signal power is less than the threshold 1 is excluded Processing means 2 for performing interference removal processing only between the OAM modes and performing demodulation processing of the received signal in each OAM mode;
The interference signal power between each of the OAM modes is calculated, and if the number of OAM mode pairs whose interference signal power is larger than the threshold 1 is larger than the predetermined threshold 2, all received signals and all OAM of each OAM mode are calculated. An OAM multiplex communication system comprising: processing means 3 for performing interference cancellation processing using inter-mode channel information and performing demodulation processing of a received signal in each OAM mode. 請求項１または請求項２に記載のＯＡＭ多重通信システムにおいて、
前記干渉除去手段は、所定の時間間隔ごとにすべてのＯＡＭモード間のチャネル情報を取得し、その区間は、前記所定の閾値１より大きい干渉を及ぼすＯＡＭモード間のみのチャネル情報を取得する構成である
ことを特徴とするＯＡＭ多重通信システム。 In the OAM multiplex communication system according to claim 1 or 2,
The interference removal means acquires channel information between all the OAM modes at predetermined time intervals, and the section acquires channel information only between the OAM modes that exert interference larger than the predetermined threshold 1 An OAM multiplex communication system characterized in that 複数のアンテナ素子を円形に等間隔に配置した等間隔円形アレーアンテナ（以下、ＵＣＡ）を、同心円状に配置した複数のＵＣＡからなるＭ−ＵＣＡを送信装置と受信装置に備え、送信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を生成して送信し、受信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を受信して分離し、ＵＣＡ数×ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信システムにおいて、
前記受信装置は、前記送信装置は各ＵＣＡの各ＯＡＭモード間のチャネル情報を用いて、各ＵＣＡで受信する同一ＯＡＭモード間の信号分離を行うとともに、所定の閾値３より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う干渉除去手段を備えた
ことを特徴とするＯＡＭ多重通信システム。 A transmitter and a receiver are provided with an M-UCA comprised of a plurality of UCAs arranged concentrically, with an equidistant circular array antenna (hereinafter referred to as UCA) in which a plurality of antenna elements are arranged circularly at equal intervals, Each OAM of UCA generates and transmits a plurality of OAM mode signals, each UCA of the receiving apparatus receives and separates each of a plurality of OAM mode signals, and performs space multiplexing transmission of UCA number × OAM mode number signals In a multiplex communication system,
The receiver performs signal separation between the same OAM mode received by each UCA using channel information between each OAM mode of each UCA, and the OAM mode exerts interference larger than a predetermined threshold 3 What is claimed is: 1. An OAM multiplex communication system, comprising: an interference removal unit that determines an interval and performs interference removal processing between the OAM modes. 請求項４に記載のＯＡＭ多重通信システムにおいて、
前記干渉除去手段は、
前記複数のＵＣＡの各ＯＡＭモード間の干渉信号電力を計算し、その最大干渉信号電力が前記所定の閾値３以下の場合は、ＯＡＭモード間の干渉除去処理を行わずに、各ＵＣＡにおける同一ＯＡＭモード間の等化処理による信号分離処理を行い、分離後の各ＯＡＭモードの受信信号の復調処理を行う処理手段１と、
前記複数のＵＣＡの各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が前記閾値３より大きいＯＡＭモード組数が所定の閾値４以下の場合は、干渉信号電力が閾値３以下のＯＡＭモード間を除くＯＡＭモード間のみの干渉除去処理を行い、各ＵＣＡの各ＯＡＭモードの受信信号の復調処理を行う処理手段２と、
前記複数のＵＣＡの各ＯＡＭモード間の干渉信号電力を計算し、その干渉信号電力が前記閾値３より大きいＯＡＭモード組数が所定の閾値４より大きい場合は、各ＵＣＡの各ＯＡＭモードのすべての受信信号と、すべてＵＣＡのＯＡＭモード間のチャネル情報を用いて干渉除去処理を行い、各ＵＣＡの各ＯＡＭモードの受信信号の復調処理を行う処理手段３と
を備えた構成であることを特徴とするＯＡＭ多重通信システム。 In the OAM multiplex communication system according to claim 4,
The interference removal means is
The interference signal power between each OAM mode of the plurality of UCAs is calculated, and when the maximum interference signal power is less than or equal to the predetermined threshold 3, the same OAM in each UCA is not performed without performing the interference cancellation process between the OAM modes. Processing means 1 for performing signal separation processing by equalization processing between modes, and performing demodulation processing of the received signal in each of the separated OAM modes;
The interference signal power between each OAM mode of the plurality of UCAs is calculated, and when the number of OAM mode pairs whose interference signal power is greater than the threshold 3 is less than or equal to a predetermined threshold 4, the OAM of the interference signal power is less than the threshold 3 Processing means 2 for performing interference removal processing only between OAM modes excluding between modes, and performing demodulation processing of a received signal of each OAM mode of each UCA;
If interference signal power between each OAM mode of the plurality of UCAs is calculated, and the number of OAM mode pairs whose interference signal power is larger than the threshold 3 is larger than a predetermined threshold 4, all the OAM modes of each UCA are calculated. And processing means 3 for performing interference cancellation processing using received signal and channel information in all the OAM modes of UCA, and performing demodulation processing of received signals in each OAM mode of each UCA. OAM multiplex communication system. 請求項４または請求項５に記載のＯＡＭ多重通信システムにおいて、
前記干渉除去手段は、所定の時間間隔ごとにすべてのＯＡＭモード間のチャネル情報を取得し、その区間は、前記所定の閾値３より大きい干渉を及ぼすＯＡＭモード間のみのチャネル情報を取得する構成である
ことを特徴とするＯＡＭ多重通信システム。 In the OAM multiplex communication system according to claim 4 or 5,
The interference removal means acquires channel information between all the OAM modes at predetermined time intervals, and the section acquires channel information only between the OAM modes that exert interference larger than the predetermined threshold 3 An OAM multiplex communication system characterized in that 複数のアンテナ素子を円形に等間隔に配置した等間隔円形アレーアンテナ（以下、ＵＣＡ）を送信装置と受信装置に備え、送信装置のＵＣＡで複数のＯＡＭモードの信号を生成して送信し、受信装置のＵＣＡで複数のＯＡＭモードの信号を受信して分離し、ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信方法において、
前記受信装置は、ＯＡＭモード間のチャネル情報を用いて、所定の閾値１より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う
ことを特徴とするＯＡＭ多重通信方法。 A transmitter and a receiver are provided with equally-spaced circular array antennas (hereinafter, UCA) in which a plurality of antenna elements are arranged circularly at equal intervals in a transmitter and a receiver, and UCA of the transmitter generates and transmits a plurality of OAM mode signals In an OAM multiplex communication method in which a plurality of OAM mode signals are received and separated by the UCA of the device, and the number of OAM mode signals are spatially multiplexed and transmitted,
The receiving apparatus determines between OAM modes that cause interference larger than a predetermined threshold value 1 by using channel information between OAM modes, and performs interference cancellation processing between the OAM modes. . 複数のアンテナ素子を円形に等間隔に配置した等間隔円形アレーアンテナ（以下、ＵＣＡ）を、同心円状に配置した複数のＵＣＡからなるＭ−ＵＣＡを送信装置と受信装置に備え、送信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を生成して送信し、受信装置の各ＵＣＡでそれぞれ複数のＯＡＭモードの信号を受信して分離し、ＵＣＡ数×ＯＡＭモード数の信号を空間多重伝送するＯＡＭ多重通信方法において、
前記受信装置は、前記送信装置は各ＵＣＡの各ＯＡＭモード間のチャネル情報を用いて、各ＵＣＡで受信する同一ＯＡＭモード間の信号分離を行うとともに、所定の閾値３より大きい干渉を及ぼすＯＡＭモード間を判定し、そのＯＡＭモード間の干渉除去処理を行う ことを特徴とするＯＡＭ多重通信方法。
A transmitter and a receiver are provided with an M-UCA comprised of a plurality of UCAs arranged concentrically, with an equidistant circular array antenna (hereinafter referred to as UCA) in which a plurality of antenna elements are arranged circularly at equal intervals, Each OAM of UCA generates and transmits a plurality of OAM mode signals, each UCA of the receiving apparatus receives and separates each of a plurality of OAM mode signals, and performs space multiplexing transmission of UCA number × OAM mode number signals In the multiplex communication method,
The receiver performs signal separation between the same OAM mode received by each UCA using channel information between each OAM mode of each UCA, and the OAM mode exerts interference larger than a predetermined threshold 3 An OAM multiplex communication method comprising: determining an interval between them and performing interference cancellation processing between the OAM modes.
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