JPWO2009078472A1 - COMMUNICATION METHOD, SYSTEM, AND COMMUNICATION DEVICE - Google Patents

Abstract

It is to reduce communication hindrance associated with spatial multiplexing. A spatial multiplexing communication method can be obtained in which priorities are assigned to a plurality of spatial streams based on propagation path prediction, and data with high priority is assigned to spatial streams with high priority. By adopting such a configuration, it is possible to effectively utilize communication resources in the reverse direction without hindering communication by reducing the frequency of communication in the reverse direction to follow the time change of the propagation path characteristics, and communication hindrance occurs. The object of making it difficult to cause delay due to retransmission control is achieved.

Description

  The present invention relates to a spatial multiplexing communication method, system, and communication apparatus such as a transceiver.

特異値分解などを用いて、相関行列Ｈ^ＨＨとＨＨ^Ｈの共通の固有値λｉ（ｉ＝１，２，…ｍ）を求める。
｛・｝^Ｈは行列の複素共役転置を表す。
相関行列Ｈ^ＨＨの固有値λｉに対する固有ベクトルｅ_ｔ，ｉ、相関行列ＨＨ^Ｈの固有値λｉに対する固有ベクトルｅ_ｒ，ｉを用いて、送信側ウェイトＥ_ｔ（７０２）及び受信側ウェイトＥ_ｒ ^Ｈ（７０６）を以下に設定する事で固有値伝送を行う。

固有値、固有ベクトルの求め方には、特異値分解の他に、ラグランジュ法、ＱＲ分解、シュール分解、Ｈｏｕｓｅｈｏｌｄｅｒ法、ＢＤ法など多くの方法が提案されている（非特許文献５参照）。
このとき、第ｉ空間ストリームに割り付ける信号Ｓｉにより構成するＳ（７０３）と、送信アンテナ（または偏波）ｊで伝送する信号ｘｊの関係は以下になる。

ここで、ｙｔ，ｉ，ｊ（ｉ＝１，２，…，ｍ，ｊ＝１，２，…Ｍ）は空間ストリームλｉの固有ベクトルｅ_ｔ，ｉの要素であり、αｉは各空間ストリームの電力制御に用いるゲインである。
αｉは、各空間ストリームの固有値と受信側の雑音情報と空間ストリームの総電力にから、注水定理により決定する。これにより、第ｉ空間ストリームの信号対雑音比ＳＮＲｉが決定すると、通信容量の上限Ｃｉを決定できる（特許文献３参照）。

このとき、Ｗは通信帯域、σ^２は受信側の雑音、Ｐｉは送信側で設定する電力である。

実際のシステムの例では、受信側の移動局が伝搬路情報によって、システムで用意される離散的な値の中から電力及びデータレートを指定する。伝搬路情報の従来例としては単位ブロック当たりのデータ量を選択するＣＱＩ（Ｃｈａｎｎｅｌ Ｑｕａｌｉｔｙ Ｉｎｄｉｃａｔｏｒ）、ウェイトを通知するＰＣＩ（Ｐｒｅｃｏｄｉｎｇ ｃｏｎｔｒｏｌ ｉｎｄｉｃａｔｏｒ）やＣｏｄｅｂｏｏｋ Ｉｎｄｅｘがあり、ウェイト更新間隔Ｐｒｅｃｏｄｉｎｇ ｕｐｄａｔｅ Ｉｎｔｅｒｖａｌについても検討されている（非特許文献１０、非特許文献１１、非特許文献１２参照）。
その後に、スケジューラがデータレートに合わせてデータを割り付ける。
受信信号Ｒ（７０７）は、以下のように与えられる。

Ｗ−ＳＤＭでは、伝搬路特性に基づいて送信側では送信電力制御及び伝送レート制御のみを行う。従って、空間ストリーム数ｍ＝Ｍであり、αｉを空間ストリーム毎に制御するのみである。

受信側では、いくつかの方法があり、例えばＺＦ（Ｚｅｒｏ ｆｏｒｃｉｎｇ）とＭＭＳＥ（Ｍｉｎｉｍｕｍ Ｍｅａｎ Ｓｑｕａｒｅ Ｅｒｒｏｒ）がある。
ＺＦの受信ウェイトをＷ_ｒ＿ＺＦ、ＭＭＳＥの送信ウェイトをＷ_{ｒ＿ＭＭＳＥ}とすると、以下のようである。

ここでσ^２は受信側雑音、Ｉは単位行列である。
送信する情報を各空間ストリームで送信可能なデータレートに分配して送信する事で、無線リソースを有効活用して伝送できる（非特許文献７、非特許文献８参照）。
また、周波数分割複信方式（ＦＤＤ）においては、上りと下りで周波数が異なる為、伝搬路特性も異なる。従って、下りで固有値伝送を行う場合は上りから下りに、上りで固有値伝送を行う場合は下りから上りにＥ_ｔを通知する必要がある（特許文献１参照）。
この通知する信号を削減するためのコードブックという符号化方法がある（非特許文献３参照）。
時分割複信方式（ＴＤＤ）においては、ＦＤＤと同じ方法を用いる場合もあるが、上りと下りの伝搬路特性が等しい為、送信側で伝搬路特性を計算できる。この場合は、伝搬路計算を行う元になる信号を受信側から送信側に送信する必要がある。送信信号は、プリアンブルやサウンディングという既知信号の送信を行う方法が一般的であるが、先に述べる再送制御において、ＡＣＫ、ＮＡＣＫなどの制御信号を代わりに用いた無線リソース削減方法も提案されている（非特許文献７参照）。
送信側で符号化し、受信側で復号する事により復号データ誤りを含むかどうかを判定出来る。そして、受信側から送信側に受信データが誤りを含むかどうかをＡＣＫ、ＮＡＣＫ信号で通知し、再送制御を行う方法がある（特許文献１参照）。
また、送信ウェイト更新を頻繁に行わない時、最大固有値の空間ストリームは劣化しやすい事が報告されている（非特許文献４参照）。
関連する技術として、伝搬路の変動を予測するチャネル行列変動予測と（特許文献４参照）、送信順序を受信側から送信側に指定するオーダリング（特許文献５参照）、データの優先度に応じた適応変調を行う優先度制御（特許文献６参照）がある。
特開２００７−１６６６３３号公報 （［００１７］−［００２１］、図１） 特表２００５−５０２２２３号公報 （［００７９］−［００９６］、図１、図５） 特開２００５−２５２８３４号公報 （［００１８］−［００２２］） 特開２００６−３０３６２５号公報 （［００４４］、図１） 特開２００６−１３６８０号公報 （［００２４］−［００２９］、図４、図５） 特開２００６−３３３２８３号公報 （［００３３］−［００３７］、図１、表２） 高村 誠之，八島 由幸，「Ｈ．２６４に基づくスケーラブル動画像可逆符号化」信学会Ｄ誌、２００６年２月、Ｖｏｌ．Ｊ８９−Ｄ Ｎｏ．２ ｐｐ．３１４−３２２ 金 弘林，藤吉 正明，関 裕介，貴家 仁志，「法演算を用いるＪＰＥＧ２０００符号化画像への情報埋込法」 信学会Ａ誌、２００６年３月、Ｖｏｌ．Ｊ８９−Ａ Ｎｏ．３ ｐｐ．２３４−２４２（ＲＯＩ） ３ＧＰＰ，ＴＳ ３６．２１１ ｖ．８．０，（６．３．４．２．３．Ｃｏｄｅｂｏｏｋ ｆｏｒ ｐｒｅｃｏｄｉｎｇ，ｐ．２９）２００７年９月 森，田邊，佐藤，“ＳＶＤ−ＭＩＭＯシステムにおける伝搬路時間変動にロバストなリンクアダプテーション方式”，Ｂ−５−３９，ソ大論文，２００７年９月 Ｙ．Ｋａｒａｓａｗａ，″Ｉｎｎｏｖａｔｉｖｅ Ａｎｔｅｎｎａｓ ａｎｄ Ｐｒｏｐａｇａｔｉｏｎ Ｓｔｕｄｉｅｓ ｆｏｒ ＭＩＭＯ Ｓｙｓｔｅｍｓ，″ＩＥＩＣＥ Ｔｒａｎｓ．Ｃｏｍｍｕｎｓ．，Ｓｐｅｃｉａｌ Ｓｅｃｔｉｏｎ：２００６ Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｓｙｍｐｏｓｉｕｍ ｏｎ Ａｎｔｅｎｎａｓ ａｎｄ Ｐｒｏｐａｇａｔｉｏｎ（ＩＳＡＰ２００６），ｖｏｌ．Ｅ９０−Ｂ，ｎｏ．９，ｐｐ．２１９４−２２０２，２００７年３月 ２．１章 三上学，藤井輝也，“フィードバック遅延およびアンテナ相関の影響を考慮したＭＩＭＯ伝送方式の性能評価”，Ｂ−５−８０，信学総合大会，２００５年３月（図２） 堤貴彦，西村寿彦，大鐘武雄，“各種空間多重方式におけるチャネル情報誤差の影響に関する検討”，Ｖｏｌ．Ｊ８９−Ｂ Ｎｏ．９，ｐｐ．１４９６−１５０４，電子通信学会論文誌Ｂ，２００４年９月 衣斐信介，三瓶政一，森永 規彦，“伝送容量制御型ＭＩＭＯ適応変調方式”，Ｖｏｌ．Ｊ８８−Ｂ Ｎｏ．６ ｐｐ．１０９０−１１０１，電子通信学会論文誌Ｂ，２００５年６月 ｐｐ．１０９２−１０９３，式（９） 水谷慶，坂口啓，高田潤一，荒木純道，“リアルタイム伝搬測定にもとづくＭＩＭＯ固有モード間相関解析”，Ｂ−１−２４７，信学ソサイエティ大会，２００５年９月 （式（２）、式（３）） ３ＧＰＰ，ＴＳ ２５．２１４ ｖ．７．６，（９．ｐ．７１−７２，ＭＩＭＯブロック図，６．Ａ．２．２−６．ａ．４，ｐ．４４−５５ ＨＡＲＱ，ＰＣＩ）２００７年９月 ３ＧＰＰ，Ｒ１−０７２８４３”Ｗａｙ Ｆｏｒｗａｒｄ ｏｎ ４−Ｔｘ Ａｎｔｅｎｎａ Ｃｏｄｅｂｏｏｋ ｆｏｒ ＳＵ−ＭＩＭＯ“２００７年６月 ３ＧＰＰ，Ｒ１−０７００９３“Ｉｎｖｅｓｔｉｇａｔｉｏｎｓ ｏｎ Ｃｏｄｅｂｏｏｋ Ｓｉｚｅ ｆｏｒ ＭＩＭＯ Ｐｒｅｃｏｄｉｎｇ ｉｎ Ｅ−ＵＴＲＡ Ｄｏｗｎｌｉｎｋ”２００７年１月 Ｆｉｇｕｒｅｌ 守倉正博，久保田周治，“８０２．１１高速無線ＬＡＮ教科書”，２００４年１２月，インプレス This type of spatial multiplexing communication is used to send and receive multimedia information such as video information and audio information. Priorities can be set for such multimedia information according to importance. For example, when audio and image are transmitted simultaneously as video information, the audio information has a higher priority than the image information. Further, scalable coding generates a plurality of pieces of information with different quantization roughnesses from the same multimedia information, thereby generating information with different priorities. Furthermore, image coding has a concept of a range of high priority called a region of interest (ROI). Increasing the resolution increases the amount of data, but increasing the resolution of only important parts such as the boundaries of characters and characters is an effective means of increasing the resolution without increasing the amount of data (Non-Patent Document 1, Non-Patent Document 1). 2). Thus, multimedia information has a priority according to the characteristics of the information (see Non-Patent Document 12). For example, a priority that does not guarantee the quality of data is called background, best effort, and a priority that guarantees the quality of data is called guarantee, and the priority is further defined by data (see Non-Patent Document 13).
Scalability includes SNR scalability, spatial scalability, temporal scalability, and ROI scalability.
Scalability coding can generate a small amount of data with low quality from the same information source and can also generate data with high quality.
This enables a plurality of types of communication with different quality in the same data distribution in broadcast communication.
Specifically, JPEG2000, H.264. There are many standard systems such as 264, MPEG4, MPEG4 AAC. As an example, when described using spatial scalability, scalable coding transmits a base layer with the lowest resolution and a data string of an enhancement layer for increasing the resolution together with the base layer.
On the receiving side, reception is selectively performed according to the processing capability of each device. A portable terminal with a low resolution receives only the base layer and discards other information without receiving it. A device having a large display unit increases the resolution by receiving all the data strings of the enhancement layer in addition to the base layer. (Refer nonpatent literature 1 and nonpatent literature 2.).
On the other hand, in personal communication in which communication is performed between one or more specific transceivers, spatial multiplex communication (MIMO: Multi Input Multi Output) is performed. In addition to SDM (Space Division Multiplexing) in which propagation path calculation is performed on the receiving side, MIMO includes E-SDM (Eigenbeam-Space) in which weights calculated from propagation path characteristics between transmitters and receivers are multiplied on the transmission side for speeding up. There are Division Multiplexing (W) and W-SDM (Weighted-Space Division Multiplexing) (see Patent Document 2).
As an example, FIG. 11 shows E-SDM, which is a spatial multiplexing method using eigenvalues.
The maximum value of the number m of spatially multiplexed streams in the propagation path constituted by M transmission antennas 703 and N reception antennas 705 is given by m ≦ min (M, N). min (M, N) is a smaller value of either M or N. When cross-correlation of propagation path characteristics does not become a problem, m = min (M, N) is obtained, and when it becomes a problem, the number of eigenvalues decreases and m <min (M, N).
In the frequency division duplex method (FDD method), the uplink and downlink frequencies are different, so the propagation path characteristics are different. Therefore, on the receiving side, a known signal (or a pseudo known signal) sent from the transmitting side to the receiving side is used. When a correctly received signal that can be handled) is received, the reception side multiplies the complex conjugate of the known signal and averages it to eliminate the influence of noise to calculate the propagation path characteristics. As a result, a propagation path calculation value hkj (k = 1, 2,... N, j = 1, 2,... M) between the transmitting antenna j and the receiving antenna k is obtained.
The known signal is a signal for determining the propagation path for each antenna, and is different for each antenna when transmitting at the same time. However, the same signal may be used when specifying time such as uplink sounding. A propagation path matrix H (704) is obtained using this propagation path calculation value.

A common eigenvalue λi (i = 1, 2,..., ^M) of correlation matrices H ^H H and HH ^H is obtained by using singular value decomposition or the like.
{·} ^H represents a complex conjugate transpose of a matrix.
Eigenvector _{e t} for the eigenvalues λi of the correlation matrix ^{H H} _{H, i,} eigenvector _{e r} for the eigenvalues λi of the correlation matrix HH _^H, with _i, sender weight _E t (702) and the receiving weights _E ^r H (706) Set the following to perform eigenvalue transmission.

In addition to singular value decomposition, many methods such as Lagrangian method, QR decomposition, surreal decomposition, Householder method, and BD method have been proposed for obtaining eigenvalues and eigenvectors (see Non-Patent Document 5).
At this time, the relationship between S (703) configured by the signal Si assigned to the i-th spatial stream and the signal xj transmitted by the transmission antenna (or polarization) j is as follows.

Here, yt, i, j (i = 1, 2,..., M, j = 1, 2,... M) are elements of the eigenvectors et _{, i} of the spatial stream λi, and αi is the power of each spatial stream. This is the gain used for control.
αi is determined by the water injection theorem from the eigenvalue of each spatial stream, the noise information on the receiving side, and the total power of the spatial stream. Thus, when the signal-to-noise ratio SNRi of the i-th spatial stream is determined, the upper limit Ci of the communication capacity can be determined (see Patent Document 3).

At this time, W is a communication band, σ ² is noise on the receiving side, and Pi is power set on the transmitting side.

In an actual system example, the mobile station on the receiving side designates the power and data rate from the discrete values prepared by the system based on the propagation path information. Conventional examples of channel information include CQI (Channel Quality Indicator) for selecting the amount of data per unit block, PCI (Precoding Control Indicator) for notifying the weight, and Codebook Index, and the weight update interval Precoding update is also considered. (See Non-Patent Document 10, Non-Patent Document 11, Non-Patent Document 12).
Thereafter, the scheduler allocates data according to the data rate.
Received signal R (707) is given as follows.

In W-SDM, only transmission power control and transmission rate control are performed on the transmission side based on propagation path characteristics. Therefore, the number of spatial streams m = M, and αi is only controlled for each spatial stream.

On the receiving side, there are several methods, for example, ZF (Zero Forcing) and MMSE (Minimum Mean Square Error).
_Assuming that the reception weight of ZF is W _{r_ZF} and the transmission weight of MMSE is W _{r_MMSE} , it is as follows.

Here, σ ² is reception side noise, and I is a unit matrix.
By distributing and transmitting the information to be transmitted to the data rate that can be transmitted in each spatial stream, it is possible to transmit the radio resource effectively (see Non-Patent Document 7 and Non-Patent Document 8).
In addition, in frequency division duplex (FDD), the frequency characteristics are different between upstream and downstream, so that the propagation path characteristics are also different. Therefore, the downlink from the uplink when performing eigenvalue transmitted in downlink, when performing eigenvalue transmitted uplink needs to notify the E _t in the uplink from the downlink (see Patent Document 1).
There is an encoding method called a code book for reducing the signal to be notified (see Non-Patent Document 3).
In the time division duplex (TDD) method, the same method as FDD may be used, but since the uplink and downlink channel characteristics are equal, the channel characteristics can be calculated on the transmission side. In this case, it is necessary to transmit a signal from which the propagation path calculation is performed from the reception side to the transmission side. As a transmission signal, a method of transmitting a known signal such as a preamble or sounding is generally used, but a radio resource reduction method using a control signal such as ACK or NACK instead in the retransmission control described above has been proposed. (Refer nonpatent literature 7).
It is possible to determine whether or not a decoded data error is included by encoding on the transmission side and decoding on the reception side. There is a method of performing retransmission control by notifying whether or not received data includes an error from the receiving side to the transmitting side using an ACK or NACK signal (see Patent Document 1).
Further, it has been reported that when the transmission weight is not frequently updated, the spatial stream having the maximum eigenvalue is likely to deteriorate (see Non-Patent Document 4).
As related technologies, channel matrix fluctuation prediction for predicting propagation path changes (see Patent Document 4), ordering for specifying the transmission order from the reception side to the transmission side (see Patent Document 5), and the priority of data There is priority control for performing adaptive modulation (see Patent Document 6).
JP 2007-166633 A ([0017]-[0021], FIG. 1) JP-T-2005-502223 ([0079]-[0096], FIG. 1, FIG. 5) JP 2005-252834 A ([0018]-[0022]) JP 2006-303625 A ([0044], FIG. 1) JP 2006-13680 A ([0024]-[0029], FIG. 4, FIG. 5) JP 2006-333283 A ([0033]-[0037], FIG. 1, Table 2) Nobuyuki Takamura, Yoshiyuki Yashima, “Reversible Encoding of Scalable Video Based on H.264”, IEICE Journal, February 2006, Vol. J89-D No. 2 pp. 314-322 Kim Kobayashi, Masaaki Fujiyoshi, Yusuke Seki, Hitoshi Takaya, “Information Embedding Method in JPEG2000 Coded Images Using Legal Operations”, Journal of Academic Society of Japan, March 2006, Vol. J89-A No. 3 pp. 234-242 (ROI) 3GPP, TS 36.211 v. 8.0, (6.3.4.2.2.3. Codebook for precoding, p. 29) September 2007 Mori, Tanabe, Sato, “Link adaptation method robust to channel time fluctuation in SVD-MIMO system”, B-5-39, Sodai paper, September 2007 Y. Karasawa, “Innovative Antennas and Propagation Studies for MIMO Systems,” IEICE Trans. Communs. , Special Section: 2006 International Symposium on Antennas and Propagation (ISAP 2006), vol. E90-B, no. 9, pp. 2194-2202 March 2007 Chapter 2.1 Manabu Mikami, Teruya Fujii, “Performance Evaluation of MIMO Transmission Systems Considering Effects of Feedback Delay and Antenna Correlation”, B-5-80, IEICE General Conference, March 2005 (Figure 2) Takahiko Tsutsumi, Toshihiko Nishimura, Takeo Ogane, “Study on the effect of channel information error in various spatial multiplexing systems”, Vol. J89-B No. 9, pp. 1496-1504, IEICE Transactions B, September 2004 Shinsuke Kinu, Seiichi Sampei, Norihiko Morinaga, “Transmission Capacity Control MIMO Adaptive Modulation”, Vol. J88-B No. 6 pp. 1090-1101, IEICE Transactions B, June 2005 pp. 1092-1093, Formula (9) Kei Mizutani, Kei Sakaguchi, Junichi Takada, Junmichi Araki, “Correlation Analysis between MIMO Eigenmodes Based on Real-Time Propagation Measurements”, B-247, Science Society Conference, September 2005 (Formula (2), Formula ( 3)) 3GPP, TS 25.214 v. 7.6, (9.p.71-72, MIMO block diagram, 6.A.2.2-6.a.4, p.44-55 HARQ, PCI) September 2007 3GPP, R1-072843 "Way Forward on 4-Tx Antenna Codebook for SU-MIMO" June 2007 3GPP, R1-070093 “Investigations on Codebook Size for MIMO Precoding in E-UTRA Downlink” January 2007, Figure Masahiro Morikura, Shuji Kubota, “802.11 High-Speed Wireless LAN Textbook”, December 2004, Impress

However, all the methods described in Patent Documents 1 to 6 and Non-Patent Documents 1 to 13 have the following problems. The first problem is that resources are wasted because communication in the reverse direction is frequently performed in order to follow changes in propagation path characteristics.
More specifically, in frequency duplex (FDD), propagation path information obtained by encoding propagation path characteristics calculated on the reception side is notified to the transmission side. In the time division duplex (TDD) method, the same method as FDD is adopted. Alternatively, in order to calculate the propagation path characteristic on the transmission side, it is sent from the reception side to the transmission side. A method in which a known signal or a signal in place of the known signal is transmitted may be employed.
The second problem is a delay caused by retransmission control.
The reason is that if an error occurs during communication, it takes time to make a retransmission request from the reception side to the transmission side, retransmit from the transmission side, and receive again (refer to Non-Patent Document 6 for retransmission control).
A third problem is that in E-SDM, calculation for weight update is frequently performed. The reason is that, in order to follow the change of the propagation path characteristic, the acquisition of the propagation path characteristic and the weight calculation based on it are frequently performed.
Due to such a problem, in the conventional communication method, there is a case where multimedia communication is stopped, for example, communication hindrance such as video stop occurs.

Further, Patent Documents 4 and 6 only disclose that a transmission method according to the priority of transmission data is selected based on propagation path prediction.
In the present invention, by clearly associating degradation predictions of a plurality of spatial streams and priority of transmission data, communication of data with priority is not inhibited, radio resources are effectively used, and delay due to retransmission control is reduced. The transmission weight calculation frequency can be reduced.
Specifically, the principle of the present invention is to assign priority to a spatial stream based on spatial degradation prediction (propagation channel prediction) to a plurality of spatial streams, and to consider transmission data in consideration of the priority of the spatial stream. Is to reduce the adverse effects of retransmission control and the like.
That is, according to the present invention, it is possible to obtain a communication method in which priorities are assigned to a plurality of multiplexed streams based on propagation path prediction, and data with high priority is assigned to the multiplexed streams with high priority. Specifically, the spatial multiplexing communication method for prioritized data between specific transceivers according to the present invention includes a priority allocation unit, a spatial multiplexing transmission unit, a spatial multiplexing reception unit, a priority decoding unit, and propagation. A path estimation means and a propagation path prediction priority determination means, which operate so as to assign high priority data with high priority to a spatial stream that is not easily degraded.
Adopting such a configuration, in the case of data communication with priority, by reducing the communication frequency in the reverse direction to follow the time variation of the propagation path characteristics, communication resources in the reverse direction can be saved without hindering communication. When using a method that requires effective weight calculation for tracking the propagation path characteristics on the transmitting side, such as E-SDM, the number of weight calculation processes for tracking the propagation path characteristics can be reduced, and communication obstruction can be prevented. Occurrence can be reduced and delay due to retransmission control can be reduced.

According to the present invention, it is possible to effectively utilize radio resources from the reception side to the transmission side without hindering communication of data with priority. The reason for this is that even if the quality of the spatial stream is predicted to change over time, the priority is set to the spatial stream, and data with priority is assigned according to the priority of the spatial stream. This is because communication of data with priority is not hindered.
Furthermore, according to the present invention, the E-SDM can reduce the transmission weight calculation frequency without stopping communication of data with priority. The reason is that even if the transmission frequency calculation frequency for following the time variation of the propagation path characteristics is reduced, the priority-added data with high priority can be communicated without error and communication is not hindered.

FIG. 1 is a block diagram for explaining a communication system according to the first embodiment of the present invention.
FIG. 2 is a flowchart for schematically explaining the operation of the communication system according to the present invention.
FIG. 3 is a block diagram illustrating a communication system according to the second embodiment of the present invention.
FIG. 4 is a flowchart for specifically explaining the operation of the communication system according to the first embodiment.
FIG. 5 is a flowchart showing the operation of the best mode for carrying out the first invention.
FIG. 6 is a flowchart showing the operation of the best mode for carrying out the first invention.
7A to 7E are block diagrams showing a configuration for explaining another embodiment of the present invention.
8A to 8E are block diagrams showing a configuration for explaining another embodiment of the present invention.
9A to 9D are block diagrams showing a configuration for explaining another embodiment of the present invention.
10A and 10B are schematic views showing a configuration for explaining another embodiment of the present invention.
FIG. 11 is a schematic diagram for explaining a conventional example.
12A and 12B are block diagrams illustrating the third embodiment of the present invention.
FIG. 13 is a flowchart for explaining the operation of the system according to the third embodiment.

特異値分解などを用いて、相関行列Ｈ^ＨＨとＨＨ^Ｈの共通の固有値λｉ（ｉ＝１，２，…ｍ）を求める。
｛・｝^Ｈは行列の複素共役転置を表す。
相関行列Ｈ^ＨＨの固有値λｉに対する固有ベクトルｅ_ｔ，ｉ、相関行列ＨＨ^Ｈの固有値λｉに対する固有ベクトルｅ_ｒ，ｉを用いて、送信側ウェイトＥ_ｔ及び受信側ウェイトＥ_ｒ ^Ｈを以下に設定する事で固有値伝送を行う。

このとき、第ｉ空間ストリームに割り付ける情報Ｓｉと、送信アンテナ（または偏波）ｊで伝送する信号ｘｊの関係は以下になる。

ここで、ｙｔ，ｉ，ｊ（ｉ＝１，２，…，ｍ，ｊ＝１，２，…Ｍ）は空間ストリームλｉの固有ベクトルｅ_ｔ，ｉの要素であり、αｉは各空間ストリームの電力制御に用いるゲインである。
Ｗ−ＳＤＭは、伝搬路特性に基づいて送信側で送信電力制御及び伝送レート制御のみを行う。従って、空間ストリーム数ｍ＝Ｍであり、αｉを空間ストリーム毎に制御するのみである。
Ｘ＝Ｓ 式２７

伝搬路１０７は空間多重伝搬路である。
伝搬路推定部１０６は、既知信号もしくは、判定済み信号を疑似的に既知信号として用いて、その既知信号の複素共役を乗算して平均化する事により、各々の送受信アンテナ（もしくは偏波）間における空間多重伝搬路の特性を計算し、伝搬路計算値を出力する。
即ち、伝搬路推定部１０６では、伝搬路を通った信号に既知信号もしくは疑似既知信号の複素共役を乗算し、雑音の影響を除くために平均化して伝搬路特性を計算する動作が行われる。結果として、送信アンテナｊと受信アンテナｋ間の伝搬路計算値ｈｋｊ（ｋ＝１，２，…Ｎ，ｊ＝１，２，…Ｍ）を得る。この伝搬路計算値を用いて伝搬路行列Ｈを得る。
次に、伝搬路予測優先度設定部１０５は、伝搬路計算値から各空間ストリームの劣化し易さを予測し、劣化しにくいものに高く、劣化しやすいものに低い優先度を空間ストリームの優先度として割り付ける。
図２のフローチャートに基づいて、伝搬路予測優先度設定部１０５における劣化予測方法について説明すると、伝搬路計算値が入力されると（ステップａ１）、空間ストリームの劣化しやすさの指標を計算し（ステップａ２）、劣化しやすさに基づいて各空間ストリームの優先度を設定する（ステップａ３）。
上記した伝搬路推定部１０６、伝搬路予測優先度設定部１０５、及び、優先度割付部１０１の動作は、ハードウェア回路によって実現できるだけでなく、ソフトウェアによっても実現できる。このことは、以下に説明する他の実施形態においても同様である。
空間多重受信部１０３は、複数アンテナ素子もしくは単一アンテナ素子の偏波を用いて受信し、信号処理によって空間多重送信された信号を分離する。優先度付き復号部１０４は、優先度付き符号化信号を復号する。
優先度付き復号は、伝搬路特性の変化によって優先度の高い情報が誤る場合は通信阻害となるが、優先度の低い情報が誤っていても優先度の高い情報が正しく伝搬されると品質劣化となるだけで通信成功となる。
従って、本発明に係る方式は、優先度割付により、伝搬路特性の追従性低下による誤りを、優先度付きデータの優先度の低い部位に偏らせる事ができる。この結果、優先度の低い情報が誤っていても、通信は阻害されることがなく、また、伝搬路特性の送信ウェイトに対する反映頻度を減らすことが可能になる。
次に、本発明の第２の発明を実施するための最良の形態について図面を参照して詳細に説明する。
本発明の第２の実施の形態は、特定の一つ又は複数の送受信機間における優先度付きデータ通信に関するものであり、図３を参照すると、本発明の第２の実施の形態の動作は、優先度付きデータは、各々関連する異なる優先度の複数のデータ列で構成される情報である。
データ列に付けられる優先度は、この実施形態においても、データ列の重要度に応じて付けられる。例えば、音声情報と画像情報の混在するビデオ情報においては、音声情報は画像情報より優先度が高く、また、スケーラブル符号化データでは、基本レイヤと呼ばれる最も品質が低く量の小さいデータの優先度は、品質を上げる為の拡張レイヤより優先度が高い。
優先度付きデータは、優先度割付部２０１において、優先度の高いデータ列から順次、優先度の高い空間ストリームに割り付けられる。
各空間ストリームに割り付けられた優先度付きデータは、多重送信部２０２において、多重送信される。多重方法は、空間多重、周波数多重、時間多重がある。
伝搬路推定部２０６は、既知信号もしくは、判定済み信号を疑似的に既知信号として用いて、伝搬路を通った信号に既知信号の複素共役を乗算して平均化する事により、各々の伝搬路の特性を計算し、伝搬路計算値を出力する。
この実施形態では、伝搬路計算値は伝搬路予測優先度設定部２０５に通知され、多重送信部２０２には通知されていない点で、図１とは相違している。
伝搬路予測優先度設定部２０５は、通知される伝搬路特性から各空間ストリームの劣化し易さを予測し、劣化しにくいものに高く、劣化しやすいものに低い優先度を割り付け、各空間ストリームの優先度を出力する。
ここで言う伝搬路特性とは、信号対雑音比などであり、１度の計算から予測する場合は、値が比較値と比べて低いなどである。
また、繰り返し通信中においては、今回と前回の伝搬路計算値の変化から、各空間ストリームの安定性を判断して、安定した空間ストリームにはそうでない空間ストリームより高い優先度を設定するなどである。
通信中においてパケットを繰り返し送受信する状態では、伝搬路計算値を繰り返し計算して空間ストリームの優先度を設定し直す。
図２に示されたフローチャートを再度参照して、図３に示された伝搬路予測優先度設定部２０５で行われる劣化予測方法について説明する。伝搬路計算値が伝搬路予測優先度設定部２０５に入力されると（ステップａ１）、空間ストリームの劣化しやすさの指標を計算し（ステップａ２）、劣化しやすさに基づいて各空間ストリームの優先度を設定する（ステップａ３）。
本実施の形態における空間ストリームは、空間多重における空間ストリームと各アンテナ間伝搬路と、また、周波数、時間多重による無線リソースを含む。
次に、本発明の第３の実施の形態に係る通信システムを具体的に説明する。
本発明の第３の実施の形態に係る通信システムは、特定の一つ又は複数の送受信機間における優先度付きデータの通信を行う。
ここで、説明の都合上、図１２Ａを参照すると、本発明の第３の実施の形態に係る通信システムは、切り換え部８０１、データ割付部８０２、優先度割付処理部８０３、切り換え部８０４、多重送信部８０５、制御部８０６、伝搬路推定部８０７、多重受信部８０９、優先度付き復号部８１０で構成される。
更に、優先度割付処理部８０３は、図１２Ｂに示すように、優先度割付部８１３，伝搬路予測優先度設定部８１４によって構成されている。
図１２Ａ，図１２Ｂ及び図１３を参照して、本発明の第３の実施の形態に係る通信システムの動作を説明する。尚、図１２Ａ及び図１２Ｂの破線は制御信号であり、図１３は制御部８０６の処理フローを表す。
制御部８０６は、データが入力されると（ステップｂ１）、優先度付きデータかどうかを判断し（ステップｂ２）、優先度付きデータでない場合は、切り換え部８０１、８０４に指示して優先度付き割付を無効にするように、データ割付部８０２にデータを送る（ステップｂ５）。制御部８０６はハードウェアで実現できるだけでなく、プログラムによって動作するマイクロプロセッサによっても実現できる。
ここで、優先度付きデータの定義は、各々関連する異なる優先度の複数のデータ列で構成されるデータである。優先度付きデータの優先度は、前述したように、重要度に応じて付けられる。
ここで、ステップｂ５の優先度付き割付を無効にするとは、従来通りの割付を行う事である。
データ割付部８０２は、伝搬路推定部８０８から送られる伝搬路情報に従って、データを空間ストリームに割り付ける。データ割付部８０２はハードウェアで構成されても良いし、ソフトウェアで実現されても良い。
多重送信部８０５は、各空間ストリームに割り付けられたきデータを、多重送信する。多重方法は、空間多重、周波数多重、時間多重がある。伝搬路８０７を通った信号は多重受信部８０９で受信され、優先度付き復号部８１０は受信信号を復号し、データを出力する。
また、制御部８０６は、伝搬路情報通知間隔τを初期値τ０に設定するよう伝搬路推定部８０８に指示する（ステップｂ６）。
伝搬路推定部８０８は、伝搬路８０７の特性を計算した伝搬路特性と、そこから求めた伝搬路情報を出力する。連続通信の場合の、伝搬路情報通知間隔をτとする。伝搬路特性は、伝搬路計算値、雑音情報、信号対雑音比などである。
伝搬路計算値は、既知信号もしくは、判定済み信号を疑似的に既知信号として用いて、伝搬路を経た受信信号に既知信号の複素共役を乗算して平均化する事により計算する。
また、伝搬路推定部８０８は、伝搬路情報通知間隔τに従って、伝搬路計算値と雑音計算値もしくは信号対雑音比から、システムで取り決めた値より選択して伝搬路情報を出力する。伝搬路情報は、伝搬路計算値及び雑音から計算される空間ストリーム毎の通信容量の指定であり、伝搬路情報の従来例として、通信レートを指定するＣＱＩ（Ｃｈａｎｎｅｌ Ｑｕａｌｉｔｙ Ｉｎｄｉｃａｔｏｒ）がある。
雑音計算値は、伝搬路計算値を用いて、受信信号電力から伝搬路電力値を引いて得られ、信号対雑音比は、伝搬路電力と雑音電力の比として得られる。
図１３のステップｂ２において、優先度付きデータの場合は、制御部８０６は、切り換え部８０１、８０４に指示して優先度付き符号化処理部８０３を有効にし、多重送信部８０５に出力することで優先度付き割付を有効にする（ステップｂ３）。
優先度割付処理部８０３の優先度度付きデータ割付部８１３（図１２Ｂ））は、優先度付きデータの優先度の高いデータ列から順次、優先度の高い空間ストリームに割り付ける。
優先度付きデータ割付には、伝搬路推定部８０８からの伝搬路情報で与えられる各空間ストリームに割り付けるデータ量も用いる。
図１２Ｂに示された優先度割付処理部８０３の伝搬路予測優先度設定部８１４は、伝搬路推定部８０８から通知される伝搬路特性から各空間ストリームの劣化し易さを予測し、劣化しにくいものに高く、劣化しやすいものに低い優先度を割り付け、各空間ストリームの優先度を出力する。
ここで、伝搬路特性とは、伝搬路計算値、雑音情報、信号対雑音比などであり、１度の計算から劣化しやすさを予測する場合は、値が比較値と比べて低いなどである。
また、繰り返し通信中においては、今回と前回の伝搬路計算値の変化から、各空間ストリームの安定性を判断して、安定した空間ストリームにはそうでない空間ストリームより高い優先度を設定する等の動作が行なわれる。
多重送信部８０５は、各空間ストリームに割り付けられたデータを、多重送信する。多重方法は、空間多重、周波数多重、時間多重がある。伝搬路８０７を通った信号は多重受信部８０９で受信され、優先度付き復号部８１０は受信信号を復号し、データを出力する。
また、図１３において、制御部８０６は、入力されたデータが優先度付きデータの場合は、伝搬路推定部８０８に指示して、伝搬路情報通知間隔τを初期値τ０より長い値に設定する（ステップｂ４）。
優先度付きデータの場合は、優先度付きデータ割付を行い、伝搬路情報通知間隔を長くする事により、逆方向の無線リソースを有効に活用する。
本実施の形態における空間ストリームは、空間多重における空間ストリームと各アンテナ間伝搬路と、また、周波数、時間多重による無線リソースを含む。
また、ステップｂ２における判断には、リアルタイム性が必要なデータかどうかを含んでも良い。例としては、リアルタイムアプリケーション用ＱｏＳであるＲＴ−ＶＲなど（参考文献１２参照）。Next, the best mode for carrying out the invention will be described in detail with reference to the drawings.
The communication system according to the first embodiment of the present invention performs prioritized data communication between one or more specific transceivers. Referring to FIG. 1, the first embodiment of the present invention includes a priority assignment unit 101, a spatial multiplexing transmission unit 102, a spatial multiplexing reception unit 103, a priority decoding unit 104, and a propagation path estimation unit. 106 and a propagation path prediction priority setting unit 105.
The propagation path 107 is a spatial multiplexing propagation path that performs communication between one or more specific transceivers, and may change with time.
The channel prediction priority setting unit 105 and the channel estimation unit 106 may be on either the transmission side or the reception side. For example, in the frequency division duplex method (FDD method), a propagation path estimation unit is required on the receiving side, but in the time division duplex method (TDD method), uplink and downlink are the same propagation path, so both transmission and reception sides are possible. It is.
The operation in the first embodiment shown in FIG. 1 will be schematically described.
First, the data with priority is composed of a plurality of data strings having different priorities.
Here, the priority of the data is given according to the importance of the data. For example, in video information in which audio information and image information are mixed, audio information has a higher priority than image information. In scalable encoded data, priority is given to the data with the lowest quality and the smallest amount called the base layer. The degree of priority is higher than the enhancement layer for improving quality.
In the case of communication with priority data, the following operation is performed to lengthen the propagation path information update cycle. First, the priority assignment unit 101 assigns the data with priority to the spatial stream in order from the highest priority.
Here, according to the present invention, priorities are also assigned to the spatial streams, and the priority assigning unit 101 according to this embodiment is configured so that the prioritized data is a space having a higher priority in order from the higher priority. Assign to a stream.
The spatial multiplexing transmission unit 102 forms multiple spatial streams using multiple antenna elements or multiple polarizations of a single antenna element, and performs spatial multiplexing transmission. Spatial multiplexing methods include a method that does not perform weight multiplication (such as SDM) and a method that performs weight multiplication (such as W-SDM and E-SDM).
The propagation path estimation unit 106 uses a known signal or a determined signal as a pseudo known signal, multiplies the complex conjugate of the known signal, and averages the signals, so that the transmission / reception antennas (or polarizations) are connected. Calculates the characteristics of the spatial multiplex propagation path in and outputs the propagation path calculation value.
The propagation path prediction priority setting unit 105 predicts the ease of deterioration of each spatial stream from the propagation path calculation value, and assigns a low priority to those that are difficult to deteriorate and those that are easy to deteriorate.
The spatial multiplexing receiving unit 103 receives signals using polarized waves of a plurality of antenna elements or single antenna elements, and separates the spatially multiplexed signals by signal processing.
The decoding unit with priority 104 decodes the encoded signal with priority. Decoding with priority is a communication hindrance when information with high priority is erroneous due to changes in propagation path characteristics, but information with low priority is erroneous, and communication with high priority is correctly propagated, resulting in quality degradation. Become a success.
Therefore, in the present invention, by assigning a priority to a spatial stream, an error due to a decrease in followability of propagation path characteristics can be biased to a low priority part of data with priority. As a result, communication resources are effectively used by reducing communication frequency in the reverse direction for propagation path information update without impeding communication, and in E-SDM, the reflection frequency of propagation path characteristics to transmission weights is reduced. By reducing the number of calculations and making it difficult to inhibit communication, it is possible to reduce the occurrence of delay due to retransmission control.
Next, the overall operation of the present embodiment will be described in detail with reference to FIGS.
The first embodiment of the present invention is for the case of communicating data with priority for personal communication between one or more specific transceivers.
Referring to FIG. 1, the priority-added data transmitted and received in the first embodiment of the present invention is composed of a plurality of data strings with associated priorities. The priority of the data string is given according to the importance of the information. As described above, in video information in which audio information and image information are mixed, audio information has a higher priority than image information. In scalable encoded data, data of the lowest quality and a small amount of data called a base layer is used. The priority is higher than the enhancement layer for improving the quality.
In the priority assigning unit 101, the data with priority is sequentially assigned to the spatial stream with high priority from the data string with high priority.
The data with priority assigned to each spatial stream is multiplied by the weight calculated from the propagation path calculation value in the spatial multiplexing transmission section 102 using a plurality of antenna elements or a plurality of polarizations of a single antenna element, and is spatially multiplexed. Is done.
A specific weight calculation method for E-SDM, which is one of the methods for multiplying weights, will be described. Calculation of propagation path value hkj (k = k = transmission antenna j and reception antenna k transmitted from propagation path estimation unit 106) 1, 2,..., N, j = 1, 2,.

A common eigenvalue λi (i = 1, 2,..., ^M) of correlation matrices H ^H H and HH ^H is obtained by using singular value decomposition or the like.
{·} ^H represents a complex conjugate transpose of a matrix.
Eigenvector _{e t} for the eigenvalues λi of the correlation matrix ^{H H} _{H, i,} eigenvector _{e r} for the eigenvalues λi of the correlation matrix HH _^H, with _i, the sender weight _{E t} and the receiving weights _E ^{r H} be set below Eigenvalue transmission is performed with.

At this time, the relationship between the information Si allocated to the i-th spatial stream and the signal xj transmitted by the transmitting antenna (or polarization) j is as follows.

Here, yt, i, j (i = 1, 2,..., M, j = 1, 2,... M) are elements of the eigenvectors et _{, i} of the spatial stream λi, and αi is the power of each spatial stream. This is the gain used for control.
W-SDM performs only transmission power control and transmission rate control on the transmission side based on propagation path characteristics. Therefore, the number of spatial streams m = M, and αi is only controlled for each spatial stream.
X = S Equation 27

The propagation path 107 is a spatial multiplexing propagation path.
The propagation path estimation unit 106 uses a known signal or a determined signal as a pseudo known signal, multiplies the complex conjugate of the known signal, and averages the signals, so that the transmission / reception antennas (or polarizations) are connected. Calculates the characteristics of the spatial multiplex propagation path in and outputs the propagation path calculation value.
In other words, the propagation path estimation unit 106 performs an operation of multiplying a signal passing through the propagation path by a complex conjugate of a known signal or a pseudo known signal, and averaging to calculate the propagation path characteristics in order to remove the influence of noise. As a result, a propagation path calculation value hkj (k = 1, 2,... N, j = 1, 2,... M) between the transmitting antenna j and the receiving antenna k is obtained. A propagation path matrix H is obtained using this propagation path calculation value.
Next, the propagation path prediction priority setting unit 105 predicts the easiness of deterioration of each spatial stream from the propagation path calculation value, and assigns a lower priority to the easy to deteriorate and a lower priority to the easy to deteriorate. Assign as degrees.
The deterioration prediction method in the propagation path prediction priority setting unit 105 will be described based on the flowchart of FIG. 2. When a propagation path calculation value is input (step a1), an index of the degree of deterioration of the spatial stream is calculated. (Step a2), the priority of each spatial stream is set based on the ease of deterioration (Step a3).
The operations of the propagation path estimation unit 106, the propagation path prediction priority setting unit 105, and the priority assignment unit 101 described above can be realized not only by a hardware circuit but also by software. The same applies to other embodiments described below.
The spatial multiplexing receiver 103 receives signals using the polarizations of a plurality of antenna elements or single antenna elements, and separates the signals that have been spatially multiplexed by signal processing. The decoding unit with priority 104 decodes the encoded signal with priority.
Decoding with priority is a communication hindrance when high priority information is wrong due to changes in propagation path characteristics, but quality degradation occurs when high priority information is correctly propagated even if low priority information is wrong. It becomes communication success only by becoming.
Therefore, the system according to the present invention can bias an error due to a decrease in followability of propagation path characteristics to a low-priority portion of priority-added data by priority assignment. As a result, even if low priority information is incorrect, communication is not hindered, and the reflection frequency of propagation path characteristics with respect to transmission weights can be reduced.
Next, the best mode for carrying out the second invention of the present invention will be described in detail with reference to the drawings.
The second embodiment of the present invention relates to prioritized data communication between one or more specific transceivers. Referring to FIG. 3, the operation of the second embodiment of the present invention is as follows. The data with priority is information composed of a plurality of data strings having different priorities.
In this embodiment, the priority given to the data string is given according to the importance of the data string. For example, in video information in which audio information and image information are mixed, audio information has a higher priority than image information, and in scalable encoded data, the priority of the data with the lowest quality and the smallest amount called the base layer is , Higher priority than the enhancement layer to improve quality.
The priority-assigned data is assigned to a spatial stream with a high priority in the priority assignment unit 201 sequentially from a data string with a high priority.
The data with priority assigned to each spatial stream is multiplexed and transmitted by the multiplexing transmission unit 202. Multiplexing methods include spatial multiplexing, frequency multiplexing, and time multiplexing.
The propagation path estimation unit 206 uses the known signal or the determined signal as a pseudo known signal and multiplies the signal that has passed through the propagation path by the complex conjugate of the known signal and averages each propagation path. And calculate the propagation path calculation value.
This embodiment is different from FIG. 1 in that the propagation path calculation value is notified to the propagation path prediction priority setting unit 205 and is not notified to the multiplex transmission unit 202.
The propagation path prediction priority setting unit 205 predicts the easiness of deterioration of each spatial stream from the notified propagation path characteristics, assigns a higher priority to those that are less likely to deteriorate, and assigns a lower priority to those that are more likely to deteriorate, and each spatial stream. The priority of is output.
Here, the propagation path characteristic is a signal-to-noise ratio or the like, and the value is lower than the comparison value when predicted from a single calculation.
In addition, during repeated communication, the stability of each spatial stream is judged from the change in the propagation path calculation value this time and the previous time, and a higher priority is given to a stable spatial stream than a spatial stream that is not so. is there.
In a state in which packets are repeatedly transmitted and received during communication, the propagation path calculation value is repeatedly calculated to reset the priority of the spatial stream.
With reference to the flowchart shown in FIG. 2 again, the degradation prediction method performed in the propagation path prediction priority setting unit 205 shown in FIG. 3 will be described. When the propagation path calculation value is input to the propagation path prediction priority setting unit 205 (step a1), an index of the ease of degradation of the spatial stream is calculated (step a2), and each spatial stream is based on the ease of degradation. Is set (step a3).
The spatial stream in the present embodiment includes a spatial stream in spatial multiplexing, a propagation path between antennas, and radio resources by frequency and time multiplexing.
Next, a communication system according to the third embodiment of the present invention will be specifically described.
The communication system according to the third embodiment of the present invention performs communication of data with priority between specific one or a plurality of transceivers.
Here, for convenience of description, referring to FIG. 12A, a communication system according to the third exemplary embodiment of the present invention includes a switching unit 801, a data allocation unit 802, a priority allocation processing unit 803, a switching unit 804, and a multiplexing unit. A transmission unit 805, a control unit 806, a propagation path estimation unit 807, a multiple reception unit 809, and a priority decoding unit 810 are configured.
Furthermore, the priority assignment processing unit 803 includes a priority assignment unit 813 and a channel prediction priority setting unit 814 as illustrated in FIG. 12B.
The operation of the communication system according to the third embodiment of the present invention will be described with reference to FIGS. 12A, 12B, and 13. 12A and 12B are control signals, and FIG. 13 shows a processing flow of the control unit 806.
When data is input (step b1), the control unit 806 determines whether the data has priority (step b2). If the data is not prioritized, the control unit 806 instructs the switching units 801 and 804 to give priority. Data is sent to the data allocation unit 802 so as to invalidate the allocation (step b5). The control unit 806 can be realized not only by hardware but also by a microprocessor that operates according to a program.
Here, the definition of data with priority is data composed of a plurality of data strings having different priorities. As described above, the priority of the data with priority is given according to the importance.
Here, disabling the allocation with priority in step b5 is to perform the conventional allocation.
The data allocation unit 802 allocates data to the spatial stream according to the propagation path information sent from the propagation path estimation unit 808. The data allocation unit 802 may be configured by hardware or may be realized by software.
The multiplex transmission unit 805 multiplex-transmits the data assigned to each spatial stream. Multiplexing methods include spatial multiplexing, frequency multiplexing, and time multiplexing. The signal that has passed through the propagation path 807 is received by the multiple receiver 809, and the decoding unit with priority 810 decodes the received signal and outputs data.
In addition, the control unit 806 instructs the propagation path estimation unit 808 to set the propagation path information notification interval τ to the initial value τ0 (step b6).
The propagation path estimation unit 808 outputs propagation path characteristics obtained by calculating the characteristics of the propagation path 807 and propagation path information obtained from the propagation path characteristics. Let τ be the channel information notification interval in the case of continuous communication. The propagation path characteristics include a propagation path calculation value, noise information, a signal-to-noise ratio, and the like.
The propagation path calculation value is calculated by using the known signal or the determined signal as a pseudo known signal and multiplying the reception signal that has passed through the propagation path by the complex conjugate of the known signal and averaging.
Further, the propagation path estimation unit 808 selects the propagation path calculated value and the calculated noise value or the signal-to-noise ratio from the values determined by the system according to the propagation path information notification interval τ, and outputs the propagation path information. The propagation path information is a designation of the communication capacity for each spatial stream calculated from the propagation path calculation value and the noise. As a conventional example of the propagation path information, there is CQI (Channel Quality Indicator) for designating a communication rate.
The calculated noise value is obtained by subtracting the propagation path power value from the received signal power using the propagation path calculation value, and the signal-to-noise ratio is obtained as the ratio of the propagation path power and the noise power.
In step b2 in FIG. 13, in the case of data with priority, the control unit 806 instructs the switching units 801 and 804 to enable the coding processing unit 803 with priority and outputs it to the multiplex transmission unit 805. The allocation with priority is validated (step b3).
The priority-assigned data assigning unit 813 (FIG. 12B) of the priority assigning processing unit 803 assigns the data with priority to the spatial stream having the highest priority sequentially from the data sequence having the highest priority.
For the data assignment with priority, the data amount assigned to each spatial stream given by the propagation path information from the propagation path estimation unit 808 is also used.
The propagation path prediction priority setting unit 814 of the priority assignment processing unit 803 shown in FIG. 12B predicts the ease of deterioration of each spatial stream from the propagation path characteristics notified from the propagation path estimation unit 808, and deteriorates. High priority is assigned to difficult ones, and low priority is assigned to those that are likely to deteriorate, and the priority of each spatial stream is output.
Here, the propagation path characteristics are propagation path calculation values, noise information, signal-to-noise ratio, etc. When predicting the ease of deterioration from a single calculation, the value is lower than the comparison value. is there.
In addition, during repeated communication, the stability of each spatial stream is judged from the change in the propagation path calculation value this time and the previous time, and a higher priority is set for a stable spatial stream than a spatial stream that is not so. Operation is performed.
The multiplex transmission unit 805 multiplex-transmits the data allocated to each spatial stream. Multiplexing methods include spatial multiplexing, frequency multiplexing, and time multiplexing. The signal that has passed through the propagation path 807 is received by the multiple receiver 809, and the decoding unit with priority 810 decodes the received signal and outputs data.
In FIG. 13, when the input data is data with priority, the control unit 806 instructs the propagation path estimation unit 808 to set the propagation path information notification interval τ to a value longer than the initial value τ0. (Step b4).
In the case of data with priority, data allocation with priority is performed, and the radio resource in the reverse direction is effectively utilized by increasing the propagation path information notification interval.
The spatial stream in the present embodiment includes a spatial stream in spatial multiplexing, a propagation path between antennas, and radio resources by frequency and time multiplexing.
Further, the determination in step b2 may include whether or not the data requires real-time characteristics. An example is RT-VR, which is QoS for real-time applications (see Reference Document 12).

表２に、ｍ＝４の場合の優先度設定例を示す。最大固有値λｍａｘ＝９であり、このときｉ＝２なので、ＰＳ２＝２とし、λｍｉｎ＝０．２５で、このときｉ＝１なのでＰＳ２＝２とし、最大固有値の空間ストリームと最小固有値の空間ストリームの優先度を下げる。

また、伝搬路行列作成（ステップＳ３）と固有値計算（ステップＳ４）は、受信側の送信多重部もしくは送信側の送信多重部との共用ができる。
図５のフローチャートに基づいて、繰り返し通信中のＥ−ＳＤＭの劣化予測方法について説明する。ここで云う繰り返し通信中とは、例えば、複数パケットにまたがるデータ通信である。これは、図２の具体例であり、図１の伝搬路予測優先度設定部１０５の動作である。
繰り返し通信中において、前回の伝搬路計算値から計算した固有値、固有ベクトルと今回の伝搬路計算値から計算した固有値、固有ベクトルの変化から、各空間ストリームの安定度を予測し安定度の高い空間ストリームの優先度を上げ、不安定な空間ストリームの優先度を下げる方法である。
まず、前回の固有ベクトルｅｕ（ｎ−１）（ｉ＝１，２，…ｍ，ｕ＝１，２，…，ｍ（ｎ−１））が保持されている（ステップＳ１１）。ここでｍ（ｎ−１）は、前回の固有値の数である。
伝搬路予測優先度設定部１０５は、第ｎ回の伝搬路計算値ｈｋｊ（ｎ）が入力されると（ステップＳ１２）、伝搬路計算値ｈｋｊ（ｎ）を配置して伝搬路行列Ｈ（ｎ）を作成し（ステップＳ１３）、固有ベクトル計算を行い、固有値数ｍ及び固有ベクトルｅｉ（ｉ＝１，２，…，ｍ）を決定する（ステップＳ１４）。固有ベクトルの計算方法には、特異値分解、Ｈｏｕｓｅｈｏｌｄｅｒ、ＱＲ分解、ＤＢ法などがある。各固有ベクトルｅｉの長さは送信側固有ベクトルでは送信側アンテナ数Ｍとなり、受信側固有ベクトルで行う場合は、受信側アンテナ数Ｎとなる。劣化予測はどちらを用いることも可能なため、本説明では、どちらの場合も固有ベクトル相関量計算を行い、空間ストリーム毎に最大の固有ベクトル相関量を選択する事で、前回の空間ストリーム番号ｕと今回の固有ストリーム番号ｉの関連づけを行う。

ただし、ここでｅ_ｉ（ｎ），ｅ_ｕ（ｎ−１）は正規化された値である。つまり、

各ｉに対してΔｅ_ｉｕが最大となるｕを選択し、そのときのｕをｉ（ｎ−１）とする（ステップＳ１６）。
更に、しきい値ΔｅｔｈＬを定め、Δｅ_{ｉｉ（ｎ−１）}がしきい値ΔｅｔｈＬより低い場合（ステップＳ１８）、前回の第ｉ（ｎ−１）空間ストリームと今回の第ｉ空間ストリームは連続する空間ストリームではないと判断し、第ｉ空間ストリームは不安定であると判断して低い優先度を設定する（ステップＳ１９）。
ＰＳｉ＝３ 式３５
また、しきい値ΔｅｔｈＨを定め、Δｅ_{ｉｉ（ｎ−１）}がしきい値ΔｅｔｈＨより高い場合（ステップＳ２０）、前回の固有ベクトルと今回の固有ベクトルの相関が充分に高いと判断し、高い優先度を設定する（ステップＳ２１）。
ＰＳｉ＝１ 式３６
Δｅ_{ｉｉ（ｎ−１）}がΔｅ_ｔｈＬ＜Δｅ_{ｉｉ（ｎ−１）}＜Δｅ_ｔｈＨの空間ストリームには、中程度の優先度を設定する。
ＰＳｉ＝２ 式３７
ｉ＝１からｍまでの全空間ストリームに関して行う（ステップＳ１７，Ｓ２３）。
最大固有値λｍａｘを求め（ステップＳ２４）、関連する空間ストリームの優先度ＰＳｍａｘを下げる（ステップＳ２５）。
これは、最大固有値は劣化しやすく、また、特に記載してないが最大送信電力を割り付けるために、相関の劣化によるストリーム間干渉電力も大きくなるためである（非特許文献３参照）。
図６のフローチャートに基づいて、図２の具体例である繰り返し通信中のＷ−ＳＤＭの劣化予測方法について説明する。
これは、図３の伝搬路予測優先度設定部２０５の動作である。
Ｗ−ＳＤＭは、伝搬路特性から送信電力制御や適応変調を行うのみであるため、空間ストリームは送信アンテナ毎になり、空間ストリーム番号ｉはアンテナ番号ｊと等しいと考える。
先の時間に計算した伝搬路計算値ｈｊｋ（ｎ−１）が保持されている（ステップＳ２６）。今回計算した伝搬路計算値ｈｊｋ（ｎ）が入力される（ステップ２７）。アンテナｊの伝搬路変化量Δｈｊ（ｎ）を計算する（ステップＳ２８）。但し、この式は伝搬路計算値が規格化された値でない場合に用いる。

各アンテナの伝搬路変化量を比較し、大きな値のアンテナから順次高い優先度を設定する（ステップＳ２９）。
特に、Δｈｊ（ｎ）がマイナスの値の場合は縮小した事を示すので、劣化すると予測し、低い優先度を設定する。
具体例を表３に示すと、伝搬路変化量Δｈｊ（ｎ）が最も大きい空間ストリーム番号３の優先度を最大の１とし、続いて空間番号２，１、４の順に優先度を低く設定する。

図１の伝搬路予測優先度設定部１０５の動作及び図２の具体例として、繰り返し通信中の例を示すと、先の回に計算した伝搬路計算値から求めた先の固有値と、今回の伝搬路計算値から求めた今回の固有値を比較し、大きく変化した固有値に関連する空間ストリームは、あまり変化しない固有値の空間ストリームより劣化しやすいと予測して優先度を低く設定する。
また、縮小した固有値に関連する空間ストリームは劣化すると予測して優先度を低く設定する等、空間ストリームの優先度の割付には種々の手法を使用することができる。
図７Ａ〜図７Ｅを参照して、本発明に係る他の実施例を説明する。
ここでは、優先度付きデータが特定の送信側３０１から受信側無線局３０２に送信される例が示されている。優先度付きデータは、各々異なる優先度の複数のデータ列で構成されているものとする。
伝搬路予測優先度設定部３０５は、伝搬路計算値から各空間ストリームの劣化し易さを予測し、劣化しにくいものに高く、劣化しやすいものに低い優先度を割り付ける。
優先度割付部３０４は、優先度付きデータの優先度の高いものから順次、優先度の高い空間ストリームに割り付ける。割付の際、データ数が合わないとデータ配分の調整を行う。上記した伝搬路予測優先度設定部３０５及び優先度割付部３０４は、前述した実施例と同様に、ハードウェアによって実現されても良いし、ソフトウェアプログラムによって実現されても良い。
以下に表を用いて具体的に説明する。
表４，表５に優先度付きデータとそのビット数、空間ストリームの優先度と送信ビット数の例を示す。
優先度付きデータは、本明細書の背景技術で説明したように空間スケーラビリティ、時間スケーラビリティ、ＳＮＲスケーラビリティ、ＲＯＩスケーラビリティ等に基くものがあり、また、ビデオ配信において音声と画像が同時配信される場合は、音声の優先度は画像より高いとする。また、これらのスケーラビリティ、データタイプの複合型もある。優先度の表し方はシステムにより異なるが、この例では、優先度が高い事を小さな番号で表している。
表４によると、最も解像度が低い基本レイヤと、その解像度を順次上げる冗長データの第１拡張レイヤと第２拡張レイヤがある。優先度は情報の重要度に従い、基本レイヤがもっとも高く、１とする。サービス品質（ＱｏＳ）が低いものほど、優先度は高い傾向となる。一方、第ｉ空間ストリームの優先度は、伝搬路予測優先度設定部３０５が設定する。
送信ビット数は、伝搬路情報によって指定される。表５はその例である。
優先度割付部３０４は、最も優先度の高い優先度付きデータから順次、優先度の高い空間ストリームに割り振るので、優先度１の基本レイヤを優先度１の第２空間ストリームに割り振る。
データ列のデータ数が異なるため、第２空間ストリームには、基本レイヤ１２８ビットに引き続いて第１拡張レイヤの冗長データの前半２５６ビットの合計３８４ビットが割り振られる。続いて、第１拡張レイヤの冗長データの残り１２６ビットを優先度２の第３空間ストリームに割り振り、続いて、第２拡張レイヤの冗長データを優先度３及び４の第１空間ストリームと第４空間ストリームに割り振られる。
このように、優先度割付部３０４は、データ調整機能を有する場合がある。

図７Ａ〜図７Ｅに示されたチャネル符号化部３０２は、空間ストリーム毎に割り振られたデータそれぞれに、受信側で誤りがないか検査できるようにチャネル符号化し、空間多重送信部３０６に送る。
空間多重送信部３０６は図７Ｂに示されたように、ウェイト乗算部３２０、既知信号挿入変調部３２１、ウェイト生成部３２２を備えている。ウェイト生成部３２２は伝搬路情報からＭ×ｍの送信ウェイトＷｔを設定し、ウェイト乗算部３２０で各々の空間ストリームで送信するチャネル符号化したデータｂｉ（ｉ＝１，２，…，ｍ）に送信ウェイトを掛けてアンテナ送信信号ｔｉ（ｉ＝１，２，…，ｍ）とする。

既知信号挿入変調部３２１はウェイトを掛けた信号に既知信号を挿入し、方式によって、ＣＤＭＡもしくはＯＦＤＭＡなどの変調を行い、必要に応じて無線搬送波周波数に周波数変換し、送信空間多重アンテナ３０７から空間多重伝搬路３０８に送信する。
送信空間多重アンテナ３０７は、複数アンテナ素子による構成と、単一アンテナの複数偏波を利用する構成方法がある。
空間多重伝搬路３０８で、多重送信した複数のデータ列は、複数ストリームによって伝送されるが、空間多重伝搬路３０８では、伝搬損失やマルチパスやフェージング、シャドウイングなどが生じる。
受信側３０２では、電波を受信空間多重アンテナ３０９を介して空間多重受信部３１０で受信する。受信する際、熱雑音も加わる。
空間多重受信部３１０は、図７Ｃに示されているように、復調部３２３とウェイト乗算部３２４とを備え、復調部３２３では、送信側の変調に合わせてＣＤＭＡ、ＯＦＤＭ等の復調を行い、必要に応じて信号処理可能な周波数に変換する。一方、空間多重受信部３１０のウェイト乗算部３２４では復調信号にウェイトを乗算する。
受信側無線局３０２の伝搬路推定部３１４は、図７Ｄに示すように、伝搬路計算部３２５、ウェイト生成部３２６、及び、伝搬路情報生成部３２７を備えている。伝搬路推定部３１４の伝搬路計算部３２５では、送信側で挿入された既知信号もしくは疑似既知信号として扱うことのできる判定後信号を用い、復調信号に既知信号の複素共役を乗算して平均化して伝搬路計算値を得、伝搬路推定値としてウェイト生成部３２６に出力する。ウェイト生成部３２６は、伝搬路推定値から、ウェイトを計算する。ウェイトの計算方法は、Ｅ−ＳＤＭ、ＺＦ、ＭＭＳＥなどがある。
伝搬路推定部３１４の伝搬路情報生成部３２７は、伝搬路計算値もしくはウェイトを元に送信側に送る伝搬路情報を、システムで取り決めた値より選択し出力する。
伝搬路情報は、伝搬路計算値及び雑音から計算される空間ストリーム毎の通信容量と送信側ウェイトの指定であり、伝搬路情報の従来例としては通信レートを表示するＣＱＩ（Ｃｈａｎｎｅｌ Ｑｕａｌｉｔｙ Ｉｎｄｉｃａｔｏｒ）、ウェイトを通知するＰＣＩ（Ｐｒｅｃｏｄｉｎｇ ｃｏｎｔｒｏｌ ｉｎｄｉｃａｔｏｒ）やＣｏｄｅｂｏｏｋ Ｉｎｄｅｘがある。
伝搬路情報から空間ストリームの劣化しやすさを予測し優先度を決定する。劣化しやすさは、最大ウェイトを掛ける空間ストリームは劣化しやすい、先の伝搬路情報と比較して容量やウェイト設定の変化の大きい空間ストリームは劣化しやすいなどである。
図７Ａに示された優先度付きチャネル復号部３１１は、空間ストリームの優先度に従い、空間ストリーム毎にチャネル復号する。優先度の最も高い空間ストリームの復号が失敗すると通信阻害信号を出力し、成功すると通信阻害信号を出力しない。通信阻害信号は受信側再送制御部３１６に通知される。
受信側再送制御部３１６は、通信阻害がなければ再送要求せず、通信阻害があると受信側送信部に再送要求信号を出力する。
優先度付き復号部３１２では、優先度付きチャネル復号部３１１において通信阻害信号の出力がないとき、優先度付きチャネル復号を行う。同一情報の優先度付きデータの場合、基本レイヤが通信できておらず拡張レイヤを復号しても無効なため、以降の復号を中断し、復号したデータのみを表示部３１３に送る。
優先度が最高の優先度付きデータが優先度の最も高い空間ストリームで終了せず、続く空間ストリームの復号が失敗した場合は、優先度付きチャネル復号部３１２が通信阻害信号を出力する。通信阻害がある場合は、復号処理を停止して再送データの受信を待つ。
優先度が最高の優先度付きデータは正しく復号でき優先度の低い優先度付きデータの復号に失敗した場合は、通信阻害信号は出力しない。表示部３１３は、画像の場合はディスプレイ、音声の場合はマイクなどである。
受信側無線局３０２からの伝搬路情報は、アンテナ３１８と逆方向伝搬路３１９を通してアンテナ３２８で受信され、送信側受信部３２９で受信され、空間多重送信部３０６のウェイト生成部３２２と、伝搬路予測優先度設定部３０５に通知される。
また、通信阻害が発生した場合、再送要求信号が受信側送信部３１７、アンテナ３１８、逆方向伝搬路３１９、アンテナ３２８、送信側受信部３２９を経て送信側再送制御部３３０に伝えられ、送信側再送制御部は、通信阻害のあったデータを再送する。
このとき、逆方向伝搬路３１９は、ＦＤＤ方式では伝搬路３０８とは異なる周波数であり、ＴＤＤ方式では同一周波数である。
また、アンテナ３１８、３２７が空間多重アンテナで逆方向伝搬路３１９が空間多重伝搬路の場合もそうでない場合もある。
図７Ｅには、図７Ｂに示された空間多重送信部３０６とは異なる構成を有する空間多重送信部３０６の例が示されている。図７Ｅに示された空間多重送信部３０６は、既知信号挿入部３３１、ウェイト乗算部３３２、変調部３３３を備えると共に、図７Ｂと同様にウェイト生成部３２２を有している。図７Ｅからも明らかなように、既知信号挿入部３３１で挿入される既知信号の挿入位置が異なっている例である。
図７Ｅに示された例では、空間多重送信部３０６に設けられた既知信号挿入部３３１は、空間ストリーム毎に符号化した信号に既知信号を挿入し、その後、ウェイト乗算部３３２はウェイトを乗算し、変調部３３３はＣＤＭＡ、ＯＦＤＭなどの変調を行う。
この例では、優先度の低いデータは確実な送信を保証しないバックグラウンドやベストエフォートであり、ここでは代表してベストエフォートと呼ぶことにする。また、優先度の高いデータは確実な送信を保証するデータであり、代表してギャランティと呼ぶことにする。
一方、優先度の低いデータのＱｏＳがバックグラウンドで優先度の高いデータのＱｏＳも送信を保証しないタイプのベストエフォートの場合は、
再送制御は行わない。その場合は、送信側制御部３３０、受信側送信部３１７は不要であり、遅延時間は更に削減できる。全てのデータがベストエフォートであっても、ベストエフォートの中で優先度の高いデートを優先度の高い空間ストリームに割り当てることによって優先度の高いデータが伝送し易くなるという効果が得られる。
これは、ベストエフォートの定義が、ベストエフォートとそれよりＱｏＳの低いバックグラウンドを含む場合、また、同じベストエフォートの中でもレベルと言われる更に細かい段階分けをする場合に相当する。
この実施例の効果は、送信側での伝搬路推定頻度を減らしても、再送制御による遅延を削減できる事である。その理由は、伝搬路特性の時間変化によって劣化しにくい空間ストリームに優先度の高い優先度付きデータを割り振るために、誤りを優先度の低い優先度付きデータに偏らせる事ができるため、優先度の高い優先度付きデータは正しく通信でき、再送制御を行わないためである。
図８Ａ〜図８Ｅを参照して、本発明に係る他の実施例を説明する。
図示された実施例は、優先度付きデータを、特定の送信側無線局４０１から受信側無線局４０２に通信する例である。優先度付きデータは、重要度に応じた優先度を設定された複数のデータ列で構成される。優先度割付部４０４は、優先度付きデータの優先度の高いものから順次、優先度の高い空間ストリームに割り付ける。空間ストリームの優先度情報は優先度付き伝搬路情報で与えられる。その際、データ数が合わない時のデータ配分調整方法は、図７Ａに示した優先度割付部３０４と同様な方法で行われる。
チャネル符号化部４０５は、空間ストリーム毎に割り振られたデータそれぞれに、受信側で誤りがないか検査できるようにチャネル符号化し、変調空間多重送信部４０６に送る。
空間多重送信部４０６では、図８Ｂに示すように、優先度付き伝搬路情報からウェイト生成部４２２がｍ×ｍの送信ウェイトＷｔを設定し、ウェイト乗算部４２０で各々の空間ストリームで送信するチャネル符号化したデータｂｉ（ｉ＝１，２，…，ｍ）に送信ウェイトを掛けてアンテナ送信信号ｔｉ（ｉ＝１，２，…，ｍ）とする。
詳細動作は図７Ａ〜図７Ｅに示した空間多重送信部３０６と同様である。
即ち、図８Ｂに示すように、空間多重送信部４０６の既知信号挿入変調部４２１はウェイトを掛けた信号に既知信号を挿入し、方式によって、ＣＤＭＡもしくはＯＦＤＭＡなどの変調を行い、必要に応じて無線搬送波周波数に周波数変換し、送信空間多重アンテナ４０７から空間多重伝搬路４０８に送信する。
送信空間多重アンテナ４０７は、複数アンテナ素子による構成と、単一アンテナの複数偏波を利用する構成方法がある。
空間多重伝搬路４０８で、多重送信した複数のデータ列は、複数ストリームによって伝送される。空間多重伝搬路４０８では、伝搬損失やマルチパスやフェージング、シャドウイングなどが生じ、空間多重伝搬路４０８の特性は時間と共に変化する。
受信側無線局４０２では、受信空間多重アンテナ４０９で電波を受信する。
このとき熱雑音が加わる。図８Ｃに示されているように、空間多重受信部４１０の復調部４２３では、送信側の変調に合わせてＣＤＭＡ、ＯＦＤＭ等の復調を行い、必要に応じて信号処理可能な周波数に変換する。ウェイト乗算部４２４では復調信号にウェイトを乗算する。
次に、図８Ｄに示された伝搬路推定部４１４では、伝搬路計算部４２５で、送信側で挿入された既知信号もしくは疑似既知信号として扱うことのできる判定後信号を用い、復調信号に既知信号の複素共役を乗算して平均化して伝搬路計算値を得る。
更に、図８Ｄに示された伝搬路推定部４１４のウェイト生成部４２６は、伝搬路推定値から、ウェイトを計算する。ウェイトの計算方法は、Ｅ−ＳＤＭ、ＺＦ、ＭＭＳＥなどがある。
優先度付き伝搬路情報生成部４２７は、伝搬路計算値もしくはウェイトを元に送信側に送る伝搬路情報を、システムで取り決めた値より選択する。また、伝搬路予測優先度設定部４１５から受け取った空間ストリーム優先度情報を合わせて優先度付き伝搬路情報を出力する。
伝搬路情報は、伝搬路計算値及び雑音から計算される空間ストリーム毎の通信容量と送信側ウェイトの指定であり、伝搬路情報の従来例としてはＣＱＩ、ＰＣＩなどがある。
このとき、伝搬路情報のビット数をｆビットとすると、優先度付き伝搬路特性は、伝搬路情報ｆビットに優先度情報ｇビットを付加する。
例として、空間ストリームの個数がｍ＝４の場合に、最も優先度の高い空間ストリーム番号を優先度情報として付加すると、２ビットで通知可能なので、ｇ＝２ビットを付加する。伝搬路情報が６ビットの場合、それに優先度情報２ビットを足して８ビットで通知する。
図８Ａに示された伝搬路予測優先度設定部４１５は、伝搬路計算値から空間ストリームの劣化しやすさを予測して優先度を決定する。劣化しやすさの予測方法としては、先に図７Ａ〜図７Ｅ及び図４を参照して説明した方法がある。
更に、最大ウェイトを掛ける空間ストリームは劣化しやすいこと、先の伝搬路情報と比較して容量やウェイト設定の変化の大きい空間ストリームは劣化しやすいこと等を利用して、劣化しやすさを予測しても良い。
優先度付きチャネル復号部４１１は、空間ストリームの優先度に従い、空間ストリーム毎にチャネル復号する。優先度の最も高い空間ストリームの復号が失敗すると通信阻害信号を出力し、成功すると通信阻害信号を出力しない。通信阻害信号は受信側再送制御部４１６に通知される。
受信側再送制御部４１６は、通信阻害がなければ再送要求せず、通信阻害があると受信側送信部に再送要求信号を出力する。
優先度付き復号部４１２では、優先度付きチャネル復号部４１１において通信阻害信号の出力がないとき、優先度付きチャネル復号を行う。同一情報の優先度付きデータの場合、基本レイヤが通信できておらず拡張レイヤを復号しても無効なため、以降の復号を中断し、復号したデータのみを表示部４１３に送る。
優先度が最高の優先度付きデータが優先度の最も高い空間ストリームで終了せず、続く空間ストリームの復号が失敗した場合は、優先度付きチャネル復号部４１２が通信阻害信号を出力する。通信阻害がある場合は、復号処理を停止して再送データの受信を待つ。
優先度が最高の優先度付きデータは正しく復号でき優先度の低い優先度付きデータの復号に失敗した場合は、通信阻害信号は出力しない。表示部４１３は、画像の場合はディスプレイ、音声の場合はマイクなどである。
図示された例では、伝搬路情報は、アンテナ４１８と逆方向伝搬路４１９を通してアンテナ４２８で受信され、送信側受信部４２９で受信され、図８Ｂに示された空間多重送信部４０６のウェイト生成部４２２と、図８Ａの優先度割付部４０４に通知される。
また、通信阻害が発生した場合、再送要求信号が受信側送信部４１７、アンテナ４１８、逆方向伝搬路４１９、アンテナ４２８、送信側受信部４２９を経て送信側再送制御部４３０に伝えられ、送信側再送制御部４３０は、通信阻害のあったデータを再送する。
このとき、逆方向伝搬路４１９は、ＦＤＤ方式では伝搬路４０８とは異なる周波数であり、ＴＤＤ方式では同一周波数である。
また、アンテナ４１８、４２８が空間多重アンテナで逆方向伝搬路４１９が空間多重伝搬路の場合もそうでない場合もある。
図８Ｅに示された空間多重送信部４０６は図８Ｂと既知信号挿入の位置が異なっている。
この例では、空間多重送信部４０６において、既知信号挿入部４３１は、空間ストリーム毎に符号化した信号に既知信号を挿入し、その後ウェイト乗算部４３２はウェイトを乗算し、変調部４３３はＣＤＭＡ、ＯＦＤＭなどの変調を行う。
これは優先度の低いデータがベストエフォートであり、優先度の高いデータが再送制御を必要とするギャランティの場合の例であり、優先度の高いデータのＱｏＳもベストエフォートの場合は、再送制御は行わない。その場合は、送信側再送制御部３３０、受信側３１８は不要であり、遅延時間は更に削減できる。
全てのデータがベストエフォートであっても、ベストエフォートの中で優先度の高いデータを優先度の高い空間ストリームに割り当てることによって優先度の高いデータが伝送し易くなるという効果が得られる。
これは、ベストエフォートの定義が、ベストエフォートとそれよりＱｏＳの低いバックグラウンドを含む場合、また、同じベストエフォートの中でもレベルと言われる更に細かい段階分けをする場合に相当する。
この実施例のように、送信側において伝搬路の予測頻度を減らし、受信側において伝搬路の予測を行わなくても、再送制御による遅延を削減できると言う効果を有している。
図９Ａ〜図９Ｄを参照して、更に他の実施例を説明する。ここでは、第１無線局５０１と第２無線局５０２は時分割複信方式（ＴＤＤ方式）で通信をしているものとする。
入力部５３０はカメラやマイクである。優先度付き符号化部５０３はスケーラブル符号化を行い、優先度付きデータを出力する。データ保持部５３１は再送のためのデータ保持を行う。優先度付きデータは、重要度に応じた優先度を設定された複数のデータ列で構成される。
優先度割付部５０４は、優先度付きデータの優先度の高いものから順次、優先度の高い空間ストリームに割り付ける。伝搬路予測優先度設定部５３３が空間ストリームの優先度を与える。その際、データ数が合わない時のデータ配分調整方法は、先に述べた優先度割付部３０４と同様である。
チャネル符号化部５０５は、空間ストリーム毎に割り振られたデータそれぞれに、受信側で誤りがないか検査できるようにチャネル符号化し、空間多重送信部５０６に送る。
空間多重送信部５０６では、図９Ｂに示された制御信号挿入部５４５が再送制御部５３２からの再送要求信号がある場合は再送要求信号を挿入する。無い場合は挿入しない。
ウェイト乗算部５２０では、伝搬路推定部５３４からの送信ウェイトを乗算し、既知信号挿入変調部５２１はウェイトを掛けた信号に既知信号を挿入し、方式によって、ＣＤＭＡもしくはＯＦＤＭＡ、ＯＦＤＭなどの変調を行い、必要に応じて無線搬送波周波数に周波数変換し、送信方向に切り替えられたアンテナ切り替え部５４３を通して、空間多重アンテナ５０７から空間多重伝搬路５０８に送信する。
ＴＤＤ方式では同じ周波数リソースを時間によって順方向と逆方向に切り替えて使うため、アンテナ切り替え部５４３及び５４４は、同じアンテナ５０７及び５０９に対して、時間により、空間多重送信部５０６、５１０からの入力と、空間多重受信部５２９、５１０への出力を切り替えて有効活用する。
空間多重アンテナ５０７は、複数アンテナ素子による構成と、単一アンテナの複数偏波を利用する構成方法がある。伝搬路は、空間多重伝搬路で、多重送信した複数のデータ列は、複数ストリームによって伝送され。また、伝搬損失やマルチパスやフェージング、シャドウイングが生じる。
第２無線局５０２は、空間多重アンテナ５０９で電波を受信する。このとき熱雑音が加わる。
アンテナ切り替え部５４４を通った信号は、図９Ｃに示された空間多重受信部５１０の復調部５２３に送られ、復調部５２３では、送信側の変調に合わせてＣＤＭＡ、ＯＦＤＭ等の復調を行い、必要に応じて信号処理可能な周波数に変換する。
ウェイト乗算部５２４では復調信号にウェイトを乗算し、制御信号分離部５４６では、再送要求信号を分離し、再送制御部５１６に伝える。
伝搬路推定部５１４では、図９Ｄに示された伝搬路計算部５２５で、送信側で挿入された既知信号もしくは疑似既知信号として扱うことのできる判定後信号を用い、復調信号に既知信号の複素共役を乗算して平均化して伝搬路計算値を得る。
更に、ウェイト生成部５２６は、伝搬路推定値から、ウェイトを計算する。ウェイトの計算方法は、Ｅ−ＳＤＭ、ＺＦ、ＭＭＳＥなどがある。
図９Ａの伝搬路予測優先度設定部５１５は、伝搬路計算値から空間ストリームの劣化しやすさを予測して優先度を決定する。劣化しやすさの予測は、先に説明した図（フローチャート）の方法がある。
最大固有値の空間ストリームは劣化しやすい空間ストリームであり、例えば、先の回の伝搬路計算値と比較して変化の大きい空間ストリーム等である。優先度の最も高い空間ストリームの復号が失敗すると通信阻害信号を出力し、成功すると通信阻害信号を出力しない。通信阻害信号は受信側再送制御部５１６に通知する。
再送制御部５１６は、通信阻害がなければ再送要求せず、通信阻害があると受信側送信部に再送要求信号を出力する。
優先度付き復号部５１２では、優先度付きチャネル符号部５３７において通信阻害信号の出力がないとき、優先度付きチャネル復号を行う。同一情報の優先度付きデータの場合、基本レイヤが通信できておらず拡張レイヤを復号しても無効なため、以降の復号を中断し、復号したデータのみを表示部５１３に送る。
優先度が最高の優先度付きデータが優先度の最も高い空間ストリームで終了せず、続く空間ストリームの復号が失敗した場合は、優先付きチャネル符号化部５３７が通信阻害信号を出力する。通信阻害がある場合は、復号処理を停止して再送データの受信を待つ。
優先度が最高の優先度付きデータは正しく復号でき優先度の低い優先度付きデータの復号に失敗した場合は、通信阻害信号は出力しない。
第２無線局５０２の表示部５１３は、画像の場合はディスプレイ、音声の場合はマイクなどである。
一方、通信阻害がある場合は、再送制御部５１６は再送要求信号を出力する。ＴＤＤ方式における逆方向の通信に割り当てられた時間において、再送要求信号は、図９Ｂに示された空間多重送信部５１７の制御信号挿入部５４５で送信信号に挿入される。
再送制御信号は、更に、図９Ｂに示されたウェイト乗算部５２０、既知信号挿入変調部５２１を通じて、送信方向に切り替えたアンテナ切り替え部５４４を通じて空間多重アンテナ５０９から、伝送路５０８を通して逆方向に伝搬され、第１基地局５０１の空間多重アンテナ５０７で受信され、逆方向に切り替えられたアンテナ切り替え部５４３を通って、空間多重受信部５２９で受信される。受信された後、再送制御信号は復調部５２３で復調され、ウェイト乗算部５２４でウェイトを掛けられたあと、制御信号分離部５４６から、再送制御部５３２に送られる。
再送制御部５３２は、データ保持部５３１に保持されている優先度情報付きデータを、再度、順方向の通信タイミングで再送する。
この場合、優先度割付部５０４を通じて優先度情報付きデータを再度空間ストリームに割り付け、優先度付きチャネル符号化部５０５、空間多重送信部５０６、送信方向に設定されたアンテナ切り替え部５４３を通して、空間多重伝搬路５０８を順方向に伝搬し、送信する。
第１無線局５０１からの優先度情報付きデータは、第２無線局５０２の空間多重アンテナ５０９で受信され、受信方向に切り替えられたアンテナ切り替え部５４４を通って空間多重受信部５１０を通り、優先度付きチャネル復号部５１１で復号される。この時、再送された信号の優先度の高い空間ストリームの信号が正しく復号できて通信阻害がないと、チャネル復号部は、チャネル復号信号を出力する。優先度付き復号部５１２は優先度付き復号した信号を出力し、表示部５１３は表示を行う。
逆方向の動作も同様である。第１無線局５０１と第２無線局５０２は同じ構成及び動作である。
第２無線局５０２の入力部５３６もカメラやマイクである。優先度付き符号化部５３７はスケーラブル符号化を行い、優先度付きデータを出力する。データ保持部５３１は再送のためのデータ保持を行う。優先度付きデータは、重要度に応じた優先度を設定された複数のデータ列で構成される。
優先度割付部５３８は、優先度付きデータの優先度の高いものから、順次、優先度の高い空間ストリームに割り付ける。
伝搬路予測優先度設定部５１５が空間ストリームの優先度を与える。その際、データ数が合わない時のデータ配分調整方法は、先に説明した方法と同様である。
チャネル符号化部５３９は、空間ストリーム毎に割り振られたデータそれぞれに、受信側で誤りがないか検査できるようにチャネル符号化し、空間多重送信部５１７に送る。
図９Ｂに示すように、第２無線局５０２の空間多重送信部５１７では、制御信号挿入部５４５で再送制御部５１６からの再送要求信号がある場合は再送要求信号を挿入し、ウェイト乗算部５２０では、伝搬路推定部５１４からの送信ウェイトを乗算し、既知信号挿入変調部５２１はウェイトを掛けた信号に既知信号を挿入し、方式によって、ＣＤＭＡもしくはＯＦＤＭＡ、ＯＦＤＭなどの変調を行い、必要に応じて無線搬送波周波数に周波数変換し、送信に切り替えたアンテナ切り替え部５４４を通して空間多重アンテナ５０９から送信し、空間多重伝搬路５０８を逆方向に伝搬する。
第１無線局５０１は、空間多重アンテナ５０７で電波を受信する。受信方向に切り替えたアンテナ切り替え部５４３を通った信号は、図９Ｃに示された空間多重受信部５２９の復調部５２３で復調され、必要に応じて信号処理可能な周波数に変換される。
続いて、空間多重受信部５２９のウェイト乗算部５２４では復調信号にウェイトを乗算し、制御信号分離部５４６では、再送要求信号がある場合は再送要求信号を分離して再送制御部５３２に出力し、再送要求信号が無い場合には、再送制御部５３２に出力しない。
伝搬路推定部５３４では、図９Ｄに示された伝搬路計算部５２５で、送信側で挿入された既知信号もしくは疑似既知信号として扱うことのできる判定後信号を用い、復調信号に既知信号の複素共役を乗算して平均化して伝搬路計算値を得る。ウェイト生成部５２６は、伝搬路推定値から、ウェイトを計算する。
伝搬路予測優先度設定部５３３は、伝搬路計算値から空間ストリームの劣化しやすさを予測して優先度を決定する。優先度の最も高い空間ストリームの復号が失敗すると通信阻害信号を出力し、成功すると通信阻害信号を出力しない。通信阻害信号は受信側再送制御部５３２に通知する。
再送制御部５３２は、通信阻害がなければ再送要求せず、通信阻害があると受信側送信部に再送要求信号を出力する。
優先度付き復号部５４１では、優先度付きチャネル符号部５０５において通信阻害信号の出力がないとき、優先度付きチャネル復号を行う。同一情報の優先度付きデータの場合、基本レイヤが通信できておらず拡張レイヤを復号しても無効なため、以降の復号を中断し、復号したデータのみを表示部５４２に送る。
優先度が最高の優先度付きデータが優先度の最も高い空間ストリームで終了せず、続く空間ストリームの復号が失敗した場合は、優先付きチャネル符号部が通信阻害信号を出力する。
通信阻害がある場合は、復号処理を停止して再送データの受信を待つ。
優先度が最高の優先度付きデータは正しく復号でき優先度の低い優先度付きデータの復号に失敗した場合は、第１無線局５０１は通信阻害信号を出力しない。表示部５４２は、画像の場合はディスプレイ、音声の場合はマイクなどである。通信阻害がある場合は、再送制御部５３２は、再送要求信号を出力する。
空間多重送信部５０６は、図９Ｂに示すように、順方向送信タイミングにおいて、制御信号挿入部５４５で再送要求信号を挿入する。更に、再送制御信号は、ウェイト乗算部５２０、既知信号挿入変調部５２１を通じて、送信方向に切り替えたアンテナ切り替え部５４３から空間多重アンテナ５０７を通じて伝送路５０８を順方向に伝搬する。伝搬された再送要求信号は、第２無線局５０２のアンテナ部５０９で受信され、受信側に切り替えたアンテナ切り替え部５４４を通って、空間多重受信部５１０で受信され、復調部５２３で復調され、ウェイト乗算部５２４でウェイトを掛けられたあと、制御信号分離部５４６から、再送制御部５３２に送られる。
逆方向送信タイミングにおいて、第２無線局５０２の再送制御部５１６は、優先度割付部５３８を通じて、データ保持部５４０の優先度情報付きデータを再送する。
優先度情報付きデータは優先度割付部５３８を通じて、再度、空間ストリームに割り付け、優先度付きチャネル符号化部５３９、空間多重送信部５１７、送信方向に切り替えられたアンテナ切り替え部５４４を通して、空間多重伝搬路５０８を逆方向に伝搬する。
第１無線局５０１では、優先度情報付きデータを空間多重アンテナ５０７で受信し、受信方向に切り替えられたアンテナ切り替え部５４３を通って空間多重受信部５２９を通り、優先度付きチャネル復号部５４０で復号される。この時、再送された信号の優先度の高い空間ストリームの信号が正しく復号できて通信阻害がないと、チャネル復号部は、チャネル復号信号を出力する。優先度付き復号部５４１は優先度付き復号後の信号を出力し、表示部５４２は表示を行う。
これは優先度の低いデータがベストエフォートであり、優先度の高いデータが再送制御を必要とするギャランティの場合の例であり、優先度の高いデータのＱｏＳもベストエフォートの場合は、再送制御は行わない。その場合は、再送制御部５３２，５３８は不要であり、遅延時間は更に削減できる。
全てのデータがベストエフォートであっても、ベストエフォートの中で優先度の高いデータを優先度の高い空間ストリームに割り当てることによって優先度の高いデータが伝送し易くなるという効果が得られる。
これは、ベストエフォートの定義が、ベストエフォートとそれよりＱｏＳの低いバックグラウンドを含む場合、また、同じベストエフォートの中でもレベルと言われる更に細かい段階分けをする場合に相当する。
図１０Ａ及び図１０Ｂを参照して、複数無線局を含むシステムに本発明を適用した場合の実施例を説明する。
図１０Ａでは、第１無線局６０１と第２無線局６０２、第３無線局６０３は空間多重通信をする。この方法はマルチユーザＭＩＭＯ、複数基地局協調ＭＩＭＯとして知られている。図１０Ａはこのようなシステムに本発明を適用した例である。
第１無線局６０１から第２無線局６０２、第３無線局６０３への伝搬を順方向と呼び、反対を逆方向という。前述した例と同様に、各無線局は送信時に既知信号を送信する。
受信側では既知信号もしくは疑似既知信号として用いることの出来る判定後信号を用いて、伝搬路特性を計算する。
第２無線局６０２、第３無線局６０３は伝搬路特性を第１無線局６０１に通知し、第１無線局６０１では、それぞれの伝搬路特性を組み合わせてウェイトを生成する。
図１０Ａの例において、第１無線局６０１の第ｊ送信アンテナと、第ｕ無線局の第ｋ受信アンテナ間の伝搬路特性をｈ_{（ｕ−１）×Ｋ＋ｋ，ｊ}とする。このときｕ＝２，３であり、Ｋは、第２無線局６０２と第３無線局６０３の受信アンテナ数である。このとき、伝搬路行列Ｈは以下に得る事が出来るため、ウェイト計算、固有値計算は１対１通信と同様に行える。

図１０Ｂは協調通信の例であり、優先度付き情報を第４無線局６０４と第５無線局６０５から、第６無線局６０６と第７無線局６０７に伝達する。この方法では、第４無線局６０４と第５無線局６０５、第６無線局６０６と第７無線局６０７はそれぞれ送信信号及び受信信号を共有する。
第ｌ無線局の第ｊ送信アンテナと、第ｕ無線局の第ｋ受信アンテナ間の伝搬路特性をｈ_{（ｕ−４）×Ｋ＋ｋ，（ｌ−６）×Ｌ＋ｊ}とする。このとき、ｌ＝４，５、ｕ＝６，７であり、Ｌは第４無線局、第５無線局の送信アンテナ数、Ｋは第６無線局、第７無線局の受信アンテナ数である。このとき、伝搬路行列Ｈは以下に得る事が出来るため、ウェイト計算、固有値計算は１対１通信と同様に行える。

送信側から複数の宛先へのデータがある場合、優先度には、各々の宛先毎の優先度を用いる必要があり、また、宛先のユーザの優先度情報も加味される。宛先の優先度の例としては、３ＧＰＰにおける端末のクラスなどがある。
このような複数局通信においても本発明は適用できる。すなわち、２以上の複数局間の空間ストリームにおいても、これまで述べた２局間の空間ストリームのように優先度を付けて、優先度付きデータの優先度に応じて割り付け通信する事ができる。Next, specific examples of the communication system according to each embodiment will be described.
Returning to FIG. 4, there is shown a flowchart for specifically explaining a method for predicting degradation of E-SDM used in the embodiment shown in FIGS. 1 and 2. Here, the flowchart shown in FIG. 1 is shown. The operation of the propagation path prediction priority setting unit 105 is shown. The channel prediction priority setting unit 105 and the priority assignment unit 101 may be realized by hardware or a software program. The software program may be stored in a computer-readable recording medium.
In FIG. 4, when propagation path calculation value hkj is input (step S1), propagation path calculation value hkj is arranged to create propagation path matrix H (step S2), eigenvalue calculation is performed, eigenvalue number m and eigenvalue are calculated. λi (i = 1, 2,..., m) is calculated (step S3). Examples of eigenvalue calculation methods include singular value decomposition, Householder, QR decomposition, and DB method.
The priority PSi of the i-th spatial stream is initialized (step S4).
PSi = 1 (i = 1, 2,..., M) Equation 29
If the value of m is 1 or less, the priority is invalid and the process is terminated (step S5). When m is 2 or less (step S6), the maximum eigenvalue λmax is obtained (step S7), and the priority PSmax of the related spatial stream is lowered (step S8).
PSmax = 2 Equation 30
Here, the priority of the spatial stream is highest at 1, and the higher the value, the lower the priority. This is because the spatial stream having the maximum eigenvalue tends to deteriorate with time. This is because the maximum power is allocated to the stream with the maximum eigenvalue, and interference due to time change is larger than that of other spatial streams (see Non-Patent Document 9).
When the value of m is larger than 2 (step S6), the maximum eigenvalue λmax and the minimum eigenvalue λmin are obtained (step S9), and the priorities PSmax and PSmin of the related spatial stream are lowered (step S10).
PSmin = 2 Formula 31
This is because the minimum eigenvalue is likely to be lost even if there is a slight fluctuation, and thus there is a high possibility of communication error.
Table 1 shows an example of priority setting when m = 2. Since the maximum eigenvalue λmax = 4 and i = 1 at this time, PS1 = 2.

Table 2 shows an example of priority setting when m = 4. Since the maximum eigenvalue λmax = 9 and i = 2 at this time, PS2 = 2 and λmin = 0.25, and at this time i = 1, PS2 = 2, and the spatial stream of the maximum eigenvalue and the spatial stream of the minimum eigenvalue Decrease the priority.

Also, propagation path matrix creation (step S3) and eigenvalue calculation (step S4) can be shared with the reception side transmission multiplexing unit or the transmission side transmission multiplexing unit.
Based on the flowchart of FIG. 5, a method for predicting degradation of E-SDM during repeated communication will be described. The term “during repeated communication” here means, for example, data communication over a plurality of packets. This is a specific example of FIG. 2, and is an operation of the propagation path prediction priority setting unit 105 of FIG.
During repeated communication, the stability of each spatial stream is predicted from the eigenvalue calculated from the previous propagation path calculation value, the eigenvector calculated from the current propagation path calculation value, the eigenvalue calculated from the current propagation path calculation, and the eigenvector change. This is a method of increasing the priority and decreasing the priority of the unstable spatial stream.
First, the previous eigenvector eu (n−1) (i = 1, 2,... M, u = 1, 2,..., M (n−1)) is held (step S11). Here, m (n−1) is the number of previous eigenvalues.
When the nth propagation path calculation value hkj (n) is input (step S12), the propagation path prediction priority setting unit 105 arranges the propagation path calculation value hkj (n) and sets the propagation path matrix H (n ) (Step S13), eigenvector calculation is performed, and the number of eigenvalues m and eigenvectors ei (i = 1, 2,..., M) are determined (step S14). Eigenvector calculation methods include singular value decomposition, Householder, QR decomposition, DB method, and the like. The length of each eigenvector ei is the number of transmitting antennas M for the transmitting side eigenvector, and the number of receiving side antennas N when performing with the receiving side eigenvector. Since either can be used for the degradation prediction, in this description, the eigenvector correlation amount is calculated in both cases, and the maximum eigenvector correlation amount is selected for each spatial stream, so that the previous spatial stream number u and the current time are selected. Is associated with the unique stream number i.

Where e _i (N), e _u (N-1) is a normalized value. That means

Δe for each i _iu Is selected, and u at that time is set to i (n-1) (step S16).
Further, a threshold value ΔethL is determined, and Δe _{ii (n-1)} Is lower than the threshold value ΔethL (step S18), it is determined that the previous i (n−1) spatial stream and the current i th spatial stream are not continuous spatial streams, and the i th spatial stream is unstable. It is determined that there is a lower priority (step S19).
PSi = 3 Formula 35
Further, a threshold value ΔethH is determined, and Δe _{ii (n-1)} Is higher than the threshold value ΔethH (step S20), it is determined that the correlation between the previous eigenvector and the current eigenvector is sufficiently high, and a high priority is set (step S21).
PSi = 1 Formula 36
Δe _{ii (n-1)} Is Δe _thL <Δe _{ii (n-1)} <Δe _thH The medium stream is set to a medium priority.
PSi = 2 Formula 37
This is performed for all spatial streams from i = 1 to m (steps S17 and S23).
The maximum eigenvalue λmax is obtained (step S24), and the priority PSmax of the associated spatial stream is lowered (step S25).
This is because the maximum eigenvalue is likely to deteriorate, and although not specifically described, the inter-stream interference power due to the deterioration of correlation increases in order to allocate the maximum transmission power (see Non-Patent Document 3).
Based on the flowchart of FIG. 6, a W-SDM degradation prediction method during repeated communication, which is a specific example of FIG. 2, will be described.
This is the operation of the propagation path prediction priority setting unit 205 in FIG.
Since W-SDM only performs transmission power control and adaptive modulation based on propagation path characteristics, the spatial stream is for each transmission antenna, and the spatial stream number i is considered to be equal to the antenna number j.
The propagation path calculation value hjk (n-1) calculated at the previous time is held (step S26). The propagation path calculation value hjk (n) calculated this time is input (step 27). The propagation path change amount Δhj (n) of the antenna j is calculated (step S28). However, this equation is used when the propagation path calculation value is not a standardized value.

The amount of change in the propagation path of each antenna is compared, and the higher priority is set in order from the antenna with the larger value (step S29).
In particular, if Δhj (n) is a negative value, it indicates that the image has been reduced, so that it is predicted to deteriorate, and a low priority is set.
A specific example is shown in Table 3. The priority of the spatial stream number 3 with the largest propagation path change amount Δhj (n) is set to 1 as the maximum, and then the priority is set in the order of the spatial numbers 2, 1, and 4 in order of decreasing. .

As an example of the operation of the propagation path prediction priority setting unit 105 in FIG. 1 and the specific example of FIG. 2 in the repeated communication, the previous eigenvalue obtained from the propagation path calculation value calculated in the previous round, The current eigenvalue obtained from the propagation path calculated value is compared, and the spatial stream related to the eigenvalue that has changed greatly is predicted to be more likely to deteriorate than the spatial stream of the eigenvalue that does not change so much, and the priority is set low.
In addition, various methods can be used for assigning the priority of the spatial stream, such as predicting that the spatial stream related to the reduced eigenvalue is deteriorated and setting the priority low.
Another embodiment according to the present invention will be described with reference to FIGS. 7A to 7E.
Here, an example in which data with priority is transmitted from a specific transmission side 301 to the reception side radio station 302 is shown. The data with priority is assumed to be composed of a plurality of data strings having different priorities.
The propagation path prediction priority setting unit 305 predicts the ease of deterioration of each spatial stream from the propagation path calculation value, and assigns a low priority to the one that is difficult to deteriorate and that is easy to deteriorate.
The priority assigning unit 304 assigns the data with priority to the spatial streams with the highest priority in order from the data with the highest priority. If the number of data does not match at the time of allocation, the data distribution is adjusted. The propagation path prediction priority setting unit 305 and the priority assignment unit 304 described above may be realized by hardware as in the above-described embodiment, or may be realized by a software program.
This will be specifically described below using a table.
Tables 4 and 5 show examples of the data with priority and the number of bits, the priority of the spatial stream, and the number of transmission bits.
Prioritized data is based on spatial scalability, temporal scalability, SNR scalability, ROI scalability, etc. as described in the background art of this specification, and when video and audio are delivered simultaneously Suppose that the priority of audio is higher than that of images. There is also a composite of these scalability and data types. Although how to express the priority differs depending on the system, in this example, a high priority is represented by a small number.
According to Table 4, there are a basic layer with the lowest resolution, and a first enhancement layer and a second enhancement layer of redundant data that increase the resolution sequentially. The priority is the highest in the base layer according to the importance of the information, and is set to 1. The lower the quality of service (QoS), the higher the priority. On the other hand, the propagation path prediction priority setting unit 305 sets the priority of the i-th spatial stream.
The number of transmission bits is specified by the propagation path information. Table 5 is an example.
The priority assigning unit 304 assigns the priority level 1 basic layer to the priority 1 second spatial stream because the priority assignment unit 304 sequentially assigns the highest priority data to the spatial stream with the highest priority.
Since the number of data in the data string is different, a total of 384 bits of 256 bits in the first half of the redundant data of the first enhancement layer is allocated to the second spatial stream following the 128 bits of the base layer. Subsequently, the remaining 126 bits of the redundant data of the first enhancement layer are allocated to the third spatial stream of priority 2, and then the redundant data of the second enhancement layer is assigned to the first spatial stream of priority 3 and 4 and the fourth Allocated to the spatial stream.
Thus, the priority assignment unit 304 may have a data adjustment function.

The channel coding unit 302 shown in FIGS. 7A to 7E performs channel coding so that the data allocated to each spatial stream can be checked for errors on the receiving side, and sends the data to the spatial multiplexing transmission unit 306.
As shown in FIG. 7B, the spatial multiplexing transmission unit 306 includes a weight multiplication unit 320, a known signal insertion modulation unit 321, and a weight generation unit 322. The weight generation unit 322 sets the transmission weight Wt of M × m from the propagation path information, and the channel multiplication data bi (i = 1, 2,..., M) transmitted by the weight multiplication unit 320 in each spatial stream. The antenna transmission signal ti (i = 1, 2,..., M) is multiplied by the transmission weight.

The known signal insertion modulation unit 321 inserts a known signal into the signal multiplied by the weight, performs modulation such as CDMA or OFDMA according to a method, converts the frequency to a radio carrier frequency as necessary, and transmits a space from the transmission spatial multiplexing antenna 307 It transmits to the multiple propagation path 308.
The transmission spatial multiplexing antenna 307 includes a configuration using a plurality of antenna elements and a configuration method using a plurality of polarizations of a single antenna.
A plurality of data strings multiplexed and transmitted on the spatial multiplexing propagation path 308 are transmitted by a plurality of streams. On the spatial multiplexing propagation path 308, propagation loss, multipath, fading, shadowing, and the like occur.
On the reception side 302, radio waves are received by the spatial multiplexing receiver 310 via the reception spatial multiplexing antenna 309. Thermal noise is also added when receiving.
As shown in FIG. 7C, the spatial multiplexing receiver 310 includes a demodulator 323 and a weight multiplier 324. The demodulator 323 performs demodulation such as CDMA and OFDM in accordance with the modulation on the transmission side. If necessary, the frequency is converted to a signal-processable frequency. On the other hand, weight multiplying section 324 of spatial multiplexing receiving section 310 multiplies the demodulated signal by a weight.
The propagation path estimation unit 314 of the reception-side wireless station 302 includes a propagation path calculation unit 325, a weight generation unit 326, and a propagation path information generation unit 327 as illustrated in FIG. 7D. The propagation path calculation unit 325 of the propagation path estimation unit 314 uses a post-determination signal that can be treated as a known signal or a pseudo known signal inserted on the transmission side, and multiplies the demodulated signal by the complex conjugate of the known signal and averages it. Then, a propagation path calculation value is obtained and output to the weight generation unit 326 as a propagation path estimation value. The weight generation unit 326 calculates a weight from the propagation path estimation value. The weight calculation method includes E-SDM, ZF, MMSE, and the like.
The propagation path information generation unit 327 of the propagation path estimation unit 314 selects and outputs the propagation path information to be sent to the transmission side based on the propagation path calculation value or weight based on the value decided by the system.
The propagation path information is a designation of the communication capacity and transmission side weight for each spatial stream calculated from the propagation path calculation value and noise. As a conventional example of the propagation path information, a CQI (Channel Quality Indicator) that displays a communication rate, There are PCI (Precoding Control Indicator) and Codebook Index that notify the weight.
The priority is determined by predicting the ease of degradation of the spatial stream from the propagation path information. The ease of degradation is that a spatial stream multiplied by the maximum weight is likely to be degraded, and a spatial stream having a large change in capacity and weight setting as compared with the previous propagation path information is likely to be degraded.
The channel decoding unit 311 with priority shown in FIG. 7A performs channel decoding for each spatial stream according to the priority of the spatial stream. If decoding of the spatial stream with the highest priority fails, a communication inhibition signal is output, and if successful, no communication inhibition signal is output. The communication inhibition signal is notified to the reception side retransmission control unit 316.
The reception side retransmission control unit 316 does not request retransmission when there is no communication inhibition, and outputs a retransmission request signal to the reception side transmission unit when there is communication inhibition.
The priority decoding unit 312 performs priority channel decoding when the priority channel decoding unit 311 does not output a communication inhibition signal. In the case of data with priority of the same information, since the base layer cannot communicate and it is invalid to decode the enhancement layer, the subsequent decoding is interrupted and only the decoded data is sent to the display unit 313.
If the priority-priority data with the highest priority does not end with the highest-priority spatial stream and decoding of the subsequent spatial stream fails, the prioritized channel decoding unit 312 outputs a communication inhibition signal. If there is communication obstruction, the decoding process is stopped and reception of retransmission data is awaited.
If the data with priority with the highest priority can be decoded correctly and decoding of the data with priority with a low priority fails, the communication inhibition signal is not output. The display unit 313 is a display in the case of an image and a microphone in the case of sound.
The propagation path information from the reception-side radio station 302 is received by the antenna 328 through the antenna 318 and the reverse propagation path 319, received by the transmission-side reception unit 329, and the weight generation unit 322 of the spatial multiplexing transmission unit 306 and the propagation path The prediction priority setting unit 305 is notified.
Also, when communication obstruction occurs, a retransmission request signal is transmitted to the transmission side retransmission control unit 330 via the reception side transmission unit 317, antenna 318, reverse propagation path 319, antenna 328, transmission side reception unit 329, and transmission side The retransmission control unit retransmits data that has been blocked in communication.
At this time, the reverse propagation path 319 has a frequency different from that of the propagation path 308 in the FDD system and the same frequency in the TDD system.
The antennas 318 and 327 may be spatially multiplexed antennas and the reverse propagation path 319 may or may not be a spatially multiplexed path.
FIG. 7E illustrates an example of a spatial multiplexing transmission unit 306 having a configuration different from that of the spatial multiplexing transmission unit 306 illustrated in FIG. 7B. The spatial multiplexing transmission unit 306 shown in FIG. 7E includes a known signal insertion unit 331, a weight multiplication unit 332, and a modulation unit 333, and has a weight generation unit 322 as in FIG. 7B. As is clear from FIG. 7E, this is an example in which the insertion position of the known signal inserted by the known signal insertion unit 331 is different.
In the example shown in FIG. 7E, the known signal insertion unit 331 provided in the spatial multiplexing transmission unit 306 inserts a known signal into the signal encoded for each spatial stream, and then the weight multiplication unit 332 multiplies the weight. Then, the modulation unit 333 performs modulation such as CDMA and OFDM.
In this example, low-priority data is a background or best effort that does not guarantee reliable transmission, and will be referred to as best effort here as a representative. Also, high priority data is data that guarantees reliable transmission, and is referred to as guarantee.
On the other hand, in the case of the best effort of the type in which the QoS of the low priority data does not guarantee the transmission of the QoS of the high priority data in the background,
No retransmission control is performed. In that case, the transmission side control unit 330 and the reception side transmission unit 317 are unnecessary, and the delay time can be further reduced. Even if all the data is best effort, it is possible to easily transmit high priority data by assigning a date having a high priority in the best effort to a spatial stream having a high priority.
This corresponds to a case where the definition of best effort includes a best effort and a background with a lower QoS than that, and a case where a finer division called a level is performed within the same best effort.
The effect of this embodiment is that the delay due to retransmission control can be reduced even if the propagation path estimation frequency on the transmission side is reduced. The reason for this is that errors can be biased to low priority data with priority, in order to allocate high priority data to spatial streams that are not easily degraded by changes in channel characteristics over time. This is because data with high priority can be communicated correctly and retransmission control is not performed.
Another embodiment according to the present invention will be described with reference to FIGS. 8A to 8E.
The illustrated embodiment is an example in which data with priority is communicated from a specific transmitting radio station 401 to a receiving radio station 402. The data with priority is composed of a plurality of data strings in which priorities according to importance are set. The priority assigning unit 404 assigns the priority-added data to the spatial stream with the highest priority in order from the data with the highest priority. The priority information of the spatial stream is given by the propagation path information with priority. At this time, the data distribution adjustment method when the number of data does not match is performed in the same manner as the priority assignment unit 304 shown in FIG. 7A.
Channel coding section 405 performs channel coding so that each of the data allocated to each spatial stream can be checked for errors on the receiving side, and sends the data to modulated spatial multiplexing transmission section 406.
In spatial multiplexing transmission section 406, as shown in FIG. 8B, the weight generation section 422 sets m × m transmission weights Wt from the prioritized propagation path information, and the weight multiplication section 420 transmits the respective spatial streams. The encoded data bi (i = 1, 2,..., M) is multiplied by a transmission weight to obtain an antenna transmission signal ti (i = 1, 2,..., M).
The detailed operation is the same as that of the spatial multiplexing transmitter 306 shown in FIGS. 7A to 7E.
That is, as shown in FIG. 8B, the known signal insertion modulation unit 421 of the spatial multiplexing transmission unit 406 inserts a known signal into the weighted signal, performs modulation such as CDMA or OFDMA depending on the system, and if necessary The frequency is converted to a radio carrier frequency and transmitted from the transmission spatial multiplexing antenna 407 to the spatial multiplexing propagation path 408.
The transmission spatial multiplexing antenna 407 includes a configuration using a plurality of antenna elements and a configuration method using a plurality of polarized waves of a single antenna.
A plurality of data strings multiplexed and transmitted on the spatial multiplexing propagation path 408 are transmitted by a plurality of streams. In the spatial multiplexing channel 408, propagation loss, multipath, fading, shadowing, etc. occur, and the characteristics of the spatial multiplexing channel 408 change with time.
The reception-side radio station 402 receives radio waves with the reception spatial multiplexing antenna 409.
At this time, thermal noise is added. As shown in FIG. 8C, the demodulator 423 of the spatial multiplexing receiver 410 performs demodulation such as CDMA and OFDM in accordance with the modulation on the transmission side, and converts it to a frequency that can be signal processed as necessary. A weight multiplier 424 multiplies the demodulated signal by a weight.
Next, in the propagation path estimation unit 414 shown in FIG. 8D, the propagation path calculation unit 425 uses a post-determination signal that can be treated as a known signal or a pseudo known signal inserted on the transmission side, and is known as a demodulated signal. Multiply the complex conjugates of the signals and average them to obtain the calculated propagation path.
Furthermore, the weight generation unit 426 of the propagation path estimation unit 414 illustrated in FIG. 8D calculates a weight from the propagation path estimation value. The weight calculation method includes E-SDM, ZF, MMSE, and the like.
The priority-added propagation path information generation unit 427 selects propagation path information to be sent to the transmission side based on the propagation path calculation value or weight from the values decided by the system. In addition, the spatial stream priority information received from the propagation path prediction priority setting unit 415 is combined to output the propagation path information with priority.
The propagation path information is designation of the communication capacity and the transmission side weight for each spatial stream calculated from the propagation path calculation value and noise, and conventional examples of the propagation path information include CQI and PCI.
At this time, assuming that the number of bits of the propagation path information is f bits, the priority propagation path characteristics add priority information g bits to the propagation path information f bits.
For example, when the number of spatial streams is m = 4, if the spatial stream number with the highest priority is added as priority information, it can be notified with 2 bits, so g = 2 bits are added. When the propagation path information is 6 bits, 2 bits of priority information are added to the propagation path information, and notification is made with 8 bits.
The propagation path prediction priority setting unit 415 shown in FIG. 8A determines the priority by predicting the ease of degradation of the spatial stream from the propagation path calculation value. As a method of predicting the ease of deterioration, there is the method described above with reference to FIGS. 7A to 7E and FIG.
Furthermore, predicting the ease of degradation by utilizing the fact that the spatial stream multiplied by the maximum weight is likely to be degraded, and that the spatial stream with a large change in capacity and weight setting is more likely to degrade than the previous propagation path information. You may do it.
The channel decoding unit with priority 411 performs channel decoding for each spatial stream according to the priority of the spatial stream. If decoding of the spatial stream with the highest priority fails, a communication inhibition signal is output, and if successful, no communication inhibition signal is output. The communication inhibition signal is notified to the reception side retransmission control unit 416.
The reception side retransmission control unit 416 does not request retransmission if there is no communication inhibition, and outputs a retransmission request signal to the reception side transmission unit when there is communication inhibition.
The priority decoding unit 412 performs priority channel decoding when the priority channel decoding unit 411 does not output a communication inhibition signal. In the case of data with priority of the same information, since the base layer cannot communicate and it is invalid to decode the enhancement layer, the subsequent decoding is interrupted and only the decoded data is sent to the display unit 413.
If the priority-priority data with the highest priority does not end with the highest-priority spatial stream and decoding of the subsequent spatial stream fails, the prioritized channel decoding unit 412 outputs a communication inhibition signal. If there is communication obstruction, the decoding process is stopped and reception of retransmission data is awaited.
If the data with priority with the highest priority can be decoded correctly and decoding of the data with priority with a low priority fails, the communication inhibition signal is not output. The display unit 413 is a display in the case of an image and a microphone in the case of sound.
In the illustrated example, the propagation path information is received by the antenna 428 through the antenna 418 and the reverse propagation path 419, received by the transmission-side reception unit 429, and the weight generation unit of the spatial multiplexing transmission unit 406 illustrated in FIG. 8B. 422 and the priority assignment unit 404 in FIG. 8A.
Also, when communication obstruction occurs, a retransmission request signal is transmitted to the transmission side retransmission control unit 430 via the reception side transmission unit 417, antenna 418, reverse propagation path 419, antenna 428, transmission side reception unit 429, and transmission side The retransmission control unit 430 retransmits data that has been subjected to communication obstruction.
At this time, the reverse propagation path 419 has a different frequency from the propagation path 408 in the FDD system, and the same frequency in the TDD system.
The antennas 418 and 428 may be spatially multiplexed antennas, and the reverse propagation path 419 may or may not be a spatially multiplexed propagation path.
The spatial multiplexing transmitter 406 shown in FIG. 8E is different from FIG. 8B in the position of known signal insertion.
In this example, in the spatial multiplexing transmission unit 406, the known signal insertion unit 431 inserts a known signal into the signal encoded for each spatial stream, then the weight multiplication unit 432 multiplies the weight, and the modulation unit 433 performs CDMA, Performs modulation such as OFDM.
This is an example of a case where the low priority data is the best effort, and the high priority data is a guarantee requiring retransmission control. When the QoS of the high priority data is also the best effort, the retransmission control is performed. Not performed. In that case, the transmission side retransmission control unit 330 and the reception side 318 are unnecessary, and the delay time can be further reduced.
Even if all the data is the best effort, it is possible to easily transmit the high-priority data by assigning the high-priority data in the best effort to the high-priority spatial stream.
This corresponds to a case where the definition of best effort includes a best effort and a background with a lower QoS than that, and a case where a finer division called a level is performed within the same best effort.
As in this embodiment, there is an effect that the delay due to retransmission control can be reduced without reducing the prediction frequency of the propagation path on the transmission side and performing the prediction of the propagation path on the reception side.
Still another embodiment will be described with reference to FIGS. 9A to 9D. Here, it is assumed that the first wireless station 501 and the second wireless station 502 are communicating by a time division duplex method (TDD method).
The input unit 530 is a camera or a microphone. The coding unit with priority 503 performs scalable coding and outputs data with priority. The data holding unit 531 holds data for retransmission. The data with priority is composed of a plurality of data strings in which priorities according to importance are set.
The priority assigning unit 504 assigns the data with priority to the spatial stream with the highest priority in order from the data with the highest priority. The propagation path prediction priority setting unit 533 gives the priority of the spatial stream. At this time, the data distribution adjustment method when the number of data does not match is the same as that of the priority assignment unit 304 described above.
The channel coding unit 505 performs channel coding so that the data allocated to each spatial stream can be checked for errors on the receiving side, and sends the data to the spatial multiplexing transmission unit 506.
In spatial multiplexing transmission section 506, control signal insertion section 545 shown in FIG. 9B inserts a retransmission request signal when there is a retransmission request signal from retransmission control section 532. If not, do not insert.
Weight multiplication section 520 multiplies the transmission weight from propagation path estimation section 534, and known signal insertion modulation section 521 inserts a known signal into the signal multiplied by the weight, and performs modulation such as CDMA, OFDMA, or OFDM depending on the method. The frequency is converted to a radio carrier frequency as necessary, and transmitted from the spatial multiplexing antenna 507 to the spatial multiplexing propagation path 508 through the antenna switching unit 543 switched in the transmission direction.
In the TDD scheme, the same frequency resource is used by switching between the forward direction and the reverse direction according to time, so that the antenna switching units 543 and 544 input to the same antennas 507 and 509 from the spatial multiplexing transmission units 506 and 510 depending on time Then, the output to the spatial multiplexing receivers 529 and 510 is switched for effective use.
The spatial multiplexing antenna 507 includes a configuration using a plurality of antenna elements and a configuration method using a plurality of polarized waves of a single antenna. The propagation path is a spatial multiplex propagation path, and a plurality of multiplexed data strings are transmitted by a plurality of streams. Further, propagation loss, multipath, fading, and shadowing occur.
Second radio station 502 receives radio waves with spatial multiplexing antenna 509. At this time, thermal noise is added.
The signal that has passed through the antenna switching unit 544 is sent to the demodulation unit 523 of the spatial multiplexing receiver 510 shown in FIG. 9C, and the demodulation unit 523 performs demodulation such as CDMA and OFDM in accordance with the modulation on the transmission side, If necessary, the frequency is converted to a signal-processable frequency.
Weight multiplication section 524 multiplies the demodulated signal by a weight, and control signal separation section 546 separates the retransmission request signal and transmits it to retransmission control section 516.
The propagation path estimation unit 514 uses a post-determination signal that can be handled as a known signal or a pseudo known signal inserted on the transmission side by the propagation path calculation unit 525 shown in FIG. Multiply conjugates and average to obtain propagation path calculation values.
Furthermore, the weight generation unit 526 calculates a weight from the propagation path estimation value. The weight calculation method includes E-SDM, ZF, MMSE, and the like.
The propagation path prediction priority setting unit 515 in FIG. 9A determines the priority by predicting the ease of degradation of the spatial stream from the propagation path calculation value. There is a method of the figure (flow chart) described above for predicting the ease of deterioration.
The spatial stream with the largest eigenvalue is a spatial stream that is likely to deteriorate, for example, a spatial stream with a large change compared to the previous propagation path calculation value. If decoding of the spatial stream with the highest priority fails, a communication inhibition signal is output, and if successful, no communication inhibition signal is output. The communication inhibition signal is notified to the reception side retransmission control unit 516.
If there is no communication inhibition, retransmission control section 516 does not request retransmission, and if there is communication inhibition, it outputs a retransmission request signal to the receiving side transmission section.
The priority decoding unit 512 performs channel decoding with priority when there is no communication inhibition signal output in the channel coding unit 537 with priority. In the case of data with priority of the same information, since the base layer cannot communicate and it is invalid to decode the enhancement layer, the subsequent decoding is interrupted and only the decoded data is sent to the display unit 513.
If the priority-priority data with the highest priority does not end with the highest-priority spatial stream and decoding of the subsequent spatial stream fails, the prioritized channel encoding unit 537 outputs a communication inhibition signal. If there is communication obstruction, the decoding process is stopped and reception of retransmission data is awaited.
If the data with priority with the highest priority can be decoded correctly and decoding of the data with priority with a low priority fails, the communication inhibition signal is not output.
The display unit 513 of the second wireless station 502 is a display in the case of an image and a microphone in the case of sound.
On the other hand, when there is communication obstruction, retransmission control section 516 outputs a retransmission request signal. The retransmission request signal is inserted into the transmission signal by the control signal insertion unit 545 of the spatial multiplexing transmission unit 517 shown in FIG. 9B at the time allocated to the reverse communication in the TDD scheme.
The retransmission control signal further propagates in the reverse direction from the spatial multiplexing antenna 509 through the transmission line 508 through the antenna switching unit 544 switched to the transmission direction through the weight multiplication unit 520 and the known signal insertion modulation unit 521 shown in FIG. 9B. Then, the signal is received by the spatial multiplexing receiver 529 through the antenna switching unit 543 that is received by the spatial multiplexing antenna 507 of the first base station 501 and switched in the reverse direction. After being received, the retransmission control signal is demodulated by the demodulation unit 523, multiplied by the weight by the weight multiplication unit 524, and then sent from the control signal separation unit 546 to the retransmission control unit 532.
The retransmission control unit 532 retransmits the data with priority information held in the data holding unit 531 again at the forward communication timing.
In this case, data with priority information is assigned again to the spatial stream through the priority assigning unit 504, and spatial multiplexing is performed through the channel encoder with priority 505, the spatial multiplexing transmission unit 506, and the antenna switching unit 543 set in the transmission direction. It propagates along the propagation path 508 in the forward direction and transmits.
Data with priority information from the first radio station 501 is received by the spatial multiplexing antenna 509 of the second radio station 502, passes through the antenna switching unit 544 switched in the reception direction, passes through the spatial multiplexing reception unit 510, and is prioritized. Decoded by the channel decoding unit 511 with degrees. At this time, if the signal of the spatial stream with high priority of the retransmitted signal can be correctly decoded and there is no communication hindrance, the channel decoding unit outputs a channel decoded signal. The decoding unit with priority 512 outputs the decoded signal with priority, and the display unit 513 performs display.
The operation in the reverse direction is the same. The first radio station 501 and the second radio station 502 have the same configuration and operation.
The input unit 536 of the second wireless station 502 is also a camera or a microphone. The encoding unit with priority 537 performs scalable encoding and outputs data with priority. The data holding unit 531 holds data for retransmission. The data with priority is composed of a plurality of data strings in which priorities according to importance are set.
The priority assigning unit 538 assigns the data with priority to the spatial stream with the highest priority in order from the data with the highest priority.
The propagation path prediction priority setting unit 515 gives the priority of the spatial stream. At this time, the data distribution adjustment method when the number of data does not match is the same as the method described above.
The channel coding unit 539 performs channel coding so that each of the data allocated to each spatial stream can be checked for errors on the receiving side, and sends the data to the spatial multiplexing transmission unit 517.
As shown in FIG. 9B, in the spatial multiplexing transmission section 517 of the second radio station 502, when there is a retransmission request signal from the retransmission control section 516 in the control signal insertion section 545, a retransmission request signal is inserted, and a weight multiplication section 520 Then, the transmission weight from the propagation path estimation unit 514 is multiplied, and the known signal insertion modulation unit 521 inserts a known signal into the weighted signal, and performs modulation such as CDMA, OFDMA, OFDM, etc. depending on the method. Accordingly, the frequency is converted into a radio carrier frequency, and transmitted from the spatial multiplexing antenna 509 through the antenna switching unit 544 switched to transmission, and propagates in the spatial multiplexing propagation path 508 in the reverse direction.
The first radio station 501 receives radio waves with the spatial multiplexing antenna 507. The signal passing through the antenna switching unit 543 switched to the reception direction is demodulated by the demodulating unit 523 of the spatial multiplexing receiving unit 529 shown in FIG. 9C, and converted to a signal-processable frequency as necessary.
Subsequently, weight multiplying section 524 of spatial multiplexing receiving section 529 multiplies the demodulated signal by a weight, and control signal demultiplexing section 546 demultiplexes the retransmission request signal and outputs it to retransmission control section 532 if there is a retransmission request signal. If there is no retransmission request signal, it is not output to the retransmission control unit 532.
The propagation path estimation unit 534 uses a post-determination signal that can be treated as a known signal or a pseudo known signal inserted on the transmission side by the propagation path calculation unit 525 shown in FIG. Multiply conjugates and average to obtain propagation path calculation values. The weight generation unit 526 calculates a weight from the propagation path estimation value.
The propagation path prediction priority setting unit 533 predicts the ease of degradation of the spatial stream from the propagation path calculation value and determines the priority. If decoding of the spatial stream with the highest priority fails, a communication inhibition signal is output, and if successful, no communication inhibition signal is output. The communication inhibition signal is notified to the reception side retransmission control unit 532.
If there is no communication inhibition, retransmission control section 532 does not request retransmission, and if there is communication inhibition, it outputs a retransmission request signal to the receiving side transmission section.
The priority decoding unit 541 performs priority channel decoding when the priority channel encoder 505 does not output a communication inhibition signal. In the case of data with priority of the same information, since the base layer cannot communicate and it is invalid to decode the enhancement layer, subsequent decoding is interrupted and only the decoded data is sent to the display unit 542.
When the priority-added data with the highest priority does not end with the highest-priority spatial stream and decoding of the subsequent spatial stream fails, the prioritized channel encoding unit outputs a communication inhibition signal.
If there is communication obstruction, the decoding process is stopped and reception of retransmission data is awaited.
If the priority-added data with the highest priority can be correctly decoded and decoding of the priority-added data with a low priority fails, the first wireless station 501 does not output a communication inhibition signal. The display unit 542 is a display in the case of an image and a microphone in the case of sound. If there is communication obstruction, the retransmission control unit 532 outputs a retransmission request signal.
As shown in FIG. 9B, spatial multiplexing transmission section 506 inserts a retransmission request signal at control signal insertion section 545 at the forward transmission timing. Further, the retransmission control signal propagates in the forward direction through the weight multiplication unit 520 and the known signal insertion modulation unit 521 from the antenna switching unit 543 switched to the transmission direction through the spatial multiplexing antenna 507 in the forward direction. The propagated retransmission request signal is received by the antenna unit 509 of the second radio station 502, passed through the antenna switching unit 544 switched to the receiving side, received by the spatial multiplexing receiver 510, demodulated by the demodulator 523, After being multiplied by the weight multiplication unit 524, it is sent from the control signal separation unit 546 to the retransmission control unit 532.
At the reverse transmission timing, the retransmission control unit 516 of the second radio station 502 retransmits the data with priority information of the data holding unit 540 through the priority assignment unit 538.
The data with priority information is assigned to the spatial stream again through the priority assignment unit 538, and is transmitted to the spatial stream through the channel coding unit 539 with priority, the spatial multiplexing transmission unit 517, and the antenna switching unit 544 switched in the transmission direction. Propagates along the path 508 in the opposite direction.
The first wireless station 501 receives the data with priority information by the spatial multiplexing antenna 507, passes through the antenna switching unit 543 switched in the reception direction, passes through the spatial multiplexing reception unit 529, and is transmitted by the channel decoding unit 540 with priority. Decrypted. At this time, if the signal of the spatial stream with high priority of the retransmitted signal can be correctly decoded and there is no communication hindrance, the channel decoding unit outputs a channel decoded signal. The decoding unit with priority 541 outputs a signal after decoding with priority, and the display unit 542 performs display.
This is an example of a case where the low priority data is the best effort, and the high priority data is a guarantee requiring retransmission control. When the QoS of the high priority data is also the best effort, the retransmission control is performed. Not performed. In that case, the retransmission control units 532 and 538 are unnecessary, and the delay time can be further reduced.
Even if all the data is the best effort, it is possible to easily transmit the high-priority data by assigning the high-priority data in the best effort to the high-priority spatial stream.
This corresponds to a case where the definition of best effort includes a best effort and a background with a lower QoS than that, and a case where a finer division called a level is performed within the same best effort.
With reference to FIG. 10A and FIG. 10B, the Example at the time of applying this invention to the system containing a several radio station is described.
In FIG. 10A, the first radio station 601, the second radio station 602, and the third radio station 603 perform spatial multiplexing communication. This method is known as multi-user MIMO and multi-base station cooperative MIMO. FIG. 10A shows an example in which the present invention is applied to such a system.
Propagation from the first radio station 601 to the second radio station 602 and the third radio station 603 is called the forward direction, and the opposite is called the reverse direction. Similar to the example described above, each wireless station transmits a known signal during transmission.
On the receiving side, the propagation path characteristics are calculated using a signal after determination that can be used as a known signal or a pseudo-known signal.
The second wireless station 602 and the third wireless station 603 notify the first wireless station 601 of the propagation path characteristics, and the first wireless station 601 generates a weight by combining the propagation path characteristics.
In the example of FIG. 10A, the propagation path characteristic between the j-th transmission antenna of the first radio station 601 and the k-th reception antenna of the u-th radio station is represented by h. _{(U−1) × K + k, j} And At this time, u = 2 and 3, and K is the number of receiving antennas of the second radio station 602 and the third radio station 603. At this time, since the propagation path matrix H can be obtained as follows, weight calculation and eigenvalue calculation can be performed in the same manner as in one-to-one communication.

FIG. 10B shows an example of cooperative communication, in which information with priority is transmitted from the fourth wireless station 604 and the fifth wireless station 605 to the sixth wireless station 606 and the seventh wireless station 607. In this method, the fourth radio station 604 and the fifth radio station 605, and the sixth radio station 606 and the seventh radio station 607 share the transmission signal and the reception signal, respectively.
The propagation path characteristic between the j-th transmitting antenna of the l-th wireless station and the k-th receiving antenna of the u-th wireless station is expressed as h. _{(U-4) × K + k, (1−6) × L + j} And At this time, l = 4,5, u = 6,7, L is the number of transmitting antennas of the fourth radio station and the fifth radio station, and K is the number of receiving antennas of the sixth radio station and the seventh radio station. . At this time, since the propagation path matrix H can be obtained as follows, weight calculation and eigenvalue calculation can be performed in the same manner as in one-to-one communication.

When there is data from the transmission side to a plurality of destinations, it is necessary to use the priority for each destination as the priority, and the priority information of the destination user is also taken into account. Examples of destination priority include a terminal class in 3GPP.
The present invention can also be applied to such multi-station communication. That is, even in a spatial stream between two or more stations, priority can be assigned like the spatial stream between two stations described so far, and communication can be performed according to the priority of data with priority.

The present invention can be applied to uses such as distribution of multimedia information in personal mobile communication. It can also be applied to uses such as cooperative communication of a plurality of radio stations.
This application is based on Japanese Patent Application No. 2007-325330 filed on Dec. 17, 2007 and Japanese Patent Application No. 2008-191303 filed on Jul. 24, 2008. Argue and incorporate all of its disclosure here.

Claims (26)

Sending data with priority composed of a plurality of data strings with priorities as a plurality of spatial streams via a spatial multiplexing channel,
A plurality of spatial streams received via the spatial multiplexing channel are demultiplexed and received,
By transmitting a known signal or a determined pseudo known signal to the spatial multiplex propagation path, the characteristics of the spatial multiplex propagation path are calculated and obtained as a propagation path calculated value,
Predicting the ease of deterioration of each spatial stream from the propagation path calculation value, assigning a priority of a low spatial stream to a high one that is difficult to deteriorate, and a low one easy to deteriorate,
According to the priority of the spatial stream, a communication method is characterized in that data having a higher priority is assigned to a spatial stream having a higher priority sequentially.   2. The calculation of the characteristics of the spatial multiplex propagation path according to claim 1, wherein the calculation of the characteristics of the spatial multiplex propagation path includes averaging the signal passing through the spatial multiplex propagation path by multiplying the complex conjugate of the known signal or the pseudo known signal. A communication method characterized by the above.   2. The transmission of the plurality of spatial streams according to claim 1, wherein a plurality of antenna elements are used or a plurality of spatial streams are formed using a plurality of polarizations of a single antenna element to perform spatial multiplexing transmission. A communication method characterized by comprising.   The demultiplexing reception of the plurality of spatial streams includes receiving using the polarization of a plurality of antenna elements or a single antenna element, and separating and receiving the plurality of spatial streams.   2. The communication method according to claim 1, wherein the priority assignment of the spatial stream includes setting a low priority to a spatial stream having a large eigenvalue calculated from the propagation path calculation value.   2. The priority assignment of the spatial stream according to claim 1, wherein when there are three or more spatial streams, a low priority is set for the spatial stream having the largest eigenvalue calculated from the propagation path calculation value and the eigenvalue is small. A communication method comprising: setting a low priority to a spatial stream.   2. The priority assignment of the spatial stream according to claim 1, wherein an unstable spatial stream and a stable spatial stream are detected from a previous propagation path calculation value, and a high priority is given to the stable spatial stream. A communication method comprising: setting a low priority for a simple spatial stream.   8. The repetitive communication according to claim 7, wherein the priority assignment of the spatial stream is calculated by calculating an eigenvector correlation between a previous eigenvector calculated from a previous propagation path calculation value and an eigenvector calculated from a current propagation path calculation value. When the eigenvector correlation amount is large, it is determined that the spatial stream is stable and a high priority is set, and when it is small, the spatial stream is determined to be unstable and a low priority is set. A communication method characterized by the above.   9. In the case of repeated communication according to claim 8, the priority assignment of the spatial stream is performed by comparing a propagation path change amount calculated from a previous propagation path calculation value and a current propagation path calculation value, and calculating the current propagation path. If the amount of change is large, it is determined to be unstable, and a low priority is set, and if the current channel change amount is small, it is determined to be stable and a high priority is set. A communication method characterized by the above.   2. The encoding method according to claim 1, further comprising: encoding the plurality of spatial streams including the priority-added data for each spatial stream, decoding the encoded spatial stream, wherein the priority is A communication method comprising: outputting a communication inhibition signal when decoding of maximum data fails, receiving the communication inhibition signal, and outputting a retransmission request signal.   The decoding of the encoded spatial stream according to claim 10, further comprising: not outputting a communication inhibition signal and not outputting the retransmission request signal when decoding of data whose priority is not maximum fails. A characteristic communication method. In response to input data, determine whether the input data is prioritized data composed of multiple data strings with priorities,
When it is determined that the input data is not data with priority, the channel information notification interval is set to a predetermined interval without performing assignment with priority, and
On the other hand, when it is determined that the input data is data with priority, allocation with priority is performed, and the propagation path information notification interval is set longer than the predetermined interval in the case of not being data with priority. And
Perform spatial multiplexing transmission / reception of multiple spatial streams through the spatial multiplexing propagation path,
In addition, the propagation path calculation value is calculated by using the known signal or using the determined signal as a pseudo known signal and multiplying the signal passing through the propagation path by the complex conjugate of the known signal and averaging. , While outputting the propagation path information based on the propagation path calculation value at the propagation path information notification interval,
Based on the propagation path calculation value, predict the ease of degradation of each spatial stream, assign the priority of the spatial stream high to the one that is difficult to degrade, and assign the priority of the low spatial stream to the one that is easy to degrade ,
In accordance with the communication capacity specified by the propagation path information, using the priority of data and the priority of the spatial stream obtained by setting the propagation path prediction priority, sequentially from the one with the higher priority of the data with priority, A communication method characterized by allocating to a spatial stream having a high priority.   A communication system using the communication method according to claim 1.   The communication apparatus used for the communication method as described in any one of Claim 1 to 12.   A communication method, comprising: assigning a spatial stream priority to a plurality of spatial streams based on propagation path prediction, and assigning data based on the spatial stream priority.   16. The communication method according to claim 15, wherein the data is data having a priority, and the data is allocated to the spatial stream based on both the priority of the spatial stream and the priority of the data.   A channel estimation unit that estimates the characteristics of a spatial multiplexing channel and outputs a channel calculation value, and a channel that predicts the priority of each spatial stream from the channel calculation value and sets the priority for each spatial stream A communication apparatus comprising: a prediction priority setting unit.   18. The channel prediction priority setting means according to claim 17, wherein the propagation path prediction priority setting means predicts the easiness of deterioration of a spatial stream, and assigns a low priority to the spatial stream that is high and difficult to deteriorate. A communication device comprising:   18. The propagation path estimation means according to claim 17, wherein the propagation path estimation means converts the known signal or the determined signal into a generation means for generating a pseudo known signal, and the known signal or the pseudo known signal that has passed through the spatial multiplexing propagation path. And a means for outputting a propagation path calculation value representing the characteristics of the spatially multiplexed propagation path by multiplying and averaging the complex conjugates of these signals.   18. The communication apparatus according to claim 17, further comprising data allocating means for allocating input data according to the priority of the spatial stream.   21. The priority allocation unit according to claim 20, wherein the data allocation unit receives data with priority as the input data, and allocates the spatial stream having a high priority to data having a high priority among the input data. A communication device comprising:   21. The data allocation unit according to claim 20, wherein the data allocation unit enables the priority allocation unit to determine the priority of the input data, and the priority allocation unit when the input data is data with priority. The communication apparatus further comprises means for lengthening the propagation path information notification interval as compared with the case where the input data is not data with priority.   A propagation path estimation circuit unit that estimates the characteristics of a spatial multiplexing channel and outputs a propagation path calculation value, and a propagation that predicts the priority of each spatial stream from the propagation path calculation value and sets the priority for each spatial stream A communication apparatus comprising: a road prediction priority setting circuit unit.   In a program used to control a communication apparatus that performs transmission and reception via a spatial multiplexing channel including a plurality of spatial streams, the characteristics of the spatial multiplexing channel for each spatial stream are estimated, and A program comprising: calculating an estimated value of a spatial multiplexing channel; and assigning a priority to each spatial stream based on the estimated value.   In Claim 24, the step of assigning the priority includes the step of predicting the ease of deterioration of each spatial stream, assigning a high priority to a spatial stream that is not easily degraded, and assigning a low priority to a spatial stream that is prone to degradation. And assigning the program.   In a recording medium storing a program used to control a communication device that transmits and receives via a spatial multiplexing channel including a plurality of spatial streams, the characteristics of the spatial multiplexing channel for each spatial stream are estimated, A computer-readable recording medium storing a program including a step of calculating an estimated value of the spatial multiplexing channel for each spatial stream and a step of assigning a priority to each spatial stream based on the estimated value.

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