JP2013081169A

JP2013081169A - Inter-cell interference elimination method, relay station, and base station

Info

Publication number: JP2013081169A
Application number: JP2012210426A
Authority: JP
Inventors: Xiaoli Wang; 王暁利; Yongsheng Zhang; 張永生
Original assignee: NTT Docomo Inc
Current assignee: NTT Docomo Inc
Priority date: 2011-09-30
Filing date: 2012-09-25
Publication date: 2013-05-02
Anticipated expiration: 2032-09-25
Also published as: CN103036643A; JP6039334B2; CN103036643B

Abstract

【課題】セル間干渉を効果的に除去して端ユーザのスループットを向上する。
【解決手段】セル間干渉除去方法は、中継局が、第１タイムスロットで、自局に隣接する基地局のカバー範囲内の移動端末から送信された信号を受信し、受信された信号に対して、ネットワーク符号化に基づく処理を行い、第２タイムスロットで、処理後の信号を、自局に隣接する基地局に転送する、ことを含む。該方法によれば、基地局は、中継局から転送された移動端末からの信号と、自局が直接に移動端末から受信した信号とを利用して、統合復号化を行って、自局の所要データを得ることができる。
【選択図】図１An object of the present invention is to effectively eliminate inter-cell interference and improve end user throughput.
In the inter-cell interference cancellation method, a relay station receives a signal transmitted from a mobile terminal within the coverage of a base station adjacent to the relay station in a first time slot, and receives the received signal. Then, processing based on network coding is performed, and the processed signal is transferred to the base station adjacent to the own station in the second time slot. According to this method, the base station performs joint decoding using the signal from the mobile terminal transferred from the relay station and the signal directly received from the mobile terminal by the local station, and Necessary data can be obtained.
[Selection] Figure 1

Description

本発明は、無線通信技術に関し、特に、セル間干渉除去方法、中継局および基地局に関する。 The present invention relates to a radio communication technique, and more particularly, to an inter-cell interference cancellation method, a relay station, and a base station.

現在のセルラーシステムにおいて、ユーザの獲得できるデータレートは、ユーザの所在する位置に大きく依存する。例えば、セルラーシステムにおけるセル端ユーザのデータレートは、セル中央ユーザより遥かに低い。これは、主に、信号の無線環境での伝搬特性から引き起こされる。当業者は、基地局から比較的に遠いユーザで受信された信号が、空間損失を経た後、その信号強度が必ず弱化するため、自然に、該ユーザの獲得できるデータレートが低減する、ということを理解できる。 In current cellular systems, the data rate that a user can obtain depends largely on the location of the user. For example, the data rate of cell edge users in cellular systems is much lower than cell center users. This is mainly caused by the propagation characteristics of the signal in the wireless environment. Those skilled in the art say that a signal received by a user who is relatively far from the base station is subjected to space loss, and its signal strength is always weakened, so that the data rate that can be acquired by the user is naturally reduced. Can understand.

基地局による端ユーザへの送信電力を増加することで空間損失を克服すれば、つまり、基地局は端ユーザへの送信電力を増加することで空間損失を克服すれば、該基地局による隣接セルへの干渉が増加してしまうことになり、これによって、相変わらず、隣接セルの端ユーザのデータレートが低減してしまうことになる。従って、セル間干渉を如何に解決するかという課題は、端ユーザのデータレートを向上させるために解決しようとする根本的な課題の１つである。 If the base station overcomes the spatial loss by increasing the transmission power to the end user, that is, if the base station overcomes the spatial loss by increasing the transmission power to the end user, the adjacent cell by the base station As a result, the data rate of the end user of the adjacent cell is reduced as usual. Therefore, the problem of how to solve inter-cell interference is one of the fundamental problems to be solved in order to improve the end user data rate.

上記の課題を解決するために、本発明の実施例は、セル間干渉を効果的に除去して端ユーザのスループットを向上させることが可能なセル間干渉除去方法と、該方法を実現する中継局および基地局とを提供している。 In order to solve the above-described problem, an embodiment of the present invention provides an inter-cell interference cancellation method capable of effectively eliminating inter-cell interference and improving end-user throughput, and a relay implementing the method. And base stations.

本発明の実施例で提供されているセル間干渉除去方法は、中継局が、第１タイムスロットで、自局に隣接する基地局のカバー範囲内の移動端末から送信された信号を受信し、中継局が、受信された信号に対して、ネットワーク符号化に基づく処理を行い、中継局が、第２タイムスロットで、処理後の信号を、自局に隣接する基地局に転送する、ことを含む。 In the inter-cell interference cancellation method provided in the embodiment of the present invention, a relay station receives a signal transmitted from a mobile terminal within the coverage of a base station adjacent to the relay station in a first time slot, The relay station performs processing based on network coding on the received signal, and the relay station transfers the processed signal to the base station adjacent to the own station in the second time slot. Including.

ここで、中継局が、受信された信号に対して、ネットワーク符号化に基づく処理を行うことは、中継局が、受信された信号に対して、増幅処理を行い、または、中継局が、受信された信号に対して、雑音除去および再変調処理を行い、または、中継局が、受信された信号に対して、雑音除去処理および圧縮処理を行う、ことを含み、またあるいは、中継局が、受信された信号に対して、ネットワーク符号化に基づく処理を行うことは、中継局と基地局との間のチャネル条件に基づいて、受信された信号に対して雑音除去処理を行う必要があるかどうかを判断し、受信された信号に対して雑音除去処理を行う必要がある場合、受信された信号に対して雑音除去処理を行ってから、ステップＢを実行し、受信された信号に対して雑音除去処理を行う必要がない場合、受信された信号を増幅するステップＡと、中継局と基地局との間のチャネル条件に基づいて、雑音除去処理後の信号を圧縮する必要があるかどうかを判断し、雑音除去処理後の信号を圧縮する必要がある場合、雑音除去処理後の信号を圧縮し、雑音除去処理後の信号を圧縮する必要がない場合、雑音除去処理後の信号を再変調するステップＢと、を含む。 Here, when the relay station performs a process based on network coding on the received signal, the relay station performs an amplification process on the received signal, or the relay station receives the signal. The received signal is subjected to noise removal and re-modulation processing, or the relay station performs noise removal processing and compression processing on the received signal. Is it necessary to perform noise reduction processing on the received signal based on the channel conditions between the relay station and the base station to perform processing based on network coding on the received signal? If it is necessary to perform noise removal processing on the received signal, step B is performed after performing noise removal processing on the received signal. Perform noise reduction processing If it is not necessary, it is determined whether or not the signal after the noise removal processing needs to be compressed based on the step A for amplifying the received signal and the channel condition between the relay station and the base station. Step B for re-modulating the signal after the noise removal processing when the signal after the noise removal processing needs to be compressed, and the signal after the noise removal processing need not be compressed. ,including.

上記の方法は、基地局が、第１タイムスロットで、自局および自局に隣接する基地局のカバー範囲内の移動端末から送信された信号を受信し、基地局が、第２タイムスロットで、中継局から送信された処理後の信号を受信し、基地局が、自局が第１タイムスロットで受信した信号と第２タイムスロットで受信した信号とに基づいて、統合復号化を行って、自局のカバー範囲内の移動端末から送信された信号を得る、ことをさらに含む。 In the above method, the base station receives the signal transmitted from the mobile station within the coverage of the base station and the base station adjacent to the base station in the first time slot, and the base station receives the signal in the second time slot. The base station receives the processed signal transmitted from the relay station, and performs base decoding based on the signal received by the base station in the first time slot and the signal received in the second time slot. And obtaining a signal transmitted from a mobile terminal within the coverage of the local station.

基地局が、自局が第１タイムスロットで受信した信号と第２タイムスロットで受信した信号とに基づいて、統合復号化を行うことは、基地局が、まず、自局が第１タイムスロットで受信した、自局および自局に隣接する基地局のカバー範囲内の移動端末から送信された信号と、第２タイムスロットで受信した、中継局から送信された処理後の信号とに対して、統合検出を行って、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比を得、次に、復号器で復号化して、自局のカバー範囲内の移動端末から送信された信号を得る、ことを含む。ここで、上記の復号器は、例えばＴｕｒｂｏ復号器やＬＤＰＣ復号器などのような、ソフト情報復号化をサポートできる復号器である。 Based on the signal received by the base station in the first time slot and the signal received in the second time slot, the base station first performs base decoding by the base station in the first time slot. And the signal transmitted from the mobile station within the coverage of the base station and the base station adjacent to the local station, and the processed signal transmitted from the relay station received in the second time slot. The integrated detection is performed to obtain the log-likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage range of the local station, and then the decoding is performed by the decoder so as to be within the coverage range of the local station. Obtaining a signal transmitted from the mobile terminal. Here, the decoder is a decoder that can support soft information decoding, such as a Turbo decoder or an LDPC decoder.

中継局が、受信された信号に対して、ネットワーク符号化に基づく処理を行うことは、前記中継局が、受信された信号に対して、増幅処理を行う、ことを含み、前記統合検出は、前記基地局が、数式
によって、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比を得る、ことを含む。 The relay station performing a process based on network coding on the received signal includes the relay station performing an amplification process on the received signal, and the integrated detection includes: The base station has the formula
To obtain the log likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage of the local station.

ここで、Ｐ（ｙ_１（１），ｙ_１（２）／ｘ_１，ｘ_２）＝Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）・Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）であり、Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）、Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）は、数式
、
によって算出し、ｙ_１（１）は、第１基地局ＢＳ１が第１タイムスロットで受信した第１混合信号を代表し、ｙ_１（２）は、第１基地局ＢＳ１が第２タイムスロットで受信した第３混合信号を代表し、ｈ_１１は、第１移動端末ＭＳ１から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｈ_２１は、第２移動端末ＭＳ２から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｘ_１とｘ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２が第１タイムスロットで送信した信号をそれぞれ代表し、ｇ_１とｇ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２から中継局へのチャネルの信号インパルス応答をそれぞれ代表し、ｇ_３とｇ_４は、中継局から第１基地局ＢＳ１と第２基地局ＢＳ２へのチャネルの信号インパルス応答をそれぞれ代表し、Ｎ_０は、雑音の電力スペクトル密度を代表し、αは、中継局の電力増幅因子であり、Ｓ_０は、特定位置のビットが０である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓ_１は、特定位置のビットが１である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓは、ＱＡＭ変調に含まれる全てのコンスタレーションポイントを表す。 Here, P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) = P (y ₁ (1) / x ₁ , x ₂ ) · P (y ₁ (2) / x ₁ , x ₂ ), and P (y ₁ (1) / x ₁ , x ₂ ), P (y ₁ (2) / x ₁ , x ₂ )
,
Y ₁ (1) represents the first mixed signal received by the first base station BS1 in the first time slot, and y ₁ (2) represents the first base station BS1 in the second time slot. Representing the received third mixed signal, h ₁₁ represents the signal impulse response of the channel from the first mobile terminal MS1 to the first base station BS1, and h ₂₁ represents the first base station from the second mobile terminal MS2. on behalf of the channel signal impulse response to BS1, _{x 1} and _{x 2} is provided with a first mobile terminal MS1 the second mobile terminal MS2 a signal transmitted by the first time slot representative respectively, _{g 1} and _{g 2} are a first mobile terminal MS1 behalf each channel signal impulse response to the relay station from the second mobile terminal MS2, _{g 3} and _{g 4} is from the relay station to the first base station BS1 second base station BS2 Channel signal imper Scan response representative respectively, N ₀ is representative of the power spectral density of the noise, alpha is the power amplification factor of the repeater station, S ₀ is QAM modulated corresponding to when the bit of a specific position is 0 This refers to a constellation point, S ₁ refers to a QAM modulation constellation point corresponding to the case where the bit at a specific position is 1, and S represents all constellation points included in the QAM modulation.

中継局が、受信された信号に対して、ネットワーク符号化に基づく処理を行うことは、前記中継局が、受信された信号に対して、雑音除去および再変調処理を行う、ことを含み、ここで、前記雑音除去は、数式
によって実現し、前記再変調処理は、中継局が、
を得た後、
に基づいて、受信された第２混合信号における第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信されたシンボルのコンステレーション内の位置
を決定し、それから、Ｓ^（１）とＳ^（２）よりも高次の変調コンステレーションを利用して、受信された第２混合信号を再変調し、ｘ_ｒを生成して転送する、ことを含み、前記統合検出は、前記基地局が、数式
によって、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比を得る、ことを含み、ここで、Ｐ（ｙ_１（１），ｙ_１（２）／ｘ_１，ｘ_２）＝Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）・Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）であり、Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）、Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）は、数式
、
によって算出し、ｙ_１（１）は、第１基地局ＢＳ１が第１タイムスロットで受信した第１混合信号を代表し、ｙ_１（２）は、第１基地局ＢＳ１が第２タイムスロットで受信した第３混合信号を代表し、ｙ_ｒは、中継局が第１タイムスロットで受信した第２混合信号を代表し、ｈ_１１は、第１移動端末ＭＳ１から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｈ_２１は、第２移動端末ＭＳ２から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｘ_１とｘ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２が第１タイムスロットで送信した信号をそれぞれ代表し、ｘ_ｒは、処理後の第２混合信号を代表し、ｇ_１とｇ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２から中継局へのチャネルの信号インパルス応答をそれぞれ代表し、ｇ_３は、中継局から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、Ｎ_０は、雑音の電力スペクトル密度を代表し、Ｓ_０は、特定位置のビットが０である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓ_１は、特定位置のビットが１である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓは、ＱＡＭ変調に含まれる全てのコンスタレーションポイントを表し、Ｓ^（１）とＳ^（２）は、第１移動端末ＭＳ１と第２移動端末ＭＳ２で採用されている変調コンスタレーションをそれぞれ表し、Ｓ_ｍｉｎ ^（１）とＳ_ｍｉｎ ^（２）は、中継局で推定された、第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信されたシンボルをそれぞれ代表する。 The relay station performing processing based on network coding on the received signal includes that the relay station performs noise removal and re-modulation processing on the received signal, And the noise removal
The re-modulation processing is realized by the relay station,
After getting
Based on the position in the constellation of the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 in the received second mixed signal
Remodulate the received second mixed signal using a higher order modulation constellation than S ⁽¹⁾ and S ⁽²⁾ to generate and transmit x _r , The integrated detection is performed by the base station using the formula
To obtain the log-likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage of the local station, where P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) = P (y ₁ (1) / x ₁ , x ₂ ) · P (y ₁ (2) / x ₁ , x ₂ ), and P (y ₁ (1) / x ₁ , x ₂ ), P (y ₁ (2) / x ₁ , x ₂ )
,
Y ₁ (1) represents the first mixed signal received by the first base station BS1 in the first time slot, and y ₁ (2) represents the first base station BS1 in the second time slot. On behalf of the third mixed signal received, y _r is representative of the second mixed signal relay station receives the first time slot, h _11, the channel from the first mobile terminal MS1 to the first base station BS1 on behalf of the signal impulse _{response, h 21,} from the second mobile terminal MS2 behalf of the channel signal impulse response of the first base station BS1, _{x 1} and _{x 2} is provided with a first mobile terminal MS1 second movement On behalf respectively a signal terminal MS2 is transmitted in the first time slot, _{x r} is representative of the second mixed signal after processing, _{g 1} and _{g 2} includes a first mobile terminal MS1 from the second mobile terminal MS2 Signal impulse of channel to relay station Answer was representative respectively, g ₃ is representative of the channel signal impulse response from the relay station to the first base station BS1, N ₀ is representative of the power spectral density of the noise, S _0, the bit of a specific location Indicates the corresponding QAM modulation constellation point when S is 0, S ₁ indicates the corresponding QAM modulation constellation point when the bit at a specific position is 1, and S indicates all the QAM modulation constellation points S ⁽¹⁾ and S ⁽²⁾ represent modulation constellations adopted by the first mobile terminal MS1 and the second mobile terminal MS2, respectively, and S _min ⁽¹⁾ and S _min ^{(2 )} Represents the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 estimated by the relay station, respectively.

中継局が、受信された信号に対して、ネットワーク符号化に基づく処理を行うことは、前記中継局が、受信された信号に対して、雑音除去および圧縮処理を行う、ことを含み、ここで、前記雑音除去は、数式
によって実現し、前記圧縮処理は、中継局が、
を得た後、
に基づいて、受信された第２混合信号における第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信されたシンボルのコンステレーション内の位置
を決定し、それから、数式
によって、コンステレーションマッピングを行い、ｘ_ｒを生成して転送する、ことを含み、前記統合検出は、前記基地局が、数式
によって、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比を得る、ことを含み、ここで、Ｐ（ｙ_１（１），ｙ_１（２）／ｘ_１，ｘ_２）＝Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）・Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）であり、Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）、Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）は、数式
、
によって算出し、ｙ_１（１）は、第１基地局ＢＳ１が第１タイムスロットで受信した第１混合信号を代表し、ｙ_１（２）は、第１基地局ＢＳ１が第２タイムスロットで受信した第３混合信号を代表し、ｙ_ｒは、中継局が第１タイムスロットで受信した第２混合信号を代表し、ｈ_１１は、第１移動端末ＭＳ１から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｈ_２１は、第２移動端末ＭＳ２から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｘ_１とｘ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２が第１タイムスロットで送信した信号をそれぞれ代表し、ｘ_ｒは、処理後の第２混合信号を代表し、ｇ_１とｇ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２から中継局へのチャネルの信号インパルス応答をそれぞれ代表し、ｇ_３は、中継局から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、Ｎ_０は、雑音の電力スペクトル密度を代表し、Ｓ_０は、特定位置のビットが０である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓ_１は、特定位置のビットが１である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓは、ＱＡＭ変調に含まれる全てのコンスタレーションポイントを表し、Ｓ^（１）とＳ^（２）は、第１移動端末ＭＳ１と第２移動端末ＭＳ２で採用されている変調コンスタレーションをそれぞれ表し、Ｓ_ｍｉｎ ^（１）とＳ_ｍｉｎ ^（２）は、中継局で推定された、第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信されたシンボルをそれぞれ代表する。 The relay station performing processing based on network coding on the received signal includes that the relay station performs noise removal and compression processing on the received signal, where , The noise removal is a mathematical formula
The compression processing is realized by the relay station,
After getting
Based on the position in the constellation of the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 in the received second mixed signal
And then the formula
The performs constellation mapping, and transfers to generate x _r, said method comprising, the integration detection, the base station, the formula
To obtain the log-likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage of the local station, where P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) = P (y ₁ (1) / x ₁ , x ₂ ) · P (y ₁ (2) / x ₁ , x ₂ ), and P (y ₁ (1) / x ₁ , x ₂ ), P (y ₁ (2) / x ₁ , x ₂ )
,
Y ₁ (1) represents the first mixed signal received by the first base station BS1 in the first time slot, and y ₁ (2) represents the first base station BS1 in the second time slot. On behalf of the third mixed signal received, y _r is representative of the second mixed signal relay station receives the first time slot, h _11, the channel from the first mobile terminal MS1 to the first base station BS1 on behalf of the signal impulse _{response, h 21,} from the second mobile terminal MS2 behalf of the channel signal impulse response of the first base station BS1, _{x 1} and _{x 2} is provided with a first mobile terminal MS1 second movement On behalf respectively a signal terminal MS2 is transmitted in the first time slot, _{x r} is representative of the second mixed signal after processing, _{g 1} and _{g 2} includes a first mobile terminal MS1 from the second mobile terminal MS2 Signal impulse of channel to relay station Answer was representative respectively, g ₃ is representative of the channel signal impulse response from the relay station to the first base station BS1, N ₀ is representative of the power spectral density of the noise, S _0, the bit of a specific location Indicates the corresponding QAM modulation constellation point when S is 0, S ₁ indicates the corresponding QAM modulation constellation point when the bit at a specific position is 1, and S indicates all the QAM modulation constellation points S ⁽¹⁾ and S ⁽²⁾ represent modulation constellations adopted by the first mobile terminal MS1 and the second mobile terminal MS2, respectively, and S _min ⁽¹⁾ and S _min ^{(2 )} Represents the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 estimated by the relay station, respectively.

上記の方法は、統合データ転送を行う移動端末ペアを決定する、ことをさらに含んでよい。 The above method may further comprise determining a mobile terminal pair to perform integrated data transfer.

ここで、統合データ転送を行う移動端末ペアを決定することは、移動端末が、本セルと隣接セルの基準信号を測定し、本セルと隣接セルの基準信号の強度の差が所定の基準信号閾値より小さい場合、該移動端末が、本セルの基地局へ、隣接セルのＩＤと本セルの直送リンクのチャネル条件とを報告し、基地局が、移動端末に対し、転送リンクを介して転送された本セルの基準信号を測定するよう通知し、移動端末が、測定して得られた、転送リンクを介して転送された本セルの基準信号から、転送リンクのチャネル条件を得、転送リンクのチャネル条件を本セルの基地局へ報告し、本セルの直送リンクのチャネル条件と転送リンクのチャネル条件とに基づいて、転送リンクの品質が直送リンクより優れているかどうかを判断し、転送リンクの品質が直送リンクより優れている場合、該移動端末を候補リストに追加し、自局の候補リスト中の１つの移動端末と、隣接セルの候補リスト中の１つの移動端末とをランダムに選択して、統合データ転送を行う移動端末ペアとする、ことを含む。 Here, determining the mobile terminal pair that performs the integrated data transfer means that the mobile terminal measures the reference signal between the main cell and the adjacent cell, and the difference in intensity between the reference signal between the main cell and the adjacent cell is a predetermined reference signal If it is smaller than the threshold value, the mobile terminal reports the ID of the neighboring cell and the channel condition of the direct transmission link of the cell to the base station of the present cell, and the base station transfers to the mobile terminal via the transfer link The mobile terminal obtains the channel condition of the transfer link from the reference signal of the main cell transferred via the transfer link obtained by the measurement, and transmits the channel condition of the transfer link. The channel condition of the cell is reported to the base station of the cell, and based on the channel condition of the direct transmission link of the cell and the channel condition of the transfer link, it is determined whether the quality of the transfer link is superior to that of the direct link. of If the quality is better than the direct link, add the mobile terminal to the candidate list, and randomly select one mobile terminal in the candidate list of the local station and one mobile terminal in the candidate list of the neighboring cell Mobile terminal pairs that perform integrated data transfer.

あるいは、統合データ転送を行う移動端末ペアを決定することは、中継局が、隣接セルの移動端末から送信された基準信号を監視し、２つのセルの移動端末からの基準信号の強度の差が所定の第１閾値より小さくて、かつ、前記２つのセルの移動端末からの基準信号の強度がいずれも所定の第２閾値より大きい場合、中継局が、前記２つのセルの移動端末からの基準信号のフォーマットを、前記２つのセルの基地局へ通知し、前記２つのセルの基地局が、受信された基準信号のフォーマットに基づいて、前記２つのセルの移動端末のＩＤをそれぞれ決定して、該ＩＤに対応する移動端末を自局の候補リストに追加し、自局の候補リスト中の１つの移動端末と隣接セルの候補リスト中の１つの移動端末とをランダムに選択して、統合データ転送を行う移動端末ペアとする、ことを含む。 Alternatively, determining a pair of mobile terminals that perform integrated data transfer means that a relay station monitors a reference signal transmitted from a mobile terminal in an adjacent cell, and a difference in strength of the reference signals from mobile terminals in two cells is detected. If the reference signal from the mobile terminals of the two cells is smaller than the predetermined first threshold and the strength of the reference signals from the mobile terminals of the two cells are both higher than the predetermined second threshold, Signal formats are notified to the base stations of the two cells, and the base stations of the two cells determine IDs of the mobile terminals of the two cells based on the received reference signal formats, respectively. The mobile terminal corresponding to the ID is added to the candidate list of the own station, and one mobile terminal in the candidate list of the own station and one mobile terminal in the candidate list of the neighboring cell are randomly selected and integrated. data transfer A mobile terminal pair for performing comprises.

また、前記中継局は、現時点で空いている基地局によって実現してよい。 The relay station may be realized by a base station that is currently available.

本発明の実施例で提供される中継局は、第１タイムスロットで、移動端末からの混合信号を受信する混合信号受信手段と、受信された混合信号に対して、ネットワーク符号化に基づく処理を行う混合信号処理手段と、第２タイムスロットで、処理後の混合信号を、自局に隣接する基地局に転送する混合信号転送手段と、を含む。 A relay station provided in an embodiment of the present invention includes a mixed signal receiving unit that receives a mixed signal from a mobile terminal in a first time slot, and performs processing based on network coding on the received mixed signal. Mixed signal processing means for performing, and mixed signal transfer means for transferring the processed mixed signal to a base station adjacent to the own station in the second time slot.

本発明の実施例で提供される基地局は、第１タイムスロットで直接に移動端末から受信された混合信号と、第２タイムスロットで中継局から受信された混合信号とに対して、統合検出を行って、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比を得る統合検出手段と、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比に基づいて、復号化を行って、自局のカバー範囲内の移動端末から送信された信号を得る復号器と、を含む。上記の復号器は、例えばＴｕｒｂｏ復号器やＬＤＰＣ復号器などのような、ソフト情報復号化をサポートできる復号器である。 The base station provided in the embodiment of the present invention performs integrated detection on the mixed signal received directly from the mobile terminal in the first time slot and the mixed signal received from the relay station in the second time slot. Integrated detection means for obtaining a log-likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage range of the local station, and the signal transmitted from the mobile terminal within the coverage range of the local station A decoder that performs decoding based on the log likelihood ratio of each bit included to obtain a signal transmitted from a mobile terminal within the coverage of the local station. The above decoder is a decoder that can support soft information decoding, such as a Turbo decoder or an LDPC decoder.

上記のように、本発明の実施例では、隣接する基地局の間に中継局ＲＳを導入し、かつ、中継局が、自局で受信された移動端末からの信号を処理してから、自局に隣接する基地局に転送するようにすることにより、基地局は、中継局から転送された移動端末からの信号と、自局が直接に移動端末から受信した信号とを利用して、統合復号化を行って、自局の所要データを得ることができる。これにより、セル間干渉の問題を効果的に解決し、セル端ユーザのスループットを向上させる。 As described above, in the embodiment of the present invention, the relay station RS is introduced between adjacent base stations, and the relay station processes the signal from the mobile terminal received by itself, and then By transferring to the base station adjacent to the station, the base station integrates using the signal from the mobile terminal transferred from the relay station and the signal received by the local station directly from the mobile terminal. Decoding can be performed to obtain the required data of the local station. This effectively solves the problem of inter-cell interference and improves the throughput of cell edge users.

本発明に係るセル間干渉除去方法のフローチャートである。3 is a flowchart of an inter-cell interference cancellation method according to the present invention. 本発明に係るセル間干渉除去方法が応用される無線通信システムの構成を示す図である。It is a figure which shows the structure of the radio | wireless communications system with which the inter-cell interference removal method which concerns on this invention is applied. 本発明の実施例に係る中継局が処理方式を適応的に選択するフローチャートである。6 is a flowchart in which a relay station according to an embodiment of the present invention adaptively selects a processing method. 本発明の実施例に係る中継局の内部構成を示す図である。It is a figure which shows the internal structure of the relay station based on the Example of this invention. 本発明の実施例に係る基地局の内部構成を示す図である。It is a figure which shows the internal structure of the base station which concerns on the Example of this invention. 中継局と移動端末との間の距離が１０メートルと５０メートルであるとき、中継局を有しない場合（ａ）および本発明の実施例１〜３に係る方法を採用する場合（ｂ）の信号対雑音比（ＳＮＲ）とブロック誤り率（ＢＬＥＲ）との関係をそれぞれ示すグラフである。Signals when the distance between the relay station and the mobile terminal is 10 meters and 50 meters, when there is no relay station (a), and when the methods according to the first to third embodiments of the present invention are employed (b) It is a graph which shows the relationship between a noise ratio (SNR) and a block error rate (BLER), respectively. 本発明の実施例における統合データ転送を行う移動端末ペアを如何に選択するかという方法のフローチャートである。4 is a flowchart of a method of selecting a mobile terminal pair for performing integrated data transfer according to an embodiment of the present invention. 本発明のほかの実施例における統合データ転送を行う移動端末ペアを如何に選択するかという方法のフローチャートである。6 is a flowchart of a method of selecting a mobile terminal pair for performing integrated data transfer according to another embodiment of the present invention. ネットワークトポロジーを示す図である。It is a figure which shows a network topology.

本発明の目的、解決手段およびメリットをさらに明確にするために、以下、図面および実施例を参照しながら、本発明をさらに詳しく説明する。理解すべきものとして、ここで述べた具体的な実施例は、本発明を解釈するものにすぎず、本発明を限定するものではない。 In order to further clarify the objects, solutions and merits of the present invention, the present invention will be described in more detail below with reference to the drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

本発明では、セル間干渉除去方法が提供されている。該方法では、隣接する基地局の間に中継局（ＲＳ：ｒｅｌａｙｓｔａｔｉｏｎ）が設けられ、図１に示すように、該方法は、下記のステップを含む。 In the present invention, an inter-cell interference cancellation method is provided. In the method, a relay station (RS) is provided between adjacent base stations, and as shown in FIG. 1, the method includes the following steps.

ステップ１０１で、中継局は、第１タイムスロットで、自局に隣接する基地局のカバー範囲内の移動端末から送信された信号を受信する。 In step 101, the relay station receives a signal transmitted from a mobile terminal within the coverage of a base station adjacent to the relay station in the first time slot.

ステップ１０２で、中継局は、受信された信号に対して、ネットワーク符号化に基づく処理を行う。 In step 102, the relay station performs processing based on network coding on the received signal.

ステップ１０３で、中継局は、第２タイムスロットで、処理後の信号を、自局に隣接する基地局に転送する。 In step 103, the relay station transfers the processed signal to the base station adjacent to the local station in the second time slot.

本発明で提供されている上記のセル間干渉除去方法において、基地局は、第１タイムスロットで、自局および自局に隣接する基地局のカバー範囲内の移動端末から送信された信号を受信し、第２タイムスロットで、中継局から送信された処理後の信号を受信し、自局が第１タイムスロットで受信した信号と第２タイムスロットで受信した信号とに基づいて、統合復号化を行って、自局のカバー範囲内の移動端末から送信された信号を得る。 In the inter-cell interference cancellation method provided in the present invention, the base station receives a signal transmitted from the mobile station within the coverage of the base station and the base station adjacent to the base station in the first time slot. And receiving the processed signal transmitted from the relay station in the second time slot and performing joint decoding based on the signal received by the local station in the first time slot and the signal received in the second time slot. To obtain a signal transmitted from a mobile terminal within the coverage of the local station.

以下、図２を参照しながら、上記方法を詳しく説明する。図２は、本発明に係る方法が応用される無線通信システムの構成を示す図である。 Hereinafter, the above method will be described in detail with reference to FIG. FIG. 2 is a diagram showing a configuration of a wireless communication system to which the method according to the present invention is applied.

図２に示すように、隣接する第１基地局ＢＳ１と第２基地局ＢＳ２との間の干渉を解決するために、隣接する第１基地局ＢＳ１と第２基地局ＢＳ２との間に、中継局ＲＳが導入される。この中継局があれば、第１基地局ＢＳ１のカバー範囲内の第１移動端末ＭＳ１と第２基地局ＢＳ２のカバー範囲内の第２移動端末ＭＳ２とは、同時にデータを送信することができ、送信データは、第１タイムスロットで、第１基地局ＢＳ１、第２基地局ＢＳ２および中継局ＲＳに送信される。このとき、第１基地局ＢＳ１と第２基地局ＢＳ２で受信されたのは、第１混合信号と呼ばれる混合信号である。第１混合信号は、下記の数式１と２によって算出できる。
As shown in FIG. 2, in order to resolve interference between adjacent first base station BS1 and second base station BS2, relay is performed between adjacent first base station BS1 and second base station BS2. Station RS is introduced. With this relay station, the first mobile terminal MS1 within the coverage of the first base station BS1 and the second mobile terminal MS2 within the coverage of the second base station BS2 can transmit data simultaneously, The transmission data is transmitted to the first base station BS1, the second base station BS2, and the relay station RS in the first time slot. At this time, what is received by the first base station BS1 and the second base station BS2 is a mixed signal called a first mixed signal. The first mixed signal can be calculated by the following formulas 1 and 2.

ここで、ｙ_１（１）とｙ_２（１）は、第１基地局ＢＳ１と第２基地局ＢＳ２が第１タイムスロットで受信した第１混合信号をそれぞれ代表し、ｈ_１１は、第１移動端末ＭＳ１から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｈ_１２は、第１移動端末ＭＳ１から第２基地局ＢＳ２へのチャネルの信号インパルス応答を代表し、ｈ_２１は、第２移動端末ＭＳ２から第１基地局ＢＳ１へのチャネルの信号インパルス応答を代表し、ｈ_２２は、第２移動端末ＭＳ２から第２基地局ＢＳ２へのチャネルの信号インパルス応答を代表し、ｘ_１とｘ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２が第１タイムスロットで送信した信号をそれぞれ代表し、ｚ_１とｚ_２は、第１基地局ＢＳ１と第２基地局ＢＳ２の受信機の雑音をそれぞれ代表する。 Here, y ₁ (1) and y ₂ (1) represent the first mixed signal received by the first base station BS1 and the second base station BS2 in the first time slot, respectively, and h ₁₁ represents the first The signal impulse response of the channel from the mobile terminal MS1 to the first base station BS1 is representative, h ₁₂ is representative of the signal impulse response of the channel from the first mobile terminal MS1 to the second base station BS2, and h ₂₁ is The signal impulse response of the channel from the second mobile terminal MS2 to the first base station BS1 is representative, h ₂₂ is representative of the signal impulse response of the channel from the second mobile terminal MS2 to the second base station BS2, and x ₁ and _{x 2} is provided with a first mobile terminal MS1 second mobile terminal MS2 a signal transmitted in the first time slot representative respectively, _{z 1} and _{z 2} includes a first base station BS1 receives the second base station BS2 The noise of the machine Each representative.

上記の数式から分かるように、セル間干渉が存在しているため、第１基地局ＢＳ１と第２基地局ＢＳ２は、第１タイムスロットで受信したのが混合信号であり、復調することにより自局の所要データを正確に得る（第１基地局ＢＳ１は第１移動端末ＭＳ１から送信されたデータを得、第２基地局ＢＳ２は第２移動端末ＭＳ２から送信されたデータを得る）ことができない。 As can be seen from the above equation, since there is inter-cell interference, the first base station BS1 and the second base station BS2 receive the mixed signal in the first time slot and demodulate themselves by demodulating. The required data of the station cannot be obtained accurately (the first base station BS1 obtains the data transmitted from the first mobile terminal MS1 and the second base station BS2 obtains the data transmitted from the second mobile terminal MS2) .

信号の空間ブロードキャスト特性によって、中継局ＲＳも第１タイムスロットで、第２混合信号と呼ばれる混合信号を受信することになる。第２混合信号は、下記の数式３によって算出できる。
Due to the spatial broadcast characteristics of the signal, the relay station RS also receives the mixed signal called the second mixed signal in the first time slot. The second mixed signal can be calculated by Equation 3 below.

ここで、ｙ_ｒは、中継局が第１タイムスロットで受信した第２混合信号を代表し、ｇ_１とｇ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２から中継局へのチャネルの信号インパルス応答をそれぞれ代表し、ｘ_１とｘ_２は、第１移動端末ＭＳ１と第２移動端末ＭＳ２が第１タイムスロットで送信した信号をそれぞれ代表し、ｚ_ｒは、中継局の受信機の雑音を代表する。 Here, y _r represents the second mixed signal received by the relay station in the first time slot, and g ₁ and g ₂ represent the channel from the first mobile terminal MS1 and the second mobile terminal MS2 to the relay station. a signal impulse response representative respectively, x ₁ and x ₂ is provided with a first mobile terminal MS1 second mobile terminal MS2 behalf each transmitted signal at a first time slot, z _r is the receiver of the relay station Represents noise.

中継局ＲＳは、受信された第２混合信号を処理した後、第２タイムスロットで、処理後の第２混合信号を、第１基地局ＢＳ１と第２基地局ＢＳ２にブロードキャストする。このようにして、第１基地局ＢＳ１と第２基地局ＢＳ２は、第２タイムスロットで、第３混合信号と呼ばれるほかの混合信号を受信することになる。第３混合信号は、下記の数式４と５によって算出できる。
After processing the received second mixed signal, the relay station RS broadcasts the processed second mixed signal to the first base station BS1 and the second base station BS2 in the second time slot. In this way, the first base station BS1 and the second base station BS2 receive another mixed signal called the third mixed signal in the second time slot. The third mixed signal can be calculated by the following equations 4 and 5.

ここで、ｙ_１（２）とｙ_２（２）は、第１基地局ＢＳ１と第２基地局ＢＳ２が第２タイムスロットで受信した第３混合信号をそれぞれ代表し、ｇ_３とｇ_４は、中継局から第１基地局ＢＳ１と第２基地局ＢＳ２へのチャネルの信号インパルス応答をそれぞれ代表し、ｘ_ｒは、処理後の第２混合信号を代表する。 Here, y ₁ (2) and y ₂ (2) represent the third mixed signal received by the first base station BS1 and the second base station BS2 in the second time slot, respectively, and g ₃ and g ₄ , represent respectively a channel signal impulse response from the relay station to the first base station BS1 second base station BS2, x _r is representative of a second mixed signal after processing.

最後に、第１基地局ＢＳ１と第２基地局ＢＳ２は、自局が第１タイムスロットで受信した第１混合信号と、第２タイムスロットで受信した中継局からの第３混合信号とに基づいて、それぞれ統合復号化を行って、自局の所要データを得る。つまり、第１基地局ＢＳ１は、上記のｙ_１（１）とｙ_１（２）とに基づいて、統合復号化を行って、ｘ_１を得、第２基地局ＢＳ２は、上記のｙ_２（１）とｙ_２（２）とに基づいて、統合復号化を行って、ｘ_２を得る。 Finally, the first base station BS1 and the second base station BS2 are based on the first mixed signal received by the local station in the first time slot and the third mixed signal from the relay station received in the second time slot. Then, integrated decoding is performed to obtain necessary data of the local station. That is, the first base station BS1 on the basis of the above _y 1 (1) and _y 1 (2), performs integration decoding, to obtain the _{x 1,} the second base station BS2, the above _{y 2} Based on (1) and y ₂ (2), joint decoding is performed to obtain x ₂ .

具体的に、上記の統合復号化は、基地局が、まず、自局が第１タイムスロットで受信した移動端末からの第１混合信号と、第２タイムスロットで受信した中継局からの第３混合信号とに対して、統合検出を行って、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比（ＬＬＲ）を得、それから、復号器で復号化して、自局のカバー範囲内の移動端末から送信された信号を得る。ここでの復号器は、例えばＴｕｒｂｏ復号器やＬＤＰＣ復号器などのような、ソフト情報復号化をサポートする復号器である。 Specifically, in the above-described joint decoding, the base station first receives the first mixed signal from the mobile terminal received by the local station in the first time slot and the third mixed signal from the relay station received in the second time slot. An integrated detection is performed on the mixed signal to obtain a log likelihood ratio (LLR) of each bit included in the signal transmitted from the mobile terminal within the coverage of the local station, and then decoded by the decoder Thus, a signal transmitted from the mobile terminal within the coverage area of the local station is obtained. The decoder here is a decoder that supports soft information decoding, such as a Turbo decoder or an LDPC decoder, for example.

以下、第１基地局ＢＳ１、並びに、第１移動端末ＭＳ１および第２移動端末ＭＳ２がいずれもＱＡＭ変調方式を採用することを例として、基地局が第１混合信号と第３混合信号とに基づいて、統合検出を行って、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比（ＬＬＲ）を得る方法について、詳しく説明する。 Hereinafter, based on the first base station BS1 and the first mobile terminal MS1 and the second mobile terminal MS2 both adopt the QAM modulation scheme as an example, the base station is based on the first mixed signal and the third mixed signal. A method of performing integrated detection and obtaining a log likelihood ratio (LLR) of each bit included in a signal transmitted from a mobile terminal within the coverage of the local station will be described in detail.

上記のように、第１基地局ＢＳ１で取得された信号は、ｙ_１（１）＝ｈ_１１ｘ_１＋ｈ_２１ｘ_２＋ｚ_１とｙ_１（２）＝ｇ_３ｘ_ｒ＋ｚ_１とを含む。第１移動端末ＭＳ１で採用されているのはＱＡＭ変調方式であれば、第１基地局ＢＳ１は、まず、統合検出を行うことで、信号Ｘ_１で代表するＱＡＭシンボルに含まれる２つのビットｂ１とｂ２のＬＬＲ情報を得る必要がある。 As described above, the signal acquired by the first base station BS1 includes y ₁ (1) = h ₁₁ x ₁ + h ₂₁ x ₂ + z ₁ and y ₁ (2) = g ₃ x _r + z ₁ . If QAM modulation scheme what is employed in the first mobile terminal MS1, the first base station BS1, first, by performing integration detection, two bits included in QAM symbol represented by a signal X ₁ b1 And b2 LLR information needs to be obtained.

本例では、第１基地局ＢＳ１は、下記の数式６によって、信号Ｘ_１に含まれる２つのビットｂ１とｂ２のＬＬＲ情報を決定することができる。
In this example, the first base station BS1, according to Equation 6 below, it is possible to determine two LLR information of the bit b1 and b2 in the signal _{X 1.}

ここで、Ｓ_０は、特定位置のビットが０である場合に対応するＱＡＭ変調コンスタレーションポイントを指し、Ｓ_１は、特定位置のビットが１である場合に対応するＱＡＭ変調コンスタレーションポイントを指す。Ｓは、ＱＡＭ変調に含まれる全てのコンスタレーションポイントを表す。 Here, S ₀ indicates the QAM modulation constellation point corresponding to the case where the bit at the specific position is 0, and S ₁ indicates the QAM modulation constellation point corresponding to the case where the bit at the specific position is 1. . S represents all constellation points included in the QAM modulation.

さらに、上記の数式６におけるＰ（ｙ_１（１），ｙ_１（２）／ｘ_１，ｘ_２）から導出することで、下記の数式７を得ることができる。
Furthermore, the following formula 7 can be obtained by deriving from P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) in the above formula 6.

ここで、Ｐ（ｙ_１（１）／ｘ_１，ｘ_２）は、下記の数式８によって算出できる。
ここで、Ｎ_０は、雑音の電力スペクトル密度を代表する。 Here, P (y ₁ (1) / x ₁ , x ₂ ) can be calculated by Equation 8 below.
Here, N ₀ represents the power spectral density of noise.

また、Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）の計算方法は、中継局の受信した第２混合信号に対する処理方式と関係があり、後文で詳しく説明する。 The calculation method of P (y ₁ (2) / x ₁ , x ₂ ) is related to the processing method for the second mixed signal received by the relay station, and will be described in detail later.

上記の方法から分かるように、隣接する基地局の間に中継局を導入し、中継局が、移動端末からの信号を受信した後、受信された信号を処理してから、自局に隣接する基地局へ転送するようにすることにより、基地局は、中継局から転送された移動端末からの信号と、直接に移動端末から受信された信号とに対して、統合復号化を行って、自局の所要データを得ることができる。これにより、セル間干渉の問題を効果的に解決し、セル端ユーザのスループットを向上させる。 As can be seen from the above method, a relay station is introduced between adjacent base stations, and after the relay station receives a signal from the mobile terminal, it processes the received signal and then adjoins its own station. By making the transfer to the base station, the base station performs joint decoding on the signal from the mobile terminal transferred from the relay station and the signal directly received from the mobile terminal, and automatically performs the decoding. The required data of the station can be obtained. This effectively solves the problem of inter-cell interference and improves the throughput of cell edge users.

以下、具体的な実施例を参照しながら、上記方法における中継局ＲＳの受信した第２混合信号に対する処理方法、および、第１基地局ＢＳ１が第１混合信号と第３混合信号とに基づいて統合復号化を行う方法について、詳しく説明する。 Hereinafter, based on the processing method for the second mixed signal received by the relay station RS in the above method and the first base station BS1 based on the first mixed signal and the third mixed signal, with reference to a specific embodiment A method for performing unified decoding will be described in detail.

（実施例１）
本実施例において、中継局は、受信された第２混合信号に対して、増幅処理を行ってから転送する。つまり、本実施例において、中継局は、数式Ｘ_ｒ＝α・Ｙ_ｒによって、受信された第２混合信号を処理し、ここでのαは、中継局の電力増幅因子であり、αの設定について、中継局の電力制限を満足することのみを考慮してもよく、移動端末と中継局との間の最適な電力割当を実現するように、移動端末の電力を同時に考慮してもよい。 Example 1
In this embodiment, the relay station performs amplification processing on the received second mixed signal and then transfers it. That is, in the present embodiment, the relay station processes the received second mixed signal by the formula X _r = α · Y _r , where α is a power amplification factor of the relay station, and α is set. May consider only satisfying the power limit of the relay station, or may consider the power of the mobile terminal at the same time so as to realize the optimal power allocation between the mobile terminal and the relay station.

この場合、第１基地局ＢＳ１で取得できる信号は、ｙ_１（１）＝ｈ_１１ｘ_１＋ｈ_２１ｘ_２＋ｚ_１とｙ_１（２）＝ｇ_３ｘ_ｒ＋ｚ_１とを含み、ここで、ｘ_ｒ＝α・ｙ_ｒ＝α・ｇ_１ｘ_１＋α・ｇ_２ｘ_２＋α・ｚ_ｒである。 In this case, the signals obtainable by the first base station BS1 include y ₁ (1) = h ₁₁ x ₁ + h ₂₁ x ₂ + z ₁ and y ₁ (2) = g ₃ x _r + z ₁ , where x _r = α · y _r = α · g ₁ x ₁ + α · g ₂ x ₂ + α · z _r

第１移動端末ＭＳ１と第２移動端末ＭＳ２で採用されているのがＱＡＭ変調方式であれば、上記の数式７におけるＰ（ｙ_１（２）／ｘ_１，ｘ_２）は下記の数式９によって算出できると決定できる。
If the first mobile terminal MS1 and the second mobile terminal MS2 adopt the QAM modulation method, P (y ₁ (2) / x ₁ , x ₂ ) in the above equation 7 is expressed by the following equation 9. It can be determined that it can be calculated.

本実施例では、第１基地局ＢＳ１は、上記の数式８と９によって、ＬＬＲ（ｂ１）とＬＬＲ（ｂ２）を算出すると、算出されたＬＬＲ（ｂ１）とＬＬＲ（ｂ２）を復号器に送信でき、復号化によって、オリジナルデータ情報Ｘ_１を得ることができる。 In the present embodiment, the first base station BS1 calculates the LLR (b1) and the LLR (b2) according to the above formulas 8 and 9, and transmits the calculated LLR (b1) and LLR (b2) to the decoder. can, by the decoding, it is possible to obtain the original data information X _1.

（実施例２）
本実施例において、中継局は、まず、受信された第２混合信号に対して、雑音除去処理を行い、次に、再変調してから転送する。 (Example 2)
In the present embodiment, the relay station first performs noise removal processing on the received second mixed signal, and then remodulates and transfers the second mixed signal.

本実施例における雑音除去処理は、下記の数式１０によって実現できる。
The noise removal processing in the present embodiment can be realized by the following Expression 10.

ここで、Ｓ^（１）とＳ^（２）は、第１移動端末ＭＳ１と第２移動端末ＭＳ２で採用されている変調コンスタレーションをそれぞれ表し、Ｓ_ｍｉｎ ^（１）とＳ_ｍｉｎ ^（２）は、中継局で推定された、第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信されたシンボルをそれぞれ代表する。 Here, S ⁽¹⁾ and S ⁽²⁾ represent the modulation constellations adopted by the first mobile terminal MS1 and the second mobile terminal MS2, respectively, and S _min ⁽¹⁾ and S _min ⁽²⁾ are The symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 estimated by the relay station are respectively representative.

具体的に、第１移動端末ＭＳ１と第２移動端末ＭＳ２がいずれもＱＡＭ変調方式を採用する場合、
が満たされる。 Specifically, when both the first mobile terminal MS1 and the second mobile terminal MS2 adopt the QAM modulation scheme,
Is satisfied.

中継局は、
を得た後、
に基づいて、受信された第２混合信号における第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信されたシンボルのコンスタレーション内の位置
を決定でき、それから、例えば１６ＱＡＭのような、Ｓ^（１）とＳ^（２）よりも高次な変調コンスタレーションを利用して、受信された第２混合信号を再変調し、ｘ_ｒを生成して転送する。 The relay station
After getting
The positions in the constellation of symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 in the received second mixed signal
And then remodulate the received second mixed signal using a higher order modulation constellation than S ⁽¹⁾ and S ⁽²⁾ , eg, 16QAM, to generate x _r And transfer.

このとき、ｘ_ｒは、下記の数式１１によって生成できる。
ここで、
である。 In this case, _{x r} can be generated by Equation 11 below.
here,
It is.

この場合、上記の数式７におけるＰ（ｙ_１（１）／ｘ_１，ｘ_２）は上記の数式８によって算出でき、Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）は下記の数式１２によって算出できると決定できる。
In this case, P (y ₁ (1) / x ₁ , x ₂ ) in Equation 7 can be calculated by Equation 8 above, and P (y ₁ (2) / x ₁ , x ₂ ) can be calculated by Equation 12 below. It can be determined that it can be calculated by

本実施例では、第１基地局ＢＳ１は、上記の数式８と１２によって、ＬＬＲ（ｂ１）とＬＬＲ（ｂ２）を算出すると、算出されたＬＬＲ（ｂ１）とＬＬＲ（ｂ２）を復号器に送信でき、オリジナルデータ情報を得ることができる。 In the present embodiment, the first base station BS1 calculates the LLR (b1) and the LLR (b2) according to the above formulas 8 and 12, and transmits the calculated LLR (b1) and LLR (b2) to the decoder. The original data information can be obtained.

（実施例３）
本実施例において、中継局は、まず、受信された第２混合信号に対して、雑音除去処理を行い、次に、処理後の第２混合信号を圧縮して、最後に転送する。 (Example 3)
In the present embodiment, the relay station first performs noise removal processing on the received second mixed signal, then compresses the processed second mixed signal and finally transfers it.

当業者は、移動端末から基地局へのダイレクトリンクのチャネル条件が十分によい場合、基地局は、第１タイムスロットで受信された第１混合信号から一部の情報を取得することがまだ可能であり、そのため、このとき、実施例２における方法を採用して、２つのＱＡＭ信号からなる第２混合信号を１６ＱＡＭに変調してから送信すれば、やはりたくさんのリソースを浪費してしまう、ということを理解できる。上記の要因を考慮すれば、本実施例では、雑音除去後の信号をさらに圧縮してもよい。具体的に、雑音除去後の信号における第１移動端末ＭＳ１と第２移動端末ＭＳ２から送信された信号のコンスタレーション内の位置
に基づいて、更なるコンスタレーションマッピングを行って、送信しようとする信号ｘ_ｒを得ることにより、送信リソースの消耗を減少させるようにしてもよい。 A person skilled in the art can still obtain some information from the first mixed signal received in the first time slot if the channel condition of the direct link from the mobile terminal to the base station is good enough Therefore, at this time, if the method in the second embodiment is employed and the second mixed signal composed of two QAM signals is modulated to 16 QAM and then transmitted, a lot of resources are wasted. I understand that. In consideration of the above factors, in this embodiment, the signal after noise removal may be further compressed. Specifically, the position in the constellation of the signals transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 in the signal after noise removal
Further, constellation mapping may be performed to obtain a signal _xr to be transmitted, thereby reducing the consumption of transmission resources.

本実施例では、上記のコンスタレーションマッピングは、下記の数式１３によって完成できる。
In the present embodiment, the above constellation mapping can be completed by the following Expression 13.

この場合、上記の数式７におけるＰ（ｙ_１（１）／ｘ_１，ｘ_２）は上記の数式８によって算出でき、Ｐ（ｙ_１（２）／ｘ_１，ｘ_２）は上記の数式１２によって算出できると決定できる。 In this case, P (y ₁ (1) / x ₁ , x ₂ ) in Equation 7 can be calculated by Equation 8 above, and P (y ₁ (2) / x ₁ , x ₂ ) can be calculated from Equation 12 above. It can be determined that it can be calculated by

（実施例４）
本実施例において、中継局は、中継局と基地局との間のチャネル条件に基づいて、上記の実施例１〜実施例３に係る方式を適応的に選択して、受信された第２混合信号を処理することができる。 Example 4
In the present embodiment, the relay station adaptively selects the schemes according to the above first to third embodiments based on the channel condition between the relay station and the base station, and receives the received second mixed signal. The signal can be processed.

本実施例において、図３に示すように、中継局が処理方式を適応的に選択する処理フローは、主に、下記のステップを含む。 In the present embodiment, as shown in FIG. 3, the processing flow in which the relay station adaptively selects the processing method mainly includes the following steps.

ステップ３０１で、中継局と基地局との間のチャネル条件に基づいて、受信された第２混合信号に対して雑音除去処理を行う必要があるかどうかを判断し、受信された第２混合信号に対して雑音除去処理を行う必要がある場合、ステップ３０３を実行し、受信された第２混合信号に対して雑音除去処理を行う必要がない場合、ステップ３０２を実行する。 In step 301, based on the channel condition between the relay station and the base station, it is determined whether it is necessary to perform noise removal processing on the received second mixed signal, and the received second mixed signal If it is necessary to perform a noise removal process on Step 1, Step 303 is executed. If it is not necessary to perform a noise removal process on the received second mixed signal, Step 302 is executed.

具体的に、ＵＥと中継局との間の距離と、ＵＥの送信電力とに基づいて、受信された第２混合信号に対して雑音除去処理を行う必要があるかどうかを判断してもよい。 Specifically, based on the distance between the UE and the relay station and the transmission power of the UE, it may be determined whether it is necessary to perform a noise removal process on the received second mixed signal .

ステップ３０２で、受信された第２混合信号を増幅してから、自局に隣接する基地局に転送する。 In step 302, the received second mixed signal is amplified and then transferred to a base station adjacent to the own station.

本ステップでは、受信された第２混合信号を増幅する方法について、上記の実施例１に記載された方法を参照してよい。 In this step, the method described in the first embodiment may be referred to for the method of amplifying the received second mixed signal.

ステップ３０３で、受信された第２混合信号に対して雑音除去処理を行ってから、ステップ３０４を実行する。 In step 303, noise removal processing is performed on the received second mixed signal, and then step 304 is executed.

本ステップでは、第２混合信号に対して雑音除去処理を行う方法について、上記の実施例２に記載された方法を参照してよい。 In this step, the method described in the second embodiment may be referred to for the method of performing the noise removal process on the second mixed signal.

ステップ３０４で、中継局と基地局との間のチャネル条件に基づいて、雑音除去処理後の第２混合信号を圧縮する必要があるかどうかを判断し、雑音除去処理後の第２混合信号を圧縮する必要がある場合、ステップ３０５を実行し、雑音除去処理後の第２混合信号を圧縮する必要がない場合、ステップ３０６を実行する。 In step 304, based on the channel condition between the relay station and the base station, it is determined whether the second mixed signal after the noise removal processing needs to be compressed, and the second mixed signal after the noise removal processing is If it is necessary to compress, step 305 is executed. If it is not necessary to compress the second mixed signal after the noise removal processing, step 306 is executed.

具体的に、ＵＥと中継局との間の距離と、ＵＥの送信電力とに基づいて、受信された第２混合信号を圧縮する必要があるかどうかを判断してもよい。 Specifically, whether the received second mixed signal needs to be compressed may be determined based on the distance between the UE and the relay station and the transmission power of the UE.

ステップ３０５で、雑音除去処理後の第２混合信号を圧縮してから、圧縮後の信号を、自局に隣接する基地局に転送する。 In step 305, after compressing the second mixed signal after the noise removal processing, the compressed signal is transferred to the base station adjacent to the own station.

本ステップでは、雑音除去処理後の第２混合信号を圧縮する方法について、上記の実施例３に記載された方法を参照してよい。 In this step, the method described in the third embodiment may be referred to for the method of compressing the second mixed signal after the noise removal processing.

ステップ３０６で、雑音除去処理後の第２混合信号を再変調してから、自局に隣接する基地局に転送する。 In step 306, the second mixed signal after the noise removal processing is remodulated and then transferred to the base station adjacent to the own station.

本ステップでは、雑音除去処理後の第２混合信号を再変調する方法について、上記の実施例２に記載された方法を参照してよい。 In this step, for the method of remodulating the second mixed signal after the noise removal processing, the method described in the second embodiment may be referred to.

このような中継局が処理方式を適応的に選択する場合、基地局も、上記の数式７におけるＰ（ｙ_１（１）／ｘ_１，ｘ_２）とＰ（ｙ_１（２）／ｘ_１，ｘ_２）の計算方法を適応的に決定することができる。 When such a relay station adaptively selects a processing method, the base station also uses P (y ₁ (1) / x ₁ , x ₂ ) and P (y ₁ (2) / x ₁ in Equation 7 above. , X ₂ ) can be adaptively determined.

上記のセル間干渉除去方法に対応して、本発明の実施例では、上記方法を実現する中継局および基地局も提供されている。 Corresponding to the above-described inter-cell interference cancellation method, an embodiment of the present invention also provides a relay station and a base station that implement the above method.

図４は、本発明の実施例に係る中継局の内部構成を示す。図４に示すように、本発明の実施例に係る中継局は、第１タイムスロットで、移動端末からの信号を受信する混合信号受信手段と、受信された信号に対して、ネットワーク符号化に基づく処理を行う混合信号処理手段と、第２タイムスロットで、処理後の信号を、自局に隣接する基地局に転送する混合信号転送手段と、を含む。 FIG. 4 shows an internal configuration of the relay station according to the embodiment of the present invention. As shown in FIG. 4, the relay station according to the embodiment of the present invention includes a mixed signal receiving unit that receives a signal from a mobile terminal in a first time slot, and performs network coding on the received signal. Mixed signal processing means for performing processing based on the received signal and mixed signal transfer means for transferring the processed signal to a base station adjacent to the own station in a second time slot.

ここで、上記の混合信号処理手段は、上記の実施例１〜４に係る方法のうちの１つを採用して、受信された信号を処理することができる。つまり、上記の混合信号処理手段は、上記の実施例１に係る方法を採用して、受信された信号に対して増幅処理を行う増幅モジュールを含んでよい。あるいは、上記の混合信号処理手段は、上記の実施例２に係る方法を採用して、受信された信号に対して雑音除去処理と再変調処理とをそれぞれ行う雑音除去モジュールと変調モジュールとを含んでよい。またあるいは、上記の混合信号処理手段は、上記の実施例３に係る方法を採用して、受信された信号に対して雑音除去処理と圧縮処理とをそれぞれ行う雑音除去モジュールと圧縮モジュールとを含んでよい。 Here, the mixed signal processing means can process the received signal by employing one of the methods according to the first to fourth embodiments. That is, the mixed signal processing means may include an amplification module that performs the amplification process on the received signal by employing the method according to the first embodiment. Alternatively, the mixed signal processing means includes a noise removal module and a modulation module that perform a noise removal process and a remodulation process on the received signal by employing the method according to the second embodiment. It's okay. Alternatively, the mixed signal processing means includes a noise removal module and a compression module that perform a noise removal process and a compression process on the received signal by employing the method according to the third embodiment. It's okay.

図５は、本発明の実施例に係る基地局の内部構成を示す。図５に示すように、本発明の実施例に係る基地局は、第１タイムスロットで直接に移動端末から受信された混合信号と、第２タイムスロットで中継局から受信された混合信号とに対して、統合検出を行って、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比を得る統合検出手段と、自局のカバー範囲内の移動端末から送信された信号に含まれる各ビットの対数尤度比に基づいて、復号化を行って、自局のカバー範囲内の移動端末から送信された信号を得る復号器と、を含む。 FIG. 5 shows an internal configuration of the base station according to the embodiment of the present invention. As shown in FIG. 5, the base station according to the embodiment of the present invention converts the mixed signal received directly from the mobile terminal in the first time slot and the mixed signal received from the relay station in the second time slot. On the other hand, integrated detection means for performing integrated detection and obtaining a log-likelihood ratio of each bit included in a signal transmitted from a mobile terminal within the coverage range of the local station, and from a mobile terminal within the coverage range of the local station A decoder that performs decoding based on the log likelihood ratio of each bit included in the transmitted signal to obtain a signal transmitted from a mobile terminal within the coverage of the local station.

ここで、上記の統合検出手段は、上記の実施例１〜４に係る方法を採用して、第１タイムスロットで直接に移動端末から受信された混合信号と、第２タイムスロットで中継局から受信された混合信号とに対して、統合検出を行うことができる。 Here, the integrated detection means adopts the method according to the first to fourth embodiments, and receives the mixed signal received from the mobile terminal directly in the first time slot and the relay station in the second time slot. Integrated detection can be performed on the received mixed signal.

以下、中継局を有しない従来の無線通信システムおよび本発明の実施例で提供されているいくつかの方法の、信号対雑音比（ＳＮＲ）が等価する場合のブロック誤り率をシミュレーションすることにより、本発明の実施例で提供されているセル間干渉除去方法の性能を詳しく説明する。今回のシミュレーションで採用されたシミュレーションパラメータは、下記の表１に示す通りである。 Hereinafter, by simulating the block error rate when the signal-to-noise ratio (SNR) is equivalent for the conventional wireless communication system without a relay station and some methods provided in the embodiments of the present invention, The performance of the inter-cell interference cancellation method provided in the embodiment of the present invention will be described in detail. The simulation parameters employed in this simulation are as shown in Table 1 below.

図６（ａ）と図６（ｂ）は、中継局と移動端末との間の距離が１０メートルと５０メートルであるとき、中継局を有しない場合および本発明の実施例１〜３に係る方法を採用する場合の信号対雑音比（ＳＮＲ）とブロック誤り率（ＢＬＥＲ）との関係をそれぞれ示す。図６（ａ）と図６（ｂ）において、四角印の曲線に対応するのは、中継局を有しない場合のＳＮＲとＢＬＥＲとの関係であり、丸印の曲線に対応するのは、本発明の実施例１に係る方法を採用する場合のＳＮＲとＢＬＥＲとの関係であり、十字印の曲線に対応するのは、本発明の実施例２に係る方法を採用する場合のＳＮＲとＢＬＥＲとの関係であり、三角印の曲線に対応するのは、本発明の実施例３に係る方法を採用する場合のＳＮＲとＢＬＥＲとの関係である。図６（ａ）と図６（ｂ）から分かるように、異なる信号対雑音比の条件においても、本発明で提供されているセル間干渉除去方法は、中継局を有しない従来の構成より優れている。 6 (a) and 6 (b) show the case where the distance between the relay station and the mobile terminal is 10 meters and 50 meters, the case where there is no relay station, and the first to third embodiments of the present invention. The relationship between the signal-to-noise ratio (SNR) and the block error rate (BLER) when the method is employed is shown. In FIG. 6A and FIG. 6B, the square curve corresponds to the relationship between SNR and BLER when no relay station is provided, and the circle curve corresponds to this curve. The relationship between SNR and BLER when the method according to the first embodiment of the invention is adopted, and the curve corresponding to the cross mark corresponds to the SNR and BLER when the method according to the second embodiment of the present invention is adopted. The relationship between the SNR and the BLER when the method according to the third embodiment of the present invention is employed corresponds to the curve indicated by the triangle mark. As can be seen from FIG. 6A and FIG. 6B, the inter-cell interference cancellation method provided in the present invention is superior to the conventional configuration without a relay station even under different signal-to-noise ratio conditions. ing.

上記の構成をさらに完備するために、本発明の実施例では、統合データ転送を行う移動端末ペアを如何に選択するか、即ち、前記第１移動端末と第２移動端末とを如何に選択するかという方法も提供されている。該方法は、基地局と移動端末とによって協同して実行することができる。図７に示すように、その具体的なフローは、主に、下記のステップを含む。 In order to further complete the above configuration, in the embodiment of the present invention, how to select a mobile terminal pair for performing integrated data transfer, that is, how to select the first mobile terminal and the second mobile terminal. There is also a way to do this. The method can be performed cooperatively by the base station and the mobile terminal. As shown in FIG. 7, the specific flow mainly includes the following steps.

ステップ７０１で、移動端末は、本セルと隣接セルの基準信号を測定する。 In step 701, the mobile terminal measures the reference signals of this cell and the neighboring cells.

ステップ７０２で、本セルと隣接セルの基準信号強度の差が所定の基準信号閾値より小さい場合、該移動端末は、本セルの基地局へ、隣接セルのアイデンティティ（ＩＤ）と本セルの直送リンクのチャネル条件とを報告する。 If the difference between the reference signal strengths of the cell and the neighboring cell is smaller than a predetermined reference signal threshold in step 702, the mobile terminal transmits the identity (ID) of the neighboring cell and the direct transmission link of the cell to the base station of the cell. Report channel conditions.

ステップ７０３で、基地局は、移動端末に対し、転送リンクを介して転送された本セルの基準信号を測定するよう通知する。 In step 703, the base station notifies the mobile terminal to measure the reference signal of this cell transferred through the transfer link.

ステップ７０４で、移動端末は、測定して得られた、転送リンクを介して転送された本セルの基準信号から、転送リンクのチャネル条件を得、転送リンクのチャネル条件を本セルの基地局へ報告する。 In step 704, the mobile terminal obtains the channel condition of the transfer link from the reference signal of the main cell transferred through the transfer link obtained by measurement, and transmits the channel condition of the transfer link to the base station of the main cell. Report.

ステップ７０５で、本セルの直送リンクのチャネル条件と転送リンクのチャネル条件とに基づいて、転送リンクの品質が直送リンクより優れているかどうかを判断し、転送リンクの品質が直送リンクより優れている場合、該移動端末を候補リストに追加する。 In step 705, based on the channel condition of the direct link of this cell and the channel condition of the transfer link, it is determined whether the quality of the transfer link is better than the direct link, and the quality of the transfer link is superior to the direct link. The mobile terminal is added to the candidate list.

ステップ７０６で、自局の候補リスト中の１つの移動端末と、隣接セルの候補リスト中の１つの移動端末とをランダムに選択して、統合データ転送を行う移動端末ペアとする。 In step 706, one mobile terminal in the candidate list of the local station and one mobile terminal in the candidate list of the neighboring cell are selected at random to form a mobile terminal pair that performs integrated data transfer.

具体的に、上記の本セルの直送リンクのチャネル条件および転送リンクのチャネル条件は、直送リンクを介して受信されたパイロット信号の強度と、転送リンクを介して受信されたパイロット信号の強度とによって表すことができ、例えば、転送リンクを介して受信されたパイロット信号の強度が、直送リンクを介して受信されたパイロット信号の強度より大きい場合、該移動端末を候補リストに追加することができる。 Specifically, the channel conditions of the direct link and the transfer link of the cell are determined by the strength of the pilot signal received via the direct link and the strength of the pilot signal received via the transfer link. For example, if the strength of the pilot signal received over the forward link is greater than the strength of the pilot signal received over the direct link, the mobile terminal can be added to the candidate list.

本発明の実施例では、統合データ転送を行う移動端末ペアを選択するほかの方法も提供されている。該方法は、基地局と中継局とによって協同して実行することができる。図８に示すように、その具体的なフローは、主に、下記のステップを含む。 Embodiments of the present invention also provide other methods of selecting a mobile terminal pair for integrated data transfer. The method can be performed cooperatively by the base station and the relay station. As shown in FIG. 8, the specific flow mainly includes the following steps.

ステップ８０１で、中継局は、隣接セルの移動端末から送信された基準信号を監視する。 In step 801, the relay station monitors a reference signal transmitted from a mobile terminal in an adjacent cell.

ステップ８０２で、２つのセルの移動端末からの基準信号の強度の差が所定の第１閾値より小さくて、かつ、上記２つのセルの移動端末からの基準信号の強度がいずれも所定の第２閾値より大きい場合、中継局は、上記の２つのセルの移動端末からの基準信号のフォーマットを、上記２つのセルの基地局へ通知する。 In step 802, the difference between the reference signal strengths from the mobile terminals in the two cells is smaller than a predetermined first threshold value, and the reference signal strengths from the mobile terminals in the two cells are both predetermined second values. When larger than a threshold value, a relay station notifies the format of the reference signal from the mobile terminal of said 2 cell to the base station of said 2 cell.

説明すべきものとして、上記の第１閾値と第２閾値は、経験値に基づいて、予め設定してもよい。 As to be described, the first threshold value and the second threshold value may be set in advance based on experience values.

ステップ８０３で、上記２つのセルの基地局は、受信された基準信号のフォーマットに基づいて、上記２つのセルの移動端末のＩＤをそれぞれ決定して、該ＩＤに対応する移動端末を自局の候補リストに追加する。 In step 803, the base stations of the two cells determine the IDs of the mobile terminals of the two cells based on the format of the received reference signal, respectively, and determine the mobile terminals corresponding to the IDs of their own stations. Add to the candidate list.

ステップ８０４で、自局の候補リスト中の１つの移動端末と、隣接セルの候補リスト中の１つの移動端末とをランダムに選択して、統合データ転送を行う移動端末ペアとする。 In step 804, one mobile terminal in the candidate list of the local station and one mobile terminal in the candidate list of the neighboring cell are selected at random to form a mobile terminal pair that performs integrated data transfer.

上記の図７と図８に示す方法によって、統合データ転送を行う移動端末ペアを決定することができる。統合データ転送を行う移動端末ペアを決定した後、即ち、第１移動端末と第２移動端末とを決定した後、システムにおける中継局は、上記の実施例における方法を利用して、受信された第１移動端末と第２移動端末からの信号に対して、ネットワーク符号化に基づく処理を行ってから、自局に隣接する基地局へ転送することができる。続いて、基地局は、それぞれ、中継局から転送された信号と、直接に上記の第１移動端末と第２移動端末から受信された信号とに対して、統合復号化を行って、自局の所要データを得る。 The mobile terminal pair that performs integrated data transfer can be determined by the method shown in FIGS. After determining the mobile terminal pair to perform the integrated data transfer, that is, after determining the first mobile terminal and the second mobile terminal, the relay station in the system is received using the method in the above embodiment. The signal from the first mobile terminal and the second mobile terminal can be transferred to a base station adjacent to the own station after performing processing based on network coding. Subsequently, the base station performs joint decoding on the signal transferred from the relay station and the signals directly received from the first mobile terminal and the second mobile terminal, respectively, Get the required data.

上記の説明から分かるように、上記の実施例はいずれも、隣接する基地局の間に中継局を設けることにより、干渉除去を実現するものである。実際の応用では、ネットワークに中継局が設けられなくても、一時的に空いている隣接基地局を利用して、それを上記の中継局として、受信された移動端末からの信号に対して、ネットワーク符号化に基づく処理を行ってから、隣接基地局へ転送するようにしてもよい。これにより、本発明に係る干渉除去方法を実現する。図９は、ネットワークトポロジーを示す図である。図９に示すネットワークにおいて、ＢＳ１とＢＳ２は２つの隣接する基地局であり、ここで、ＢＳ１は、移動端末ＭＳ１のサービング基地局であり、ＢＳ２は、移動端末ＭＳ２のサービング基地局である。ＢＳ３は、ＢＳ１とＢＳ２のいずれにも隣接する基地局であり、かつ、ＢＳ３は、サービスを必要とする移動端末がなく、あるいは、一時的に比較的に空いている。この場合、ＢＳ３を中継局として機能するように設定してもよい。つまり、第１ステップで、ＢＳ３は、第１タイムスロットで、自局に隣接する基地局ＢＳ１とＢＳ２のカバー範囲内の移動端末ＭＳ１とＭＳ２から送信された信号を受信し、第２ステップで、ＢＳ３は、受信された信号に対して、ネットワーク符号化に基づく処理を行い、最後に、第３ステップで、ＢＳ３は、第２タイムスロットで、処理後の信号を、自局に隣接する基地局ＢＳ１とＢＳ２に転送する。このようにして、基地局ＢＳ１とＢＳ２は、それぞれ、ＢＳ３から転送された移動端末ＭＳ１とＭＳ２からの信号と、直接に移動端末ＭＳ１とＭＳ２から受信された信号とに対して、統合復号化を行って、自局の所要データを得ることができる。これにより、セル間干渉の問題を効果的に解決し、セル端ユーザのスループットを向上させる。 As can be seen from the above description, in any of the above embodiments, interference cancellation is realized by providing a relay station between adjacent base stations. In actual application, even if a relay station is not provided in the network, a neighboring base station that is temporarily vacant is used as a relay station for the received signal from the mobile terminal, You may make it transfer to an adjacent base station, after performing the process based on network coding. Thereby, the interference removal method according to the present invention is realized. FIG. 9 is a diagram illustrating a network topology. In the network shown in FIG. 9, BS1 and BS2 are two adjacent base stations, where BS1 is a serving base station for mobile terminal MS1 and BS2 is a serving base station for mobile terminal MS2. BS3 is a base station adjacent to both BS1 and BS2, and BS3 has no mobile terminal that requires service or is temporarily relatively free. In this case, BS3 may be set to function as a relay station. That is, in the first step, BS3 receives signals transmitted from the mobile terminals MS1 and MS2 within the coverage of the base stations BS1 and BS2 adjacent to the own station in the first time slot, and in the second step, BS3 performs a process based on the network coding on the received signal. Finally, in the third step, BS3 transmits the processed signal in the second time slot to the base station adjacent to the own station. Transfer to BS1 and BS2. In this way, the base stations BS1 and BS2 respectively perform joint decoding on the signals from the mobile terminals MS1 and MS2 transferred from the BS3 and the signals directly received from the mobile terminals MS1 and MS2. The necessary data of the local station can be obtained. This effectively solves the problem of inter-cell interference and improves the throughput of cell edge users.

このような応用シナリオで、図７と同じ方法、あるいは、図８と類似する方法を採用して、統合データ転送を行う移動端末ペアＭＳ１とＭＳ２とを選択してもよい。説明すべきものとして、図８と類似する方法を採用する場合、中継局に代わって、現時点で空いている基地局によって、図８に示す方法における中継局の機能を実現すればよい。 In such an application scenario, the mobile terminal pair MS1 and MS2 that perform integrated data transfer may be selected by adopting the same method as in FIG. 7 or a method similar to that in FIG. As a matter of explanation, when a method similar to that in FIG. 8 is adopted, the function of the relay station in the method shown in FIG. 8 may be realized by a base station that is currently available instead of the relay station.

上記の構成によれば、ネットワークに中継局が設けられなくても、一時的に比較的に空いている基地局を利用して、中継局の機能を実現することができる。これにより、セル間干渉の問題を効果的に解決し、セル端ユーザのスループットを向上させる。 According to said structure, even if a relay station is not provided in a network, the function of a relay station is realizable using the base station temporarily comparatively vacant. This effectively solves the problem of inter-cell interference and improves the throughput of cell edge users.

上記は、本発明の好ましい実施例にすぎず、本発明を限定するものではない。本発明の精神と原則内で行われる種々の修正、均等置換え、改善などは全て本発明の保護範囲内に含まれるべきである。 The above are only preferred embodiments of the present invention and do not limit the present invention. Various modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present invention should all be included in the protection scope of the present invention.

Claims

An inter-cell interference cancellation method,
The relay station receives the signal transmitted from the mobile terminal within the coverage of the base station adjacent to the relay station in the first time slot,
The relay station performs processing based on network coding on the received signal,
The relay station transfers the processed signal to the base station adjacent to the own station in the second time slot.
A method comprising:

The relay station performs processing based on network coding on the received signal,
The relay station performs amplification processing on the received signal;
The method of claim 1 comprising:

The relay station performs processing based on network coding on the received signal,
The relay station performs noise removal and remodulation processing on the received signal.
The method of claim 1 comprising:

The relay station performs processing based on network coding on the received signal,
The relay station performs noise removal processing and compression processing on the received signal.
The method of claim 1 comprising:

The relay station performs processing based on network coding on the received signal,
Based on the channel conditions between the relay station and the base station, it is necessary to determine whether it is necessary to perform noise removal processing on the received signal and to perform noise removal processing on the received signal. In some cases, after performing noise removal processing on the received signal, Step B is executed, and when it is not necessary to perform noise removal processing on the received signal, Step A is performed to amplify the received signal. When,
Based on the channel conditions between the relay station and the base station, it is determined whether or not the signal after the noise removal processing needs to be compressed. If the signal after the noise removal processing needs to be compressed, the noise removal processing is performed. Step B for re-modulating the signal after the noise removal processing when the later signal is compressed and the signal after the noise removal processing does not need to be compressed;
The method of claim 1 comprising:

The base station receives the signal transmitted from the mobile terminal within the coverage of the base station and the base station adjacent to the base station in the first time slot,
The base station receives the processed signal transmitted from the relay station in the second time slot,
Based on the signal received by the base station in the first time slot and the signal received in the second time slot, the base station performs joint decoding, and the signal transmitted from the mobile terminal within the coverage of the base station Get the
The method of claim 1 further comprising:

Based on the signal received by the base station in the first time slot and the signal received in the second time slot, the base station performs joint decoding,
First, the base station receives the signal transmitted from the mobile station within the coverage of the base station adjacent to the base station and the base station received by the base station in the first time slot, and the relay received in the second time slot. Perform integrated detection on the processed signal transmitted from the station to obtain the log likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage of the local station, Decoding with a decoder to obtain a signal transmitted from a mobile terminal within the coverage of its own station,
The method of claim 6 comprising:

The relay station performing a process based on network coding on the received signal includes the relay station performing an amplification process on the received signal;
The integrated detection is performed by the base station using a mathematical formula.
Obtaining a log likelihood ratio of each bit included in a signal transmitted from a mobile terminal within the coverage of the local station,
Here, P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) = P (y ₁ (1) / x ₁ , x ₂ ) · P (y ₁ (2) / x ₁ , x ₂ ), and P (y ₁ (1) / x ₁ , x ₂ ), P (y ₁ (2) / x ₁ , x ₂ )
,
Y ₁ (1) represents the first mixed signal received by the first base station BS1 in the first time slot, and y ₁ (2) represents the first base station BS1 in the second time slot. Representing the received third mixed signal, h ₁₁ represents the signal impulse response of the channel from the first mobile terminal MS1 to the first base station BS1, and h ₂₁ represents the first base station from the second mobile terminal MS2. on behalf of the channel signal impulse response to BS1, _{x 1} and _{x 2} is provided with a first mobile terminal MS1 the second mobile terminal MS2 a signal transmitted by the first time slot representative respectively, _{g 1} and _{g 2} are a first mobile terminal MS1 behalf each channel signal impulse response to the relay station from the second mobile terminal MS2, _{g 3} and _{g 4} is from the relay station to the first base station BS1 second base station BS2 Channel signal imper Scan response representative respectively, N ₀ is representative of the power spectral density of the noise, alpha is the power amplification factor of the repeater station, S ₀ is QAM modulated corresponding to when the bit of a specific position is 0 Refers to the constellation point, S ₁ refers to the QAM modulation constellation point corresponding to the case where the bit at the specific position is 1, and S represents all the constellation points included in the QAM modulation.
The method of claim 7.

The relay station performing a process based on network coding on the received signal includes the relay station performing a noise removal and remodulation process on the received signal;
Here, the noise removal is a mathematical formula.
Realized by
The remodulation process is performed by a relay station,
After getting
Based on the position in the constellation of the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 in the received second mixed signal
Remodulate the received second mixed signal using a higher order modulation constellation than S ⁽¹⁾ and S ⁽²⁾ to generate and transmit x _r , Including
The integrated detection is performed by the base station using a mathematical formula.
Obtaining a log likelihood ratio of each bit included in a signal transmitted from a mobile terminal within the coverage of the local station,
Here, P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) = P (y ₁ (1) / x ₁ , x ₂ ) · P (y ₁ (2) / x ₁ , x ₂ ), and P (y ₁ (1) / x ₁ , x ₂ ), P (y ₁ (2) / x ₁ , x ₂ )
,
Y ₁ (1) represents the first mixed signal received by the first base station BS1 in the first time slot, and y ₁ (2) represents the first base station BS1 in the second time slot. On behalf of the third mixed signal received, y _r is representative of the second mixed signal relay station receives the first time slot, h _11, the channel from the first mobile terminal MS1 to the first base station BS1 on behalf of the signal impulse _{response, h 21,} from the second mobile terminal MS2 behalf of the channel signal impulse response of the first base station BS1, _{x 1} and _{x 2} is provided with a first mobile terminal MS1 second movement On behalf respectively a signal terminal MS2 is transmitted in the first time slot, _{x r} is representative of the second mixed signal after processing, _{g 1} and _{g 2} includes a first mobile terminal MS1 from the second mobile terminal MS2 Signal impulse of channel to relay station Answer was representative respectively, g ₃ is representative of the channel signal impulse response from the relay station to the first base station BS1, N ₀ is representative of the power spectral density of the noise, S _0, the bit of a specific location Indicates the corresponding QAM modulation constellation point when S is 0, S ₁ indicates the corresponding QAM modulation constellation point when the bit at a specific position is 1, and S indicates all the QAM modulation constellation points S ⁽¹⁾ and S ⁽²⁾ represent modulation constellations adopted by the first mobile terminal MS1 and the second mobile terminal MS2, respectively, and S _min ⁽¹⁾ and S _min ^{(2 )} Represents the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 estimated by the relay station, respectively.
The method of claim 7.

The relay station performing a process based on network coding on the received signal includes the relay station performing a noise removal and compression process on the received signal;
Here, the noise removal is a mathematical formula.
Realized by
The compression process is performed by the relay station,
After getting
Based on the position in the constellation of the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 in the received second mixed signal
And then the formula
Performing constellation mapping, generating and forwarding x _r ,
The integrated detection is performed by the base station using a mathematical formula.
Obtaining a log likelihood ratio of each bit included in a signal transmitted from a mobile terminal within the coverage of the local station,
Here, P (y ₁ (1), y ₁ (2) / x ₁ , x ₂ ) = P (y ₁ (1) / x ₁ , x ₂ ) · P (y ₁ (2) / x ₁ , x ₂ ), and P (y ₁ (1) / x ₁ , x ₂ ), P (y ₁ (2) / x ₁ , x ₂ )
,
Y ₁ (1) represents the first mixed signal received by the first base station BS1 in the first time slot, and y ₁ (2) represents the first base station BS1 in the second time slot. On behalf of the third mixed signal received, y _r is representative of the second mixed signal relay station receives the first time slot, h _11, the channel from the first mobile terminal MS1 to the first base station BS1 on behalf of the signal impulse _{response, h 21,} from the second mobile terminal MS2 behalf of the channel signal impulse response of the first base station BS1, _{x 1} and _{x 2} is provided with a first mobile terminal MS1 second movement On behalf respectively a signal terminal MS2 is transmitted in the first time slot, _{x r} is representative of the second mixed signal after processing, _{g 1} and _{g 2} includes a first mobile terminal MS1 from the second mobile terminal MS2 Signal impulse of channel to relay station Answer was representative respectively, g ₃ is representative of the channel signal impulse response from the relay station to the first base station BS1, N ₀ is representative of the power spectral density of the noise, S _0, the bit of a specific location Indicates the corresponding QAM modulation constellation point when S is 0, S ₁ indicates the corresponding QAM modulation constellation point when the bit at a specific position is 1, and S indicates all the QAM modulation constellation points S ⁽¹⁾ and S ⁽²⁾ represent modulation constellations adopted by the first mobile terminal MS1 and the second mobile terminal MS2, respectively, and S _min ⁽¹⁾ and S _min ^{(2 )} Represents the symbols transmitted from the first mobile terminal MS1 and the second mobile terminal MS2 estimated by the relay station, respectively.
The method of claim 7.

Determine the mobile terminal pair to perform integrated data transfer,
The method according to claim 1, further comprising:

Determining a mobile terminal pair that performs the integrated data transfer includes:
The mobile terminal measures the reference signal of this cell and neighboring cells,
When the difference in reference signal strength between this cell and the adjacent cell is smaller than a predetermined reference signal threshold, the mobile terminal reports the ID of the adjacent cell and the channel condition of the direct transmission link of this cell to the base station of this cell. And
The base station notifies the mobile terminal to measure the reference signal of this cell transferred via the transfer link,
The mobile terminal obtains the channel condition of the transfer link from the reference signal of this cell transferred through the transfer link obtained by measurement, and reports the channel condition of the transfer link to the base station of this cell.
Based on the channel condition of the direct link of this cell and the channel condition of the transfer link, it is determined whether the quality of the transfer link is better than that of the direct link. Add device to candidate list,
One mobile terminal in the candidate list of its own station and one mobile terminal in the candidate list of neighboring cells are selected at random to form a mobile terminal pair that performs integrated data transfer.
12. The method of claim 11 comprising:

Determining a mobile terminal pair that performs the integrated data transfer includes:
The relay station monitors the reference signal transmitted from the mobile terminal in the adjacent cell,
When the difference in the strength of the reference signals from the mobile terminals in the two cells is smaller than a predetermined first threshold, and the strengths of the reference signals from the mobile terminals in the two cells are both greater than the predetermined second threshold The relay station notifies the base station of the two cells of the format of the reference signal from the mobile terminal of the two cells,
The base stations of the two cells determine the IDs of the mobile terminals of the two cells based on the format of the received reference signal, and add the mobile terminals corresponding to the IDs to the candidate list of the local station And
One mobile terminal in the candidate list of its own station and one mobile terminal in the candidate list of neighboring cells are selected at random to form a mobile terminal pair that performs integrated data transfer.
12. The method of claim 11 comprising:

The relay station is realized by a currently available base station,
The method according to claim 1.

A relay station,
Mixed signal receiving means for receiving a mixed signal from a mobile terminal in a first time slot;
Mixed signal processing means for performing processing based on network coding on the received mixed signal;
Mixed signal transfer means for transferring the processed mixed signal to the base station adjacent to the own station in the second time slot;
The relay station characterized by including.

A base station,
Mobile terminal within the coverage of its own station by performing integrated detection on the mixed signal received directly from the mobile terminal in the first time slot and the mixed signal received from the relay station in the second time slot Integrated detection means for obtaining a log-likelihood ratio of each bit included in the signal transmitted from
Based on the log-likelihood ratio of each bit included in the signal transmitted from the mobile terminal within the coverage of the local station, decoding is performed to obtain the signal transmitted from the mobile terminal within the coverage of the local station A decoder;
A base station comprising: