JP2004350135A - Radio communication device having delay profile data generation function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relieve a processing burden by minimizing processing required for generation of delay profile data regarding a radio communication device having a delay profile data generation function. <P>SOLUTION: Correlation between received data stored in a received data storage memory 1-1 and known signs is acquired by a matched filter (MF) 1-2, in-phase components of the received data are added together by an in-phase addition part 1-3, converted into power values by a power conversion part 1-4 and the power values are added by a power addition part 1-5. Path detection processing is performed from the delay profile data to which power addition is performed by a path detection processing part 1-6, RAKE composition of the received data is performed based on detected path information by a finger part 1-7, decoding processing of the received data is performed by a received data processing part 1-8, an error rate (BER/BLER) of the received data is judged by a received data judgment part 1-9, in-phase addition frequencies or power addition frequencies are gradually reduced based on receiving characteristics and made into the addition frequencies in which the reception characteristics becomes the minimum permitted limit value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

ここでαはスロット番号を、βはシンボル番号をそれぞれ示す。
【００２３】
パスの信号対雑音比（Ｓ／Ｎ）を高めるのはパイロットシンボル同士の同相加算であり、電力加算は分散を小さくする効果が得られる。パスの信号対雑音比（Ｓ／Ｎ）を高める理由は、正確なパスタイミングを基に復調を行い、受信特性（ＢＥＲ／ＢＬＥＲ）を向上させるためであるが、受信特性が目標の基準を十分満たし、受信特性に余裕がある場合は、パス検出の精度が多少落ちても受信結果に影響を与えない。そこで、パス検出に費やす処理を、受信結果に影響が出ない範囲で削減し、削減した分の処理を他の処理に回す、或いは消費電力の削減を図ることができる。
【００２４】
図３に受信シンボルの信号対干渉電力比（ＳＩＲ）とエラーレート（ＢＥＲ／ＢＬＥＲ）の特性の関係の一例を示す。この特性の関係を基に本発明の実施形態を説明する。本発明の第１の実施形態は、各伝送サービスにおける目標エラーレート（ＢＥＲ／ＢＬＥＲ）に対して、信号対干渉電力比（ＳＩＲ）の設定値が十分に低く、受信特性が良好である場合に、遅延プロファイルデータ生成における電力加算回数を徐々に減少させ、電力加算の処理量を削減する。
【００２５】
或る目標エラーレート（ＢＥＲ／ＢＬＥＲ）に対し、該目標エラーレート（ＢＥＲ／ＢＬＥＲ）が得られる信号対干渉電力比（ＳＩＲ）の範囲を予め測定して決定し設定しておく。図３において、この信号対干渉電力比（ＳＩＲ）の範囲は「ＳＩＲ下限」〜「ＳＩＲ上限」の範囲として表している。
【００２６】
実際の無線通信機の信号対干渉電力比（ＳＩＲ）の設定値が、上記「ＳＩＲ下限」〜「ＳＩＲ上限」の範囲内にある場合、次回の遅延プロファイルデータ生成時における電力加算回数を１回減らす。即ち、前述の式（１）における電力加算回数をｋ−１とする。
【００２７】
その後、遅延プロファイルデータ生成毎に信号対干渉電力比（ＳＩＲ）の設定値を確認し、同様の処理を繰り返す。電力加算回数を減少させるにつれて、遅延プロファイルデータの分散が大きくなるためパス検出の精度が下がり、その結果、受信特性（ＢＥＲ／ＢＬＥＲ）が劣化する。
【００２８】
すると、信号対干渉電力比（ＳＩＲ）の設定値を高くし、通信相手装置に対して送信電力を高めるように要求する電力制御指令を送信する。これを繰り返すことにより、次第に信号対干渉電力比（ＳＩＲ）の設定値が高くなり、図３に示す予め決定された信号対干渉電力比（ＳＩＲ）設定値の上限を超えてしまう。
【００２９】
そして、予め決定された信号対干渉電力比（ＳＩＲ）設定値の上限を超えた時点で、電力加算回数を減少させる動作を停止し、その後は、信号対干渉電力比（ＳＩＲ）の設定値がこの上限付近に落ち着くよう加算回数を増減させる。なお、電力加算回数を増加させる際に、加算回数のデフォルト上限回数ｋを超えないようにする。こうすることにより、遅延プロファイル生成に必要な加算処理を最低限の受信特性を満たす範囲で軽減することができる。
【００３０】
次に本発明の第２の実施形態について説明する。発明の第２の実施形態では、各伝送サービスにおける信号対干渉電力比（ＳＩＲ）の設定値に対し、受信信号の実測エラーレート （ＢＥＲ／ＢＬＥＲ）が十分に良好である場合に、遅延プロファイルデータ生成における電力加算回数を徐々に減少させ、処理量を削減させる。
【００３１】
図３に示すように、信号対干渉電力比（ＳＩＲ）の設定値に対して、受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）の上限及び下限を予め測定し決定しておく。受信信号の実測エラーレート（ＢＥＲ／ＢＬＥＲ）がその上限より低い値となっている場合、電力加算の回数を１回減少させ、次回の遅延プロファイル生成時まで、受信データ判定部１−９において受信データのエラーレート（ＢＥＲ／ＢＬＥＲ）を判定する。
【００３２】
電力加算回数を逓減させるにつれて分散が大きくなり、その結果、パスの検出精度が低下し、エラーレート（ＢＥＲ／ＢＬＥＲ）が上昇する。電力加算回数をデフォルト回数（初期値）より１回ずつ減少させつつ、受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）を監視し、それが前記上限を超えたときに電力加算回数を減少させる動作を停止する。
【００３３】
そして、受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）が該上限より低い値となるまで電力加算回数を増やしていく。つまり、式（１）における電力加算回数ｋの値を変化させることにより、常に受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）は上限値付近の値となり、最低限の受信特性を満たしながら、パスサーチ処理負担が最少となるように軽減することができる。
【００３４】
次に本発明の第３の実施形態について説明する。本発明の第３の実施形態は、遅延プロファイルデータの最大パスの信号対雑音比（Ｓ／Ｎ）を基に、電力加算回数をデフォルト加算回数（初期値）から逓減し、処理量を軽減する。図４に示すように、遅延プロファイルデータの最大パスに対して或る閾値を設け、パスの信号レベルが該閾値を超えている場合に電力加算回数を１回ずつ減少させる。即ち、式（１）の電力加算回数ｋの値を１ずつ減少させる。
【００３５】
電力加算回数を減少させることにより、遅延プロファイルデータの分散が大きくなるため、マルチパスを正確に捕捉することができなくなり、次第に受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）が上昇する。受信特性の劣化は、遅延プロファイルデータの分散値（図４のσ）に対する閾値に基づいて判断する。
【００３６】
遅延プロファイルデータの分散が該閾値よりも大きくならない範囲で電力加算回数を減らしていく。なお、分散の算出に際しては、パスのピーク値の影響をできる限り抑えるために、該閾値を超えるパスに関しては、全て、該閾値をパスの電力値として加算を行う。
【００３７】
この実施形態では、受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）をわざわざ取得することなく、電力加算回数を調整することができるため、伝播状況を敏速に処理へ反映させることができる。なお、電力加算回数を増加する過程で、電力加算回数がデフォルト上限回数ｋを超えないようにする。
【００３８】
次に本発明の第４の実施形態について説明する。本発明の第４の実施形態は、各伝送サービスにおける目標エラーレート（ＢＥＲ／ＢＬＥＲ）に対し、信号対干渉電力比（ＳＩＲ）の設定値が十分に低く、受信特性が良好である場合に、遅延プロファイルデータ生成における同相加算回数を徐々に減少させ、処理量を削減する。
【００３９】
或る目標エラーレート（ＢＥＲ／ＢＬＥＲ）に対し、信号対干渉電力比（ＳＩＲ）の設定値が十分に低い場合、無線データフレームの最終スロット（ｓｌｏｔ ｋ）から順に同相加算の回数を１回ずつ減らしてゆく。最終スロット（ｓｌｏｔ ｋ）の同相加算回数がゼロになった場合は、次に最終スロットの一つ前のスロット（ｓｌｏｔ ｋ−１）から同相加算の回数を１回ずつ減らしてゆく。
【００４０】
同相加算回数を減らすことにより、パスの信号対雑音比（Ｓ／Ｎ）が低下し、次第に受信特性が劣化する。それによって、信号対干渉電力比（ＳＩＲ）の設定値を高くし、通信相手装置に対して送信電力を高めるように要求する電力制御指令を送信する。
【００４１】
信号対干渉電力比（ＳＩＲ）の設定値がその上限を超えた時点で、同相加算回数の逓減を止め、信号対干渉電力比（ＳＩＲ）の設定値が該上限より低い値となるまで同相加算回数を１回ずつ増やしていく。この実施形態により、信号対干渉電力比（ＳＩＲ）の設定値が上限値付近の値を取ることになり、遅延プロファイル生成に必要な処理を最低限の受信特性を満たす範囲で軽減することができる。
【００４２】
なお、同相加算回数を減少させる手段として、前述のように最終スロットから順に１シンボルずつ減らしていく構成のほかに、各スロットでの同相加算回数を１シンボルずつ減らしていく構成とすることができる。即ち、前述の式（１）における、シンボル番号βの上限値５を１つずつ減少させる構成とすることができる。
【００４３】
次に本発明の第５の実施形態について説明する。本発明の第５の実施形態は、各伝送サービスにおける信号対干渉電力比（ＳＩＲ）の設定値に対し、受信信号の実測エラーレート （ＢＥＲ／ＢＬＥＲ）が十分に良好である場合に、遅延プロファイルデータ生成時における同相加算回数を徐々に減らし、処理量を削減する。
【００４４】
予め決められた同相加算回数に対し、現状の受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）が十分に良好であるとき、最終スロット（ｓｌｏｔ ｋ）から順に同相加算の回数を１回ずつ減らしてゆく。最終スロット（ｓｌｏｔ ｋ）の同相加算回数がゼロになった場合は、次に最終スロットの一つ前のスロット（ｓｌｏｔ ｋ−１）から同相加算の回数を１回ずつ減らしてゆく。
【００４５】
そして、同相加算回数を１回減らす度に受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）を確認し、図３に示す上限値を超えていなければ、引き続き同相加算回数を減らしてゆく。エラーレート（ＢＥＲ／ＢＬＥＲ）の上限値を超えた場合は、同相加算回数を減少させる動作を停止し、エラーレート（ＢＥＲ／ＢＬＥＲ）が該上限値以下となるまで、同相加算回数を増やしていく。こうすることにより、エラーレート（ＢＥＲ／ＢＬＥＲ）が上限値付近の値を取ることになり、最低限の受信特性を満たしながら、パスサーチ処理負担が最少となるように軽減することができる。
【００４６】
次に本発明の第６の実施形態について説明する。本発明の第６の実施形態は、遅延プロファイルデータの最大パスの信号対雑音比（Ｓ／Ｎ）を基に、同相加算回数をデフォルト加算回数（初期値）から減少させていき、処理量を軽減する。第３の実施形態と同様に、図４に示すように、遅延プロファイルデータの最大パスに対して或る閾値を設け、パスの信号レベルが該閾値を超えている場合に最終スロット（ｓｌｏｔ ｋ）から順に同相加算を１回ずつ減らしてゆく。
【００４７】
同相加算回数を減少させることにより、パスの信号対雑音比（Ｓ／Ｎ）が低下するため、正確なパス位置を検出することができなくなり、次第に受信特性は劣化する。受信特性の劣化は、最大パスの信号対雑音比（Ｓ／Ｎ）に基づいて判断を行い、最大パスの信号対雑音比（Ｓ／Ｎ）が、予め定めた閾値前後に落ち着くように同相加算回数を調整する。なお、同相加算回数を増加させる過程でデフォルトの加算回数を超えないようにする。
【００４８】
次に本発明の第７の実施形態について説明する。本発明の第７の実施形態は、パイロットシンボルの電力が比較的高い伝送サービスの場合に、電力加算回数又は同相加算回数を減少させていくことで処理量を削減する。図５に、伝送サービスによってシンボルレートが異なる場合のパイロットシンボル及びデータシンボルの電力の関係を示す。
【００４９】
一般に、データシンボルの電力は、１シンボル当たりの所定の電力を確保するために、レートが上がるにつれて高くなる。また、データシンボルと並列して送信されるパイロットシンボルの電力は、データシンボルの電力に対して固定的に一定の比となるように決定されるため、図５に示すように伝送サービスのレートが異なるごとにパイロットシンボルの電力値が変化する。
【００５０】
図５の例は、伝送サービスＡ及び伝送サービスＢ共に、パイロットシンボルとデータシンボルとの電力比が１対１で、伝送サービスＢは伝送サービスＡに対し、データシンボルのレートが２倍である例を示している。伝送サービスＢのデータシンボルの電力は、伝送サービスＡのデータシンボルの電力の２倍となり、パイロットシンボルとデータシンボルとの電力比は１対１であることから、伝送サービスＢのパイロットシンボルの電力は、伝送サービスＡのパイロットシンボルの電力の２倍となる。
【００５１】
パイロットシンボルのレートは一定で、伝送サービスＡと伝送サービスＢとでパイロットシンボルは同一レートであり、伝送サービスＢのようにパイロットシンボルの電力が高い伝送サービスでは信号対雑音比（Ｓ／Ｎ）が十分良く、デフォルト加算回数では加算回数が多過ぎる場合があり得る。
【００５２】
このような伝送サービスに対して、電力加算回数に制限を加えることにより、受信特性をそれほど劣化させることなく、パス検出処理の負荷を軽減させることができる。加算回数は予めシミュレーション等により最適な回数を決定しておき、各伝送サービス毎に加算回数を変化させる。
【００５３】
次に本発明の第８の実施形態について説明する。本発明の第８の実施形態は、遅延プロファイルデータ生成の途中でパス検出を行い、前回のパス検出時と同一のタイミング位置にパスが検出されれば、前回検出されたパスを各フィンガーに割り付け、それ以降の加算処理を省略することにより、パス検出処理の削減を行う。
【００５４】
移動機の移動速度が遅い場合又は停止している場合や、パス検出処理の間隔が短い場合、遅延プロファイルデータに現れるパスのタイミング位置が殆ど変化しない場合がある。このような場合は、前回のパスタイミング位置をそのまま使用すれば良く、それを判別する判断材料として、生成途中の遅延プロファイルデータを用いることとする。
【００５５】
生成途中の遅延プロファイルデータは、式（１）におけるスロット番号αが或る定められたｍ（ｍ＜ｋ）のときのパス検出結果とし、判定に用いるパスは検出されたパスのいずれであってもよい。このような処理を、遅延プロファイルデータの生成ごとに毎回行わずに、間欠的に行うことによっても、トータル的にパス検出処理を削減することができる。
【００５６】
【発明の効果】
以上説明したように、本発明によれば、受信信号のエラーレート（ＢＥＲ／ＢＬＥＲ）、信号対干渉電力比（ＳＩＲ）の設定値又はパスの最大値等に着目し、受信特性が良好である場合に、遅延プロファイルデータ生成における同相加算回数又は電力加算回数を漸次減少させ、受信特性として許容される最低限の限界値付近で加算回数の減少動作を停止し、同相加算回数又は電力加算回数を決定することにより、パスタイミング取得の精度を許容される範囲内に維持しつつ、遅延プロファイルデータ生成に必要な処理を最少限に抑え、処理負担を軽減することができる。
【００５７】
また、パイロットシンボルの受信電力が十分大きい場合に、受信特性に影響を及ぼさない範囲で、同相加算回数又は電力加算回数を減少させることにより、遅延プロファイルデータ生成の処理量を削減し、その削減した分、処理可能なチャネル数を増やしチャネル容量を増加し、又はプロセッサやメモリ等のハードウェアの削減を図ることができる。
【図面の簡単な説明】
【図１】本発明の遅延プロファイルデータ生成機能を有する無線通信機の構成例を示す図である。
【図２】無線データフレーム構成の一例を示す図である。
【図３】受信シンボルの信号対干渉電力比（ＳＩＲ）とエラーレート（ＢＥＲ／ＢＬＥＲ）の特性の関係の一例を示す図である。
【図４】遅延プロファイルデータの一例を示す図である。
【図５】伝送サービスによってレートが異なる場合のパイロットシンボル及びデータシンボルの電力の関係を示す図である。
【符号の説明】
１−１ 受信データ格納メモリ
１−２ マッチドフィルタ（ＭＦ）
１−３ 同相加算部
１−４ 電力変換部
１−５ 電力加算部
１−６ パス検出処理部
１−７ フィンガ部
１−８ 受信データ処理部
１−９ 受信データ判定部
１−１０ 設定ＳＩＲ判定部
１−１１ ハードウェア制御部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wireless communication device having a delay profile data generation function, and more specifically, performs path detection and the like in a code communication multiple access (Code Division Multiple Access) wireless communication device. Wireless communication device having a function of generating delay profile data.
[0002]
[Prior art]
In a CDMA wireless communication device, delay profile data is generated from a received signal, path detection is performed based on the delay profile data, and the received signal is demodulated based on the detected power value and timing position of the RAKE. A technique for performing synthesis to improve the accuracy of demodulated data is generally used.
[0003]
In order to demodulate the CDMA reception signal at the correct timing, it is important to perform processing such as improving the signal-to-noise ratio (S / N) of the path to obtain the path timing as accurate as possible. As a result, the processing load increases, and various devices and improvements have been made to reduce the processing load and reduce the power consumption while maintaining the accuracy of the acquired path timing.
[0004]
Prior art related to the present invention is described in the following Patent Documents 1 to 4. In the technique disclosed in Patent Document 1, the delay profile calculation is stopped based on the reception characteristics, the stop time is made variable, and the average number and / or the number of in-phase additions are changed when the delay profile calculation is performed. Things.
[0005]
Further, the technique disclosed in Patent Document 2 observes a correlation value between delay profiles for each spreading code cycle a plurality of times so that appropriate synchronization detection can be performed even in a communication channel environment in which the reception level fluctuates greatly. If the resulting variance value is smaller than a predetermined value, the delay profile averaging number is determined so that the averaging time is longer. If the variance value is larger than the predetermined value, the delay profile averaging time is shorter. The number of times of averaging is determined, and a delay profile is generated.
[0006]
Further, the one described in Patent Document 3 changes the number of in-phase additions in accordance with the fading frequency (change in the received power value on the time axis), and provides an accurate path without being affected by the fading mode. The present invention relates to a delay profile measurement method that enables detection.
[0007]
Further, the circuit disclosed in Patent Document 4 observes a change in an instantaneous delay profile, and when a predetermined change is not detected, generates an averaged delay profile intermittently and operates an averaging circuit. To reduce power consumption.
[0008]
[Patent Document 1]
JP-A-2001-24557 (paragraphs 0136 to 0138, paragraphs 0148 to 0150, paragraph 0160)
[Patent Document 2]
JP 2001-267958 A (paragraph 0006, paragraphs 0009 to 0019)
[Patent Document 3]
JP 2001-274724 A (paragraphs 0037 to 0055)
[Patent Document 4]
JP-A-2000-278176 (paragraphs 0006 to 0019)
[0009]
[Problems to be solved by the invention]
The present invention provides a wireless communication apparatus having a delay profile data generation function capable of minimizing processing required for delay profile data generation and reducing a processing load while maintaining accuracy of path timing acquisition within an allowable range. It is intended to provide a communication device.
[0010]
[Means for Solving the Problems]
According to the wireless communication device having the delay profile data generation function of the present invention, (1) the signal-to-interference power ratio is higher than the upper limit value of a preset range satisfying the error rate with respect to the target error rate of the received signal. Means for gradually decreasing the number of times of in-phase addition or power addition of delay profile data to be performed to generate highly accurate delay profile data when low, and a reception signal accompanying deterioration of delay profile data due to the decrease of the number of additions. In response to the increase of the error rate, the signal-to-interference power ratio is set to be increased, and when it is detected that the signal-to-interference power ratio has reached the upper limit of the preset range, the delay profile data Means for stopping the operation of gradually decreasing the number of times of addition.
[0011]
(2) In order to generate highly accurate delay profile data when the error rate of the received signal is lower than the target upper limit of a preset range with respect to the set value of the signal-to-interference power ratio. Means for gradually decreasing the number of additions of the in-phase addition or power addition of the delay profile data to be performed, and the error rate of the received signal increases with the deterioration of the delay profile data due to the decrease in the number of additions. And means for stopping the operation of gradually decreasing the number of times of addition of the delay profile data at the point of detecting that the delay profile data has been reached.
[0012]
(3) means for gradually decreasing the number of additions when the signal-to-noise ratio of the maximum path detected by generation of the delay profile data exceeds a preset threshold; Means for stopping the operation of gradually decreasing the number of times of addition of the delay profile data upon detecting that the variance value of the delay profile data exceeds a predetermined threshold value with the deterioration of the delay profile data. is there.
[0013]
(4) means for determining that the transmission service is a transmission service having a high pilot symbol transmission power based on a protocol of an upper layer, and providing a highly accurate delay profile when the transmission service is a transmission service having a high pilot symbol transmission power. Addition to reduce the number of times of in-phase addition or power addition of delay profile data performed for generating data, and to increase the number of times of the in-phase addition or power addition when the transmission service is low in pilot symbol transmission power. And a frequency adjusting means.
[0014]
(5) In the process of performing in-phase addition or power addition of delay profile data to generate highly accurate delay profile data, a path is passed to the same timing position as the path obtained by the previous generation of delay profile data. Means for determining whether or not the delay profile data is detected, and when a path is detected at the same timing position as the path obtained by the previous generation of the delay profile data, in-phase addition or power addition of the delay profile data is performed. Means for stopping the processing.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration example of a wireless communication device having a delay profile data generation function according to the present invention. FIG. 1 shows a reception system of a CDMA wireless communication device, a reception data storage memory 1-1 for temporarily storing reception data, and a matched filter (MF) 1 for calculating and acquiring a correlation between the reception data and a known code. -2, an in-phase addition unit 1-3 that adds in-phase components of the I component and the Q component of the received data after correlation acquisition, and a power conversion unit 1 that converts delay profile data represented by amplitude data into a power value. -4, power addition section 1-5 for adding delay profile data after power conversion, path detection processing section 1-6 for performing path detection processing from power-added delay profile data, detection by path detection processing section 1-6 A finger unit 1-7 for RAKE-combining the received data based on the obtained path information; a reception data processing unit 1-8 for decoding the received data RAKE-combined by the finger unit 1-7; The data is obtained by a reception data determination unit 1-9 and a reception data determination unit 1-9 which determine the characteristics of an error rate (BER / BLER: Bit Error Rate / Block Error Rate) of the reception data processed by the data processing unit 1-8. A setting SIR determining section 1-10 for determining and determining a value to be set as a signal-to-interference power ratio (SIR) of a received signal based on reception characteristics, receiving state information data from each hardware function section, Is transmitted to each hardware function unit.
[0016]
Based on the set value of the signal-to-interference power ratio (SIR) determined by the set SIR determination unit 1-10, closed-loop power control is performed between the communication partner device and the signal-to-interference power ratio (SIR) of the set value. ) Is sent to the communication partner device so that the transmission power is controlled.
[0017]
In order to perform RAKE combining of the received data, the receiving system of the wireless communication device needs to detect the number of paths and path timing of the arriving signal. The effective path is determined based on the delay profile data, and the number and timing are detected. I do. The delay profile data is obtained by demodulating a known symbol sequence (pilot symbol) included in a data frame of a radio signal, adding in-phase addition for adding amplitudes of the in-phase components, and power addition for adding the power value. By doing so, highly accurate delay profile data is generated.
[0018]
Since the noise vector included in the received signal is oriented in a random direction, the longer the in-phase addition period is and the more the number of in-phase additions is, the more the noise vectors cancel each other out, and finally the ratio of the signal components is reduced. Get higher. By converting the sum of the signal component vectors into power values and adding them, delay profile data with small variance is generated.
[0019]
In order to accurately detect a path, it is important to appropriately determine the number of times of in-phase addition and the number of times of power addition, and acquire delay profile data having a good signal-to-noise ratio (S / N) and a small variance. is there. However, since phase rotation and amplitude fluctuation due to fading occur, simply increasing the period of the in-phase addition and the power addition to increase the number of additions may result in reduced accuracy.
[0020]
Therefore, conventionally, the optimum number of times of addition has been determined in advance for each of the in-phase addition and the power addition based on various measurement data and statistical data. In other words, the number of additions is a fixed value regardless of the propagation environment. However, the present invention changes the error rate (BER / BLER) or the set value of the signal-to-noise ratio (S / N) depending on the propagation environment. To change the number of additions so that the number of additions is the minimum required.
[0021]
FIG. 2 shows an example of a wireless data frame configuration. Here, an area where the in-phase addition (amplitude addition) is performed is defined as a slot. In addition, averaging is performed by applying power addition to addition between slots. In the wireless data frame shown in FIG. 2, one slot is composed of 5 symbols, the upper limit of the number of in-phase additions is 5 for each slot, the upper limit of the number of power additions between slots is k, and the final power addition value. Is represented by the following equation (1).
[0022]
(Equation 1)

Here, α indicates a slot number, and β indicates a symbol number.
[0023]
It is in-phase addition between pilot symbols that increases the signal-to-noise ratio (S / N) of the path, and power addition has the effect of reducing variance. The reason for increasing the signal-to-noise ratio (S / N) of the path is to improve the reception characteristics (BER / BLER) by performing demodulation based on the accurate path timing. If the conditions are satisfied and the reception characteristics have a margin, even if the accuracy of path detection is slightly lowered, the reception result is not affected. Therefore, it is possible to reduce the processing used for path detection within a range that does not affect the reception result, to transfer the reduced processing to other processing, or to reduce power consumption.
[0024]
FIG. 3 shows an example of the relationship between the signal-to-interference power ratio (SIR) of received symbols and the characteristics of the error rate (BER / BLER). An embodiment of the present invention will be described based on the relationship between the characteristics. The first embodiment of the present invention relates to a case where a set value of a signal-to-interference power ratio (SIR) is sufficiently low with respect to a target error rate (BER / BLER) in each transmission service and reception characteristics are good. In addition, the number of power additions in delay profile data generation is gradually reduced, and the amount of power addition processing is reduced.
[0025]
For a certain target error rate (BER / BLER), the range of the signal-to-interference power ratio (SIR) in which the target error rate (BER / BLER) can be obtained is measured in advance and determined and set. In FIG. 3, the range of the signal-to-interference power ratio (SIR) is represented as a range from “SIR lower limit” to “SIR upper limit”.
[0026]
If the actual set value of the signal-to-interference power ratio (SIR) of the wireless communication device is within the range from the “SIR lower limit” to the “SIR upper limit”, the number of power additions in the next generation of delay profile data is set to one. cut back. That is, the number of power additions in Equation (1) is k-1.
[0027]
After that, the set value of the signal-to-interference power ratio (SIR) is checked every time the delay profile data is generated, and the same processing is repeated. As the number of power additions decreases, the variance of delay profile data increases, so that the accuracy of path detection decreases, and as a result, reception characteristics (BER / BLER) deteriorate.
[0028]
Then, the set value of the signal-to-interference power ratio (SIR) is increased, and a power control command requesting the communication partner device to increase the transmission power is transmitted. By repeating this, the set value of the signal-to-interference power ratio (SIR) gradually increases, and exceeds the upper limit of the predetermined signal-to-interference power ratio (SIR) set value shown in FIG.
[0029]
Then, when the predetermined upper limit of the signal-to-interference power ratio (SIR) set value is exceeded, the operation of reducing the number of power additions is stopped, and thereafter, the set value of the signal-to-interference power ratio (SIR) is reduced. The number of additions is increased or decreased so as to settle near the upper limit. In addition, when increasing the number of times of power addition, the number of times of addition should not exceed the default upper limit number k. By doing so, it is possible to reduce the addition processing required for generating the delay profile within a range that satisfies the minimum reception characteristics.
[0030]
Next, a second embodiment of the present invention will be described. In the second embodiment of the present invention, when the measured error rate (BER / BLER) of the received signal is sufficiently good for the set value of the signal-to-interference power ratio (SIR) in each transmission service, the delay profile data The number of power additions in the generation is gradually reduced to reduce the processing amount.
[0031]
As shown in FIG. 3, the upper limit and the lower limit of the error rate (BER / BLER) of the received signal are previously measured and determined for the set value of the signal-to-interference power ratio (SIR). If the measured error rate (BER / BLER) of the received signal is lower than the upper limit, the number of power additions is reduced by one, and the received data is determined by the received data determination unit 1-9 until the next delay profile is generated. The data error rate (BER / BLER) is determined.
[0032]
As the number of power additions decreases, the variance increases, with the result that the path detection accuracy decreases and the error rate (BER / BLER) increases. The error rate (BER / BLER) of the received signal is monitored while reducing the number of power additions by one from the default number (initial value), and the operation of reducing the number of power additions when the error rate exceeds the upper limit is stopped. I do.
[0033]
Then, the number of times of power addition is increased until the error rate (BER / BLER) of the received signal becomes lower than the upper limit. In other words, by changing the value of the number of times of power addition k in the equation (1), the error rate (BER / BLER) of the received signal always becomes a value near the upper limit, and the path search processing is performed while satisfying the minimum receiving characteristic. The burden can be reduced to a minimum.
[0034]
Next, a third embodiment of the present invention will be described. In the third embodiment of the present invention, the number of power additions is gradually reduced from the number of default additions (initial value) based on the signal-to-noise ratio (S / N) of the maximum path of the delay profile data, thereby reducing the processing amount. . As shown in FIG. 4, a certain threshold value is provided for the maximum path of the delay profile data, and when the signal level of the path exceeds the threshold value, the number of power additions is reduced by one. That is, the value of the number of power additions k in Expression (1) is decreased by one.
[0035]
By reducing the number of power additions, the variance of delay profile data increases, so that multipath cannot be accurately captured, and the error rate (BER / BLER) of the received signal gradually increases. The deterioration of the reception characteristics is determined based on a threshold value for the variance (σ in FIG. 4) of the delay profile data.
[0036]
The number of power additions is reduced as long as the variance of the delay profile data does not exceed the threshold. When calculating the variance, in order to suppress the influence of the peak value of the path as much as possible, all the paths exceeding the threshold value are added with the threshold value as the power value of the path.
[0037]
In this embodiment, the number of power additions can be adjusted without having to acquire the error rate (BER / BLER) of the received signal, so that the propagation state can be promptly reflected in the processing. In addition, in the process of increasing the number of times of power addition, the number of times of power addition does not exceed the default upper limit number k.
[0038]
Next, a fourth embodiment of the present invention will be described. The fourth embodiment of the present invention is based on the case where the set value of the signal-to-interference power ratio (SIR) is sufficiently low with respect to the target error rate (BER / BLER) in each transmission service and the reception characteristics are good. The number of in-phase additions in delay profile data generation is gradually reduced to reduce the amount of processing.
[0039]
When the set value of the signal-to-interference power ratio (SIR) is sufficiently low with respect to a certain target error rate (BER / BLER), the number of times of the in-phase addition is increased by one in order from the last slot (slot k) of the wireless data frame. I will reduce it. When the number of times of in-phase addition of the last slot (slot k) becomes zero, the number of times of in-phase addition is reduced one by one from the slot (slot k-1) immediately before the last slot.
[0040]
By reducing the number of in-phase additions, the signal-to-noise ratio (S / N) of the path decreases, and the reception characteristics gradually deteriorate. As a result, the set value of the signal-to-interference power ratio (SIR) is increased, and a power control command requesting the communication partner device to increase the transmission power is transmitted.
[0041]
When the set value of the signal-to-interference power ratio (SIR) exceeds the upper limit, the reduction of the number of times of in-phase addition is stopped, and the in-phase addition is performed until the set value of the signal-to-interference power ratio (SIR) becomes lower than the upper limit. Increase the number of times by one. According to this embodiment, the set value of the signal-to-interference power ratio (SIR) takes a value near the upper limit, and the processing required for delay profile generation can be reduced to the extent that the minimum reception characteristics are satisfied. .
[0042]
As means for reducing the number of in-phase additions, a configuration in which the number of in-phase additions in each slot is reduced by one symbol in addition to the configuration in which one symbol is sequentially reduced from the last slot as described above. . That is, it is possible to adopt a configuration in which the upper limit value 5 of the symbol number β in the above-described equation (1) is decreased by one.
[0043]
Next, a fifth embodiment of the present invention will be described. The fifth embodiment of the present invention provides a delay profile when a measured error rate (BER / BLER) of a received signal is sufficiently good for a set value of a signal-to-interference power ratio (SIR) in each transmission service. The number of in-phase additions at the time of data generation is gradually reduced to reduce the amount of processing.
[0044]
When the error rate (BER / BLER) of the current reception signal is sufficiently good for a predetermined number of in-phase additions, the number of in-phase additions is reduced by one in order from the last slot (slot k). When the number of times of in-phase addition of the last slot (slot k) becomes zero, the number of times of in-phase addition is reduced one by one from the slot (slot k-1) immediately before the last slot.
[0045]
Then, each time the number of in-phase additions is reduced by one, the error rate (BER / BLER) of the received signal is checked. If the error rate does not exceed the upper limit shown in FIG. 3, the number of in-phase additions is continuously reduced. When the error rate (BER / BLER) exceeds the upper limit, the operation of reducing the number of common-mode additions is stopped, and the number of common-mode additions is increased until the error rate (BER / BLER) becomes equal to or less than the upper limit. . By doing so, the error rate (BER / BLER) takes a value near the upper limit, and it is possible to reduce the path search processing load to a minimum while satisfying the minimum reception characteristics.
[0046]
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment of the present invention, the number of in-phase additions is reduced from the default number of additions (initial value) based on the signal-to-noise ratio (S / N) of the maximum path of the delay profile data, and the processing amount is reduced. To reduce. As in the third embodiment, as shown in FIG. 4, a certain threshold is set for the maximum path of the delay profile data, and when the signal level of the path exceeds the threshold, the last slot (slot k) is set. The in-phase addition is reduced one by one in order from.
[0047]
By reducing the number of in-phase additions, the signal-to-noise ratio (S / N) of the path decreases, so that an accurate path position cannot be detected and the reception characteristics gradually deteriorate. The deterioration of the reception characteristic is determined based on the signal-to-noise ratio (S / N) of the maximum path, and the in-phase addition is performed so that the signal-to-noise ratio (S / N) of the maximum path is settled around a predetermined threshold value. Adjust the number of times. In the process of increasing the number of in-phase additions, the default addition number is not exceeded.
[0048]
Next, a seventh embodiment of the present invention will be described. The seventh embodiment of the present invention reduces the amount of processing by reducing the number of power additions or the number of in-phase additions for a transmission service in which the power of pilot symbols is relatively high. FIG. 5 shows the power relationship between pilot symbols and data symbols when the symbol rate differs depending on the transmission service.
[0049]
In general, the power of a data symbol increases as the rate increases in order to secure a predetermined power per symbol. Further, since the power of the pilot symbol transmitted in parallel with the data symbol is determined so as to have a fixed fixed ratio with respect to the power of the data symbol, as shown in FIG. The power value of the pilot symbol changes every time it differs.
[0050]
In the example of FIG. 5, the transmission service A and the transmission service B have a power ratio of pilot symbols to data symbols of 1 to 1, and the transmission service B has a data symbol rate twice that of the transmission service A. Is shown. The power of the data symbol of the transmission service B is twice the power of the data symbol of the transmission service A, and the power ratio of the pilot symbol to the data symbol is 1: 1. , Twice the power of the pilot symbol of transmission service A.
[0051]
The pilot symbol rate is constant, the pilot symbols are the same in transmission service A and transmission service B, and the signal-to-noise ratio (S / N) is high in transmission services with high pilot symbol power such as transmission service B. It is good enough that the default number of additions may be too large.
[0052]
By limiting the number of power additions for such a transmission service, it is possible to reduce the load of the path detection processing without significantly deteriorating the reception characteristics. The optimum number of additions is determined in advance by simulation or the like, and the number of additions is changed for each transmission service.
[0053]
Next, an eighth embodiment of the present invention will be described. According to the eighth embodiment of the present invention, a path is detected in the middle of delay profile data generation, and if a path is detected at the same timing position as the time of the previous path detection, the previously detected path is assigned to each finger. By omitting the subsequent addition processing, the path detection processing is reduced.
[0054]
When the moving speed of the mobile device is slow or stopped, or when the interval of the path detection processing is short, the timing position of the path appearing in the delay profile data may hardly change. In such a case, the previous path timing position may be used as it is, and the delay profile data being generated is used as a criterion for determining the position.
[0055]
The delay profile data being generated is a path detection result when the slot number α in Equation (1) is a predetermined m (m <k), and the path used for determination is any of the detected paths. Is also good. By performing such processing intermittently instead of every time the delay profile data is generated, the path detection processing can be totally reduced.
[0056]
【The invention's effect】
As described above, according to the present invention, the reception characteristic is good by focusing on the error signal (BER / BLER) of the received signal, the set value of the signal-to-interference power ratio (SIR), the maximum value of the path, and the like. In this case, the number of times of in-phase addition or the number of times of power addition in delay profile data generation is gradually reduced, and the operation of decreasing the number of times of addition is stopped near the minimum limit value allowed as reception characteristics, and the number of times of in-phase addition or power addition is reduced. With this determination, the processing required for delay profile data generation can be minimized and the processing load can be reduced while maintaining the accuracy of path timing acquisition within an allowable range.
[0057]
Further, when the received power of the pilot symbol is sufficiently large, the processing amount of delay profile data generation is reduced by reducing the number of times of in-phase addition or the number of power additions within a range that does not affect reception characteristics, thereby reducing the amount of processing. Accordingly, the number of channels that can be processed can be increased, the channel capacity can be increased, or hardware such as a processor and a memory can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a wireless communication device having a delay profile data generation function according to the present invention.
FIG. 2 is a diagram illustrating an example of a wireless data frame configuration.
FIG. 3 is a diagram illustrating an example of a relationship between characteristics of a received symbol signal-to-interference power ratio (SIR) and an error rate (BER / BLER).
FIG. 4 is a diagram illustrating an example of delay profile data.
FIG. 5 is a diagram illustrating the relationship between the power of pilot symbols and the power of data symbols when the rate differs depending on the transmission service.
[Explanation of symbols]
1-1 Received data storage memory 1-2 Matched filter (MF)
1-3 In-phase addition section 1-4 Power conversion section 1-5 Power addition section 1-6 Path detection processing section 1-7 Finger section 1-8 Received data processing section 1-9 Received data determination section 1-10 Setting SIR determination Unit 1-11 Hardware control unit

Claims (5)

For the target received signal error rate, if the signal-to-interference power ratio is lower than the upper limit of a predetermined range that satisfies the error rate,
Means for gradually decreasing the number of times of in-phase addition or power addition of delay profile data to be performed to generate highly accurate delay profile data,
A setting is made to increase the signal-to-interference power ratio in response to an increase in the error rate of the received signal due to the deterioration of the delay profile data due to the decrease in the number of additions, and the signal-to-interference power ratio is set to the upper limit of the preset range. Means for halting the operation of gradually decreasing the number of times of addition of the delay profile data upon detecting that the value has reached the value, the wireless communication device having a delay profile data generation function. For the set value of the signal-to-interference power ratio, when the error rate of the received signal is lower than the upper limit of the target preset range,
Means for gradually decreasing the number of times of in-phase addition or power addition of delay profile data to be performed to generate highly accurate delay profile data,
With the deterioration of the delay profile data due to the decrease in the number of additions, the number of additions of the delay profile data is gradually reduced when the error rate of the received signal reaches the upper limit of the preset range. And a means for stopping the operation of causing the wireless communication device to have a delay profile data generation function. Means for gradually decreasing the number of additions, when the signal-to-noise ratio of the maximum path detected by the generation of the delay profile data exceeds a preset threshold,
Means for stopping the operation of gradually decreasing the number of additions of the delay profile data upon detecting that the variance value of the delay profile data exceeds a predetermined threshold with the deterioration of the delay profile data due to the decrease in the number of additions. A wireless communication device having a delay profile data generation function. Means for determining that the transmission service is high in transmission power of pilot symbols based on an upper layer protocol;
In the case of a transmission service in which the transmission power of pilot symbols is high, the number of times of in-phase addition or power addition of delay profile data performed to generate highly accurate delay profile data is reduced, and transmission of pilot symbol transmission power is low. A wireless communication device having a delay profile data generation function, comprising: an addition number adjusting means for increasing the number of additions of the in-phase addition or the power addition when the service is a service. In the process of performing in-phase addition or power addition of delay profile data and generating highly accurate delay profile data,
Means for determining whether a path is detected at the same timing position as the path obtained by generating the previous delay profile data,
Means for stopping the in-phase addition or power addition processing of the delay profile data when a path is detected at the same timing position as the path obtained by the previous generation of the delay profile data. Wireless communication device having a function of generating delay profile data.

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