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1	Interception Techniques For Direct Sequence Spread Spectrum Signals Karadeniz, Uygar 01 December 2005 (has links) (PDF) In this work interception and spreading sequence estimation of Direct Sequence Spread Spectrum (DSSS) signals, in low signal to noise power ratios is discussed. For interception an approach based on autocorrelation fluctuations is employed and also symbol period is estimated from this interception process. Spreading sequence estimation is performed by using eigenanalysis of the correlation matrix and estimated symbol period. These approaches are applied on different kinds of DSSS signals including 3rd generation UMTS signal and LPI radar signals. In order to examine the channel effects such as / multipath, interference and colored noise, on the performance of applied techniques, detailed analysis results are obtained. The results are compared with the performances of alternative interception techniques. DSSS, interception, Spreading Sequence
2	Multi-rate coding schemes for gaussian multiple access channel / ガウス型多重接続通信路のためのマルチレート符号化法 / ガウスガタタジュウセツゾクツウシンロノタメノマルチレートフゴウカホウ何美霖, Meilin He 22 March 2018 (has links) 本研究で提案するマルチレート符号化法は、各ユーザが同じ通信路符号器を持つものの、符号器のパラメータ(Repeat Accumulate符号の繰り返し回数)と符号器に直列に連接する拡散列の長さを変化させることで、異なるレートの情報伝送を実現する、という方法である。通信路にガウス雑音が加算される場合、任意に低い誤り率の高信頼通信を可能にし、合計伝送レートを最大にする最適な通信路符号のパラメータと拡散長を理論解析で求める。 / In this dissertation, the same encoder is employed for each user, and different rate transmissions is realized by adjusting the parameter of the encoder. We analyze the decoding performances of our coding schemes, and obtain the optimal coding parameters, which gives the maximum sum rates and approach the theoretical limits of the channel. The proposed coding schemes support multimedia services, and avoid employing multiple channel encoders to implement the multi-rate transmission. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University マルチレート RA符号拡散列 multi-rate RA code Spreading sequence
3	周波数偏差を伴うスペクトル拡散信号における高速同期捕捉に関する研究片山, 正昭 January 1997 (has links) 科学研究費補助金研究種目:基盤研究(C)(2) 課題番号:07805037 研究代表者:片山正昭研究期間:1995-1996年度低軌道衛星通信システム搬送波周波数偏差 FFT 分割マッチドフィルタ搬送波周波数捕捉スペクトル拡散通信方式信号処理拡散符号捕捉 Signal Processing Low Earth-Orbital Satellite System Spread Spectrum Sommunication Acquisition of a Spreading Sequence 高速同期捕捉 Divided Matched Filter Estimation of the Carrier Frequency M値スペクトル拡散通信方式スペクトル拡散通信システム Carrier Frequency Offset

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