Application of Cyclic Delay Transmit Diversity to DS-CDMA using Frequency-domain Equalization
نویسندگان
چکیده
あらまし 周波数領域等化を用いる DS-CDMA において,複数のアンテナに異なる遅延を与えて同一信号を同時に送 信し,等価的にパス数を増やすことで大きな,周波数ダイバーシチ効果を得ることのできる遅延送信ダイバーシチ(DTD)が 提案されている.しかし DTD では,各アンテナに与える遅延時間が大きくなると,最大パス遅延がガードインターバル(GI)よ り長くなり符号間干渉を生じるため,平均 BER 特性が劣化してしまう.最近,アンテナごとに異なる循環遅延を与えて同時に 送信する Cyclic Delay Transmit Diversity (CDTD)が提案されている.CDTDでは,DTD と異なり各アンテナに与える循環遅 延の量に制限がないために,DTD より大きな周波数ダイバーシチ効果を得ることができる.本論文では,周波数領域等化を 用いる DS-CDMAに CDTD を適用したときの平均 BER特性を計算機シミュレーションによって明らかにし, DTD を用いる ときの BER特性と比較している. キーワード DS-CDMA,遅延送信ダイバーシチ (DTD),Cyclic Delay Transmit Diversity (CDTD),周波数領域等化
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تاریخ انتشار 2005