Evolution of land mobile radio (including personal) communications

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TmpReE1RPT0.pdf

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1996

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Sözer, Mutlu Ethem
Tanık, Yalçın
Ünal, Berna Sayraç

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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Bu raporda COST 231 projesinin genelinde ele alınan konular ve varılan sonuçlar özetlenmekte ve ODTÜ araştırma grubunda yürütülmüş çalışmalar tanıtılmaktadır. Çalışmalar temel olarak 3. nesil hücresel-mobil iletişim sistemlerde kapasite artışım hedeflemiştir. Buna bir çözüm olarak hem bina dışı hem de bina içi uygulamalarda kod bölmeli çoklu erişim (CDMA) sistemleri incelenmiştir. Bina dışı CDMA sisteminde BPSK yöntemi kullanan , doğrudan dizili yaygın spektrum (DSSS) yöntemi ele alınmıştır. Kanal sümülasyonlarında Suzuki-Hashemi modeli kullanılmıştır. Alıcı, kanal kestirimi yapan bir RAKE yapıya dayalıdır. Elde edilen sonuçlar, mobil sistemlerde kanal kestiriminin oldukça basit yöntemler kullanılarak yapılmasının önemli bir kayba neden olmadığını göstermiştir. İdeal güç kontrolü kullanımı sağlansa bile kanal örüntüsüne bağlı olarak bit hata oranının bire on gibi büyük oranlarda değişebileceği gösterilmiştir. Baz istasyondan mobillere olan iletimde, ses iletişimine uygun bir kriter kullanılarak, literatürde yer alan güç kontrolü algoritmalarının parametreleri optimize edilmiş ve önemli iyileşmeler elde edilmiştir. Ayrıca, bina içi hücresel sistemlerde kullanıma uygun olan senkron CDMA (SCDMA) sistemlerinde ortaya çıkan girişim problemleri incelenmiş ve girişimi azaltan yeni bir yöntem geliştirilmiştir. Bu yöntemde yayma dizisi sürekli olarak değiştirilerek girişim nedeniyle yetersiz kalan iletim iyileştirilmekte ve iki kata varan kapasite artışı sağlanabilmektedir.

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https://app.trdizin.gov.tr/publication/project/detail/TmpReE1RPT0
https://hdl.handle.net/11511/50292

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Department of Electrical and Electronics Engineering, Project and Design

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Citation Formats

M. E. Sözer, Y. Tanık, and B. S. Ünal, “Evolution of land mobile radio (including personal) communications,” 1996. Accessed: 00, 2020. [Online]. Available: https://app.trdizin.gov.tr/publication/project/detail/TmpReE1RPT0.