Esra Cansu KÖSE, Abdulkadir YAYILKAN, Selman KULAC, Hakkı İLK

Büyük Ölçekli Mimo Sistemlerde Pilot Kirliliğini Azaltmaya Yönelik Çağdaş Yaklaşımlar

Büyük Çoklu Giriş Çoklu Çıkış (MIMO), gelecekte mobil ağlar için yüksek veri kapasitesi talebini karşılamak için umut verici bir teknolojidir. MIMO sistemlerinde kanal durum bilgisinin (CSI) elde edilmesi, enerji ve spektrum verimliliği sağlar. Bu nedenle, CSI'nin doğruluğu çok önemlidir. Zaman Bölmeli Çift Yönlendirme (TDD), Massive MIMO sistemlerinde CSI elde etmek için iyi bir alternatif yöntemdir. CSI elde etmek için pilot diziler kullanılır. Pratikte, her kullanıcı terminaline farklı bir pilot dizisi atamak mümkün değildir. Özellikle Massive MIMO sistemlerinde farklı hücrelerde aynı pilot dizilerin kullanılması pilot kontaminasyonu sorununa neden olmaktadır. Bu sorunu azaltmak için birçok çalışma yapılmıştır. Bu çalışmada, pilot kontaminasyonunun nedenleri tartışılmakta ve pilot kontaminasyonunu ortadan kaldırmak veya azaltmak için literatürde önerilen yöntemler sunulmaktadır. Ayrıca, Massive MIMO'da pilot kontaminasyonla ilgili güvenlik durumu ve gelecekteki sistemlerde önemli olabilecek diğer ilgili konular vurgulanmıştır.

Anahtar Kelimeler:

Pilot Contamination (PC) Mitigation, Massive MIMO Systems, Channel State Information (CSI), Time Division Duplex (TDD), Frequency Division Duplex (FDD).

Contemporary Approaches to Mitigate Pilot Contamination in Massive Mimo Systems

Massive Multiple Input Multiple Output (MIMO) is a promising technology for meeting the demand of high data capacity for mobile networks in the future. Obtaining channel state information (CSI) in MIMO systems provides energy and spectrum efficiency. Hence, the accuracy of the CSI is very important. Time Division Duplexing (TDD) is a good alternative method to obtain CSI in Massive MIMO systems. Pilot sequences are used to obtain CSI. In practice, it is not possible to assign a different pilot sequence to each user terminal. In particular, the use of the same pilot sequences in different cells in Massive MIMO systems causes the problem of pilot contamination. Many studies have been conducted in an attempt to mitigate this problem. In this study, the reasons for pilot contamination are discussed and the methods proposed in the literature for eliminating or mitigating pilot contamination are presented. In addition, the case of pilot contamination-related security in Massive MIMO and other related issues that may be important in future systems are highlighted.

Keywords:

Pilot Contamination (PC) Mitigation, Massive MIMO Systems, Channel State Information (CSI), Time Division Duplex (TDD), Frequency Division Duplex (FDD).,

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