Evaluation of Scheduling Algorithms under Mobility in a Realistic Ray-Traced Wireless Network

Year 2025, Volume: 1 Issue: 2, 16 - 28, 29.09.2025

Önem Yıldız

Abstract

Efficient scheduling and link adaptation mechanisms are essential for ensuring reliable and high-throughput communication in mobile wireless networks, particularly in the context of future 6G systems. This study investigates the performance of three prominent scheduling algorithms—Round Robin (RR), Best Channel Quality Indicator (Best-CQI), and Proportional Fair (PF)—in a realistic ray-traced wireless environment under user mobility. A time-evolving scenario is designed where mobile users follow predefined trajectories, and the downlink transmission is evaluated in terms of effective Signal-to-Interference-plus-Noise Ratio (SINR), spectral efficiency, and achieved Transport Block Error Rate (TBLER). Link adaptation is implemented via an Outer Loop Link Adaptation (OLLA) mechanism that dynamically adjusts the modulation and coding scheme based on feedback. The results show that PF scheduling achieves a balanced trade-off between throughput and fairness, maintaining spectral efficiency close to the Shannon capacity while satisfying the target BLER for all users. In contrast, Best-CQI provides high spectral efficiency for strong users but degrades the performance of users with weaker channel conditions. RR ensures fairness but suffers from throughput inefficiencies under dynamic SINR variations. The study highlights the importance of scheduler selection in mobility-aware systems and demonstrates how OLLA-driven adaptation improves robustness in realistic, time-varying channels.

Keywords

6G , Link Adaptation , Ray Tracing Simulation , Scheduling , User Mobility

Gerçekçi Işın İzlemeli Kablosuz Ağda Hareketlilik Altında Çizelgeleme Algoritmalarının Değerlendirilmesi

Abstract

Verimli planlama ve bağlantı uyarlama mekanizmaları, özellikle gelecekteki 6G sistemleri bağlamında, mobil kablosuz ağlarda güvenilir ve yüksek verimli iletişimi sağlamak için esastır. Bu çalışma, kullanıcı hareketliliği altında gerçekçi ışın izlemeli kablosuz ortamda üç önemli planlama algoritmasının performansını incelemektedir: Round Robin (RR), Best Channel Quality Indicator (Best-CQI) ve Proportional Fair (PF). Mobil kullanıcıların önceden tanımlanmış yörüngeleri takip ettiği ve aşağı bağlantı iletiminin etkili Sinyal-Girişim-Artı-Gürültü Oranı (SINR), spektral verimlilik ve elde edilen Taşıma Bloğu Hata Oranı (TBLER) açısından değerlendirildiği zamanla değişen bir senaryo tasarlanmıştır. Bağlantı uyarlaması, geri bildirime dayalı olarak modülasyon ve kodlama şemasını dinamik olarak ayarlayan bir Dış Döngü Bağlantı Uyarlaması (OLLA) mekanizması aracılığıyla uygulanmaktadır. Sonuçlar, PF planlamasının, tüm kullanıcılar için hedef BLER'yi karşılayarak Shannon kapasitesine yakın spektral verimliliği koruyarak verimlilik ve adalet arasında dengeli bir denge sağladığını göstermektedir. Buna karşılık, Best-CQI güçlü kullanıcılar için yüksek spektral verimlilik sağlamakta ancak daha zayıf kanal koşullarına sahip kullanıcıların performansını düşürmektedir. RR ise adaleti sağlar ancak dinamik SINR değişimleri altında verim yetersizliklerinden muzdariptir. Çalışma, hareketlilik farkındalığı olan sistemlerde zamanlayıcı seçiminin önemini vurgulamakta ve OLLA odaklı adaptasyonun gerçekçi, zamanla değişen kanallarda sağlamlığı nasıl iyileştirdiğini göstermektedir.

Keywords

6G , Bağlantı Adaptasyonu , Işın İzlemeli Simülasyon , Çizelgeleme , Kullanıcı Hareketliliği

Ethical Statement

Bu araştırmada hayvanlar ve insanlar üzerinde herhangi bir çalışma yapılmadığı için etik kurul onayı alınmamıştır.

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