Comparison between Scheduling Techniques in Long Term Evolution

Abstract

Long-Term Evolution (LTE) is a recently evolving technology characterized by very high speed data rate that allows users to access internet through their mobile as well as through other electronic devices.  Such technology is intended to support variety of IP-based heterogeneous traffic types. Traffic scheduling plays an important role in LTE technology by assigning the shared resources among users in the most efficient manner. This paper discusses the performance of three types of scheduling algorithms namely: Round Robin, best Channel Quality Indicator (CQI) and Proportional Fair (PF) schedulers representing the extreme cases in scheduling. The scheduling algorithms performances on the downlink were measured in terms of throughput and block error rate using a MATLAB-based system level simulation. Results indicate that the best CQI algorithm outperforms other algorithms in terms of throughput levels but on the expense of fairness to other users suffering from bad channel conditions.

ABSTRAK: Teknologi baru Evolusi Jangka Panjang (LTE) sentiasa berubah dan ia bercirikan kelajuan kadar data sangat tinggi yang membolehkan pengguna mengakses internet melalui telefon bimbit dan peranti elektronik lain. Teknologi seperti ini bertujuan menyokong pelbagai jenis trafik heterogen berasaskan IP. Penjadualan trafik memainkan peranan penting dalam teknologi LTE bagi mengagihkan sumber perkongsian secara paling berkesan di kalangan pengguna. Kertas ini membincangkan prestasi tiga jenis algoritma penjadualan iaitu: pusingan Robin, penunjuk kualiti saluran (CQI) terbaik dan  penjadualan berkadar adil (PF) yang merupakan kes ekstrem dalam penjadualan. Prestasi penjadualan Algoritma di pautan turun diukur dari segi daya pemprosesan dan kadar ralat blok melalui simulasi  sistem menggunakan MATLAB. Hasil kajian menunjukkan algoritma CQI adalah yang terbaik berbanding hasil algoritma lain dari segi tahap daya pemprosesan tetapi algoritma ini menyebabkan pengguna lain mengalami keadaan saluran buruk.

KEYWORDS: LTE; round robin; best CQI; proportional fair; scheduling; resource blocks