Comparison of Packet Scheduling Algorithms Focusing on User Throughput in High Speed Downlink Packet Access

Yoshiaki OFUJI
Sadayuki ABETA

IEICE TRANSACTIONS on Communications   Vol.E86-B    No.1    pp.132-141
Publication Date: 2003/01/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Multiple Access and Signal Transmission Techniques for Future Mobile Communications)
packet scheduling,  HSDPA,  user throughput,  coverage,  

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This paper compares by computer simulation the achievable throughput performance employing fast packet scheduling algorithms focusing on the throughput of each user in High Speed Downlink Packet Access (HSDPA). Three packet scheduling algorithms are employed: the Maximum carrier-to-interference power ratio (CIR), Proportional Fairness (PF), and Round Robin (RR) methods. The simulation results elucidate that although the Maximum CIR method achieves an aggregated user throughput within a cell higher than that using the PF and RR methods, the PF method is advantageous because it enhances the user throughput for a large number of users with a lower received signal-to-interference power ratio (SIR), who are located outside the normalized distance of 0.6-0.7 from a cell site (this corresponds to the area probability of 50-60% within the cell) compared to the Maximum CIR method. It is also shown that when the PF method is employed, the probability of user throughput of greater than 2 Mbps in the vicinity of the cell site becomes approximately 45% (5%) for L = 1-path (2-path) fading channel, while it is almost 80% (50%) when using the Maximum CIR method. Finally, we show that the average user throughput in a 2-path Rayleigh fading channel is reduced by approximately 30% compared to that in a 1-path channel due to severe multipath interference (MPI) and that the average user throughput is strongly affected by the total traffic produced within a cell, which is directly dependent on the number of users within a cell and the data size per packet call.