Delay in UMTS Radio Access Networks: Analytical Study and Validation

This paper deals with the delay analysis of the traffic within the UMTS Terrestrial Radio Access Network (UTRAN). Delay is a very important Quality of Service aspect in the UTRAN. Especially, the delay over the Iub link is the major limited factor for the dimensioning of the UTRAN. Based on the system analysis, a queuing model is proposed in this paper to derive the delay time over the Iub interface. The arrival process is based on Batch Markovian Arrival Process (BMAP). The suggested queuing model and the related notable results are validated by comparing with simulations. Additionally, we propose a superposition technique applying on the BMAP model to scale the source traffic. Then in this way, not only the delay performance on the Iub interface can be calculated analytically with the proposed queuing model, but also with the suggested superposition technique, the traffic can be scaled to different load ranges based on a basic load, and furthermore the delay times for all various ranges of traffic loads can be also derived with the proposed queuing model. Keywords-UTRAN, Iub, FP PDU delay, BMAP, BMAP/D/1