Measurement Aided Model Design for WCDMA Link Error Statistics

Accurate models for error characteristics of radio channels are essential to estimate performance of data transmission. This paper analyzes error-gap and error-burst statistics of the WCDMA dedicated channel (DCH) and provides respective models. We start with an analytical study of the outer-loop power control mechanism (OLPC), which gives directions to this work, revealing that the OLPC strongly influence error behavior. We prove this by large-scale measurements at the Iub-interface of a live UMTS network. Beside statistical evaluation of the measurement data we provide a simple generative hidden Markov model for emulation of DCH errors. It is able to characterize any arbitrary DCH by only two parameters, with an accuracy below 1%, in terms of Kullback-Leibler divergence. This novel model presents an accurate light-weight alternative to complex tools for simulation of WCDMA DCH connections. It also covers all other communication technologies deploying a similar power control mechanism.