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Home | Seminars and Symposia | Past seminars/symposia: Monday, April 30, 2007

Performance Analysis of VoIP Over Wireless Broadband


Phil Fleming
Motorola Corp.
(Joint work with Burt Simon, University of Colorado, Denver)

Monday, April 30, 2007
4:00 pm

402 Walter Library

We present results on the buffer dynamics for a wireless broadband communication link serving a large number of periodic realtime traffic sources (e.g. the output of a low bit rate voice codec.) We model the aggregate traffic as a fluid whose rate at any given time, measured in modulation symbols per second, is determined by the state of an multivariate Ornstein-Uhlenbeck process. This model captures three important aspects of the input traffic: the on-off nature of one leg of a phone conversation, the variable bit rate of the communication channel introduced by adaptive coding and modulation and the variable number of active calls. The communication link can then be simply modeled as a constant rate fluid server. This allows us to apply known methods developed over the last 20 years to analyze the internet. In particular, we analyze the buffer dynamics using methods developed to handle queues with Gaussian input.