Minimising Distortion via Multiuser Resource Allocation Michael Mecking and Thomas Stockhammer Institute for Communications Engineering (LNT) Munich University of Technology (TUM) D-80290 Munich, Germany phone: +49 89 28923474, e–mail: Michael.Mecking, Thomas.Stockhammer @EI.TUM.de November 16, 2001 Abstract We investigate source–controlled resource allocation for orthogonal transmission of heterogenous sources over a multiuser system. The system resources bandwidth and power are shared among all users in such a way that the average distortion for all users is minimised. Especially in mobile communications, the allocation of resources among users with different applications is a challenging task. To illuminate this com- plex problem we consider simple models for source, channel, and distortion measure. For a constant channel rate the resource allocation reduces to a statistical multiplex- ing problem. In this case, only the source characteristics are exploited to optimally assign rate to each user. Additionally, if the channel noise is a random variable, either bandwidth or power levels can be assigned in an optimised way. For all three cases, the optimum schedule of resource allocation is derived including which sources are to be encoded and transmitted. Additionally, performance bounds on the distortion are derived for systems with large number of users. Fixed resource assignment, optimised bandwidth allocation and optimised power control are compared for a specific distri- bution of source variances and channel noise. Significant gains of optimised resource allocation can can observed whereby the bandwidth allocation is superior to power allocation. 1 Introduction The third generation mobile radio system UMTS (Universal Mobile Telecommunication System) as well as other 3G systems are on the way to be introduced. While 2G systems such as GSM have been mainly designed and employed for speech communication, 3G 1