Third generation mobile communications: Capacity of a time-division duplex code-division multiple access cellular system.

摘要

This thesis describes the work done in evaluating the capacity of a multi-service third generation (3G) wireless communication system based on the Universal Mobile Telecommunication System (UNITS). More specifically, the study presented in these pages examines the Time Division Duplex (TDD) paradigm supported by the 3G Partnership Project (3GPP).; The goal is to establish the probability that a new connection attempt be successful as a function of the instantaneous load on the network. The sought capacity is evaluated with the help of an analytical model and a simulation tool. Both tools used a so-called system-level approach. The model and the simulator were developed based on 3GPP's standard and available data from link-level simulations.; Some of the significant results presented are: (1) A maximum of around 7 to 9 orthogonal codes can be used per timeslot. (2) A UMTS TDD CDMA system should be used in pico- and micro-cellular environments in order to support efficient data transmissions. (3) The multicode interference is often wrongfully neglected in capacity studies. (4) Capacity is downlink interference-limited, even with a modest MUD efficiency.