One of the most important pre-conditions for the success of Location-Based Services (LBS) and UMTS in general, is the possibility to prioritize services during transmission. Only in this way voice communication and other real-time applications can be insulated from the influence of heavy data transmission. The Quality-of-Service (QoS) concept deals with the relevant methods, mechanisms, and architectures.
For the LBS part, we describe all localization methods in discussion today and also cover the standardization efforts for GSM, GPRS, and UMTS. QoS mechanisms are presented in detail. One big part of this work concerns scheduling mechanisms, which are a very important component in the shared use of network resources, especially in times of high utilization. Overbooking of transmission capacities, also called overprovisioning, is handled in detail. This is the QoS method currently used almost exclusively in the Internet.
This work presents existing QoS mechanisms proposed by the IETF and the 3GPP QoS architecture. The insights elaborated, lead to the proposal of a new QoS architecture for UMTS, which permits to prioritize real-time applications such as voice and at the same time differentiate LBS applications.
Simulation examples presented in this work show that overprovisioning can only be employed within certain boundaries. If there is only little differentiation between applications, an increase of bandwidth in the network can also be a solution to the QoS problem. However, if only a small class of high priority packets exists, the situation changes. Now, a lot more bandwidth would have to be used in order to reach the delay times achieved by the employment of QoS mechanisms.
Performance evaluations of QoS mechanisms and the proposed QoS architecture for UMTS should contribute to the success of LBS applications in UMTS.