3G Handset and Network Design

CHAPTER 8

MExE-Based QoS

We have identified delay and delay variability as two components that add or subtract from user value. Some of our rich media mix is delay-tolerant but not all of it, and the part of the media mix that is the most sensitive to delay and delay variability tends to represent the highest value. Application streaming is part of our rich media mix—Application streaming implies that we have one or more applications running in parallel to our audio and video exchange.

In this chapter, we consider how handset software performance influences the quality of the end-to-end user experience.

An Overview of Software Component Value

Delay and delay variability and the ability to multitask are key elements of software component value. The job of an operating system is to sit between the software resident in the device and the device hardware (see Figure 8.1). Going back in history, an operating system such as Microsoft DOS (Disk Operating System) reads physical memory (hardware) in order to open a file (to be processed by software). In a PDA or 3G wireless handset, the operating systems to date have typically been ROM-based products. This is changing, however, because of the need to support remote reconfigurability and dynamic application downloads.

Figure 8.1 Software partitioning.

Applications are sometimes described as embedded or even deeply embedded. The more deeply ...