3G Handset and Network Design

CHAPTER 5

Handset Hardware Evolution

We have just described how bandwidth has become more adaptive over time—adaptive source coding, adaptive channel coding, adaptive modulation, adaptive multiplexing, and, for the future, adaptive RF channel spacing. By implication, this means that it is necessary for hardware to become more adaptive. You can take an all-purpose device like a DSP or a microcontroller and use different parts of it for different purposes. This is fine but arguably a little wasteful of resources. Alternatively, you can dynamically alter—that is, reconfigure—hardware to be reoptimized to a changed application requirement. This is the argument put forward by the makers of field programmable gate arrays (FPGAs). It is certainly true to say that if a number of processes occur sequentially, and provided FPGAs can be reconfigured sufficiently quickly, efficiency gains can be achieved.

A Review of Reconfigurability

Let's review what we mean by reconfigurability. There are three ways to define reconfigurable devices:

• Devices that are reconfigured by the vendor (often prior to shipment)
• Devices that can be reconfigured by a network
• Devices that can reconfigure themselves

Devices that are reconfigured by a vendor do not need to be connected to a network. Devices that are reconfigured by a network or reconfigure themselves include RF: infrared, copper, and optically connected devices. The design decisions to be made are as follows:

• What percentage of a product can remain ...