The Design Brief for a Multislot, Multiband, Multimode Phone

We can now summarize the design objectives for a GSM multislot GPRS phone capable
of working in several (three or four) frequency bands and capable of supporting
other modulation techniques, such as non-constant envelope, and multiplexing
(TDMA or CDMA) options.

Multiband Design Objectives:
 Design an architecture capable of receiving and generating discrete frequencies
across four frequency bands (a total of 995 × 200 kHz channels) at duplex spacings
of 45, 80, or 95 MHz while maintaining good frequency and phase stability.
To maintain sensitivity, all handsets must be capable of frequency hopping
from frame to frame (217 times a second).
 Maintain or improve sensitivity and selectivity without increasing component
count or cost.
Multislot Design Objectives:
 Manage the increase in duty cycle and improve heat dissipation.
 Manage power-level differences slot to slot.
Multimode Design Objectives:
 Find some way of delivering power efficiency and linearity to accommodate
non-constant envelope modulation.
As always, there is no single optimum solution but a number of options with relative
merits and demerits and cost/performance/complexity trade-offs.