Battery Bandwidth as a Constraint on Uplink Offered Traffic

The other obvious determining factor of uplink offered traffic is battery bandwidth.
Battery bandwidth is the ability of a battery to deliver a certain amount of instantaneous
RF peak energy, which translates into instantaneous uplink bit rate, and a certain
amount of sustained energy, which will determine session length/session
persistency. Peak instantaneous RF power is constrained anyway by the regulatory
authority and will typically be either a maximum of 250 mW (Class III) or 125 mW
(Class IV). We also need to add in the source coding and channel coding. This is not
particularly significant for encoding but very significant for decoding, as we will see
later in the chapter.