Envelope tracking

The need for greater efficiency arises particularly as modulation schemes become more complicated and their peak to average power ratio increases.

[3] Thus signals with a high peak to average power ratio mean that low efficiency levels are achieved, with the excess energy being wasted, ultimately as heat.

[4] In 2013, Qualcomm became the first company to ship a chip with such technology, which it claimed to be the industry’s first for 3G and 4G LTE mobile devices.

[5] R2 Semiconductor became the industry's first ET company to ship a phone with ET in the Samsung Galaxy S5 Mini.

Eta's approach increases efficiency at the cost of greater signal noise.