US 9,813,085 B1
Closed loop digital pre-distortion
Paul Brandon Butler, San Jose, CA (US); James Gardner, San Ramon, CA (US); Niranjan Talwalkar, San Jose, CA (US); and Burcin Baytekin, Milpitas, CA (US)
Assigned to QUALCOMM Incorporated, San Diego, CA (US)
Filed by QUALCOMM Incorporated, San Diego, CA (US)
Filed on Sep. 23, 2016, as Appl. No. 15/275,317.
Int. Cl. H04B 1/04 (2006.01); H04B 7/0413 (2017.01); H04B 17/13 (2015.01); H04B 7/06 (2006.01); H04L 5/22 (2006.01)
CPC H04B 1/0458 (2013.01) [H04B 1/0475 (2013.01); H04B 7/0413 (2013.01); H04B 7/0626 (2013.01); H04B 17/13 (2015.01); H04L 5/22 (2013.01)] 21 Claims
OG exemplary drawing
 
1. An apparatus for wireless communication, the apparatus comprising:
a power amplifier coupled to a transmit path of the apparatus;
a switch to selectively couple an output of the power amplifier to a receive path of the apparatus; and
a pre-distortion circuit coupled to an input of the power amplifier by the transmit path and coupled to the switch by the receive path, the pre-distortion circuit configured to:
if the power amplifier is on:
output, on the transmit path, a first signal; and
receive, via the receive path, a first feedback signal generated based on the first signal;
if the power amplifier is off:
output, on the transmit path, a second signal; and
receive, via the receive path, a second feedback signal generated based on the second signal;
determine one or more coefficients based at least in part on the first and second feedback signals; and
apply the one or more coefficients to a data signal to generate a third signal.