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Title: A Digital Predistortion Scheme Exploiting Degrees-of-Freedom for Massive MIMO Systems
The primary source of nonlinear distortion in wireless transmitters is the power amplifier (PA). Conventional digital predistortion (DPD) schemes use high-order polynomials to accurately approximate and compensate for the nonlinearity of the PA. This is not practical for scaling to tens or hundreds of PAs in massive multiple-input multiple-output (MIMO) systems. There is more than one candidate precoding matrix in a massive MIMO system because of the excess degrees-of-freedom (DoFs), and each precoding matrix requires a different DPD polynomial order to compensate for the PA nonlinearity. This paper proposes a low-order DPD method achieved by exploiting massive DoFs of next-generation front ends. We propose a novel indirect learning structure which adapts the channel and PA distortion iteratively by cascading adaptive zero forcing precoding and DPD. Our solution uses a 3rd order polynomial to achieve the same performance as the conventional DPD using an 11th order polynomial for a 10010 massive MIMO configuration. Experimental results show a 70% reduction in computational complexity, enabling ultra-low latency communications.  more » « less
Award ID(s):
1564148
NSF-PAR ID:
10057391
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
IEEE International Conference on Communications
ISSN:
1550-3607
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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