High Throughput Constant Envelope Pre-coder for Massive MIMO Systems

• This study describes a high throughput constant envelope (CE) pre-coder for Massive MIMO systems. A large number of antennas (M), in the order of 100s, serve a relatively small number of users (K) simultaneously. The stringent amplitude constraint (only phase changes) in the CE scheme is motivated by the use of highly power-efficient non-linear RF power amplifiers. We propose a scheme that computes the CE signals to be transmitted based on box-constrained regression (coordinatedescent),with an O(2MK) complexity per iteration per user symbol. A highly scalable systolic architecture is implemented, where M Processing Elements (PEs) perform the pre-coding for a system with up to K = 16 users. This systolic architecture results in a very high throughput of 500 Msamples/sec (at 500 MHz clock rate) with a gate count of 14 K per PE in 65 nm technology.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

massive mimo

pre-coding

constant envelope

gradient descent

Publikations- och innehållstyp

kon (ämneskategori)

ref (ämneskategori)