Saturation Approach for Dual-Band Transmission with Pre-Distortion for PA Efficiency Increase

Abstract

Current wireless communication systems demand high data transmission throughput. To comply with this requirement, multiple concurrent communication channel usage are an option. The digital pre-distortion associated with the power amplifier (PA) in high suppression guarantees the linearity and maximum efficiency for a single transmission. However, reaching a high output transmission power using more than one band is not possible because the traditional pre-distortion cannot accept a saturation level. This work focuses on showing an approach for a dual-band transmission with an equivalent envelope saturation that, contrarily to previous dual-band crest factor reductions from literature based on only amplitude information, also takes into account the phase and frequency information. The introduced idea was tested by linearizing a broadband power amplifier for two-carrier, ieee802.11n at 2.4 GHz and LTE at 3.5 GHz, concurrent transmission. Simulation results in the Cadence Virtuoso software showed gain of up to 8.8 percentage points (p.p.) in the PAE metric controlling with loss less than one p.p in EVM metric.

Keywords:
Power amplifier; digital pre-distortion; concurrent transmission; efficiency; saturation

HIGHLIGHTS

Digital pre-distortion allows a concurrent dual band communication system to improve the efficiency guarantying the linearity.

DPD saturation applied for dual band transmission improved the PA efficiency about 8 p.p.

With DPD saturation for dual band transmission, the lost in EVM metric was less than 1 p.p.

Sum and division approaches for dual band DPD saturation showed similar performances.