Welcome to Masayoshi Tanaka  Website  

Research activities of wireless & satellite communications in the following laboratories.
-  College of Industrial Technology, Nihon University, 
     Department of Electrical and Electronic
     Engineering.​
-  NTT Electrical Communications Laboratories.
  

Improving the power efficiency of a power amplifier (HPA) is a major concern, because power resources are limited for wireless communications equipment. It is particularly desirable therefore to develop a high-power amplifier system effective in achieving high-efficiency at a reasonable cost.

 

In general, HPAs are highly efficient near the nonlinear saturation region.

 

A multi-carrier system must possess linearity since its carriers undergo common amplification. Linearity is generally critical in satellite-on-board devices, especially in a high power amplifier (HPA), which is required to operate as near the saturation region as possible to raise efficiency within the range that satisfies system requirements.

 

 

Hence, degradation in linearity lowers the quality of communications or decreases the maximum number of access channels.

 

To address these issues, we are investigating the following items.

(1) Pre-distortion linearizer
(2) Compensation by error correction coding 
(3) Modulation scheme immune to nonlinear distortion