Title :
A Wideband Pulse-Modulated Polar Transmitter Using Envelope Correction for LTE Applications
Author :
Ken-Fu Liang ; Hao-Shun Yang ; Chun-Wei Chang ; Jau-Horng Chen
Author_Institution :
Dept. of Eng. Sci. & Ocean Eng., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
The pulse-modulated polar transmitter (PMPT) uses the envelope information to pulse modulate the phase information to implement a highly linear and highly efficient polar transmitter. The bandwidth of the PMPT is primarily determined by the pulsewidth modulation sampling frequency of the envelope information. For wide bandwidth applications such as long-term evolution (LTE), finite rise and fall times of the RF pulses distort the envelope information. In this paper, the nonideal RF pulses are analyzed and an envelope correction method is proposed to reduce the distortion in wide bandwidth applications using the PMPT architecture. For validation, a cellular-band prototype transmitter system was constructed using commercially available components. Using a 20-MHz bandwidth 16-QAM LTE signal at 836.5 MHz, the prototype transmitter achieved an output power of 22.7 dBm and drain efficiency of 33% while passing the spectral requirements of the LTE standard.
Keywords :
Long Term Evolution; pulse width modulation; quadrature amplitude modulation; radio transmitters; 16-QAM LTE signal; LTE standard; PMPT; bandwidth 20 MHz; cellular-band prototype transmitter system; efficiency 33 percent; envelope correction method; envelope information; fall times; finite rise times; frequency 836.5 MHz; long-term evolution; nonideal RF pulses; phase information; pulse-modulated polar transmitter; pulsewidth modulation sampling frequency; spectral requirements; Bandwidth; Long Term Evolution; Power generation; Pulse width modulation; Radio frequency; Radio transmitters; Microwave amplifiers; PA linearization; polar transmitters; power amplifiers (PAs); radio transmitters;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2015.2444837