DocumentCode :
996538
Title :
On the RF/DSP design for efficiency of OFDM transmitters
Author :
Helaoui, Mohamed ; Boumaiza, Slim ; Ghazel, Adel ; Ghannouchi, Fadhel M.
Author_Institution :
Mediatron Res. Lab., Ecole Supericure des Commun. de Tunis, Ariana, Tunisia
Volume :
53
Issue :
7
fYear :
2005
fDate :
7/1/2005 12:00:00 AM
Firstpage :
2355
Lastpage :
2361
Abstract :
In this paper, a system-level RF/digital signal processing (DSP) design approach of power-efficient orthogonal frequency-division multiplexing (OFDM) transmitters is proposed. A DSP-based low-IF architecture, which allows a significant enhancement of their power and spectrum efficiencies, is proposed. The cascade of the peak-to-average power ratio (PAPR) reduction technique, predistortion technique, and the in-phase and quadrature modulation led to impressive improvement in the power efficiency and effective linear output power of the OFDM transmitter. Measurement results carried out on an IEEE 802.11a transmitter designed and built for this experiment are presented in terms of error vector magnitude (EVM), adjacent channel leakage ratio, and power efficiency. The power stage of this transmitter uses a heterojunction bipolar InGaP transistor operating in a deeply class AB. The cascade of the PAPR reduction and baseband predistortion processing modules results in the reduction of the power backoff operation point by approximately 10 dB accompanied by a relative increase in the wireless local area network transmitter power efficiency by roughly 400% while meeting the emission mask spectrum and EVM levels demanded by the 802.11a standard.
Keywords :
IEEE standards; III-V semiconductors; OFDM modulation; digital signal processing chips; gallium compounds; heterojunction bipolar transistors; indium compounds; radio transmitters; wireless LAN; IEEE 802.11a standard; InGaP; OFDM transmitters; PARR reduction; RF/DSP design; adjacent channel leakage ratio; baseband predistortion processing; emission mask spectrum; error vector magnitude; heterojunction bipolar transistor; in-phase modulation; orthogonal frequency-division multiplexing; peak-to-average power ratio reduction; power backoff operation; power-amplifier linearization; predistortion technique; quadrature modulation; spectrum efficiency; wireless local area network; Digital signal processing; Frequency division multiplexing; OFDM modulation; Peak to average power ratio; Power generation; Predistortion; Process design; Radio frequency; Signal design; Transmitters; Peak-to-average power ratio (PAPR) reduction; power-amplifier linearization; predistortion; wireless local area network (WLAN);
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/TMTT.2005.850437
Filename :
1463356
Link To Document :
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