RF transmitter architecture investigation for power efficient mobile WiMAX applications

Wireless broadband digital communication systems with high spectral efficiency suffer from severe power efficiency problem. Peak-to-Average Power Ratio is reported up to 12dB for WiMAX 802.16e systems implementing OFDM IFFT-1024 and 64-QAM modulation. In this work, outphasing (LINC) and polar transmitter architectures are investigated and compared with direct conversion (DC) architecture. Complete system solution targeting 23dBm output power is evaluated. System level simulation result shows that, with linear power combiner, LINC consumes more power than DC if non-clipping modulation scheme used. And polar system has stringent 3 degree phase matching and 0.5 dB gain matching requirements to meet EVM and spectrum mask specifications.

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