TR2015-004

Concurrent Multiband Digital Outphasing Transmitter Architecture Using Multidimensional Power Coding

    •  Chung, S., Ma, R., Shinjo, S., Nakamizo, H., Parsons, K., Teo, K.H., "Concurrent Multiband Digital Outphasing Transmitter Architecture Using Multidimensional Power Coding", IEEE Transactions on Microwave Theory and Techniques, DOI: 10.1109/​TMTT.2014.2387845, Vol. 63, No. 2, pp. 598-613, February 2015.
      BibTeX TR2015-004 PDF
      • @article{Chung2015feb,
      • author = {Chung, S. and Ma, R. and Shinjo, S. and Nakamizo, H. and Parsons, K. and Teo, K.H.},
      • title = {Concurrent Multiband Digital Outphasing Transmitter Architecture Using Multidimensional Power Coding},
      • journal = {IEEE Transactions on Microwave Theory and Techniques},
      • year = 2015,
      • volume = 63,
      • number = 2,
      • pages = {598--613},
      • month = feb,
      • doi = {10.1109/TMTT.2014.2387845},
      • issn = {0018-9480},
      • url = {https://www.merl.com/publications/TR2015-004}
      • }
  • MERL Contact:
  • Research Areas:

    Communications, Electronic and Photonic Devices

Abstract:

All-digital outphasing transmitter architecture using multidimensional power coding (MDPC) is proposed for non-contiguous concurrent multiband transmission with a high power efficiency. MDPC transforms multiband digital baseband signals into multi-bit low-resolution digital signals that drive switching-mode PAs. A prototype digital outphasing transmitter consists of two 1-GHz bandwidth GaN Class-D PAs and a Chireix power combiner. The two GaN PAs are driven by bipolar RF PWM signals, which are transformed from a concurrent dual-band LTE signal by MDPC. The dual-band LTE signal with 15-MHz aggregate channel bandwidth at 240 MHz and 500 MHz frequency band is transmitted with -30 dBc and -37 dBc out-of-band emissions, respectively. Digital outphasing achieves more than two times higher coding efficiency than conventional concurrent dual-band digital transmitters with the same PAs in Class-S operation. Measured power coding efficiencies of 35.4% and 47.1% are observed with outphasing bipolar and 3-level RF PWM signals respectively, which are encoded from the dual-band LTE signal.