Markku Kiviranta, Aarne Mämmelä

VTT Electronics

Oulu, Finland

and

Danijela Čabrić, David A. Sobel, Robert W. Brodersen

Berkeley Wireless Research Center,

University of California, Berkeley, CA

IEEE MILCOM, Atlantic City, New Jersey, October 17-20, 2005.

In this paper we study the suitability of constant envelope multi-carrier modulation technique for the implementation of 1Gbps wireless link at 60 GHz. This technique combines orthogonal frequency division multiplexing (OFDM) and phase modulation (PM) where: (1) PM creates a constant envelope signal which allows high power amplifier to operate near saturation levels thus maximizing power efficiency, (2) OFDM increases robustness to multipath fading. Since OFDM-PM symbols satisfy symmetry property, maximumratio combiner (MRC) can be used at the receiver. Our simulations show that in an AWGN channel at bit error level 10-3, the OFDM-PM with MRC has about 0.8 dB performance loss compared to OFDM or single carrier minimum shift keying (MSK). For Rician fading channels, we find that OFDM-PM performs comparably to MSK and outperforms uncoded OFDM. Furthermore, we show that both OFDM and OFDM-PM have similar bit error distribution characteristics, and thus the performance of OFDM-PM can be improved by the use of water-filling or coding techniques.

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