The Key Technology For The Wideband Networking Waveform

In broadband high-speed wireless communication systems, OFDM is a multi-carrier data communication technology which has broad application prospect. It has the advantages of a high utilization of frequency, elimination of anti-inter-symbol interference and a strong ability of anti-fading. However, the traditional OFDM also has the disadvantage of high peak-to-average power ratios(PAPRs), and being sensitive to the frequency offset and phase noise. Aiming at the problem that OFDM has large amplifier input offset, Some scholars summarized the traditional shortcomings of reducing PAPR algorithm and proposed a technique named constant envelope multi-carrier modulation. In recent years, the U.S. Department of Defense (DOD) for the Joint Tactical Radio System (JTRS) has developed a new protocol standard waveform - broadband networking waveform (WNW), and planned to launch it into battlefield in 2010. Constant envelope OFDM (CE-OFDM) is a key technology of the Joint Tactical Radio System (JTRS) wideband network waveform (WNW) for performance optimization. Constant envelope OFDM (CE-OFDM) can theoretically reduce the PAPR to OdB, which can use the non-linear power amplifier, thus saving much power than OFDM.This paper first introduces the traditional methods of reduction OFDM's peak-to-average ratios(PAPRs), and the basic charicteristic that Constant envelope OFDM (CE-OFDM) can reduce PAPRs to OdB by way of signal transformation. Then this article detailedly discusses the theory of Constant Envelope OFDM and the algorithms of each module in transfer and receiver.This paper focuses on the difficulties of the project—the phase demodulation algorithm, analysing and improving the defect for the primary algorithm, then develops a more advanced phase demodulation receiver. This project simulates the advanced algorithm of constant envelope OFDM on the GNU Octave software platform, validating the feasibility of Constant Envelope OFDM.The simulation results show that in the AWGN channel and multipath fading channels the performance of constant envelope OFDM is well. This project implement constant envelope OFDM in the hardware platform for the broadband high-speed radio . Finally, the article draws conclusion of this project and puts forward the expectation of application prospects for Constant Envelope OFDM in broadband high-speed wireless communication environment.