| In recent years, digital communication technology has received rapid development with the integration of mobile communications and internet, but the better performance of communication system is still required. Although various new technologies have emerged to meet the requirements, the development of modulation methods is slower. OFDM has obvious advantages in data transmission efficiency as a multi-carrier modulation technique compared with other modulation methods, which has been used in a variety of communication standards. However, the OFDM system has two major drawbacks:high Peak to Average Power Ratio (PAPR) and sensitivity to frequency shift, which limit performances of OFDM.TS-NMT is a novel multi-carrier modulation technology. Both TS-NMT and OFDM are multi-carrier modulation technologies. The main difference between them is that each sub-carrier has a time delay to the starting point of the symbol, which is called Time-Shift. As a result of the Time-Shift, the different frequcncy sub-channels are no longer orthogonal, which provides some excellent performances to TS-NMT and also leads to new signal processing problems. Recent researches have proved that the superiority of TS-NMT to traditional orthogonal methods in transmission efficiency. Computer simulations and physical wired and wirelss experiments have proved that TS-NMT is superior to OFDM in transmission efficiency and other performances. OFDM has become the major modulation technology, so the theoretical and experimental analysis and comparison between TS-NMT and OFDM are necessary. The main contributions are the quantitative analysis and comparison between TS-NMT and OFDM and the applications of TS-NMT. The main work is as follows:(1) The relevant issues and resolutions during modulation and demodulation are analyzed, such as the Inter Sub-Symbol Intefrence (ISSI) and ill-conditionality in the equation group of TS-NMT. Based on the wave structure of TS-NMT, the characteristics of time domain and frequency domain compactness are proposed. Due to the Time-Shif character of TS-NMT, many symbols of the single carrier modulation are compacted into one symbol in time domain. Due to the non-orthogonality character of TS-NMT, sub-channels of TS-NMT are closer in frequency domain to reduce the bandewidth greatly. The non-orthogonal idea has been used in general signal processing. The method of Fourier Series with fractional frequency intervals (FFFS) for the decomposition of signals is proposed, and experiments show that FFFS can provide better performance than FS.(2) The quantitative analysis and comparison between TS-NMT and OFDM are made and listed as follows:①According to the principle of constellation diagram analysis, the formulaηNS.o of the spectrum efficiency ratio of the sub-channel is derived. When the number of the sub-carriers in one sub-channel is 4～60,ηNS o is between one and five. Based on the frequency domain compactness,ΔfN is smaller thanΔfo, whereΔfN andΔfo are the frequency intervals of TS-NMT and OFDM respectively. The bandwidth of TS-NMT could be compressed to improve the spectrum efficiency.②Based on the low probability of adding sub-carriers in the same phase, the maximum amplitude of TS-NMT signal increases slower than the number of sub-carriers. TS-NMT can provide better PAPR than OFDM.③The method of converting the error caused by frequency shift to equivalent noise power is proposed. The theoretical and experimental results prove that TS-NMT has better capability of tolerating frequency shift.④Based on the analysis of spectrum efficiency, it can be proven that, the energy consumption of TS-NMT is less than OFDM according to the constellation diagram analysis.(3) One of the key technologies of WSN is how to improve the efficiency of limited battery power in a single node. Based on the theoretical analysis of energy performance and lower power consumption characteristics of TS-NMT, the idea of applying TS-NMT to WSN is proposed. The theoretical analysis and experiments results prove that TS-NMT is superior to QPSK and the power consumption of one bit is lower. The result proves the practicability of TS-NMT applying to WSN.(4) Finally, computer simulations of TS-NMT in VDSL loop are made. The simulation environment, including the channel model and noise model, is established. The simulation comparison between TS-NMT and DMT is made in the same experimental conditions. Experimental results show that, the transmission performance of TS-NMT is better than DMT in VDSL loop. The result also proves the practicability of TS-NMT. Based on the characteristic of frequency domain compactness of TS-NMT, the users are divided into groups to reduce the self-FEXT noise for high bit rate transmission.
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