Filtered Multitone Modulation (fmt) Technology In The Wlan Environment

Multicarrier modulation technique has recently evoked considerable interests and widespread applications for its attractive qualities in resisting multi-path effects and mitigating ISI. Taken as an example, the OFDM technique has been adopted for some formed standards and even regarded as a candidate for the coming 4G-wideband mobile communication systems. However, OFDM has some intrinsic shortcomings: its orthogonality is susceptible to be destroyed in practical transmission, thus considerable overheads (CP and virtual carriers), strict synchronization and etc. are needed. In order to avoid these disadvantages of OFDM, a new multicarrier modulation technique, named Filtered Multitone Modulation (FMT) is studied for its applications in wireless communication in this thesis, with some related aspects being investigated intensively.FMT is also a multicarrier modulation technique based on filter bank technology. The main character of this technique is the high-spectral constraint of each subcarrier which results in its non-sensitivity to frequency offset where OFDM enduring. However, FMT has inter-symbol interferences (ISI) which are caused by the non-ideal subchannel filters. ISI has to be eliminated by per-subchannel equalizers.Firstly, we introduced the basic concept and efficient realization of FMT system in this dissertation. FMT belongs to filter bank technology. Thus we give description of FMT system based on multirate signal processing and filter banks. Efficient realizations of both critically sampling system and non-critically sampling system are deduced.Secondly, we analyze how to design the filter bank or equavently the prototype filter. For FMT system, one of the most important coefficients is the prototype filter. Its performance affects the performance of the overall system directly. Thus, we first give the design requirements of the prototype filter. Then, we give some examples which could satisfy these requirements. Finally, we deliver a scheme on optimizing the prototype filter. Simulation results show that optimum prototype filter could achieve better error probability performance and achievable bit rates.Third, we consider how to design the subcarrier equalizers. FMT system should add subcarrier equalizers at the output of the receiver to compensate ISI introduced by...