| With the socio-economic development, the people's requirement for wireless communication becomes larger and larger, especially for wireless multimedia communication. The harsh wireless channel environment limits the improvement of the data rate. In oder to overcome the restraint, the virtual MIMO-OFDM technique was proposed. This technique not only increases the data rate and the capacity of the system, but also overcome the physics limitation of the terminal has the difficault to integrate multiple antennas.People have done a lot of studies on the MIMO-OFDM technique, and this technique has been widely used in all kinds of wireless communication systems. Beacasue the unique characteristics of the virtual MIMO-OFDM, there are also many problems needed to be resolved. In all those problems, the cooperative synchronization is one of the most important, and the thesis has done some researchs in this area.First, we have researched the coordination of the nodes in MAC-level. In order to implement cooperative in the nodes, we have proposed TDMA-DCF and DCF-DCF protocols, and give the numerical simulation of the protocols'latency.Second, do some researches on the frequency synchronization of the Virtual MIMO-OFDM technique. Considers there are multi frequency offsets in the signal of virtual MIMO-OFDM, the thesis gives a method to resolve the multi frequency offsets estimation. This method uses the MUSIC algorithm in the short train sequences and the simulation result shows that the method can complete the multi frequency offsets estimation.Thrid, under the environment of multi frequency offsets, the thesis firtly uses the characteristics of cooperative communication, complete pre-compensation of multi frequency offsets in the transmit end. Finally, the thesis proposes a new method for multi frequency offsets compensation. This method uses the virtual carriers in the OFDM signals and the thesis gives its performance simulation and mathematical derivation. |
PDF Full Text Request