Carrier Ofdm System Aggregation

The mobile communication development has created an increasing demand for high data rate and large band. Although the transmission rate is greatly improved by the 3G application, some services, such as the Multimedia and Internet, require a higher transmission speed. In order to achieve this aim, it is needed not only to heighten spectrum efficiency but also to expand bandwidth in the limited frequency resources.The carrier aggregation is regarded as the key technology for bandwidth expansion when the quasi-4G system that LTE and IEEE 802.16 transform toward IMT-advanced. As a research hotspot in the 3GPP LTE-Advanced and 802.16e, it has obtained lots of attentions. OFDM is one of the common key technologies in LTE and WiMAX. So it is important to study carrier aggregation in OFDM system.The carrier aggregation is introduced in the paper firstly. Then, there are two carrier aggregation methods proposed --- multi-carrier aggregation and direct wideband aggregation. They are compared with the performance of PAPR and BER. The results indicate that the performance of direct wideband mode is better than the other. Due to the better flexibility and backward compatibility, multi-carrier aggregation is supposed to be retained. The combined use of the two aggregations should be considered in future system.Based on the analysis of adjacent-channel interference and out-of-band power, a few suggestions are presented in the thesis. For instance, the reuse of guard band can get gain in system capacity; the principle of carrier spacing is set to ensure backward compatibility with the earlier equipment. In the end, the design of variable-length tree resources naming is given to reduce control signaling overhead in carrier aggregation. These provide low-level simulation foundation for the application of carrier aggregation.