用于认知无线电的自适应双模跳频OFDM系统

An Adaptive Dual-mode Frequency Hopping OFDM System for Cognitive Radio

认知无线电感知的空闲频谱具有非连续、非均匀特性,对认知无线电物理层实现提出挑战。跳频正交频分复用技术(Orthogonal Frequency Division Multiplexing,OFDM)兼具跳频与OFDM二者优势,适用于宽带无线传输。提出一种自适应双模跳频OFDM系统,即把射频跳频OFDM与基带跳频OFDM相结合,根据频谱感知信息和基带处理能力自适应地在2种模式间切换,给出系统的设计规则和实现流程。分析表明该系统可提高非连续、非均匀空闲频谱的利用率,是一种可行的认知无线电物理层实现机制。

The idle spectrum sensed by cognitive radio is always discontinuous and non-uniform,it is a real challenge for cognitive radio physical realization.Frequency hopping OFDM has the advantages of both frequency hopping and OFDM,and is used in wideband wireless transmission.An adaptive dual-mode frequency hopping OFDM system,which combines RF-FH-OFDM and BB-FH-OFDM,has been proposed.Switches are carried out adaptively between the two modes based on the spectrum sensing information and the capability of baseband processing.Design rules and realizing flow chart for the system are provided.Analysis shows that it can improve the utilization ratio for those discontinuous and non-uniform idle spectrums,and can act as a practical physical realization mechanism for cognitive radio.