扫频干扰下多元频移键控与跳频通信的容量分析

Capacity analysis of M-FSK and FH in the presence of chirp jamming

为了分析宽带系统的抗干扰能力,提供抗干扰系统设计的准则,从信道容量的角度分析了扫频干扰下的跳频通信和多元频移键控(M-ary frequency shift keying,M-FSK)2种调制方式的通信性能。从理论上给出了两种调制方式的通信容量表达式,然后用仿真的方法分析了不同扫频干扰参数下的信道容量。分析了快速扫频和慢速扫频对两个系统的影响。结果表明:在快速扫频干扰影响下,跳频通信的通信性能恶化。而M-FSK具有较强的抗扫频干扰能力,其信道容量主要受到宽带噪声干扰的影响。因此,M-FSK在存在扫频干扰的情况下,能够取得更高的容量,具有更好的抗干扰能力。

The capacity of frequency hopping （FH） and M-ary frequency shift keying （M-FSK） was analyzed in the presence of chirp jamming to get the anti-jamming ability of wideband communication systems and to provide a theoretical criterion for anti-jamming systems. An analytical formulation and a simulation approach are given for the channel capacity. Simulations were performed in the presence of fast chirp jamming as well as slow jamming. The results show that the FH system performance deteriorates dramatically in the presence of fast chirp jamming. M-FSK is shown to have better anti-chirp jamming ability, with the performance mainly affected by the white Gaussian noise. Therefore, M-FSK achieves higher capacities in the presence of chirp jamming and has better anti-jamming ability.