Chip-level differential space-time block coded direct-sequence spread-spectrum communication

We propose a simple scheme where differential space time coding is applied to chips of spread spectrum code directly. The scheme has short decoding delay because both detection and decoding can be completely performed within one symbol period. Simulations illustrate the scheme is robustness in the presence of oscillator frequency offsets and fast time-selective fading channels. Especially, the scheme exhibits better BER performance than that of conventional symbol-level differential Space-Time Coded scheme when channel coherence time is less than the symbol time since it can get more time diversity.