The performance analysis for ambient backscatter communication systems is fundamentally different from that of traditional communication systems. The carrier signal of backscatter communication is opportunistically exploited from the existing active radio-frequency communication systems. As it is vulnerable to channel variations, different detection and encoding mechanisms have been proposed and analyzed to improve the system throughput or ergodic capacity. In this chapter, we have focused on the analysis of signal detection and bit-error rate (BER) performance for backscatter communication. We have reviewed the different system models for backscatter communication systems and various signal detection approaches under different resource and physical constraints.