Physical Layer Error Characteristics Most Physical Layers( communications channels)are not well described by a simple bER parameter Most physical error processes tend to create a mix of random bursts of errors a channel with a beR of 10-7 and a average burst size of 1000 bits is very different from one with independent random errors EXample: For an average frame length of 104 bits random channel: E(Frame error rate]- 10-3 burst channel: E[Frame error rate]- 10-5 Best to characterize a channel by its Frame Error Rate This is a difficult problem for real systemsPhysical Layer Error Characteristics • Most Physical Layers ( communications channels) are not well described by a simple BER parameter • Most physical error processes tend to create a mix of random & bursts of errors • A channel with a BER of 10-7 and a average burst size of 1000 bits is very different from one with independent random errors • Example: For an average frame length of 104 bits – random channel: E[Frame error rate] ~ 10-3 – burst channel: E[Frame error rate] ~ 10-6 • Best to characterize a channel by its Frame Error Rate • This is a difficult problem for real systems