The Effect of the Tailbiting Restriction

Abstract- It is shown that for short and moderate relative tailbit ing lengths and high signal-to-noise ra-tios systematic feedback encoders have better bit er-ror performance than nonsystematic feedforward en-coders. Conditions for w h e n tailbiting will fail are given and it is described how the encoder starting state can be obtained for feedback encoders in both controller and observer canonical form. I. SYSTEMATIC VERSUS NONSYSTEMATIC TAILBITING ENCODERS Comparing the bit error performance between tailbiting codes encoded by systematic and nonsystematic encoders [l] shows that for a bad channel systematic encoders, feedforward or feedback, give the best performance. Simulations also show that the best encoders to use when the channel quality is un