  The collision channel without feedback (CCw/oFB) model introduced by Massey
and Mathys, depicts a scenario in which M users share a thermal noise-free
communication channel with random relative time offsets among their clocks.
This paper considers an extension of this model, which allows the receiver to
use successive interference cancellation (SIC) to iteratively cancel the
interference caused by those collided packets that have been decoded by the
receiver. As the main result of this paper, we derive the zero-error capacity
region of this channel in the slot-synchronous case, and present a zero-error
capacity achieving scheme by joint protocol sequences and channel coding
design. It is shown that the negative impact on the zero-error capacity due to
a lack of time synchronization can be removed by the help of SIC. Moreover, we
characterize the protocol sequences that can be used to achieve zero-error
capacity 1 [packets/slot] by proving new results on shift-invariant sequences
and throughput-invariant sequences; these sequences have been known to achieve
zero-error capacity for the basic CCw/oFB model without SIC. This
characterization sheds light on the minimum sequence period required in order
to attain zero-error capacity 1.
