Multiple accessing for the collision channel without feedback

We consider asynchronous multiple accessing without feedback over the collision channel. Redundant coding is used to overcome user interference which causes erasures for collided packets. The channel has a sum capacity of e^-1and a sum cutoff rate of 0.295. The best codes are long constraint length rate 1/3 convolutional encoders which achieve a sum throughput up to the sum cutoff rate using an easy-to-implement forward search decoding algorithm. In the presence of additive Gaussian noise, the same redundant coding can save, at hardly any extra cost, about 6 dB of signal-to-noise ratio.