  Rateless codes have been shown to provide robust error correction over a wide
range of binary and noisy channels. Using a stochastic geometry model, this
paper studies the performance of rateless codes in the cellular downlink and
compares it with the performance of fixed-rate codes. For the case of Rayleigh
fading, an accurate approximation is proposed for the distribution of the
packet transmission time of $K$-bit information packets using rateless codes.
The two types of channel coding schemes are compared by evaluating the typical
user and per-user success probability and the rate. Based on both the
analytical results and simulations, the paper shows that rateless coding
provides a significant throughput gain relative to fixed-rate coding. Moreover
the benefit is not restricted to the typical user but applies to all users in
the cellular network.
