32-bit CRCs might be insufficient for WiFi

A new paper suggests CRCs might not be enough for WiFi.

Is It Time to Upgrade From CRC-32?  /  Mohit Balany; Craig Partridge
(IEEE Xplore / paywall)

The authors set up a WiFi network with fault injection (aluminum foil helped here) and found that the types of bit faults they were injecting slipped past the HD of IEEE CRC-32.  Their data suggests, but did not test, that an alternate 32-bit CRC would not be sufficient. However, they did not seem to take into account that other CRCs have a better HD performance for sparse burst faults, which is suggested would be relevant by their Figure 5.

That having been said, CRCs not being enough for any radio transmission is not a huge surprise since it is a much more fault-prone transmission medium than copper or optical fiber.

Paper Abstract:

IEEE CRC-32 is widely used in data communications to detect transmission errors. The decision to use CRC-32 was made in the 1970s, based on studies that compared the performance of various 32-bit CRCs on relatively small (2 000 bit) packets subjected to errors described by a renewal process. In today’s networks we often see far larger packets (8 000 bits or more) and experiments have shown that errors do not fit a renewal process. The world has changed. To get a sense of that change, we captured 1 900 gigabit WIFI (802.11n) transmissions errors to better understand error distributions and patterns. Our data suggest that a considerable fraction of errors could slip past IEEE CRC-32. It may soon be time to consider a new generation of error codes.