Performance evaluation of the OFDM modulation in IEEE 802.11-based wireless industrial networks

IEEE-802.11 standard, as the dominant wireless technology, has extended its usage to Industrial Networks. Various physical layer modulation schemes have been defined in the standard, but only the simplest ones, like DBPSK, has been thoroughly studied in the literature. OFDM on the other hand, has proven performance in fading channels, which is a common phenomenon in noisy industrial environment. In this paper, performance evaluation of the OFDM modulation, in various network scenarios including number of competing nodes, packet payload, SNR, and retry limit, has been thoroughly studied. Delay metrics including average, maximum, and jitter has been considered. Simulation results show significant outperformance of OFDM for typical short packet payloads in industrial networks (8 to 32 Bytes). It is worth noting that at larger data payloads (e.g. 64-Byte and above), the simple DBPSK provides better performance at noisy and fading environment.