Equalization and Coding for Ultra Low Delay Wireless Digital Communication - A Comparison

Inhalt:
Orthogonal Frequency Division Multiplexing (OFDM) is widely used in current wireless standards. In the upcoming 5G mobile communications standardization, one important focus will be ultra low latency communication. For such use cases, however, OFDM is a poor choice, because it can only unfold its full potential if used in combination with powerful channel codes. If there is a tight constraint on latency, this may not be possible. In this paper, we compare OFDM with single-carrier transmission for very short block lengths and different code rates. The single-carrier receive signal is equalized using either a turbo detection scheme or a so-called matched decoder, which achieves channel equalization and decoding at the same time. Additionally, matched decoding allows for a flexible trade-off between complexity and performance. We show that for low delay applications, single-carrier transmission allows for much higher power efficiencies. This effect is even more pronounced for higher code rates.