TITLE:
Opportunistic Error Correction: When Does It Work Best for OFDM Systems?
AUTHORS:
Xiaoying Shao, Cornelis H. Slump
KEYWORDS:
Water-Filling; Opportunistic Error Correction; OFDM; ADC; Frequency Selective Fading
JOURNAL NAME:
International Journal of Communications, Network and System Sciences,
Vol.6 No.11,
November
19,
2013
ABSTRACT: The water-filling algorithm enables an energy-efficient OFDM-based transmitter
by maximizing the capacity of a frequency selective fading channel.
However, this optimal strategy requires the perfect channel state
information at the transmitter that is not realistic in wireless
applications. In this paper, we propose opportunistic error correction to
maximize the data rate of OFDM systems without this limit. The key
point of this approach is to reduce the dynamic range of the
channel by discarding a part of the channel in deep fading. Instead of
decoding all the information from all the sub-channels, we
only recover the data via the strong sub-channels. Just like the
water-filling principle, we increase the data rate over the stronger
sub-channels by sacrificing the weaker sub-channels. In such a case, the
total data rate over a frequency selective fading channel can be
increased. Correspondingly, the noise floor can be increased to
achieve a certain data rate compared to the traditional coding
scheme. This leads to an energy-efficient receiver. However,
it is not clear whether this method has advantages over the joint
coding scheme in the narrow-band wireless system (e.g. the channel with a
low dynamic range), which will be investigated in this paper.