13,548 research outputs found
Design guidelines for spatial modulation
A new class of low-complexity, yet energyefficient Multiple-Input Multiple-Output (MIMO) transmission techniques, namely the family of Spatial Modulation (SM) aided MIMOs (SM-MIMO) has emerged. These systems are capable of exploiting the spatial dimensions (i.e. the antenna indices) as an additional dimension invoked for transmitting information, apart from the traditional Amplitude and Phase Modulation (APM). SM is capable of efficiently operating in diverse MIMO configurations in the context of future communication systems. It constitutes a promising transmission candidate for large-scale MIMO design and for the indoor optical wireless communication whilst relying on a single-Radio Frequency (RF) chain. Moreover, SM may also be viewed as an entirely new hybrid modulation scheme, which is still in its infancy. This paper aims for providing a general survey of the SM design framework as well as of its intrinsic limits. In particular, we focus our attention on the associated transceiver design, on spatial constellation optimization, on link adaptation techniques, on distributed/ cooperative protocol design issues, and on their meritorious variants
Achievable Information Rates for Coded Modulation with Hard Decision Decoding for Coherent Fiber-Optic Systems
We analyze the achievable information rates (AIRs) for coded modulation
schemes with QAM constellations with both bit-wise and symbol-wise decoders,
corresponding to the case where a binary code is used in combination with a
higher-order modulation using the bit-interleaved coded modulation (BICM)
paradigm and to the case where a nonbinary code over a field matched to the
constellation size is used, respectively. In particular, we consider hard
decision decoding, which is the preferable option for fiber-optic communication
systems where decoding complexity is a concern. Recently, Liga \emph{et al.}
analyzed the AIRs for bit-wise and symbol-wise decoders considering what the
authors called \emph{hard decision decoder} which, however, exploits \emph{soft
information} of the transition probabilities of discrete-input discrete-output
channel resulting from the hard detection. As such, the complexity of the
decoder is essentially the same as the complexity of a soft decision decoder.
In this paper, we analyze instead the AIRs for the standard hard decision
decoder, commonly used in practice, where the decoding is based on the Hamming
distance metric. We show that if standard hard decision decoding is used,
bit-wise decoders yield significantly higher AIRs than symbol-wise decoders. As
a result, contrary to the conclusion by Liga \emph{et al.}, binary decoders
together with the BICM paradigm are preferable for spectrally-efficient
fiber-optic systems. We also design binary and nonbinary staircase codes and
show that, in agreement with the AIRs, binary codes yield better performance.Comment: Published in IEEE/OSA Journal of Lightwave Technology, 201
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