On the dirty paper channel with fading dirt

2014 IEEE International Symposium on Information Theory

2014

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The impact of phase fading on the classical Costa's dirty paper coding channel is studied. We consider a variation of this channel model in which the amplitude of the interference sequence is known at the transmitter while its phase is known at the receiver. Although the capacity of this channel has already been established, it is expressed using an auxiliary random variable and as the solution of a maximization problem. To circumvent the difficulty evaluating capacity, we derive alternative inner and outer bounds and show that the two expressions are to within a finite distance. This provide an approximate characterization of the capacity which depends only on the channel parameters. We consider, in particular, two distributions of the phase fading: circular binomial and circular uniform. The first distribution models the scenario in which the transmitter has a minimal uncertainty over the phase of the interference while the second distribution models complete uncertainty. For circular binomial fading, we show that binning with Gaussian signaling still approaches capacity, as in the channel without phase fading. In the case of circular uniform fading, instead, binning with Gaussian signaling is no longer effective and novel interference avoidance strategies are developed to approach capacity.

Section: Introductionmentioning

confidence: 99%

The impact of phase fading on the dirty paper coding channel

2014 IEEE International Symposium on Information Theory

2014

Self Cite

“…For this reason, neither closed form expressions nor numerical evaluations of capacity are known. Outer and inner bounds to the capacity are derived in [5] while achievable rates under Gaussian signaling and lattice strategies are derived in [6]. The fading dirty paper channel in which the fading values is constant trough successive channel uses is studied in [7].…”

Section: Introductionmentioning

confidence: 99%

On capacity of the dirty paper channel with fading dirt in the strong fading regime

2014 IEEE Information Theory Workshop (ITW 2014)

2014

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The classical "writing on dirty paper" capacity result establishes that full interference pre-cancellation can be attained in Gel'fand-Pinsker problem with additive state and additive white Gaussian noise. This result holds under the idealized assumption that perfect channel knowledge is available at both transmitter and receiver. While channel knowledge at the receiver can be obtained through pilot tones, transmitter channel knowledge is harder to acquire. For this reason, we are interested in characterizing the capacity under the more realistic assumption that only partial channel knowledge is available at the transmitter. We study, more specifically, the dirty paper channel in which the interference sequence in multiplied by fading value unknown to the transmitter but known at the receiver. For this model, we establish an approximate characterization of capacity for the case in which fading values vary greatly in between channel realizations. In this regime, which we term the "strong fading" regime, the capacity pre-log factor is equal to the inverse of the number of possible fading realizations.

“…In [9], we show the approximate capacity of this model for some classes of the phase fading. Achievable rates under Gaussian signaling are derived in [10] for the case of Gaussian distributed fast fading. These attainable rates are also compared to lattice coding strategies and some numerical observations are provided on the performance of these various coding choices.…”

Section: Introductionmentioning

confidence: 99%

On Capacity of the Writing Onto Fast Fading Dirt Channel

IEEE Trans. Wireless Commun.

2018

The "Writing onto Fast Fading Dirt" (WFFD) channel is investigated to study the effects of partial channel knowledge on the capacity of the "writing on dirty paper" channel. The WFFD channel is the Gel'fand-Pinsker channel in which the output is obtained as the sum of the input, white Gaussian noise and a fading-times-state term. The fading-times-state term is equal to the element-wise product of the channel state sequence, known only at the transmitter, and a fast fading process, known only at the receiver. We consider the case of Gaussian distributed channel states and derive an approximate characterization of capacity for different classes of fading distributions, both continuous and discrete.In particular, we prove that if the fading distribution concentrates in a sufficiently small interval, then capacity is approximately equal to the AWGN capacity times the probability of this interval. We also show that there exists a class of fading distributions for which having the transmitter treat the fadingtimes-state term as additional noise closely approaches capacity. Although a closed-form expression of the capacity of the general WFFD channel remains unknown, our results show that the presence of fading can severely reduce the usefulness of channel state knowledge at the transmitter.