The computation of channel capacity with side information at the transmitter side (but not at the receiver side) requires, in general, extension of the input alphabet to a space of “strategies,” and is often hard. We consider the special case of a discrete memoryless modulo-additive noise channel = + , where the encoder observes causally the random state that governs the distribution of the noi...

We give an upper bound to the finite block length capacity of discrete time nonstationary Gaussian channel with feedback. With the aid of minimization of a quadratic form, it is proved that the feedback capacity Cn,FB(P ) and the nonfeedback capacity Cn(P ) satisfies Cn(P ) ≤ Cn,FB(P ) ≤ Cn(P∗), where P∗ is concretely given.

The channel capacity of randomly spread CDMA subject to Gaussian noise and flat fading is studied in the large-system limit under arbitrary input distributions. Using the replica method originally developed in statistical physics, we find the spectral efficiencies under both joint decoding and single-user decoding. We show that under single-user decoding, where a conditional mean estimator is f...

This is a mini-course on graph-based codes, given at the Center for Theoretical Sciences at Taipei, Taiwan, July 12-15, 2004. In practical coding theory, the main challenge has been to find codes with rates close to channel capacity and with efficient encoding and decoding algorithms. Only recently was this accomplished, theoretically for the binary erasure channel but only experimentally for t...

I n this report we study the decoding algorithms for a family of codes called LDPC codes used over the binary erasure channel (BEC). LDPC codes are able to work at rates near Shannon capacity with linear time decoding algorithms. Those linear time decoding algorithms sometimes fail even when Gaussian elimination would still be able to restore the codeword. In this report we try to experimentall...

12. Considering discrete-time channels, sketch a chart showing the following plots: (a) Continuous-valued AWGN channel capacity (bits/symbol) as a function of SNR (b) Maximal conveyed information as a function of SNR for the following alphabets: 2-PSK, 4-PSK, 16-QAM, 64-QAM The characteristic shapes of the curves and asymptotic behaviors are essential. 13. The capacity per symbol for a continuo...

We compute Shannon capacity of nonlinear channels with regenerative elements. Conditions are found under which capacity of such nonlinear channels is higher than the Shannon capacity of the classical linear additive white Gaussian noise channel. We develop a general scheme for designing the proposed channels and apply it to the particular nonlinear sine-mapping. The upper bound for regeneration...

This paper extends the near-capacity performance of serially-concatenated convolutional codes under AWGN to periodically time-varying channels. In particular, we propose serially-concatenated trellis-coded modulations (SCTCMs) that perform consistently close to channel capacity under periodic erasures as well as under AWGN, without sacrificing AWGN channel performance. The proposed 0.5 bits/sym...

We study DMC and AWGN channels when the transmitter harvests energy from the environment. These can model wireless sensor networks as well as Internet of Things. We study such channels with infinite energy buffer in the finite blocklength regime and provide the corresponding achievability and converse results. Index Terms Achievable rates, Converse, Channel Capacity, Finite Blocklength, EH-AWGN...

Energy harvesting sensor nodes are gaining popularity due to their ability to improve the network life time and are becoming a preferred choice supporting “green communication”. In this paper we focus on communicating reliably over an AWGN channel using such an energy harvesting sensor node. An important part of this work involves appropriate modeling of the energy harvesting, as done via vario...