An achievable rate for the discrete memoryless relay channel with receiver-transmitter feedback is proposed based on Block-Markov superposition encoding. The achievable rate can also be extended to Gaussian channels. A second achievable rate for the Gaussian relay channel based on a Schalkwijk-Kailath type scheme is presented. For some channels both achievable rates strictly improve upon all pr...

Combined channel coding and digital modulation (multilevel codes) yield power and bandwidth efficient digital transmission schemes. It is known that systems optimised for the Gaussian channel are not optimum for fading channels and vice versa [I]. We apply iterative multistage decoding of multilevel codes which leads to good prformance for both Gaussian and fading channels at bit error rates (B...

In this paper, we derive achievable rates for arbitrary network topologies consisting of ‘cheap’ nodes. A node is labeled ‘cheap’ if its radio can only operate in TDD mode when transmitting and receiving in the same frequency band. Two main results are shown. The first result provides an achievable rate for the channel with either continuous alphabet or discrete channel. The second result provi...

Suppose that we want to send a description of a source to two listeners through a Gaussian broadcast channel, where the channel is used once per each source sample. The minimum possible distortion D 2 that the bad receiver can obtain is D 2 = D(C 2), where D() is the distortion-rate function of the source and C 2 is the capacity of the bad channel. We want to nd the smallest achievable distorti...

Research in distributed video coding for low complexity encoding has shown that without knowledge of the correlation between source and side information (i.e. the behavior of the virtual dependency channel), the performance is substantially below that of well known state-of-the-art video coders. In this paper we investigate the modeling of the virtual channel for a pixel-based Wyner-Ziv coding ...

A novel Joint Source Channel Scheme for the two user Gaussian Broadcast channel is developed here. The scheme transmits a Bivariate Gaussian Source over a Discrete Memoryless Additive White Gaussian Noise Channel. The scheme belongs to the family of codes termed Nested Quantization. The ultimate theoretical communication limits of the Gaussian Broadcast channel are given and the different codin...

We show that the gain for using a waterfilling power allocation instead of a flat allocation over non-singular channel components is negligible at high signal-to-noise ratios. Consider the standard additive noise communication channel with a quadratic power constraint. Although waterfilling provides the optimal input distribution for Gaussian noise channels, sub-optimal distributions are often ...

A communication environment with multiple transmitters and multiple receivers is inherently a competitive environment. The aim of this thesis is to illustrate the role of competition and the value of cooperation in a multi-user communication environment from an information-theoretical perspective. Various scenarios will be treated, including the multiple access channel where receivers cooperate...

The capacity of deterministic, complex and discrete time memoryless Additive White Gaussian Noise (AWGN) channel under three constraints, namely, channel input average power, channel input amplitude and delivered power at the channel output is considered. The delivered power constraint is modelled as a linear combination of even-moment statistics of the channel input being larger than a thresho...

We consider the notion of canonical attacks, which are the cryptographic analog of the canonical forms of a one-mode Gaussian channel. Using this notion, we explore the connections between the degradability properties of the channel and its security for quantum key distribution. Finally, we also show some relations between canonical attacks and optimal Gaussian cloners.