With the advent of massive data outputs at a regular rate, admittedly, signal processing technology plays an increasingly important role. Nowadays, signals are not merely restricted to the physical domain, they have been extended to cover a much wider range of statistical sources (including financial signals, graph signals). Under the general assumption of discrete statistical signal sources, w...

Successive interference cancellation (SIC), in conjunction with orthogonal convolutional codes, has been shown to approach the Shannon capacity for an AWGN channel [1]. However, multi-cell fading wireless channels induce error in the amplitude and phase estimates required to perform perfect cancellation of the interference. By combining SIC with an appropriate power control algorithm [2], we sh...

Consider communication over a channel whose probabilistic model is completely unknown vector-wise and is not assumed to be stationary. Communication over such channels is challenging because knowing the past does not indicate anything about the future. The existence of reliable feedback and common randomness is assumed. In a previous paper it was shown that the Shannon capacity cannot be attain...

This paper studies the optimization of the effective channel capacity of wideband code division multiple access (WCDMA) systems under Rayleigh fading environments. Firstly, the results for Shannon capacity of fading channels with channel side information are reviewed, where the capacity is achieved by using an optimal power control scheme. Secondly, an optimal interference threshold α0 is set f...

The tendency of semidefinite programs to compose perfectly under product has been exploited many times in complexity theory: for example, by Lovász to determine the Shannon capacity of the pentagon; to show a direct sum theorem for non-deterministic communication complexity and direct product theorems for discrepancy; and in interactive proof systems to show parallel repetition theorems for res...

This work investigates the achievable information rate with the state-of-the-art turbo coding and intensity modulation / direct detection for outdoor long-distance free-space optic (FSO) communications. The channel under weak atmospheric turbulence is modeled as a log-normal intensity fading channel where on-off keying makes it look asymmetric. While no effort is made to spectrally match the co...

The Gallager’s random coding error exponent for space-time block codes (STBC) over multiple-input multipleoutput (MIMO) block-fading channels, with Gaussian input distribution, is investigated. Gallager’s error exponent can be used to determine the required codeword length to achieve a prescribed error probability at a given rate below the channel capacity. We first provide new, analytical expr...

Weighted generalizations of Hoffman’s ratio bound on the independence number of a regular graph are surveyed. Several known bounds are reviewed as special cases of modest extensions. Comparisons are made with the Shannon capacity Θ, Lovász’ parameter θ, Schrijver’s parameter θ, and the ultimate independence ratio for categorical products. The survey concludes with some observations on graphs th...

The k-th p-power of a graph G is the graph on the vertex set V (G), where two k-tuples are adjacent iff the number of their coordinates which are adjacent in G is not congruent to 0 modulo p. The clique number of powers of G is poly-logarithmic in the number of vertices, thus graphs with small independence numbers in their p-powers do not contain large homogenous subsets. We provide algebraic u...

We generalise some well-known graph parameters to operator systems by considering their underlying quantum channels. In particular, we introduce the quantum complexity as the dimension of the smallest co-domain Hilbert space a quantum channel requires to realise a given operator system as its non-commutative confusability graph. We describe quantum complexity as a generalised minimum semidefini...