Transmission of information by orthogonal functions

Dynamic Space-Code Multiple Access (DSCMA) System: A Double Interference Cancellation Multiple Access Scheme in Wireless Communications System

“…Traditional CDMA spreading sequences such as m-sequence (Golomb, 1992), Gold codes (Gold, 1967), and Kasami codes (Kasami, 1966), exhibit non-zero cross-correlation which results in high MAI in asynchronous reverse link transmission. Another family of orthogonal codes is constituted by Walsh codes (Harmuth, 1970) and orthogonal Gold codes (Popovic, 1997), do retain their orthogonality in the case of perfect synchronization, but also exhibit non-zero cross-correlation in asynchronous transmission (Wei et al, 2005). Recently, an attractive family of large area synchronized (LAS) CDMA spreading sequences is introduced in (Li, 2003) has exhibited zero correlation zone (ZCZ) or interference free window (IFW) near zero delay time offset, resulting in zero ISI and MAI within the IFW.…”

Symmetropy, an entropy-like measure of visual symmetry

“…Every function f(x) which is integrable in the Lebesgue sense can be expressed in the interval 0 .. x < 1 as a series of the form Some Fundamental Properties We now present without proof some fundamental properties of Walsh functions that will be needed in the paper. (For detailed explanations, refer to Beauchamp, 1975, andHarmuth, 1972. ) Multiplication.…”

“…There are several different ways of defining and/or representing Walsh functions (Beauchamp, 1975;Harmuth, 1972). In this paper, we adopt the definition shown below (Blachman, 1974) derived from sinusoidal functions, because, although most readers will be unfamiliar with Walsh functions, they will be familiar with Fourier (sine-cosine) functions.…”

Theory and Applications of Generalized Walsh Functions in Digital Systems.

“…Raster scanning makes the first element of t he second number ~~s tem are inherently relevant in ~h e processing of m x m row (which is spatially close to the first element of the first ro~) matrix signals Ahmed et al [3] discussed the generation of a the (m + I)th element. Conversely, the reconstruction of an image famil y of discrete orthogonal transforms for a given periodic dat a from a one-dimensional digital signal puts the (m I )th element sequence Their emp hasis was in factoring these transfo rm at the head of the second row which is close to the firs t elemenl of matrices into a product of sparse mat rices and was not concerned the first row.…”