Low Density Spreading Multiple Access
نویسندگان
چکیده
منابع مشابه
Analysis of Finite Field Spreading for Multiple-Access Channel
Finite field spreading scheme is proposed for a synchronous multiple-access channel with Gaussian noise and equal-power users. For each user, s information bits are spread jointly into a length-sL vector by L multiplications on GF(2s). Thus, each information bit is dispersed into sL transmitted symbols, and the finite field despreading (FF-DES) of each bit can take advantage of sL independent r...
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The letter presents a theoretical analysis on a performance index for chaotic spreading sequences, which characterizes the multiple access interference introduced by crosscorrelation of a sequence set in asynchronous DS/CDMA systems. Using the ergodic theory, is expressed in terms of ensemble-averaged autocorrelation functions and simple explicit formulae for are obtained, under the assumption ...
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In this paper, we analyze the error performance of an ultra-wideband (UWB) system with pulse position modulation (PPM) for data modulation and direct sequence (DS) spreading for multiple access in indoor lognormal fading channels. A RAKE receiver is used to combine a subset of the resolvable multipath components using the maximal ratio combining technique. Inter-path and multiple-access interfe...
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The problem of estimating the propagation delay of a new user in a (coded) DS/CDMA system in the presence of multiple access interference (MAI) is considered. MAI resistant acquisition schemes are developed for a general CDMA system without the constraint that the spreading sequences of the users repeat every symbol period. It is assumed that the spreading sequences and delays of the interferin...
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Served as one of the most widely used wireless air link interfaces, code division multiple access (CDMA) has been identified as a major technique for 3G wireless communications. Here, a new method based on applying encryption algorithm over spreading codes is proposed to improve the security of CDMA. The security produced in this way is primarily associated with the complexity of the employed e...
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ژورنال
عنوان ژورنال: Journal of Information Technology & Software Engineering
سال: 2012
ISSN: 2165-7866
DOI: 10.4172/2165-7866.1000e108