14 research outputs found

    On the Outage Theorem and its Converse for Discrete Memoryless Channels

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    Journal PaperWe prove both the outage theorem and its converse for block fading discrete memoryless channel. If <i>P<sub>out</sub></i> is the outage probability for the rate <i>R</i> then any transmission rate below <i>R</i> together with any average error probability greater than <i>P<sub>out</sub></i> is achievable. Conversely, for any code with rate slightly greater than <i>R</i> the error probability is greater than any number smaller than <i>P<sub>out</sub></i>, for large codeword lengths. Two cases are considered depending on whether the transmitter has channel state information (CSI) or not.Noki

    An Approach to Capacity Analysis of Coarsely Coordinated Low Power Multiple Access Systems

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    Conference paperWe consider multiaccess problem in low power systems, where we allow each user to select its own data rate and transmit power locally and independently from other users. Here, every user has a set of low power codebooks, labeled a <i>policy</i>, which accomodates a range of small spectral efficiencies, while treating instantaneous data rates of other users as an unknown compound parameter. Even with such coarse user coordination, multiuser detection enables a system which is superior to any classic orthogonal division system. First we fully characterise the set of achievable policies, after which we demonstrate that in multiantenna systems, policies are be viewed as awarding protected receiver spatial dimensions to each user.Noki

    Hybrid Linear-Iterative Detection Algorithms for MIMO CDMA

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    Conference PaperWe assume a CDMA downlink multiuser scenario, where the base station is equipped with multiple transmit antennas, and each user has multiple receive antennas. For this setup we propose a new, computationally effective MIMO multiuser detector for frequency selective channels. We exploit the fact that the interference mainly comes from the spatial domain, while the residual interference is due to temporal dispersion and multiuser interference. This motivates us to suppress the residual interference in a linear fashion, while combating the spatial interference iteratively. This approach is an efficient performance-complexity tradeoff between full iterative and linear detectors