2,281 research outputs found
Impact of channel-state information on coded transmission over fading channels with diversity reception
No full textBrowse Journals & Magazines > Communications, IEEE Transact ...> Volume:47 Issue:9 Prev | Back to Results | Next » Impact of channel-state information on coded transmission over fading channels with diversity reception .This paper appears in: Communications, IEEE Transactions on Date of Publication: Sep 1999 Author(s): Taricco, Giorgio Dipt. di Elettronica, Politecnico di Torino, Italy Biglieri, Ezio M.; Caire, Giuseppe Volume: 47 , Issue: 9 Page(s): 1284 - 1287 Product Type: Journals & Magazines 1 1 789660 searchabstract .Abstract We study the synergy between coded modulation and antenna-diversity reception on channels affected by slow Rician fading. Specifically, we assess the impact of channel-state information (CSI) on error probability. We show that with a good coding and constant envelope modulations (for example, phase-shift keying) scheme the loss in performance when CSI is not available is moderate (around 1.5 dB). Moreover, as the diversity order grows, the channel tends to become Gaussia
On the Convergence of Multipath Fading Channel Gains to the Rayleigh Distribution
Full text linkThe gain of a multipath propagation scenario is addressed by this work and it is shown that the convergence to the Rayleigh distribution depends on some conditions on the path gains, which are not always satisfied. These conditions confirm the convergence to the Rayleigh distribution for some well known scenarios. However, counter-examples are also exhibited where this convergence does not hold. Furthermore, the role of the Central Limit Theorem (often advocated in the literature to prove convergence to the Rayleigh distribution) is critically discussed by showing that the Lindeberg condition may not hold. Finally, it is shown that the amplitude and phase of the asymptotic gain are independent and the phase is uniformly distributed over [0, 2π
Asymptotic error performance of space-time codes over fully correlated Rician fading MIMOchannels with imperfect CSI
No full textFair Power Allocation Policies for Power-Domain Non-Orthogonal Multiple Access Transmission With Complete or Limited Successive Interference Cancellation
Full text linkPower-Domain Non-Orthogonal Multiple Access (NOMA) transmission has been addressed in this paper with a proportional fairness optimization criterion (which includes MAX-MIN fairness as a special case) and an arbitrary number of users. The optimization of the power allocation coefficients required to achieve the optimum proportional fairness objective leads to a nonconvex optimization problem, which is generally hard to solve and may lead to multiple local optima. However, a simple optimality condition is characterized in the paper, leading to the solution of a nonlinear equation in a single variable. This equation reduces to polynomial form in the case of MAX-MIN fairness. Departing from the complete Successive Interference Cancellation (SIC) paradigm, typical of NOMA systems, a limited SIC technique is discussed and the relevant power allocation coefficients are obtained with the same optimization criterion. This approach eases the implementation of downlink NOMA when a large number of low-complexity hand-held terminals cannot sustain the computationally intensive task of complete SIC, at the cost of reduced their achievable rates. Numerical results are presented to illustrate the impact of complete and limited SIC, with power allocation optimization and two proportional fairness criteria. Among these results, the sum-rate loss due to proportional fairness and the impact of limited SIC on the system performance are illustrated
Optimum receiver design and performance analysis for fully correlated Rician fading MIMO channels with imperfect channel state information
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Robust Detection Analysis of Linear Cooperative Spectrum Sensing for Cognitive Radio Networks
No full textImpact of imperfect channel state information on the performance of wireless sensor networks2012 IEEE Global Communications Conference (GLOBECOM)
No full textThe performance of wireless sensor networks (WSN) is often assessed without paying close attention to the effects of channel state information recovery, which is assumed to be exactly known. This work focuses on the effects of imperfect knowledge of the channel state information on a WSN whose sensors measure a target parameter and send it to a common fusion center by an amplify-and-forward technique. A baseline estimation rule, consisting in disregarding the presence of noise in the estimated channel gain, is considered. Two other estimation rules are also studied, based on the joint processing of the received samples during the sensing and training intervals: i) a maximum a posteriori rule consisting in maximizing the a posteriori probability of the target parameter; ii) a least-squares rule based on the minimization of the mean-square error of the estimated target parameter. In both cases, conditionally on the target parameter, the received samples are assumed to be jointly Gaussian distributed as far as concerns the derivation of the estimation rule. Numerical results illustrate the merits of the proposed estimation rules by showing the MSE performance with different network parameters
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