No abstract

We use the statistical properties of a frequency selective single-input multiple-output channel to predict the distribution of the signal-to-interference-and-noise ratio (SINR) at the output of an iterative equalizer. The SINR distribution is then used to derive the distribution of the variance of the soft demapped bit log likelihood ratios (LLRs). Extrinsic information transfer (EXIT) charts establish a relationship between the LLR variance and mutual information. Thus, by comparing the semi-analytically calculated LLR variance distribution at the demapper output to a previously measured EXIT chart of a turbo decoder, we can reliably estimate the expected frame error ratio. This prediction method is extended for the Chase combining hybrid automatic repeat-request protocol.

This paper proposes a semianalytical performance prediction method for an iterative receiver that processes signals arriving through a frequency-selective multiple-input multipleoutput radio channel. Earlier results provide a distribution of the signal-to-interference-plus-noise ratio at the output of a frequency domain soft interference cancellation minimum mean square error equalizer, which is used to approximate the distribution of the log-likelihood ratios (LLRs) of the demapped bits. Mutual information transfer charts establish a bijective relationship between the variance of the LLRs and the mutual information. We assume a 3rd Generation Partnership Project compliant turbo code, whose transfer charts are simulated in advance. By approximating the LLR variance distribution of the demapped equalizer output, we can evaluate the probability of an intersection between an equalizer chart associated with a random channel realization and a fixed decoder chart. This probability provides the frame error rate. Our proposed prediction method allows horizontally and vertically encoded spatial multiplexing schemes. The vertically encoded scheme is complemented by the inclusion of the Chase combining hybrid automatic repeat request protocol. The proposed method allows reasonable receive antenna correlation.Index Terms-Extrinsic information transfer (EXIT) chart analysis, frequency-domain equalization, iterative processing, minimum mean square error, multiple-input multiple-output (MIMO) channels.

No abstract

Abstrakti Kevään 2013 Kemian opetuksen keskeiset alueet II -kurssin opiskelijat perehtyivät keskeisten kemian käsitteiden historiaan ja tutkimustietoon historian käytöstä kemian opetuksessa.Kirjallisuuteen perehtymisen pohjalta he kehittivät materiaalia kemian opetukseen yläkoulussa ja lukiossa. Materiaaleissa historiallista lähestymistapaa käytetään kemian käsitteiden ja ilmiöiden opettamisen lisäksi myös käsittelemään kemian luonnetta luonnontieteenä. Alla olevissa artikkeleissa opiskelijat esittävät teoreettista taustaa historialliselle lähestymistavalle ja esittelevät kehittämäänsä materiaaliin liittyvää historiaa. Valmiit opetusmateriaalit löytyvät Kemian opetuksen keskuksen KEMMA:n sivuilta osoitteesta http://www.luma.fi/kemma.