Sökning: "adaptive modulation system"
Visar resultat 1 - 5 av 50 avhandlingar innehållade orden adaptive modulation system.
1. Adaptive Modulation and Coding in Wireless Communications with Feedback
Sammanfattning : We study link adaptation techniques which are suitable for the future packet-based wireless communication systems, where in particular, flat Rayleigh fading channels are assumed. Firstly, an adaptive coding scheme based on Rate Compatible Convolutional (RCC) codes is proposed. LÄS MER
2. Adaptation in multiple input multiple output systems with channel state information at transmitter
Sammanfattning : This thesis comprises two parts: the first part presents channel-adaptive techniques to achieve high spectral efficiency in a single user multiple-input multiple-output (MIMO) system; the second part exhibits a programmable and reconfigurable software-defined-radio orkbench(SDR-WB) in the Matlab/Octave environment that accommodates a variety of wireless applications. In an attempt to achieve high spectral efficiency, an adaptive modulation technique is applied at the transmitter to vary the data rate depending on the channel state information (CSI). LÄS MER
3. Channel-Aware Multilevel Coded Modulation for Coherent Fiber-Optic Communications
Sammanfattning : The past decades have shown an ever-increasing demand for high-rate Internet services, motivating a great effort to increase the spectral efficiency of optical networks. In general, fiber-optic links are non-Gaussian, and in contrast to additive white Gaussian noise (AWGN) channels, there is no standard framework for quantifying fundamental limits or designing capacity-approaching coding schemes for such channels. LÄS MER
4. Convolutional Codes for Wireless Packet Data Systems
Sammanfattning : Automatic Repeat reQuest (ARQ) schemes can guarantee an almost error freereception strongly required in data communications. Hybrid type-II ARQschemes are supplied with channel coding to further improve the performance.In these schemes, error correction is performed adaptively which makesthem favorable for applications in time varying channels. LÄS MER
5. Sparse Modeling of Grouped Line Spectra
Sammanfattning : This licentiate thesis focuses on clustered parametric models for estimation of line spectra, when the spectral content of a signal source is assumed to exhibit some form of grouping. Different from previous parametric approaches, which generally require explicit knowledge of the model orders, this thesis exploits sparse modeling, where the orders are implicitly chosen. LÄS MER