Adaptive OFDM Transmission in TDD Systems with Fixed Minimum Distance of Received Constellations

Conference: European Wireless 2017 - 23th European Wireless Conference
05/17/2017 - 05/19/2017 at Dresden, Germany

Proceedings: European Wireless 2017

Pages: 6Language: englishTyp: PDF

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Sergienko, Alexander B. (Staint Petersburg Electrotechnical University, Staint Petersburg, Russia)

A novel approach for design of time division duplex (TDD) systems with orthogonal frequency division multiplexing (OFDM) and adaptive modulation (AM) is described. The main principle is the use of such power allocation method at the transmitter that ensures equal minimum distances of received modulation constellations for all used subcarriers. This property simplifies modulation classification and improves reliability of modulation parameters estimation. This estimation is based on automatic modulation classification (AMC) according to maximum likelihood (ML) criterion with subsequent correction of the result to constrain the total bit load of OFDM symbol. Simulation results show that the proposed approach gives better performance than the schemes with equal power for all subcarriers and maximum a posteriori probability (MAP)-based modulation classification.