Performance evaluation of time-multiplexed and data-dependent superimposed training based transmission with practical power amplifier model

Abstract

The increase in the peak-to-average power ratio (PAPR) is a well known but not sufficiently addressed problem with data-dependent superimposed training (DDST) based approaches for channel estimation and synchronization in digital communication links. In this article, we concentrate on the PAPR analysis with DDST and on the spectral regrowth with a nonlinear amplifier. In addition, a novel Gaussian distribution model based on the multinomial distribution for the cyclic mean component is presented. We propose the use of a symbol level amplitude limiter in the transmitter together with a modified channel estimator and iterative data bit estimator in the receiver. We show that this setup efficiently reduces the regrowth with the DDST. In the end, spectral efficiency comparison between time domain multiplexed training and DDST with or without symbol level limiter is provided. The results indicate improved performance for DDST based approaches with relaxed transmitter power amplifier requirements.

Archives of Acoustics

“…where P n is the distortion limited output power and Z is the rated load impedance for which the output power is specified. The Rapp model (Rapp, 1991) commonly used to model solid state RF amplifiers (Levanen et al, 2012) was also verified. This model is described by Eq.…”

Iterative MIMO Detection and Channel Estimation Using Joint Superimposed and Pilot-Aided Training

“…The MSE of the ST case can be found in [11]. It may be inferred from (27) thatB represents an extra term for the channel estimate. This time-average term is exploited by the following method.…”

“…It is important to stress that the termB will be nonexistent at the receiver end, because it was removed at the transmitter side when the signal E was added. Hence, using (25) and (27), the LS time-domain channel estimator based on the synchronized averaging of the received signal R is given bŷ…”

“…This is an important issue, because recent communication standards consider this type of modulation; for example, WiMAX (IEEE 802.16e-2005 standard) uses 64-QAM digital modulation that DDST cannot support. In addition, DDST presents two more drawbacks: its performance is highly sensitive to the data block length used as well as the increased peak-power and peak-to-average ratio (PAPR) in the transmitted signal, as shown in [27].…”