In-phase/quadrature (I/Q) imbalances are front-end impairments which may greatly complicate the synchronization task in a low-cost direct-conversion receiver (DCR). In this paper we investigate the possibility of using the space-alternating generalized expectation-maximization (SAGE) algorithm to recover the carrier frequency offset in OFDM terminals with a DCR architecture. Our study leads to a novel scheme that operates in a recursive fashion and exploits a conventional OFDM training preamble composed by several repeated parts. At each iteration, interference arising from I/Q impairments is subtracted from the received samples before updating the frequency estimate. The performance of the new scheme is assessed in terms of estimation accuracy and processing load by considering a wireless local area network (WLAN) compliant with the IEEE 802.11a standard. The main goal is to check whether the SAGE approach exhibits some advantages compared to existing alternatives.
|Autori:||Morelli, Michele; Moretti, Marco|
|Titolo:||A SAGE Approach to Frequency Recovery in OFDM Direct-Conversion Receivers|
|Anno del prodotto:||2014|
|Digital Object Identifier (DOI):||10.1109/LCOMM.2014.012714.140092|
|Appare nelle tipologie:||1.1 Articolo in rivista|