2 research outputs found
Frequency offset estimation for IFDMA uplink systems
This paper proposes two frequency offset estimation algorithms for
the uplink of an Interleaved Frequency-Division Multiple-Access
(IFDMA) system. One algorithm performs estimation in the frequency
domain and the other in the time domain. Both algorithms are
based on the maximum likelihood estimation (MLE) principle and use
knowledge about pilot symbols. IFDMA utilizes a block-interleaved
frequency allocation scheme to exploit the frequency diversity of
the channel. In the presence of frequency offsets between users,
multiple-access interference (MAI) appears, which has a negative
impact on existing frequency offset estimation algorithms. The
proposed algorithms are robust, since a special construction of
pilot symbols allows to exclude a large amount of MAI in the
presence of frequency offsets between users. As a result, the
proposed time domain frequency estimation algorithm outperforms
the frequency domain algorithm and all other known schemes