On the Study of Frequency Offset Estimation for OFDMA Uplink Systems

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details


This research project proposes a low-complexity-and-high-precision solution of the frequency synchronization problem in the orthogonal frequency division multiple access (OFDMA) uplink system using interleaved or subband carrier assignment strategies (CAS). This study first investigates the Vandermonde property of the signals sampled at specific time instances in the OFDMA using the interleaved CAS, and then uses these time samples to construct multiple snapshot vectors in a single OFDMA symbol. These snapshot vectors can be expressed as a linear combination of carrier frequency offset (CFO) signature vectors of the active users. This study intends to design a series of notch filters to null out the CFO signatures, and then uses a polynomial-rooting method to estimate the CFOs from the characteristic function of the notch filter. To obtain the associated filter coefficients, we seek to find three different solutions based on various design criteria: 1) constrained least square (Constrained-LS) method, 2) eigen filter method, and 3) adaptive filtering method. In addition to applying the above methods to the OFDMA with interleaved CAS, this study will explore the frequency synchronization issue for the system with subband CAS as well.

Project IDs

Project ID:PB10408-5694
External Project ID:MOST104-2221-E182-010
Effective start/end date01/08/1531/07/16


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