Frequency synchronization and channel equalization for an OFDM-IDMA uplink system

Hector Poveda (1) , Guillaume Ferré (1) , Eric Grivel (1)

1 IMS - Laboratoire de l'intégration, du matériau au système

This paper deals with a system combining orthogonal frequency di- vision multiplexing (OFDM) and interleave-division multiple access (IDMA). OFDM makes the system robust against intersymbol inter- ference, whereas IDMA combats the multiple access interference. Nevertheless, unwanted phenomena must be taken into account: 1/ carrier frequency offset (CFO) must be estimated/corrected to guarantee the orthogonality between subcarriers and hence the sym- bol detection in the system. 2/ the conventional iterative IDMA receiver, initially proposed by Ping et al., requires a priori knowl- edge of the multipath channel. Therefore, the CFO and the multipath channel must be estimated "accurately" in an OFDM-IDMA system. Our contribution is to propose a new scheme where a CFO correc- tion is no longer necessary, unlike common OFDM approaches. We show that without a CFO correction, the symbols transmitted by the different users can be recovered by modifying the conventional iterative architecture of the IDMA receiver. When considering an OFDM-IDMA network over different Rayleigh fading channels, simulation results clearly show the efficiency of the proposed algorithm in terms of estimation accuracy and bit error rate.

Mots clés: OFDM-IDMA; CFO/channel correction; CFO/ channel estimation; sigma-points Kalman filter

Domaines: Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Hector Poveda, Guillaume Ferré, Eric Grivel. Frequency synchronization and channel equalization for an OFDM-IDMA uplink system. Icassp 2012, Mar 2012, Kyoto, Japan. pp.1-5. ⟨hal-00670062⟩