eprintid: 1761 rev_number: 9 eprint_status: archive userid: 12 dir: disk0/00/00/17/61 datestamp: 2016-05-30 05:21:45 lastmod: 2016-05-30 05:21:45 status_changed: 2016-05-30 05:21:45 type: article metadata_visibility: show creators_name: Nguyen, Cong Luong creators_name: Mokraoui, Anissa creators_name: Duhamel, Pierre creators_name: Nguyen, Linh Trung creators_id: luong.nguyen@univ-paris13.fr creators_id: anissa.mokraoui@univ-paris13.fr creators_id: pierre.duhamel@lss.supelec.fr creators_id: linhtrung@vnu.edu.vn title: Improved time and frequency synchronization in presence of imperfect channel state information ispublished: pub subjects: Communications subjects: ECE subjects: isi divisions: fac_fet abstract: This paper addresses altogether time and frequency synchronization in IEEE 802.11a orthogonal frequency division multiplexing (OFDM) wireless communication systems. The proposed algorithms have two main features: (i) they make use of an additional source of information available at IEEE 802.11a physical layer, on top of the usual ones typically adopted for synchronization such as training sequences. This additional source of information is provided by the higher layers of the communication protocol. In fact, when the carrier sense multiple access with collision avoidance (CSMA/CA) protocol is activated, the receiver is able to predict some parts of the SIGNAL field that are classically assumed unknown. Moreover, during the negotiation of the transmission medium reservation, the exchanged frames not only help the receiver to predict the SIGNAL field but also to obtain information about the channel state. (ii) Based on this property, we propose a joint MAP time and frequency synchronization algorithm using all available information. Finally, the time synchronization is fine tuned by means of a specific metric in the frequency domain that allows us to minimize the expectation of the transmission error function over all channel estimate errors. Simulation results compliant with the IEEE 802.11a standard in both indoor and outdoor environments show that the proposed algorithm drastically improves the performance in terms of synchronization failure probability and bit error ratio, compared to state-of-the-art algorithms. date: 2015 date_type: published publisher: Springer official_url: http://link.springer.com/journal/13638 full_text_status: public publication: EURASIP Journal on Wireless Communications and Networking volume: 2015 number: 1 pagerange: 1-17 refereed: TRUE issn: 1687-1499 citation: Nguyen, Cong Luong and Mokraoui, Anissa and Duhamel, Pierre and Nguyen, Linh Trung (2015) Improved time and frequency synchronization in presence of imperfect channel state information. EURASIP Journal on Wireless Communications and Networking, 2015 (1). pp. 1-17. ISSN 1687-1499 document_url: https://eprints.uet.vnu.edu.vn/eprints/id/eprint/1761/1/55fbf37508ae07629e07c959.pdf