{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2023,8,27]],"date-time":"2023-08-27T10:54:36Z","timestamp":1693133676207},"reference-count":0,"publisher":"Acoustical Society of America (ASA)","issue":"5_Supplement","content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2008,5,1]]},"abstract":"<jats:p>OFDM communication has recently been demonstrated in underwater channels at rates exceeding 7 kbps. This is a popular modulation in wireless communications due to its flexibility for spectrum management and the simplicity of transmitters\/receivers. Despite widespread interest, experimental data on the performance of underwater OFDM are scarce. This work aims to contribute to a better understanding of this technique by examining results from the UAB'07 experiment, conducted in Norway in September 2007. Data were transmitted in a fjord using several formats with bandwidths of 3 and 7.5 kHz, and recorded at a range of 800 m in a 16-hydrophone array. Significant multipath was observed over at least 40 ms, which would call for a rather large OFDM prefix\/guard interval and hence drastically reduce the data rate. Passive time reversal is used here as a computationally inexpensive scheme to shorten the channel length to less than 10 ms, so that moderate guard intervals can be used with a conventional OFDM receiver. The same preamble\/postamble signals used for synchronization and Doppler precompensation are reused as probes for passive time reversal, so the latter entails no loss in efficiency. The performance of time-reversed OFDM is compared with plain QPSK modulation using either time reversal or multichannel equalization at the receiver.<\/jats:p>","DOI":"10.1121\/1.2935841","type":"journal-article","created":{"date-parts":[[2008,5,12]],"date-time":"2008-05-12T15:14:03Z","timestamp":1210605243000},"page":"3891-3891","update-policy":"http:\/\/dx.doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":9,"title":["Experimental assessment of time-reversed OFDM underwater communications"],"prefix":"10.1121","volume":"123","author":[{"given":"Joao","family":"Gomes","sequence":"first","affiliation":[{"name":"ISR - Instituto Superior Tecnico, Av. Rovisco Pais, Torre Norte 7.22, 1049-001 Lisboa, Portugal, jpg@isr.ist.utl.pt"}]},{"given":"Antonio","family":"Silva","sequence":"additional","affiliation":[{"name":"ISR, Universidade do Algarve, PT-8005-139 Faro, Portugal, asilva@ualg.pt"}]},{"given":"Sergio","family":"Jesus","sequence":"additional","affiliation":[{"name":"ISR, Universidade do Algarve, PT-8005-139 Faro, Portugal, sjesus@ualg.pt"}]}],"member":"231","container-title":["The Journal of the Acoustical Society of America"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.aip.org\/jasa\/article\/123\/5_Supplement\/3891\/650087\/Experimental-assessment-of-time-reversed-OFDM","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.aip.org\/jasa\/article\/123\/5_Supplement\/3891\/650087\/Experimental-assessment-of-time-reversed-OFDM","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,7,19]],"date-time":"2023-07-19T12:47:27Z","timestamp":1689770847000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.aip.org\/jasa\/article\/123\/5_Supplement\/3891\/650087\/Experimental-assessment-of-time-reversed-OFDM"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,5,1]]},"references-count":0,"journal-issue":{"issue":"5_Supplement","published-print":{"date-parts":[[2008,5,1]]}},"URL":"https:\/\/doi.org\/10.1121\/1.2935841","relation":{},"ISSN":["0001-4966","1520-8524"],"issn-type":[{"value":"0001-4966","type":"print"},{"value":"1520-8524","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2008,5]]},"published":{"date-parts":[[2008,5,1]]}}}