Fig. 1. Block diagram of the OFDM system used in this study.
Fig. 2. Frame structure of OFDM system.
Fig. 3. Block diagram of the CDMA system used in this study.
Fig. 4. Frame structure of CDMA uplink system.
Fig. 5. Experimental location.
Fig. 6. Experimental environment.
Fig. 7. Transmitting transducers (L) and receiving hyd-rophones (R).
Fig. 8. Transceive systems.
Fig. 9. Performance comparison by pilot spacing when frequency repetition is maximum (a) and time repetition (b) is maximum.
Fig. 10. Performance comparison with maximum excess delay spread and doppler spread when time repetition is fixed.
Fig. 11. Performance comparison by pilot spacing with maximum excess delay spread and doppler spread when frequency repetition is fixed.
Table 1. Parameters of OFDM uplink system.
Table 2. Parameters of CDMA uplink system.
Table 3. Spreading code.
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