A comparison of pilot tone and pilot symbol techniques for digital mobile communication

Both pilot tone and pilot symbol assisted modulation (PTAM and PSAM, respectively) have been proposed for improving transmission performance over flat fading channels. It is shown that there are important practical advantages which favor the pilot symbol technique. PTAM is represented by TTIB (transparent tone-in-band), its most successful version. Bit error rate (BER) performance, the linearization effort required, spectral occupancy, delay, and complexity are considered. On all points but delay, PSAM is superior to PTAM. The strongest contrast is in BER performance, where, for any power amplifier, TTIB is typically 4 dB poorer than PSAM