An AFDM-Based Integrated Sensing and Communications

Affine Frequency Division Multiplexing for Next-Generation Wireless Networks

“…We now show that the assumption h 0 = 0 we made following (3) is justifiable when sensing is performed using only the AFDM pilot signal i.e., y p , because in that case SIC can be achieved with simple analog dechirping and filtering. This is a major advantage over the AFDM-based ISAC in [9] and OFDM-and OTFS-based ISAC which all need costly fullduplex SIC solutions. It also has a significant advantage over OCDM-based ISAC, as we show below.…”

“…This makes AFDM a potential candidate waveform for ISAC [8]. A first AFDM-based ISAC scheme with a sensing approach that uses the full AFDM signal (both its data and pilot parts) is proposed in [9], showing very good sensing performance even in large Doppler scenarios, however only under the restrictive assumption of target ranges corresponding to integer-valued delays.…”

“…In this letter, we propose a novel ISAC scheme leveraging AFDM and we analyze its performance under both fractional delay and Doppler shifts, i.e., without requiring the restrictive integer-delays assumption of [9]. We show that sensing in AFDM-based ISAC can be done using either the whole frame as in [9], or one pilot symbol, motivated from [5] in which as few as one DAFT domain symbol used as a pilot can yieldwhen appended with a sufficient number of zero guard samples -the possibility to identify all the delay and Doppler components associated with the propagation medium.…”

“…In this letter, we propose a novel ISAC scheme leveraging AFDM and we analyze its performance under both fractional delay and Doppler shifts, i.e., without requiring the restrictive integer-delays assumption of [9]. We show that sensing in AFDM-based ISAC can be done using either the whole frame as in [9], or one pilot symbol, motivated from [5] in which as few as one DAFT domain symbol used as a pilot can yieldwhen appended with a sufficient number of zero guard samples -the possibility to identify all the delay and Doppler components associated with the propagation medium. Evidently, this is relevant for sensing and radar applications since the delay-Doppler representation of the wireless channel associated with the round-trip propagation from the wireless transmitter to the targets in its vicinity and back to the transmitter translates into range-velocity information about those targets.…”