Adaptive Phase-Shifted Pilot Design for Uplink Multiple Access in ISAC Systems
IEEE Transactions on Wireless Communications, cilt.25, ss.22911-22927, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 25
- Basım Tarihi: 2026
- Doi Numarası: 10.1109/twc.2026.3729634
- Dergi Adı: IEEE Transactions on Wireless Communications
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Compendex, INSPEC, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Sayfa Sayıları: ss.22911-22927
- Anahtar Kelimeler: Adaptive phase-shift, integrated sensing and communication (ISAC), maximum unambiguous range, pilot design, scheduling, uplink multiple access
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- İstanbul Medipol Üniversitesi Adresli: Evet
Özet
Pilot design for uplink multi-transceiver (TRX) integrated sensing and communication (ISAC) systems presents a fundamental trade-off between scheduling capacity and sensing performance. Conventional interleaved or block-based pilots compromise either maximum unambiguous range or range resolution, while phase-shifted-ISAC (PS-ISAC) remains scheduling-capacity-limited by the fixed cyclic prefix (CP) ratio. This paper proposes adaptive phase-shifted-ISAC (APS-ISAC), an overlapping block-pilot structure that assigns each TRX a unique phase shift based on its maximum channel excess delay, allowing multiple TRXs to share the entire time-frequency resource block while keeping their channel impulse responses (CIRs) contiguously packed and separable in the time domain. Our analysis shows that APS-ISAC: 1) schedules approximately twice as many TRXs as baseline methods while reducing per-TRX receiver complexity; 2) achieves a strictly higher achievable rate and slightly lower bit error rate (BER) than interleaved pilots under the per-subcarrier power constraint (PC), supported by a closed-form achievable-rate lower bound under imperfect channel state information (CSI), with both metrics equalizing under the total PC; 3) attains lower range root mean square error (RMSE) under the per-subcarrier PC, an energy-mediated gain that vanishes once total radiated energy is equalized, for both pilot-aided (P-A) and joint pilot-data (J-PD) sensing under orthogonal time-division multiplexed (TDM) data allocation; and 4) simultaneously provides the maximum unambiguous range and the highest possible range resolution. These results establish APS-ISAC as a scalable and ambiguity-resilient pilot design paradigm for next-generation uplink ISAC systems.