2020–Present · Systems lead
XDD: Cross Division Duplex
Sub-band full duplex for 5G-Advanced and 6G. Extend uplink coverage in TDD by squeezing UL onto a sub-band of the DL slot, and cancel the self-interference that creates.
- Sub-band Full Duplex
- 5G-Advanced
- SIC
- TDD
TDD coverage is uplink-limited at mid-band. The uplink slot is small, the UE is power-constrained, and the path loss doesn’t care. XDD (Cross Division Duplex) is the answer Samsung has been pushing: keep TDD’s spectrum flexibility, but borrow a sub-band of the downlink slot for UL when the base station’s TX would otherwise be deafening it.
That sub-band coexistence only works if you can cancel the BS’s own DL leakage into its UL receiver. The receiver-side cancellation R&D that makes XDD practical is documented across a separate body of equalizer-based work — see MIMO Self-Interference Cancellation.
Selected publications
- Extending 5G TDD Coverage with XDD: Cross Division Duplex — IEEE Access (2021). Journal paper showing XDD can improve UL coverage up to 2.37× over TDD, with a PoC validating the SIC techniques.
- XDD: Cross Division Duplex in 5G-Advanced — IEEE VTC2021-Fall. Conference introduction of the 5G-Advanced XDD scheme.
- Enabling Advanced Duplex in 6G — IEEE ICC Workshops 2021. The 6G-facing framing of advanced duplexing techniques.
- 5G-Advanced Duplex Evolution for Massive MIMO and Multi-Beam Operations — IEEE WCNC 2023. Bringing XDD into massive-MIMO and multi-beam operation regimes.