6G • RAN
IRSA
Irregular Repetition Slotted ALOHA with SIC
A packet access protocol where devices transmit random redundant copies across slots, and the receiver uses Successive Interference Cancellation to unravel collisions.
Technical Explanation
Classic slotted ALOHA discards packets whenever collisions occur, capping throughput at 36.8%. Irregular Repetition Slotted ALOHA (IRSA) instructs devices to transmit multiple packet replicas across randomly chosen time slots, with header pointers linking replicas. When the receiver successfully decodes a clean packet in any single slot, it reconstructs its waveform and subtracts its interference from all other collided slots, recursively unraveling massive collision pile-ups.
Key Functions
- Throughput efficiency approaching 90-95% of theoretical channel capacity under collisions
- Recursive Successive Interference Cancellation (SIC) subtracting decoded packet replicas
- Eliminating complex central scheduling and coordination across uncoordinated IoT devices
- Graph-based bipartite decoding algorithms operating with linear computational complexity
- Massive throughput boost for satellite direct-to-cell bursty messaging traffic
Specifications
IEEE Transactions on Communications, 3GPP Rel-19 NTN Machine Type Comms
Interfaces
IRSA-CoreGraph-SIC
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