{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:TPG5B3IJS2AX2ZPFKRS3WHEMIM","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"16b5a2f8afa0e17f5df8aca2feda53cc6a7b5c7948abf6ba0fa5ac56307dbaac","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2012-06-26T08:39:30Z","title_canon_sha256":"ac161a96f7d50b37d3110c436927c54eac605546f298a388da26986696c92845"},"schema_version":"1.0","source":{"id":"1206.5919","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1206.5919","created_at":"2026-05-18T00:57:56Z"},{"alias_kind":"arxiv_version","alias_value":"1206.5919v3","created_at":"2026-05-18T00:57:56Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1206.5919","created_at":"2026-05-18T00:57:56Z"},{"alias_kind":"pith_short_12","alias_value":"TPG5B3IJS2AX","created_at":"2026-05-18T12:27:23Z"},{"alias_kind":"pith_short_16","alias_value":"TPG5B3IJS2AX2ZPF","created_at":"2026-05-18T12:27:23Z"},{"alias_kind":"pith_short_8","alias_value":"TPG5B3IJ","created_at":"2026-05-18T12:27:23Z"}],"graph_snapshots":[{"event_id":"sha256:96cf7df3e47045272041fb082822fc67f2f1faf8d4ea20ac6cb9505595f77545","target":"graph","created_at":"2026-05-18T00:57:56Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"Kudekar et al. proved that the belief-propagation (BP) performance for low-density parity check (LDPC) codes can be boosted up to the maximum-a-posteriori (MAP) performance by spatial coupling. In this paper, spatial coupling is applied to sparsely-spread code-division multiple-access (CDMA) systems to improve the performance of iterative multiuser detection based on BP. Two iterative receivers based on BP are considered: One receiver is based on exact BP and the other on an approximate BP with Gaussian approximation. The performance of the two BP receivers is evaluated via density evolution (","authors_text":"Keigo Takeuchi, Toshiyuki Tanaka, Tsutomu Kawabata","cross_cats":["math.IT"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2012-06-26T08:39:30Z","title":"Performance Improvement of Iterative Multiuser Detection for Large Sparsely-Spread CDMA Systems by Spatial Coupling"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1206.5919","kind":"arxiv","version":3},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:d34a5fd12e23c371d52dd5609babb6995b019af97648d44fbf33d720b66758dc","target":"record","created_at":"2026-05-18T00:57:56Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"16b5a2f8afa0e17f5df8aca2feda53cc6a7b5c7948abf6ba0fa5ac56307dbaac","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2012-06-26T08:39:30Z","title_canon_sha256":"ac161a96f7d50b37d3110c436927c54eac605546f298a388da26986696c92845"},"schema_version":"1.0","source":{"id":"1206.5919","kind":"arxiv","version":3}},"canonical_sha256":"9bcdd0ed0996817d65e55465bb1c8c4312842125900dead6e87ea0e4e4fcb030","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"9bcdd0ed0996817d65e55465bb1c8c4312842125900dead6e87ea0e4e4fcb030","first_computed_at":"2026-05-18T00:57:56.898239Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:57:56.898239Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"C/HYpTCHAB5wrH62kDbnHNLl6IVAF3Fjl43BUOOaMTUaYANKAZLnYuACEBXi9iMS6BszQH5uMkHng+AdawQuAQ==","signature_status":"signed_v1","signed_at":"2026-05-18T00:57:56.898823Z","signed_message":"canonical_sha256_bytes"},"source_id":"1206.5919","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:d34a5fd12e23c371d52dd5609babb6995b019af97648d44fbf33d720b66758dc","sha256:96cf7df3e47045272041fb082822fc67f2f1faf8d4ea20ac6cb9505595f77545"],"state_sha256":"e6c8bc900b4f5938d67bedc3e20c70b5fff6830e074ecd71431bbf7e85843187"}