{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:NK6YJKG5UVMI6HTGWTKTUOD4J7","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":"a0af45b83d5de86507a8219f9eb5f0f99fbcf600308d8bff852c967527338362","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2018-09-11T08:55:51Z","title_canon_sha256":"2ffce7ab4f1dc2541f0b99db9f04d27b55f22a40038ee4966ec61112dbd3fdaa"},"schema_version":"1.0","source":{"id":"1809.03751","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1809.03751","created_at":"2026-05-18T00:05:59Z"},{"alias_kind":"arxiv_version","alias_value":"1809.03751v1","created_at":"2026-05-18T00:05:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1809.03751","created_at":"2026-05-18T00:05:59Z"},{"alias_kind":"pith_short_12","alias_value":"NK6YJKG5UVMI","created_at":"2026-05-18T12:32:40Z"},{"alias_kind":"pith_short_16","alias_value":"NK6YJKG5UVMI6HTG","created_at":"2026-05-18T12:32:40Z"},{"alias_kind":"pith_short_8","alias_value":"NK6YJKG5","created_at":"2026-05-18T12:32:40Z"}],"graph_snapshots":[{"event_id":"sha256:39075a8612aa919a795766dea6b7748a9ea004a9c3b1338950e6b0524952abee","target":"graph","created_at":"2026-05-18T00:05:59Z","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":"We propose a downlink beamforming scheme that combines spatial division and orthogonal space-time block coding (OSTBC) in multi-user massive MIMO systems. The beamformer is divided into two parts: a pre-beamforming matrix to separate the users into different beams with no interference between each other, which is designed based on the low rank covariance matrix of the downlink channel, and a linear precoding matrix using partial or even no channel state information (CSI) concatenated by an OSTBC. To construct the pre-beamforming matrix, a simple method that selects columns from DFT matrix is p","authors_text":"Hui-Ming Wang, Jia Hou, Ke-Wen Huang, Shi Jin","cross_cats":["math.IT"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2018-09-11T08:55:51Z","title":"Joint Spatial Division and Diversity for Massive MIMO Systems"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1809.03751","kind":"arxiv","version":1},"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:ec24865e6c737fbd5e9709e3c6af5d69435c784f3092cd9d9d316c14bc62782c","target":"record","created_at":"2026-05-18T00:05:59Z","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":"a0af45b83d5de86507a8219f9eb5f0f99fbcf600308d8bff852c967527338362","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2018-09-11T08:55:51Z","title_canon_sha256":"2ffce7ab4f1dc2541f0b99db9f04d27b55f22a40038ee4966ec61112dbd3fdaa"},"schema_version":"1.0","source":{"id":"1809.03751","kind":"arxiv","version":1}},"canonical_sha256":"6abd84a8dda5588f1e66b4d53a387c4fdbb0370f5d084b6930687d9cca7263af","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"6abd84a8dda5588f1e66b4d53a387c4fdbb0370f5d084b6930687d9cca7263af","first_computed_at":"2026-05-18T00:05:59.943184Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:05:59.943184Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"aVUMRAUqVhgXA+2Gx3MK4DPHraSpbpnQoTjukqcHZ02COtvuysidfDod5budylVDffyEr4too40dRkDQqP68Dg==","signature_status":"signed_v1","signed_at":"2026-05-18T00:05:59.943829Z","signed_message":"canonical_sha256_bytes"},"source_id":"1809.03751","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:ec24865e6c737fbd5e9709e3c6af5d69435c784f3092cd9d9d316c14bc62782c","sha256:39075a8612aa919a795766dea6b7748a9ea004a9c3b1338950e6b0524952abee"],"state_sha256":"092e56f603bc5c3255e5023f9a45bed17806c873b3c9f6b27517f7585b28767a"}