{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:YG32PIRKSNDSWKYDAEHKBCWL76","short_pith_number":"pith:YG32PIRK","canonical_record":{"source":{"id":"1904.07515","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2019-04-16T07:52:42Z","cross_cats_sorted":[],"title_canon_sha256":"d9081e76c64458c6d55610056501dae815ee13d560c16fca9bdd4b8e3f4e18bd","abstract_canon_sha256":"d7a86bc8130a72755d91f78fb789ac8e7d34533dd04c7f1187d6e8718c13e544"},"schema_version":"1.0"},"canonical_sha256":"c1b7a7a22a93472b2b03010ea08acbff9f1ebd5a67a2210497f03adc605830cb","source":{"kind":"arxiv","id":"1904.07515","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1904.07515","created_at":"2026-05-17T23:48:25Z"},{"alias_kind":"arxiv_version","alias_value":"1904.07515v1","created_at":"2026-05-17T23:48:25Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1904.07515","created_at":"2026-05-17T23:48:25Z"},{"alias_kind":"pith_short_12","alias_value":"YG32PIRKSNDS","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_16","alias_value":"YG32PIRKSNDSWKYD","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_8","alias_value":"YG32PIRK","created_at":"2026-05-18T12:33:33Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:YG32PIRKSNDSWKYDAEHKBCWL76","target":"record","payload":{"canonical_record":{"source":{"id":"1904.07515","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2019-04-16T07:52:42Z","cross_cats_sorted":[],"title_canon_sha256":"d9081e76c64458c6d55610056501dae815ee13d560c16fca9bdd4b8e3f4e18bd","abstract_canon_sha256":"d7a86bc8130a72755d91f78fb789ac8e7d34533dd04c7f1187d6e8718c13e544"},"schema_version":"1.0"},"canonical_sha256":"c1b7a7a22a93472b2b03010ea08acbff9f1ebd5a67a2210497f03adc605830cb","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:48:25.016629Z","signature_b64":"/n7mzezh6537CCE8M8v7f72yywiwDFevaSomrCFLGL6kBcihmoW2nOzO7tdeumd9zQWf1mF1e0Urzn66DewRBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"c1b7a7a22a93472b2b03010ea08acbff9f1ebd5a67a2210497f03adc605830cb","last_reissued_at":"2026-05-17T23:48:25.016100Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:48:25.016100Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1904.07515","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-17T23:48:25Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"eY03eWU97Nxk15czr2qR3rRje6sUEBoje50uKFMtuMbRdjyPo6B9BrYwDrw6JxAeIf2pOwXpua1UriYpvG2WCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-04T15:25:40.142805Z"},"content_sha256":"876341087127cd454938130a6dbd19d60a7e1e9c43398ca46b7989b4e7dff0b2","schema_version":"1.0","event_id":"sha256:876341087127cd454938130a6dbd19d60a7e1e9c43398ca46b7989b4e7dff0b2"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:YG32PIRKSNDSWKYDAEHKBCWL76","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Sparse Subspace Decomposition for Millimeter Wave MIMO Channel Estimation","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"eess.SP","authors_text":"David J. Love, Taejoon Kim, Wei Zhang","submitted_at":"2019-04-16T07:52:42Z","abstract_excerpt":"Millimeter wave multiple-input multiple-output (MIMO) communication systems must operate over sparse wireless links and will require large antenna arrays to provide high throughput. To achieve sufficient array gains, these systems must learn and adapt to the channel state conditions. However, conventional MIMO channel estimation can not be directly extended to millimeter wave due to the constraints on cost-effective millimeter wave operation imposed on the number of available RF chains. Sparse subspace scanning techniques that search for the best subspace sample from the sounded subspace sampl"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.07515","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-17T23:48:25Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"pRzEWAvtrJoNvxmUQ8yhDxy1LBsM9IBWFURcum84+Req00Xe1DFJKMcqjvd3OlLt+Hv/y6BacYWu3sWBlYx1BQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-04T15:25:40.143211Z"},"content_sha256":"0170852946662d95514256ed9ddf5ca083291a9f1bd3b8c85eaf48deddcfe1b5","schema_version":"1.0","event_id":"sha256:0170852946662d95514256ed9ddf5ca083291a9f1bd3b8c85eaf48deddcfe1b5"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/YG32PIRKSNDSWKYDAEHKBCWL76/bundle.json","state_url":"https://pith.science/pith/YG32PIRKSNDSWKYDAEHKBCWL76/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/YG32PIRKSNDSWKYDAEHKBCWL76/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-04T15:25:40Z","links":{"resolver":"https://pith.science/pith/YG32PIRKSNDSWKYDAEHKBCWL76","bundle":"https://pith.science/pith/YG32PIRKSNDSWKYDAEHKBCWL76/bundle.json","state":"https://pith.science/pith/YG32PIRKSNDSWKYDAEHKBCWL76/state.json","well_known_bundle":"https://pith.science/.well-known/pith/YG32PIRKSNDSWKYDAEHKBCWL76/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:YG32PIRKSNDSWKYDAEHKBCWL76","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":"d7a86bc8130a72755d91f78fb789ac8e7d34533dd04c7f1187d6e8718c13e544","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2019-04-16T07:52:42Z","title_canon_sha256":"d9081e76c64458c6d55610056501dae815ee13d560c16fca9bdd4b8e3f4e18bd"},"schema_version":"1.0","source":{"id":"1904.07515","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1904.07515","created_at":"2026-05-17T23:48:25Z"},{"alias_kind":"arxiv_version","alias_value":"1904.07515v1","created_at":"2026-05-17T23:48:25Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1904.07515","created_at":"2026-05-17T23:48:25Z"},{"alias_kind":"pith_short_12","alias_value":"YG32PIRKSNDS","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_16","alias_value":"YG32PIRKSNDSWKYD","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_8","alias_value":"YG32PIRK","created_at":"2026-05-18T12:33:33Z"}],"graph_snapshots":[{"event_id":"sha256:0170852946662d95514256ed9ddf5ca083291a9f1bd3b8c85eaf48deddcfe1b5","target":"graph","created_at":"2026-05-17T23:48:25Z","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":"Millimeter wave multiple-input multiple-output (MIMO) communication systems must operate over sparse wireless links and will require large antenna arrays to provide high throughput. To achieve sufficient array gains, these systems must learn and adapt to the channel state conditions. However, conventional MIMO channel estimation can not be directly extended to millimeter wave due to the constraints on cost-effective millimeter wave operation imposed on the number of available RF chains. Sparse subspace scanning techniques that search for the best subspace sample from the sounded subspace sampl","authors_text":"David J. Love, Taejoon Kim, Wei Zhang","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2019-04-16T07:52:42Z","title":"Sparse Subspace Decomposition for Millimeter Wave MIMO Channel Estimation"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.07515","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":"sha256:876341087127cd454938130a6dbd19d60a7e1e9c43398ca46b7989b4e7dff0b2","target":"record","created_at":"2026-05-17T23:48:25Z","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":"d7a86bc8130a72755d91f78fb789ac8e7d34533dd04c7f1187d6e8718c13e544","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2019-04-16T07:52:42Z","title_canon_sha256":"d9081e76c64458c6d55610056501dae815ee13d560c16fca9bdd4b8e3f4e18bd"},"schema_version":"1.0","source":{"id":"1904.07515","kind":"arxiv","version":1}},"canonical_sha256":"c1b7a7a22a93472b2b03010ea08acbff9f1ebd5a67a2210497f03adc605830cb","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"c1b7a7a22a93472b2b03010ea08acbff9f1ebd5a67a2210497f03adc605830cb","first_computed_at":"2026-05-17T23:48:25.016100Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:48:25.016100Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"/n7mzezh6537CCE8M8v7f72yywiwDFevaSomrCFLGL6kBcihmoW2nOzO7tdeumd9zQWf1mF1e0Urzn66DewRBw==","signature_status":"signed_v1","signed_at":"2026-05-17T23:48:25.016629Z","signed_message":"canonical_sha256_bytes"},"source_id":"1904.07515","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:876341087127cd454938130a6dbd19d60a7e1e9c43398ca46b7989b4e7dff0b2","sha256:0170852946662d95514256ed9ddf5ca083291a9f1bd3b8c85eaf48deddcfe1b5"],"state_sha256":"5ad2dfc67636ce9b5d62665d5129ef2e4d187392cb35fcd450bf65e239422163"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"BcJM4hY5Aw8aRRzSUIM9jgyv/8NxlcYsl42TKEddki+hPDMyY8pUOPqYtOansAS9vMBMrr8z2KCvg4wLxciXBQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-04T15:25:40.145347Z","bundle_sha256":"2fb9071ff1ec4f2dfc331015413b6c6d61d1713ede586b73d9421876ea29c2de"}}