{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2017:O23DBUA3ILB33SOESYEJL6VAPY","short_pith_number":"pith:O23DBUA3","canonical_record":{"source":{"id":"1706.03294","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-06-11T01:30:19Z","cross_cats_sorted":["math.IT"],"title_canon_sha256":"3d70c36e56f5eb778752d1834e953225ab7f7b7604cb167beb7422a0a358913b","abstract_canon_sha256":"4101c2218e565cf952d136dde5d260dc0dfce8e0dd0186fb9da1b6860a674e33"},"schema_version":"1.0"},"canonical_sha256":"76b630d01b42c3bdc9c4960895faa07e2a73c58d949b27ab77bb0ba3765069cf","source":{"kind":"arxiv","id":"1706.03294","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1706.03294","created_at":"2026-05-18T00:40:23Z"},{"alias_kind":"arxiv_version","alias_value":"1706.03294v3","created_at":"2026-05-18T00:40:23Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1706.03294","created_at":"2026-05-18T00:40:23Z"},{"alias_kind":"pith_short_12","alias_value":"O23DBUA3ILB3","created_at":"2026-05-18T12:31:34Z"},{"alias_kind":"pith_short_16","alias_value":"O23DBUA3ILB33SOE","created_at":"2026-05-18T12:31:34Z"},{"alias_kind":"pith_short_8","alias_value":"O23DBUA3","created_at":"2026-05-18T12:31:34Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2017:O23DBUA3ILB33SOESYEJL6VAPY","target":"record","payload":{"canonical_record":{"source":{"id":"1706.03294","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-06-11T01:30:19Z","cross_cats_sorted":["math.IT"],"title_canon_sha256":"3d70c36e56f5eb778752d1834e953225ab7f7b7604cb167beb7422a0a358913b","abstract_canon_sha256":"4101c2218e565cf952d136dde5d260dc0dfce8e0dd0186fb9da1b6860a674e33"},"schema_version":"1.0"},"canonical_sha256":"76b630d01b42c3bdc9c4960895faa07e2a73c58d949b27ab77bb0ba3765069cf","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:40:23.676143Z","signature_b64":"wvZT3YYA56BzY4fPQE8/LytJr3wMNQ5jG9r9Y9f2WokM9mtHH5JRXRF6k9FarYXX0kAn9BZDwSlvGSYhguiyDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"76b630d01b42c3bdc9c4960895faa07e2a73c58d949b27ab77bb0ba3765069cf","last_reissued_at":"2026-05-18T00:40:23.675270Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:40:23.675270Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1706.03294","source_version":3,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:40:23Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"hsOS7Bs6agczK9n6Lhd/QE+HJzIDLpcABwj/uXfcXMn+16SkBYtXDTTlPfUZN2COhD0ZnzGS6NbbpS1t8Py3AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-30T21:14:55.380044Z"},"content_sha256":"3a48a543deb57f1c163a526c1781e0e236d858f0278d787db1c617a86a9b42fe","schema_version":"1.0","event_id":"sha256:3a48a543deb57f1c163a526c1781e0e236d858f0278d787db1c617a86a9b42fe"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2017:O23DBUA3ILB33SOESYEJL6VAPY","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Downlink Precoding for Massive MIMO Systems Exploiting Virtual Channel Model Sparsity","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["math.IT"],"primary_cat":"cs.IT","authors_text":"Ender Ayanoglu, Thomas Ketseoglou","submitted_at":"2017-06-11T01:30:19Z","abstract_excerpt":"In this paper, the problem of designing a forward link linear precoder for Massive Multiple-Input Multiple-Output (MIMO) systems in conjunction with Quadrature Amplitude Modulation (QAM) is addressed. First, we employ a novel and efficient methodology that allows for a sparse representation of multiple users and groups in a fashion similar to Joint Spatial Division and Multiplexing. Then, the method is generalized to include Orthogonal Frequency Division Multiplexing (OFDM) for frequency selective channels, resulting in Combined Frequency and Spatial Division and Multiplexing, a configuration "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1706.03294","kind":"arxiv","version":3},"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":"2026-05-18T00:40:23Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"j5To/qscmGdV0ooZZWPEuY1EfhEXpNWVWuBeQKFyzrFLn1wr1gN0wjXfikHLrKD4aWWg+souzhZaSqWrF6NdAg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-30T21:14:55.380411Z"},"content_sha256":"f744827e0bb0f2864c1672e87e817411d4623b0c44180cc9a16960b595c871e9","schema_version":"1.0","event_id":"sha256:f744827e0bb0f2864c1672e87e817411d4623b0c44180cc9a16960b595c871e9"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/O23DBUA3ILB33SOESYEJL6VAPY/bundle.json","state_url":"https://pith.science/pith/O23DBUA3ILB33SOESYEJL6VAPY/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/O23DBUA3ILB33SOESYEJL6VAPY/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":"2026-05-30T21:14:55Z","links":{"resolver":"https://pith.science/pith/O23DBUA3ILB33SOESYEJL6VAPY","bundle":"https://pith.science/pith/O23DBUA3ILB33SOESYEJL6VAPY/bundle.json","state":"https://pith.science/pith/O23DBUA3ILB33SOESYEJL6VAPY/state.json","well_known_bundle":"https://pith.science/.well-known/pith/O23DBUA3ILB33SOESYEJL6VAPY/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2017:O23DBUA3ILB33SOESYEJL6VAPY","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":"4101c2218e565cf952d136dde5d260dc0dfce8e0dd0186fb9da1b6860a674e33","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-06-11T01:30:19Z","title_canon_sha256":"3d70c36e56f5eb778752d1834e953225ab7f7b7604cb167beb7422a0a358913b"},"schema_version":"1.0","source":{"id":"1706.03294","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1706.03294","created_at":"2026-05-18T00:40:23Z"},{"alias_kind":"arxiv_version","alias_value":"1706.03294v3","created_at":"2026-05-18T00:40:23Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1706.03294","created_at":"2026-05-18T00:40:23Z"},{"alias_kind":"pith_short_12","alias_value":"O23DBUA3ILB3","created_at":"2026-05-18T12:31:34Z"},{"alias_kind":"pith_short_16","alias_value":"O23DBUA3ILB33SOE","created_at":"2026-05-18T12:31:34Z"},{"alias_kind":"pith_short_8","alias_value":"O23DBUA3","created_at":"2026-05-18T12:31:34Z"}],"graph_snapshots":[{"event_id":"sha256:f744827e0bb0f2864c1672e87e817411d4623b0c44180cc9a16960b595c871e9","target":"graph","created_at":"2026-05-18T00:40:23Z","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":"In this paper, the problem of designing a forward link linear precoder for Massive Multiple-Input Multiple-Output (MIMO) systems in conjunction with Quadrature Amplitude Modulation (QAM) is addressed. First, we employ a novel and efficient methodology that allows for a sparse representation of multiple users and groups in a fashion similar to Joint Spatial Division and Multiplexing. Then, the method is generalized to include Orthogonal Frequency Division Multiplexing (OFDM) for frequency selective channels, resulting in Combined Frequency and Spatial Division and Multiplexing, a configuration ","authors_text":"Ender Ayanoglu, Thomas Ketseoglou","cross_cats":["math.IT"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-06-11T01:30:19Z","title":"Downlink Precoding for Massive MIMO Systems Exploiting Virtual Channel Model Sparsity"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1706.03294","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":"sha256:3a48a543deb57f1c163a526c1781e0e236d858f0278d787db1c617a86a9b42fe","target":"record","created_at":"2026-05-18T00:40:23Z","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":"4101c2218e565cf952d136dde5d260dc0dfce8e0dd0186fb9da1b6860a674e33","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-06-11T01:30:19Z","title_canon_sha256":"3d70c36e56f5eb778752d1834e953225ab7f7b7604cb167beb7422a0a358913b"},"schema_version":"1.0","source":{"id":"1706.03294","kind":"arxiv","version":3}},"canonical_sha256":"76b630d01b42c3bdc9c4960895faa07e2a73c58d949b27ab77bb0ba3765069cf","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"76b630d01b42c3bdc9c4960895faa07e2a73c58d949b27ab77bb0ba3765069cf","first_computed_at":"2026-05-18T00:40:23.675270Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:40:23.675270Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"wvZT3YYA56BzY4fPQE8/LytJr3wMNQ5jG9r9Y9f2WokM9mtHH5JRXRF6k9FarYXX0kAn9BZDwSlvGSYhguiyDQ==","signature_status":"signed_v1","signed_at":"2026-05-18T00:40:23.676143Z","signed_message":"canonical_sha256_bytes"},"source_id":"1706.03294","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:3a48a543deb57f1c163a526c1781e0e236d858f0278d787db1c617a86a9b42fe","sha256:f744827e0bb0f2864c1672e87e817411d4623b0c44180cc9a16960b595c871e9"],"state_sha256":"deffa85705e5ae50e3d2599893d349d42cc4c8e3be2d53e29e60377a27b65e47"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"U3oPydRkoOQC77fjndHOIBHF0Pa863yrFfYVaEaYlJGuLaEkuB0PhHRQ/4ukzVM/L2FVUfCPHeHOtu67H1LUCg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-30T21:14:55.382546Z","bundle_sha256":"b001b6f717cbc602aa921e444b7bbb9ba5cbcde1346974f0fd4257b22e6ce1e8"}}