{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2015:JZ5E2LQRWWEVIWUNLLHH6UFN4S","short_pith_number":"pith:JZ5E2LQR","canonical_record":{"source":{"id":"1509.05093","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2015-09-17T01:06:15Z","cross_cats_sorted":["math.IT"],"title_canon_sha256":"d4d88ba03a3a16e75f695bc1a1492c1f7636bf4f28b299c8bcec7cedb769e9ba","abstract_canon_sha256":"72f24a174a05c7cfdd6454db2ecc707db3fa2d5f7708c3a85b32ef641db77497"},"schema_version":"1.0"},"canonical_sha256":"4e7a4d2e11b589545a8d5ace7f50ade4be0fdfb821623e6c01c291dcaccbbe0e","source":{"kind":"arxiv","id":"1509.05093","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1509.05093","created_at":"2026-05-18T01:32:49Z"},{"alias_kind":"arxiv_version","alias_value":"1509.05093v1","created_at":"2026-05-18T01:32:49Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1509.05093","created_at":"2026-05-18T01:32:49Z"},{"alias_kind":"pith_short_12","alias_value":"JZ5E2LQRWWEV","created_at":"2026-05-18T12:29:27Z"},{"alias_kind":"pith_short_16","alias_value":"JZ5E2LQRWWEVIWUN","created_at":"2026-05-18T12:29:27Z"},{"alias_kind":"pith_short_8","alias_value":"JZ5E2LQR","created_at":"2026-05-18T12:29:27Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2015:JZ5E2LQRWWEVIWUNLLHH6UFN4S","target":"record","payload":{"canonical_record":{"source":{"id":"1509.05093","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2015-09-17T01:06:15Z","cross_cats_sorted":["math.IT"],"title_canon_sha256":"d4d88ba03a3a16e75f695bc1a1492c1f7636bf4f28b299c8bcec7cedb769e9ba","abstract_canon_sha256":"72f24a174a05c7cfdd6454db2ecc707db3fa2d5f7708c3a85b32ef641db77497"},"schema_version":"1.0"},"canonical_sha256":"4e7a4d2e11b589545a8d5ace7f50ade4be0fdfb821623e6c01c291dcaccbbe0e","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:32:49.934335Z","signature_b64":"ysPeZpKfEQCpSvQMHyvcCVUC7Kz9DRCsxW6O8wnnsJF+/vSo22O5XMu8NV5noRaHwt7/TvJcb7KXvP6WM9NTAQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"4e7a4d2e11b589545a8d5ace7f50ade4be0fdfb821623e6c01c291dcaccbbe0e","last_reissued_at":"2026-05-18T01:32:49.933909Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:32:49.933909Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1509.05093","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":"2026-05-18T01:32:49Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"1e59wulpLLz1hcnz/GAsITXvB26l3ohsi/aAcmJ+KJfUsV9Dd8dXejr3GzI0ngYjARdmonNYzl2ikig9Kod/Dw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T21:23:39.023185Z"},"content_sha256":"10b98fcd3d5e9ee74c225a7a38245fa09d6d1d2d04ad4dfd72d6e8a6bf4f5a12","schema_version":"1.0","event_id":"sha256:10b98fcd3d5e9ee74c225a7a38245fa09d6d1d2d04ad4dfd72d6e8a6bf4f5a12"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2015:JZ5E2LQRWWEVIWUNLLHH6UFN4S","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Pilot Contamination Mitigation for Wideband Massive MMO: Number of Cells Vs Multipath","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["math.IT"],"primary_cat":"cs.IT","authors_text":"Long Bao Le, Luc Vandendorpe, Tadilo Endeshaw Bogale, Xianbin Wang","submitted_at":"2015-09-17T01:06:15Z","abstract_excerpt":"This paper proposes novel joint channel estimation and beamforming approach for multicell wideband massive multiple input multiple output (MIMO) systems. Using our channel estimation and beamforming approach, we determine the number of cells $N_c$ that can utilize the same time and frequency resource while mitigating the effect of pilot contamination. The proposed approach exploits the multipath characteristics of wideband channels. Specifically, when the channel has $L$ multipath taps, it is shown that $N_c\\leq L$ cells can reliably estimate the channels of their user equipments (UEs) and per"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1509.05093","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":"2026-05-18T01:32:49Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ej1C0+S2mZSjaaLQ+Iz12yb1mgu7kYNPTmDiuXCMHPB3UdUYgVfnC/cX4b87AT30VKy7EfhxJ+cAJk7gqCa1Cw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T21:23:39.023886Z"},"content_sha256":"1964024cf82102a709a41ac5dec6f68b6f85438596d4d74da9c16a68fcce797e","schema_version":"1.0","event_id":"sha256:1964024cf82102a709a41ac5dec6f68b6f85438596d4d74da9c16a68fcce797e"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S/bundle.json","state_url":"https://pith.science/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S/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":"2026-05-28T21:23:39Z","links":{"resolver":"https://pith.science/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S","bundle":"https://pith.science/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S/bundle.json","state":"https://pith.science/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S/state.json","well_known_bundle":"https://pith.science/.well-known/pith/JZ5E2LQRWWEVIWUNLLHH6UFN4S/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2015:JZ5E2LQRWWEVIWUNLLHH6UFN4S","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":"72f24a174a05c7cfdd6454db2ecc707db3fa2d5f7708c3a85b32ef641db77497","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2015-09-17T01:06:15Z","title_canon_sha256":"d4d88ba03a3a16e75f695bc1a1492c1f7636bf4f28b299c8bcec7cedb769e9ba"},"schema_version":"1.0","source":{"id":"1509.05093","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1509.05093","created_at":"2026-05-18T01:32:49Z"},{"alias_kind":"arxiv_version","alias_value":"1509.05093v1","created_at":"2026-05-18T01:32:49Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1509.05093","created_at":"2026-05-18T01:32:49Z"},{"alias_kind":"pith_short_12","alias_value":"JZ5E2LQRWWEV","created_at":"2026-05-18T12:29:27Z"},{"alias_kind":"pith_short_16","alias_value":"JZ5E2LQRWWEVIWUN","created_at":"2026-05-18T12:29:27Z"},{"alias_kind":"pith_short_8","alias_value":"JZ5E2LQR","created_at":"2026-05-18T12:29:27Z"}],"graph_snapshots":[{"event_id":"sha256:1964024cf82102a709a41ac5dec6f68b6f85438596d4d74da9c16a68fcce797e","target":"graph","created_at":"2026-05-18T01:32:49Z","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":"This paper proposes novel joint channel estimation and beamforming approach for multicell wideband massive multiple input multiple output (MIMO) systems. Using our channel estimation and beamforming approach, we determine the number of cells $N_c$ that can utilize the same time and frequency resource while mitigating the effect of pilot contamination. The proposed approach exploits the multipath characteristics of wideband channels. Specifically, when the channel has $L$ multipath taps, it is shown that $N_c\\leq L$ cells can reliably estimate the channels of their user equipments (UEs) and per","authors_text":"Long Bao Le, Luc Vandendorpe, Tadilo Endeshaw Bogale, Xianbin Wang","cross_cats":["math.IT"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2015-09-17T01:06:15Z","title":"Pilot Contamination Mitigation for Wideband Massive MMO: Number of Cells Vs Multipath"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1509.05093","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":"sha256:10b98fcd3d5e9ee74c225a7a38245fa09d6d1d2d04ad4dfd72d6e8a6bf4f5a12","target":"record","created_at":"2026-05-18T01:32:49Z","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":"72f24a174a05c7cfdd6454db2ecc707db3fa2d5f7708c3a85b32ef641db77497","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2015-09-17T01:06:15Z","title_canon_sha256":"d4d88ba03a3a16e75f695bc1a1492c1f7636bf4f28b299c8bcec7cedb769e9ba"},"schema_version":"1.0","source":{"id":"1509.05093","kind":"arxiv","version":1}},"canonical_sha256":"4e7a4d2e11b589545a8d5ace7f50ade4be0fdfb821623e6c01c291dcaccbbe0e","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"4e7a4d2e11b589545a8d5ace7f50ade4be0fdfb821623e6c01c291dcaccbbe0e","first_computed_at":"2026-05-18T01:32:49.933909Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:32:49.933909Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"ysPeZpKfEQCpSvQMHyvcCVUC7Kz9DRCsxW6O8wnnsJF+/vSo22O5XMu8NV5noRaHwt7/TvJcb7KXvP6WM9NTAQ==","signature_status":"signed_v1","signed_at":"2026-05-18T01:32:49.934335Z","signed_message":"canonical_sha256_bytes"},"source_id":"1509.05093","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:10b98fcd3d5e9ee74c225a7a38245fa09d6d1d2d04ad4dfd72d6e8a6bf4f5a12","sha256:1964024cf82102a709a41ac5dec6f68b6f85438596d4d74da9c16a68fcce797e"],"state_sha256":"f89de9f22001c2f0450c581672e9f2beb30916e11270bd8a87d746c251968520"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"V0CBgotSebU+LyZ4CYytMow3snrL2g7ilrj0KjFM3taQmy8ozPPfveSkiwbWHo7+yDc+JBS9RSlJrojShTM+BQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-28T21:23:39.027777Z","bundle_sha256":"92240dc48e41bac69b07136d6b62fd01419e1b7cbda12fa0e893c894e21dd12b"}}