{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2020:XCVR5FJOO7SLOM5WL5ZGGWCLSL","short_pith_number":"pith:XCVR5FJO","canonical_record":{"source":{"id":"2009.09729","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2020-09-21T10:04:07Z","cross_cats_sorted":[],"title_canon_sha256":"a22c994d68cec61acc5887e53df902d13b09071354edf0908a539eb42ce2e70d","abstract_canon_sha256":"a3637326d6833eb8a0518a1c3f03d8bd75532a89c7f40295b9f23c567e6fbb38"},"schema_version":"1.0"},"canonical_sha256":"b8ab1e952e77e4b733b65f7263584b92e26f5797ab081d7afa5392370b3bf7bb","source":{"kind":"arxiv","id":"2009.09729","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2009.09729","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"arxiv_version","alias_value":"2009.09729v1","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2009.09729","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"pith_short_12","alias_value":"XCVR5FJOO7SL","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"pith_short_16","alias_value":"XCVR5FJOO7SLOM5W","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"pith_short_8","alias_value":"XCVR5FJO","created_at":"2026-07-05T01:36:52Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2020:XCVR5FJOO7SLOM5WL5ZGGWCLSL","target":"record","payload":{"canonical_record":{"source":{"id":"2009.09729","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2020-09-21T10:04:07Z","cross_cats_sorted":[],"title_canon_sha256":"a22c994d68cec61acc5887e53df902d13b09071354edf0908a539eb42ce2e70d","abstract_canon_sha256":"a3637326d6833eb8a0518a1c3f03d8bd75532a89c7f40295b9f23c567e6fbb38"},"schema_version":"1.0"},"canonical_sha256":"b8ab1e952e77e4b733b65f7263584b92e26f5797ab081d7afa5392370b3bf7bb","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T01:36:52.519403Z","signature_b64":"Aq2A80gRUsuE1l4i1+3yWa13756CFEGWrXAIxTaRdOImHucbjN1NEM28IS5l8OqpYZPkflwLOxGuE/UQiAkzBg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"b8ab1e952e77e4b733b65f7263584b92e26f5797ab081d7afa5392370b3bf7bb","last_reissued_at":"2026-07-05T01:36:52.518970Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T01:36:52.518970Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2009.09729","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":"2026-07-05T01:36:52Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"l5UEMcdSuP18eE/na/z9R6p0KDj4+fTuLEnWKsBkziF/5aEahZ4mdPqk1aWIgIZtJreU43R9fuKAf5U//jBeBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-06T15:19:46.500425Z"},"content_sha256":"f5bc22cc73520a6370ce3fe21a0d0acfad8e8dd53cab0847218c491e7f5b596a","schema_version":"1.0","event_id":"sha256:f5bc22cc73520a6370ce3fe21a0d0acfad8e8dd53cab0847218c491e7f5b596a"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2020:XCVR5FJOO7SLOM5WL5ZGGWCLSL","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Low-Complexity Massive MIMO Tensor Precoding","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"eess.SP","authors_text":"Andr\\'e L. F. de Almeida, Lucas N. Ribeiro, Martin Haardt, Stefan Schwarz","submitted_at":"2020-09-21T10:04:07Z","abstract_excerpt":"We present a novel and low-complexity massive multiple-input multiple-output (MIMO) precoding strategy based on novel findings concerning the subspace separability of Rician fading channels. Considering a uniform rectangular array at the base station, we show that the subspaces spanned by the channel vectors can be factorized as a tensor product between two lower dimensional subspaces. Based on this result, we formulate tensor maximum ratio transmit and zero-forcing precoders. We show that the proposed tensor precoders exhibit lower computational complexity and require less instantaneous chann"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2009.09729","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2009.09729/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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":"2026-07-05T01:36:52Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ktel7QY2kIwSiv1wCWTsMz2Tkd6/BQgUp8EG+PnqnAUIxAnjcSJ+A1wBSAULMNMOpj2Y0N/XBoeeMEJXDRhiDA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-06T15:19:46.500839Z"},"content_sha256":"c3d84ce71676b8107e5bd51ac94c117ca6244e4332ab796f61ebf9c14495f088","schema_version":"1.0","event_id":"sha256:c3d84ce71676b8107e5bd51ac94c117ca6244e4332ab796f61ebf9c14495f088"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL/bundle.json","state_url":"https://pith.science/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL/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":"2026-07-06T15:19:46Z","links":{"resolver":"https://pith.science/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL","bundle":"https://pith.science/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL/bundle.json","state":"https://pith.science/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL/state.json","well_known_bundle":"https://pith.science/.well-known/pith/XCVR5FJOO7SLOM5WL5ZGGWCLSL/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2020:XCVR5FJOO7SLOM5WL5ZGGWCLSL","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":"a3637326d6833eb8a0518a1c3f03d8bd75532a89c7f40295b9f23c567e6fbb38","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2020-09-21T10:04:07Z","title_canon_sha256":"a22c994d68cec61acc5887e53df902d13b09071354edf0908a539eb42ce2e70d"},"schema_version":"1.0","source":{"id":"2009.09729","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2009.09729","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"arxiv_version","alias_value":"2009.09729v1","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2009.09729","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"pith_short_12","alias_value":"XCVR5FJOO7SL","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"pith_short_16","alias_value":"XCVR5FJOO7SLOM5W","created_at":"2026-07-05T01:36:52Z"},{"alias_kind":"pith_short_8","alias_value":"XCVR5FJO","created_at":"2026-07-05T01:36:52Z"}],"graph_snapshots":[{"event_id":"sha256:c3d84ce71676b8107e5bd51ac94c117ca6244e4332ab796f61ebf9c14495f088","target":"graph","created_at":"2026-07-05T01:36:52Z","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"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2009.09729/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"We present a novel and low-complexity massive multiple-input multiple-output (MIMO) precoding strategy based on novel findings concerning the subspace separability of Rician fading channels. Considering a uniform rectangular array at the base station, we show that the subspaces spanned by the channel vectors can be factorized as a tensor product between two lower dimensional subspaces. Based on this result, we formulate tensor maximum ratio transmit and zero-forcing precoders. We show that the proposed tensor precoders exhibit lower computational complexity and require less instantaneous chann","authors_text":"Andr\\'e L. F. de Almeida, Lucas N. Ribeiro, Martin Haardt, Stefan Schwarz","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2020-09-21T10:04:07Z","title":"Low-Complexity Massive MIMO Tensor Precoding"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2009.09729","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:f5bc22cc73520a6370ce3fe21a0d0acfad8e8dd53cab0847218c491e7f5b596a","target":"record","created_at":"2026-07-05T01:36:52Z","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":"a3637326d6833eb8a0518a1c3f03d8bd75532a89c7f40295b9f23c567e6fbb38","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2020-09-21T10:04:07Z","title_canon_sha256":"a22c994d68cec61acc5887e53df902d13b09071354edf0908a539eb42ce2e70d"},"schema_version":"1.0","source":{"id":"2009.09729","kind":"arxiv","version":1}},"canonical_sha256":"b8ab1e952e77e4b733b65f7263584b92e26f5797ab081d7afa5392370b3bf7bb","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"b8ab1e952e77e4b733b65f7263584b92e26f5797ab081d7afa5392370b3bf7bb","first_computed_at":"2026-07-05T01:36:52.518970Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T01:36:52.518970Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"Aq2A80gRUsuE1l4i1+3yWa13756CFEGWrXAIxTaRdOImHucbjN1NEM28IS5l8OqpYZPkflwLOxGuE/UQiAkzBg==","signature_status":"signed_v1","signed_at":"2026-07-05T01:36:52.519403Z","signed_message":"canonical_sha256_bytes"},"source_id":"2009.09729","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:f5bc22cc73520a6370ce3fe21a0d0acfad8e8dd53cab0847218c491e7f5b596a","sha256:c3d84ce71676b8107e5bd51ac94c117ca6244e4332ab796f61ebf9c14495f088"],"state_sha256":"e707bcdc871f82e26f163f43b45cc3c1d39bf60318ee45a2ef2b622327ab4386"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Pv0qrzo6083zQKWaNbeSxjl/La0tKHj0TN4pJJW8kuqQN/xZOCyVy1KJ7342pGZ/gh0nZIVwrtM3d+8eTHSwBg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-07-06T15:19:46.502973Z","bundle_sha256":"8d8516ae22cc983297ceccf5465a5e75aa6022757d18d336825a892dee5d4cc9"}}