{"paper":{"title":"A Scalable 256-Antenna Distributed MIMO Testbed with Real-Time Fully Digital Beamforming","license":"http://creativecommons.org/licenses/by/4.0/","headline":"A distributed MIMO testbed scales to 256 antennas using 16 RFSoC boards for real-time fully digital beamforming.","cross_cats":["cs.SY","eess.SY"],"primary_cat":"eess.SP","authors_text":"Anders J Johansson, Baktash Behmanesh, Dumitra Iancu, Emil Bergman, Liang Liu, Lina Tinnerberg, Mikael Henriksson, Ove Edfors, Sijia Cheng, Vilgot Snygg","submitted_at":"2026-05-04T09:32:16Z","abstract_excerpt":"Distributed massive MIMO (D-MIMO) is a promising technology for future generation wireless systems as it takes advantage of both an increased array aperture and a decentralized processing architecture and topology. In order to truly understand the possibilities and limitations of these approaches in real scenarios, practical realization of testbeds is an essential step in the technology advancement. This work presents the Lund University Large Intelligent Surface testbed -- LuLIS, that can operate up to 256 coherent radio frequency (RF) chains using 16 AMD Zynq UltraScale RFSoC ZCU216 evaluati"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The system is easily scalable, as increasing the number of antennas is done in multiples of 16 by adding more RFSoCs, which also implies addition of another processing node. The design allows up-scaling without hardware redesign, introduction of large latencies or data transfer overhead.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That synchronization and coherence across distributed RFSoC nodes can be maintained at scale while keeping real-time performance and avoiding data-transfer bottlenecks when nodes are physically separated.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"The LuLIS testbed supports up to 256 antennas across 16 distributed RFSoC nodes with real-time FPGA-accelerated MIMO processing and demonstrates uplink operation from four single-antenna users at 64, 128, and 256 antennas.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A distributed MIMO testbed scales to 256 antennas using 16 RFSoC boards for real-time fully digital beamforming.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"870c7b933deb8180ea7413ddc005a91b474fdd593cab063077b697d5bf87b957"},"source":{"id":"2605.02388","kind":"arxiv","version":2},"verdict":{"id":"68a17a4c-86df-4f4e-8be5-f72799a2ce62","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-08T18:54:14.642750Z","strongest_claim":"The system is easily scalable, as increasing the number of antennas is done in multiples of 16 by adding more RFSoCs, which also implies addition of another processing node. The design allows up-scaling without hardware redesign, introduction of large latencies or data transfer overhead.","one_line_summary":"The LuLIS testbed supports up to 256 antennas across 16 distributed RFSoC nodes with real-time FPGA-accelerated MIMO processing and demonstrates uplink operation from four single-antenna users at 64, 128, and 256 antennas.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That synchronization and coherence across distributed RFSoC nodes can be maintained at scale while keeping real-time performance and avoiding data-transfer bottlenecks when nodes are physically separated.","pith_extraction_headline":"A distributed MIMO testbed scales to 256 antennas using 16 RFSoC boards for real-time fully digital beamforming."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.02388/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"ai_meta_artifact","ran_at":"2026-05-20T15:41:23.701050Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_title_agreement","ran_at":"2026-05-20T03:31:22.378559Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T16:24:03.857961Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"da1f5a8009ab8d5ce22f158436fb7ee26fb04943c520527c4f80b564d6a0d154"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":3,"snapshot_sha256":"ed8a85fada7fd410b2e22efa2c8fc5200ff837e1f4a6315ba2eb0311b0616dea"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}