{"paper":{"title":"WHTDM: Walsh-Hadamard Transform Division Multiplexing for Doubly-Selective Channels","license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","headline":"Walsh-Hadamard transform division multiplexing outperforms OFDM in high-mobility channels while cutting transmitter complexity by 2.5 times and eliminating all complex multipliers.","cross_cats":[],"primary_cat":"eess.SP","authors_text":"Chi Yonggang, Tan Chenxing, Wang Hao, Yuan Zhonghao, Yu Jiaxing, Zhang Kuang","submitted_at":"2026-05-14T07:23:22Z","abstract_excerpt":"We propose Walsh-Hadamard Transform Division Multiplexing (WHTDM), a multicarrier waveform that replaces the conventional IFFT/FFT pair in OFDM with a real-valued, unitary Walsh-Hadamard transform (WHT). WHTDM inherits the CP-OFDM transceiver structure while eliminating all complex multiplications from the transform stage, yielding a transmitter with zero real multipliers in the core modulation block. For detection under doubly-selective channels, we adopt a cross-domain memory approximate message passing (CD-MAMP) equalizer that operates on the banded structure of the equivalent WHT-domain ch"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"WHTDM with CD-MAMP significantly outperforms conventional OFDM 1-tap MMSE at high mobility, achieving over an order of magnitude lower BER at 120 km/h.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the equivalent WHT-domain channel matrix remains sufficiently banded for the CD-MAMP equalizer to deliver the reported gains under the specific 3GPP TDL-C model at 28 GHz.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"WHTDM replaces FFT with Walsh-Hadamard transform in OFDM, cuts transmitter complexity 2.5x and eliminates complex multipliers while delivering over an order of magnitude lower BER than 1-tap MMSE OFDM at 120 km/h via CD-MAMP equalization.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Walsh-Hadamard transform division multiplexing outperforms OFDM in high-mobility channels while cutting transmitter complexity by 2.5 times and eliminating all complex multipliers.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"3587a58e2f669d2c7e90e7fd61fbd5cd2f47ace2237900f82893db0e3f5b53fd"},"source":{"id":"2605.14482","kind":"arxiv","version":1},"verdict":{"id":"0690c1a7-3b3e-4d64-9206-f643bcb6b040","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T01:53:33.038885Z","strongest_claim":"WHTDM with CD-MAMP significantly outperforms conventional OFDM 1-tap MMSE at high mobility, achieving over an order of magnitude lower BER at 120 km/h.","one_line_summary":"WHTDM replaces FFT with Walsh-Hadamard transform in OFDM, cuts transmitter complexity 2.5x and eliminates complex multipliers while delivering over an order of magnitude lower BER than 1-tap MMSE OFDM at 120 km/h via CD-MAMP equalization.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the equivalent WHT-domain channel matrix remains sufficiently banded for the CD-MAMP equalizer to deliver the reported gains under the specific 3GPP TDL-C model at 28 GHz.","pith_extraction_headline":"Walsh-Hadamard transform division multiplexing outperforms OFDM in high-mobility channels while cutting transmitter complexity by 2.5 times and eliminating all complex multipliers."},"references":{"count":22,"sample":[{"doi":"","year":1990,"title":"Multicarrier modulation for data transmission: An idea whose time has come,","work_id":"43303853-bc36-4fa2-aafc-e6e61f980d7e","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1999,"title":"van Nee and R","work_id":"83e5ead7-7a9c-4d24-8702-f219296884d6","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2017,"title":"Orthogonal time frequency space modu- lation,","work_id":"13d10bff-7512-46a0-8a63-589ab7dc62b3","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2017,"title":"Orthogonal time fre- quency space (OTFS) modulation for millimeter-wave communications systems,","work_id":"48e2e689-359a-474d-aa01-4b5f542f09bd","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2021,"title":"Orthogonal time-frequency space modulation: A promising next-generation waveform,","work_id":"797fc8f3-f186-4e1d-9a63-d4c9798dbcd8","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":22,"snapshot_sha256":"1e74597abc9afd09c433e16f4d6770070157cc5a13b45500f089b50404d92515","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"42393b1fd1de1be2f15ce303caae6235ac3dda58213f19c42d9f1b41fa424313"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}