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In this paper, we propose GR-Fall, a fall detection system with integrated gait recognition designed for indoor environments using single-input, single-output mmWave radar. To achieve high performance in various environments, we develop a data augmentation algorithm for target heatmaps and a cross-attention-based heatmap fusion framework for efficient fall detection. Furthermore, we introduce an innovative fall alarm mechanism based on joint fall-gait detection. This mechanism activates alerts when a person is detected having difficulty moving after a fall, thus minimizing unnecessary alarms and reducing strain on community resources. To evaluate GR-Fall, we recruit 33 volunteers and collect 5,799 instances across four different environments. Experimental results show that GR-Fall achieves 98.1% precision and 98.7% recall in new environments and with new participants, outperforming other state-of-the-art heatmap-based methods.<\/jats:p>","DOI":"10.1145\/3749471","type":"journal-article","created":{"date-parts":[[2025,9,15]],"date-time":"2025-09-15T13:26:32Z","timestamp":1757942792000},"page":"1-26","update-policy":"https:\/\/doi.org\/10.1145\/crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["GR-Fall: A Fall Detection System with Gait Recognition for Indoor Environments Using SISO mmWave Radar"],"prefix":"10.1145","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-4285-1905","authenticated-orcid":false,"given":"Chengzhen","family":"Meng","sequence":"first","affiliation":[{"name":"University of Science and Technology of China, Hefei, Anhui, China"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-2330-3799","authenticated-orcid":false,"given":"Chenming","family":"He","sequence":"additional","affiliation":[{"name":"University of Science and Technology of China, Hefei, Anhui, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0877-4636","authenticated-orcid":false,"given":"Dequan","family":"Wang","sequence":"additional","affiliation":[{"name":"University of Science and Technology of China, Hefei, Anhui, China"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-7896-6632","authenticated-orcid":false,"given":"Yuxuan","family":"Xiao","sequence":"additional","affiliation":[{"name":"University of Science and Technology of China, Hefei, Anhui, China"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-5524-1025","authenticated-orcid":false,"given":"Lingyu","family":"Wang","sequence":"additional","affiliation":[{"name":"University of Science and Technology of China, Hefei, Anhui, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6368-9250","authenticated-orcid":false,"given":"Xiaoran","family":"Fan","sequence":"additional","affiliation":[{"name":"Sunnyvale, California, USA"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-9630-1172","authenticated-orcid":false,"given":"Lu","family":"Zhang","sequence":"additional","affiliation":[{"name":"Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, Anhui, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9046-798X","authenticated-orcid":false,"given":"Yanyong","family":"Zhang","sequence":"additional","affiliation":[{"name":"University of Science and Technology of China, Hefei, Anhui, China and Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, Anhui, China"}]}],"member":"320","published-online":{"date-parts":[[2025,9,3]]},"reference":[{"key":"e_1_2_1_1_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pmcj.2012.08.003"},{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.compbiomed.2022.105626"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1109\/TAES.2015.140549"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1109\/CVPR52688.2022.00116"},{"key":"e_1_2_1_5_1","doi-asserted-by":"publisher","DOI":"10.1145\/130385.130401"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1145\/3610902"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1109\/ISAC.2010.5670478"},{"key":"e_1_2_1_8_1","doi-asserted-by":"publisher","DOI":"10.1109\/RADAR42522.2020.9114719"},{"key":"e_1_2_1_9_1","doi-asserted-by":"publisher","DOI":"10.1109\/TGRS.2019.2908758"},{"key":"e_1_2_1_10_1","doi-asserted-by":"publisher","DOI":"10.1109\/IEEE-IWS.2019.8804036"},{"key":"e_1_2_1_11_1","doi-asserted-by":"publisher","DOI":"10.1109\/TCE.2020.3021398"},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1109\/ICASSP.2018.8461512"},{"key":"e_1_2_1_13_1","unstructured":"Martin Ester Hans-Peter Kriegel J\u00f6rg Sander Xiaowei Xu et al. 1996. 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