Mention the year in which 'Code-Division OFDM Joint Communication and Sensing System for 6G Machine-Type Communication' was published.
What year was 'Code-Division OFDM Joint Communication and Sensing System for 6G Machine-Type Communication' published?
SELECT DISTINCT ?answer WHERE { <https://dblp.org/rec/journals/iotj/ChenFWZY21> <https://dblp.org/rdf/schema#yearOfPublication> ?answer }
<https://dblp.org/rec/journals/iotj/ChenFWZY21>