?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Li&rft.au=Li%2C+A&rft.aufirst=A&rft.volume=69&rft.date=January+2021&rft.atitle=Interference+Exploitation+Precoding+for+Multi-Level+Modulations%3A+Closed-Form+Solutions&rft.issue=1&rft.title=IEEE+Transactions+on+Communications&rft.pages=291-308&rft.genre=article