United States Cellular Corporation (UScellular) — now renamed Array Digital Infrastructure, Inc. (NYSE: AD, formerly USM) — is a Chicago-based wireless communications company founded in 1983. It has been a majority-owned subsidiary of Telephone and Data Systems, Inc. (NYSE: TDS), which held roughly 83% of its common shares through early 2025 and about 81% after the August 2025 sale of the wireless business. As of December 31, 2024, UScellular reported approximately 4,100 employees, 4.4 million retail connections across parts of 21 states, 4,409 owned towers, and total revenues of about $3.7 billion (Wireless plus Towers segments).
Operations. UScellular operated a regional wireless network providing postpaid and prepaid voice, data, and device sales to consumer, business, and government customers, and as a tower owner it leased space on its towers to third-party carriers. On May 28, 2024, it agreed to sell its wireless operations and select spectrum assets to T-Mobile US for approximately $4.4 billion (cash plus assumed debt), plus a separate ~$1.0 billion spectrum sale to Verizon. The T-Mobile transaction closed August 1, 2025, after which the company renamed itself Array Digital Infrastructure and repositioned as a shared wireless infrastructure (tower) owner/operator.
Patent-litigation posture. The tracked data show UScellular as a defendant in both appearances and never as a plaintiff — the classic profile of an operating company defending infringement claims rather than asserting patents. The sole tracked matter, Freedom Wireless, Inc. v. Alltel Corp. et al (2:06-cv-00504), was filed November 30, 2006, in the plaintiff-friendly U.S. District Court for the Eastern District of Texas, Marshall Division, and terminated in 2010.
Case context. Freedom Wireless was a small Phoenix-based, individual-inventor-started patent asserter that sued multiple carriers and vendors over prepaid-cellular patents (notably the "Security Cellular Telecommunications System" family, including U.S. Patents 6,157,823, 5,822,437-type claims, and 6,157,823/'067/'851). UScellular appeared alongside co-defendants including Alltel, Cricket Communications, Comverse, and VeriSign. The prepaid-billing technology focus of the suit reflects the litigation wave over prepaid wireless account-credit methods in that period.