US 6801579

I'll search for litigation/docket information and verify details for this specific patent number.

Let me check for any Federal Circuit docket activity in 2026 and USPTO records specific to this patent.

US Patent 6,801,579 B1 — Analyst Summary

Sourcing note: The patent's full text and bibliographic data were taken from the Google Patents record (https://patents.google.com/patent/[US6801579](/patent/US6801579)/en). I ran targeted searches for any 2026 CAFC docket or USPTO proceeding specifically naming 6801579. I found no authoritative record of a 2026 Federal Circuit appeal or other 2026 litigation involving this exact patent number. The only third-party hits were (a) reference to "6801579" in unrelated PTAB IPR exhibits (as citation material) and (b) Brazilian design registration "DI 6801579-8," which is a different, unrelated identifier (a footwear design, Wolverine World Wide) and must not be conflated with the US patent. Treat absence of 2026 docket results as "not found," not as proof of non-existence.

Bibliographic Data

Abstract (paraphrased)

A method for wireless transmission from an array of two or more antennas in which each transmitted signal is selected from a constellation of unitary space-time signals. Each signal is a unitary matrix whose columns represent antennas, rows represent time intervals, and elements represent complex amplitudes. In embodiments, the constellation matrices form a non-Abelian group with positive diversity product, or a coset of such a group; alternatively the constellation is a subset whose multiplicative closure is such a group; still alternatively the constellation is an extension adding elements outside the group.

Plain-Language Overview of Independent Claims

Transmitter-side claims (1, 8, 9, 12): each recites selecting a signal from a constellation of unitary-matrix signals, then transmitting from two or more antennas across two or more time intervals, with amplitudes proportional to the matrix elements (rows = time intervals, columns = antennas; claim 12 limits to exactly two antennas).

• Claim 1 — Selection made from a constellation whose matrices are any one of: (I) a non-Abelian group, other than a quaternion group, having a positive diversity product; (II) a subset of such a non-Abelian group whose multiplicative closure is itself such a group; (III) a coset of (I) formed by left, right, or both multiplications; or (IV) a coset of (II).
• Claim 8 — Selection from a constellation at least half of which corresponds to matrices expressible as products A^l B^k (or cosets). A is an n×n diagonal matrix of integer powers of an m-th root of unity; B is an n×n shift-type matrix with a root-of-unity entry (e^(2πi/s)) in the bottom-left; with s, m positive integers, n ≥ 2, l < m, and k < min(s, n). (This tracks the specification's generalization of group G_{m,r} to the non-group set S_{m,s}.)
• Claim 9 — Selection from a constellation at least half of which corresponds to matrices expressible as pairwise products of elements of two unitary representations of finite groups G_A and G_B, or cosets thereof. (Dependent claims 10–11 add that the groups are fixed-point-free, and that G_A = G_B as equivalent reducible representations of an odd-order group.)
• Claim 12 — Two-antenna method using a "Hamiltonian" constellation: at least half the signals are 2×2 unitary matrices of the form [[x, −y*],[y, x*]], with |x|² + |y|² = 1, and the set includes at least one matrix where ‖x| − |y‖ > 0 (i.e., |x| ≠ |y|). Dependent claim 13 requires that difference to be at least 0.1.

Receiver-side claims (14, 21, 22, 25): mirror claims 1, 8, 9, and 12 respectively, but recite the receive method — receiving the multi-antenna, multi-interval signal and comparing it against the constellation to identify which selected signal was sent (i.e., the detection/decoding counterpart). Corresponding dependents: 15–20, 23–24, 26.

Notable Literal-Reading Items (no auto-correction applied)

The claims contain drafting irregularities worth flagging if analyzing claim scope verbatim:

• Claim 1 (and claim 14) recite "guaternion group" in element (II) while element (I) uses "quaternion group," and both use "quaternion group" in the exclusions — i.e., the exclusion from non-Abelian groups applies to quaternion groups.
• Claim 12 lists element "(m)" rather than "(III)," and has a reversed-bracket typo in the matrix: [x -y* / y x*. ].
• Claim 8 describes B as a "diagonal matrix" although the depicted matrix is a cyclic-shift (companion) matrix; claim 8 also states "i = −1" whereas claim 21 states "i² = −1."

Uncertainty / Limitations

• Assignee history is per recorded assignments (Lucent → Alcatel-Lucent → WSOU Investments, with Nokia of America listed); I did not independently verify current chain of title beyond the record.
• The patent is expired (adjusted expiration 2022-12-21), which materially limits the practical significance of any 2026 enforcement activity.
• I could not confirm any CAFC 2026 docket naming 6801579; the docket results I retrieved concerned other patents and parties. If a current 2026 docket exists, it was not surfaced by these searches and would need direct PACER/CAFC or Docket Navigator verification.