Invalidity dossier
US 5577024
Multiple access radio system
Current assignee: Nokia Oyj
Added 9/21/2026, 10:19:02 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US5577024A — "Multiple access radio system"
Bibliographic data (as supplied): US Patent 5,577,024; application US08/543,690, filed 1995-10-16; granted/publication date 1996-11-19; priority date 1993-07-08; inventors Esa Malkamaki and Harri Jokinen; original assignee Nokia Mobile Phones Ltd; current assignee listed as Nokia Oyj; status "Expired – Lifetime" (anticipated expiration 2014-05-23). Classifications include H04L1/16, H04L1/18, H04L5/06, H04L5/26, H04L25/0224, and H04W72/044.
Purpose: The patent addresses a multiple access radio system, particularly transmitting short, infrequent information — such as message acknowledgments (ARQ) or channel allocation requests — from mobiles to a base station in a TDMA digital cellular system. The stated problem is that reserving a dedicated time slot per user wastes capacity when such transmissions are infrequent, while letting several users share one slot causes collisions that destroy all simultaneous acknowledgments. In the up-link direction this is worse because mobiles cannot mutually coordinate.
Plain-language scope: The invention provides channels usable by a sole concurrent user, or by plural concurrent users on mutually distinguishable subchannels. In a TDMA time slot of predetermined length, mobiles communicating with the same base station use substantially orthogonal transmissions — e.g., distinct, substantially orthogonal bit sequences (code access) — to send information of a few or several bits, typically 1 to 10 bits. This avoids collisions or allows recovery, since overlapping orthogonal signals remain detectable. Related aspects cover dividing a TDMA slot into shorter slots, on-off-type acknowledgments (positive/negative), base-station-to-mobile orthogonal transmissions, and a digital transmitter generating a predetermined bit sequence within a TDMA burst and a receiver with at least one correlator to detect several different bit sequences. The summary also states the Finnish application FI-925472 concerns a combined CDMA/TDMA method using complementary (perfectly orthogonal) spreading codes.
What the excerpt does not establish: It omits full claim text, complete description and figures (FIG. 1, FIG. 2 are only named), detailed embodiments, prosecution history, and any legal conclusions. Legal status, assignee accuracy, and dates are expressly assumptions per the source. Source: https://patents.google.com/patent/[US5577024](/patent/US5577024)/en
Generated 10/1/2026, 10:01:50 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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