Invalidity dossier
US 5533019
Packet data in an analog cellular radiotelephone system
Current assignee: Motorola Mobility LLC
Added 9/23/2026, 7:31:11 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,533,019 A
Title: "Packet data in an analog cellular radiotelephone system"
Assignee / Inventor: Original assignee Motorola, Inc.; inventor Jay P. Jayapalan (recorded as "JAYAPALAN, JAY PURUSHOTHAMAN"). The listing also records later reassignments to Motorola Mobility, Inc. (2010) and Motorola Mobility LLC (2012), reflected in the current-assignee field.
Key dates: Filed 1994-01-31 (application US08/189,522); priority 1994-01-31; granted/published 1996-07-02; anticipated expiration 2014-01-31; status "Expired – Lifetime." Related foreign/PCT filings listed: FI954571A, PCT/US1994/014686, CA2156636A/C, JP7520605A, SE9503360A.
Purpose: The patent addresses problems in sending data over analog cellular (AMPS) systems, where FM techniques such as companding and preemphasis, plus multipath fading and handoffs, make landline modems unreliable. Prior packet data systems (e.g., CDPD) relied on packet-switching to route data to an end-system data processor, which conserves channels but limits bandwidth for longer transfers such as file or facsimile transmissions. The stated solution is to communicate packet data over a circuit-switched channel.
Plain-language scope: The system includes a base station with voice and data transceivers; a base site controller operable to establish a circuit-switched packet-data call connection between a mobile data unit and a data end system; and a mobile data unit with data-call circuitry for requesting/establishing a circuit-switched data connection or a single-user "hybrid" data channel, plus packet-data circuitry for communicating packet data over that connection or channel. The description further covers packet-switched, circuit-switched, and hybrid modes; channel assignment by the BSC; routing via an interworking function and MSC to the PSTN or via an MD-IS to a data network; and connectionless protocols (e.g., TCP/IP) for the hybrid channel.
What the excerpt does not establish: It contains only the abstract, description fragments, and bibliographic/classification data; it does not include the full claims, the complete written description, or drawing contents. It therefore does not establish the precise claim scope, completeness of the specification, or Figs. 1–5 details beyond the brief descriptions given. Classifications listed are H04W72/12, H04W76/10, and H04L12/64.
Generated 10/1/2026, 9:41:59 PM
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Litigation summary
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PTAB challenges
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Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
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Extensions
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Derivative works
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