US 5859850

Patent Overview — US 5,859,850

Title: "Elastic store circuit for composite cells switched through an ATM network."

Inventor: Robert Leroy Lien. Original assignee: Lucent Technologies Inc. Application number: US08/579,706. Prior art / priority and filing date: 1995-12-28. Publication (grant) date: 1999-01-12. Legal status listing: Expired – Lifetime, with anticipated expiration noted at 2015-12-28.

Purpose and plain-language scope: ATM networks can carry synchronous (STM) time-slotted voice traffic inside "composite cells," whose payloads hold up to 48 time slots, one channel per octet. Composite cells must be sent isochronously — at a regular, quasi-synchronous rate — but ATM transport jitter and delay can push a cell into a later frame period, so cells may arrive out of order (illustrated by cell x1 in FIG. 1A). The described invention is an "elastic store" that receives such isochronous ATM composite cells, groups them with other cells of the originally transmitted frame, removes jitter and delay, re-orders any delayed cell into its proper group, and reassembles each group into a corresponding STM frame of data.

In the described apparatus (FIG. 3), a FIFO router 104 — containing a cell pass counter 106 and an SRAM 108 — keeps a modulo-N count of each VCI and routes each incoming cell into one of N FIFOs (e.g., FIFO 110₁, 110₂); the count's most significant bit, a "rollover bit," is written into the FIFO as a flag. A controllable oscillator adjusts to a FIFO's fill level to clock cells out through an output sequencer. The text states the scheme is expandable "to provide an arbitrary amount of jitter delay," with dejitter capability in microseconds given as (N)(125), and that elastic stores would be most applicable in network end-node access circuits.

Source: https://patents.google.com/patent/US5859850/en

What the supplied excerpt does not establish: It provides no full claims, no complete detailed description, no prior-art comparison, and no figures. It does not establish the exact N used in the described embodiment (the text breaks off mid-sentence at "N is two"!), nor independent validity, enforceability, or current ownership beyond the listed assignments.