Invalidity dossier
US 5675581
Simulating user interference in a spread spectrum communication network
Current assignee: Qualcomm Inc
Added 9/23/2026, 4:41:53 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 5,675,581 A
Title: Simulating user interference in a spread spectrum communication network
Inventor: Samir S. Soliman
Assignee: Qualcomm Inc. (original and current assignee listed)
Application number: US 08/601,491
Priority date: 1994-07-13; Filing date: 1996-02-14; Publication/grant date: 1997-10-07
Legal status: Expired – Lifetime; anticipated expiration 2014-07-13 (legal status stated as an assumption, not a legal conclusion).
Source: https://patents.google.com/patent/US5675581/en
Purpose. In CDMA cellular systems, subscriber units transmit over the same bandwidth regardless of location, so interference estimates bear directly on system capacity, where maximum capacity occurs when each user's E_b/N_t is at the minimum needed for a desired channel signal-to-noise ratio. Determining the interference level at maximum capacity by field tests would require a full ensemble of mobile units—a logistics problem that could preclude complete system calibration when fewer units were available. The invention therefore provides a method and apparatus for simulating signal interference in a multi-channel communication system, preferably CDMA spread spectrum, with users in multiple cells communicating via at least one base station having a receiver in a first cell.
Plain-language scope. The method determines a first composite signal power equal to the sum of power transmitted by a first set of simulated users (typically in the first cell), determines a first normalized data rate for that composite signal, generates a first interference signal at a power level based on the composite power and normalized data rate, optionally adjusts it per average power fluctuation from closed-loop power control, and feeds it into the base station receiver(s). A second composite power and normalized data rate for simulated users in other cells yield a second interference signal that can modify the first. The first interference signal is typically synthesized as electrical noise over a predetermined band, preferably with relatively uniform spectral density, with power adjusted per the product of the first composite power and first normalized data rate. A Gaussian random variable sequence may model variations in the composite signal. Apparatus elements include a power selection element, a data rate generation element, and a first interference signal generator coupled to both.
Not established by the excerpt. The full claim set, dependent-claim details, drawing content, embodiments beyond those summarized, and the omitted apparatus description are not established here; the excerpt is expressly partial.
Generated 10/1/2026, 9:44:18 PM
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