How Wireless Routers Manage Traffic Between Old and New Devices
A method for wireless access points to prevent older, slower Wi-Fi devices from clogging the network connection for newer, faster devices.
Original patent title: “Minimization of performance impact in overlying 802.11b and 802.11g networks”
A method for wireless access points to prevent older, slower Wi-Fi devices from clogging the network connection for newer, faster devices. Granted to Lenovo Singapore Pte Ltd in 2008 with 21 claims and 1 forward citation, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent describes a traffic management system for wireless access points that handle multiple Wi-Fi protocols, specifically 802.11b and 802.11g. Because 802.11b devices cannot 'see' the signals used by faster 802.11g traffic, they often transmit data at the same time, causing collisions and slowdowns. The invention uses a flow controller to maintain specific timers for each protocol. By delaying traffic from the slower protocol until the timer for the faster protocol expires, the access point ensures that high-speed data packets are not interrupted by legacy devices.
The gap
What does this patent NOT cover?
- Does not cover network traffic management that relies solely on hardware-level signal filtering without software-based timers.
- Does not cover protocols other than those utilizing physical vs. virtual carrier-sense mechanisms (like 802.11b/g).
- Does not cover client-side traffic management; it is strictly limited to the access point (router) side.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The system treats the incompatibility as a timing problem rather than a signal problem, using a flow controller to force 'blind' devices to wait until the faster protocol's transmission window is clear.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Legacy Wi-Fi access points supporting mixed 802.11b/g environments
Early 2000s wireless routers from manufacturers like IBM or Lenovo
Why it matters
The bigger picture
When 802.11g was introduced, it was significantly faster than the older 802.11b standard, but they shared the same frequency. This patent provided a way to maintain backward compatibility without forcing the entire network to drop to the slower 802.11b speed, which was a major pain point for early wireless network performance.
Filed
December 19, 2003
Granted
April 1, 2008
Market context
Who's building on this
Companies in this space
The core principles of protocol isolation are now standard in modern Wi-Fi chipsets from companies like Qualcomm, Broadcom, and Intel. While this specific patent is older, the logic of managing mixed-speed traffic remains fundamental to how modern routers handle legacy IoT devices alongside high-speed Wi-Fi 6 clients.
Market impact
This patent helped stabilize the transition period between 802.11b and 802.11g, allowing businesses to upgrade their infrastructure incrementally. It prevented the 'slowest device penalty' where one old laptop could degrade the entire office network's speed.
Claim 1 — Plain English
What this patent covers
This patent describes a traffic management system for wireless access points that handle multiple Wi-Fi protocols, specifically 802.11b and 802.11g. Because 802.11b devices cannot 'see' the signals used by faster 802.11g traffic, they often transmit data at the same time, causing collisions and slowdowns. The invention uses a flow controller to maintain specific timers for each protocol. By delaying traffic from the slower protocol until the timer for the faster protocol expires, the access point ensures that high-speed data packets are not interrupted by legacy devices.
The clever bit
The system treats the incompatibility as a timing problem rather than a signal problem, using a flow controller to force 'blind' devices to wait until the faster protocol's transmission window is clear.
What it does not cover
- Does not cover network traffic management that relies solely on hardware-level signal filtering without software-based timers.
- Does not cover protocols other than those utilizing physical vs. virtual carrier-sense mechanisms (like 802.11b/g).
- Does not cover client-side traffic management; it is strictly limited to the access point (router) side.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Early stage
Citation count
6/40
Early citations
Claim breadth
14/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
5/20
Granted 10–20 years ago
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$8K – $26K
Midpoint $16K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
0 independent claims · 1 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
21 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Cromer, D. C., Locker, H. J., & Jakes, P. J. (2008). How Wireless Routers Manage Traffic Between Old and New Devices (U.S. Patent No. 7,352,772). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/7352772/minimization-of-performance-impact-in-overlying-80211b-and-80211g-networks
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Wireless Routers Manage Traffic Between Old and New Devices cover?
A method for wireless access points to prevent older, slower Wi-Fi devices from clogging the network connection for newer, faster devices.
Who owns patent US 7352772?
Lenovo Singapore Pte Ltd owns this patent, granted in 2008.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 7352772 cited by?
This patent has been cited by 1 later patents that build on its ideas.
What problem does this patent solve?
When 802.11g was introduced, it was significantly faster than the older 802.11b standard, but they shared the same frequency. This patent provided a way to maintain backward compatibility without forcing the entire network to drop to the slower 802.11b speed, which was a major pain point for early wireless network performance.
What does this patent NOT cover?
Does not cover network traffic management that relies solely on hardware-level signal filtering without software-based timers.
Patent monitoring