Derivative works

An analysis of this patent's claims, prosecution history, and relevant prior art is essential for understanding its scope and validity.

File Wrapper and Prosecution History Analysis

• Date: May 13, 2026
• Patent Analyst: Senior US Patent Analyst
• Subject: Analysis of Prosecution History for U.S. Patent 9,667,337

Overview:
U.S. Patent 9,667,337, which issued from application Ser. No. 14/540,773, is a continuation of a long chain of applications dating back to a provisional application filed on August 22, 2003. This extended prosecution history is significant, as it indicates a prolonged negotiation with the USPTO to secure the claims.

Key Prosecution Events:
The application that matured into the '337 patent was filed on November 13, 2014. During its examination, the USPTO examiner issued a non-final rejection, citing prior art related to Quality of Service (QoS) in wireless networks, particularly standards like IEEE 802.11e and early products that implemented traffic prioritization.

The primary arguments from the examiner focused on the obviousness of combining known repeater technology with existing QoS protocols. The examiner contended that a person of ordinary skill in the art would have been motivated to add QoS features to a wireless repeater to improve performance for emerging real-time applications like VoIP and video streaming.

Applicant's Arguments for Patentability:
In response to the rejection, the applicant, Theodore S. Rappaport, amended the claims to more precisely define the "intelligent" aspects of the relay. The arguments for patentability hinged on the specific architecture disclosed, which included a controller, memory, and processing pipeline capable of more than just standards-based QoS. The applicant emphasized the ability of the repeater to:

1. Selectively filter and "kill" data from undesired sources (e.g., spam, security threats), a feature not explicitly managed by standard MAC-layer QoS.
2. Modify data streams before retransmission to insert or alter watermarks, network IDs, or security keys.
3. Gather and report detailed network statistics, including traffic analysis and security breach attempts, back to a host device or network controller.

The applicant successfully argued that while standards like 802.11e provided a framework for prioritizing known traffic types, the invention provided a more flexible and powerful system for active network management, security, and traffic shaping within a repeater itself. The claims were ultimately allowed based on these distinguishing features that went beyond simple, pre-defined QoS queuing.

Conclusion:
The prosecution history reveals that the patent's novelty does not reside in the basic idea of prioritizing traffic in a wireless relay. Instead, its strength lies in the claims that describe a repeater with an intelligent control architecture capable of deep packet inspection, data modification, and security functions. Any analysis of the patent's validity must focus on prior art that discloses not just QoS, but also these advanced, programmable filtering and management capabilities within a stand-alone repeater device.

Claim Chart Analysis for US Patent 9,667,337

Prior Art Reference: Drafts of the IEEE P802.11e/D4.0 standard, "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Medium Access Control (MAC) Enhancements for Quality of Service (QoS)," available before the priority date of August 22, 2003.

Invalidity Thesis: Independent Claim 1 of the '337 patent is anticipated by or, in the alternative, rendered obvious by the combination of well-known wireless repeater technology and the QoS mechanisms publicly disclosed in the draft IEEE 802.11e standard prior to August 22, 2003.

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Claim 1 Element	Disclosed by Prior Art?	Mapping and Rationale from IEEE P802.11e/D4.0 Draft & Other References
1a: A method performed by a wireless relay device.	Yes	The concept of a wireless relay or "repeater" was well-established. The patent's own background section cites commercially available examples like the Buffalo Technology repeater (Announced Jun. 17, 2003) and the SMC Networks SMC2671W (Announced Jun. 6, 2003). Their function was to receive and retransmit wireless signals to extend network range, which discloses a method performed by such a device.
1b: Receiving a data transmission.	Yes	This is a fundamental function of any wireless device, including a repeater. By definition, a repeater must receive a data transmission to retransmit it. The 802.11e draft specifies the complete MAC and PHY layer protocols for receiving wireless frames.
1c: Analyzing the received data to determine an application type associated with the data.	Yes	The IEEE 802.11e draft explicitly taught this. It introduced Access Categories (ACs) to classify traffic, mapping data packets to User Priorities (UPs) and then to four ACs: Voice (AC_VO), Video (AC_VI), Best Effort (AC_BE), and Background (AC_BK). This classification is a direct analysis to determine application type, often based on existing 802.1p or DSCP tags in the packet headers.
1d: Prioritizing retransmission of the data based on the determined application type.	Yes	This is the core purpose of the 802.11e standard's QoS enhancements. The Enhanced Distributed Coordination Function (EDCF) prioritizes medium access based on the Access Category. Each AC uses different channel access parameters (AIFSN, CWmin, etc.) to give higher-priority traffic a statistically greater chance of being transmitted first. This directly teaches prioritizing transmission based on the determined application type.
1e: The prioritization is based on one or more pre-set instructions.	Yes	The EDCF parameters for each Access Category are the "pre-set instructions." These parameters are broadcast by a QoS Access Point (QAP) in its beacon frames. A device, such as a repeater, would receive these pre-set values and use them to govern its transmission logic for each class of traffic. The configuration utilities for prior art repeaters also allowed users to set operational rules.
1f: Retransmitting the data according to the prioritization.	Yes	A repeater implementing the 802.11e EDCF mechanism would inherently perform this step. After receiving and classifying a packet (1c), it would contend for the medium to retransmit it using the prioritized EDCF rules (1d) based on pre-set parameters (1e). A packet classified as "Voice" would be retransmitted with less delay than one classified as "Background," fulfilling this limitation.

Final Assessment:
The combination of a standard repeater function with the QoS mechanisms of the IEEE 802.11e draft discloses every element of Claim 1. A person of ordinary skill in the art in 2003, faced with the need to improve performance for real-time applications over a repeated wireless link, would have found it obvious to implement the emerging 802.11e QoS standard in a repeater. Therefore, Claim 1 is likely invalid.