Prior art — US Patent 6628629

Analysis of Prior Art for U.S. Patent No. 6,628,629

Date of Analysis: May 12, 2026

Patent Under Examination:

Patent Number: US 6,628,629 B1
Title: Reservation based prioritization method for wireless transmission of latency and jitter sensitive IP-flows in a wireless point to multi-point transmission system
Filing Date: July 9, 1999
Issue Date: September 30, 2003
Assignee: Malibu Networks Inc.
Inventor: Jacob W. Jorgensen

This report details the most relevant prior art cited in the prosecution of U.S. Patent No. 6,628,629, assessing its potential to anticipate the independent claims under 35 U.S.C. § 102.

Summary of Independent Claims of US 6,628,629

The patent's core invention is a method and system for providing Quality of Service (QoS) in a wireless network by using an "advanced reservation algorithm." This algorithm prioritizes and schedules data packets, particularly for latency- and jitter-sensitive IP flows like voice and video. It achieves this by reserving slots in future transmission frames to ensure a consistent, or isochronous, data flow.

Claim 1 & 38 (Method Claims): Describe a method for providing isochronous data packets in a wireless point-to-multipoint (PtMP) system. This involves using an "advanced reservation algorithm" to reserve a first slot in a future frame and a second slot in a subsequent frame for an IP flow, ensuring consistent timing.
Claim 14 & 50 (System Claims): Describe a system comprising a base station, subscriber equipment, and a "resource allocation means." This system implements the "advanced reservation algorithm" to reserve slots in future transmission frames to manage QoS for IP flows.
Claim 26 (Computer-Readable Medium Claim): Pertains to a storage medium with instructions for a processor to execute the method of claim 1.

Analysis of Cited Prior Art

The following prior art references were cited during the prosecution of the '629 patent. An analysis of their potential impact on the patent's claims is provided below.

1. U.S. Patent 5,859,850: "Scheduling of isochronous traffic in a wireless ATM communication system"

Publication Date: January 12, 1999
Filing Date: June 14, 1996
Assignee: AT&T Corp.
Brief Description: This patent discloses a method for scheduling isochronous (time-sensitive) traffic in a wireless Asynchronous Transfer Mode (ATM) network. It describes a scheduler that grants transmission "permits" to remote terminals for specific time slots in a frame. The system uses a "reservation field" in the uplink frame for terminals to request bandwidth, and the base station scheduler allocates resources based on these requests and the Quality of Service (QoS) requirements of the traffic.
Potential Anticipation of Claims:
- Claims 1, 14, 26, 38, 50: This patent appears highly relevant. It describes a reservation-based system for allocating bandwidth in a wireless network to handle time-sensitive (isochronous) data. The "scheduler" in the '850 patent functions similarly to the "resource allocation means" and "advanced reservation algorithm" in the '629 patent. The '850 patent's method of granting permits for future time slots based on requests is a form of "advanced reservation" to ensure QoS. An argument for anticipation could be made that this prior art teaches the core concept of reserving future slots for isochronous data streams in a point-to-multipoint wireless system, even though it specifies ATM rather than IP. However, the '629 patent's focus on "IP-flows" may be considered a specific application not explicitly detailed in the '850 patent.

2. U.S. Patent 6,005,856: "Method for dynamic bandwidth allocation for providing constant bit rate service in a broadband wireless communication system"

Publication Date: December 21, 1999
Filing Date: April 28, 1997
Assignee: Hughes Electronics Corporation
Brief Description: This patent details a dynamic bandwidth allocation scheme for a wireless communication system to support Constant Bit Rate (CBR) services, which are inherently latency and jitter-sensitive (e.g., voice and video). The system uses a scheduler at the base station to allocate time slots in a Time Division Multiple Access (TDMA) frame to different subscriber units based on their bandwidth requests. It explicitly mentions reserving future slots to maintain a constant data rate.
Potential Anticipation of Claims:
- Claims 1, 14, 26, 38, 50: This reference is also highly relevant. It clearly discloses a system and method for reserving future time slots in a wireless network to provide a specific Quality of Service (constant bit rate), which is a key element of the '629 patent's claims. The concept of a central scheduler (at the base station) managing resource allocation for multiple subscribers based on service requirements is directly taught. The distinction may lie in the specific term "advanced reservation algorithm," but the functionality described in the '856 patent appears to be substantially the same.

3. U.S. Patent 5,956,330: "Scheduling transmission of data packets in a communications network"

Publication Date: September 21, 1999
Filing Date: February 27, 1997
Assignee: Nortel Networks Corporation
Brief Description: This patent describes a method for scheduling data packets in a communication network, including wireless networks. It focuses on a scheduling mechanism that considers the quality of service requirements for different types of traffic. The system uses a scheduler to determine the transmission order of packets from various queues, giving priority to delay-sensitive data.
Potential Anticipation of Claims:
- Claims 1, 14, 26, 38, 50: This patent discloses the general concept of QoS-based scheduling in a packet-switched network. While it doesn't explicitly focus on "reserving" slots in future frames in the same "isochronous" manner as the '629 patent, its discussion of prioritizing latency-sensitive packets through scheduling provides a strong foundation for an argument of obviousness, if not direct anticipation. The key difference may be the '629 patent's more specific "advanced reservation" for subsequent frames.

4. "A New Scheduling Algorithm for QoS Support in Wireless ATM Networks" by J. M. Hah, et al. (IEEE VTC 1998)

Publication Date: May 1998
Brief Description: This academic paper proposes a scheduling algorithm called "Fair-Queuing with-Controlled-Delay" (FQCD) for providing Quality of Service (QoS) in wireless ATM networks. The algorithm aims to guarantee delay and jitter bounds for real-time traffic (like voice and video) while also ensuring fairness for non-real-time data traffic. It involves mechanisms for classifying traffic and scheduling cell transmissions based on their QoS requirements.
Potential Anticipation of Claims:
- Claims 1, 14, 26, 38, 50: This paper, published more than a year before the '629 patent's filing date, describes a sophisticated scheduling algorithm for managing different traffic types in a wireless network to meet specific QoS parameters, including delay and jitter. This directly addresses the core problem that the '629 patent's "advanced reservation algorithm" aims to solve. While the context is ATM, the principles of traffic classification, prioritization, and scheduling to maintain QoS are directly applicable to IP-based systems. This reference could be used to argue that the concepts in the '629 patent were known in the art.

Conclusion

The prior art cited against U.S. Patent No. 6,628,629, particularly U.S. Patents 5,859,850 and 6,005,856, and the J. M. Hah et al. paper, disclose key elements of the invention claimed in the patent. These references describe reservation-based scheduling mechanisms for allocating bandwidth in wireless networks to support time-sensitive (isochronous) data and ensure Quality of Service.

The core novelty of the '629 patent appears to reside in the specific implementation or the "advanced" nature of its reservation algorithm, especially as applied to IP-based point-to-multipoint systems. However, a detailed analysis by a person skilled in the art would be required to determine if the specific limitations of the '629 patent's claims are fully anticipated by these prior art documents. The fact that the patent was granted suggests that the patent examiner found novel and non-obvious distinctions, but the cited art is nonetheless highly relevant. The subsequent PTAB proceedings (IPR2018-00727 and PGR2022-00051) further indicate that the validity of these claims has been a subject of significant legal and technical scrutiny.