PTAB

IPR2017-01887

Sprint Spectrum L.P. v. General Access Solutions, Ltd.

Title: Wireless Access System and Associated Method Using Multiple Modulation Formats in TDD Frames According to Subscriber Service Type
Brief Description: The ’810 patent discloses a burst packet transmission system for fixed wireless access networks. The system is designed to optimize bandwidth usage through base stations that employ time division duplex (TDD) communication and can dynamically and independently modulate uplink and downlink transmissions for each wireless access device based on changing channel conditions and the subscriber's service type.

Prior Art Relied Upon: Ahy (Patent 7,366,133) and Csapo (Patent 6,411,825).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Ahy teaches a fixed wireless access network with multiple base stations using TDD communication, where a base station controller (BSC) adaptively modifies a set of communication parameters (including modulation) for each customer premises equipment (CPE) to optimize the communication link. To supply the claimed "RF modem shelf," Petitioner turned to Csapo, which discloses the conventional physical architecture of a base station, including an RF front-end, modem processors, and a controller housed within a single "physical cabinet or housing." Petitioner contended this cabinet meets the "RF modem shelf" limitation.
- Motivation to Combine: A POSITA would combine Ahy’s adaptive communication system with Csapo’s disclosure of conventional base station hardware. Both references are directed to cellular communication systems managed by a base station. The combination represents the use of a known technique (Csapo’s hardware implementation) to improve a similar method (Ahy’s adaptive system), which would have yielded predictable results.
- Expectation of Success: A POSITA would have a reasonable expectation of success because implementing Ahy's control logic on the standard, functionally compatible base station hardware described by Csapo is a straightforward integration of known elements.

Prior Art Relied Upon: Ahy (Patent 7,366,133), Csapo (Patent 6,411,825), and Sanders (an IEEE 802.16 standards contribution).
Core Argument for this Ground:
- Prior Art Mapping: This ground builds on the Ahy and Csapo combination from Ground 1 and adds Sanders to teach limitations related to adapting modulation based on "service type." Petitioner asserted that Sanders discloses a physical (PHY) layer for a TDD system that can support a Bandwidth-On-Demand MAC sublayer. Sanders teaches partitioning a TDM frame into channels based on traffic type or Quality of Service (QoS) and applying flexible communication parameters, such as modulation and forward error correction (FEC), based on "class of service objectives."
- Motivation to Combine: A POSITA would be motivated to add Sanders's service-class-based parameter allocation to the Ahy/Csapo system to improve QoS and overall system efficiency. This combination applies a known method of service differentiation to a known adaptive system to achieve the predictable result of a more robust and flexible network.

Prior Art Relied Upon: Klein (an IEEE 802.16 standards contribution).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Klein, a proposal for the IEEE 802.16 standard, teaches a broadband wireless access system using TDD frames with distinct uplink and downlink subframes. Klein explicitly discloses "subscriber level adaptive modulation (SLAM)," where the modulation scheme (e.g., QPSK, QAM-16) is dynamically set for each subscriber based on their individual link conditions. Petitioner contended that an RF modem is an inherent component of Klein’s base station and that an "RF modem shelf" is an obvious, necessary structure for housing the modem components, well known to a POSITA.
- Motivation to Combine (for inherent shelf): A POSITA would have understood that implementing the PHY layer detailed in Klein required using a standard base station architecture, which inherently includes modems housed in a cabinet or shelf. Therefore, adding a shelf to Klein’s system was not a matter of invention but a simple implementation of a well-known, standard component.

Prior Art Relied Upon: Klein (IEEE 802.16.1pc-00/09) and Sanders (IEEE 802.16.1pc-00/02).
Core Argument for this Ground:
- Prior Art Mapping: This ground combines Klein's adaptive modulation system with Sanders's teachings on service-type differentiation. While Klein teaches adapting modulation based on channel quality, it fails to explicitly link these adaptations to different service types. Sanders remedies this by disclosing a system where PHY parameters, including modulation and FEC, are flexibly coupled with information flows based on "class of service objectives," such as different target bit error rates (BER) for different types of traffic.
- Motivation to Combine: A POSITA would combine the complementary teachings of Klein and Sanders, both of which were proposals for the same IEEE 802.16 standard. Combining Klein's adaptation to channel conditions with Sanders's adaptation to service requirements would be an obvious path to creating a more efficient and versatile system.
- Expectation of Success: A POSITA would have a high expectation of success in combining these known solutions, as both were designed for interoperability within the same TDD framework and addressed complementary aspects of adaptive wireless communication.

Petitioner argued that the term "RF modem shelf" should be construed as "a physical structure to support or contain one or more RF modems." This construction is central to Petitioner's obviousness arguments, particularly in Ground 1, as it allows the term to encompass the "physical cabinet or housing" for modem processors disclosed in prior art like Csapo, which does not use the specific word "shelf."

Petitioner requests the institution of an inter partes review and the cancellation of claims 1-14 of Patent 6,891,810 as unpatentable.