ARRIS Group Inc v. Mobile Telecommunications Technologies LLC

1. Case Identification

• Case #: IPR2016-00766
• Patent #: 5,659,891
• Filed: March 16, 2016
• Petitioner(s): ARRIS Group, Inc.
• Patent Owner(s): Mobile Telecommunications Technologies, LLC
• Challenged Claims: 1-5

2. Patent Overview

• Title: Multicarrier Techniques in Bandlimited Channels
• Brief Description: The ’891 patent discloses a method of multicarrier modulation using co-located transmitters to increase transmission capacity for mobile paging systems. The technique operates multiple paging carriers within a single, mask-defined, bandlimited channel while remaining consistent with FCC emission mask limits.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 are anticipated by [Petrovic](https://ai-lab.exparte.com/case/ptab/IPR2016-00766/doc/1013) under 35 U.S.C. §102.

• Prior Art Relied Upon: Petrovic (a 1993 IEEE paper titled "Permutation Modulation for Advanced Radio Paging").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Petrovic, a paper co-authored by two inventors of the ’891 patent, describes a nearly identical system and discloses every limitation of claims 1-5. Petrovic teaches a "multicarrier permutation modulation technique" for simulcast paging networks, proposing the use of eight subcarriers within a band-limited channel. This channel is defined by moving "emission mask boundaries" to create a 35 kHz pass band with 7.5 kHz guard bands on each side, directly corresponding to the claimed "single mask-defined, bandlimited channel."
  • Petitioner contended that Petrovic explicitly discloses the key frequency relationship that was the basis for the patent’s allowance. Petrovic teaches that the frequency difference between the outermost carrier and the band edge is at least 7.5 kHz (the guard band), while half the frequency difference between adjacent carriers is 2.5 kHz (half of the 5 kHz carrier spacing). As 7.5 kHz is greater than 2.5 kHz, this core limitation is met. For dependent claims 2 and 4, Petrovic’s figures illustrate that the transmitted signal between adjacent subchannels does not return to zero, showing the required overlap. For claim 5, Petrovic’s disclosure of combining outputs from multiple "subtransmitters" and sending them to a "common antenna" was argued to meet the limitation of co-locating transmitters emanating from the same source.

Ground 2: Claim 5 is obvious over Petrovic in view of [Raith](https://ai-lab.exparte.com/case/ptab/IPR2016-00766/doc/1014) and [Alakija](https://ai-lab.exparte.com/case/ptab/IPR2016-00766/doc/1015) under 35 U.S.C. §103.

• Prior Art Relied Upon: Petrovic (1993 IEEE paper), Raith (International Publication No. WO 89/08355), and Alakija (a 1992 IEEE conference paper).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was presented as an alternative in the event the Board adopts a narrower construction of "plurality of transmitters" where Petrovic's "subtransmitters" do not qualify. Under this construction, Petrovic discloses a paging system with two transmitters located seven miles apart. Raith teaches cellular mobile telephone systems where it is common to co-locate base station transmitters to service adjacent or contiguous cells. Alakija teaches that combining the feeds from multiple co-located transmitters into a single antenna structure provides significant advantages. Petitioner argued that the combination of these references renders the co-location limitation of claim 5 obvious.
  • Motivation to Combine: A POSITA would combine Petrovic with Raith's teachings to expand the experimental paging system described in Petrovic to a larger commercial network covering multiple adjacent cells. This expansion would naturally lead to co-locating transmitters to serve contiguous cells, a standard practice taught by Raith. A POSITA would then be motivated to integrate Alakija's single-antenna design for these co-located transmitters to realize the well-understood benefits of hardware savings, lower manufacturing costs, and reduced installation costs.
  • Expectation of Success: The proposed combination involved applying well-known and compatible techniques from the wireless and cellular communication arts to a known paging system. A POSITA would have had a reasonable expectation of success in integrating these elements to create the system recited in claim 5.

4. Key Claim Construction Positions

Petitioner asserted that several claim terms were central to the invalidity analysis and proposed the following constructions, noting that they were consistent with constructions adopted by the Board in prior IPRs involving the ’891 patent or agreed upon in district court litigation.

• "single mask-defined, bandlimited channel" (Claims 1, 3, 5): Proposed construction is "a channel confined to a frequency range."
• "plurality of transmitters" (Claim 5): Proposed construction is "at least two transmitters."
• "transmitter(s)" (Claim 5): Proposed construction is "structural unit(s) for generating and modulating a signal to be transmitted." This construction is central to the alternative obviousness argument in Ground 2.
• "band edge" (Claims 1, 3, 5): Proposed construction is "a band edge of the single mask-defined, bandlimited channel."
• "operating a plurality of paging carriers" (Claims 1, 3): Proposed construction is "operating two or more transmission signals that are modulated to carry paging information."

5. Relief Requested

• Petitioner requests the institution of an inter partes review and the cancellation of claims 1-5 of Patent 5,659,891 as unpatentable.