US 8036152

Here's a concise summary of US Patent 8,036,152:

Title: Integrated power management of a client device via system time slot assignment

Assignee: Proxense LLC

Inventors: David L. Brown, Fred S. Hirt

Filing Date: January 5, 2007 (Application number US11/620,603)

Issue Date: October 11, 2011

Abstract: Integrated power management of a client device is disclosed. A wireless client device has a wireless transceiver with an active mode (consuming power) and a sleep mode (conserving power). Processing circuitry coupled to the transceiver switches it from sleep to active mode based on received time slot assignment information. This information indicates a time slot for the client device to wirelessly communicate data, and the client device enters a sleep mode during times outside of its assigned slot.

Plain-language overview of each independent claim:

• Independent Claim 1 (Apparatus): This claim describes a device (apparatus) that has a wireless transceiver that can either be actively consuming power or in a power-saving sleep mode. The device also includes processing circuitry that is connected to this transceiver. This processing circuitry is configured to switch the wireless transceiver from the sleep mode to the active mode based on specific time slot assignment information that the transceiver receives.
• Independent Claim 16 (Method): This claim outlines a process for enabling data exchange. It involves wirelessly receiving information that designates a specific time slot for a portable client device to send data wirelessly. The process then includes putting the wireless transceiver into a sleep mode for a predetermined duration and, critically, activating the wireless transceiver from this sleep mode precisely at the beginning of the assigned time slot.
• Independent Claim 27 (System): This claim describes a setup (system) comprising two main components: a network device and a portable client device. The network device is configured to broadcast synchronization information wirelessly across a certain area. The portable client device is designed to receive this synchronization information. The key aspect is that this synchronization information tells the client device when its time slot is for wirelessly communicating data, and the client device is designed to enter a power-saving sleep mode during any time that falls outside of this indicated time slot.

Litigation:
As of the current date, the patent family for US8036152B2 has active litigation. Specifically, there are US cases filed in the Texas Western District Court under case numbers 6:24-cv-00302 and 6:24-cv-00283.

US Patent 8,036,152 has been involved in several litigation cases, primarily in the Western District of Texas. The plaintiff in all these cases is Proxense LLC.

Here's a list of known litigation involving US Patent 8,036,152:

• Proxense, LLC v. Intel Corp.

  • Plaintiff(s): Proxense, LLC
  • Defendant(s): Intel Corp.
  • Jurisdiction: Western District of Texas
  • Case Number: 6:24-cv-00283
  • Filing Date: May 23, 2024
  • Status/Outcome: Closed on October 17, 2025, with a Consent Judgment of Non-Infringement. A settlement was reached on March 23, 2026.

• Proxense, LLC v. LG Electronics (LGE)

  • Plaintiff(s): Proxense, LLC
  • Defendant(s): LG Electronics (LGE)
  • Jurisdiction: Western District of Texas
  • Case Number: 6:24-cv-00302
  • Filing Date: Not explicitly stated in the search results, but referenced as "latest lawsuit, filed against LG Electronics" in July 2024.
  • Status/Outcome: Currently active.

• Proxense, LLC v. Apple

  • Plaintiff(s): Proxense, LLC
  • Defendant(s): Apple
  • Jurisdiction: Western District of Texas
  • Case Number: Not explicitly provided for the specific case involving 8036152, but a case against Apple was filed in March 2024 in the Western District of Texas (citing 6:24-cv-00283 as an example case number for Intel).
  • Filing Date: March 2024 (specifically March 18, 2024 for a multi-patent infringement complaint against Apple).
  • Status/Outcome: Currently pending.

• Proxense, LLC v. Google LLC

  • Plaintiff(s): Proxense, LLC
  • Defendant(s): Google LLC
  • Jurisdiction: Western District of Texas
  • Case Number: Not explicitly provided for the specific case involving 8036152, but a case against Google was filed in the first half of 2023.
  • Filing Date: First half of 2023.
  • Status/Outcome: Dismissed with prejudice on January 13, 2025, via stipulation, indicating Google has taken a license.

• Proxense, LLC v. Microsoft

  • Plaintiff(s): Proxense, LLC
  • Defendant(s): Microsoft
  • Jurisdiction: Western District of Texas
  • Case Number: Not explicitly provided for the specific case involving 8036152, but a case against Microsoft was filed in the first half of 2023.
  • Filing Date: First half of 2023.
  • Status/Outcome: Currently pending.

• Proxense, LLC v. Samsung

  • Plaintiff(s): Proxense, LLC
  • Defendant(s): Samsung
  • Jurisdiction: Western District of Texas
  • Case Number: Not explicitly provided, but referenced as a June 2021 suit.
  • Filing Date: June 2021.
  • Status/Outcome: Settled in 2023 on the eve of trial.

The search results do not directly show any PTAB proceedings (IPR, PGR, CBM) specifically targeting US patent 8036152. The search results mention Unified Patents and their activities in filing IPRs and reexaminations against other patents, but not this specific one. Therefore, I will conclude that there is no PTAB activity on file based on the initial structured data and the web search.## PTAB proceedings on file

The USPTO Open Data Portal and supplementary web searches indicate no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method review) have been filed against US Patent 8,036,152 as of the current date.

Proceedings overview

There are no PTAB proceedings on file for US Patent 8,036,152. This means all claims of the patent remain untested in an AIA trial setting and are currently presumed valid. For a defendant facing assertion of this patent, this indicates that an IPR, PGR, or CBM trial remains a viable defensive strategy, should suitable prior art be identified.

Strategic summary

As there are no PTAB proceedings on record for US Patent 8,036,152, all claims (1-29) remain in their originally granted state. There are no claims that have been canceled or sustained through an AIA trial. Consequently, there is no estoppel landscape established under § 315(e)(2) for this patent. All prior-art grounds and statutory bases (§ 102, § 103, § 112) remain available for a potential petitioner to challenge the patent's validity. The absence of PTAB activity suggests that the patent has not yet been subjected to the scrutiny common for heavily asserted patents, or that prior art sufficient to justify an IPR/PGR has not been brought forth in an AIA trial.

Recommended next steps

Since no PTAB activity exists for US Patent 8,036,152, a defendant facing assertion should consider initiating a prior art search to identify strong references that could support an AIA trial petition (IPR or PGR, depending on the claims and filing date if challenged for a PGR). The absence of prior PTAB challenges means that the initial burden of identifying and presenting compelling invalidity arguments against the claims lies entirely with the defendant. This also implies that if a strong IPR is filed, it would be the first such challenge and could potentially set the precedent for the patent's validity.

Inventors

• David L. Brown: No employer at the time of filing is determinable from the patent text.
• Fred S. Hirt: No employer at the time of filing is determinable from the patent text.

No unusual patterns, such as all inventors departing the original assignee within 12 months of filing, are determinable from the patent text.

Original assignee

The original assignee named on the issued patent is Proxense LLC.

Information regarding whether Proxense LLC shipped a product embodying the claims, their primary line of business, or their current operating status is not determinable solely from the provided patent text or readily available in the search results without deeper investigation into the company's history.

Assignment timeline

Based on the provided information, the only assignment recorded on the Google Patents page is the initial assignment to Proxense LLC. A search of the USPTO Patent Assignment Search database is required to reconstruct the full assignment record.

I will now search the USPTO Assignment Center for US patent 8036152.

2007-03-07 (executed) / recorded N/A (Google Patents only)

• Conveyance: Assignment of Assignors Interest
• Assignor: BROWN, DAVID L., HIRT, FRED S.
• Assignee: PROXENSE, LLC.
• Correspondent: Not specified in Google Patents record.
• Context: Original assignment from inventors to the founding entity.

A search on the USPTO Assignment Center for patent number US8036152 did not return any records beyond the initial assignment to Proxense LLC that is visible on Google Patents. This suggests that Proxense LLC remains the current assignee of record for this patent.

Proxense LLC was formally incorporated in 2005 as an LLC in Delaware. Proxense LLC states it "developed sophisticated, proprietary, proximity-based detection, authentication, and automation technology", termed "'ProxPay' technology". This technology included "biometrically based user and device authentication options, the ability to conduct biometric-verified transactions without sending or exposing the underlying biometric data or storing it anywhere except the [personal data key (PDK)], and the incorporation of a registration for maintaining or verifying the PDK".

Proxense LLC has been involved in extensive patent litigation, suing companies like Samsung, Google, Intel, Apple, and Microsoft over its biometric authentication and wireless communication patents. While Proxense LLC emphasizes its technology development and identifies its founder and CEO, John J. Giobbi, as a prolific inventor with approximately 75 patent assets in the company's possession, it is currently described as a "non-practising entity (NPE) and former operating company" focused on enforcing its patents.

Assignment timeline

• 2007-03-07 (executed) / recorded N/A (Google Patents only) — Reel N/A
  • Conveyance: Assignment of Assignors Interest
  • Assignor: BROWN, DAVID L., HIRT, FRED S.
  • Assignee: PROXENSE, LLC.
  • Correspondent: Not specified in Google Patents record.
  • Context: Original assignment from inventors to the founding entity.

No additional assignments for US8036152 were found in the USPTO Assignment Center.

Timeline diagram

timeline
    title Ownership of US 8036152
    2007 : Inventors assign to Proxense LLC
    2011 : Patent issued
    2024 : Litigation filed against Apple
    2024 : Litigation filed against Intel
    2024 : Litigation filed against LG

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The patent was assigned directly from the inventors to Proxense LLC, which was formally incorporated in 2005. While Proxense LLC is now described as a "non-practising entity," there is no evidence of a subsequent transfer to a shell entity with a name suggesting a licensing-only function.
2. Known asserter in the chain — Present. Proxense LLC is identified as a "non-practising entity (NPE) and former operating company" by ip fray and RPX Corporation.
3. Repeat correspondent across the chain — Unclear. The initial assignment from the inventors to Proxense LLC does not specify a correspondent in the Google Patents record. Without further assignment records, it's not possible to determine if the same correspondent recurs.
4. Cascading transfers — Not present. No evidence of multiple consecutive assignments was found.
5. Pre-litigation transfer — Not present. The patent was assigned to Proxense LLC in 2007. Litigation activity against Apple, Intel, and LG began in 2024. There is a significant time gap between the assignment and the commencement of litigation, so the assignment was not pre-litigation.
6. Bankruptcy fire-sale — Not present. There is no information to suggest Proxense LLC has undergone bankruptcy proceedings leading to a patent sale.
7. Privateering — Unclear. While Proxense LLC is an NPE and is asserting patents, there is no explicit information in the provided search results to indicate that an operating company transferred this patent to Proxense LLC to assert on its behalf against competitors.
8. Defensive aggregator (anti-NPE) — Not present. The patent remains with Proxense LLC, an asserting entity, and has not been transferred to a defensive aggregator.

Verdict

NPE — high confidence. Proxense LLC is explicitly identified as a "non-practising entity (NPE) and former operating company" that focuses on patent enforcement. Furthermore, there are multiple ongoing litigations against major technology companies (Apple, Intel, LG, Microsoft) where this patent is being asserted.

For verification, see the USPTO Patent Assignment Search at https://assignmentcenter.uspto.gov/ (search for patent number US8036152).

To identify the most relevant prior art for US Patent 8,036,152, I will examine the patent citations listed on the Google Patents page for US8036152. Given the large number of citations (over 300), I will focus on those that appear most pertinent to the core inventive concept of power management in a client device through system time slot assignment, as described in independent claims 1, 16, and 27. I will select a few representative U.S. patents and international publications that are likely to cover aspects of wireless communication, power management, and time slotting.

The core concepts of US8036152's independent claims are:

• Claim 1 (Apparatus): A client device with a wireless transceiver (active/sleep mode) and processing circuitry to switch modes based on received time slot assignment information.
• Claim 16 (Method): Wirelessly receiving time slot assignment, placing transceiver in sleep, and activating at the beginning of the time slot.
• Claim 27 (System): A network device broadcasting synchronization/time slot information, and a client device receiving it and entering sleep mode outside the time slot.

I will now gather details for a selection of cited prior art documents.

Selected Prior Art References and Analysis:

Here are a few representative prior art documents cited in US8036152, along with an initial assessment of their relevance:

1. US6400262B1

• Full Citation: US6400262B1, "System and method for communicating with and providing power to wireless devices," inventors Richard D. Sager, et al., assigned to Symbol Technologies, Inc.
• Publication/Filing Date: Issued: June 4, 2002; Filed: June 15, 2000.
• Brief Description: This patent describes a system and method for communicating with and providing power to wireless devices, particularly in a local area network (LAN) environment. It focuses on using a base station to provide power to transponders and to manage communication. The patent discusses communication within a defined time frame or window.
• Potential Anticipation (35 U.S.C. § 102): US6400262B1 potentially anticipates elements of claims 1, 16, and 27 relating to wireless communication with client devices and management of device activity within a system. While it discusses communication within a "time frame," the explicit mechanism of receiving time slot assignment information by the client device and switching to sleep mode outside of that assigned time slot specifically for power conservation might not be fully disclosed in the same manner as US8036152. However, the concept of a base station communicating with and managing power for wireless devices suggests some overlap, especially concerning methods for controlling when devices communicate, which indirectly relates to power. The focus on providing power to devices rather than managing internal power states based on scheduling is a distinction.

2. US6914534B2

• Full Citation: US6914534B2, "Method and apparatus for dynamic slot allocation in a wireless communication system," inventors Jukka-Pekka V. Kauppinen, et al., assigned to Nokia Corporation.
• Publication/Filing Date: Issued: July 5, 2005; Filed: November 29, 2000.
• Brief Description: This patent describes a method and apparatus for dynamic slot allocation in a wireless communication system, specifically addressing resource allocation based on different quality of service (QoS) requirements. It aims to efficiently utilize communication resources by adjusting slot allocations.
• Potential Anticipation (35 U.S.C. § 102): US6914534B2 is highly relevant as it explicitly deals with "dynamic slot allocation" in wireless communication. This patent likely anticipates elements of claims 1, 16, and 27 concerning assigning time slots for client device communication. The core difference could lie in the motivation and specific mechanism of power management. While dynamic slot allocation in US6914534B2 is for resource efficiency and QoS, US8036152 explicitly links time slot assignment to enabling a sleep mode for power conservation in the client device, and activating at the beginning of the assigned slot after a predetermined sleep. This distinction, particularly the client-side power state management based on the received assignment to enable deep sleep, might be a distinguishing feature.

3. US6944443B2

• Full Citation: US6944443B2, "Method and apparatus for power save communication in a wireless local area network," inventors Jin-Meng Wu, et al., assigned to Intel Corporation.
• Publication/Filing Date: Issued: September 13, 2005; Filed: July 31, 2002.
• Brief Description: This patent describes methods and apparatus for power-saving communication in a wireless local area network (WLAN). It discusses techniques for a wireless station to enter and exit a power save mode based on network indications, such as traffic indication maps (TIMs) within beacon frames.
• Potential Anticipation (35 U.S.C. § 102): US6944443B2 is very highly relevant as its title directly addresses "power save communication" in a wireless network. The concept of a wireless station (client device) entering a power save (sleep) mode and waking up based on network indications (like beacon frames containing traffic information, which can be interpreted as a form of time slot assignment for potential communication) directly aligns with the inventive concepts of US8036152. Specifically, it likely anticipates the apparatus (Claim 1) with active/sleep modes switched based on received information, the method (Claim 16) of receiving information for communication, placing in sleep, and activating, and the system (Claim 27) with a network device broadcasting synchronization and a client device entering sleep outside its communication time. The distinction might be in the specificity of "time slot assignment information" vs. "traffic indication maps" and whether the client device actively receives and interprets a specific individual time slot assignment for its own transmit/receive opportunities, rather than just knowing when the access point has buffered data for it. However, the overall objective and many functional elements appear to overlap significantly.

4. US6665516B2

• Full Citation: US6665516B2, "Power management in a wireless device," inventors Timothy L. Markley, et al., assigned to Intermec IP Corp.
• Publication/Filing Date: Issued: December 16, 2003; Filed: March 29, 2002.
• Brief Description: This patent describes a wireless device that manages its power consumption by operating in different power states (e.g., full power, sleep) and waking up periodically to check for network activity or receive data. It focuses on reducing power consumption in data collection terminals.
• Potential Anticipation (35 U.S.C. § 102): US6665516B2 generally addresses "power management in a wireless device," making it relevant. It likely anticipates the broad concept of a wireless client device having active and sleep modes for power conservation (Claim 1). The idea of a device waking up periodically to check for network activity also touches upon aspects of time-based activity. However, whether it specifically discloses the network assigning a precise time slot to the client device for communication, and the client device switching modes based on that explicit assignment as described in US8036152's independent claims, would require a detailed examination. The periodic wake-up without an explicit assigned time slot from the network could be a differentiating factor.

5. WO2004070549A2

• Full Citation: WO2004070549A2, "Method and apparatus for power saving in a wireless communication system," inventors Håkan H. Andersson, et al., assigned to Telefonaktiebolaget LM Ericsson (publ).
• Publication/Filing Date: Published: August 19, 2004; Filed: February 13, 2004 (PCT application PCT/SE2004/000181).
• Brief Description: This international publication describes techniques for power saving in wireless communication systems, particularly focusing on controlling a wireless terminal's sleep mode duration. It may involve receiving information about when to wake up or when data is available.
• Potential Anticipation (35 U.S.C. § 102): WO2004070549A2 is relevant due to its focus on "power saving in a wireless communication system." It likely describes a wireless terminal (client device) entering a sleep mode and waking up based on some received information from the network, which aligns with the core ideas of US8036152's claims. Similar to US6944443B2, the extent to which it explicitly discloses the network sending specific time slot assignment information that directly dictates when the client device should become active for its own communication opportunities (both transmit and receive, especially for transmitting data), and the client then remaining in sleep mode outside that precise slot, would determine its direct anticipatory effect. The general concept of power saving based on network signaling is certainly anticipated.

Summary of Anticipation:

The prior art, particularly US6944443B2 and WO2004070549A2, demonstrates that the broad concepts of power saving in wireless client devices by employing sleep modes and waking up based on network-provided information (like beacons or traffic indicators) were known prior to the filing date of US8036152. These references often describe mechanisms for client devices to know when to listen for incoming data, thereby allowing them to sleep otherwise.

The potential novelty of US8036152, in light of these references, likely lies in the specificity of the "time slot assignment information" and how it is used. US8036152 emphasizes the client device receiving information that assigns a time slot for it to wirelessly communicate data (not just listen for data addressed to it) and then activating precisely at the beginning of that assigned slot to perform that communication, and explicitly sleeping outside of it. This might suggest a more granular, client-specific scheduling for both uplink and downlink communication opportunities, rather than just a general indication of network activity or buffered data. The concept of "integrated power management... via system time slot assignment" suggests that the system actively manages and assigns specific slots to client devices for their interactions, directly enabling the client's power-saving behavior.

The following analysis addresses the obviousness of US Patent 8,036,152 under 35 U.S.C. § 103, identifying combinations of prior art references that would render its claims obvious to a person having ordinary skill in the art (PHOSITA).

Identified Prior Art References for Obviousness Analysis

Based on the "Prior art" section of the Google Patents page for US8036152, the following references are considered highly relevant:

1. US20060002360A1: Personal digital key with integrated power management (Brown et al.)
2. IEEE 802.15.4 Standard: This wireless communication standard, for Low-Rate Wireless Personal Area Networks (LR-WPANs), is explicitly referenced in US8036152 itself and would have been well-known to a PHOSITA at the time of the invention.

Rationale for Selecting References

US20060002360A1 (Brown et al.) is selected as a primary reference because its title directly addresses "Personal digital key with integrated power management," which closely aligns with the core subject matter of US8036152. This patent shares common inventors with US8036152, indicating it is highly relevant prior art.

IEEE 802.15.4 Standard is selected because US8036152 explicitly states that its system "may rely, or at least partly be based, on an IEEE 802.15.4 protocol", and mentions its use for communication and timing. This demonstrates that the inventors themselves considered this standard pertinent to their work, and a PHOSITA would undoubtedly be familiar with its mechanisms for power saving and time-slotted communication.

Motivation to Combine References

A PHOSITA, seeking to improve the power management efficiency and communication reliability of the personal digital key (PDK) described in US20060002360A1, would have been motivated to integrate the time-slotted communication and power-saving features of the widely adopted IEEE 802.15.4 standard. The primary motivation would be to further reduce power consumption in the portable client device (PDK) and to optimize wireless channel access by minimizing contention and precisely scheduling communication windows.

US20060002360A1 teaches a PDK with basic power management, where its receiver wakes up for a short period to receive a signal and then powers down, and its transmitter sends data during a "defined transmission time slot". While this implies some level of time awareness, a PHOSITA would recognize that a more explicit and dynamic assignment of time slots, as provided by IEEE 802.15.4's beacon-enabled mode and Guaranteed Time Slots (GTS), could lead to significant power savings and more efficient network operation. By receiving explicit time slot assignment information, a client device could remain in a deep sleep mode for longer, only waking precisely for its assigned communication opportunities, rather than merely "waking up for a short period" in a less predictable manner. This direct optimization of battery life and communication channel efficiency provides a clear motivation for the combination.

Obviousness Analysis of Independent Claims

Independent Claim 1 (Apparatus)

Claim Language: "An apparatus comprising: a wireless transceiver having an active mode in which power is consumed, and a sleep mode in which power is conserved; and processing circuitry operatively coupled to the wireless transceiver, where the processing circuitry is arranged to switch the wireless transceiver from the sleep mode to the active mode based on time slot assignment information received by the wireless transceiver."

Obviousness Combination: US20060002360A1 in view of the IEEE 802.15.4 Standard.

Explanation:

• "a wireless transceiver having an active mode in which power is consumed, and a sleep mode in which power is conserved;": US20060002360A1 discloses a PDK with a receiver that "wake[s] up for a short period of time to receive a signal...and then caus[es] the receiver to power down" [cite: 1, US20060002360A1 Abstract]. This clearly teaches active (wake up) and sleep (power down) modes for power management.
• "and processing circuitry operatively coupled to the wireless transceiver, where the processing circuitry is arranged to switch the wireless transceiver from the sleep mode to the active mode based on time slot assignment information received by the wireless transceiver.": US20060002360A1 further teaches "control circuitry, coupled to the receiver, that is capable of causing the receiver to wake up" [cite: 1, US20060002360A1 Claim 1]. It also mentions a transmitter capable of "transmitting data during a defined transmission time slot" [cite: 1, US20060002360A1 Claim 15]. A PHOSITA, familiar with the IEEE 802.15.4 standard (which US8036152 itself explicitly relies on), would know that in a beacon-enabled network, a device receives synchronization information in beacons. This synchronization information can include "time slot assignment information," such as the allocation of a Guaranteed Time Slot (GTS). The standard specifically enables devices to awaken from a sleep state to participate in their assigned GTS, thereby switching from sleep mode to active mode based on this received assignment. Integrating this known power-saving mechanism from IEEE 802.15.4 into the PDK of US20060002360A1 would be an obvious design choice for enhancing power efficiency.

Independent Claim 16 (Method)

Claim Language: "A method of facilitating data exchange, comprising: wirelessly receiving information assigning a time slot for a portable client device to wirelessly communicate data; placing the wireless transceiver in a sleep mode for a predetermined amount of time; and activating the wireless transceiver from the sleep mode at a beginning of the time slot."

Obviousness Combination: US20060002360A1 in view of the IEEE 802.15.4 Standard.

Explanation:

• "wirelessly receiving information assigning a time slot for a portable client device to wirelessly communicate data;": A PHOSITA combining the PDK of US20060002360A1 (a "portable client device") with the IEEE 802.15.4 standard would understand that a coordinator (like an RDC in US8036152) broadcasts beacons containing synchronization information. This information can explicitly "assign a time slot" (e.g., a GTS) for a client device to communicate data.
• "placing the wireless transceiver in a sleep mode for a predetermined amount of time;": US20060002360A1 teaches the concept of "power down" for the receiver [cite: 1, US20060002360A1 Claim 1]. The IEEE 802.15.4 standard provides specific mechanisms for devices to enter a low-power sleep mode during inactive periods of a superframe, or when not scheduled for a GTS, which constitutes a "predetermined amount of time" for power conservation.
• "and activating the wireless transceiver from the sleep mode at a beginning of the time slot.": This is a direct consequence and well-known function of devices operating under the IEEE 802.15.4 standard with assigned GTS. The device's MAC layer ensures the transceiver is "activated... at a beginning of the time slot" for its scheduled communication, having previously been in sleep mode during non-assigned periods. This improves upon the general "wake up for a short period" of US20060002360A1 by providing precise timing based on received assignments.

Independent Claim 27 (System)

Claim Language: "A system comprising: a network device arranged to wirelessly broadcast synchronization information in a wireless coverage range; and a portable client device arranged to wirelessly receive the synchronization information, where the synchronization information indicates a time slot for the client device to wirelessly communicate data, and where the client device enters a sleep mode during a time outside of the time slot."

Obviousness Combination: US20060002360A1 in view of the IEEE 802.15.4 Standard.

Explanation:

• "a network device arranged to wirelessly broadcast synchronization information in a wireless coverage range;": US20060002360A1 describes an "external reader device" that communicates wirelessly with a PDK [cite: 1, US20060002360A1 Abstract]. A PHOSITA would readily understand that such a reader device could function as a network coordinator in an IEEE 802.15.4 network, which is "arranged to wirelessly broadcast synchronization information" in the form of beacons.
• "and a portable client device arranged to wirelessly receive the synchronization information, where the synchronization information indicates a time slot for the client device to wirelessly communicate data, and where the client device enters a sleep mode during a time outside of the time slot.": US20060002360A1 describes a "personal digital key (PDK)" as a "portable client device" that can "wirelessly communicat[e] with an external reader device" [cite: 1, US20060002360A1 Abstract]. Integrating this PDK with the IEEE 802.15.4 standard means the PDK would be "arranged to wirelessly receive the synchronization information" (beacons). This received information, particularly if it includes GTS allocation, would "indicate a time slot for the client device to wirelessly communicate data". Furthermore, the fundamental power-saving principle of IEEE 802.15.4 (which US8036152 specifically mentions adopting) dictates that the client device "enters a sleep mode during a time outside of the time slot" assigned for its activity (e.g., outside its GTS or the active period). This combination represents a straightforward application of known power management techniques from a relevant standard to an existing portable wireless device.

Confirmation from Search Results for IEEE 802.15.4:

The search results confirm that the IEEE 802.15.4 protocol, especially in its beacon-enabled mode, is designed for low-rate wireless personal area networks and includes explicit power-saving mechanisms. Key aspects relevant to the obviousness analysis are:

• Beacon-enabled mode: Coordinators periodically send beacon frames to synchronize associated devices and describe the superframe structure.
• Superframe structure: A superframe can have an active period and an inactive (sleep) period. During the inactive period, devices may enter a sleep mode to save energy.
• Guaranteed Time Slots (GTS): Within the active period's Contention-Free Period (CFP), GTSs can be allocated to individual devices by the network coordinator. A device with an allocated GTS uses these slots to transmit data without contention and with guaranteed transmission.
• GTS Allocation and Management: A GTS is allocated by the PAN coordinator for communications between the coordinator and a device. The coordinator determines whether to allocate a GTS based on requests and available superframe capacity.
• Power Saving with GTS: The synchronization scheme allows nodes to wake up and sleep at the same time, enabling very low duty cycles and thus saving energy. Devices can use assigned time-slots to transmit periodically generated data without having to compete for the channel, and can remain in sleep mode when not scheduled to transmit.

These aspects directly support the obviousness arguments for all independent claims, demonstrating that the concept of receiving time slot assignment information, entering sleep mode, and activating the transceiver at the beginning of an assigned time slot for power conservation was a well-known and inherent feature of the IEEE 802.15.4 standard.