EP2525515B1 and 5 Related Patents in Carrier Aggregation Systems

Carrier aggregation may sound technical, but it is at the core of next-generation wireless performance. In simple terms, carrier aggregation means combining several smaller frequency bands into one larger channel, giving users faster and more reliable connections. Patent EP2525515B1 takes this concept a step further.

This European patent describes a smarter way for mobile devices to communicate to the network. Instead of sending feedback signals in one fixed pattern, it uses different timing shifts across the uplink, making the signals clearer and more reliable. It also explains how phones confirm whether data was received correctly, using special channels linked to the original transmissions.

While EP2525515B1 is currently in an infringement action between Sol IP and BYD Automotive GmbH, this article focuses strictly on the invention itself.

With the Global Patent Search (GPS) tool, we review similar patents and explore how other technologies handle carrier aggregation and control data transmission. GPS streamlines the search process by highlighting structural overlaps.

If you are exploring wireless system enhancements or carrier-based protocols, this GPS-driven review outlines the core ideas behind EP2525515B1 and reveals closely related patents.

Understanding Patent EP2525515B1

EP2525515B1 focuses on a wireless communication system that employs carrier aggregation (CA) to improve the transmission of control information. It describes how a terminal transmits ACK/NACK signals using two cyclically shifted slots in a subframe. The system also includes mechanisms for mapping downlink control elements to corresponding uplink channel resources.

Source: Google Patents

Its Four Key Features Are

#1. Cyclic shift variation – The terminal transmits a subframe with a first and second slot using different cyclic shifts.

#2. Uplink resource mapping – Uplink channels are selected based on the index of downlink control elements.

#3. Efficient ACK/NACK transmission – The system supports reliable feedback transmission across multiple carriers.

#4. Component carrier coordination – Communication occurs over multiple configured component carriers with role-specific functions.

This patent introduces a refined approach to uplink feedback and control signaling in multi-carrier wireless systems. It supports more efficient spectrum usage in high-demand communication environments.

Carrier aggregation boosts throughput, but it hinges on efficient discovery across fragmented bands. Please read EP3016464B1 and 5 Patents Shaping Signal Discovery in Mobile Networks to understand measurement patterns that shrink inter-frequency gaps.

Similar Patents As EP2525515B1

To explore the innovation landscape surrounding EP2525515B1, we ran the patent through the Global Patent Search tool. This surfaced related patents that share technical similarities in carrier aggregation and uplink control signaling in multi-carrier systems.

Below, we highlight five of these references that reflect comparable ideas in uplink channel management and ACK/NACK signaling.

#1. US2012213187A1

This U.S. patent, US2012213187A1, published in 2012 by LG Electronics, describes a method and apparatus for transmitting uplink control information in a multi-carrier wireless system. The invention focuses on how user equipment can send multiple ACK/NACK responses and channel state information using shared uplink resources without sacrificing signal clarity or control efficiency.

Source: GPS

What This Patent Introduces To The Landscape

1. Unified feedback over a single resource – Enables simultaneous transmission of ACK/NACK and channel state information using the same uplink control channel.
   
2. Fallback logic for overlapping signals – If ACK/NACK and CQI conflict in the same subframe, CQI is dropped to prioritize feedback integrity.
   
3. Multi-bit ACK/NACK encoding – Uses coding techniques like Reed-Muller or TBCC to compress and transmit multiple ACK/NACK bits efficiently.
   
4. Explicit PUCCH resource mapping – Introduces a method for assigning feedback channels through higher-layer signaling rather than relying solely on implicit mapping.
   
5. Embedded signaling for SR and CQI – Describes methods to embed scheduling requests or ACK/NACK directly into reference signal symbols without disrupting CQI.
   

How It Connects To EP2525515B1

• Both patents focus on efficient uplink signaling for ACK/NACK in multi-carrier environments.
  
• Each introduces mapping logic to tie downlink control elements to corresponding uplink channels.
  
• Both address control channel design in the context of carrier aggregation and uplink feedback performance.

Why This Matters

This reference confirms the early design challenges and strategies for multi-carrier uplink feedback in LTE-Advanced systems. It demonstrates how ACK/NACK multiplexing and resource sharing were foundational ideas; concepts that EP2525515B1 builds on with enhanced uplink mapping and signal coordination.

#2. US2012093097A1

This U.S. patent, US2012093097A1, published in 2012, describes a method for optimizing uplink control signaling in extended bandwidth systems using carrier aggregation. It outlines techniques for bundling ACK/NACK responses, managing asymmetric UL/DL allocations, and compressing control signaling to preserve single-carrier properties and reduce signaling overhead.

Source: GPS

What This Patent Introduces To The Landscape

1. Single-resource uplink control signaling – Enables control signals to be transmitted on a single uplink frequency chunk when shared channels are unavailable.
   
2. ACK/NACK bundling across carriers – Combines multiple feedback signals into a unified transmission for better uplink coverage.
   
3. Constellation point optimization – Uses PUCCH constellation points to efficiently carry multi-bit feedback.
   
4. Control element flexibility – Assigns multiple control channel elements per PDCCH to expand ACK/NACK signaling capabilities.
   
5. Support for asymmetric UL/DL allocations – Ensures control signaling works even when uplink and downlink resources are mismatched.
   
6. Many-to-one ACK/NACK compression – Maps multiple bits into fewer transmission states to reduce signaling complexity.
   
7. Minimized cubic metric (CM) – Encourages efficient transmission by maintaining single-carrier waveform characteristics.

How It Connects To EP2525515B1

• Both address efficient transmission of multiple ACK/NACK signals in a multi-carrier system.
  
• Each improves uplink control signaling under LTE-A using bundling and resource mapping strategies.
  
• Both prioritize maintaining single-carrier properties to support robust and power-efficient communication.

Why This Matters

This reference confirms the early design challenges and strategies for multi-carrier uplink feedback in LTE-Advanced systems. It demonstrates how ACK/NACK multiplexing and resource sharing were foundational ideas; concepts that EP2525515B1 builds on with enhanced uplink mapping and signal coordination.

#3. KR20110066833A

This Korean patent, KR20110066833A, published in 2011, describes a method and apparatus for transmitting ACK/NACK signals in wireless communication systems that support carrier aggregation. It proposes techniques for managing uplink control signaling when the number of uplink and downlink component carriers differ. It ensures efficient signal multiplexing and resource coordination across different PUCCH formats.

Source: GPS

What This Patent Introduces To The Landscape

1. Carrier-aware ACK/NACK transmission – Ensures ACK/NACK delivery even when uplink and downlink carriers are asymmetrically allocated.
   
2. PUCCH multiplexing via cyclic shifts and Walsh/DFT codes – Allows up to 18 UEs to be multiplexed in the same resource block by using orthogonal sequences.
   
3. Dynamic versus persistent scheduling support – Supports both implicit and explicit ACK/NACK resource allocation for different scheduling types.
   
4. Extended prefix format adaptation – Provides separate handling for normal and extended cyclic prefixes in PUCCH format 1a/1b transmissions.
   
5. ACK/NACK bundling and conflict resolution – Introduces bundling mechanisms and conflict handling for PHICH resources under asymmetric aggregation.
   
6. Symbol-level frequency hopping and interference randomization – Applies symbol-level cyclic shift hopping to mitigate inter-cell interference in uplink control.
   
7. Cross-carrier scheduling considerations – Enables flexible scheduling and PDCCH/PDSCH mapping across component carriers in multi-carrier systems.

How It Connects To EP2525515B1

• Both patents address uplink feedback transmission in environments where carrier aggregation creates asymmetries.
  
• Each introduces mechanisms for resource-efficient ACK/NACK signaling under component carrier mismatches.
  
• Both highlight the importance of preserving signal quality and minimizing interference in multi-carrier uplink designs.

Why This Matters

This reference further clarifies the technical constraints and control signal designs necessary for reliable ACK/NACK feedback in multi-carrier systems. It highlights methods for multiplexing, signal spreading, and scheduling that laid the groundwork for more refined uplink feedback schemes like those in EP2525515B1. Comparable innovations in beamforming and handover strategies also aim to strengthen reliability by improving signal direction and mobility management.

#4. US2012134333A1

This U.S. patent, US2012134333A1, published in 2012, describes a terminal device and retransmission control method designed to improve ACK/NACK feedback under carrier aggregation. It introduces rules for mapping response signals to PUCCH resources and phase points, enabling efficient retransmission control while managing asymmetric uplink and downlink carrier assignments.

Source: GPS

What This Patent Introduces To The Landscape

1. Blind decoding of downlink control information – Defines how terminals identify PDCCH control signals by CRC demasking against terminal IDs.
   
2. DTX handling for failed control reception – Establishes discontinuous transmission states when downlink assignment information is not successfully decoded.
   
3. PUCCH resource mapping based on CCEs – Associates PUCCH transmission resources with control channel elements, ensuring efficient feedback signaling.
   
4. Channel selection for multi-band ACK/NACK – Uses different phase points and resources to reflect varying ACK/NACK outcomes across aggregated downlink bands.
   
5. Transmission rule tables – Introduces rule sets for one, two, or three downlink component bands, linking error detection patterns to PUCCH resources and modulation.
   
6. Retransmission interpretation rules – Provides base station logic to interpret ambiguous ACK/NACK/DTX phase points for robust retransmission.
   
7. Support for asymmetric and symmetric carrier aggregation – Covers both aggregation modes, allowing flexible deployment of control signaling.
   
8. Bundled ACK approach – Groups ACK/NACK results for paired downlink bands to reduce signaling overhead while maintaining reliability.
   
9. Advanced spreading sequences – Employs ZAC, Walsh, DFT, or alternative sequences for multiplexing uplink response signals.

How It Connects To EP2525515B1

• Both patents address uplink ACK/NACK signaling challenges in multi-carrier LTE-Advanced systems.
  
• Each develops mapping and multiplexing techniques that balance efficiency and robustness under asymmetric carrier aggregation.
  
• Both emphasize minimizing control overhead while ensuring reliable feedback across aggregated carriers.

Why This Matters

This reference highlights a critical dimension of LTE-A feedback control: how terminals manage ACK/NACK transmission rules and how base stations interpret them for retransmission. By introducing structured rule tables, bundled ACKs, and channel selection methods, it reflects the complexity of uplink control in carrier aggregation. These insights form an important precursor to EP2525515B1, which builds on such schemes with enhanced uplink mapping and coordination.

#5. US2010098012A1

This U.S. patent, US2010098012A1, published in 2010, describes uplink control information (UCI) transmission methods for LTE-Advanced systems supporting carrier aggregation. It outlines techniques for handling high-volume feedback such as CQI, PMI, RI, ACK/NACK, SR, and CSI, while ensuring low peak-to-average power ratio (PAPR) and efficient multiplexing across uplink channels.

Source: GPS

What This Patent Introduces To The Landscape

1. Support for flexible carrier aggregation – Enables both symmetric and asymmetric uplink/downlink carrier configurations with scalable bandwidth.
   
2. Low-PAPR PUCCH design – Introduces spreading and mapping strategies to reduce cubic metric and maintain uplink efficiency.
   
3. Joint and separate coding of UCI – Proposes coding schemes for control data across multiple carriers, balancing robustness and efficiency.
   
4. Advanced spreading and cyclic shift schemes – Uses CAZAC, Walsh, and DFT codes with adaptive cyclic shifts to maintain orthogonality and multiplex feedback.
   
5. Multi-carrier PUCCH mapping – Defines methods for transmitting control information on one or multiple uplink carriers, including hopping for frequency diversity.
   
6. Bundled ACK/NACK feedback – Reduces overhead by combining multiple ACK/NACK bits across carriers or codewords into fewer uplink symbols.
   
7. Periodic PUSCH reporting – Introduces semi-static and dynamic periodic uplink data channel reporting modes for high-volume feedback.
   
8. Collision resolution mechanisms – Provides procedures for handling conflicts between HARQ-ACK, CQI, SR, and PUSCH transmissions.
   
9. Simultaneous PUCCH and PUSCH operation – Supports concurrent transmission of control and data channels to optimize resource use in LTE-A.
   
10. Backward compatibility with LTE Release 8 – Ensures interoperability by defining anchor and non-anchor carriers and maintaining legacy signaling formats.

How It Connects To EP2525515B1

• Both patents address uplink signaling challenges in carrier aggregation, focusing on how control data and ACK/NACK feedback are transmitted reliably.
  
• Each emphasizes efficient multiplexing of feedback information while keeping overhead low.
  
• Both reflect strategies for supporting asymmetric aggregation and managing simultaneous uplink control channels.

Why This Matters

This reference illustrates how LTE-Advanced anticipated the surge in uplink feedback due to multi-carrier operation and high-order MIMO. By proposing bundled ACK/NACK schemes, flexible coding, and periodic PUSCH reporting, it set the stage for managing high-volume control signaling. These innovations directly inform the context of EP2525515B1, which develops enhanced uplink mapping and coordination techniques to refine and extend these approaches.

How to Find Related Patents Using Global Patent Search

Understanding the broader patent landscape is essential when exploring LTE-Advanced technologies, uplink control signaling, or carrier aggregation strategies. The Global Patent Search tool makes this easier by surfacing inventions that tackle similar challenges in uplink feedback, ACK/NACK multiplexing, and resource coordination.

1. Enter the patent number into GPS: Start by entering a patent number like EP2525515B1 into the GPS tool. The platform transforms it into a targeted query, which can be refined with terms like “uplink feedback,” “carrier aggregation,” or “ACK/NACK signaling.”

Source: GPS

2. Explore conceptual snippets: Instead of comparing features claim-by-claim, GPS now presents curated text snippets. These highlight how other inventions handle uplink multiplexing, resource sharing, or error feedback across multiple carriers.

3. Identify related inventions: The tool reveals patents addressing asymmetric carrier aggregation, uplink mapping strategies, and efficient feedback schemes, offering insight into how similar communication challenges have been solved. Related network congestion management methods also show how operators balance traffic loads to maintain efficiency across multiple carriers.

4. Compare systems, not legal claims: Rather than focusing strictly on legal claim language, GPS emphasizes conceptual approaches. This helps users recognize overlaps in strategies for improving uplink reliability and efficiency in LTE-Advanced.

5. Accelerate cross-domain insights: Whether working in radio resource management, PHY/MAC design, or broader 5G innovation, GPS lets researchers uncover related approaches across domains that might otherwise remain disconnected, including early groundwork for uplink signaling in next-generation networks.

With Global Patent Search, researchers can track how ideas in wireless systems evolve, from early LTE designs to emerging 5G and 6G concepts. This makes it easier to spot technical trends, anticipate future standards, and position innovations within a fast-changing communication landscape.

Disclaimer: The information provided in this article is for informational purposes only and should not be considered legal advice. The related patent references mentioned are preliminary results from the Global Patent Search tool and do not guarantee legal significance. For a comprehensive related patent analysis, we recommend conducting a detailed search using GPS or consulting a patent attorney.