Uplink Control Resource Segmentation for Interference Cancellation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional wireless communication systems face challenges in reducing interference in heterogeneous networks, particularly from macro cells to pico/femto cells, which affects the performance and reliability of control channels.

Innovation Solution

The solution involves determining an uplink acknowledgment region associated with a macro cell and assigning uplink control resources within this region to reduce interference, using a processor to transmit control signals and implement interference cancellation techniques, such as DTX-assisted algorithms, to regenerate and decode desired control signals while canceling out interfering signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional wireless communication systems operate in heterogeneous networks with macro and pico/femto cells, then network coverage and capacity are improved, but interference from macro cells to pico/femto cells deteriorates control channel performance

Engineering Contradiction:

Improvenetwork capacityVSAvoidcontrol channel performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the uplink acknowledgment region into multiple sub-regions and assigns different pico/femto cells to different sub-regions. This spatial segmentation allows simultaneous operation of macro and pico/femto cells while reducing interference between them, thereby maintaining network capacity while improving control channel performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning specific resource regions within the uplink acknowledgment region to specific pico/femto cells based on their locations and interference characteristics. Each pico/femto cell operates with optimized local resource allocation, reducing interference from macro cells while maintaining overall network productivity.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If uplink control resources are assigned in the uplink acknowledgment region, then control signal transmission is enabled, but interference from macro cell acknowledgments deteriorates the reliability of control channel reception

Engineering Contradiction:

Improvecontrol signal transmissionVSAvoidcontrol channel reception

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent extracts interfering macro cell acknowledgment signals from the received signal by identifying and removing them through interference cancellation techniques. This allows the pico/femto cell to receive control signals with improved reliability by eliminating the extracted interference components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful interference from macro cell acknowledgments into beneficial information by using the known macro cell transmission characteristics to reconstruct and cancel the interference. The interfering signal, once identified, becomes the basis for interference cancellation, thereby improving control channel reception reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If interference cancellation techniques are implemented, then control channel reliability is improved, but system complexity increases due to additional processing requirements

Engineering Contradiction:

Improvecontrol channel reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-determining the uplink acknowledgment region and assigning specific sub-regions to different pico/femto cells before interference occurs. This proactive resource allocation reduces the complexity of real-time interference cancellation by limiting the interference to predictable patterns that can be handled with simpler processing algorithms.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by implementing interference cancellation only for the specific uplink acknowledgment region where macro cell interference is most severe, rather than applying complex cancellation techniques across the entire spectrum. This selective approach improves control channel reliability while minimizing the increase in system complexity.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8638743B2Method and apparatus that facilitates interference cancellation for control channels in heterogeneous networks

Publication Date: 2014.01.28 QUALCOMM INC

AI summary

Aspects are described for reducing interference in wireless systems. In a first embodiment, an uplink acknowledgment region associated with a macro cell is determined, and an assignment of uplink control resources is restricted to a region within the uplink acknowledgment region. A control signal is then transmitted to user equipment via the assignment of uplink control resources. In another embodiment, control signals are received from wireless terminals, which include desired uplink control signals associated with an access point base station, as well as interfering uplink acknowledgement signals associated with macro cells. The control signals may then be regenerated by cancelling the set of interfering signals from the control signals. The desired uplink control signals are then decoded.