Uplink Control Codewords With Expurgation for Bandwidth Efficiency

Solution Overview

Problem

Wireless communication systems face inefficiencies in transmitting control channel information due to bandwidth limitations and conflicting requirements, particularly in uplink control channel design using SC-FDMA or OFDMA, which struggle with spectral efficiency and interference-level estimation.

Innovation Solution

The implementation of a complex orthogonal codeword set with a subset of expurgated codewords, where undesirable codewords are discarded to meet spectral efficiency, and multi-mode operation is employed to improve bandwidth efficiency, allowing for non-coherent signaling in SC-FDMA or OFDMA systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex orthogonal modulation is used for uplink control channels, then transmission reliability is improved, but bandwidth efficiency deteriorates due to the large number of tones required

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidbandwidth consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and removes problematic codewords from the complete orthogonal codeword set that exhibit undesirable cross-correlation properties. By identifying and eliminating these specific codewords that cause interference issues, the system maintains the necessary number of codewords for reliable transmission while reducing the overall bandwidth consumption associated with handling all possible codewords.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of codeword selection by introducing cross-correlation thresholds and criteria. Instead of using all possible orthogonal codewords, the system selectively chooses codewords that meet specific cross-correlation requirements, thereby optimizing the balance between transmission reliability and bandwidth efficiency.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If all codewords are retained in the orthogonal codeword set, then codeword selection flexibility is improved, but spectral efficiency deteriorates due to inclusion of undesirable codewords

Engineering Contradiction:

Improvecodeword selection flexibilityVSAvoidspectral efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent extracts and removes problematic codewords from the complete orthogonal codeword set that exhibit undesirable cross-correlation properties. By identifying and eliminating these specific codewords that cause interference issues, the system maintains the necessary number of codewords for reliable transmission while reducing the overall bandwidth consumption associated with handling all possible codewords.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different quality standards to different codewords based on their cross-correlation properties. Instead of treating all codewords uniformly, the system evaluates each codeword's cross-correlation characteristics and selectively retains only those that meet the desired performance criteria, creating a non-uniform but optimized codeword set.

Inventive Principle:

Principle #3Local quality

3Reliability

If the complete orthogonal codeword set is used, then interference robustness is improved, but bandwidth efficiency deteriorates

Engineering Contradiction:

Improveinterference robustnessVSAvoidbandwidth usage

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and removes problematic codewords from the complete orthogonal codeword set that exhibit undesirable cross-correlation properties. By identifying and eliminating these specific codewords that cause interference issues, the system maintains the necessary number of codewords for reliable transmission while reducing the overall bandwidth consumption associated with handling all possible codewords.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potentially harmful effect of high cross-correlation between codewords into a beneficial selection criterion. By identifying codewords with undesirable cross-correlation properties and systematically excluding them, the system transforms what would be a source of interference into a guide for optimizing the codeword set, thereby improving both interference robustness and bandwidth efficiency.

Inventive Principle:

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

Data Source

PatentUS7839308B2Using codewords in a wireless communication system

Publication Date: 2010.11.23 QUALCOMM INC

AI summary

Systems, methodologies, and devices are described that can facilitate bandwidth efficient non-coherent signaling for uplink control channel transmissions. A communication device (e.g., a mobile device, base station) can be configured to utilize or generate a set of complex orthogonal codewords to facilitate transmission of control channel information using non-coherent signaling in a bandwidth efficient manner. A complex orthogonal codeword set can comprise a first subset of codewords where such codewords have a desirable cross-correlation property and another subset(s) of codewords that can include expurgated codewords, where the expurgated codewords can include discarded codewords and/or codeword pairs that produce a worst-case cross-correlation property. The codeword set and subsets are determined based at least in part on a predefined codeword criterion. A portion of the discarded codewords can be used for other purposes, such as erasure decoding, interference-level estimation, and/or multi-mode control channel operation.