Super-cell Codebook Design for Joint Processing Coordinated Multi-Point

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Solution Overview

Problem

Current coordinated multi-point transmission technologies face challenges in optimizing codebook design for joint processing, particularly in choosing between single joint multi-cell and separate codebooks, which affects Channel Quality Indicator/Precoding Matrix Indicator/Rank Indicator (CQI/PMI/RI) computation and reporting, leading to suboptimal performance due to interference considerations and computational complexities.

Innovation Solution

The method involves designing a super-cell codebook that selects a code for each combination of cooperating points and transmit antennas, using a block diagonal precoding matrix structure to accommodate both joint and disjoint CQI/PMI/RI reporting strategies, enhancing precoding diversity and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single joint multi-cell codebook is used for coordinated multi-point transmission, then the system achieves better interference coordination and homogeneous codebook structure, but the computational complexity increases and adaptability to different transmission scenarios decreases

Engineering Contradiction:

Improveinterference coordinationVSAvoidcomputational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The codebook is segmented into cell-specific codebooks for each cooperating point rather than using a single joint multi-cell codebook. Each cell maintains its own codebook structure, which reduces the overall computational complexity while still enabling coordinated multi-point transmission through selective codebook combination at the transmitter side.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically selects between using a single cell's codebook or combining multiple cell-specific codebooks based on the transmission scenario. This dynamic adaptation allows the system to adjust computational complexity according to the number of cooperating points and transmission conditions, rather than always using the most complex joint codebook structure.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If separate codebooks are used for each cooperating point, then the computational complexity and codebook design flexibility improve, but the interference coordination performance deteriorates

Engineering Contradiction:

Improvecodebook design flexibilityVSAvoidinterference coordination

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism where the UE computes CQI/PMI/RI separately for each cell using cell-specific codebooks, then the network side combines these results for joint processing. This intermediary approach maintains the flexibility of separate codebooks while achieving interference coordination through the combination process, resolving the contradiction between codebook flexibility and interference coordination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Separate cell-specific codebooks are merged or combined at the network side when generating the final precoding matrix. This combining operation enables interference coordination across multiple cells while each cell maintains its own codebook structure, thus achieving both codebook flexibility and interference coordination performance.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If joint CQI/PMI/RI computation is performed for all cooperating cells, then the interference coordination is optimized, but the computational complexity and reporting overhead increase

Engineering Contradiction:

Improveinterference coordinationVSAvoidcomputation and reporting overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The CQI/PMI/RI computation is segmented into separate computations for each cell rather than a single joint computation across all cells. Each cell computes its own CQI/PMI/RI independently using its specific codebook, which reduces the computational complexity and reporting overhead while still enabling joint processing at the network side for optimized interference coordination.

Inventive Principle:

Principle #1Segmentation

4Adaptability or versatility

If the codebook is designed to accommodate all combinations of cooperating points and transmit antennas, then the adaptability improves, but the codebook size and complexity increase

Engineering Contradiction:

Improvecodebook adaptabilityVSAvoidcodebook size

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each cell-specific codebook is designed to be universal and applicable to any number of cooperating points. The same cell-specific codebook can be used whether one cell or multiple cells are cooperating, eliminating the need for separate codebooks for each combination scenario. This universality maintains high adaptability while keeping individual codebook sizes manageable.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8204470B2Predecoding for joint processing coordinated multi-point transmission

Publication Date: 2012.06.19 TEXAS INSTRUMENTS INC

AI summary

This invention is a method of predecoding for joint processing coordinated multi-point transmission. The invention identifies for a particular transmission the cooperating point and the transmit antenna. The invention selects a code by reference to a selected one of a super-cell codebook for each combination of cooperating point and transmit antenna and a multi-cell codebook for each transmit antenna regardless of the cooperating point.