Hierarchical Precoding Codebooks for Heterogeneous Network Coordination
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Solution Overview
Problem
Conventional wireless cellular networks lack a suitable definition of precoding codebooks for distributed antenna systems (DAS) and heterogeneous networks, which hinders effective coordination and interference management between transmission nodes, leading to reduced throughput and coverage in heterogeneous environments.
Innovation Solution
The implementation of generic hierarchical precoding codebooks in a base band unit (BBU) of a transmission node cluster, where each codebook comprises cluster precoding matrices constructed from active transmission nodes, allowing for adaptable precoding across different spatial layers and time slots, and coordinated signal quality metric-based selection of precoding matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional precoding codebooks are used in heterogeneous networks, then device complexity is reduced, but throughput and coverage are degraded due to lack of suitable definition for DAS and heterogeneous networks
Solution Approach 1:
The precoding codebook is segmented into multiple hierarchical levels: a first codebook containing first precoding matrices and a second codebook containing second precoding matrices. This segmentation allows the system to handle heterogeneous network configurations by selecting appropriate codebooks for different transmission scenarios, thereby improving throughput without overwhelming device complexity with a single monolithic codebook structure.
Solution Approach 2:
The patent introduces a hierarchical dimension to the codebook structure, organizing precoding matrices across multiple levels (first codebook and second codebook) rather than using a flat single-level structure. This dimensional organization enables efficient management of diverse precoding options for DAS and heterogeneous networks, resolving the contradiction between comprehensive throughput optimization and manageable codebook complexity.
2Productivity
If generic hierarchical precoding codebooks are implemented, then throughput and coverage are enhanced, but feedback requirements and processing complexity increase
Solution Approach 1:
The hierarchical codebook structure segments the feedback process into multiple stages: selecting a first precoding matrix from the first codebook and optionally a second precoding matrix from the second codebook. This segmentation reduces feedback complexity by breaking down the single complex selection into manageable steps, maintaining system-level performance while reducing information loss.
Solution Approach 2:
The patent implements optional feedback mechanisms where the UE can provide feedback for the first precoding matrix, and optionally for the second precoding matrix depending on configuration and channel conditions. This partial action approach allows the system to achieve high performance when needed while reducing feedback overhead in simpler scenarios, effectively managing the trade-off between performance and feedback complexity.
3Reliability
If coordinated signal quality metric-based selection is used, then link performance is improved, but processing time and computational load increase
Solution Approach 1:
The base station pre-configures the hierarchical codebooks with multiple precoding matrices organized by signal quality metrics before actual transmission occurs. This preliminary action allows the UE to efficiently select appropriate precoding matrices based on current channel conditions without performing complex real-time calculations, thereby improving link performance while minimizing processing time during active transmission.
Solution Approach 2:
The system implements selective signal quality metric evaluation where the UE assesses metrics for the first precoding matrix and conditionally evaluates the second precoding matrix based on configuration and channel conditions. This partial evaluation approach maintains high link performance when needed while reducing computational load and selection time in scenarios where full evaluation is unnecessary.
Data Source
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AI summary
A base band unit, BBU, in a wireless cellular heterogeneous network, the BBU being provided in a transmission node cluster, TNC, of transmission nodes, TNs, of neighbouring cells of the wireless cellular heterogeneous network, wherein the BBU comprises generic hierarchical precoding codebooks, CBs, each CB comprising cluster precoding matrices, CPMs, and each CPM is provided for a possible combination of active TNs within the TNC.