Dynamic Precoding Codebook Bitmap Signaling in LTE
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Solution Overview
Problem
Current telecommunications systems, particularly in LTE networks, face challenges with codebook subset restriction mechanisms, where once the bitmap is sent to the UE, there is no mechanism for the RNC to change it, limiting system performance and link adaptation.
Innovation Solution
Introducing new signaling between the NodeB and RNC to dynamically change the precoding codebook bitmap, allowing for improved link adaptation and reduced complexity at the wireless terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the precoding codebook bitmap is sent to the UE using existing mechanisms, then the initial codebook configuration is established, but the RNC cannot change it dynamically, limiting system performance and link adaptation
Solution Approach 1:
The patent introduces dynamic change capability for the precoding codebook bitmap by enabling the RNC to modify the bitmap during operation through new signaling mechanisms (RRC connection reconfiguration or dedicated physical downlink control format indicators), transforming the static bitmap into a dynamically adjustable parameter that adapts to changing channel conditions
Solution Approach 2:
The patent enables modification of the precoding codebook bitmap parameter itself, allowing the RNC to change the codebook configuration sent to the UE. This parameter change capability is achieved through introducing new signaling messages that carry updated bitmap values, enabling the system to adapt link parameters dynamically
2Productivity
If new signaling is introduced between NodeB and RNC to dynamically change the bitmap, then link adaptation is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent leverages existing signaling infrastructure (RRC connection reconfiguration messages and dedicated physical downlink control format indicators) to carry the dynamic bitmap change information, making these existing signaling mechanisms serve multiple functions - both their original purposes and the new codebook update function - thereby avoiding the need for completely new dedicated signaling channels
Solution Approach 2:
The patent transmits the precoding codebook bitmap information by copying it into existing signaling message structures (RRC connection reconfiguration or uplink dedicated physical downlink control format indicator messages), rather than creating separate new signaling protocols. This approach reuses established message formats to carry additional functionality
Data Source
AI summary
A base station node communicates over a radio interface with a wireless terminal. The base station node comprises a controller which, upon basis of channel feedback received from the wireless terminal, is configured to make a precoding codebook bitmap decision regarding a precoding codebook bitmap affecting transmissions between the base station and the wireless terminal. The base station is further configured to communicate the precoding codebook bitmap decision so that the precoding codebook bitmap decision may be implemented by the wireless terminal. In example embodiments and modes the base station sends the precoding codebook bitmap decision using a bitmap decision signal to a radio network controller.