Evolved Downlink Transmission Format for Energy-Efficient Wireless Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cellular networks face challenges in energy efficiency and spectral efficiency due to the constant transmission of control channels and cell-specific reference signals, even when there are no user equipment (UE) being served in the cell.
Innovation Solution
The introduction of an evolved downlink transmission format that eliminates legacy downlink cell-specific reference signals and control channels, allowing for reduced-density CRS transmission and the use of demodulation reference signals (DMRS) for data demodulation, thereby enabling energy savings and increased spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If legacy downlink cell-specific reference signals and control channels are transmitted continuously, then coverage and basic communication functionality are maintained, but energy consumption increases significantly and spectral efficiency decreases
Solution Approach 1:
The patent implements discontinuous transmission of control channels and reference signals by transmitting them only in periodic intervals when needed, rather than continuously. This allows the base station to enter low-power states during idle periods while maintaining communication coverage through periodic reactivation, directly resolving the contradiction between energy savings and reliability.
Solution Approach 2:
The patent extracts and removes legacy control channels and cell-specific reference signals from continuous transmission, keeping only essential transmissions. By taking out the non-essential components that consume energy, the system achieves significant power savings while retaining the core communication functionality through UE-specific reference signals and on-demand control channel transmission.
2Productivity
If control channels and reference signals are transmitted at full density, then demodulation accuracy and signal reliability are maintained, but spectral efficiency and data transmission capacity are reduced
Solution Approach 1:
The patent applies local quality by transmitting reference signals only where and when needed for specific UE data transmissions, rather than uniformly across all resources. UE-specific reference signals are placed locally in time-frequency resources corresponding to actual data transmissions, optimizing spectral efficiency while maintaining demodulation accuracy for active users.
Solution Approach 2:
The patent changes the transmission parameters of reference signals from continuous full-density transmission to dynamic, UE-specific transmission with adjusted density. By modifying transmission parameters such as time-frequency resource allocation and signal density based on actual traffic conditions, the system achieves higher spectral efficiency while preserving necessary demodulation performance.
3Adaptability or versatility
If base station transmits control channels in all subframes, then scheduling flexibility and control functionality are maintained, but energy consumption and resource waste increase in lightly loaded cells
Solution Approach 1:
The patent introduces dynamic control channel transmission where the base station adapts control channel presence and density based on real-time traffic conditions and UE requirements. In lightly loaded cells, control channels are transmitted only when necessary, while in heavily loaded cells, more frequent transmission maintains scheduling flexibility. This dynamic approach resolves the contradiction between adaptability and energy loss.
Data Source
AI summary
A method for time multiplexing subframes on a serving cell to a user equipment, wherein one set of subframes operate with the legacy LTE transmission format and one set of subframes operate with an evolved transmission format comprising reduced density CRS transmission without a PDCCH control region.