sCCE to sREG Mapping Function for Downlink Control Channels
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently mapping shortened resource element groups (sREGs) to shortened control channel elements (sCCEs) within a downlink control channel, particularly when the control channel spans multiple OFDM symbols, leading to resource overlap and reduced efficiency.
Innovation Solution
A method and apparatus for mapping each sCCE to a unique set of sREGs using a specific mapping function, ensuring each sREG is contained within a single OFDM symbol and allocating sREGs such that they are an integer multiple of sCCEs, thereby improving resource efficiency and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sREGs are mapped to sCCEs in a distributed sPDCCH RB set spanning multiple OFDM symbols, then resource allocation flexibility is improved, but resource overlap occurs and mapping efficiency deteriorates
Solution Approach 1:
The patent segments the mapping process by introducing a symbol index parameter to distinguish sREGs across different OFDM symbols. Each sREG is uniquely identified by combining its position within a symbol and the symbol index itself, preventing overlap between sREGs in different symbols while maintaining flexible resource allocation across the distributed RB set.
Solution Approach 2:
The patent adds a temporal dimension (OFDM symbol index) to the resource element mapping scheme. By incorporating the symbol index into the sREG identification and mapping process, the system extends the mapping from a two-dimensional frequency grid to a three-dimensional space including time, thereby eliminating overlap while preserving allocation flexibility.
2Productivity
If sREGs are mapped across multiple OFDM symbols, then resource utilization is improved, but decoding latency increases as waiting for subsequent symbols is required
Solution Approach 1:
The patent applies preliminary action by ensuring that all sREGs required for a given sCCE are mapped within the same OFDM symbol when possible. This allows the UE to decode control information without waiting for subsequent symbols, reducing latency while still enabling flexible resource utilization across multiple symbols when needed.
Solution Approach 2:
The patent introduces dynamic mapping behavior where the mapping strategy adapts based on the specific configuration. The system can dynamically choose to concentrate sREGs within a single symbol to minimize latency, or distribute them across multiple symbols to maximize resource utilization, depending on the operational requirements and available resources.
3Manufacturing precision
If a unique mapping function is designed to prevent sREG overlap, then mapping precision is improved, but system complexity increases
Solution Approach 1:
The patent achieves precise mapping by changing the parameters used in the mapping function to include the OFDM symbol index. This additional parameter allows the system to distinguish between sREGs in different symbols, eliminating overlap while maintaining a relatively simple mapping function that builds upon existing mapping mechanisms rather than introducing entirely new complexity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A transmitting node, such as a base station, may transmit downlink control information (DCI) to a user equipment (UE) using a number of shortened control channel elements (sCCEs). Each sCCE may consist of a number of shortened resource element groups (sREGs). The base station may map each sCCE to one or more sREGs using a mapping function to ensure that each sCCE is mapped to a unique set of sREGs (e.g., no single sREG is allocated to more than one sCCE). Use of the mapping function may further ensure that each sREG mapped to an sCCE is within a single symbol. The transmitting node may also configure a set of resource blocks (RBs) corresponding to the sREGs such that the number of RBs per symbol is an integer multiple of the number of sREGs per sCCE.