LTE Control Channel Search Space Segmentation for Uplink Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The limitation of the common search space in LTE systems, associated with cell-specific reference signals, hinders efficient notification of control information, leading to reduced transmission efficiency between base stations and terminals.
Innovation Solution
The proposed solution involves enhancing the communication system by allowing the base station and terminal to communicate more efficiently through techniques such as carrier aggregation, using both Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems, and by optimizing the mapping of control channels and reference signals to improve the transmission efficiency, particularly by expanding the search spaces for control information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common search space is limited to subframes with cell-specific reference signals, then the reference signal association is maintained, but the transmission efficiency of control information deteriorates
Solution Approach 1:
The patent segments the search space into two distinct types: common search space (CSS) for control information requiring cell-specific reference signal association, and UE-specific search space (USS) for control information that can use UE-specific reference signals. This segmentation allows each search space type to use its appropriate reference signal, resolving the contradiction between maintaining reference signal association and improving transmission efficiency.
Solution Approach 2:
The patent introduces a new dimension by allowing control information to be transmitted in uplink subframes through the USS, breaking the traditional constraint that control channels can only be mapped to downlink subframes. This dimensional expansion enables more flexible control information transmission and improves overall system efficiency.
2Stability of the object's composition
If control channels are mapped only to downlink subframes, then the traditional LTE structure is maintained, but the flexibility and efficiency of control information transmission is reduced
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the search space configuration to change based on the subframe type and reference signal availability. Control information can be dynamically mapped to appropriate search spaces in both downlink and uplink subframes, enabling the system to adapt to different transmission scenarios while maintaining backward compatibility with traditional LTE structures.
3Productivity
If UE-specific reference signals are used for EPDCCH, then transmission efficiency improves, but compatibility with traditional PDCCH mechanisms is reduced
Solution Approach 1:
The patent creates a universal control channel framework where both PDCCH and EPDCCH can coexist and serve different purposes. The EPDCCH using UE-specific reference signals provides enhanced efficiency for UE-specific control information, while the PDCCH maintains traditional functionality for common control information. This multi-functionality approach allows the system to leverage the strengths of both control channel types without requiring complete redesign.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A terminal communicates with a base station and includes a transmission unit that transmits a physical uplink control channel by using a physical uplink control channel resource for transmitting HARQ-ACK in a subframe n. The physical uplink control channel resource is given by at least a value of a first control channel element used for transmitting a corresponding physical downlink control channel or a corresponding extended physical downlink control channel, in a subframe n-k. The physical uplink control channel resource is given by a first arithmetic operation when a value of the element k is the same as a value of an element in a first set. The physical uplink control channel resource is given by a second arithmetic operation when a value of the element k is the same as a value of an element in a second set.