Dynamic Control Channel Search Space Allocation in Carrier Aggregation
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Solution Overview
Problem
Wireless communication systems face challenges in efficiently allocating control channels, particularly in carrier aggregation scenarios, where ambiguity and blocking can occur, leading to inefficient blind decoding and search space construction.
Innovation Solution
A method for a user equipment (UE) in a wireless communication system that receives multiple search spaces within a subframe, with each search space containing control channel candidate sets, and allocates them based on a dynamic allocation pattern that changes over time, using a carrier indicator field (CIF) to distinguish between UE-specific search spaces and concatenating search spaces according to a start point that can be hopped in units of subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple search spaces are allocated for carrier aggregation, then control channel coverage is improved, but ambiguity and blocking occur leading to inefficient blind decoding
Solution Approach 1:
The patent segments the control channel search space by introducing a carrier indicator field (CIF) that divides search spaces into UE-specific and common parts. This segmentation allows the UE to focus blind decoding efforts on specific segments rather than searching the entire search space, reducing complexity while maintaining reliable control channel allocation across multiple carriers.
Solution Approach 2:
The patent applies local quality by making the search space allocation dynamic and UE-specific. The CIF allows different UEs to have different search space configurations within the same cell, optimizing the search space for each UE's specific needs and reducing overall blind decoding complexity while maintaining high reliability.
2Ease of manufacture
If search spaces are concatenated based on a fixed start point, then allocation is simplified, but blocking occurs reducing transmission efficiency
Solution Approach 1:
The patent introduces dynamic hopping of the search space start point across different subframes. The start point is not fixed but changes according to a hopping pattern, which prevents persistent blocking on the same resources while maintaining relatively simple allocation rules. This dynamic approach improves transmission efficiency without significantly complicating the allocation mechanism.
Solution Approach 2:
The patent implements periodic hopping of the search space start point using a predefined pattern that repeats over time. This periodic action ensures that blocking is temporary and distributed across different subframes, maintaining overall system productivity while keeping the allocation rules relatively simple and predictable.
3Loss of information
If carrier indicator field is used to distinguish search spaces, then ambiguity is reduced, but overhead increases
Solution Approach 1:
The patent applies partial action by using the CIF only where necessary - specifically in the UE-specific search space portion. The common search space portion does not require CIF, reducing overall overhead. This selective use of CIF eliminates ambiguity in the critical UE-specific region while minimizing the total overhead added to the control channel.
Data Source
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AI summary
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and a device which enable a terminal to receive a control channel in a wireless communication system that uses multi-carriers, the method comprising the following steps: receiving a plurality of search space through a sub-frame, wherein each of the search spaces includes a plurality of control channel candidate sets and each of the search spaces corresponds to each of the carriers; and monitoring the control channel candidates for control channels, wherein the plurality of search spaces are connected in the resource region for the control channels according to an allocation pattern and with the starting point as the basis, and the allocation pattern changes according to time.