Unlicensed SCell Control Signaling Reception via Preamble Detection
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE networks, face challenges in adequately receiving control signaling when operating on unlicensed spectrum, due to regulatory requirements and the need to coexist with other wireless systems, leading to complexities in transmission and reception.
Innovation Solution
The proposed solution involves a user equipment (UE) communicating with a base station using a primary serving cell on a licensed carrier and a secondary serving cell on an unlicensed carrier, where a preamble transmission is detected and Downlink Control Information (DCI) is decoded, with specific cyclic prefix durations and blind decoding candidates managed to improve reception efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE monitors for control signaling in unlicensed spectrum subframes, then the ability to receive data on Scell is improved, but the complexity of determining transmission truncation and managing cyclic prefix durations increases
Solution Approach 1:
The base station transmits a preamble signal before the actual control signaling to indicate whether the subframe transmission will be truncated. This preliminary action allows the UE to prepare appropriate reception parameters in advance, avoiding the need for complex real-time analysis of transmission status and reducing reception processing complexity while maintaining reliable control signaling reception.
2Adaptability or versatility
If the UE uses a first cyclic prefix duration for preamble symbols and a second cyclic prefix duration for data symbols, then the ability to handle truncated transmissions is improved, but the complexity of managing multiple cyclic prefix durations increases
Solution Approach 1:
The patent applies different cyclic prefix durations to different parts of the transmission: a first cyclic prefix duration for preamble symbols and a second cyclic prefix duration for data symbols. This local differentiation allows the system to optimize for the specific requirements of each transmission phase while providing clear indicators to the UE about transmission status, thereby improving truncated transmission handling without requiring the UE to manage multiple cyclic prefix configurations simultaneously.
3Reliability
If the UE performs blind decoding of Downlink Control Information in multiple OFDM symbols, then the reliability of control information reception is improved, but the processing time and complexity increase
Solution Approach 1:
The preamble transmission provides advance information about the subframe structure and transmission status before the UE begins blind decoding operations. This allows the UE to narrow down the search space for Downlink Control Information and make more informed decisions about which OFDM symbols to decode, thereby maintaining high decoding reliability while reducing the overall processing time required.
Data Source
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AI summary
A method and apparatus provide reception of control signaling in a wireless communication network. A preamble transmission can be detected from a second device in a first set of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol starting with a first OFDM symbol in a subframe received on a secondary serving cell operating on an unlicensed carrier, the first OFDM symbol having a first Cyclic Prefix (CP). A second OFDM symbol in the subframe can be determined such that the second OFDM symbol immediately follows the first set of OFDM symbols. Downlink Control Information (DCI) containing a Physical Downlink Shared Channel (PDSCH) resource assignment can be decoded in a second set of OFDM symbols beginning with the second OFDM symbol, the second set of OFDM symbols having a second CP. The duration of the first CP is larger than the duration of the second CP.