LAA Uplink PDCCH Subframe Configuration for Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication systems face limitations in communication flexibility and efficiency, particularly in uplink Licensed-Assisted Access (LAA) operations, where the detailed design of uplink transmission procedures for LAA carriers has not been adequately defined, leading to inefficiencies in channel access and data transmission.
Innovation Solution
The implementation of systems and methods that include specific configurations for user equipment (UE) and evolved NodeBs (eNBs) to manage uplink LAA operations, utilizing PDCCHs with CRC scrambled by CC-RNTI, and DCI formats for scheduling PUSCHs, along with LBT schemes and subframe structures to optimize channel access and data transmission in unlicensed spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional communication structures are used, then system simplicity is maintained, but communication flexibility and efficiency are limited
Solution Approach 1:
The patent implements dynamic TDD- FDD switching capability where the base station can flexibly change transmission directions and frame structures based on real-time channel conditions and traffic requirements. This allows the system to adapt between time-division duplexing and frequency-division duplexing modes, enhancing communication efficiency without requiring completely separate static structures for each mode
Solution Approach 2:
The patent employs adjustable frame structure parameters including configurable subframe lengths, flexible slot structures, and dynamic resource block allocations. These parameter changes enable the system to optimize communication efficiency for different service types and channel conditions while maintaining a unified underlying communication framework
2Speed
If communication capacity and speed are improved, then service quality is enhanced, but system complexity and coordination requirements increase
Solution Approach 1:
The patent implements advance synchronization mechanisms where the base station pre-configures frame structures, resource allocations, and switching timelines before actual TDD-FDD transitions occur. This preliminary setup reduces real-time coordination complexity while enabling high-speed communication by having synchronization protocols and resource mappings prepared in advance
Solution Approach 2:
The patent incorporates continuous feedback loops where the base station monitors channel conditions, interference levels, and traffic patterns, then adjusts frame structures and switching decisions accordingly. This feedback mechanism maintains synchronization accuracy and communication speed by adapting to changing conditions without requiring complete reconfiguration
3Quantity of substance
If unlicensed spectrum is used for LAA operations, then spectrum availability is increased, but channel access reliability becomes challenging
Solution Approach 1:
The patent divides unlicensed spectrum access into structured time segments with clear Listen-Before-Talk (LBT) procedures, contention access periods, and dedicated transmission windows. This segmentation provides predictable access patterns and reliable transmission opportunities while utilizing the abundant unlicensed spectrum resources
Solution Approach 2:
The patent introduces a standardized LAA protocol layer as an intermediary between the physical channel and higher-layer applications. This protocol layer implements统一的 channel access procedures, interference management, and coordination mechanisms that ensure reliable access to unlicensed spectrum while maintaining compatibility with existing licensed network infrastructure
Data Source
AI summary
A UE is described that includes a higher layer processor configured to receive a dedicated RRC configuration message which configures a License Assisted Access (LAA) cell. The UE also includes a PDCCH receiver configured to receive a first PDCCH and a second PDCCH. The first PDCCH is a PDCCH with CRC scrambled by CC-RNTI, and with a DCI format which contains a subframe configuration field. The second PDCCH is a PDCCH with DCI formats for scheduling physical uplink shared channel(s) (PUSCH(s)) on the LAA cell. If the first PDCCH is detected in subframe n, and the first PDCCH is not detected in subframe n−1, and if the number of occupied OFDM symbols for the subframe n indicated by the subframe configuration field in the subframe n is less than 14, the UE is not required to receive any other physical channels in subframe n except for the second PDCCH.