LSA-RNTI PHY Signaling for Dynamic Spectrum Access Latency
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Solution Overview
Problem
Licensed Shared Access (LSA) systems face challenges in efficiently managing spectrum usage among multiple licensees with varying priorities, requiring effective mechanisms for detecting and protecting higher-priority users to ensure optimal Quality of Service (QoS) and spectral efficiency.
Innovation Solution
The implementation of a Physical Layer (PHY) signaling scheme using a new Radio Network Temporary Identifier (RNTI), known as LSA-RNTI, which scrambles the cyclic redundancy check (CRC) bits of Downlink Control Information (DCI) to indicate channel activation/deactivation status, allowing User Equipments (UEs) to promptly adjust their operations to protect higher-priority users, thereby minimizing latency and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional MAC layer signaling is used for channel activation/deactivation, then reliability of spectrum sharing is improved, but latency increases and spectral efficiency deteriorates
Solution Approach 1:
The patent replaces the traditional MAC layer signaling mechanism with a PHY layer signaling mechanism. Specifically, it uses Physical Downlink Control Channel (PDCCH) transmissions with Cyclic Redundancy Check (CRC) bits scrambled by a dedicated Radio Network Temporary Identifier (RNTI) to convey channel activation/deactivation commands. This substitution moves the signaling function from a higher protocol layer to the physical layer, enabling faster processing and reducing latency while maintaining reliability through the robust CRC-based acknowledgment mechanism.
Solution Approach 2:
The patent implements preliminary action by pre-configuring UEs with the LSA-RNTI and establishing the PHY layer signaling mechanism in advance. When spectrum sharing conditions change, the eNB can immediately transmit activation/deactivation commands via PDCCH without waiting for higher layer protocol procedures. This pre-configuration enables rapid response to changing spectrum conditions, reducing the time required for channel state changes while ensuring reliable delivery through the pre-established CRC verification process.
2Productivity
If PHY layer signaling is used for channel activation/deactivation, then latency is reduced and spectral efficiency is improved, but processing complexity increases
Solution Approach 1:
The patent applies universality by using the existing PDCCH infrastructure and CRC scrambling mechanism for dual purposes: traditional scheduling commands and LSA channel activation/deactivation commands. The same physical channel (PDCCH) and same reliability mechanism (CRC with RNTI) are reused for different functions. This multi-functionality approach enables PHY layer signaling for spectrum sharing without requiring entirely new signaling pathways, thereby limiting the increase in processing complexity while achieving improved spectral efficiency and reduced latency.
3Productivity
If multiple licensees share licensed spectrum with different priorities, then spectral efficiency is improved, but interference management becomes more complex
Solution Approach 1:
The patent segments the licensed spectrum into multiple Licensed Shared Access (LSA) channels or carriers, each potentially assigned to different licensees with varying priorities. The eNB can independently activate or deactivate specific LSA channels based on real-time spectrum conditions and interference levels. This segmentation allows different portions of the spectrum to be dynamically allocated to different users based on their priority levels and current usage patterns, improving overall spectral efficiency while managing interference through granular channel-level control rather than blanket spectrum management.
Data Source
AI summary
An eNB (or other base station) comprising one or more processors may generate a plurality of channel status activation indicators. The eNB's processors may encode the plurality of indicators into a Downlink Control Information (DCI) codeword, may scramble the cyclic redundancy check bits of the DCI with a predetermined sequence, and may generate the DCI codeword to the UE as part of a DCI transmission on a physical control channel. A UE (or other mobile handset) comprising one or more processors may process a DCI transmission from the eNB, the DCI transmission including a DCI codeword. The UE's processors may decode a plurality of channel status activation indicators from the DCI codeword, may check if the cyclic redundancy bits of the DCI are scrambled with a predetermined sequence, and may trigger a plurality of physical layer activation-and-deactivation circuitries based on the plurality of channel status activation indicators.