Carrier Aggregation in Shared Spectrum with Interference Avoidance
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Solution Overview
Problem
Current LTE-Advanced technologies do not specify operation of Carrier Aggregation (CA) in spectrum sharing environments, leading to potential interference with incumbent users and inefficient use of shared radio spectrum.
Innovation Solution
A system and method that establish a primary cell (PCell) in exclusively licensed spectrum and secondary cells (SCells) in shared spectrum, using schedule data to avoid interference with incumbent users by dynamically reconfiguring SCell frequency bands and disabling unused SCells, allowing for efficient use of shared spectrum while minimizing disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Carrier Aggregation is implemented in shared spectrum without coordination, then spectrum utilization efficiency is improved, but interference with incumbent users increases
Solution Approach 1:
A coordination entity is introduced as an intermediary between the LTE network and incumbent users. This entity receives schedule data from incumbents, determines available time-frequency resources, and coordinates SCell scheduling to avoid interference while enabling efficient spectrum sharing
Solution Approach 2:
The system dynamically adapts SCell configurations based on real-time spectrum availability. SCells are dynamically added, removed, activated, or deactivated according to incumbent user activity patterns, allowing the network to optimize spectrum utilization while preventing interference
2Quantity of substance
If SCells are continuously active in shared spectrum, then bandwidth availability is improved, but interference with incumbent users increases
Solution Approach 1:
SCells are activated and deactivated periodically based on incumbent user activity patterns. The coordination entity schedules SCell transmissions during time periods when incumbent users are not transmitting, creating a periodic on-off pattern that ensures bandwidth availability when spectrum is free while preventing continuous interference
Solution Approach 2:
The system uses multiple SCells that can be selectively activated. Instead of keeping all SCells continuously active, only the necessary subset is activated at any given time based on traffic demand and spectrum availability, providing partial action that balances bandwidth needs with interference avoidance
3Object-affected harmful factors
If dynamic reconfiguration of SCell frequency bands is implemented, then interference avoidance is improved, but system complexity increases
Solution Approach 1:
The coordination entity centralizes the complex task of frequency band selection and SCell reconfiguration. By offloading this functionality to a dedicated intermediary, the complexity is isolated to a single entity that manages spectrum coordination, while base stations and UEs benefit from simplified operations
Solution Approach 2:
The coordination entity receives schedule data from incumbent users in advance and pre-determines available frequency bands before SCell activation. This preliminary planning allows dynamic reconfiguration to occur smoothly without real-time complex calculations during active transmissions
Data Source
AI summary
A method for performing Carrier Aggregation (CA) using spectrum shared between an incumbent user and a telecommunications network includes establishing a primary cell (PCell) for the secondary user in a portion of radio spectrum that is exclusively licensed to the telecommunications network, establishing a secondary cell (SCell) for the telecommunications network in a portion of the shared spectrum that is shared with the incumbent user, receiving schedule data for the incumbent user at a controller in communication with the incumbent user and a transmitter for the PCell and the SCell, scheduling transmissions for the PCell and the SCell to avoid interference to the incumbent user, and transmitting the scheduled transmissions through the PCell and the SCell using Carrier Aggregation (CA). Accordingly, one or more SCell in shared spectrum may be aggregated with a PCell in dedicated spectrum.