Spectrum Access System Optimizing TDD Synchronization in SON
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Solution Overview
Problem
Current wireless network systems face challenges in efficiently managing and optimizing shared spectrum access, particularly in multi-operator and multi-technology environments, leading to signal interference issues due to unsynchronized base-station transmissions and lack of accurate timing capabilities.
Innovation Solution
A Spectrum Access System (SAS) collects network information from various sources to optimize Time Division Duplex (TDD) synchronization and resource allocation across different networks, operators, and technologies, using a global Neighbor Relation Table and Radio Environment Map to minimize interference and improve network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic spectrum access systems are used to share spectrum among multiple users, then spectrum utilization efficiency is improved, but coordinating and managing multi-user access becomes more complex
Solution Approach 1:
The system segments the spectrum access management function by introducing a centralized Spectrum Access System (SAS) that operates independently from individual base stations. The SAS receives measurements from multiple base stations, performs centralized optimization calculations, and returns coordinated channel assignments and power levels. This segmentation separates the complex coordination logic from the distributed base stations, enabling efficient multi-user spectrum sharing while managing complexity through centralized processing.
2Adaptability or versatility
If base stations transmit without synchronized timing, then network deployment flexibility is improved, but signal interference between base stations increases
Solution Approach 1:
The system performs preliminary timing synchronization by having base stations transmit synchronization signals at predetermined times before actual data transmission begins. The SAS uses these preliminary synchronization signals to establish a coordinated timing framework across multiple base stations. This preliminary action enables the system to maintain network deployment flexibility while preventing signal interference through advance timing coordination.
Solution Approach 2:
The system implements feedback mechanisms where base stations transmit measurements of their local timing and signal conditions to the SAS. The SAS uses this feedback information to calculate optimal transmission times and power levels for each base station. This feedback loop enables the system to adapt to varying network conditions while maintaining synchronization and minimizing interference across the distributed network.
3Productivity
If secondary users dominate spectrum usage in shared bands, then overall resource usage is improved, but interference with primary users increases
Solution Approach 1:
The system applies preliminary anti-action by having the SAS calculate and enforce maximum power levels for secondary users before they transmit. The SAS receives measurements from both primary and secondary users, performs interference calculations, and returns optimized power levels that prevent secondary users from causing unacceptable interference to primary users. This preliminary anti-action allows secondary users to dominate resource usage while containing interference through pre-calculated power limits.
Data Source
AI summary
Improved techniques are provided for managing and optimizing network resources and spectrum access in a Self-Organizing Network (SON). A Spectrum Access System (SAS) collects network-related information from a plurality of network sources, such as base stations and user equipments (UEs), to perform optimization and organization across different networks, network operators, and network technologies. In some embodiments, the SAS may use the network information and a Radio Environment Map to optimize TDD synchronization in the SON. In other embodiments, the SAS may use the network information to populate a global Neighbor Relation Table. The SAS also may use the network information to optimize one or more network parameters, such as Physical Cell Identities or Root Sequence Indexes, antenna parameters, transmit power levels, handover thresholds, channel assignments, and so on, for use in the SON. Advantageously, the SAS's optimized network parameters may be used to improve network performance, reduce signal interference, and adjust to network failures in the SON.