Wireless Base Station Sectorization for Satellite Interference
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Solution Overview
Problem
Inter-system interference occurs in satellite radioterminal communications systems due to terrestrial use and reuse of satellite frequencies, particularly when ancillary terrestrial networks operate in Time Division Duplex mode, affecting low elevation angle satellites.
Innovation Solution
Implementing sectorization methods for wireless base stations to transmit and receive satellite uplink frequencies in Time Division Duplex mode in one sector while refraining from doing so in another sector pointing to a low elevation angle satellite, and using different communication modes or air interfaces in various sectors to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If terrestrial networks reuse satellite frequencies in TDD mode, then system capacity and availability are improved, but interference with low elevation angle satellites occurs
Solution Approach 1:
The base station is divided into multiple sectors, each capable of independent operation. Sectors are segmented based on their satellite visibility characteristics, with some sectors operating in TDD mode and others in FDD mode or with reduced power, thereby localizing interference effects to specific geographic directions while maintaining overall system capacity
Solution Approach 2:
Different operational modes and power levels are applied to different sectors based on their local characteristics. Sectors with clear line-of-sight to low elevation satellites use FDD mode or reduced TDD power, while sectors blocked by terrain or structures can operate in full TDD mode, optimizing both capacity and interference reduction locally
2Device complexity
If a single antenna pattern covers the entire service region, then system simplicity is maintained, but frequency reuse and capacity are limited
Solution Approach 1:
The service region is divided into multiple sectors with distinct antenna patterns, each covering a specific geographic area. This segmentation enables frequency reuse across different sectors, as each sector can use the same frequencies without causing co-channel interference, thereby increasing overall system capacity while maintaining manageable complexity through standardized sector configurations
3Productivity
If TDD mode is used for terrestrial communications, then frequency efficiency is improved, but uplink frequencies interfere with satellite reception
Solution Approach 1:
TDD mode employs periodic time-division multiplexing where uplink and downlink transmissions occur in alternating time slots. By carefully coordinating the TDD frame structure and timing across sectors, uplink transmissions are concentrated in specific time windows, reducing continuous interference exposure for satellite receivers while maintaining high frequency efficiency during active transmission periods
Solution Approach 2:
The system dynamically adjusts TDD operational parameters such as uplink-downlink slot ratios, transmission power levels, and active sector configurations based on real-time satellite geometry and traffic conditions. This dynamic adaptation allows the system to optimize frequency efficiency when satellite interference is minimal while reducing TDD activity when low elevation satellites are visible
Data Source
AI summary
A wireless base station simultaneously transmits or receives wireless communications in different modes in different sectors of the wireless base station. The different modes may comprise a Time Division Duplex (TDD) mode and a non-TDD mode, and/or different air interfaces. Related methods and systems are described.