TDD Scheduler Gain Control for Distributed Antenna Interference
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Solution Overview
Problem
Distributed antenna systems face interference between downlink and uplink signals, which existing duplexers and filters fail to adequately address, limiting the use of frequency-agnostic radio frequency front-ends and increasing hardware complexity.
Innovation Solution
Implementing a time-division duplexing (TDD) mode scheduler and transmit/receive controller in distributed antenna systems to identify TDD transmission time-slots and adjust gain levels, increasing downlink power during TDD time-slots while reducing uplink power, thereby minimizing interference and reducing hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If duplexers or filters are used to protect received signals from interference, then signal isolation is improved, but device complexity and hardware requirements increase
Solution Approach 1:
The system dynamically changes the timing parameters of transmit and receive operations, switching between FDD and TDD modes based on traffic conditions. By adjusting the time-division duplexing slot allocations and using gain reduction during receive slots, the system achieves signal isolation without requiring complex hardware duplexers or filters
Solution Approach 2:
The system employs dynamic gain control that adjusts receiver gain based on whether the current time slot is configured for uplink or downlink transmission. This dynamic adaptation allows the same hardware to function in both FDD and TDD modes, eliminating the need for fixed-frequency duplexing hardware
2Object-affected harmful factors
If frequency-division duplexing with duplexers is implemented, then interference protection is improved, but adaptability to different frequency bands is reduced
Solution Approach 1:
The system designs the radio frequency front-end to be frequency-agnostic, capable of operating across multiple frequency bands without requiring hardware changes. The same universal hardware platform can be deployed for different frequency bands by simply reconfiguring the software-defined timing and gain parameters for TDD operation
Solution Approach 2:
The system changes operational parameters (timing slots, gain levels, frequency assignments) rather than physical hardware configuration when switching between frequency bands. This allows a single universal hardware design to adapt to different frequency bands while maintaining interference protection through software-controlled TDD mechanisms
3Area of stationary object
If downlink power is increased to improve coverage, then coverage area is improved, but uplink interference increases
Solution Approach 1:
The system uses periodic time-division slots where downlink transmission occurs in dedicated slots followed by uplink receive slots. During uplink receive slots, the system dynamically reduces receiver gain to attenuate strong downlink signals, allowing high downlink power to be used in coverage-enhancing slots without causing continuous interference to uplink reception
Solution Approach 2:
The system dynamically adjusts receiver gain based on the current time slot configuration. During slots designated for uplink reception, the gain is reduced to minimize the impact of strong downlink signals on the uplink path, while during downlink transmission slots, normal gain levels are restored to maintain coverage
Data Source
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AI summary
Certain features relate to operating a distributed antenna system or repeater system communicating frequency-division duplexing ("FDD") signals in a time-division duplexing ("TDD") mode. A TDD mode scheduler is configured for monitoring a downlink communications channel for the start of a downlink frame, sub-frame, or resource slot. Based on the start of a downlink frame, sub-frame, or resource slot, the TDD mode scheduler can identify a TDD transmission time-slot. The TDD mode scheduler can schedule high-powered downlink sub-frames during the TDD transmission time-slots where higher power output may be desirable. Based on the indication of the TDD transmission time-slot, a transmit/receive controller can increase the gain of the downlink communication and reduce the gain of the uplink communication.