Full Duplex Single Channel Communications Interference Suppression
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Solution Overview
Problem
Conventional two-way communication systems face challenges in achieving full duplex operation due to insufficient isolation between transmit (Tx) and receive (Rx) signals, especially in scenarios where precise frequency separation is not feasible, such as in mobile or portable devices with large wavelength dimensions.
Innovation Solution
The implementation of full duplex single channel (FDSC) systems, which enable simultaneous Tx and Rx operations on the same frequency by using techniques like time division duplexing (TDD) and interference suppression methods, such as antenna cancellation and digital interference cancellation, to minimize Tx-to-Rx interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency division duplexing (FDD) is used to separate Tx and Rx bands, then Tx-to-Rx interference is reduced, but bandwidth efficiency decreases and frequency separation becomes impractical for portable devices
Solution Approach 1:
The patent changes the frequency parameter by operating Tx and Rx on the same frequency instead of separated frequencies, enabling full duplex single channel operation that doubles bandwidth efficiency while managing interference through other means
Solution Approach 2:
The patent introduces an intermediary cancellation signal that mimics the self-interference characteristics and subtracts it from the received signal, effectively removing the harmful Tx-to-Rx interference component
2Reliability
If frequency separation is used to prevent Tx signal leakage into Rx path, then communication reliability is maintained, but device complexity increases and antenna mounting area requirements increase
Solution Approach 1:
The system uses digital signal processing as an intermediary to cancel interference, replacing complex analog filtering and physical separation requirements with computational methods that reduce hardware complexity
Solution Approach 2:
The patent replaces mechanical/physical separation methods (frequency separation, spatial isolation) with digital signal processing techniques, substituting physical system complexity with computational solutions
3Productivity
If simultaneous Tx and Rx operations on the same frequency are implemented, then bandwidth efficiency doubles, but Tx signal interference into Rx path becomes severe
Solution Approach 1:
The patent uses digital interference cancellation as an intermediary process that estimates and subtracts the self-interference component from the received signal, enabling simultaneous Tx and Rx operations on the same frequency
Solution Approach 2:
The system employs feedback mechanisms where the transmitted signal is used to estimate the self-interference component, which is then subtracted from the received signal in a closed-loop cancellation process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
FDSC systems effectively double bandwidth efficiency and maintain reliable communication in both directions, even in scenarios where conventional frequency separation is impractical, by achieving significant suppression of Tx signal interference into the Rx path.
Implementation Method 1
antenna cancellation and digital interference cancellation, to minimize Tx-to-Rx interference
Implementation Method 2
antenna cancellation and digital interference cancellation, to minimize Tx-to-Rx interference
Data Source
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Figure 1B
Figure 1C
AI summary
Embodiments contemplate TDD systems and techniques where timeslots may be allocated as DL, UL, or FDSC; the base station (BS) may be full duplex singled channel (FDSC) capable; and some, all, or none of the UEs (or WTRUs) may be FDSC capable. In one or more embodiments, FDSC1 timeslots may be contemplated that may be used (in some embodiments perhaps exclusively used) by a pair of radios, for example one BS and one UE, both having FD capability. In one or more embodiments, FDSC timeslots may be shared among a BS with FDSC capability and two or more UEs, that may be half duplex (HD). Embodiments also contemplate various FDD systems and techniques, including full duplex FDD systems and techniques.