Residual self-interference cancellation in NOMA-OFDM full duplex massive MIMO

2017 ◽  
Author(s):  
Nessrine Smaili ◽  
Mustapha Djeddou ◽  
Arab Azrar
Keyword(s):  
Interference Cancellation ◽  
Massive Mimo ◽  
Full Duplex

A tuneable rat-race coupler for full duplex communications

2021 ◽  
pp. 1-7
Author(s):  
G. T. Watkins
Keyword(s):  
Interference Cancellation ◽  
Phase Shifter ◽  
Dipole Antenna ◽  
Full Duplex ◽  
Frequency Channel ◽  
Ism Band ◽  
Single Antenna ◽  
Variable Attenuator ◽  
Degree Of Isolation ◽  
Better Than

Abstract Full duplex (FD) could potentially double wireless communications capacity by allowing simultaneous transmission and reception on the same frequency channel. A single antenna architecture is proposed here based on a modified rat-race coupler to couple the transmit and receive paths to the antenna while providing a degree of isolation. To allow the self-interference cancellation (SiC) to be maximized, the rat-race coupler was made tuneable. This compensated for both the limited isolation of the rat race and self-interference caused by antenna mismatch. Tuneable operation was achieved by removing the fourth port of the rat race and inserting a variable attenuator and variable phase shifter into the loop. In simulation with a 50 Ω load on the antenna port, better than −65 dB narrowband SiC was achieved over the whole 2.45 GHz industrial, scientific and medical (ISM) band. Inserting the S-parameters of a commercially available sleeve dipole antenna into the simulation, better than −57 dB narrowband SiC could be tuned over the whole band. Practically, better than −58 dB narrowband tuneable SiC was achieved with a practical antenna. When excited with a 20 MHz Wi-Fi signal, −42 dB average SiC could be achieved with the antenna.

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