Solution to Challenges of In-band full-duplex communication by using electronics components

Three transmission modes are available for the communication systems, simplex, half-duplex and full-duplex. A simplex is considered least efficient, while a duplex is more efficient. Only one out of two devices can transmit in a simplex mode, and the transmission is in a single direction. For half-duplex transmission is bi-directional but not simultaneous. Full-duplex is considered to be more efficient to transmit in two directions simultaneously to increase the spectral efficiency and throughput of the channel. Spectral efficiency is the utilization of bandwidth for the users.  Due to higher efficiency, Full-duplex is has replaced half duplex in most communication systems. 

Every technology has its pros and cons. In the case of communication systems, the signal-to-noise ratio matters. In full-duplex systems, degraded ANR is observed to self-interference. The main challenge of full-duplex is to mitigate the self-interference that is caused due to internal components of the transmitter system. The receiver and transmitter antenna can cause self-interference due to antenna reflections in the propagation domain. In the analog domain, electronic components such as Low noise amplifiers, bandpass or bandstop filters, Power amplifiers, and mixers can cause self-interference due to their noise level and electromagnetic emissions. In the digital domain, bit propagation errors may cause self-interference. Domain-wise solutions can be implemented to cope with the challenges for better results.

To find the solution using the electronics component distributors, the best approach is to focus on the possible solution. In the propagation domain, antenna isolation can help achieve the best results. Best isolation leads to less self-interference. In the propagation domain, antenna separation beam phase control and different electronics components can help achieve the results. Electronics components, including the Hybrid coupler, rat-race coupler, etc., can provide isolation between the receiver and transmitter antenna. In addition to using a coupler, reflectors and absorbers can provide the isolation between the transmitter and receiver antenna. Phase controllers can also provide isolation by controlling the radiation phase and cancelation of the pattern at a specific phase. The best cancellation technique can be implemented in the analog domain, but the first requirement is known as noise floor. All the rated parameters of the components are already known. The fact above helps in understanding the residual Self-interference. The best approach is adaptive filters, tunable bandpass filters, and RF cancellers. In the Digital domain, the best algorithm is the only solution. Digital signal processors and Fpgas  can implement the algorithm and provide the best solution.  Digital filters (FIRs) and ADCs can implement digital cancellation.

In-band full-duplex, each element of the communication system, including antennas, low noise amplifier, ADC, etc., are the cause of significant self-interference that the implementation of a suitable technique can mitigate.