Beamforming In-Band Relay for Self-Interference and Coverage Control
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Solution Overview
Problem
Current wireless communication systems face challenges in increasing coverage area and reducing blind spots without increasing transmit power, which leads to interference and battery drainage issues in resource-limited devices.
Innovation Solution
An apparatus and method utilizing a noise-cancelling amplify and forward relay with beamforming techniques, including receive and transmit beamforming, and self-interference cancellation to amplify and forward signals at lower power levels, reducing signal leakage and improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If transmit power is increased to extend coverage area and remove blind spots, then coverage area is improved, but interference to nearby nodes increases and battery drainage worsens
Solution Approach 1:
An amplify-and-forward relay node is introduced as an intermediary between the central base station and distant clients. The relay receives signals from the base station, amplifies them, and retransmits them to extend coverage without requiring the base station to increase its transmit power, thereby avoiding increased interference to nearby nodes.
Solution Approach 2:
The communication system is segmented into multiple hops: base station to relay, and relay to client. This segmentation allows the relay to operate at lower power levels while still achieving extended coverage, reducing the harmful interference effect compared to a single high-power transmission from the base station.
2Area of stationary object
If transmit power is increased to extend coverage area, then coverage area is improved, but battery drainage of resource-limited clients worsens
Solution Approach 1:
The relay acts as an intermediary that performs signal amplification and forwarding, enabling distant clients to receive signals at lower power levels. This reduces the energy consumption and battery drainage for resource-limited mobile devices while still achieving extended coverage.
3Object-generated harmful factors
If transmit power is reduced to decrease interference, then interference is reduced, but coverage area deteriorates
Solution Approach 1:
By introducing a relay as an intermediary, the system can maintain low transmit power at both the base station and the relay, thereby keeping interference low while still achieving extended coverage through the multi-hop transmission path.
4Use of energy by moving object
If transmit power is reduced to decrease battery drainage, then battery drainage is reduced, but coverage area deteriorates
Solution Approach 1:
The relay serves as an energy-efficient intermediary that extends coverage without requiring clients to increase their transmit power, thereby reducing battery drainage while maintaining extended coverage area.
5Area of stationary object
If amplify-and-forward relay is used to extend coverage at lower power, then coverage area is improved and interference is reduced, but self-interference from transmit to receive front-end increases
Solution Approach 1:
The system applies preliminary anti-action by implementing self-interference cancellation techniques before the relayed signal is processed. This includes using receive beamforming to create nulls in the direction of the transmit antenna, thereby preemptively canceling the self-interference that would otherwise corrupt the received signal.
Solution Approach 2:
The patent applies local quality by using multiple receive antennas with different spatial characteristics. Each antenna experiences different levels of self-interference, and by combining their signals with appropriate weights, the system exploits these local differences to cancel self-interference while preserving the desired relayed signal.
6Reliability
If multiple receive antennas are used for receive beamforming to improve signal-to-noise ratio, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
Each receive antenna is equipped with a simple tunable filter that provides frequency-selective beamforming. This approach achieves signal-to-noise ratio improvement through spatial diversity while keeping the processing at each antenna relatively simple, balancing performance improvement with device complexity.
Data Source
AI summary
The methods and systems for amplify-and-forward (in-band) relaying relate to beamforming techniques including receive and transmit beamforming for reducing self-interference, and improving Signal-to-Noise Ratio (SNR), or Signal to Interference plus Noise Ratio (SINR), of an incoming signal (to be relayed). The incoming signal is amplified and retransmitted simultaneously with the incoming signal, and over the same frequency band as that of an incoming signal.