Radio Receiver Interference Measurement via Switched Load
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Solution Overview
Problem
Current wireless communication systems face challenges in accurately measuring radio frequency interference (RFI) in cellular networks, which affects sector load and overall throughput, as existing methods are not efficient in distinguishing between signal power and interference power.
Innovation Solution
A device and method that determine the rise-over-thermal value by measuring signal power when the receiver is coupled and de-coupled from the antenna, using a switch to couple a resistive load and maintaining constant gain, allowing for precise load determination and interference assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver continuously monitors signal power from the antenna, then the sector load can be monitored in real-time, but the measurement precision of interference power is degraded because the receiver cannot distinguish between signal power and interference power
Solution Approach 1:
The system performs preliminary action by having access terminals transmit pilot signals before normal data transmission. The radio node measures interference power from these pilot signals when the sector is lightly loaded, establishing a baseline interference level that can be used for subsequent load monitoring without requiring continuous interference-only measurements.
Solution Approach 2:
The system implements periodic action by having the receiver periodically switch between receiving mode (coupled to antenna) and measurement mode (de-coupled from antenna) at predetermined intervals. This periodic switching allows the system to alternate between monitoring signal power and measuring interference power, achieving both real-time load monitoring and precise interference measurement over time.
2Measurement precision
If the receiver is de-coupled from the antenna to measure interference power, then the measurement precision of interference power is improved, but the loss of time for data reception occurs
Solution Approach 1:
The system applies partial action by having access terminals transmit pilot signals for a fraction of the time (e.g., 10-20% of transmission time) rather than continuous transmission. This partial transmission approach provides sufficient data for interference measurement while minimizing the time loss for data reception. The pilot signals are transmitted periodically rather than continuously, achieving measurement precision without excessive time loss.
3Reliability
If the receiver gain is adjusted dynamically to maintain optimal signal levels, then the signal reception quality is improved, but the measurement precision of interference power is degraded due to gain variations
Solution Approach 1:
The system performs preliminary action by measuring and storing the receiver gain value before switching to interference measurement mode. This pre-measured gain value is then used to scale the interference power measurement taken when the receiver is de-coupled from the antenna, compensating for any gain variations and maintaining measurement precision while allowing dynamic gain adjustment during normal operation.
4Measurement precision
If multiple measurements are taken to improve interference measurement accuracy, then the measurement precision is improved, but the loss of time for measurements increases
Solution Approach 1:
The system implements periodic action by taking interference power measurements at regular predetermined intervals rather than continuously or ad-hoc. This periodic measurement approach ensures sufficient measurement accuracy over time while minimizing the total time spent on measurements. The system balances measurement frequency with operational efficiency by selecting optimal intervals based on the required measurement precision and system throughput requirements.
Data Source
AI summary
In a radio access network (e.g., a cellular network), a radio receiver is configured with a switch that alternatively couples an antenna and an impedance-matched load to the remainder of the receiver. Sector load, e.g., rise-over-thermal (ROT), is monitored by comparing a first measurement of signal power in a radio receiver (e.g., signal power output by the receiver) when the radio receiver is coupled to an antenna receiving the data traffic with a second measurement of signal power in the radio receiver when the radio receiver is de-coupled from the antenna.