Wireless Phone Isolation and Location Using TDD Uplink Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mobile communication terminal location tracking systems face challenges in accurately isolating and tracking devices on time-division duplexing frequency (TDD) networks due to interference between uplink and downlink signals, limiting precise geographical location estimation.
Innovation Solution
A system and method that reconfigures bandwidths by isolating the uplink bandwidth of a mobile communication terminal from the downlink bandwidth of an interrogation device, using a non-standard bandwidth at the end of the original bandwidth, and employs a power detection device (PDD) to measure RF signal power for precise location estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the original bandwidth is used for both uplink and downlink communication, then communication capacity is maintained, but signal interference occurs between uplink and downlink signals
Solution Approach 1:
The original bandwidth is divided into separate uplink and downlink frequency ranges. The downlink bandwidth is removed from the end of the original bandwidth, and a narrowed downlink bandwidth is created. The uplink bandwidth is calculated to be less than the removed downlink bandwidth, creating distinct non-overlapping frequency segments for uplink and downlink communication.
Solution Approach 2:
Different bandwidth configurations are applied to different directions of communication. The downlink uses a narrowed bandwidth (19 MHz from start of 20 MHz), while the uplink uses a specific allocated bandwidth (0.4 MHz at the end of 20 MHz). This local differentiation ensures no interference between uplink and downlink signals while maintaining communication functionality.
2Measurement precision
If bandwidth filtering is applied to measure only uplink signals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The power detection device is configured with a bandwidth filter that extracts only the uplink signal from the frequency spectrum. The filter is set to measure a bandwidth less than or equal to the calculated uplink bandwidth (0.2 MHz detection bandwidth), isolating the uplink signal from other frequencies. This extraction enables precise power measurement for location estimation without requiring complex signal processing.
Data Source
Figure 1
Figure 2
AI summary
A system for locating a mobile communication terminal, the system having an interrogation device, which is configured to solicit a mobile communication terminal of a wireless communication network to establish temporary communication with the interrogation device in an original bandwidth employed for communication between the interrogation device and the mobile communication terminal. Processors configured to isolate the uplink bandwidth of the mobile communication terminal by: configuring the interrogation device to remove a downlink bandwidth, to the wireless communication terminal, from an end of the original bandwidth to create a new downlink bandwidth; calculating an uplink bandwidth at the end of the original bandwidth to be less than the bandwidth removed from the downlink bandwidth; and reconfigure the mobile communication terminal to uplink to the interrogation device on the calculated uplink bandwidth at the end of the original bandwidth. The system further comprising a power detection device (PDD) configured to measure a power of a radio frequency (RF) signal emitted by the mobile communication terminal and having bandwidth filter configured to measure less than a calculated uplink bandwidth and locate the mobile communication terminal.