The technical details of the Radio Environment Map (REM).
- Definition and Purpose:
- A REM is a comprehensive wireless cognitive network map that represents the spatial distribution of various radio parameters within a given environment . These parameters include:
- Geographic information data.
- Radio device parameters.
- Radio propagation models.
- Spectrum data.
- A REM is a comprehensive wireless cognitive network map that represents the spatial distribution of various radio parameters within a given environment . These parameters include:
- Functionality and Applications:
- The REM serves several purposes in wireless communications:
- Spectrum Management: It provides reliable and adequate knowledge of crowd sensing devices, allowing efficient spectrum monitoring and management.
- Opportunistic Access: By understanding the radio environment, devices can opportunistically access available spectrum.
- Interference-Free Routing: The REM helps route signals through interference-free channels.
- Mobile Network Relaying: It aids in optimizing mobile network relaying.
- The REM serves several purposes in wireless communications:
- Challenges and Updates:
- As the wireless environment changes due to an increasing number of mobile devices, REM updates become crucial.
- Traditional update methods rely on data collection without considering whether the wireless environment has changed significantly.
- Frequent REM updates waste computational resources when the environment remains stable, while delayed updates reduce REM accuracy during significant changes.
- Proposed Update Mechanism:
- To address these challenges, a novel update mechanism combines the following techniques:
- Siamese Neural Network: Inspired by computer vision, this network compares newly collected crowdsourced data with the existing REM to measure similarity.
- Attention Mechanism: An attention mechanism further refines the update decision based on the amount of wireless environmental change.
- Controlled Update: By setting a similarity threshold, the algorithm achieves controlled REM updates with good controllability.
- To address these challenges, a novel update mechanism combines the following techniques:
- Simulation and Effectiveness:
- The proposed algorithm effectively detects changes in the wireless environment, as demonstrated through simulation data .