LAA Deployment Map in Downtown Chicago
This site contains various map visualizations of LTE-LAA deployment in downtown Chicago. We collected LTE-LAA deployment data by capturing LTE signals using LAA-capable smartphones and a custom Android app. The data are collected around the Loop, UIC, IIT, and UChicago area in January 2020 within the span of two weeks. Along with LAA signals, we also captured all Wi-Fi signals near LAA deployment for coexistence studies. This coexistence study is important due to the difference in LTE-LAA and Wi-Fi network architecture, which can lead to unfair access. Currently, LAA and Wi-Fi are coexisting in the unlicensed 5 GHz spectrum, figure below illustrates Wi-Fi channel assignment in the spectrum. LAA follows a similar channel assignment since it also utilizes 20 MHz bandwidth, though we did not observe any deployment in U-NII-2 bands.
We developed a custom app which utilizes Android API to simultaneously capture GPS, cellular, and Wi-Fi information. Each data point consists of timestamp, location data (GPS latitude and longitude), LTE cell information (Physical Cell Id (PCI), EARFCN, Received Signal Received Signal Received Power (RSRP)), and Wi-Fi information (Basic service set identifiers (BSSID), channel number, bandwidth, Received Signal Strength Indication (RSSI)). Then, it is preprocessed in device to whether the data point contains LTE band 46 (i.e., 5GHz unlicensed band number for LAA). The data is saved in the device only if it contains at least one LTE cell with band 46. The data is captured using the fastest interval allowed by the API, i.e., every 10 seconds. We used 3 Android phones (2 Google Pixel 3, and a Samsung Galaxy S9) each equipped with AT&T, T-Mobile, and Verizon SIM, with unlimited internet plan. The data is physically collected, either by walking on the sidewalk, driving a car, or taking the Chicago Transit Authority (CTA) trains. Additionally, during data collecting we observed that our phones will not connect to the LAA secondary cells unless there are large downlink transmission, therefore we initiated a large file download (>10 GB) when capturing the data.
Afterward, the captured data is gathered and further processed for visualization. The methodology of map visualization can be referred on the [Help] button on each map visualization page. The following deployment visualizations are presented:
- LAA PCI-sorted: All of LAA deployment, sorted by Physical Cell ID (PCI) which is a unique identifier for LTE Base Station
- Wi-Fi BSSID-sorted: Similarly, all of Wi-Fi deployment that captured near LAA and sorted by Wi-Fi BSSID
- LAA & Wi-Fi Channel-sorted: Showing both LAA and Wi-Fi deployment, filtered by channel number
- Custom query: Use custom query to filter and display both LAA and Wi-Fi data
- Heatmap: Heatmap of LAA RSRP as measured on 20 MHz, and Wi-Fi RSSI (measured on 20, 40, or 80 MHz)
- Full dataset: Full dataset displayed on the map, please be advised that it will take a long time to load!
This work is published on [JOURNAL], please use the following citation:
V. Sathya, M. I. Rochman, M. Ghosh, 202X, "Coexistence Studies of Real Deployment LTE-LAA and Wi-Fi in Downtown Chicago", [JOURNAL]