[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC):2025-08-18。"],[],[],null,["# CBRS spectrum availability\n\nYou can use the Google Maps interface in the Google Spectrum Access System (SAS)\nPortal to understand spectrum availability in the United States. This\nfunctionality includes [Dynamic Protection Area (DPA)](/spectrum-access-system/docs/key-terms#dpa)\nneighborhood borders and Citizens Broadband Radio Service (CBRS) spectrum availability\nheatmaps.\n\nDPA neighborhood borders\n------------------------\n\nDPA neighborhood borders show if your CBSD is in a DPA\nneighborhood. The CBSD in a DPA neighborhood might experience\nperiodic grant suspensions due to incumbent activity on one or several channels\nin the lower 100 MHz of CBRS.\n[Learn how to operate CBSDs near the coast](/spectrum-access-system/docs/cbsd/overview#cbsd-near-coast).\n\nTo check if a CBSD is inside a DPA neighborhood, follow these steps:\n\n1. Go to the [SAS Portal](https://wirelessconnectivity.google.com/sas/welcome).\n2. Select the deployment, and then click **Open**.\n3. Click *map* **Map view** , and then click *layers* **Overlays**.\n4. Select a **DPA Neighborhood** overlay to display the corresponding DPA neighborhood border on the map.\n5. On the map, check if your CBSD falls within the DPA neighborhood border.\n\nCBRS heatmaps\n-------------\n\nCBRS heatmaps help you to determine how many channels are\navailable in an area before you deploy a CBSD. Heatmaps assess\ngeneral spectrum availability before the deployment, while the spectrum inquiry\nresponse from SAS to a CBSD shows which channels\nare available for that CBSD based on its current registration\nparameters.\n\nCBRS heatmaps provide a granular and visual overview of spectrum\navailability from the 3550 MHz to 3700 MHz band in the United States.\n\nCBRS heatmaps account for all types of Tier 1 ([incumbent user](/spectrum-access-system/docs/key-terms#incubment))\nactivity, which includes the following:\n\n- Specialized sensors such as [Environmental Sensing Capability (ESC)](/spectrum-access-system/docs/key-terms#esc) devices\n- In-band DPAs with pending ESCs deployment\n- Out-of-band DPA protection\n- [GB-DPA](/spectrum-access-system/docs/key-terms#gbdpa) protection\n- Fixed satellite service (FSS)\n- US borders\n- Quiet zones, such as the [National Radio Quiet Zone (NRQZ)](/spectrum-access-system/docs/key-terms#nrqz) and the [Federal Communications Commission (FCC)](/spectrum-access-system/docs/key-terms#fcc)\n- Exclusion zones\n- Table mountain\n\nCBRS heatmaps *don't* account for the following activity:\n\n- Temporary channel suspensions due to incumbent activity within in-band DPAs that include [E-DPA](/spectrum-access-system/docs/key-terms#edpa).\n- Interference caused by existing CBSDs.\n\nCBRS heatmaps show the spectrum availability for a CBSD with the\nfollowing configuration:\n\n- Category A CBSD: uses a zero-gain omnidirectional antenna, which is mounted outdoors and five meters above ground.\n- Category B CBSD: has the same characteristics as a Category A\n CBSD but is mounted 25 meters above ground.\n\n | **Note:** In both the categories, the CBSD is supposed to be the first CBSD deployed in the area.\n- Heatmaps are intended as a guide to channel availability. The\n CBSDs that are deployed are not considered in this calculation.\n The spectrum availability might be lower in congested areas where\n SAS protects incumbents.\n\n- Heatmaps show how many full-power 10-MHz channels are available for the first\n CBSD in the area within 48 hours of deployment.\n\nTo find how many channels are available, follow these steps:\n\n1. Go to the [SAS Portal](https://wirelessconnectivity.google.com/sas/welcome).\n2. Select the deployment, and then click **Open**.\n3. Click *map* **Map view** , and then click *layers* **Overlays**.\n4. Select **Spectrum availability (Cat. A)** or **Spectrum availability (Cat. B)**.\n5. On the map, search for a location.\n6. In the **Spectrum availability** section, select the channels that are available within 48 hours.\n\nWhen you click anywhere on the map, it provides the location details such as\nelevation, clutter, height, and spectrum availability for Category A and\nCategory B CBSD.\n\nSpectrum availability information is also provided for every CBSD\nregistered with the SAS Portal. This information represents the\nresult of a real-time spectrum inquiry request for each CBSD. You\ncan view this information on the **Config** tab of the SAS\nPortal."]]