--- title: "Satellite direct to device in a mountain | Nexus Observatory" description: "Where the valley cell cannot reach, phones on the pass road connect straight to a low-orbit satellite, which relays through its feeder link to a gateway." url: https://observatory.global/environments/networks/ntn-d2d/ publisher: Nexus Observatory Inc. updated: 2026-10-29 --- Satellite direct to device in a mountain valley. A mountain valley: the village is covered by a cell on the spur; the road to the pass is not. Layers Scenario A mountain valley: the village is covered by a cell on the spur; the road to the pass is not. 01/05 500 MHz 1 GHz 2 GHz 5 GHz 10 GHz 20 GHz 40 GHz n28 700 MHz: 703–803 MHz · λ 40 cm · Coverage layer, NB-IoT and LTE-M anchor · 3GPP TS 38.101-1 Network scenes # Satellite direct to device in a mountain valley Where the valley cell cannot reach, phones on the pass road connect straight to a low-orbit satellite, which relays through its feeder link to a gateway. Slant range, delay, Doppler and SNR are computed for the pass geometry. [Radio access in a city centre](https://observatory.global/environments/networks/ran-city/) [Open RAN in a suburb](https://observatory.global/environments/networks/oran-suburb/) [AI-RAN at a stadium](https://observatory.global/environments/networks/ai-ran-stadium/) [Private 5G in an open-pit mine](https://observatory.global/environments/networks/private5g-mine/) [Private 5G at a container port](https://observatory.global/environments/networks/private5g-port/) [LoRaWAN across a farm and village](https://observatory.global/environments/networks/iot-farm/) [IoT in the city: a street-light mesh and LoRaWAN](https://observatory.global/environments/networks/iot-city/) [Industrial IoT in a process plant](https://observatory.global/environments/networks/iot-plant/) [Satellite direct to device in a mountain valley](https://observatory.global/environments/networks/ntn-d2d/) [Microwave backhaul across a river valley](https://observatory.global/environments/networks/backhaul-fresnel/) The place: [Alpine valley](https://observatory.global/environments/alpine-valley/) ## In this scene **LEO satellite with a regenerative payload**: A low-orbit satellite whose spot beam (about 50 km across at 600 km) serves standard phones in the S band; drawn far lower than its true height. (3GPP TS 38.300 §16.14 (NR NTN), 3GPP TR 38.821, 3GPP TS 38.101-5) Scene input: TR 38.821 set 1, LEO-600 S-band: 34 dBW/MHz EIRP density **Satellite gateway (feeder link)**: The ground station that links the satellite to the core network over a Ka-band feeder link; it may be hundreds of kilometres away. (3GPP TR 38.821, ITU RR Art. 5) **Valley cell site**: A 700 MHz sector on the spur above the village: it covers the valley floor; the ridges shadow the pass road. (3GPP TS 38.104, 3GPP TR 38.901 UMa) ## Computed for this scenario **Outdoor area at SINR ≥ 10 dB**: 55 % **Median SINR**: 13.1 dB **Shannon bound at median, 20 MHz**: 88 Mbit/s **Cell edge (5th percentile)**: -8.9 dB · 3 Mbit/s **Slant range**: 718 km at 55° elevation **Free-space loss (P.525)**: 155.6 dB at 2.00 GHz **One-way delay**: 2.39 ms **Doppler, worst case at this elevation**: ±13.2 ppm · 26 kHz **Downlink SNR, handheld, 5 MHz**: 15.4 dB ## Scenarios **Pass at 55°**: The satellite is 55° above the horizon: about 720 km of slant range. **Low pass at 25°**: Low on the horizon the slant range doubles, the loss grows by about 5 dB and the Doppler rises. **Overhead**: Directly overhead the path is shortest and the Doppler goes to zero. ## Tour transcript 1. A mountain valley: the village is covered by a cell on the spur; the road to the pass is not. 2. The valley cell at 700 MHz: the ridges cast its shadow over the switchbacks. 3. A low-orbit satellite serves phones on the pass directly and relays through its Ka-band feeder link to a gateway. 4. Low on the horizon the slant range doubles and the Doppler rises: the readouts are recomputed. 5. Overhead, the shortest path and no Doppler. ## How the numbers are computed Slant range on a spherical Earth for the elevation angle, free-space loss (ITU-R P.525) at 2 GHz, one-way delay as range over c, and the worst-case Doppler v cos ε · Re/(Re + h) / c at that elevation (3GPP TR 38.821 geometry). Downlink SNR uses the TR 38.821 set-1 LEO-600 S-band EIRP density over 5 MHz to a 0 dBi handheld with a 7 dB noise figure. The valley cell uses TR 38.901 UMa with line of sight tested against the terrain. © 2026 Nexus Observatory Inc. **Legal** [Privacy notice](https://observatory.global/legal/privacy/) · [Terms of use](https://observatory.global/legal/terms/) · [Cookie policy](https://observatory.global/legal/cookies/) · [Accessibility](https://observatory.global/legal/accessibility/) · [Official languages](https://observatory.global/official-languages/) · [Trademarks](https://observatory.global/trademarks/) · [Notices](https://observatory.global/notices/) **Company** [About](https://observatory.global/about/) · [Stewardship](https://observatory.global/consortium/) · [Contact](https://observatory.global/contact/)