Quick Answer
Slow data indoors can come from weak RSRP, low SINR, congestion, or a phone locked to a distant band. Record RSRP, SINR, band and the time of day before deciding whether a booster or capacity fix is needed.
Coverage or capacity?
If RSRP is weak, the phone is far from the serving cell or shielded by the building; improving the RF path helps. If RSRP is good but SINR or throughput is poor at busy times, the cell is congested; more booster gain will not add capacity.
| Symptom | Likely cause | First check |
|---|---|---|
| One bar, slow everywhere | Weak coverage | Outdoor RSRP and indoor RSRP |
| Full bars, slow at peak | Capacity / congestion | SINR, time of day, other users |
| Slow only in one room | Local shielding or shadow | Room-level RSRP/SINR |
What to record
- RSRP and SINR at the same spot, at peak and off-peak.
- The band and cell ID the phone is using.
- Whether the site has a dedicated internet backhaul or relies on mobile data.
- The number of concurrent users and devices in the area.
What to do next
For coverage-limited sites, design a passive DAS or a higher-gain donor path. For capacity-limited sites, discuss operator small cells, additional carriers or a private LTE/Wi-Fi offload plan. A booster is not a capacity solution.
Book a remote diagnosis
Share the site conditions and we will reply with a preliminary assessment and the measurements still needed.
Frequently Asked Questions
Will a booster make my data faster?
It can improve throughput when the limit is signal quality. If the cell is congested or the backhaul is saturated, a booster will not add capacity and may even amplify a poor signal.
Why is data fast outside but slow inside?
The building materials and the distance from the cell reduce RSRP and SINR indoors. Measure both levels at the same time; the difference is the building loss plus the indoor path loss.
Is 5G different?
5G coverage and band behavior differ by operator and market. Confirm the 5G bands in use before selecting a host; a 4G-only booster will not improve 5G data.