What is the RSRP Transmit Power?
Let me explain this in a way that helps you clearly understand what’s happening when we talk about RSRP transmit power in LTE networks. You and I both know that signal strength is one of the most crucial elements when it comes to mobile network performance. So, let’s break it down together.
RSRP stands for Reference Signal Received Power. It’s the power level of the reference signals received by your device from a cell tower. These reference signals are sent out by the eNodeB (the LTE base station) to help your device measure signal quality and decide which cell to connect to or handover to. Now, you might be wondering — what is the “transmit power” behind these reference signals?
Here’s how you can think about it: the eNodeB transmits reference signals periodically over specific resource elements in the LTE downlink. These signals are transmitted at a certain power level, which is referred to as the RSRP transmit power. This power level contributes to how strong or weak the RSRP appears when it’s received by your device.
The RSRP transmit power depends on various factors, but generally:
- The total downlink transmit power of the eNodeB is divided among all the subcarriers and resource elements.
- The reference signals only occupy a small portion of the total bandwidth — specifically, they’re sent on specific subcarriers within each resource block.
- So, the power allocated to the reference signals is just a fraction of the total transmit power.
Let’s say the total downlink transmit power from the eNodeB is 46 dBm (which is common). The reference signals may get around 1/12th of that, because they are transmitted in 2 out of 12 subcarriers within each resource block in frequency. That means the RSRP transmit power per subcarrier could be around 30 to 36 dBm or even lower depending on configuration and scheduling.
But keep this in mind: the actual value received by your device is influenced by path loss, interference, and environmental conditions. So, even if the eNodeB transmits the reference signals at 33 dBm, your phone might receive it at -80 dBm, -100 dBm or even lower depending on your distance and surroundings.
To give you a more practical feel: if your RSRP value is around -90 dBm, you’re in a decent signal area. But if it goes to -110 dBm or worse, it means you’re in a low-signal zone and might start noticing slower speeds or dropped calls.
As we discussed in earlier articles about RSRP and SINR, the transmit power plays a key role in maintaining good signal coverage and quality. If you’re curious, we can also explore how this links with RSRQ (Reference Signal Received Quality) and how both of these impact your LTE experience.
So, in short, when we talk about RSRP transmit power, we’re referring to the power level used by the LTE base station to send out the reference signals, which your device then uses to assess the signal quality. Understanding this helps you better interpret signal readings and even troubleshoot connectivity issues when needed.