# How does higher received signal power enable higher data rates?

On page 30, of the book Fundamentals of LTE by Arunabha Ghosh et al. it is written:

This allows broadcast signals from different cells to combine over the air to significantly enhance the received signal power, thereby enabling higher data rate broadcast transmissions for a given transmit power.

How does higher received signal power enable higher data rates?

• Does this answer your question? Calculating Data Rate using Bandwidth, Transmission Power, Noise Power Spectrum Density and Channel Gain Jul 22 at 10:00
• well, does it answer your question? Jul 22 at 10:17
• @MarcusMüller No I think it doesn't. The other question is a numerical problem, while this one is a conceptual one. Jul 22 at 10:19
• Don't take this the wrong way, but if that sentence causes you trouble, you shouldn't be reading Ghosh. Start with (for example) any of the communications books by Haykin, and take it from there.
– MBaz
Jul 22 at 12:04
• I didn't see it :) Good for you. I suggest listening to Marcus, too!
– MBaz
Jul 22 at 14:06

The answer is Shannon's limit, which is given by:.

$$C = B log_2 (1 + γ)$$

where $$C$$ is the “capacity,” or maximum error-free data rate, $$B$$ is the bandwidth of the channel, and $$γ$$ is the SNR (or SINR).

As received signal power increases, the Signal to Noise Ratio (SNR), $$\gamma$$, increases, since SNR is the ratio of signal power to the noise power. If $$\gamma$$ increases, the maximum possible data rate, $$C$$, increases.

• This answer goes a bit short - received power in itself does not increase your rate; it needs to be "useful"; and in that sense, you'd need to see the statement of the book in more context: Probably, before it says ".. a combiner in the receiver phase-accurately adds up the signal"; even without the phase correction, power might increase – but not the information rate. You hide that in the $\gamma$, which is fine, but really, you need to also look closely how you come from received power to SINR, because received power is S+I! Jul 22 at 10:22
• You're not in the SNR-limited case here, but in the SINR-limited case, if we're talking about signals from mutliple cells. Jul 22 at 10:24
• @MarcusMüller thanks for the clarification, I've edited my answer. The book does not say the data rate increases, rather it enables high data rate communication Jul 22 at 10:24
• hmmmm OK, well, but then me welding next to your phone would also enable high data rate communications? Jul 22 at 10:25
• @MarcusMüller I'm still studying it. I'll definitely add it to my answer once I get it. Thanks for the pointer! Jul 22 at 13:12