Why uplink is greater than downlink

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Follow Why is uplink frequency higher than downlink frequency? GSM Physics. Upvote 0 Views Followers 3. In satellite communication, the uplink frequency is higher than the downlink frequency because the attenuation level increase with an increase in frequency. The power at the ground station Base Station is more than compared to the power available at the satellite.

More power is being required for high-frequency transmission. Satellites are constrained by their weight, being the cost around several thousands of euros per kilogram. For this reason, their equipment is also limited: they don't have big batteries and get their power essentially from solar panels.

Thus, they cannot use big power for transmission. As you very well stated, the attenuation is higher at higher frequencies. Since we have a power constrain, it seems logic to transmit in the lower frequency.

In the case of the UL, the so called "ground segment" consist essentially of several-dozen-meter-diameter antennas with whole buildings for the data processing and electrical supply, so the extra attenuation due to higher frequency is not as meaningful. In this case, the situation is just the opposite. The UL goes from the user phone to a fixed base station. You will check that the uplink frequencies are always smaller than downlinks'. In this case, it's the user's phone, which has a size constraint and relies on small batteries, while base stations usually have much better electric supplies with not such strigent requirements.

Thus, it makes sense that the Uplink in mobile communications employs the lower frequencies, while the base station employs higher ones. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. To participate you need to register. Registration is free. Click here to register now. Register Log in. JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding. You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser. Why uplink freq. Thread starter Bhanumurthy Start date Jun 19, Status Not open for further replies.

Bhanumurthy Full Member level 5. AdvaRes Advanced Member level 4. My question is abt the use of freq. This is only possible with the help of High power transmitter circuits Now the Satellite is a small piece of equipment and needs to be light weight However, i have few doubts.