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.

What is the difference between uplink and downlink?

In satellite telecommunication, a downlink is the link from a satellite down to one or more ground stations or receivers, and an uplink is the link from a ground station up to a satellite. Some companies sell uplink and downlink services to television stations, corporations, and to other telecommunication carriers.

What is the relation between uplink and downlink frequency?

The uplink frequency is the frequency which is used for transmission of signals from earth station transmitter to the satellite. The downlink frequency is the frequency which is used for transmission of signals from the satellite to the earth station receiver.

Why are uplink and downlink frequencies not the same in satellite Mcq?

Explanation: The transmitter-receiver combination in the satellite is known as a transponder. ... The reason for frequency translation is that the transponder cannot transmit and receive on the same frequency. 3. The downlink frequency is lower than the uplink frequency.

Can the same frequency be used for uplink and downlink communication?

The uplink and downlink transmitters use separate frequency bands for transmissions; therefore, both downlink and uplink transmitters can transmit at all times and at the same time [3].

Communication Systems - Uplink and downlink frequency¦¦why uplink is greater than to downlink

Why the uplink frequency is always greater than the downlink frequency in satellite communication?

The uplink frequency is higher than that of the down because the transmit amplifier in the down link has a limited power supply power budget as it is on board of the satellite where the satellite is powered by photovoltaic generators.

What is uplink and downlink in LTE?

The actual implementation of the technology will be different between the downlink (i.e. from base station to mobile) and the uplink (i.e. mobile to the base station) as a result of the different requirements between the two directions and the equipment at either end.

Why FM is used in satellite communication?

In the case of FM, Bandwith is large and noise immunity is high that's why it is used in satellite communication. whereas in AM B.W is 2 f_m, in DSB-SC BW is 2 f_m, SSB-SC BW is f_m. So we can see the B.W of FM is large, as compared to other schemes.

What is uplink and downlink frequency in GSM?

GSM-900 uses 890 - 915 MHz to send information from the Mobile Station to the Base Transceiver Station (BTS) (This is the “uplink”) and 935 - 960 MHz for the other direction (downlink), providing 124 RF channels spaced at 200 kHz. ... Duplex spacing is 95 MHz.

What is the maximum distance covered by satellite communication?

MEO satellites operate from 10,000 to 20,000 km (6,300 to 12,500 miles) from Earth. (Satellites do not operate between LEO and MEO because of the inhospitable environment for electronic components in that area, which is caused by the Van Allen radiation belt.)

What is the function of the uplink?

Pertaining to radiocommunication service, an uplink (UL or U/L) is the portion of a feeder link used for the transmission of signals from an earth station to a space radio station, space radio system or high altitude platform station.

What downlink means?

: to transmit (data) from a spacecraft or satellite to a receiver on earth.

What is downlink modulation?

The downlink data modulation transforms the block of scrambled bits to a corresponding block of complex modulation symbols. The set of modulation schemes supported for the LTE downlink includes QPSK, 16QAM, and 64QAM, corresponding to two, four, and six bits per modulation symbol respectively.

What is uplink and downlink in mobile communication?

Uplink and downlink, also called upload and download, refers to the two-way communication between a cell tower and your phone. Downlink definition – signal coming from a cell tower to your cellular device. Uplink definition – signal leaving your cellular device and going back to a cell tower.

What frequency is 5G?

5G Ultra Wideband, Verizon's millimeter wavelength (mmWave)-based 5G, operates at frequencies of about 28 GHz and 39GHz. This is considerably higher than 4G networks, which use about 700 MHz-2500 MHz frequency to transfer information.

What band is 850 MHz?

Band 5 (850 MHz) Band 4 (1700/2100 MHz) Band 66 (Extension of band 4 on 1700/2100 MHz).

What is difference between AM and FM?

The difference is in how the carrier wave is modulated, or altered. With AM radio, the amplitude, or overall strength, of the signal is varied to incorporate the sound information. With FM, the frequency (the number of times each second that the current changes direction) of the carrier signal is varied.

Why FM is called nonlinear modulation?

Non linear modulation act as nonlinear system: the bandwidth of the modulated signal is wider and can be alterated in terms of ratio between two spectral components with respect to the modulating signal.

What is the difference between FSK and FM?

Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. ... FSK is widely used in computer modems, such as fax modems, telephone caller ID systems, garage door openers, and other low-frequency transmissions. Radioteletype also uses FSK.

Why SC FDMA is used in uplink?

SC-FDMA is a modulation scheme used by LTE-LAA uplink as it provides significantly lower Peak to Average Power Ratio (PAPR) compared to OFDM [72] . Likewise OFDM, SC-FDMA also produces orthogonal subcarriers. ...

Why is OFDM not used in uplink?

OFDMA is used on the downling, but since it presents a high Peak-to-average Power Ratio it is not possible to use it on the uplink.

What is the maximum downlink data rate of LTE network?

So the total bits carried by 300 subcarriers for the duration of a symbol is 300 X 6 = 1800 bits. Again 1 symbol is of 71.4 microseconds for LTE. So the data rate is 1800 / 71.4 = 25.2 Mbps. For 10 MHz using the same formula the maximum data rate in downlink is 50.4 Mbps and for 20 MHz it is 100.8 Mbps.

What is difference between active and passive satellite?

In addition to amplification, it performs frequency translation of the received signal before retransmission. Active satellite can generate power for its own operation. ... The passive satellite is a reflector which receives the signal from the transmitting earth station and scatters the signal in all the directions.