Quickcomputerstips
- What is uplink transmission?
- Which technology does the uplink of an LTE system use?
- What are the key requirement in uplink power in LTE?
- Why uplink is higher than downlink?
- What is uplink and downlink in GSM?
- Why are two separate frequencies used for uplink and downlink transmission in case of satellite communication?
- What is uplinking and downlinking?
- What is downlink modulation?
- Which modulation technique is used in LTE for uplink transmission?
- Which is faster 4G or LTE?
- Why is OFDM not used in uplink?
- What is uplink power control in LTE?
- What is TPC command?
- What is closed loop control?
What is uplink transmission?
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.
Which technology does the uplink of an LTE system use?
While LTE's downlink uses OFDM, the uplink uses a different modulation scheme known as single-carrier frequency-division multiplexing (SC-FDMA). OFDM signals have a high peak to average power ratio (PAPR), requiring a linear power amplifier with overall low efficiency.
What are the key requirement in uplink power in LTE?
UE MAX POWER
It cannot transmit more than its maximum UE power which is commonly 23 dBm for most LTE UEs in the Uplink. The objective of the eNOdeB is that UE should transmit only enough power in the uplink in a range which is the minimum required amount. Neither more, nor less than that.
Why uplink is higher than downlink?
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 uplink and downlink 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.
Why are two separate frequencies used for uplink and downlink transmission in case of satellite communication?
It say basically the power at ground stations is more as compared to power available at satellites.So generally frequency for uplink is kept higher than the downlink. There is greater attenuation due to rain when the signal frequency is high.so downlink is also kept at lower frequency.
What is uplinking and downlinking?
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 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.
Which modulation technique is used in LTE for uplink transmission?
LTE devices use QPSK, 16QAM and 64QAM to modulate data and control information. The eNodeB supports all of these modulation techniques for the Down Link direction. However, 64QAM is optional in the Uplink direction.
Which is faster 4G or LTE?
In laymans terms, the difference between 4G and LTE is that 4G is faster than LTE. ... Older LTE mobile devices launched right prior to 4G deployment cannot provide 4G speeds because they aren't built to handle it. In 2020, all cellular carriers should now offer 4G service, if not offering 5G already.
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 uplink power control in LTE?
Uplink power control is a key radio resource management function. It is typically used to maximize the power of the desired received signals while limiting the generated interference. ... The LTE power control mechanism constitutes of a closed loop component operating around an open loop point of operation.
What is TPC command?
This kind of power control mechanism is often called "Closed Loop Power Control" and the special command being used for power control is called TPC (Transmit Power Control) command. In short, Transmit send something and the reciever send a feedback to the transmitter and the reciever retunes itself by the feedback.
What is closed loop control?
Closed Loop Power Control (CLPC) Measurement Description. Closed Loop Power Control (CLPC) measurement, as defined in TS 34.122 Section 5.4. 1.4, is used to test the ability of the UE transmitter to adjust its output power in accordance with one or more TPC commands received in the downlink.
