What is CQI in LTE?

What is CQI in LTE?

In the LTE system, the CQI is used by the mobile to indicate the channel quality to the eNB. The CQI reported value is between 0 and 15. This indicates the level of modulation and coding the UE could operate.

How is LTE speed calculated?

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 are subcarriers used for?

A subcarrier is a secondary modulated signal frequency modulated into the main frequency (the carrier) to provide an additional channel of transmission. It allows for a single transmission to carry more than one separate signal.

Why OFDM is used in LTE?

Orthogonal frequency-division multiplexing (OFDM), is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. OFDM meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates.

What is a subframe in LTE?

In LTE, DL and UL transmissions are organized into radio frames of 10 ms each. Each frame is divided into ten equally sized subframes. The duration of each subframe is 1 ms. Moreover, each subframe is further divided into two equally sized time slots, that is, each slot is 0.5 ms.

Will LTE work after 3G shutdown?

That all remains possible through 4G LTE, 5G, and Wi-Fi networks. With 3G turned off, the iPhone 3GS, for example, won't be able to make calls or text messages, but can still connect to Wi-Fi to access internet-based applications.

Is 4G going to be obsolete?

Many operators use 4G within their networks and worry that the arrival of the fifth generation means that their networks will soon become obsolete. Though this may be true one day, the shutdown of 4G is not likely to happen for at least another ten years.

Why is 5G so slow?

So, why are some 5G connections so slow? The first, and most impactful, reason is that the far-reaching 5G signals that have powered the vast majority of carrier rollouts in the US – especially from AT&T and, to a lesser extent, T-Mobile – have used low-band carrier frequencies.

Who has the fastest LTE?

SpeedSmart Speed IndexAT&T had the fastest 4G LTE network in the United States followed by T-Mobile. Both Verizon and T-Mobile showed impressive 5G network download speed for the country as a whole. Looking at individual cities below many locations show an average download speed of well over 100 Mbps on 5G.

Does LTE use GSM or CDMA?

GSM/UMTS, CDMA/CDMA200, and LTE are mobile standards that were developed to work with different networks. GSM and CDMA were used to move into the 2G network, while UMTS and CDMA2000 were used to transition into the 3G network. LTE, on the other hand, migrates CDMA/CDMA2000 and GSM/UMTS into the 4G network.