| LTE (Long Term Evolution) is a technology of | | | | important element of LTE is a new network |
| mobile networks in which the download speed will | | | | structure, called System Architecture Evolution |
| reach up to 326 Mb/s and upload speed up to 86 | | | | (SAE). It is based entirely on IP protocol. The |
| Mb/s (20 MHz channel, 64QAM modulation, 4x4 | | | | technology is evolving in two directions: FD-LTE |
| MIMO). The technology is seen as the next stage | | | | and TD-LTE. They differ in the utilization of the |
| in the development of mobile networks, allowing | | | | channel. In the case of FD-LTE, the transmission |
| them to achieve the possibility of efficient | | | | channel is divided into two frequency bands - one |
| multimedia transmission. The popularity of | | | | of them is used for transmission towards the |
| smartphones (like iPhone) means the growing | | | | base station and the second from the base |
| demand for mobile broadband networks. LTE | | | | station to the terminal. |
| technology is flexible, both in terms of frequency | | | | The TD-LTE uplink and downlink transmissions are |
| band and width of the transmission channel. | | | | spread over the whole channel. The time at which |
| Depending on the needs, LTE networks can | | | | transmission is carried out is divided into time |
| operate at frequencies from 700 MHz (rural areas | | | | slots, separated by guard time. In each time slot |
| - higher ranges) to 2.6 GHz (metropolitan areas). | | | | the transmission goes only one way. This allows |
| It is possible to use transmission channels with the | | | | for flexible use of the capacity of the |
| following bandwidths: 1.4 MHz, 3 MHz, 5 MHz, 10 | | | | transmission channel. |
| MHz, 15 MHz, and 20 MHz. With the increase in | | | | Currently, TD-LTE is gaining more and more |
| channel width, the link speed rises as well. | | | | supporters; not without significance is the fact |
| The "downlinks" use OFDM spread spectrum | | | | that it is chosen as the primary technology for |
| technique with multiple subcarriers, whereas the | | | | building commercial LTE networks in China. |
| "uplinks" are based on SC-FDMA (Single Carrier | | | | The first commercial LTE networks will be |
| Frequency-Division Multiple Access) that uses a | | | | launched in 2010 (China, USA, Scandinavia, Japan), |
| single carrier (to save the battery life of the client | | | | however, works are already carried out to |
| device) . Additionally, LTE uses Multiple Input | | | | develop a more advanced version of this |
| Multiple Output (MIMO) technology which utilizes | | | | technology, namely LTE-A (Advanced), with |
| many antennas. So far, client terminals are usually | | | | estimated throughput of 1 Gb/s (downlink) and |
| equipped with two antennas (MIMO 2x2), due to | | | | 500 Mb/s (uplink) within a 100 MHz band. |
| implementation problems in such small devices. An | | | | |