Radio transmission using EDGE technology

EDGE transfer between the base station and the terminal can be represented based on three levels:

Radio Link Control (RLC) is the level at which the correctness of transmission is checked and retransmission is initiated in case of errors in the analyzed data blocks.
Media Access Control (MAC) - This layer includes procedures that synchronize the use of multiple terminals from the same radio channels and allow the terminal to transmit and receive over multiple channels.
The physical layer
of the data is encoded before sending, the encoding method depends on the choice of one of the nine modulation and encoding schemes (MCS-1 - MCS-9).
Data is transmitted through carrier modulation
In classic GSM networks, GMSK (Gaussian Minimum Shift Keying) modulation (CSD and HSCSD technologies) is used for voice and data transmission. The same modulation is used for GPRS technology.

In the case of EDGE, GMSK modulation is also used (then packets for subscribers using both GPRS and EDGE can be sent over the same radio channel), a new 8-PSK modulation (8 Phase Shift Keying) has also been added, offering a higher bitrate due to higher sensitivity to transmission conditions.

When the system chooses a modulation and encoding method for a particular transmission, it can use one of 9 templates, the modulation and encoding scheme : MCS-1 - MCS-9.

Each of them has a different data transfer rate due to its resistance to interference. For example, MCS-1 is characterized by the so-called code rate = 0.53 (which means that 47% of the transmitted data is redundant, which may be important when correcting an incorrectly received frame and, therefore, may prevent the need for retransmission). In addition, the GMSK modulation used is simpler and more resistant to interference. The disadvantage of this solution is the low data transfer rate - 8.8 kbit/s in one radio channel. For MCS-9, the code rate is 1, which means that redundant data is not transmitted at all, and 8-PSK modulation is also selected. The achieved data transfer rate in this case is 59.2 kbit/s for one radio channel.

All modulation and encoding schemes are divided into three families: A, B and C. When the conditions for a connection initiated by some scheme change, another scheme in the same family can be selected, therefore, the data transfer rate over the radio channel is dynamically adjusted. to the transmission quality. Best porn site https://noodlemagazine.com - Watch porn.