cyclic prefix in LTE
A cyclic prefix is a part of a symbol that is copied and added to the end of the symbol to prevent interference and improve synchronization.
A cyclic prefix is used in LTE because it is a technology that uses OFDM (Orthogonal Frequency Division Multiplexing) to transmit data over multiple subcarriers.
A cyclic prefix in LTE has two types: normal and extended. The normal cyclic prefix is shorter and more efficient, but the extended cyclic prefix is longer and more robust. The extended cyclic prefix is used in scenarios where there is high delay spread or high mobility, such as in rural areas or high-speed trains. The length of the cyclic prefix depends on the subcarrier spacing and the sampling frequency.
For example, if the subcarrier spacing is 15 kHz and the sampling frequency is 30.72 MHz, then the normal cyclic prefix is 4.7 microseconds and the extended cyclic prefix is 16.7 microseconds. The normal cyclic prefix has 7 symbols per slot and the extended cyclic prefix has 6 symbols per slot. A slot is the smallest unit of time in LTE, which is 0.5 milliseconds.
Comments
Post a Comment