LTE RACH Preamble Generation - Nokia Parameters

LTE RF Optimization
LTE RACH Preamble Generation - Nokia Parameters
The preamble is a burst, which consists of a TCP (cyclic prefix), thus allowing for an efficient frequency-domain receiver at the eNodeB.
and a Sequence, the preamble length is shorter than the P RACH slot in order to provide room for a Guard Time to absorb the propagation delay.
The Guard time is required since the eNodeB does not know when the preambles will arrive.
an example with two UEs. The UE A is next to the eNodeB therefore there
is very little delay. In contrast UE “B” is some distance from the eNodeB, as such the initial access preamble is delayed, there is a round trip delay.
The eNodeB must allocate a large enough window such that the preambles from UE at the edge of the cell don’t arrive outside
of this window.
. In LTE there are four possible preamble format configurations possible.
The formats can have either short or long Cyclic Prefix (CP).
The long CP, used in formats 1, and 3 enable an increased tolerance for timing uncertainty.
By aggregating two preamble sequences, as done in formats 2 and 3, there can be better compensation for path loss, which also means that these two formats are better for cells of large radius.
Parameters:
- Root Sequence Index;
- High Speed Flag;
- Zero Correlation Zone Config.
#LTE #4G #rfengineering #5G #Nokia

[@abhinavpragya]

Very well explained about Ncs and cell radius..