ratingla.blogg.se - Step enb boost

In CDMA, they call it 'Access Probe' as far as I know (but I don't have much knowledge on CDMA), in GSM they call it 'Channel Request', and in WCDMA / LTE they call it 'RACH'. Even though they use a little bit different name, in all cellular technology (CDMA, GSM, WCDMA, LTE) there is a specific signal that perform the same function. This is the first message from UE to eNB when you power it on. RACH stands for R andom A ccess Ch annel.

RRC Parameter to determine Preamble Type, Sequence Length, PRACH Transmission Time : prach-ConfigIndex.

Why are there different Preamble types ? The biggest reasons are to cover various range of distances between UE and Cell and to enhance reliable reception of the preamble with the optimal use of network resources.

What are main differences among the Preamble Formats ? : Length of Preamble.

Preamble format and Sequence Length : Format 0,1,2,3,4.

Possible Subcarrier Spacing of RACH Preamble : 1.25 Khz only.Two types of RACH Process : Contention based and Non Contention Based.What is it for ? It is for establishing Uplink Synchronization.