What is contention based Rach in LTE?
Machine-to-machine communication (M2M) is a technology to provide interaction among network devices without human intervention. Due to infrastructure characteristics, LTE networks are highly expected to become the deployment network of M2M devices.
What is LTE contention?
CONTENTION – FREE RANDOM ACCESS E.g. during handover a temporary valid preamble will be issued. It is dedicated to this UE. No contention resolution is needed as the preamble shall not be used by UEs which did not get assigned a dedicated preamble, i.e. randomly select one.
What is contention based random access?
Contention-based Random Access (CBRA): In contention based Random access, UE selects a Preamble randomly from a pool of preambles shared with other UE. This means that the UE has a potential risks of selecting the same preamble as another UE and subsequently may experience conflict or contention.
What is contention resolution timer in LTE?
This timer is to check if the eNB has sent the Contention Resolution Identity MAC CE in response to msg3 to complete the contention resolution procedure (for contention based mechanism). If no such message from eNB during this timer, then the new RACH procedure happened.
How contention resolution happens in LTE?
The Contention Resolution phase helps uniquely identify the UE that has been selected. In this scenario, contention resolution will resolve the random access procedure between UE-A and UE-B. UE-A does not have a permanent identity, so it picks a random number as the UE identity.
What is RRC connection request in LTE?
RRC CONNECTION REQUEST message is used to request the E-UTRAN for the establishment of an RRC connection. It is sent as part of the Random Access procedure. It is transferred using SRB0 on the Common Control Channel (CCCH) because neither SRB1 nor a Dedicated Control Channel (DCCH) has been setup at this point.
Why does LTE need Rach?
Another purpose of RACH process is to obtain the resource for Msg3 (Message 3). RRC Connection Request is one example of Msg3 and there are several different types of Msg3 depending on situation.
What are the different types of LTE handovers?
target cell/node. The parameters to measure and the thresholds for reporting are decided by the network. In LTE there are three types of handovers: • Intra-LTE: Handover happens within the current LTE nodes (intra-MME and Intra-SGW) • Inter-LTE: Handover happens toward the other LTE nodes (inter-MME and Inter-SGW)
How does L1 based contention resolution work in LTE?
L1 based Contention Resolution This procedure is always initiated from network in case of a handover. For this procedure, the eNB reserves a set of preamble sequence. When this type of scenario is encountered the eNB allocates the set from this reserved pool.This entire procedure is controlled by the eNB.
What does intra E UTRAN mean in LTE handover?
LTE Handovers – Intra E-UTRAN Handover. Posted on 10. Intra E-UTRAN Handover is used to hand over a UE from a source eNodeB to a target eNodeB using X2 when the MME is unchanged.
When to use non contention or Contention Access?
E.g. when UL synchronization status is “non-synchronized” or there are no PUCCH resources for SR available. • Non-contention based (applicable to only handover and DL data arrival). Normal DL/UL transmission can take place after the random access procedure. In total there are 64 preambles per cell.