When the UE is powered up, it has to be RRC connected to be able to exchange data and signaling with the network. After the RRC connection, the Initial network attach allows to establish all the bearers to carry the data from the UE to the gateway. After the RRC connection, Signaling Radio Bearers (SRBs) … Read more
lets talk about LTE Architecture- SERVICE, EPC, E-UTRAN and User Equipment. In the LTE network is divided into 2 basic networks, namely: 1. EUTRAN (Evolved Universal Terrestrial Radio Access Network) 2. EPC (Evolved Packet Core) SERVICE IP Multimedia Subsystem (IMS) is a good example of cars that can be used in the service layer connectivity Services … Read more
MIMO-MU = Multi user It is used only in Uplink. MIMO-MU does not increase the individual user’s data rate but it does offer cell capacity gains that are similar to, or better than, those provided by MIMO-SU. The UE does not require the expense and power drain of two transmitters, yet the cell still benefits … Read more
MIMO = Multiple Input Multiple Output 2 or more transmitters and 2 or more receivers. MIMO transmits several streams whereas SIMO or MISO transmits only one stream. If there are N streams, there will be at least N antennas (here only 2). By spatially separating N streams across at least N antennas, N receiverswill be … Read more
1. The Transport block is transmitted to the UE on the PDSCH. 2. The UE receives it but it is erroneous. The TB is stored in a buffer. 3. The UE transmits directly a NACK concerning the erroneous block on the PUCCH. One HARQ entity in the UE and the e-UTRAN Made of 8 HARQ … Read more
The radio retransmission mechanism is called Hybrid Automatic Request (H-ARQ). H-ARQ allows to retransmit fastly erroneous blocks between the eNodeB and the UE. It avoids long retransmission between 2 TCP layers. The H-ARQ process runs in the eNodeB and in the UE. The H-ARQ is based on ACK/NACK messages carried by PUCCH or PUSCH. The … Read more
The QoS Class Identifier (QCI) is a scalar that is used as a reference to access node-specific parameters that control bearer level packet forwarding treatment (e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.). The Allocation and Retention Priority (ARP) primarily allows one to decide whether a bearer establishment request can … Read more
Transport channels are then mapped on the physical channels which are sent over the air interface A CRC is calculated and appended to each TB. It allows the receiver to detect errors. It is used by retransmission mechanisms like H-ARQ Depending on the Transport Format and the radio quality, the TB is coded and interleaved. … Read more
The MAC protocol provides the following services: Logical Channel to Transport channel mapping Scheduling: There is no dedicated channel allocated to a UE. Time and frequency resources are dynamically shared between the users in DL and UL. The scheduler is part of the MAC layer and controls the assignment of uplink and downlink resources. Multiplexing/Demultiplexing … Read more
The Radio Resource Connection (RRC) protocol is implemented in the eNodeB and the UE. In WCDMA, it is implemented in the RNC! RRC is the highest protocol in the control plane on the radio side. The RRC protocol allows: 2 instances (eNodeB and UE) to exchange signaling messages. to forward signaling messages coming from the … Read more