504 different physical-layer cell ids are composed of 168 different physical-layer cell id groups each of 3 physical layer ids within the group There are – primary synchronization signal – based on a frequency domain Zadoff-Chu sequence indicating the physical layer id, – secondary synchronization signal indicating the physical layer cell id group. The mapping … 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
Correlation Is a Measure of How Well a Given Signal Matches a Desired Code, The Desired Code is Compared to the Given Signal at Various Test times. Correlation is key enabling concept for direct sequence CDMA systems. Correlation is a measure of how well a given signal spread with a digital code matches a desired … Read more
The control plane includes the application protocol. It also includes the signaling bearers for transporting the application protocol messages. The application protocol is used for setting up bearers in the radio network layer. For example, radio access bearers or radio links. Figure shows “Control plane protocol stack” comprises Radio Resource Control (RRC), Packet Data Convergence … Read more
The scheduling is performed on cell basis. The two main functions are to decide which UE(s) shall be scheduled, the number of resources and the MCS to be applied. Furthermore the scheduler needs to be QoS aware. There is priority given to random access responses, control data, HARQ retransmissions. The channel quality may be taken … Read more
Hybrid ARQ (HARQ) leads to higher efficiency in transmission and error correction. There is one HARQ entity per UE with 8 stop-and-wait processes for each HARQ entity. Both incremental redundancy and chase combining are supported. The number of HARQ retransmissions targeted by the HARQ protocol depends on the network configuration. The BLER seen by RLC … Read more
Transport channels are used as the basic transmission service offered by layer 1 to MAC. MAC will use transport channels to multiplex and demultiplex logical channels onto and from them. In contrast to logical channel types, referring to the type of information transmitted, transport channel types are used to indicate the transport characteristics. This means … Read more
Here i write about Radio Link Control -RLC in LTE in a simple word. The RLC layer is located between the PDCP ( the “top” layer) layer and MAC layer (the “lower” layer). Communicates with the PDCP layer through a service access point ( SAP ) , and the MAC layer via logical channels. The … Read more
The figure below denotes the location of the X2 and S1 link with respect to the other network components within the LTE network. In general, the traffic on S1 interface is divided into two different plane, the control plane, which uses SCTP (Stream Control Transmission Protocol) developed by IETF for the purpose of transporting various … Read more