Tag Archives: radio

Different Categories of UE in LTE

Categories of UE in LTE is divided by its function which is as per below. Functionality: eNB obtains the UE radio capabilities via: • The S1AP initial setup request message • The X2AP in case of handover • The RRC…

Transmit Diversity & Receive Diversity

Transmit Diversity MISO = Multiple Input Single Output Principle More complex than SISO. 2 or more transmitters and one receiver. MISO is more commonly referred to as transmit diversity. The same data is sent on both transmitting antennas but coded…

How Adaptive Multi-Rate Codec (AMR) work in GSM ?

Adaptive Multi-Rate (AMR) codec consists of a family of codecs (source andchannel codecs with different trade-off bit-rates) operating in the GSM FRand HR channels modes The AMR system exploits the channel performance and robustness added bythe coding rates by adapting…

E-UTRAN (Evolved Universal Terrestrial Radio Access Network)

Role of Radio Access Network (RAN), namely NodeB and RNC is replaced with ENB, so as to reduce operational and maintenance cost of the device other than the simpler network architecture E-nodeB functions: all radio protocols, mobility management, header compression…

How Synchronization Channel Works in LTE?

After the power on, the UE knows:  the UE category and capability. the preferred PLMN. the carriers. The UE needs to know: The frame synchronization to be able to decode the DL radio frame. The cell parameters to be able…

Synchronization & BCH for TDD Frame in LTE

The Primary synchronization signal (PSS): is placed at the third symbol in subframes #1 and #6. The secondary synchronization signal (SSS): is placed at the last symbol in subframes #0 and #5. The S-RACH is transmitted on the UpPTS within…

Random Access Procedure in LTE

When the UE has obtained system information, it has to request an RRCconnection. Like it has no dedicated resources, the UE requests the connection using the Random Access Procedure using common uplink resources.  At the end of the procedure, the…

Step of RRC Connection Setup in LTE

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…

WCDMA Network Architecture

WCDMA including the RAN (Radio Access Network) and the CN (Core Network). The RAN is used to process all the radio-related functions, while the CN is used to process all voice calls and data connections within the UMTS system, and…

H-ARQ Mechanism in DL

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…

what is Radio Retransmission in LTE?

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…

WCDMA Interleaving

How WCDMA Interleaving ? Effect Interleaving is used to reduce the probability of consecutive bits error Longer interleaving periods have better data protection with more delay Channel coding works well against random errors, but it is quite vulnerable to bursts…