Here I Write about how the mapping can be done between logical, transport and physical channels. Not all physical channels are represented because not all physical channels correspond to a transport channel. The mapping between logical channels and transport channels is done by the MAC sub-layer. Different connections can be made between logical and transport … Read more
Random Access Procedure in UMTS In This article I write about step of Physical random access procedure in umts. As shown in below figure steps is as below. Derive the available uplink access slots, in the next full access slot set, for the set of available UMTS RACH sub-channels within the given ASC. Randomly select … Read more
In This article you found Application of Tx diversity modes on UMTS downlink physical channel or in other word transmit diversity mode in UMTS. Transmitter-antenna diversity can be used to generate multi-path diversity in places where it would not otherwise exist. Multi-path diversity is a useful phenomenon, especially if it can be controlled. It can … Read more
Effect Enhance the correlation among symbols so as to recover the signal when interference occurs Provides better error correction at receiver, but brings increment of the delay Channel Types No Coding Convolutional Coding (1/2, 1/3) Turbo Coding (1/3) UTRAN employs two FEC schemes: convolutional codes and turbo codes. The idea is to add redundancy … Read more
The TX diversity methods in the open-loop mode are as below Space time-block coding-based transmit-antenna diversity (STTD) Time-switched transmit diversity (TSTD). In UMTS STTD the data to be transmitted is divided between two UMTS transmission antennas at the base station site and transmitted simultaneously. The UMTS channel-coded data is processed in blocks of four bits. … Read more
Paging Indicator Channel PICH main work in 3G as below. Carrying Paging Indicators (PI) Fixed rate (30kbps), SF = 256 N paging indicators {PI0, …, PIN-1} in each PICH frame, N=18, 36, 72, or 144 The Page Indicator Channel (PICH) is a fixed rate (30kbps, SF=256) physical channel used by the NodeB to inform a … Read more