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
WCDMA Network Architecture The Wideband Code Division Multiple Access (WCDMA) network architecture: 1. User Equipment (UE): The UE, often a mobile phone or data card, is the device used by the end-user to access the WCDMA network. 2. UMTS Terrestrial Radio Access Network (UTRAN): UTRAN is the radio access network in WCDMA, consisting of NodeB … Read more
The state-of-the-art design of the LTE air interface is characterised by OFDMA (DL) and SC-FDMA (UL) together with MIMO. The downlink modulation is based on OFDMA (Orthogonal Frequency Division Multiple Access). OFDMA is a variant of OFDM which has the advantage that receiver complexity is at a reasonable level, it can handle scalable bandwidth requirements … Read more
Time switching transmit diversity TSTD in UMTS is used only on UMTS SCH channel Time-switched transmit diversity (TSTD) can be applied to the UMTS SCH. Just like Space time block coding based transmit antenna diversity STTD, the support of Time switching transmit diversity is optional in the UMTS UTRAN, but mandatory in the UE. The … 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