WDMA Air interface or Uu Interface contains 3 layers which describe as follow, The WCDMA layer 1 supports all functions required for the transmission of bit streams on the physical medium. It is also in charge of measurements function consisting in indicating to higher layers, for example, WCDMA Frame Error Rate (FER), WCDMA Signal to … Read more
The coding mode is called Regular Pulse Excited-Long Term Prediction (RPE-LTP). It works as follow: 8KHZ of sampling is performed first, then divided into frames with 20ms; every frame has 4 sub-frames; the duration of every sub-frame is 5ms; and the pure bit rate is 13kbit/s. The voice compression coding technique is widely used in … Read more
UTRAN (UMTS Terrestrial Radio Access network) structure The UTRAN consists of one or several Radio Network Subsystem ( RNS ), each containing one RNC and one or several NodeB. Interface Iu interface: the Iu interface connects the UTRAN to the CN and is split in two parts. The Iu-CS is the interface between the RNC … Read more
UMTS Closed Loop Mode Transmit Diversity Used in DPCH and HS-PDSCH. The closed-loop-mode transmit diversity can only be applied to the UMTS downlink channel if there is an associated UMTS uplink channel. Thus this mode can only be used with UMTS dedicated channels. The chief operating principle of the closed loop mode is that the … 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
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
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
Cell Search Procedure purpose is to give the UE the possibility of finding a wcdma cell and of determining the downlink scrambling code and frame synchronization of that wcdma cell. This is typically performed in 3 steps: PSCH (Slot synchronization): The UE uses the SCH’s primary synchronization code to acquire slot synchronization to a wcdma … Read more
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