Here You Get how 3G work, Go inside WCDMA Technology and wcdma rf optimization.
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
Carrying information to acknowledge downlink transport blocks and feedback information to the system for scheduling and link adaptation of transport block CQI and ACK/NACK Physical Channel, Uplink, SF=256 A High-Speed Dedicated Physical Control Channel, or HS-DPCCH, is the third uplink channel for WCDMA. It makes it possible for changing power relations between to the dedicated … Read more
Carries physical layer signaling to a single UE, such as modulation scheme (1 bit), channelization code set (7 bit), transport block size (6bit), HARQ process number (3bit), redundancy version (3bit), new data indicator (1bit), UE identity (16bit) HS-SCCH is a fixed rate (60 kbps, SF=128) downlink physical channel used to carry downlink signaling related to … Read more
HS-PDSCH in WCDMA mainly for 2 works, Bearing service data and layer 2 overhead bits mapped from the transport channel SF=16, can be configured several channels to increase data service HS-PDSCH High-Speed Physical Downlink Shared Channel is a channel added to UMTS to increase downlink data rates. This is defined in Release 5 of the … Read more
The uplink DPDCH and DPCCH are I/Q code multiplexed. But the downlink DPDCH and DPCCH is time multiplexed. This is main difference. Basically, there are two types of downlink DPCH. They are distinguished by the use or non use of the TFCI field. TFCI bits are not used for fixed rate services or when the … Read more
There are two kinds of uplink dedicated physical channels, the Dedicated Physical Data Channel (DPDCH) and the Dedicated Physical Control Channel (DPCCH). The DPDCH is used to carry the DCH transport channel. The DPCCH is used to carry the physical sub-layer control bits. Each DPCCH time slot consists of Pilot, TFCI，FBI，TPC Pilot is used to … Read more
Here I write about what is main work of Acquisition Indicator Channel AICH in 3G There is 2 types main work of AICH Carrying the Acquisition Indicators (AI), SF = 256 There are 16 kinds of Signature to generate AI The Acquisition Indicator Channel (AICH) is a common downlink channel used to control the uplink … Read more
Here I write about PRACH Message Structure and PRACH Access Timeslot Structure for WCDMA 3G with its Flow in Image. The data and control bits of the message part are processed in parallel. The SF of the data part can be 32, 64, 128 or 256 while the SF of the control part is always … Read more
PRACH Physical Random Access Channel work in WCDMA Carrying uplink signaling and data, consist of two parts: One or several preambles: 16 kinds of available preambles 10 or 20ms message part The Physical Random Access Channel (PRACH) is used by the UE to access the network and to carry small data packets. It carries the … Read more