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WCDMA
Orthogonal Code Usage – Coding & Decoding in WCDMA
How Orthogonal Code works in WCDMA? 1.Coding By spreading, each symbol is multiplied with all the chips in the orthogonal sequence assigned to the user. The resulting sequence is processed and is then transmitted over the physical channel along with…
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…
Signal Fading
Slow fading: In case shadow effect is caused by obstacles, and the receiving signal strength decreases but the field strength mid-value changes slowly with the change of the topography, the strength decrease is called “slow fading” or “shadow fading”. The…
What is HS-DPCCH and High-Speed Dedicated Physical Control Channel work in WCDMA
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…
Processing Procedure of WCDMA System
Source coding can increase the transmitting efficiency. Channel coding can make the transmission more reliable. Spreading can increase the capability of overcoming interference. Through the modulation, the signals will transfer to radio signals from digital signals. Bit, Symbol, Chip Bit…
WCDMA Source Coding
AMR (Adaptive Multi-Rate) Speech A integrated speech codec with 8 source rates The AMR bit rates can be controlled by the RAN depending on the system load and quality of the speech connections Video Phone Service H.324 is used for…
WCDMA Block Coding – CRC
Block coding is used to detect if there are any uncorrected errors left after error correction. The cyclic redundancy check (CRC) is a common method of block coding. Adding the CRC bits is done before the channel encoding and they…
Transmit Diversity mode in UMTS
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…
Work of Downlink Dedicated Physical Channel for 3G
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…
Emergence of Standards-Based Technology
In 1998, the Institute of Electrical and Electronics Engineers (IEEE) formed a group called 802.16 to develop a standard for what was called a wireless metropolitan area network, or wireless MAN. Originally, this group focused on developing solutions in the…
Spreading Technology in WCDMA
Spreading consists of 2 steps: Channelization operation, which transforms data symbols into chips Scrambling operation is applied to the spreading signal Spreading means increasing the bandwidth of the signal beyond the bandwidth normally required to accommodate the information. The spreading…
Spectrum Analysis of Spreading & Dispreading in WCDMA-3G
How Spreading & Dispreading in WCDMA-3G ? Traditional radio communication systems transmit data using the minimum bandwidth required to carry it as a narrowband signal. CDMA system mix their input data with a fast spreading sequence and transmit a wideband…