Here You Get how 3G work, Go inside WCDMA Technology and wcdma rf optimization.
Different modulation methods corresponding to different transmitting abilities in air interface. R99/R4: QPSK HSDPA: QPSK or 16QAM The UTRAN air interface uses QPSK modulation in the downlink, although HSDPA may also employ 16 Quadrature Amplitude Modulation (16QAM). 16QAM requires good radio conditions to work well. As seen, with 16QAM also the amplitude of the signal … Read more
Logical Channel = information container Defined by is transferred. Transport Channel = characteristics of transmission Described by and with data is transmitted over the radio interface . Physical Channel = specification of the information global content providing the real transmission resource, maybe a frequency ,a specific set of codes and phase. In terms of protocol … Read more
Purpose of Channelization Code & Scrambling Code in WCDMA Purpose of Channelization Code & Scrambling Code in WCDMA Channelization Codes in WCDMA: Channelization codes, also known as Walsh codes, serve a critical purpose in WCDMA (Wideband Code Division Multiple Access) networks. These codes are used for the spreading of user data over a wide frequency … Read more
How Process Gain works in 3G? Process Gain = 10 Log (Chip rate/Bit Rate) Process gain differs for each service. If the service bit rate is greater, the process gain is smaller, UE needs more power for this service, then the coverage of this service will be smaller, vice versa. For common services, the bit … Read more
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 other spread symbols. In this figure, 4-digit codes are used. The product of the user … Read more
WCDMA Network Architecture The Wideband Code Division Multiple Access (WCDMA) network architecture: WCDMA (Wideband Code Division Multiple Access) is a 3G cellular network technology that operates on a wideband frequency and offers high-speed data and voice services. The WCDMA network architecture is based on two main components: the Radio Access Network (RAN) and the Core … Read more
A transmitted signal changes as it travels to the receiver. The effect of these changes is commonly referred to as fading. The fading results from the superimposition of transmitted signals, in which differences in attenuation, delay and phase shift have occurred. Slow fading: In case shadow effect is caused by obstacles, and the receiving signal … Read more
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 10GHz to 66GHz band, with the primary application being delivering high-speed connections to businesses that … Read more
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 process in UTRAN consists of two separate operations: channelization and scrambling. The first operation is … Read more
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 signal. The spreading sequence is independently regenerated at the receiver and mixed with the incoming … Read more