SIR in the WCDMA system corresponds to the ratio of the received useful signal at the base station receiver over a frequency range of 5 MHz width compared to interfering co-channel sources. In the uplink, received useful signal at the base station receiver is signal from the mobile station.
What is Sir in UMTS?
The SIR indicates the ratio between the received signal level and the level of interference. This parameter is used in WCDMA systems to control transmission power of user equipment (UE).
What power control mechanism is used in WCDMA?
Power control in WCDMA is a closed-loop PC which is a combination of outer and inner closed loop control (see Figure 1). The inner (also called fast) closed loop PC adjusts the transmitted power in order to keep the received Signal-to-Interference Ratio (SIR) equal to a given target.
Why power control is used in umts?
Fast power control is important in keeping interference to a minimum and improving capacity. Without it, transmit power would have higher to meet quality targets. The gain from this control is as much as 5.8 dB at the receiver for pedestrian speeds for 8kbps speech with 10ms interleaving and antenna diversity.
What is power control in UMTS?
Contact Us. UMTS Power Control. Open loop power control is the ability of the UE transmitter to sets its output power to a specific value. It is used for setting initial uplink and downlink transmission powers when a UE is accessing the network.
Which codes are used to spread the signal in Wcdma?
The codes required to spread the signal must be orthogonal if they are to enable multiple users and channels to operate without mutual interference. The codes used in W-CDMA are Orthogonal Variable Spreading Factor (OVSF) codes, and they must remain synchronous to operate.
Why is power control used in Wcdma and CDMA 2000?
The power control in cdma 2000 and WCDMA is to minimize interference due to presence of other mobile users, fading, log normal shadowing as well as from fast Rayleigh fading. viii. In cdma2000, power control is at the rate of 800Hz in both the links and it is at a rate of 1500Hz in both the links in WCDMA.
What is inner loop control?
Inner loop power control in the uplink is the ability of the UE to adjust its output power in accordance with one or more TPC (transmit power control) commands received in the downlink. The UE’s output power changes in response to a single TPC command, TPC_cmd, derived at the UE based on the power control algorithm.
What is spreading factor in Wcdma?
WCDMA uses Direct Sequence spreading, where spreading process is done by directly combining the baseband information to high chip rate binary code. The Spreading Factor is the ratio of the chips (UMTS = 3.84Mchips/s) to baseband information rate. Spreading factors vary from 4 to 512 in FDD UMTS.
What is the bandwidth of one channel of Wcdma is?
3.84 MHz
WCDMA specifications summary
| WCDMA Summary | |
|---|---|
| Parameter | Details |
| Transmitted symbol rate | 3.84 Msps |
| Signal bandwidth | 3.84 MHz |
What is the modulation technique used by WCDMA technology?
W-CDMA is a spread-spectrum modulation technique; one which uses channels whose bandwidth is much greater than that of the data to be transferred.
What is difference between CDMA and WCDMA?
The main difference between CDMA and WCDMA is that CDMA is an algorithm that beings more channels in a single bandwidth, while WCDMA uses CDMA and incorporates GSM and EDGE in it. CDMA is used over a 2G network, while WCDMA is used over a 3G network. CDMA is slow compared to WCDMA.
