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Three 3G ,PULSERA NEGRA CON ARGENTINA
domestic production - China Mobile TD-SCDMA, China Unicom WCDMA,PULSERA AZUL CON LOGO XB, China Telecom CDMA2000
1st 3G product of the elementary parameters
1. the whole of China Mobile TD-SCDMA is called Time Division-Synchronous CDMA (time division synchronous CDMA)
RTT TDD-CDMA system, a GPS chip rate bandwidth of 1.6Mhz to 1.28Mcps nation band 1880-1920,2010-2025 Mhz

2. The full label of China Unicom's WCDMA Wideband CDMA
RTT FDD asynchronous CDMA system, no GPS chip rate bandwidth for the 3.84Mcps 5Mhz country band 1920-1980/2110-2170/1755-1785/1850-1880Mhz
3. China Telecom CDMA2000 technology is amplified from the narrow-band CDMA IS95 CDMA technology for broadband
RTT FDD-CDMA system has a GPS chip rate bandwidth 1.23Mhz 1.2288Mcps country band 1920-1980/2110-2170/1755-1785/1850/1880Mhz

comparison:
WCDMA TD-SCDMA CDMA2000 can be provided in the stationary state 2Mbit / s data transmit rate,PULSERA BLANCA CON MEXICO, the 3 key technologies there are colossal differences in performance are also different.

1. chip rate and carrier bandwidth
TD-SCDMA uses 1.28Mchip / s of the chip rate, using TDD duplex mode, because it is so time-full-duplex mode only for the occupation of a single 1.6M O bandwidth can mail 2Mbit / s file services . The WCDMA and CDMA2000 to send 2Mbit / s file services necessitate 2 symmetrical bandwidth. TD-SCDMA and thus the utilization of frequency resources is the maximum.

WCDMA (FDD-DS) means using straight sequence scatter spectrum, chip rate is 3.84Mchip / s. CDMA20001X and CDMA20003x difference is the number of another carriers, 1x single conveyor, chip rate is 1.2288Mchip / s,PULSERA AZUL CON BANDERA, CDMA20003x for the three-carrier chip rate 1.2288 * 3 3.6864Mchip / s. Chip rate frequency-selective use of energy-efficient and space diversity receive and transmit diversity, can mainly solve the problem and the multipath fading problem. Carrier bandwidth is high, the extra the number of consumers supported in the communication the likelihood of congestion on the small. WCDMA in this regard has apparent avails.

2. duplex mode
WCDMA and CDMA2000 are using FDD (frequency division digital duplex) mode, TD-SCDMA is the color accustomed in TDD (time division digital duplex) mode
FDD into the frequency, the downlink symmetry operations
TDD is the transmission of upwards and downstream duplex mode using the same frequency orchestra, according to the period apt distinguish between up and down the line and switch
TDD spectrum efficiency high and costs low, but non-consecutive multi-slot transmission mode, the found station transmitter pinnacle power and average power ratio higher, resulting in higher power bottom stations, base station coverage radius is small, also result in anti-fading and anti-poor performance of Doppler shift, when the mobile apparatus when in a state of high-speed mobile communications meager.
WCDMA and CDMA2000 can assist mobile devices is about 500 km per hour while in the regular communication,PULSERA BLANCA CON NETHERLANDS, and TD-SCDMA mobile extremities can merely support approximately 120 kilometers per hour, ashore the expressway and railroad and other high-speed mobile context by a disadvantage in the TD-SCDMA .

other narrated technologies such as the antenna. . . Handoff technology, time afterward time to write. . . Hey ~~~~
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