LTE MIMO Types of Inputs and Outputs

LTE MIMO “input” and “output” are used for medium between transmitters and receivers, including both RF components – known as the “channel”. Thus, the base station with two transmitters provides two inputs to the channel, “mi” page, and the handset takes two strings get two out of the chains, “MO” part. It is only when […]

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How Open-Loop Transmit Diversity in Wimax?

Transmit spatial diversity is a newer phenomenon than receive diversity and has become widely implemented only in the early 2000s. Because the signals sent from different transmit antennas interfere with one another, processing is required at both the transmitter and the receiver in order to achieve diversity while removing or at least attenuating the spatial […]

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Interference Limited MIMO Systems for Wimax

The third assumption—that the background noise is Gaussian and uncorrelated with the transmissions—is especially suspect in a cellular MIMO system. All well-designed cellular systems are by nature interference limited: If they were not, it would be possible to increase the spectral efficiency by lowering the frequency reuse or increasing the average loading per cell. In the […]

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Interference Limited MIMO Systems for Wimax, cellular mimo, interference problem, interference aware, mimo systems, spatial multiplexing, transmit antennas, cell interference

CDMA Forward Channel Carrier Power

CDMA forward channel carrier power varies greatly depending on how many traffic channels are in use, the characteristics of the users voices, the Forward Power Control settings as requested by each subscriber unit in use, and the power allocated for overhead functions (Pilot, Page and Sync). An approximation of the CDMA forward channel carrier power […]

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CDMA Forward Channel Carrier Power, average traffic, forward channel, pilot power, power level, softer handoff, carrier power, channel power, forward power, traffic channels, power control

What is Antenna Beamwidth ?

Antenna beamwidth is measured in degrees between the half power points (3 dB) of the major lobe of the antenna, Beamwidth can be expressed in terms of azimuth (horizontal or H-plane) and elevation (vertical or E-plane). The predominant type of antenna configuration within urban areas at PCS frequencies will be three sectored. This implies that […]

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Antenna Beamwidth, beamwidth, antenna, coverage, horizontal, sectors, degrees, traffic, predominant, parameters

Work of Acquisition Indicator Channel AICH in 3G

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 […]

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Work of Uplink Dedicated Physical Channel in WCDMA

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 […]

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Work of Uplink Dedicated Physical Channel in WCDMA, uplink dpdch, dedicated physical, pilot tfci, ovsf code, frame structure, dpcch time

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 the TFCI field. TFCI bits are not used for fixed rate services or when the […]

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Downlink Dedicated Physical Channel for 3G, dpdch, uplink, downlink, multiplexed, physical channel 3g, 3g physical, 3g channel

Global Positioning System – GPS

The Global Positioning System (GPS) is a radio-navigation system that employs RF transmitters in 24 satellites. The satellite configuration when completed will guarantee that a GPS receiver located anywhere on earth can receive RF signals from at least four satellites 24 hours a day (with unobstructed visibility). For commercial use, each satellite transmits unique bi-phase […]

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Global Positioning System, gps receiver, gps system, satellites, gps location, gps how works, gps system, global positioning

How Antenna Downtilting selection for cdma ?

Downtilting is the method of effectively adjusting the vertical radiation pattern of the antenna to increase the amount of power radiated downwards. Downtilting can be used to increase the amount of coverage close to the site where “nulls” (holes) may exist due to the effective height of the antenna. Downtilting can also be used to […]

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antenna downtilt, antenna, vertical, system engineer, downtilting, vertical radiation, vertical beamwidth, electronic downtilt

Voltage Standing Wave Ratio and Return Loss

Voltage Standing Wave Ratio Voltage Standing Wave Ratio (VSWR) is another parameter used to describe an antenna performance. It deals with the impedance match of the antenna feed point to the feed or transmission line. The antenna input impedance establishes a load on the transmission line as well as on the radio link transmitter and […]

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impedance of the antenna, vswr in gsm, vswr in cdma, vswr, return loss, loss of cable, antenna performance, transmission line impedance

Vocoder: A Voice Compression in CDMA

When we talk, we pause between syllables and words. CDMA takes advantage of these pauses in speech activity. Analog to digital conversion The voice signal is converted to a digital signal using PCM. Variable rate vocoder The vocoder (Voice Coder) is used to compress the digital signal from the Codec (Code/Decode). The vocoder, used in […]

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