Tag: 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…

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…

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…

There are Four channel in Forward direction in cdma. PILOT CHANNEL (1) SYNC CHANNEL (1) FORWARD TRAFFIC + PAGING CHANNELS (62) PAGING CHANNELS ( MAXIMUM 7) PILOT CHANNEL PILOT SIGNALS…

Diversity Reception: Multiple Antennas at Base Station Each Antenna is Affected by Multipath Differently Due to Their Different Location Allows Selection of the Signal Least Affected by Multipath Fading If…

Vocoders Human voice is made up of a combination of voiced and unvoiced sounds Vocoders exploit these properties of speech production mechanism Vocoders do not respond to music, non-human sounds…

IP Networks use Routers to do the switching based on IP addresses, Layer 3 routing protocols like BGP or OSPF an Ethernet networks use 48 bit MAC addresses Spanning Tree…

CDMA takes advantage of quiet times during speech to raise capacity.  A variable rate vocoder is used; for the original vocoder the channel is a 9,600 bps when the user…

Closed loop power control is used to allow the power from the mobile unit to deviate from the nominal as set by open loop control. This is done with a…

The Open Loop Power Control require in cdma due to following reason. Assumes Loss is Similar on Forward paths and Reverse Paths Receive Power + Transmit Power = -73 All…