Tag Archives: cdma

CDMA Variable Rate Speech Coder

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

Why Closed Loop Power Control in CDMA

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

Open Loop Power Control in CDMA

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

How Power Control in Reverse Link in CDMA ?

Power Control Required in Reverse link cdma due to following reason. Maximum System Capacity is Achieved if: All Mobiles are Power Controlled to the Minimum Power for Acceptable Signal Quality

EVDO reverse Link

Here I write about EVDO (HSD) reverse channel in short or summarize defination. The reverse link for 1xEV-DO has a structure similar to that for CDMA2000. In EV-DO all signalling

EV-DO forward link in short

The forward link possesses many features that are specific to EV-DO, having been optimised for data transmission, particularly in the downlink direction. Average continuous rates of 600 kbps per sector

Forward link EVDO channels in Detail

A number of channels are transmitted in the forward direction to enable signalling, data and other capabilities to be handled. These channels include the Traffic channel, MAC channel, Control channel

Mobile Power Bursting in CDMA

Each 20 millisecond frame in EIA/TIA-95-B CDMA is divided into sixteen “power control groups”. When the mobile transmits, each power control group contains 1536 data symbols (chips) at a rate

Base Station Variable Rate Vocoder

The base station uses a slightly different scheme when the vocoder moves to lower rates. First, EIA/TIA-95-B CDMA base stations do not pulse their transmissions. Rather, base stations repeat the

CDMA Vocoders how and why

Vocoders Convert Voice to/from Analog Using Data Compression There are Three CDMA Vocoders: IS-96A  Variable Rate (8 kbps maximum) CDG  Variable Rate (13 kbps maximum) EVRC  Variable Rate (improved 8

How Frame Formats in CDMA

Once the analog voice is compressed by one of the vocoder processes, some additional data is added to produce a frame. Each frame in CDMA is 20 milliseconds regardless of