CDMA Reference Blockset    
IS-95A Rev Ch Burst Randomizer

Generate a pseudorandom masking pattern of zeros and ones that can be used to mask redundant power groups

Library

IS-95A Mobile Station Transmitter

Description


This block generates a pseudorandom masking pattern of zeros and ones. The pattern can be used to mask redundant power groups in a data frame. The data rate and 14 bits from the long code determine the masking pattern.

Each 20-ms frame is composed of 16 power groups. The 14 long code bits that determine the data burst pattern for the current frame are the last 14 long code bits in the 15th power control group of the previous frame. Using these 14 bits and the algorithm specified in the IS-95A specifications, this block outputs a pattern that can select the valid power groups in each frame. The pattern contains a value of one in the positions that contain the valid power groups in a frame. Otherwise the pattern value is zero. The pattern will be an array of all ones for the full-rate Traffic channel.

Inputs

Rate
Integer scalar that specifies the data rate for the input signal. To indicate a rate fraction of Full, Half, Quarter, or Eighth, use an input value of 0, 1, 2, or 3, respectively. The table below shows all valid channel types and rate fractions, along with their associated data rates and Rate input values.

Channel Type
 Data Rate (bps)
 Input Value
Access (always Half rate)
 4800
 1
Traffic, Rate Set I, Full
 9600
 0
Traffic, Rate Set I, Half
 4800
 1
Traffic, Rate Set I, Quarter
 2400
 2
Traffic, Rate Set I, Eighth
 1200
3
Traffic, Rate Set II, Full
 14400
 0
Traffic, Rate Set II, Half
 7200
 1
Traffic, Rate Set II, Quarter
 3600
 2
Traffic, Rate Set II, Eighth
 1800
 3
Long Code
Binary vector representing the long code bit values. The vector size is a multiple of 256. The default size is 256.

Outputs

Binary vector representing a switch that indicates the power group validity. A value of one implies that a power group is valid and a value of zero implies that the power group is redundant. The vector output size is a multiple 16. The default value is 16.

Dialog Box

Parameters

Channel type
The channel type, either Access or Traffic.
Randomizer initial state
Real vector of size 16 that specifies the initial value of the randomizer's state. This gives the location of gated-off power groups in the first frame.

See Also

IS-95A Long Code Generator

Specification References

IS-95A 6.1.3.1.7.2
J-STD-008 2.1.3.1.7.2


 IS-95A Long Code Generator IS-95A Rev Ch Convolutional Encoder