CDMA Reference Blockset    
IS-95A Fwd Ch Repeater/Derepeater

Repeat, puncturing if necessary, or derepeat the symbols of the encoded frame

Library

IS-95 Base Station Transmitter

Description


This block repeats or derepeats the convolutionally encoded frame symbols for the forward channel. While repeating, the block also punctures the data if necessary.

For the Paging and Traffic channels and in repeater operation mode, this block repeats the convolutionally encoded symbols prior to block interleaving whenever the information rate is lower than full rate. In the half rate, quarter and one-eighth data rate modes of operation, each symbol repeats once, three and seven times, respectively. In Rate Set I, the repetition operation results in a frame size of 384 symbols for all data rates. For Rate Set II, the repetition operation results in a frame size of 576 symbols for all data rates, but the repeated data is punctured before leaving the output port. The puncturing pattern deletes the third symbol in a group of three symbols while retaining the first and the second symbols. After puncturing, the output frame size is 384 symbols.

For the Sync channel in repeater operation mode, the block repeats each symbol once. Therefore, each output frame consists of 128 symbols.

The derepeater inserts zeros in the positions of the punctured symbols and averages over the repeated data symbols.

For repeater operation mode, the input and output frame sizes equal 576 and 384, respectively, in Paging and Traffic channels. For the Sync channel, the input frame size is 576 and the output frame size is 128.

For derepeater operation mode, the output port size is the maximum possible size of 576 (Rate Set II, Traffic Full Rate). The following table shows the number of relevant bits at the input of the repeater and output of the derepeater, for each channel type and data rate.

Channel Type
 Number of Relevant Bits for Repeater Input and Derepeater Output
Sync
 64
Paging, Full Rate
 384
Paging, Half Rate
 192
Traffic, Rate Set I, Full Rate
 384
Traffic, Rate Set I, Half Rate
 192
Traffic, Rate Set I, Quarter Rate
 96
Traffic, Rate Set I, Eighth Rate
 48
Traffic, Rate Set II, Full Rate
 576
Traffic, Rate Set II, Half Rate
 288
Traffic, Rate Set II, Quarter Rate
 144
Traffic, Rate Set II, Eighth Rate
 72

Inputs

Rate
Integer scalar that specifies the data rate for the input frame. 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
Sync (always Eighth rate)
 1200
 3
Paging, Full
 9600
 0
Paging, Half
 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
Frame In
For repeater operation mode, this is a binary vector of size 576 representing the convolutionally encoded data. For derepeater operation mode, this is a real vector of size 384.

Outputs

For repeater operation mode, this is a binary vector of size 384 (128 for the Sync channel) representing the output frame. For derepeater operation mode, this is a real vector of size 576.

Dialog Box

Parameters

Rate set
The rate set, either Rate Set I or Rate Set II.
Channel type
The channel type, either Sync, Paging, or Traffic.
Function
Repeater or Derepeater.

See Also

IS-95A Rev Ch Repeater/Derepeater
IS-95A Forward Traffic Channel Codec Demo

Specification References

IS-95A 7.1.3.1.4
J-STD-008 3.1.3.1.4


 IS-95A Fwd Ch Rake Finger IS-95A Fwd Ch Scrambler