IS-95A Rev Ch Walsh Modulator (CDMA Reference Blockset)

Modulate the input data sequence with the Walsh codes

Library

IS-95A Mobile Station Transmitter

Description

This block modulates the input data bits with the Walsh codes. If M = 2^W and W is the Walsh order parameter, then the block performs an M-ary orthogonal modulation. This process maps W input bits to one modulation symbol. One of the 2^W possible modulation sequence is transmitted for each input symbol. The modulation symbol is represented as a sequence of 2^W bipolar values. The 64-ary modulation sequences for Walsh order equal to 6 are given in a table in the IS-95A specification.

Inputs

Binary vector representing the input data sequence to be modulated. The size of the input vector is a multiple of W. The default vector size is 6.

Outputs

Real vector of bipolar data representing the Walsh code modulated data sequence. The size of the output vector is a multiple of 2^W. The default vector size is 64.

Dialog Box

Parameters

Walsh order: Integer scalar that specifies the order of the output Walsh code and therefore the corresponding modulation scheme.
Input vector length: Integer scalar that specifies the number of bits in the input. Since these bits are to be mapped to modulation symbols, this should be an integral multiple of the Walsh order parameter.

Specification References

IS-95A 6.1.3.1.6
J-STD-008 2.1.3.1.6

IS-95A Rev Ch Walsh Modulation and Spreading IS-95A Short Code Generator