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Gold sequence generator block





Gold sequence generator is a class of pseudorandom generator which has good randomness properties to decrease the multiple access noise found in multi-user DS-CDMA communication systems. It is composed with two Maximal Length Liner Shift Register (MLLSR) sequence generator. Most properties of this registers can be found in [1]. An example of block diagram of Gold sequence generator with 5-length MLLSR is shown in Fig. 1.

Figure 1: Gold sequence generator

Each clock time, the registers shift all elements to the right. The following general equation gives the output of a Gold generator:

c_{n}&=&{\displaystyle \sum_{i=1}^{r}Ca_{i}a_{n-i}+\sum_{i=1}^{r}Cb_{i}b_{n-i}}.

$ a_{n}$ and $ b_{n}$ are the outputs of the MLLRS, $ Ca_{i}$ and $ Cb_{i}$ are the corresponding connection variables and $ r$ the length of registers. All terms are binary, meaning that adders are realized with the boolean exclusive-OR operator. In fact, each register needs only two integer value to be processed (one value for states and one value for connections). In that block, all operations -modulo-2 adders, shifts- are realized with the binary operators of C language that ensures fast dynamical computation.

Dialog box


Default properties

Interfacing function

Computational function

See also


A. Layec


[1] A. J. Viterbi, Principles of Spread Spectrum Communication.Addison-Wesley, 1995.