How to perform OQPSK modulation

Hi all, I am trying to modulate a PN spread data bits using OQPSK. I have delayed the Q-phase stream by half the chip period(that is, by up sampling by 2 and then shifting the Q-phase stream by a delay element), but don't know, how to map these stream to symbols. Is there any lookup table for the same?

Any help is highly appreciated.

Answer 1

[Tasos Giannoulis]

1) You can use the oqpskmod function or the comm.OQPSKModulator System object (and the corresponding block) from the Communications System Toolbox. These tools will produce the symbols for you.

2) Alternatively, you can map the unipolar bits [0, 1] to a bipolar signal [-1 -1], using this command: >> bipolarSignal = bits*2-1; Then you can follow what you have been doing so far and all that remains is to scale the constellation to your liking, e.g., by sqrt(2)/2.