Spectral shaping is one of the primary technical challenges in spectrally constrained multiple access applications. In this paper, we introduce an efficient orthogonal CDMA-based spectral shaping technique. In our approach, termed Code- Hopping CDMA, users are allowed to hop between available spreading codes in an orthogonal fashion with different frequencies. We show that code hoping patterns can be chosen such that the power spectral density of the resulting signal would approximate a predetermined desired shape. We will demonstrate our approach through two examples and analyze the impact of the hopping pattern on the system capacity.

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