Code and frequency acquisition for fully digital CDMA-VSATs

A concept for joint code and carrier frequency acquisition in fully digital low-cost CDMA-VSATs (code division multiple access very small aperture terminals) is presented and substantiated by performance analyses. Minimum cost and complexity have been driving design issues and are achieved by fully digital signal processing. Performance has been evaluated by means of 98%-confidence limit computations using a receiver model based on fundamental theorems of multirate signal processing. It has been found that the acquisition concept can accommodate large frequency errors and that dramatic improvements can be obtained by slightly increasing E_I/N₀ . Thus, in the absence of data modulation acquisition can be speeded up by increasing the coherent integration time in multiples of the code period