STANAG 4444: Improved soft-decision detector for the spread spectrum mode

This contribution results from the implementation of the physical layer of the STANAG 4444. Two operation modes are available in the STANAG 4444, namely the EEWF and DSWF. The performance of each mode has been evaluated making special emphasis in the DSWF one which uses Direct-sequence Spread-spectrum for symbol modulation. In order to accomplish with the specifications dictated by the norm in terms of Bit Error Rate and Frame Error Rate for various CCIR recommended channels, several approaches have been studied. Through the evaluation of the different strategies soft-decision decoding became a suitable solution in order to grant a proper performance.