Cyclic prefix and intra-fix insertion for multi-h CPM based on tilted phase transformation

This paper addresses the problem of cyclic prefix insertion for multi-h CPM waveforms. Like single-h CPM, the memory inherent in a multi-h CPM waveform, and its continuous nature, requires the use of an intra-fix in each transmitted block. We identify the structure of the block, the constraints on its length, and the symbols of the intra-fix. A procedure is proposed for finding the symbols of the intra-fix using the tilted phase transformation. The procedure ensures that the overhead due to the intra-fix is minimized. Bounds on the intra-fix length are also presented in terms of parameters of the modulation scheme. The proposed procedure is applied on a dual-h CPM scheme for illustration of analytical results.