An efficient approach for designing filter banks for Multi-Carrier Transmission

This paper proposes a fast design scheme for optimizing a novel family of multi-carrier transmission (MCT) systems that are built up based on critically-sampled cosine-modulated filter banks (CMFBs). This approach extends an earlier-proposed windowing-method (WM)-based technique for optimizing prototype filters for CMFBs such that, in addition to the cut-off frequency of the ideal filter, three terms in a four-term window function are used as unknowns, thereby leading to an optimization problem with only four adjustable parameters. Such an optimization problem is very efficiently solvable also when long prototype filters and many subchannels are required. What makes the resulting MCT systems novel is that the optimization concentrates on minimizing directly a weighted sum of the inter- symbol and inter-channel interferences in these MCT systems, without directly considering the prototype filter. If the weight values in this sum are fixed, then the values of the unknowns can be optimized for the given overlapping factor. After tabulating these values, a closely optimum solution for any number of channels is obtained by simply using the WM together with these tabulated values.