Low complexity interleaved sub-carrier allocation in OFDM multiple access systems

In multicarrier (MC) systems, a possible multiple access scheme is obtained by assigning a disjoint set of sub-carriers to different users. If a user is assigned a set of maximally spaced sub-carriers, then we have an interleaved assignment. This approach is particularly interesting because of the possible independency among the sub-carriers allocated to a single user. We propose a new method to carry out an interleaved sub-carrier assignment efficiently in MC frequency division multiple access (FDMA) systems. According to the conventional approach, the assignment of the sub-carriers to the different users is accomplished prior to the MC modulation that is performed over all the sub-carriers within the bandwidth. The proposed method enables the MC modulation/demodulation of only the sub-carriers really assigned to a specific user, thus becoming much simpler to implement than the conventional approach.