Detection Opportunities for CDM-OFDMA

In this paper, we present a synchronous code division multiplexing (CDM) scheme that uses orthogonal frequency division multiple access (OFDMA) to separate different users. The CDM component multiplies each data symbol with a different phase shift. This results in unique chips, which represent a new alphabet. The potential of this alphabet is shown by EXIT-charts. Therefore, the receiver can choose between an improved interference cancellation scheme as well as an iterative decoder. Latter does not rely on all chips of a spread sequence and increases the potential granularity of the CDM scheme