A Novel Subspace Decomposition-Based Detection Scheme with Soft Interference Cancellation for OFDMA Uplink

In this paper we propose a novel subspace decomposition-based detection scheme with the assistance of soft interference cancellation in the uplink of interleaved orthogonal frequency division multiple access (OFDMA) systems. By utilizing the inherent data structure, the interference is first separated with the desired symbol and then further decomposed into the one caused by the residues of decision errors and the other one by the undetected symbols in the successive interference cancellation (SIC) process.With such an ingenious interference decomposition along with the soft processing scheme, the new receiver can render more thorough interference cancellation, which in turn entails enhanced system performance. Moreover, for practical implementations, a low-complexity version, which only deal with the principal components of inter-carrier interference (ICI), is also addressed. Conducted simulations show that the developed receiver and its low-complexity implementation can provide superior performance compared with pervious works and is resilient to the presence of carrier-frequency offsets (CFOs). The low complexity implementation, in particular, requires substantially lower computational overhead with only slight performance loss.