Patent ID: 8385439

Claim:
A receiver, comprising: a vertical Bell Laboratories Layered Space-Time Architecture (V-BLAST) orthogonal frequency division multiplexing (OFDM) detector configured to receive input sequences and partially cancel polarization interference with respect to the input sequences to output symbol estimates for the input sequences, further including: performing a QR-factorization of Jones channel matrix H k =Q k R k and matrices C k and D k , where C k =diag −1 (R k )Q k † , and D k =diag −1 (R k )R k −I; removing estimated polarization interference from a received symbol vector {tilde over (r)} i,k =C k r i,k −D k {tilde over (s)} i,k ; and in an OFDM with coherent detection, representing a received symbol vector of the k th subcarrier in the ith OFDM symbol r i,k =[r x,i,k r y,i,k ] T by: r i,k =H k s i,k e j[φ CD (k)+φ T −φ LO ] +n i,k , where s i,k =[s x,i,k s y,i,k ] T denotes a transmitted symbol vector of k-th subcarrier in ith OFDM symbol, n i,k =[n x,i,k n y,i,k ] T denotes a noise vector dominantly determined by amplified spontaneous emission (ASE) noise; φ Γ and φ LO respectively denote laser phase noise processes of transmitting and local lasers, φ CD (k) denotes the phase distortion of the k th subcarrier due to chromatic dispersion (CD) (not considered here), and the Jones channel matrix H k ; one or more low-density parity-check (LDPC) decoders coupled to said V-BLAST OFDM detector though the a posteriori probability (APP) demapper, configured to receive channel bit reliabilities and output code words, the channel bit reliabilities being indirectly calculated from the symbol estimates in APP demapper and bit log-likelihood ratios (LLRs) calculator, the one or more LDPC decoders iteratively providing soft estimates to said APP demapper to improve the overall receiver performance.