It is also explained how this loss can be compensated for by combining time-domain detection with frequency-domain interference cancelation.
If the target signal and the interference are overlapped in the frequency domain, the interference can also be suppressed by using the oblique projection operator.
Clearly, by precoding in the frequency domain, the interference leakage will depend on the delays between transmitters and receivers, and hence there will be some residual interference when the interfering symbols are not aligned in time with the receiver window.
Two multi-user IB-DFE-based processing schemes are considered, both with the feedforward and feedback filters designed in space frequency domain: iterative successive interference cancellation (SIC) and parallel interference cancellation (PIC).
In (6), the log function contains only σ2 in the denominator due to the use of an interference model, which ensures that when node i is transmitting to node j on band m, the interference from all other nodes in this band must remain negligible due to the frequency domain scheduling and interference constraints.
The rest of the constraints, i.e., frequency domain scheduling, power, and interference constraints, are the same as those posed for BRR, with M q replaced by M (17).
Suppressing interference in time domain and frequency domain fundamentally involves estimating parameters of interference and then suppressing, with iterative algorithm widely employed, like least-mean-square filters [11, 12] and orthogonal subspace projection filtering [13].
Because in the previous section we assumed that each interference superposes on at least two consecutive subcarriers of the desired OFDM symbols in frequency domain, we can estimate each interference power accurately by averaging procedure in Eq. (12).
The structure of matrix reveals that the interference affects only the first samples of the time-domain OFDM symbol, hence the interference in frequency domain will be highly correlated.
