Performance of a nonlinear adaptive SBS-MAP detector usingsoft-statistics for digital transmissions over HF channels

摘要

The effectiveness of the adaptive maximum a posteriori (MAP)nreceiver in Cusani and Mattila is verified for digital HF links betweennmobile and/or fixed units. Following Cusani and Mattila (1998), ansuitable MAP algorithm is employed to compute symbol-by-symbol (SBS) thena posteriori probabilities (APPs) of the channel state; from these, thendetected data stream is obtained. The same APPs are employed by annadaptive nonlinear Kalman-like filter to estimate recursively thentime-varying channel with fast convergence and good tracking properties,novercoming the delay problem suffered by conventional adaptive MLSE-VAndetectors. Computer simulations allow to compare the adaptive SBS-MAPnwith other receivers (DFE, MLSE) and verify its effectiveness in the HFnenvironment