Impact of the Gaussian Approximation on the Performance of the Probabilistic Data Association MIMO Decoder

A probabilistic data association based MIMO detector using joint detection of consecutive symbol vectors

“…A rate 1/2 convolutional code with polynomials (177, 133) is applied to introduce correlation across symbols. In order to demonstrate the error probability improvement brought by PDA-JD detector, which is far less obvious when entangled with channel decoder, we focus on the part from the input to the output of soft MIMO detector as shown in [6]and [7], and evaluate the bit error performance at the output of PDA-JD detector directly. This is a generally accepted manner in research of MIMO detectors.…”

“…High-quality probabilistic data offered by soft MIMO detector like PDA-JD detector is capable of giving more reliable a priori information to its following channel decoder in both receivers in [6]and [7], and thus helps reduce the total complexity accumulated through round by round iterations for the whole receiver. Additionally, for the straightforward serial receiver, the soft error decisions made by the soft MIMO detector flow into the after channel decoder and induce serious error propagation.…”

“…The seminal iterative receiver that combines MIMO detector and a soft-input soft-output channel decoder to accomplish joint detection and decoding [6] is investigated from this motivation. In practice, a more simplified receiver where MIMO detector and soft channel decoder are concatenated in a serial style without feedback [7] is often adopted.…”

A Novel Probabilistic Data Association Based MIMO Detector Using Joint Detection of Consecutive Symbol Vectors

“…The key feature of the conventional PDA algorithms in [1]- [4] is a repeated conversion of a multimodal Gaussian mixture probability structure, the true probability function for the noise and interference, to a single Gaussian with matched mean and covariance. Consequently, an implicit gap exists between the "Gaussian approximation" and the Gaussian mixture especially when the number of transmit antennas is small [7], with the result that the conventional PDA detectors are not generally near optimal. This is demonstrated by the simulation results for PDA under different modulation schemes in [1][2] and a theoretical proof in [8].…”

“…The improved quality of soft reliability information provided for the concatenated channel decoder by PDA-JD detector can not only help reduce the complexity of both the iterative and the straightforward sequential receivers, but also abate error propagation in the latter scheme. is a straightforward matter of adopting the non-decorrelated system model in [7] to the current problem). The received baseband signal at each instant of time is given by + y = Hx n , …”