A novel assisted near-ideal joint decision feedback equalizer for MIMO spatial multiplexing

In this paper, a novel joint decision-feedback equalizer (DFE) with progressive group detection (PGD) assistance is proposed for downlink MIMO spatial multiplexing systems under frequency-selective fading channels. The proposed DFE operates on chip-level to accommodate CDMA wideband systems employing short and long scrambling codes over frequency-selective channels. PGD is a near-maximum likelihood (ML) detection technique that spans and intelligently prunes the set of possible transmit-symbol combinations, and provides a set of the most probable combinations as interim hypotheses for symbol-decisions to the DFE, replacing the simplistic decision device in order to circumvent the initial chip-decisions availability problem of CDMA systems and mitigate the infamous error propagation effect due to faulty feedback. Simulation results for the 3GPP TD-HSPA Evolution (TD-HSPA+) employing MIMO spatial multiplexing show that the proposed receiver outperforms joint block linear equalizers and DFE receivers found in literature, and provides performance gains that scale with complexity.