A FULL-RATE FULL-DIVERSITY 2×2 SPACE-TIME CODE FOR MOBILE WiMAX SYSTEMS

The recently developed IEEE 802.16e specifications for broadband wireless access include three multiple-input multiple-output (MIMO) profiles employing 2×2 spacetime codes (STCs) and two of those are mandatory on the downlink of Mobile WiMAX systems. One of these is full rate, and the other is full diversity, but neither of them has both of the desired features. The third profile, which is not mandatory, is both a full-rate and a full-diversity code, but it has a high decoder complexity. In this paper, we develop a full-rate full-diversity STC of size 2×2 which can be optimally detected at a substantially lower complexity than conventional schemes. This makes it a suitable candidate for future evolutions of WiMAX systems toward higher data rates and performance.