Analysis of Wide-Band MIMO Measurements for the 60 GHz Band

摘要

Multiple Input Multiple Output (MIMO) channel measurements at 60 GHz, both indoors and outdoors, are analyzed in this paper from two perspectives. First, we consider the single- carrier, single stream case. 2x2 MIMO measurements over a 2.2 GHz bandwidth are used to generate 4 times the number of Single Input Single Output (SISO) channels. These measurements are then used to quantify the performance improvements from the use of a decision feedback equalizer (DFE) instead of a linear equalizer (LE) to corroborate previous results based on raytracing simulations which had indicated that even with beam-formed transmission and reception, a single carrier system can benefit from the use of a DFE. In this paper we extend that simulation work to actual measurements at 60 GHz made both indoors and outdoors and demonstrate that in real-world channels significant performance improvements can indeed be realized using a DFE. Second, we analyze the 2x2 MIMO capacity as a function of beam orientation and demonstrate, again with real measurements, that in many cases the beam orientation that maximizes total received power is also that which maximizes MIMO capacity, and in cases where that is not the case the capacity is reduced by only about 4.5%. Thus, simpler power maximization algorithms can be used instead of more complex capacity maximizing algorithms for beam tracking, with very little performance degradation.