Evaluation of MIMO Non- Stationarity
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The transmission performance of MIMO systems can be highly improved under stationary channel conditions where the channel statistics are constant. Unfortunately, mobile radio channels are not stationary all the time. Instead, they are stationary for finite time durations, so-called the stationarity regions. If these stationarity regions are relatively large, then the channel statistics can be utilized during each stationarity region to enhance the transmission performance. Therefore, it is necessary to examine the stationarity of mobile channels and characterize the stationarity regions. This thesis investigates the non-stationarity of measured MIMO channels and proposes some stationarity metrics to measure it. These metrics are: the CMD proposed by [1 ], NCMD and DES. Each one of the metrics is relevant to different types of transmission schemes and scenarios. The CMD may not be accurate for some transmission scenarios; therefore, the NCMD, which is a normalized version of CMD, is proposed. Theoretically, the NCMD can be at most 100% higher than the CMD for a 4x4 MIMO system. For beamforming scenario, the DES metric can be used to describe the non-stationarity of few eigenvectors taken from the channel variance. Under the measured MIMO channels, it was found that the CMD overestimates the stationarity regions compared to the NCMD and DES metrics particularly under the NLOS routes.
Place, publisher, year, edition, pages
2011. , 55 p.
EES Examensarbete / Master Thesis, XR–EE–SB 2011:005
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-53761OAI: oai:DiVA.org:kth-53761DiVA: diva2:470875
Subject / course
Master of Science - Wireless Systems
Bengtsson, Mats, Univ lektor