Coordinated MIMO Precoder EvaluationBased on Measurement in IndoorEnvironment
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
In this thesis, we investigate the performance of the coordinated MIMO precoders, using measured channels in indoorvenvironment. Instead of simulated radio propagationvconditions, measured channels are used to evaluate the precoder performance for real-world channels. Our measurement campaign includes several scenarios such as femtocell and “heterogeneous” networks. The study results illustrate that the precoders could reduce the interference significantly and support a high system throughput especially over high SNR where interference is dominant.
Degree of freedom (DoF) is defined as the maximum number of data stream that could independently coordinate to be transmitted interference-free. Theoretically, the precoders could support 1 DoF per user, while DoF of uncoordinated transmission is 0 per user. Interference Alignment(IA) study arises from information theory of DoF in the interference channel (IC). Three precoding algorithms are investigated to align the interference: maximum sum rate, maxSINR and minWLI. Considering the distributed precoder methods, “maxSINR” always performs better than “minWLI”. Since it tries to maximize the user’s SINR instead of only repressing the interference as “minWLI” does. While “maximum sum rate” is not good at finding an IA like solution that scales well at high SNR. However “maximum sum rate” converges faster than “maxSINR” and “minWLI”.
Our study about IA feasibility shows that precoding jointly over two subcarriers, using so called frequency extensions, allows 4 users to communicate interference-freeover a 2 × 2 MIMO IC. Without frequency extensions, only 3 users can communicate interference-free.
Place, publisher, year, edition, pages
2013. , 62 p.
EES Examensarbete / Master Thesis, XR-EE-SB 2013:004
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-121045OAI: oai:DiVA.org:kth-121045DiVA: diva2:616514
Subject / course
Master of Science - Wireless Systems
2013-02-18, 09:30 (English)
Bengtsson, Mats, Assoc. Prof.