Virtual MIMO performance in a measured outdoor-to-indoor cellular scenario

Allowing users in a wireless system to collaborate to form a virtual multi-antenna link can reduce hardware complexity and result in improved propagation conditions, which can lead to link performance enhancements. However, the local propagation conditions at the collaborating users can in some cases result in a performance loss, so it is important to understand how often in a given environment the benefits of a virtual MIMO system are available. This paper presents results from a 4×4 outdoor-to-indoor MIMO propagation measurement campaign showing how often capacity, K-factor, and correlation are improved when two users collaborate, and establishes the likelihood that a given parameter value can be improved upon through the action of virtual MIMO.