MIMO in wireless WAN — the UMB system

Theoretically, MIMO offers significant capacity benefits, but realizing these gains in deployed wireless systems remains a very challenging problem. MIMO has been used in wireless LAN systems with great success. However, due to the hugely varying spatial profiles and velocity patterns of the access terminals, integrating MIMO techniques in a wireless WAN system has been a difficult design problem. This paper introduces the design paradigms of ultra-mobile broadband, which is poised to become the successor of EVDO as the next generation of high speed wireless system. UMB allows the use of MIMO in various forms to suit the deployment scenario, and elicit as much gain as possible.

1 Introduction

Orthogonal Frequency Division Multiple Access (OFDMA) and multiple input multiple output (MIMO) have been among the most popular research topics for the last decade and many wireless industry standard bodies are investigating the OFDM-MIMO schemes which are the most efficient in the cellular environments ([1]has a good overview and references). This paper introduces the design paradigms of Ultra-Mobile Broadband (UMB), which is an OFDMA [2] system employing MIMO [3] for enhanced system performance. UMB is poised to become the successor of 1xEVDO [4] as the next generation of high speed wireless system in 3GPP2.