TECH DIGITAL RESOURCE LIBRARY

DoCoMo Euro-Labs


Latest Content From DoCoMo Euro-Labs

Whitepaper: Context-Aware Wireless Ubiquitous Computing

by DoCoMo Euro-LabsJan 01, 2008

Context-aware computing is one technology to support wireless ubiquitous computing as it enables services and applications in the wireless communication environment to benefit from environmental information. In particular, context aware computing describes a paradigm, where an application uses knowledge related to a set of environmental states and settings to determine and adapt the applications behavior. This paper describes an architecture supporting context aware computing in wireless ubiquitous computing environments based on the concept of context spaces as virtual meeting points for communities of ubiquitous computing peers.


Whitepaper: Space-Time-Frequency Transmit Diversity in Broadband Wireless OFDM Systems

by DoCoMo Euro-LabsJan 01, 2008

This paper published by DoCoMo Euro-Labs considers space-time - frequency transmits diversity with orthogonal designs in a broadband OFDM system. On capacity considerations for Gaussian as well as real world signal constellations, it show that the concatenation of an outer error control code, a bit interleaver and orthogonal spatial transmit diversity provides an attractive MIMO scheme which is robust to channel imperfections such as spatial correlation. It proposes an application of orthogonal designs for space-time-frequency transmit diversity and give design criteria which allow using a simple combiner at the receiver also in time-varying and severely frequency-selective channels.