Yu Shuan Yeh

Outdoor BLAST measurement system at 2.44 GHz: calibration and initial results

There are ever increasing demands for additional capacity in wireless communications to handle voice, data, and wideband Internet applications. These demands are constrained by the bandwidth that was allocated to wireless communications. The spectral efficiencies in present day wireless systems hover around 1 bit/s/Hz. Bell-labs Layered Space-Time (BLAST) is a communication technique for achieving very high spectral efficiencies in highly scattering environments using multiple transmit and receive antennas. A measurement campaign was undertaken to assess the BLAST gains in spectral efficiency in the suburban outdoor environment for stationary subscribers. The measurements employed directive antennas to better control interference from adjacent cells. The measurements were performed over a narrow band at 2.44 GHz with five transmitting and seven receiving antennas, respectively. Extensive calibration methods, assisted by simulations, were developed to assure accurate results for the BLAST capacities of the measured remote subscriber sites. Initial results indicate that BLAST capacities of C/sub B//spl ges/38 bits/s/Hz at 20% of the measured locations and C/sub B//spl ges/24 bits/s/Hz at 50% of these locations are feasible, for reasonable link parameters and negligible interference.

BLAST system capacity measurements at 2.44 GHz in suburban outdoor environment

There are ever increasing demands, in wireless communications, for additional capacity to handle voice, data and wideband Internet applications. These demands are constrained by the bandwidth that has been allocated to wireless communications. A novel unorthodox concept to substantially increase the spectral efficiency in highly scattering environments, named BLAST (Bell-labs LAyered Space-Time), has been introduced (see Foschini, G.J., Bell Labs Technical Journal, vol.1, no. 2, p.41-59, 1966; Foschini, G.J. and Gans, M.J., Wireless Personal Communications, vol.6, p.311-35, 1998). A measurement campaign was undertaken to assess the BLAST gains in spectral efficiency in the suburban outdoor environment for stationary subscribers. The measurements employed directive antennas for better control of interference from adjacent cells. Extensive calibration methods, assisted by simulations, were developed to assure accurate results for the BLAST capacities of the measured remote subscriber sites.