The dynamic adjustment of TDD UL DL configura tions to the instantaneous traffic conditions at small cells (e.g. Pico cells) in heterogeneous LTE networks can be used to further optimize the system performance. The dynamic adaptation of TDD configuration may result in opposite transmission directions in the neighboring cells and thus cause BS BS and UE UE inter cell interference that may significantly affect the overall system performance. To avoid this problem all homogeneous Macro cell TDD deployments typically operate synchronously. However in heterogeneous networks low power small cells are rather isolated from each other in terms of mutual interference and thus can be considered as candidates for dynamic TDD adaptation. In this paper we investigate the possibility of using dynamic adjustments of TDD UL DL configurations in application to outdoor Pico cell deployments. In particular, we show the feasibility of using oppo site DL and UL transmission directions in neighboring Pico cells in terms of interference environment. Furthermore we evaluate the performance benefits from traffic adaptation in LTE TDD networks where cells can dynamically select TDD configuration and show that substantial gains in packet throughput perfor mance may be achieved comparing to the traditional synchro nous TDD networks.

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We report on the preliminary design of W.M. Keck Observatory's (WMKO's) next-generation adaptive optics (NGAO) facility. This facility is designed to address key science questions including understanding the formation and evolution of today's galaxies, measuring dark matter in our galaxy and beyond, testing the theory of general relativity in the Galactic Center, understanding the formation of planetary systems around nearby stars, and exploring the origins of our own solar system. The requirements derived from these science questions have resulted in NGAO being designed to have near diffraction-limited performance in the near-IR (K-Strehl ~ 80%) over narrow fields (< 30" diameter) with modest correction down to ~ 700 nm, high sky coverage, improved sensitivity and contrast and improved photometric and astrometric accuracy. The resultant key design features include multi-laser tomography to measure the wavefront and correct for the cone effect, open loop AO-corrected near-IR tip-tilt sensors with MEMS deformable mirrors (DMs) for high sky coverage, a high order MEMS DM for the correction of atmospheric and telescope static errors to support high Strehls and high contrast companion sensitivity, point spread function (PSF) calibration to benefit quantitative astronomy, a cooled science path to reduce thermal background, and a high-efficiency science instrument providing imaging and integral field spectroscopy.

MAGIQ at the W. M. Keck Observatory: initial deployment of a new acquisition, guiding, and image quality monitoring system," Proc. SPIE 7014, Ground-based and Airborne Instrumentation for Astronomy II, 70141U (

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