Zaiqing Li

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We describe the design steps and final implementation of a MIMO OFDM prototype platform developed to enhance the performance of wireless LAN standards such as HiperLAN/2 and 802.11, using multiple transmit and multiple receive antennas. We first describe the channel measurement campaign used to characterize the indoor operational propagation environment,(More)
We present eecient polynomial time algorithms that place bn=2c vertex guards which cover the surface of an n-vertex polyhedral terrain, and similarly, bn=3c edge guards which cover the surface of an n-vertex polyhedral terrain. The time complexity of both algorithms, dominated by the cost of nding a maximum matching in a graph, is O(n 3=2).
We present an optimal ¢´Òµ-time algorithm for the selection of a subset of the vertices of an Ò-vertex plane graph so that each of the faces of is covered by (i.e. incident with) one or more of the selected vertices. At most ÒÒ¾ vertices are selected, matching the worst-case requirement. Analogous results for edge-covers are developed for two different(More)
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