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A system consisting of an antenna array and an adaptive processor can perform filtering in both the space and the frequency domains, thus reducing the sensitivity of the signal-receiving system to interfering directional noise sources. Variable weights of a signal processor can be automatically adjusted by a simple adaptive technique based on the least-mean-squares (LiVIS) algorithm. During the adaptive process an injected pilot signal simulates a received signal from a desired "look" direction. This allows the array to be "trained" so that its directivity pattern has a main lobe in the previously specified look direction. At the same time, the array processing system can reject any incident noises, whose directions of propagation are different from the desired look direction, by forming appropriate nulls in the antenna directivity pattern. The array adapts itself to form a main lobe, with its direction and bandwidth determined by the pilot signal, and to reject signals or noises occurring outside the main lobe as well as possible in the minimum meansquare error sense. Several examples illustrate the convergence of the LMS adaptation procedure toward the corresponding Wiener optimum solutions. Rates of adaptation and misadjustments of the solutions are predicted theoretically and checked experimentally. Substantial reductions in noise reception are demonstrated in computer-simulated experiments. The techniques described are applicable to signal-receiving arrays for use over a wide range of frequencies.

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Broadcasting protocols for video-on-demand continuously retransmit videos that are watched simultaneously by many viewers. Nearly all broadcasting protocols assume that the client set-top box has enough storage to store between 48 and 60 minutes of video. We propose to use this storage to anticipate the customer requests and to preload, say, the first 3 minutes of the top 16 to 20 videos. This would provide instantaneous access to these videos and also eliminate the extra bandwidth required to handle compressed video signal.We present two broadcasting protocols using partial preloading to eliminate this extra bandwidth. The first of these protocols, Polyharmonic Broadcasting with Partial Preloading (PHB-PP), partitions each video into between 20 and 160 segments of equal duration and allocates a separate data stream to each individual segment. Our second protocol, the Mayan Temple Broadcasting protocol, uses fewer data streams but requires more overall bandwidth.