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A popular video can be broadcast by partitioning the video into segments, which are broadcast on several channels simultaneously and periodically. This method allows multiple users to share channels, leading to higher bandwidth utilization. Previous studies mainly focus on reducing viewers' waiting time. This work studies another important issue, namely client buffer (1) savings. A reverse fast broadcasting (RFB) scheme is proposed to alleviate the buffer problem. There are two specific properties for RFB. First, this scheme arranges the segments in descending order of their numeric indices on each channel at the server end. Second, RFB requires a client to receive segments as late as possible, such that the client buffers the smallest number of segments. RFB has the same waiting time as the fast broadcasting (FB) scheme, but just needs a half of buffer spaces required by FB. RFB also requires smaller client buffers than the pyramid broadcasting (PB), skyscraper broadcasting (SkB), greedy disk-conserving broadcasting (GDB), BroadCatch, and recursive frequency-splitting schemes. Moreover, if we apply the same changes to the PB, SkB and GDB schemes, their buffer requirements decrease by 25% to 75%. Index Terms--Buffers, cable TV, hot-video broadcasting, video-on-demand (VOD).

The design of optimal precoders which minimize the bit error rate (BER) for multiple-input /multiple-output (MIMO) downlink communication channels is investigated under the zero-forcing (ZF) condition. It is shown that the optimal full information control can be employed to design the optimal ZF precoder.