摘要:
A scalable server architecture for use in implementing scaled media servers capable of simultaneous real-time data stream retrieval for large numbers of subscribers. A scalable server includes a plurality of stream pumping engines each accessing a particular storage device of a storage subsystem, and a server processor which receives retrieval requests from subscribers and directs the stream pumping engines to retrieve the requested data streams. Each of the stream pumping engines may include a storage controller coupled to its corresponding storage device for directing retrieval of the requested stream therefrom, a network controller for supplying the retrieved stream to a client network, and a processor for directing the operation of the storage and network controllers. Each of the stream pumping engines may also include a shared memory accessible by the corresponding stream pumping engine processor and the server processor. The shared memory facilitates communication with other stream pumping engines via the server processor and server system bus. A scaled media server may be implemented by cross-connecting several scalable servers with a plurality of stream multiplexers. Each of the stream multiplexers can include a separate packet input unit for processing the packets of each media stream such that two distinct levels of transmission priority are provided and quality of server restrictions are satisfied for all streams.
摘要:
A method and apparatus for storage and retrieval of multiple data streams in a multimedia distribution system. A given data stream is separated into a plurality of portions, and the portions are stored in a multi-disk storage system with Y disks each having X zones such that the ith portion of the given stream is stored in zone (i mod X) of disk (i mod Y). The number X of zones per disk and the number Y of disks are selected as relatively prime numbers. The stored data are retrieved using Y independent retrieval schedulers which are circulated among the Y disks over a number of scheduling intervals. Each retrieval scheduler processes multiple requests separated into X groups, with the requests of each group accessing the same disk zone during a given scheduling interval. The retrieval schedulers are also configured such that the retrieval requests of a given retrieval scheduler access the same disk during a given scheduling interval. The data stream placement technique in conjunction with the retrieval schedulers provide sequential-like parallel retrieval suitable for supporting real-time multimedia data distribution for large numbers of clients.
摘要翻译:一种用于在多媒体分发系统中存储和检索多个数据流的方法和装置。 给定的数据流被分成多个部分,并且这些部分被存储在多盘存储系统中,每个Y盘具有X个区域,使得给定流的第i个部分被存储在 磁盘(i mod Y)。 选择每个磁盘区域的数量X和磁盘的数量Y作为相对素数。 使用Y个独立的检索调度器检索存储的数据,这些调度器在多个调度间隔中在Y个盘之间循环。 每个检索调度程序处理分离成X组的多个请求,每个组的请求在给定的调度间隔期间访问相同的磁盘区。 检索调度器还被配置为使得给定检索调度程序的检索请求在给定调度间隔期间访问相同的盘。 数据流放置技术与检索调度器一起提供了适合于支持大量客户端的实时多媒体数据分发的顺序式并行检索。
摘要:
A cable network is provided with at least one bridge that is connected to a first cable segment of the cable network. The bridge receives from a shared communication medium a first carrier signal, having a first carrier frequency that is allocated for intra cable segment packet communication, containing packets modulated thereon. The bridge demodulates selected packets originating in the first cable segment from the first carrier signal. The bridge modulates each of the demodulated packets, that are destined outside of the first cable segment, onto a second carrier signal having a second carrier frequency. The bridge then transmits the second carrier signal on an upstream link of the common shared medium.
摘要:
A method and system are disclosed for scheduling the assignment and writing of cells from cell sources into a outgoing bitstream transmitted from each device of an ATM communications network. The timeslots are organized into fixed length cycles which cycles each have a sequence of N timeslots, where N is an integer >1. Furthermore, each cycle is divided into at least one round comprising a variable length subsequence of the timeslots of the cycle. During each timeslot of a uniform timeslot clock, at least one subset of the sources is identified. Each subset corresponds to a round. One cell from each subset is assigned to, and written into, a respective timeslot of the corresponding round. During each timeslot of the timeslot clock, each of the sources is assigned a priority state depending on how many cells of that source have been previously assigned to timeslots during the current cycle and whether or not that source has a cell available for assignment to a round during that timeslot. The highest priority state assigned to any source during each timeslot is identified. One of the cells of each source with the identified highest priority state are assigned to, and written into, a timeslot of a corresponding round, in a round-robin fashion, to form the subsequence of cells of that round.
摘要:
A scalable server architecture for use in implementing scaled media servers capable of simultaneous real-time data stream retrieval for large numbers of subscribers. A scalable server includes a plurality of stream pumping engines each accessing a particular storage device of a storage subsystem, and a server processor which receives retrieval requests from subscribers and directs the stream pumping engines to retrieve the requested data streams. Each of the stream pumping engines may include a storage controller coupled to its corresponding storage device for directing retrieval of the requested stream therefrom, a network controller for supplying the retrieved stream to a client network, and a processor for directing the operation of the storage and network controllers. Each of the stream pumping engines may also include a shared memory accessible by the corresponding stream pumping engine processor and the server processor. The shared memory facilitates communication with other stream pumping engines via the server processor and server system bus. A scaled media server may be implemented by cross-connecting several scalable servers with a plurality of stream multiplexers. Each of the stream multiplexers can include a separate packet input unit for processing the packets of each media stream such that two distinct levels of transmission priority are provided and quality of server restrictions are satisfied for all streams.
摘要:
A transport protocol that meets the requirements and performance for multimedia data transfer in a wireless link includes a transmitting/sending station and a receiving station. The inventive protocol is referred to as the Burst-oriented Transport with Time-bounded Retransmission (BTTR). This scheme uses a large transmission window for sending/receiving a burst of time-sensitive data and, within this window, several smaller observation windows are used for dynamic error retransmission. There is a time limitation on each retransmission such that the burst of data can be received in a timely manner, and thus trading some packet losses (still in an acceptable range) for delay and throughput performance. Specifically, the wireless network includes a wireless station for transmitting data over a wireless link. The sending station transmits a plurality of sequential data packets to the receiving station, wherein each plurality of sequential data packets form a respective Group-of-Packet (GOP). The receiving station detects whether any of the received data packets in each current GOP are corrupted before receipt of all data packets in the current GOP. The receiving station then transmits a negative acknowledgement (ACK) packet to the sending station before the receipt of all data packets in the current GOP, if at least one data packet in the current GOP is corrupted. Note that the ACK packet indicates which data packets are corrupted. In addition, the sending station selectively retransmits the data packets based on the indication of the received ACK packet before transmitting the next GOP to the receiving station.
摘要:
A communication system comprising a channel encoder to generate a binary bit stream, a mapping unit coupled to the channel encoder, the mapping unit configured to receive the binary bit stream from the channel encoder and to map every “n” consecutive bits of the binary bit stream into a symbol in accordance with a mapping table, wherein the symbol has a symbol value related to a modulation mode, “n” being a positive integer, and a number of “m” modulation units coupled to the mapping unit, “m” being a positive integer, the modulation units configured to receive a set of “m” symbols from the mapping unit and modulate the set of “m” symbols based on the modulation mode, wherein a combined value of the symbol values of the set of “m” symbols from the mapping unit is distinguishable from another combined value of the symbol values of another set of “m” symbols from the mapping unit, and wherein a combined value of the symbol values of a set of “m” symbols from the mapping unit corresponds to a distinguishable bit value of the “n” consecutive bits in the binary bit stream.
摘要:
A digital signal processor structure by performing length-scalable Fast Fourier Transformation (FFT) discloses a single processor element (single PE), and a simple and effective address generator are used to achieve length-scalable, high performance, and low power consumption in split-radix-2/4 FFT or IFFT module. In order to meet different communication standards, the digital signal processor structure has run-time configuration to perform for different length requirements. Moreover, its execution time can fit the standards of Fast Fourier Transformation (FFT) or Inverse Fast Fourier Transformation (IFFT).
摘要:
An ultra-wideband (UWB) transceiver for use in UWB communication includes a voltage-controlled oscillator (VCO) configured to periodically and sequentially generate a series of base frequencies based on a predetermined sequence and a waveform generator to generate carrier waves based on the generated base frequencies.
摘要:
A system and method are provided for assigning routing tag bits for routing signals through a Benes network comprising an input stage and an output stage. The input and output stages each comprise a column of 2.times.2 .beta. elements which route an inputted signal to an upper output if the control sequence bit is 0 and to a lower output if the control sequence bit is 1. Each signal inputted to the Benes network is associated with control sequence. For a particular Benes, in a particular control stage of the Benes network, a 0 is assigned to a control sequence bit associated with a signal q.sub.0 received at an upper input of a topmost input stage .beta. element. A 1 is assigned to a control sequence bit associated with a signal q.sub.k received at the same output stage p element as the signal q.sub.0. A 1 is assigned to a control sequence bit associated with a signal q.sub.1 received at a lower input of the topmost input stage .beta. element. A 0 to is assigned to a control sequence bit associated with a signal q.sub.k ' received at the same output stage .beta. element as the signal q.sub.1. For at least one signal q.sub.p for which no control sequence bit is yet assigned, either a 0 or a 1 is assigned to the control sequence bit associated with the signal q.sub.p. The complement of the chosen control sequence bit is assigned to a control sequence bit associated with a signal q.sub.k " received at the same output stage .beta. element as the signal q.sub.p.
摘要翻译:提供了一种系统和方法,用于通过包括输入级和输出级的Benes网络为路由信号分配路由标签位。 如果控制序列位为0,则输入和输出级各自包括2×2β元件的列,其将输入的信号路由到上输出,并且如果控制序列位为1,则将其输入到较低的输出。输入到Benes网络的每个信号是 与控制序列相关。 对于特定的Benes,在Benes网络的特定控制级中,将0分配给与在最上面的输入级β元件的上部输入处接收的信号q0相关联的控制序列位。 A 1被分配给与在与信号q0相同的输出级p元件处接收的信号qk相关联的控制序列位。 A 1被分配给与在最上面的输入级β元件的较低输入处接收的信号q1相关联的控制序列位。 A 0被分配给与在与信号q1相同的输出级β元件处接收的信号qk'相关联的控制序列位。 对于尚未分配控制序列位的至少一个信号qp,将0或1分配给与信号qp相关联的控制序列位。 所选择的控制序列位的补码被分配给与在与信号qp相同的输出级β元件处接收的信号qk“相关联的控制序列位。