Abstract: In a broadband wireless communication system, a spread spectrum signal is intentionally overlapped with an OFDM signal, in a time domain, a frequency domain, or both. The OFDM signal, which inherently has a high spectral efficiency, is used for carrying broadband data or control information. The spread spectrum signal, which is designed to have a high spread gain for overcoming severe interference, is used for facilitating system functions such as initial random access, channel probing, or short messaging. Methods and techniques are devised to ensure that the mutual interference between the overlapped signals is minimized to have insignificant impact on either signal and that both signals are detectable with expected performance by a receiver.

Abstract: A method and system are disclosed for enabling full-service communications between a full-service cable modem termination system (fsCMTS) and a plurality of full-service cable modems (fsCMs) for a conventional two way hybrid fiber-coax (HFC) cable television network. Full-service communications include data, voice and video. Video includes broadcast quality MPEG-2 transport packet streams and Internet protocol media streams. A multi-channel full-service media-access-control (fsMAC) coordinates the access to the shared upstream and downstream channels. Several MAC management messages are defined to enable a multi-channel full-service MAC domain to facilitate sharing of an arbitrary number of channels and to enable packet-by-packet true seamless channel change. Multiple upstream channels can be used in various ways to best optimize the use of the spectrum for meeting the quality-of-services needed by different services.

Abstract: A technique includes basing a discrete frequency transformation on the number of subcarriers in a predetermined set of subcarriers. One or more subcarriers of the set are assigned to modulate data, and the remaining subcarriers of the set are not assigned to modulate the data. The discrete frequency transformation is performed on the data to modulate the data, and mathematical operations that are associated with the subcarriers not assigned to modulate the data are excluded from the transformation.

Abstract: A network relaying apparatus and method for routing and transferring packets at high speed. A transfer engine stores the packets received through a network interface in a packet buffer, and stores the header information in a header RAM. A search engine searches the transfer control information including the transfer destination information and the action information in accordance with the header information, and writes it in the header RAM. The transfer engine produces an output packet based on the information stored in the packet buffer and the header RAM and outputs it to the transfer destination. A switch switches the output packet to the routing process of the destination. The transfer engine executes the receiving process and the transmission process, and the search engine executes the input search process and the output search process. Each of these processes is executed by pipelining control using a required table independently.