MULTI-POINT TO POINT COMMUNICATION SYSTEM

摘要

The communication system includes a hybrid fiber/coax distribution network. A head end provides for downstream transmission of telephony and control data in a first frequency bandwidth over the hybrid fiber/coax distribution network and reception of upstream telephony and control data in a second frequency bandwidth over the hybrid fiber/coax distribution network. The head end includes a head end multicarrier modem for modulating at least downstream telephony information on a plurality of orthogonal carriers in the first frequency bandwidth and demodulating at least upstream telephony information modulated on a plurality of orthogonal carriers in the second frequency bandwidth. The head end further includes a controller operatively connected to the head end multicarrier modem for controlling transmission of the downstream telephony information and downstream control data and for controlling receipt of the upstream control data and upstream telephony information. The system further includes service units, each service unit operatively connected to the hybrid fiber/coax dist ribution network for upstream transmission of telephony and control data in the second frequency bandwidth and for receipt of the downst ream control data and telephony in the first frequency b andwidth. Each service unit includes aservice unit multicarrier modem for modulating a t least the upstream telephony information at least one carrier orthogonal at the head end terminal to another carrier in the second frequency bandwidth and for demodulating at least downs tream telephony information modulated on at least a band of a plurality of orthogo nal carriers in the first frequency bandwidth. Each serv ice unit also includes a controller operatively connected to the service unit multica rrier modem for controlling the modulation of and demodu lation performed by the service unit multicarrier modem. A method of monitoring com munication channels, a distributed loop method for adjus ting transmission characteristics to allow for transmission of data in a multi-po int to point communication system, a polyphase filter te chnique for providing ingress protection and a scanning method for identifying frequ ency bands to be used for transmission by service units are also included.