Cable modem termination system for upstream frequency band
View Patent ↗The selection of which channel to use by a cable modem terminating system (CMTS) is made a function of input supplied by a spectrum analyzer. Note that typically the cable distribution system has coupled to it at the head end not only the CMTS but also a spectrum analyzer, which has been used in the prior art only for initial establishment and subsequent maintenance of the network, tasks which are performed manually by field technicians. In one embodiment of the invention an interface is established between the CMTS and the spectrum analyzer so that the CMTS and the spectrum analyzer can communicate with each other, and the decision on which channel to use for the upstream is made by the CMTS based at least in part on information provided by the spectrum analyzer. Alternatively, the CMTS and spectrum analyzer are each interfaced to a spectrum controller which makes the decision of which channel to use for the upstream based at least in part on information provided by the spectrum analyzer. The spectrum controller then instructs the CMTS to carry out its decision.
1. A method for use in connection with a cable modem system having a cable modem terminating system module and a spectrum analyzer each having a communication port, the method comprising the step of searching for a candidate channel having a specified bandwidth within the spectrum allocated for use as upstream channels that are indicated by said spectrum analyzer to have an acceptable noise level over a prescribed period of time wherein said searching step failed to find a channel with an acceptable noise level over said prescribed period, the method further comprising the steps of:
reducing said prescribed period of time; and
repeating said searching step.