Patent ID: 7876697
Filing Date: 2011-01-25
Classification: H04B,H04L

Abstract:
1. An apparatus for characterizing modulation schemes for a network comprising: a controller configured to instruct a network element to transmit a test signal at a test frequency, a first modulation scheme and a first power level; a receiver configured to receive the test signal from the network element; and a multiple tap equalizer which measures a signal to noise ratio of the test signal based on measurement of at least one of a packet error rate, a modulation error ratio, or a bit error rate of the test signal, wherein the controller determines if the signal to noise ratio is within a predetermined range of an estimated signal to noise ratio, and the controller determines that the modulation scheme has excessive inband interference or phase noise when the signal to noise ratio is not within a predetermined range of an estimated signal to noise ratio, wherein the controller is further configured to instruct the network element to transmit a second test signal at a second modulation scheme different from the first modulation scheme, and to determine if a second signal to noise ratio associated with the second test signal is within a predetermined range of a second estimated signal to noise ratio, and the controller determines that the second modulation scheme has excessive inband interference or phase noise when the second signal to noise ratio is not within a predetermined range of the second estimated signal to noise ratio, wherein the controller is further configured to determine which modulation schemes provide a signal to noise ratio is within a predetermined range of an estimated signal to noise ratio.