Impulsive Noise Impact on ADSL2+ Systems

This paper aims to characterize how the impulse noise impacts on services and applications for a broadband system using an ADSL2+ (Asymmetric Digital Subscriber Line, extended bandwidth) loop. The first approach employs the impulse noise defined in the G.996.1 (Test Procedures for DSL Transceivers) and TR-048 (ADSL Interoperability Test Plan) recommendations from ITU-T and DSL Forum, respectively. The second approach assesses system performance under REIN (Repetitive Electrical Impulse Noise) disturbance, which often occurs in the PSTN (Public Switched Telephone Network). REIN does not disturb the telephone service, however being quite harmful to ADSL. Metrics at packet level, as packet rate, lost packet count, bandwidth, short-term average transfer delay, and errored seconds, are used in order to characterize the DSL loop subjected to the referred noise impairments. After that, perceptual metrics are used along with QoS (Quality of Service) objective metrics to identify the impulse noise impact to the final user, leading to a QoE (Quality of Experience) analysis of the system.