A Software Defined Radio Based DOCSIS 3.1 Measurement Receiver

The Data Over Cable Service Interface Specification (DOCSIS) provides internet access via cable TV networks. The latest version 3.1 replaces the Physical Layer of previous DOCSIS versions. With DOCSIS 3.1, broadband cable network operators want to accelerate their networks to gigabit-per-second speeds. Enhancements include an increased bandwidth per downstream channel of up to 192MHz, Orthogonal Frequency-Division Multiplex with a 4096 Quadrature Amplitude Modulation, and Low Density Parity Check Codes. These changes require new high performance hard-and software decoders. This paper presents the concept of a measurement receiver based on Software Defined Radio (SDR). The measurement receiver features a novel hardware frontend, an improved pre-FFT timing and frequency offset estimation under Roll-Off conditions, a high-performance LDPC decoder, and a Graphical User Interface for data analysis. It is shown that the SDR approach achieves good performance and is suitable for a DOCSIS 3.1 measurement decoder that focuses primarily on the Physical Link Channel.