This paper provides a new approach to mitigate the crosstalk interference in the symmetric digital subscriber line (SDSL) upstream transmission. A vector channel equalizer has been proposed for the SDSL upstream receiver to enhance spectral compatibility for the SDSL services. This approach outperforms a conventional scalar equalizer, which used in the current SDSL systems, is about a 15 dB gain in mean squared error (MSE). It significantly suppresses the crosstalk degradation and ensures the quality of service (QoS) on the SDSL transmission throughput. Moreover, the enhancement of the SDSL receiver can benefit on the extension of the SDSL deployment coverage range and also guarantees its promising data rates on increasing numbers of customer subscribers.

We studied the impact of the channel noise, especially additive white Gaussian noise (AWGN) over the broadband HFC access network. The modulation scheme of this digital communication channel is QPSK. We have derived a network system error model for the HFC communication channel, which yields a relationship between bit error rate and signal to noise ratio (SNR) in a noisy communication channel. We measured in the laboratory packet loss as a function of SNR for this HFC communication network, and derived an empirical relationship between the physical layer bit error rate (BER) and the higher layer packet loss. The results of this study would be beneficial in network management of broadband HFC access network.