| In this thesis, a new approach on mitigating the cochannel interference (CCI), also called crosstalk, in the Asymmetric Digital Subscriber Line (ADSL) transmission system has been studied. This implementation ensures the spectral compatibility in the DMT-ADSL system together with other DSL services in a same binder cable.; The major part of this thesis concerns a modified technique for high-speed communication over the ADSL telephone network. Discrete Multitone (DMT)-ADSL, has been standardized in American National Standards Institute (ANSI) [1]. It offers bit rate up to 8 Mbps downstream and 1 Mbps upstream, depending on the deployment coverage ranges. A modified method based on multiuser detection is presented herein, which can mitigate the crosstalk interference in DMT-ADSL receiver.; An important issue for ADSL is the problem with crosstalk, which is a major threat in ADSL receiver with other DSL services in a same binder. The performance on the mitigation of ADSL channel crosstalk impairment is the most important criteria for guaranteeing the Quality of Service (QoS) in an ADSI, system. The essential issue of this thesis on optimizing the ADSL system transmission throughput is to modify its channel transceiver design. Treating an ADSI, channel as a multiple-input and single-output (MISO) system with desired ADSL signal and cochannel interference signals is just like a multiuser communication channel model. Our modified ADSL multiuser detection can greatly outperform the currently deployed single-user receiver with either increasing transmission data rates, or extending deployment rages in impairment environments. Joint Maximum Likelihood Sequence Estimation (JNILSE) gives very good performance in our proposed model, but known as a computationally complex technique. The last part of this thesis deals with low complexity multiuser detection to balance the ADSL system performance and computational complexity with a reasonable VLSI capability, which can be implemented in a sub-optimum solution.; With these approaches to the mitigation of ADSL impairments, the performance of the ADSL system is greatly enhanced; for example, the ADSL service can be either extended about 2-kft from the current limit, or has more than 30% transmission data rate improvement, depending on the cost requirements. Under these circumstances, the capacity of the network is utilized to a near sub-optimum solution.; [1]Asymmetric Digital Subscriber Line ( ADSL) Metallic Interface, ANSI Standard T.413-1995, ANSI, New York. |
