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UBC Theses and Dissertations

Quality of service support for wireless data systems over HFC cable TV networks Elfeitori, Anwar, A


We propose a cost effective deployment of Third Generation (3G) Wireless systems, and Wireless LANs (WLANs) over Hybrid Fiber Coaxial (HFC) CATV networks. WLANs and 3G networks are viewed as two wireless data technologies that complement each other in different environments. The main goal is to facilitates 3G/WLAN integration over the existing CATV plant, and reduce the huge cost for building a dedicated last mile infrastructure for 3G and WLAN access networks. For example, the last mile infrastructure cost for 3G systems accounts for more than 20% of a 3G system total cost. This is a major cost considering the tens of billions of dollars to be invested in 3G networks world-wide. Our proposal reduces the last mile cost by sharing the existing CATV network, and using the standard equipment and protocols of Data-Over-Cable Systems Interface Specifications (DOCSIS). This allows rapid deployment of wireless data systems, facilitates convergence of wireless and wireline networks, and paves the way towards all IP wireless networks. Special features and enhancements to DOCSIS Medium Access Control (MAC) protocol must be implemented in order to support Quality of Service (QoS) guarantees for Wireless users' data and signalling traffic. First, we conduct a traffic study for estimating the wireless data traffic loads in different geographical areas. We use the results of this study to ensure that CATV networks have adequate capacity for supporting wireless data users in addition to the existing services like CATV broadcasting and high-speed Internet access. The traffic study results are also used for mapping wireless network elements to an HFC CATV network. Second, we define a network architecture for deploying 3G systems over HFC networks. We identify the required components and functionalities for 3G over HFC deployment. Rather than defining a generic 3G/HFC architecture, we choose to define a specific 3G/HFC deployment. We select deploying 3G Universal Mobile Telecommunications System (UMTS) over DOCSIS CATV networks. Also, we define the required protocol stack for our UMTS over HFC deployment. Despite our specific UMTS over HFC deployment, our proposal can be extended to integrate other wireless data networks. Third, we propose a network architecture for interworking WLANs and UMTS networks over , DOCSIS CATV networks. The proposed architecture is independent of the WLAN/ 3G coupling chosen (e.g., loose coupling, or tight coupling). Different WLAN/ 3G interworking scenarios can be accommodated. We identify the network elements needed, and define the protocol stack for our deployment. Fourth, we present a QoS framework for DOCSIS CATV networks. The proposed QoS framework identifies, and discusses the required QoS functions in DOCSIS Cable Modem Termination System (CMTS), and Cable Modems (CMs). These functions are proposed for deployment in the upstream, and the downstream of DOCSIS transmission plane. Fifth, we present an implementation of DOCSIS MAC protocol that facilitates the proposed 3G/HFC deployment. Also, we enhance the DOCSIS MAC protocol with features that enable it to support QoS guarantees for multiple traffic classes. We focus on real-time traffic that requires very strict delay guarantees. The proposed MAC enhancements can be used for supporting real-time wireless traffic as well as other real-time wireline Internet traffic. Performance analysis for the proposed MAC protocol shows that QoS guarantees for real-time traffic is assured. Sixth, we propose a Weighted Fair Queueing (WFQ) based MAC Scheduler for DOCSIS networks. We identify scheduling at the MAC layer as crucial for QoS guaranties for both wireline and wireless traffic. Our WFQ scheduler guarantees QoS for both wireline and wireless traffic. Real-time traffic is provided with QoS guarantees without sacrificing QoS for other traffic classes with less stringent QoS requirements.

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