Matching Items (142)
Description
The integration of passive optical networks (PONs) and wireless mesh networks (WMNs) into Fiber-Wireless (FiWi) networks has recently emerged as a promising strategy for
providing flexible network services at relative high transmission rates. This work investigates the effectiveness of localized routing that prioritizes transmissions over the local gateway to the optical network and avoids wireless packet transmissions in radio zones that do not contain the packet source or destination. Existing routing schemes for FiWi networks consider mainly hop-count and delay metrics over a flat WMN node topology and do not specifically prioritize the local network structure. The combination of clustered and localized routing (CluLoR) performs better in terms of throughput-delay compared to routing schemes that are based on minimum hop-count which do not consider traffic localization. Subsequently, this work also investigates the packet delays when relatively low-rate traffic that has traversed a wireless network is mixed with conventional high-rate PON-only traffic. A range of different FiWi network architectures with different dynamic bandwidth allocation (DBA) mechanisms is considered. The grouping of the optical network units (ONUs) in the double-phase polling (DPP) DBA mechanism in long-range (order of 100~Km) FiWi networks is closely examined, and a novel grouping by cycle length (GCL) strategy that achieves favorable packet delay performance is introduced. At the end, this work proposes a novel backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations (e.g., LTE eNBs) and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateway (S/P-GW). The Sm-GW accommodates flexible number of small cells while reducing the infrastructure requirements at the S-GW of LTE backhaul. In contrast to existing methods, the proposed Sm-GW incorporates the scheduling mechanisms to achieve the network fairness while sharing the resources among all the connected small cells base stations.
providing flexible network services at relative high transmission rates. This work investigates the effectiveness of localized routing that prioritizes transmissions over the local gateway to the optical network and avoids wireless packet transmissions in radio zones that do not contain the packet source or destination. Existing routing schemes for FiWi networks consider mainly hop-count and delay metrics over a flat WMN node topology and do not specifically prioritize the local network structure. The combination of clustered and localized routing (CluLoR) performs better in terms of throughput-delay compared to routing schemes that are based on minimum hop-count which do not consider traffic localization. Subsequently, this work also investigates the packet delays when relatively low-rate traffic that has traversed a wireless network is mixed with conventional high-rate PON-only traffic. A range of different FiWi network architectures with different dynamic bandwidth allocation (DBA) mechanisms is considered. The grouping of the optical network units (ONUs) in the double-phase polling (DPP) DBA mechanism in long-range (order of 100~Km) FiWi networks is closely examined, and a novel grouping by cycle length (GCL) strategy that achieves favorable packet delay performance is introduced. At the end, this work proposes a novel backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations (e.g., LTE eNBs) and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateway (S/P-GW). The Sm-GW accommodates flexible number of small cells while reducing the infrastructure requirements at the S-GW of LTE backhaul. In contrast to existing methods, the proposed Sm-GW incorporates the scheduling mechanisms to achieve the network fairness while sharing the resources among all the connected small cells base stations.
ContributorsDashti, Yousef (Author) / Reisslein, Martin (Thesis advisor) / Zhang, Yanchao (Committee member) / Fowler, John (Committee member) / Seeling, Patrick (Committee member) / Arizona State University (Publisher)
Created2016
Description
There has been a lot of work on the characterization of capacity and achievable rate regions, and rate region outer-bounds for various multi-user channels of interest. Parallel to the developed information theoretic results, practical codes have also been designed for some multi-user channels such as multiple access channels, broadcast channels and relay channels; however, interference channels have not received much attention and only a limited amount of work has been conducted on them. With this motivation, in this dissertation, design of practical and implementable channel codes is studied focusing on multi-user channels with special emphasis on interference channels; in particular, irregular low-density-parity-check codes are exploited for a variety of cases and trellis based codes for short block length designs are performed.
Novel code design approaches are first studied for the two-user Gaussian multiple access channel. Exploiting Gaussian mixture approximation, new methods are proposed wherein the optimized codes are shown to improve upon the available designs and off-the-shelf point-to-point codes applied to the multiple access channel scenario. The code design is then examined for the two-user Gaussian interference channel implementing the Han-Kobayashi encoding and decoding strategy. Compared with the point-to-point codes, the newly designed codes consistently offer better performance. Parallel to this work, code design is explored for the discrete memoryless interference channels wherein the channel inputs and outputs are taken from a finite alphabet and it is demonstrated that the designed codes are superior to the single user codes used with time sharing. Finally, the code design principles are also investigated for the two-user Gaussian interference channel employing trellis-based codes with short block lengths for the case of strong and mixed interference levels.
Novel code design approaches are first studied for the two-user Gaussian multiple access channel. Exploiting Gaussian mixture approximation, new methods are proposed wherein the optimized codes are shown to improve upon the available designs and off-the-shelf point-to-point codes applied to the multiple access channel scenario. The code design is then examined for the two-user Gaussian interference channel implementing the Han-Kobayashi encoding and decoding strategy. Compared with the point-to-point codes, the newly designed codes consistently offer better performance. Parallel to this work, code design is explored for the discrete memoryless interference channels wherein the channel inputs and outputs are taken from a finite alphabet and it is demonstrated that the designed codes are superior to the single user codes used with time sharing. Finally, the code design principles are also investigated for the two-user Gaussian interference channel employing trellis-based codes with short block lengths for the case of strong and mixed interference levels.
ContributorsSharifi, Shahrouz (Author) / Duman, Tolga M. (Thesis advisor) / Zhang, Junshan (Committee member) / Tepedelenlioğlu, Cihan (Committee member) / Reisslein, Martin (Committee member) / Arizona State University (Publisher)
Created2015