Heterogeneous Wireless Access Networks Research Articles

Seamless Streaming Media for Heterogeneous Mobile Networks

As the mobile networking technologies evolve, people are able to access the Internet through heterogeneous wireless access networks, such as WLAN, GPRS, 3G and Beyond 3G networks. For the coverage,...

IPv6-based dynamic coordinated call admission control mechanism over integrated wireless networks

Many wireless access systems have been developed recently to support users mobility and ubiquitous communication. Nevertheless, these systems always work independently and cannot simultaneously serve users properly. In this paper, we aim to integrate IPv6-based wireless access systems and propose a coordinated call admission control mechanism to utilize the total bandwidth of these systems to minimize the call blocking probabilities, especially the handoff call dropping probabilities. First, we propose an integrated hierarchical wireless architecture over IPv6-based networks to combine the wireless access systems including cellular systems (second-generation, General Packet Radio Service, or third-generation), IEEE 802.11 a/b/g WLAN, and Bluetooth. In the proposed architecture, mobile user can request a call with quality-of-service (QoS) requirements by any wireless network interfaces that can be accessed. When the proposed coordinated call admission control (CCAC) mechanism receives a request, it takes the QoS requirements of the incoming call and the available and reserved bandwidth of this wireless system into consideration to accept or reject this request. Besides, the mechanism can coordinate with other wireless systems dynamically to adjust the bandwidth reserved for handoff calls at each wireless system in this architecture so as to reduce the call blocking probabilities. Once the call is admitted, the mobile user is able to access heterogeneous wireless access networks via multiple interfaces simultaneously. Finally, we evaluate this system to show that the CCAC on the proposed architecture outperforms other mechanisms proposed before.

Efficient resource allocation for China's 3G/4G wireless networks

The all-IP DiffServ model is expected to be the most promising architecture for QoS provisioning in China's next-generation wireless networks, due to its scalability, convenience for mobility support, and capability of interworking heterogeneous radio access networks. This article focuses on efficient resource allocation in a wireless DiffServ architecture. Resource utilization efficiency is particularly important for China's wireless networks as the mobile user density in China is and will continue to be much higher than that in other countries. More specifically, we propose a novel buffer sharing scheme to provide assured service for real-time layer-coded multimedia traffic, which can guarantee the specific packet loss requirement of each layer with UDP as the transport layer protocol. An adaptive optimal buffer configuration can be applied to achieve maximum resource utilization over the time-varying channel. Assured service is also provided to TCP data traffic for guaranteed throughput, where the cross-layer coupling between the TCP layer and link layer is exploited to efficiently utilize the wireless resources.

Analysis of handoff in a location-aware vertical multi-access network

Integration of WLAN hotspots into next generation cellular networks requires considerations on location management, resource allocation, handoff algorithms and their sensitivity to mobility related features such as velocity of the mobile and the handoff delay. This article presents architecture for seamless location-aware integration of WLAN hotspots into cellular networks and provides an analysis for an optimal handoff decision in moving in and out of a hotspot. For a mobile station, it may be beneficial to know the whereabouts of the hotspots in order to facilitate optimal handoff between the two access networks. In an integrated cellular-WLAN environment, one has to consider location management as part of mobility management due to differences in the cell sizes of the two overlapping technologies. Location information acquired through GPS may be helpful in some cases for advanced location management. In this paper we propose a location-aware architecture to support vertical roaming among heterogeneous wireless access networks. The article includes a description of a preliminary system architecture and the procedures and algorithms needed to implement mobility and location management. In conclusion, a comparison is given of two handoff algorithms (power and dwell-timer based) for moving-in and moving-out transitions, and their sensitivity to mobile velocity and handoff delay.

Quality-of-service signaling for next-generation IP-based mobile networks

We present a novel end-to-end QoS architecture that enables seamless services over heterogeneous wireless access networks. We discuss the main architectural approaches and design issues of mobility-aware QoS signaling in IP networks. Then we introduce a QoS signaling architecture that integrates resource management with mobility management. It is based on a domain resource manager concept and nicely supports various handover types in an integrated approach. In particular, we support anticipated handover with pre-reservation of resources over the old network before the mobile node is attached to the new access point.

Multicasting streaming media to mobile users

Content distribution in general, and multicasting in particular, over a wired network to static hosts can be realized by placing proxies and gateways at several parts of the network. However, if the end hosts are mobile over heterogeneous wireless access networks, one needs to consider many operational issues such as network detection, handoff, join and leave latency, and desired level of quality of service, as well as caching and load balancing. This article surveys a set of protocols and technologies that offer multicast-based services for streaming multimedia in a mobile environment. It also brings forth some of the issues related to mobile content distribution in the wireless Internet that may be helpful during its deployment by application service providers.

Design, implementation, and evaluation of programmable handoff in mobile networks

We describe the design, implementation and evaluation of a programmable architecture for profiling, composing and deploying handoff services. We argue that future wireless access networks should be built on a foundation of open programmable networking allowing for the dynamic deployment of new mobile and wireless services. Customizing handoff control and mobility management in this manner calls for advances in software and networking technologies in order to respond to specific radio, mobility and service quality requirements of future wireless Internet service providers. Two new handoff services are deployed using programmable mobile networking techniques. First, we describe a “multi-handoff” access network service, which is capable of simultaneously supporting multiple styles of handoff control over the same physical wireless infrastructure. Second, we discuss a “reflective handoff” service, which allows programmable mobile devices to freely roam between heterogeneous wireless access networks that support different signaling systems. Evaluation results indicate that programmable handoff architectures are capable of scaling to support a large number of mobile devices while achieving similar performance to that of native signaling systems.