Mobile Hotspots Research Articles

Authenticated route optimization scheme for network mobility (NEMO) support in heterogeneous networks

AbstractFor the efficient communications between mobile or fixed hosts in mobile networks, the route optimization and its security are indispensable. So, the Internet Engineering Task Force introduced a NEMO basic support protocol in 2005. However, this protocol does not provide a strong security between hosts and especially in nested‐mobile network it can incur a pinball routing problem. And the previous Proxy Binding Update (PUB) protocol has an advantage that can prove the ownership of address of a host using Multi‐key Cryptographically Generated Address (MCGA) which can alleviate a neighbor bombing attack. However, a Mobile Network Node (MNN) belonging to the mobile network which can have low power or limited computing capability may be require burdened costs such as signification and verification of messages. Also, the PUB protocol does not provide the secure message communication architecture between the MNN and its Mobile Router (MR). In this paper we propose a CGA‐based Authentication Route Optimization scheme (CARO) in mobile hotspots with heterogeneous networks. The proposed CARO protocol satisfies two problems using IPsec Encapsulating Security Payload (ESP) tunnel, a secret mobile group key, and the CGA. And we also do not require the considerable computing costs to the MNN or a Correspondent Node. In performance analysis, we prove more secure and efficient protocols than the previous protocols using the defense of various attacks and the result of computational cost, etc. Copyright © 2010 John Wiley & Sons, Ltd.

Proxy-Based Wireless Data Access Algorithms in Mobile Hotspots

In this paper, we investigate efficient wireless data access algorithms in mobile hotspots. We introduce a proxy cache (PC) and propose PC-based poll-each-read (P-PER) and PC-based callback (P-CB) data access algorithms to reduce the transmission cost over wireless links in mobile hotspots. An analytical model is developed, and extensive simulations are conducted to demonstrate the performance of P-PER and P-CB. It is shown that P-PER and P-CB can improve cache hit performance and significantly reduce transmission cost. A tradeoff between P-PER and P-CB suggests the need to use a hybrid proxy-based approach to attain optimal performance of wireless data access in mobile hotspots.

Throughput Analysis of TCP-Friendly Rate Control in Mobile Hotspots

By integrating wireless wide area networks (WWANs) and wireless local area networks (WLANs), mobile hotspot technologies enable seamless Internet multimedia services to users on-board a vehicle. In this paper, we investigate the performance of TCP-Friendly Rate Control (TFRC) protocol supporting multimedia services in mobile hotspots. To quantify the throughput of TFRC flows in mobile hotspots, we first develop discrete-time queuing models for the WWAN link and the WLAN link. We then derive the steady state TFRC throughput using an iterative algorithm. Analytical and extensive simulation results reveal how the end-to-end TFRC throughput is affected by the number of users in a mobile hotspot, the vehicle velocity, the WWAN/WLAN link bandwidth, the retransmission limit, and the buffer size. It is found that the WWAN channel profile and link bandwidth have significant impacts on the TFRC throughput, and therefore suitable resource allocation and admission control are indispensable for the quality and efficiency of multimedia services in mobile hotspots.

Performance Analysis of Mobile Hotspots with Heterogeneous Wireless Links

Mobile hotspot enabling Internet access services in moving vehicles is an important service for ubiquitous computing. In this paper, we propose an analytical framework for studying the packet loss behavior and throughput in a mobile hotspot with heterogeneous wireless links. We first develop a two-state Markov model for the integrated wireless wide area network (WWAN) and wireless local area network (WLAN). We then derive the expressions that describe the experienced packet loss probability, packet loss burst length, and throughput. Finally, we present simulation results to verify the accuracy of our analysis. It is concluded that adaptive and cross-layer approaches should be deployed to improve the performance of mobile hotspots.

Mobility Management in Mobile Hotspots with Heterogeneous Multihop Wireless Links

In this article we study two representative mobility management schemes for mobile hotspots with heterogeneous multihop wireless links: the NEMO basic support protocol at the network layer and the SIP-based network mobility support protocol at the application layer. We evaluate their salient features and quantify their handoff latency. It is shown that the SIP-based network mobility support protocol can easily be deployed and reduce the tunneling overhead incurred in the NEMO basic support protocol. However, it increases handoff latency due to longer message length. We also discuss several open research issues for seamless mobility support in mobile hotspots.

Integration of IEEE 802.11 WLANs with IEEE 802.16-based multihop infrastructure mesh/relay networks: A game-theoretic approach to radio resource management

One of the promising applications of IEEE 802.16 (WiMAX)-based wireless mesh/relay networks is to provide infrastructure/backhaul support for IEEE 802.11-based mobile hotspots. In this article we present an architecture for integrating IEEE 802.11 WLANs with IEEE 802.16-based multihop wireless mesh infrastructure to relay WLAN traffic to the Internet. The major research issues in this integrated architecture are outlined and related work is reviewed. A game-theoretic model is developed for radio resource management in this integrated network architecture. In particular, a multiplayer bargaining game formulation is used for fair bandwidth allocation and optimal admission control of different types of connections (e.g., WLAN connections, relay connections, and connections from standalone subscriber stations) in an IEEE 802.16 base station/mesh router. Both connection-level and inconnection-level performances for this bandwidth management and admission control framework are presented

WIRELESS BROADBAND ACCESS: WIMAX AND BEYOND - Integration of WiMAX and WiFi: Optimal Pricing for Bandwidth Sharing

Broadband wireless access networks based on WiMAX can provide backhaul support for mobile WiFi hotspots. We consider an integrated WiMAX/WiFi network for such an application where the licensed WiMAX spectrum is shared by the WiFi access points/routers to provide Internet connectivity to mobile WiFi users. The WiMAX backbone network and WiFi hotspots are operated by different service providers. Issues such as protocol adaptation, quality of service support, and pricing for bandwidth sharing that are related to integration of these networks are discussed. In addition, we propose a model for optimal pricing for bandwidth sharing in an integrated WiMAX/WiFi network. A Stackelberg leader-follower game is formulated to obtain the optimal pricing solution for bandwidth sharing. Performance evaluation results reveal some interesting insights into the problem

End-to-end QoS provisioning in 4G with mobile hotspots

The novel concept of mobile hotspots, characterized by a group of wireless users equipped with wireless LAN cards, moving as a whole and requiring Internet connectivity, is gaining the interest of the telecommunications research community. This article intends to contribute to this research topic by proposing alternative solutions for the deployment of a mobile gateway device offering 3G connectivity to the group of WLAN users while they are moving. This is a decisive aspect of the 3G migration to 4G networks. The proposed solutions allow for two-hop wireless paths between WLAN and 3G systems, and performing control over-high layer issues, specifically focusing on end-to-end QoS provisioning. The pros and cons of envisaged design solutions are addressed and their relevance justified considering purposes, target users, and applications.

Securing VPNs: comparing SSL and IPsec

VPNs are essential today to connect roaming employees to their company network There are two very disparate choices of VPN to choose from; IPsec protocol VPN, and Secure Sockets Layer (SSL) VPN. These two products have vastly different approaches to doing the same thing. IT security managers must weigh up which of the two approaches fits most snugly in their network. Ray Stanton at BT details what both types of VPN can and can't do. IPsec VPNsSSL VPNsSits at Layer 3 of network stackSits at Layer 4,5 of network stackConnect hosts to entire private networksConnects users to applicationsClient software must be installed on the remote deviceOnly requires a standard Web browser - no client software necessaryNot really interoperableVery interoperableMore matureLegacy systems must be adapted Whatever the wireless standard being deployed and the latest smart phone that's currently in vogue, at the heart of most organizations' mobile and flexible working policy is a VPN. Replacing leased lines or dedicated dial-up connections, which were unsuitable for mobile working or expensive to run and re-configure, VPNs use the internet to connect employees back to their company's network. Unlike the private networks of the past, they are accessible around the world and, with the growth of mobile devices and wireless hotspots, users don't even require a socket to get online.

A Cross-Layer Approach for Concurrent Delay and Throughput Assurances in Multihop Wireless Hotspots

Next generation Wireless Local Area Networks (WLAN's) are likely to require multihop wireless connections between mobile nodes and Internet gateways to achieve high data rates from larger distances. The paper addresses the challenges in concurrently providing a wide range of end-to-end throughput and delay assurances in such mobile multihop WLAN hotspots. The proposed solution is based on the Neighborhood Proportional Delay Differentiation (NPDD) service model. With NPDD, Transmission Control Protocol (TCP) based applications achieve their desired throughputs using a dynamic class selection mechanism. This approach integrates well with the NPDD-based end-to-end delay assurance mechanism proposed earlier. To better model the node mobility in a multihop hotspot in our simulation studies, the Public Hotspot Mobility (PHM) model is proposed. Simulation results show that the proposed solution is better in meeting the desired throughputs and delays as compared with best effort and strict priority approaches. Recent theoretical analyses show that the NPDD model with a continuous range of classes can guarantee convergence to desirable QoS through dynamic class selection. However, the overhead of realizing the continuous class scheduler is high. We propose two continuous NPDD schedulers, the Single Queue Continuous NPDD (SQ-CNPDD) scheduler and the Multiple Queue Continuous NPDD (MQ-CNPDD) scheduler, to realize the continuous NPDD model. With simulations, the performance of SQ-CNPDD and MQ-CNPDD are compared to that of NPDD.

Information raining and optimal link-layer design for mobile hotspots

In this paper, we propose a link layer design for mobile hotspots. We design a novel system architecture that enables high-speed Internet access in railway systems. The proposed design uses a number of repeaters placed along the track and multiple antennas installed on the roof of a vehicle. Each packet is decomposed into smaller fragments and relayed to the vehicle via adjacent repeaters. We also use erasure coding to add parity fragments to original data. This approach is called information raining since fragments are rained upon the vehicle from adjacent repeaters. We investigate two instances of information raining. In blind information raining, all repeaters awaken when they sense the presence of the vehicle. The fragments are then blindly transmitted via awakened repeaters. A vehicle station installed inside the train is responsible for aggregating a large enough number of fragments. In the throughput-optimized information raining, the vehicle station selects a bipartite matching between repeaters and roof-top antennas and activates only a subset of the repeaters. It also dictates the amount of transmission power of each activated repeater. Both the bipartite matching and power allocations are individually shown to be NP-complete. Matching heuristics based on the Hungarian algorithm and Gale-Shapley algorithm are proposed. A simplex-type algorithm is proposed as the power allocation heuristics.