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Based on the analysis of 802.11 link-layer handoff and representative cross-layer mechanisms supporting mobility, this paper proposes a Locator/Identifier Split Network Based Cross-Layer Roaming Mechanism (LISN-CLRM) with the Layer 2 and Layer 3 handoff coupling organically. Theoretical analysis shows that the total delay of this mechanism is much smaller than MIPv6, and is 77.5 ms smaller than SMOS[1]...
In this paper, we introduce a new priority and admission control mechanism for applications in the Vehicular Communication Networks (VCNs). The adopted network architecture integrates Vehicular Ad-hoc Networks (VANETs) based on the standard IEEE 802.11p and Wireless LAN Mesh Networks (WMNs) based on IEEE 802.11s. The proposed scheme is designed to ensure seamless provision of infrastructure-to-vehicle...
The IEEE 802.11 standard based Wireless Local Area Networks (WLANs) are widely deployed and have gained greater popularity. It is anticipated that WLAN will play an important rule in the future wireless communication systems in order to provide several gigabits data rate. However, it has been a challenging problem to support the IEEE 802.11 WLAN devices to fully exploit the high throughput gains offered...
Contemporary mobile devices such as smartphones and tablets are increasingly equipped with multiple network interfaces that enable automatic vertical handover between heterogeneous wireless networks including WiFi and cellular 3G and 4G networks. However, the employed vertical handover schemes are mostly quite simple, and incur non-negligible service disruptions to ongoing sessions, e.g., video streaming...
Efficient link management is important for mesh networking. The links opened between neighbor STAs should be stable and ensure high probability of packet delivery. Various approaches of link management are usually compared by simulation. The core contribution of this paper is original link management efficiency criteria and an analytical model of decision-making process of link management in IEEE...
As a conventional MAC control protocol for wireless networks, IEEE 802.11 DCF hasn't taken account into the requirement, which TCP/UDP hybrid stream access needs for MAC frame length. The TCP/UDP hybrid stream's transmission delay would increase significantly, that always generate failure of TCP stream transmitting. This paper proposes an improved IEEE 802.11 DCF protocol and theory model based on...
This paper develops a simple analytical model based on a Markov chain that calculates saturation throughput and average packet delay for the IEEE802.11 Distributed Coordination Function (DCF) for network scenarios with voice and data stations. The analytical model is validated by comparing its results with simulation outcome. Based on the analytical model, a methodology that calculates voice capacity...
This paper illustrates a semi-active handover algorithm on the integrated utilization of RSS and location, according to characteristics of a cellular network and WiFi. While connecting to a cellular network, MS (Mobile Station) is in the passive mode, where BS (Base Station) informs the MS to hand over on the basis of location information. In contrast, MS in the WiFi link chooses the optimal AP (Access...
Being reliable and real-time, are the two most challenging requirements of wireless industrial networks due to the shared, error-prone and non-deterministic behaviour of wireless communication medium. Retry-Limit (RL) parameter of IEEE 802.11 standard directly effects on the packet reliability, whereas other parameters mostly effect on packet delay. In this paper, at first the delay-reliability trade-off...
This paper investigates the impact of the hop-count and node density on the network performance of mobile ad-hoc networks (MANETs). The analysis as well as simulation results indicate that the throughput decreases significantly when the packets traverse over a long chain of hops. Especially when the link is beyond 4 hops, the throughput can only get less than 60% of the single hop throughput. In another...
The full coverage of continuous voice cloud services is still an open issue in an overlapping network, particularly with regard to heterogeneously public communication network infrastructures. However, hardly anyone of today's service providers offers seamless voice call continuity across these networks due to the high technical integration effort and economic cost. Given this backdrop, we present...
Vehicular Ad-hoc Network (VANET) is among the most relevant forms of mobile ad-hoc networks. VANET helps improving traffic safety and efficiency. By exchanging information between each others, vehicles can warn drivers or even prepare for dangerous situation. These warnings can be about critical situations like vehicles merging in a highway. Detecting and warning about such situations require a reliable...
In social swarming applications, participants equipped with 3G and WiFi-capable smart phones are tasked to provide reports (possibly voluminous ones that include full-motion video) about their immediate environment to a central coordinator. In this paper, we consider the problem of timely delivery of these reports: each report has an associated deadline and the goal of the system is to retrieve as...
With the development of wireless networks, the requirements on multimedia traffics, such as data, audio and video are more and more intensive. However, it is a difficult question to guarantee the Quality of Service (QOS) in the system. Based on the 802.11b/g multimedia communication system, this article brings forward 802.11UEDCF extensible protocol by analyzing the principles of 802.11DCF and 802...
Multimedia communications over Wireless Local Area Networks like hotspots, are a challenging issue due to the best-effort nature of Internet communications. In a previous work we introduced a Dual-Queue Rate-Controlled mechanism for Access Points (DRAP) in a Hotspot scenario. DRAP has shown to provide some Quality of Service (QoS) guarantees to audio and video traffic flows in the presence of TCP...
In this paper we assess the interference caused by external (uncontrolled) traffic sources upon real-time flows in IEEE 802.11-based mesh networks. Through a set of simulations, we assess the impact of external traffic sources by analyzing the end-to-end delay, frame loss ratio and deadline miss ratio as performance metrics for a set of real-time flows. We infer the maximum interfering traffic load...
Nowadays users have a multitude of ways to connect with other users or applications servers to send and receive data. One of the most used is WIFI and UMTS (3G) networks. These technologies must satisfy users' requirements especially those related to real time applications such as IP telephony or video streaming. Therefore WIFI and UMTS must implement QoS techniques to reach this satisfaction. Both...
One of the today challenges for the mesh networks researches is reliable transmission of multimedia traffic. This traffic demands high quality of service (QoS), to provide which it is suitable to use Mesh Coordinated Channel Access (MCCA) — the novel medium access method described in IEEE 802.11s. According to MCCA, mesh stations (STAs) set up periodic reservations; if all STAs in the network support...
Efficient bandwidth estimation is significant for Quality of Service (QoS) of multimedia services in IEEE 802.11 WLANs. Many bandwidth estimation solutions have been developed such as probing-based technique and cross-layer scheme. However, these solutions either introduce additional traffic or require modification to the standard protocols. This paper develops a model based bandwidth estimation algorithm...
The great potential of Wireless Mesh Networks (WMNs) is their autonomy of being built and formed without the need of any infrastructure. An IEEE 802.11s standard draft has been lately designed to define the WMNs framework and architecture. Multi-channel multi-radio wireless mesh networks (MCMR WMNs) have been introduced to improve system performance. However, interfaces and channels management in...
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