The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The heterogeneous networks are expected to become a main focus in the development toward the Next Generation Cellular Network (NGCN). The heterogeneous networks will allow users to move freely across different networks. However, the determination of the handoff initiation time is difficult in heterogeneous networks since many factors should be considered in the decision algorithm. Therefore, in this...
The widespread use of heterogeneous wireless network technologies and their integration with multi-mode terminals enable users to be associated to the best available networks according to user preferences and application specific requirements. We study a user-centric quality of experience based resource allocation problem with several operators, several types of users and different classes of services...
Various application services including multimedia applications need efficient multicast technologies, but the IEEE 802.11 protocol, which is currently the most widely used, does not specify the standard on multicast, which is, instead, substituted by broadcast or a combination of unicast. Using broadcast is, however, difficult to judge on the transmission success or fail, because it does not receive...
In this study, we aim to analyse the relationship between various characteristics of a communication system with data and voice call requests. Queuing theory and Markov chain analysis are effectively used for this purpose. Such a study is useful for understanding how the proposed mathematical models behave which represents a system with integrated voice and data calls in homogenous wireless networks...
Response delay problem and measurements of such delays have been reported in Part I. The response delay has a negative impact on the accuracy of spectrum sensing, which is the cornerstone of cognitive radio. In this paper, single-user prediction of channel state is proposed to minimize the negative impact of response delays caused by hardware platforms. Specifically, a modified hidden Markov model...
This paper discusses a wireless control system for cooperative motion of machines, and clarifies the influence of packet loss on the system behavior. In performance evaluation, we focus on the synchronization of the motion of the fellow machines. In addition, using the nature of wireless, a new wireless control method is proposed for maintaining the performance under packet loss conditions. In the...
In this paper, problem of throughput optimization in relay networks where all users transmit their packets on a multiple-access channel is studied by introducing a new Markovian game theoretical solution. Despite the previously reported works, in the proposed model, simultaneously transmitted packets on a multiple-access channel are not always discarded. In this article, the possibility of capturing...
When multicasting through wireless multihop networks, frame losses at the wireless link cause data losses at the application layer because of no ACK (Acknowledgment) at both data link layer and transport layer. The authors propose a novel multicast scheme to reduce data losses at the application layer and to improve reliability. The scheme incorporates a retransmission mechanism into the data link...
Handover efficiency in wireless and mobile communication networks is an important factor in providing QoS guarantees for real time applications. The 802.11 standard requires a Mobile Node (MN) to scan all the possible channels (11 in the US) to discover available Access Points (AP's) during a handover. In a given 802.11 cell several channels are expected to be empty. Due to a full scan the MN ends...
Scheduling is a fundamental component in resource (bandwidth and power) management in NG wireless networks and plays the main role in providing QoS requirements such as delay, throughput and packet loss for different classes of service in 802.16d networks. In this paper we propose a novel scheduling algorithm Strict Priority Based Adaptive modulation and Coding (SP_AMC_Based) that can grantee QoS...
Concurrent Multipath Transmission (CMT) mechanisms have been proposed to improve the transmission performance by means of concurrently transmitting data packets via two or more network interfaces. Based on the wireless cognitive radio, that can dynamically adjust the transmission parameters of the specified device, the required CMT mechanism in the wireless environment differs from that in the wired...
Many studies have shown that Vegas TCP has a better throughput and stability than Reno TCP in homogeneous networks with a single TCP flavor, but performs less well in heterogeneous networks in which two TCP flavors coexist. The progressive behavior of Reno TCP and the conservative behavior of Vegas TCP cause a bias when they are used simultaneously, and thus Vegas TCP fails to obtain a fair share...
We study the impact of time-correlated arrivals on the performance of backpressure policy for stochastic network control. The arrival process considered in this work is fairly general in the sense that it may exhibit short/long-range dependence depending on the asymptotic shape of the autocorrelation function. In this paper, we show that that the backpressure policy stabilizes the network whenever...
In interworked fixed and mobile networks, both terminal mobility (TM) and personal mobility (PM) should be supported and interworked to provide seamless universal mobility to mobile users. TM supports movement between different locations with the same mobile terminal (MT). In TM management, an MT updates its location when it changes location area (LA) and an incoming call is delivered to the MT by...
Various transmission control protocol (TCP) enhancement schemes have been proposed to improve TCP performance over mixed wired/wireless networks. Among the different kinds of TCP enhancement schemes, end-to-end TCP enhancement schemes have the lowest implementation complexity and do not violate the semantics of TCP. Their general principle is to distinguish wireless loss from congestion loss, and...
We study the performance of cognitive (secondary) users in a cognitive radio network which uses a channel whenever the primary users are not using the channel. The usage of the channel by the primary users is modelled by an ON-OFF renewal process. The cognitive users may be transmitting data using TCP connections and voice traffic. The voice traffic is given priority over the data traffic. We theoretically...
Modern wireless networks, such as WiMAX or LTE are using OFDM/OFDMA as the enabling technologies for broadband transmission in cellular environments with QoS capabilities. In these networks, such schema as radio resource management, admission control, scheduling are essential. In this article we firstly introduce a Time-Frequency Burst Mapping algorithm for radio resource management that improves...
Network coding can significantly improve the throughput and power efficiency of wireless networks by mixing packets from different flows into a single packet. However, forcing packets to be coded may induce large delay and packet-loss rate which is intolerable to some services such as real-time communications. Considering the diversity of traffic flows and the stochastic nature of the packet arrival...
Stringent QoS maintenance in a wireless environment for VoIP communication is a major challenge. VoIP inherently generates constant bit rate traffic and is highly sensitive to network delay. However, unpredictable network congestion makes a VoIP session so degraded that its QoS goes below a tolerable limit. Accordingly, a suitable solution is needed to adapt varying network conditions satisfying minimum...
In a wireless domain where a mobile user accesses heterogeneous wireless technologies with multiple interfaces, a multi-path scheduling algorithm can benefit mobile users' experience by aggregating different network bandwidth together. However, existing literature actually shows that for TCP flows, it may not be the case. To better exploit multi-path scheduling for TCP connections, this paper presents...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.