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.
In cognitive radio, cooperative detection through optimization can improve the performance of spectrum sensing. In this paper, the optimal selection of cognitive radios including threshold optimization and cognitive radio's selection optimization is proposed, and the sensing mechanism including sensing period optimization and sensing time optimization is also analyzed. The proposed optimization algorithm...
We consider a random access primary network. At the beginning of each time slot, a number of secondary users sense the channel and make an access decision based on the spectrum sensing outcome and the channel state information (CSI). Specifically, the channel is accessed by a secondary transmitter with a probability that depends on both the sensing metric and the gain or signal-to-noise-ratio (SNR)...
Spectrum sensing is an essential functionality of cognitive radio networks. In this paper, a noncooperative game framework is proposed for studying the interactions between multiple secondary strategic users in spectrum sensing. The licensed spectrum of single primary user is divided into K sub-bands, each secondary user operates exclusively in one sub-band. In each time interval, secondary users...
The Internet architecture provides a mechanism for protecting individual flows from congestion, by introducing queue management and scheduling algorithms in Input-Queued switches having finite queue size to improve the QoS performance in terms of throughput and delay. Queue management algorithms manage the length of packet queues by dropping packets when necessary or appropriate, while Scheduling...
Owing to the high data rate of IEEE 802.11n, high-definition video transmission becomes one of its major applications. However, it's still difficult for contention-based MAC layer to provide enough QoS guarantee for such latency-sensitive applications. This paper has analyzed the performance on delay, throughput and packet loss rate in error-prone channels based on the frame aggregation mechanism...
In this paper, we propose a variable preamble length-based broadcasting scheme and compare it with a probability-based broadcasting scheme in a wireless sensor network environment. In our work, we show that in dense wireless sensor networks, broadcasting a packet with a small size preamble can give sufficient network-wide data dissemination and significant throughput. The scheme should help conserve...
This paper proposed a novel algorithm based on Kolmogorov-Smirnoff(K-S) algorithm to detect the selfish behavior of nodes. Compared with the detection of transmitted number, the detection performance including speed and precision has been significantly improved. The radio conditions are not needed and capture effect would not impact the performance of the algorithm. Simulation experiments show that...
A good approximate analytical formulation of the saturated throughput of a Cooperative MAC (CoopMAC) is presented via a two-dimensional discrete-time Markov chain rather than using an approximation. A helper node is used to relay packets from the source node to the destination node within a coverage via a faster two-hop link if possible. The analytical model is formulated with a number of data rates...
The wireless network medium has a large, but finite bandwidth. With increasing wireless network service providers, users, and applications, there is a need to optimise usage of even parts of the spectrum that are licensed. Dynamic spectrum access is an approach that is designed to enable unlicensed users to make use of licensed parts of the spectrum, opportunistically, when they are idle. To achieve...
This paper studies the radio capacity improvement provided by an HSPA+ key feature: dual-cell, combined with MIMO. The proposed method combines drive test measurements, link-level simulations, and a queuing theory-based statistical capacity model, thereby providing a reliable estimate of the network radio capacity. Simulation results show that dual cell combined with MIMO and non-linear receivers...
Providing quality of service (QoS) to the passengers at an airport is extremely challenging due to the dynamic nature of the environment in which they operate coupled with their own behaviour. With the regular arrivals and departures of flights, passenger flow tends to continuously change making it more difficult to maintain the required QoS. Moreover, deploying an ad hoc system in such a scenario...
The ubiquitous presence of powerful low-power wireless systems on chip (SoC) able to operate in the Industrial, Scientific and Medical (ISM) band has brought a new enhanced operational choice for real-time Radio Control (RC) applications such as aircrafts and cars in the hobby grade category. Frequency Hopping Spread Spectrum (FHSS) has become the dominant transmission technique for the previously...
In this paper, we study and optimize the cooperation cluster size in cooperative spectrum sensing to maximize the throughput of secondary users (SUs). To calculate the effective throughput, we assume each SU spends just 1 symbol to negotiate with the other SUs in its transmission range. This is the minimum overhead required for each SU to broadcast its sensing decision to the other members of the...
In this paper, we formulate an optimization problem for resource allocation and scheduling in orthogonal frequency division multiple access (OFDMA) half-duplex decode-and-forward (DF) relay assisted networks. Our problem formulation takes into account artificial noise generation to combat a multiple antenna eavesdropper. The secrecy data rate, power, and sub-carrier allocation policies are optimized...
In order to improve the accuracy of analysis, we propose a improved bidimensional Markov chains model for estimating the performance of IEEE802.11 DCF for non-saturated conditions taking into account the impact of channel errors in a non-ideal channel in this paper and then, using the improved model, analyzes the performances of IEEE802.11 DCF Wireless LANs for different channel bit error rate, deriving...
In this paper we describe RED-Random Early Detection which is an active queue management algorithm for congestion control. The basic idea of RED is that one should not wait till the buffer is full in order to detect drop packets but start detecting congestion before the buffer overflows. In this paper we present the performance behavior of RED which it posses under different congestion control schemes...
We propose an efficient cooperative ARQ (Automatic Repeat request) scheme for multi-hop underwater acoustic communications, in which cooperative nodes are used to provide more reliable alternative paths for a specific source-relay-destination connection. Based on the knowledge of inter-node distances, a cooperative region is defined to include all possible candidates for cooperative nodes from a given...
A framework for the joint design of wireless network and controllers is proposed. Multiple control systems are considered where the sensor measurements are transmitted to the controller over the IEEE 802.15.4 protocol. The essential issues of wireless networked control systems (NCSs) are investigated to provide an abstraction of the wireless network for a co-design approach. We first present an analytical...
In this paper, we propose a new semi-Markov process based model to compute the network parameters such as saturation throughput, for the IEEE 802.11 Distributed Coordination Function (DCF) employing the Binary Exponential Backoff (BEB). The backoff stages of BEB and their backoff intervals are modeled as the states of semi-Markov process and their state holding-times, respectively. The proposed model...
There is the problem of absolute discrimination in current Active Queue Management (AQM) algorithms for Differentiated Services, the throughput and link utilization of network are decreased. In this paper we have presented an AQM algorithm, called Weighted-queue-length RIO-C (WRIO). WRIO realizes relative discrimination of different drop precedence, and improves link utilization, especially for the...
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.