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Peer-to-peer model is one of the commonly used model for distributed computing. Some of the peers are having demand for certain resources some others may be having additional capacity of resources. Peers may have limitations on the number of concurrent connections (degree). In the present work allocation problem of peers having demand, capacity and degree is considered. The problem is to find an allocation...
Multi-path transfer protocols such as Concurrent Multi-Path Transfer for SCTP and Multi-Path TCP (MPTCP), are becoming increasingly popular, due to widespread deployment of smartphones with multi-homing support. Although the idea of using multiple interfaces simultaneously to improve application throughput is tempting, does transmission over multiple interfaces always provide benefits especially in...
In this work, we propose a dynamic Inter-Cell Interference Coordination (ICIC) and scheduling for LTE-A system. The objective is to enhance edge users' throughput and guaranty fairness among all users in the cell. Based on Reference Signal Receiving Power (RSRP) values collected from a set of collaborative base stations, users are classified into: cell edge or cell center. Then, a simple static power...
In this paper, we propose a quality of experience (QoE) aware quality-level switching algorithm for adaptive video streaming. The proposed algorithm is a quality- level switching algorithm which works on the controller of dynamic adaptive streaming over HTTP (DASH) system. The proposed algorithm has two features: insertion of intermediate quality level and limitation of quality-level switching. The...
Multi-antenna OFDMA-SDMA systems provide the required high spectral efficiency and flexibility to support the ever increasing data rates requirements of real-time multimedia applications in future wireless access systems. However, the resource allocation process becomes extremely complex because of the large number of degrees of freedom and the strict timing requirement of real-time traffic. In this...
The exponential back-off mechanism, proposed for reducing MAC- layer contention in the 802.11 standard, is sub-optimal in terms of the network throughput. This back-off mechanism and its improved variants are especially inefficient under unknown dynamics such as packet arrivals and user entry/exit. In this paper, we formulate the problem of optimizing this back-off mechanism as a Markov decision process,...
The idea of in-band full-duplex (FD) communications revives in recent years owing to the significant progress in the self-interference cancellation and hardware design techniques, which offers the potential to double spectral efficiency. However, the adaptations from lower to upper layers are highly demanded in the design of FD communication systems. In this paper, we first propose a novel medium...
IEEE 802.11p is proposed as the VANET wireless MAC interface for the transmissions of emergency messages in V2V and V2I Communications. However, in a high mobility VANET, QoS of both the emergency message (EM) and handoff transmissions suffer from high collision probability of the contention-based media access mechanism and high interference exhibiting near the cell-edge that encodes a low coding...
This paper investigates the resource allocation in terms of sub carrier assignment for maximizing the overall network throughput. In the existing subcarrier assignment algorithm, some users may obtain none of subcarrier while a few number of users with better channels obtain most of the resources. Therefore, we present an algorithm to solve the relay selection and resource assignment with the threshold...
The network resource competition of today' data enters is extremely intense between long-lived elephant flows and latency-sensitive mice flows. Achieving both goals of high throughput and low latency respectively for the two types of flows requires compromise, which recent research has not successfully solved mainly due to the transfer of elephant and mice flows on shared links without any differentiation...
In cellular networks, proximity users may communicate directly without going through the infrastructure such as the base station (BS), which is device-to-device (D2D) communications, and it can improve spectral efficiency. However, enabling D2D communications in a cellular network poses two major challenges. First, the BS is suffered from signaling overhead. Second, D2D transmitters may cause harmful...
In this paper, we study a resource allocation scheme for downlink orthogonal frequency division multiplexing (OFDM) cognitive radio networks (CRNs) in which the cognitive base station (BS) is equipped with multiple antennas. The multiple description coding multicast (MDCM) model and beamforming technique are employed to maximize the total received rate of all cognitive radio (CR) users with the constraint...
In IEEE 802.11-based multihop wireless mesh networks (WMNs), nodes that are a number of hops away from the gateway (GW) face two-fold contentions: namely channel access contention between itself and other nodes, and traffic contention between its own and relayed traffic. As a result, they suffer from low throughput and even starvation, which results in unfairness in transmissions. In this paper, we...
With increasingly popular services containing asymmetric uplink (UL) and downlink (DL) traffic, Time-Division Duplexing (TDD) shows more advantages than Frequency-Division Duplexing (FDD) in wireless cellular networks due to its flexibility of dynamic UL/DL configuration. A major technical challenge in TDD is how to optimize the UL/DL switching point for each individual cell to meet its asymmetric...
Many existing handover mechanisms trigger network selection based on dynamic performance characteristics such as Received Signal Strength (RSS), Delay, and Loss. These approaches do not take into account how the predictability of end user movement can be used to influence and optimize handover selection. Scenarios in which predictable movement can be observed include motorways, public service vehicles...
In multiple hops network, there would be competition among the Peer to Peer (P2P) links when the amount of the P2P links was large. This paper proposed a novel dynamic channel allocation (DCA) algorithm based on ant colony intelligence (ACI) to solve the problem of multi-hop network competition among the P2P links. Theory analysis showed than the shorter of the average length of the routes of the...
Congestion control plays a significant role in maintaining sufficient network throughput. Variety of methods and algorithms are proposed to solve the bottleneck issue. This paper describes a method based on a particle swarm optimization algorithm and piecewise affine controller for non-stationary, discrete, dynamical model of data exchange network. This solution allows active network nodes buffer...
This paper, presents the design and evaluation of security enhancement for data transmission in 4G networks. An enhanced encryption method with AES algorithm is used here. To increase the complexity of the system, AES is used in Round structure and Enhancement is done by modifying the S-box. The static S-box is made dynamic using cipher key and the performance is kept close to the traditional algorithm...
In this paper, we develop an opportunistic scheduling policy for allocating spectrum in cognitive radio networks. We maximize the throughput utility of secondary users subject to maximum collision constraints with the primary users. Particularly, we consider a cognitive radio network with a subset of the secondary users desire to use the licensed channels of primary system in a stochastic environment...
Typically, mobile users cluster around points of interest in dense urban environments such as city centers forming so-called data traffic hot spots and hot zones. To provide capacity to such users efficiently, mobile operators deploy small cells. However, the deployment of heterogeneous networks, which consist of overlaying macro cells and many co-channel small cells, entails many problems. One typical...
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