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Datagram Congestion Control Protocol (DCCP) is a transport protocol fits for real-time multimedia applications by processing congestion control and unreliable transmission. DCCP takes on a good performance in wired network while causes a substantial decline in wireless networks. This paper analyzes DCCP CCID-3 in wireless ad hoc networks and mainly focuses on two factors that impact the protocol performance...
In this paper, we have extended the GeoDivRP geodiverse routing protocol to consider jitter requirements when using multiple geographic paths for telecommunication networks under regional challenges. We have formulated bounded-jitter multipath routing using a multi-commodity flow problem and proposed an integer linear programming formulation to solve it. We have implemented the routing protocol in...
In a cognitive radio system, proper configuration of sensing duration enables maximization of the data throughput. However, no existing straightforward formula is available, which is desirable in the mobile context due to tightness of computation time. A set of closed-form approximate formulae of optimal sensing duration for cognitive radio are derived under different signal to noise ratio (SNR)....
Power-line communications are becoming a key component in home networking. The dominant MAC protocol for high data-rate power-line communications, IEEE 1901, employs a CSMA/CA mechanism similar to the back off process of 802.11. Existing performance evaluation studies of this protocol assume that the back off processes of the stations are independent (the so-called decoupling assumption). However,...
The wireless environment is unstable. The transmission link always bursts into errors, which makes the head packet fail to be transmitted. This paper gives the fact that choosing the queue with bad error link to transmit the packet will bring about the Head Of Line (HOL) problem: the blocked head packet would make the rest postpone to be sent The HOL problem occurs frequently because of the unstable...
In today's large data centers, hundreds to thousands of nodes are deployed as storage clusters to provide cloud and big data storage service, where failures are not rare. Therefore, efficient data redundancy technologies are needed to ensure data availability and reliability. Compared to traditional technology based on replication, erasure codes which tolerate multiple failures provide availability...
In this paper we propose a scheme to restrain the greedy flows so as to guarantee the Qos of high priority traffics. By applying the ACK mechanism of MAC frames on access points (AP), we establish a dynamic model to analyze the scheme in theory. Furthermore, we obtain the bound of MAC-ACK dropping ratio P of the greedy flows based on the model we proposed. The results that are from the NS2 simulations...
Dynamic spectrum access is an effective approach to improve the spectrum utilization. When primary user (PU) leases its spectrum to secondary users (SU), the spectrum efficiency can be enhanced, however, PU might be interfered by the co-existence of SU. This paper considers the situation that PU is willing to coexist with SU once it is paid and its Signal to Interference-plus-Noise Ratio (SINR) is...
We consider a system of two nodes transmitting to an access point on quasi-static Rayleigh fading channels. We use signal-to-noise ratio (SNR) thresholds to characterize the requirements of each node, in terms of throughput and reliability, and we study their impact on outage probability. Given the average quality of the uplink channels, we formulate conditions on the SNR thresholds for decode-and-forward...
In this paper, we consider the problem of finding the maximum routing throughput between any pair of nodes in an arbitrary multirate wireless mesh network (WMN) using multiple paths. Multipath routing is an efficient technique to maximize routing throughput in WMN, however maximizing multipath routing throughput is a NP-complete problem due to the shared medium for electromagnetic wave transmission...
The authors have proposed a fair solution to optimal rate adaptation. The problem has been described in terms of the objective function, decision variables and constraints. Furthermore, using this problem definition, a rate adaptation heuristic was developed and divided into two sub- problems; part one requires finding the optimal rate allocation within the network, part two continues by finding a...
Improving Quality of Service (QoS) in wireless networks is important and necessary for mobile users. We have previously proposed Comfort Route (CR) Navigation, which navigates users to their destinations using high QoS communication areas, such as Wi-Fi APs, rather than the geographical Shortest Route (SR). In this paper, we employ an analytical model to estimate the CR gain in a theoretical manner...
In this paper, a new admission control scheme is presented based on the proportional admission control scheme of the IEEE802.11aa to solve the problems in the 802.11 WLANS. Quality of service (QoS) and throughput are the most significant questions in the 802.11 WLANS especially when the bandwidth is scare. In the Overlapping Basic Service Set (OBSS), we need to face many problems such as the high...
The Turbo-decoding Message-passing (TDMP) algorithm of Low-Density Parity-Check (LDPC) codes has a faster convergence speed, lower hardware implementation complexity, and less storage units than the Belief-Passing (BP) algorithms. However, because of the integer quantization operations for initial information, restriction of storage units will cause the problem of decoding information overflowing...
Newton-Raphson and Goldschmidt algorithms can be sped up by using variable latency hardware architectures for rounding division, square root and their reciprocals. A new approach based on a rounding method with remainder estimate calculated concurrently with the algorithm was proposed in [5]. This paper presents an study of the hardware implementation of this approach and shows that does not suppose...
Backpressure Routing is a cross-layer control algorithm that makes decisions on routing and resource allocation in mobile ad hoc networks using network state information like queue backlog values and current available channel rates. While it is desirable because of its provable performance guarantees, including providing optimal throughput, the real world problem of implementing backpressure routing...
Cryptographic hash functions have many security based applications, particularly in message authentication codes (MACs), digital signatures and data integrity. Secure Hash Algorithm-3 (SHA-3) is a new cryptographic hash algorithm that was selected on 2nd Oct '12 after a five year public contest organized by the National Institute of Standards and Technology (NIST), USA. This paper provides a unique...
This paper is devoted to modeling and analysis of multi-product manufacturing systems with asynchronous exponential machines and finite non-dedicated buffers. In such systems, each machine may process different types of products with different speeds, and buffers are shared for all products. Analytical methods to evaluate the system performance are developed. Formulas are derived to calculate line...
The small cell network based Heterogeneous Network (HetNet) is featured as the promising way to meet the higher capacity improvement requirements for future. But how to effectively solve the upcoming heavy load and low Energy Efficiency (EE) problem in densely deployment scenario are still the key challenges for the small cell HetNet. In order to solve above problems, we implement the offloading strategy...
In a Wi-Fi Direct network, a single battery-powered mobile device called group owner (GO) helps other mobile devices communicate each other without relying on a pre-existing infrastructure such as base stations. Hence, the Wi-Fi Direct defines two power saving schemes for the energy efficiency of GO, called opportunistic power save (OPS) and notice of absence (NoA). However, the Wi-Fi Direct specification...
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