Abstract

Keywords

References

Abstract

In this paper, the traditional ant colony algorithm has a slow convergence rate for routing optimization of Mesh networks. A multi-path routing protocol based on improved ant colony algorithm, Fortified Ant protocol, is proposed. The protocol first adds a sorting algorithm based on the ant colony algorithm, and introduces the concept of elite ants to improve the speed of routing optimization. Secondly, this paper also studies the multipath transmission of self-organizing networks. The simulation results show that compared with ADOV, DSR and AOC routing algorithms, the algorithm can quickly find multiple paths with better quality, with fast convergence and overhead. Less advantage.

1. Introduction

Wireless Mesh network is a kind of self-organizing network, mainly composed of two parts, respectively is wireless router (Mesh routers) and wireless client (Mesh clients), Mesh router constitute the backbone network, Mesh clients through the Internet backbone network connection.Under the communication environment of wireless mesh network, the topology of mesh network is relatively stable, so it has great research value in the temporary arrangement of communication network.

As the future of wireless Mesh networks has gradually been recognized by many scholars, many experts have studied the multipath routing methods of wireless Mesh networks, and many have achieved certain results. In [1], a multi-path routing discovery method based on particle swarm optimization for wireless mesh networks is proposed. The congestion prediction degree and node forwarding goodness function are defined as the fitness function of the particle swarm algorithm model to ensure the validity of the calculated path. High efficiency. Literature [2] mainly studies the feasibility of ant colony algorithm applied to route optimization in Mesh networks. Simulation experiments show that ant colony algorithm can be used for route optimization of Mesh networks, and its optimization speed is fast, and it can achieve global optimization.

In this paper, on the basis of above research, in view of the traditional Ant colony algorithm optimization is slow and single path routing is easy to lose data grouping problem, put forward a kind of Ant colony algorithm based on sorting multipath routing protocols – Fortified Ant protocol.

In this paper, a pk-adaptive mesh refinement of pseudospectral method is proposed for solving optimal control problem by using collocation at Legendre-Gauss-Lobatto (LGL) points, motivated by reducing the redundant collocation points in the state-of-art mesh refinement methods to improve the time efficiency. The proposed method involves three phases, i.e., the determination of the polynomial degree, the determination of increasing intervals or nodes, and the optimization of the locations of segment breaks in each interval. First, determines the polynomial degree by the error estimation between the dynamics and the differentiation approximation of state variables according to the spectral matrix. Second, the maximum allowed polynomial degree in an interval is used to decide whether to segment interval or not. Third, the locations of segment points are obtained as the optimal design parameters of optimal control method. The terminology ‘‘pk-adaptive’’ or ‘‘p-then-k adaptive’’ is used because the polynomial degree is preferentially adaptive variation, then increases the segments by adding the optimal knots in each mesh interval. Finally, the residual of solutions, number of segments, number of nodes, CPU time, convergence of iteration, and parameters of the method have been analyzed in the comparing test to discuss the advantages of pk-adaptive mesh refinement. The discussions performed in two examples and demonstrated that the pk-adaptive method has the ability of optimizing nodes distribution to keep fewer nodes requirement and higher time efficiency than the hp- or ph-based pseudospectral methods while achieving the equivalent accuracy.

Introduction

Pseudospectral methods is widely used in the numerical solution of nonlinear optimal control problem [1], whose examples range from missiles’ dive phase trajectory maneuver [2], control of wave energy converters [3], trajectory optimization of boost-glide vehicle [4], trajectory design for lunar landing [5], etc. One of the key points for the wide application of pseudospectral method is the spectral accuracy of exponential convergence in differential approximation theory [6]. The selection of orthogonal basis functions and the orthogonal quadrature rules are two important factors to determine the nodes distribution for differential approximation with few discrete points [7]. Three orthogonal polynomials, i.e., Legendre [8], Chebyshev [9] and Laguerre [10], are commonly used as the basis functions. And three commonly used orthogonal quadrature rules are Gauss [11], Gauss-Radau [12], and Gauss-Lobatto [13]. By combining the above two factors, a pseudospectral method can be obtained to solve the nonlinear optimal control problems. For example, the LegendreGauss-Lobatto (LGL) pseudospectral method [14] combines Gauss-Lobatto quadrature with the Legendre polynomials according to the collocation points, which are known as LGL nodes. There is no definite evidence for the superiority of the selection of orthogonal basis functions between Legendre and Chebyshev, but Laguerre is the only one to be normally discussed for solving the infinite time problems [15]. Fahroo and Ross [16] discussed the application conditions of three orthogonal quadrature rules based on Legendre pseudospectral method and argued that Gauss-Lobatto should be used more in addition to special boundary problems.

Emerging Trends in Networks and Computer Communications International Conference

در مناطق روستایی در آفریقا، شرایط متفاوت جغرافیایی، شامل  مناطق پر از تپه یا مناطق هموار ، بوته ها ، درختان و  گیاهان می شوند. در بعضی  موارد، شرایط زیر ساختی و جاده بسیار ضعیف هستند، آن را برای ارائه ی ضرورت تعمیر و نگهداری و پشتیبانی شبکه های ارتباطی چالش برانگیز و هزینه بر می سازد. وقتی یک گره به صورت آفلاین می رود گره های باقی مانده بایستی برای برقراری دوباره ی لینکها با هر یک و حفظ اتصال  توانا باشند. پروتکل مسیریابی باید کوتاه ترین مسیر جایگزین را پیدا کند و این مسیر را برای ارائه ی داده ها استفاده کند.  زمان تعمیر و نگهداری می تواند  کند باشد و ممکن است چند روز  برای مراجعه به گره ی معیوب در یک منطقه ی روستایی را بگیرد. با توجه به این، شبکه باید قادر باشد برای مدت طولانی با گره(ها) معیوب عمل کندو بهترین کیفیت ممکن از خدمات را ارائه دهد. در چند سال گذشته، شبکه های بی سیم مش (MWNs)  افزایشی در پژوهش و استفاده  به دلیل  مشخصات جذاب آنها که شامل هزینه استقرار کم را جلب کرده اند، که شامل هزینه ی گسترش که می باشد، یک هزینه ی کم گزینه ای برای پوشش شبکه ی گسترده و سهولت نگهداری با توجه به خصوصیات  خودشناسی آنها می باشد. در MWNs  یک افزایش در مقیاس پذیری، توان عملیاتی شبکه به کاهش تمایل دارد .در این مقاله، ما یک تجزیه و تحلیل عملکردی را  برای سناریوهای گره شکست و برای شبکه های دور سنجی روستایی با استفاده از سه پروتکل مانند، OLSR(یک پروتکل فعال)، DSR(یک پروتکل واکنشی) و HWMP(یک پروتکل ترکیبی)،انجام داده ایم. تجزیه و تحلیل عملکردی از این پروتکلها ، با استفاده از سه سناریوی توپولوژی شبکه بک هال (backhaul) صورت گرفته است. نتایج مشابه با استفاده از OMNET++ و چارچوب INETMANET  به دست آمده اند. معیارهای عملکردی برای تجزیه و تحلیل استفاده شدند و گم کردن بسته(packet loss) و تاخیر end-to-end  را مطالعه می کند. همچنین اینها فاکتورهای مهم در نظر گرفته شده  برای ارائه کیفیت تضمین شده از خدمات هستند (QoS).