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2G無線電頻譜回收之研究:以澳門「全城3G」為例 / A Study on 2G Spectrum Reallocation in Macau黃首豪, Wong, Sao Hou Unknown Date (has links)
澳門電信管理局在2012年1月推出「全城3G」計劃,規定2012年7月8日停用所有GSM服務,16萬2G用戶要在半年內轉移到3G服務,但是外地遊客仍可繼續在澳門使用2G漫遊服務,政府希望透計劃推動3G服務的發展,讓無線電資源更具效率地利用,然而在計劃推行期間澳門出現多宗電信故障,加上澳門廉政公署就「全城3G」計劃所發表的調查報告指有關計劃過份介入市場運作,使得本地用戶失去選擇權,損害用戶及業者的權益,而且不符合公共利益,最終「全城3G」計劃無法如期實行,各業者的2G執照與其3G執照一同延長有效期至2023年6月4日。
本研究利用文獻分析法,透過蒐集澳門「全城3G」計劃的相關資料,分析澳門「全城3G」計劃的得失,與此同時借鏡與澳門政治體制相似的香港政府的頻譜政策,檢視兩地政府在回收2G頻譜的成效。本研究綜合分析下發現澳門與香港回收2G頻譜最大的差異在於香港回收的是兩個閒置的CDMA及TDMA系統,對業者有一定的影響,但是影響民眾的範圍卻很小,而且給予3年緩衝的時間讓業者轉移用戶,而澳門則是停用一個在世界上仍算主流的GSM服務,而且要在半年內轉移十多萬用戶到3G,加上在過渡期間出現5宗電信故障,讓民眾質疑計劃的可行性,最終把技術問題變成社會問題。因此本研究建議政府未來要避免直接介入市場,以間接的方式例如徵收階梯式的頻譜使用費來推動行動通訊業發展,回收頻譜時要以平穩適度的方式進行,以及提高電信故障的罰款。 / In January 2012, the Telecommunications Regulation Bureau of Macau (DSRT) announced its decision to scrap the city’s 2G network and rely solely on 3G capabilities. Effective on July 8, 2012, the policy change left about 160,000 local users without 2G service, primarily affecting local tourists still on the 2G roaming network. DSRT stated that the objectives of its decision were to create more investment opportunities and to facilitate the adequate diversification of economic development. However, during this time, two mobile operators failed to provide stable and adequate network services and the Commission Against Corruption (CCAC) of Macau stated that DSRT’s decision deprived consumers of their right to choose their own cellular network and their right to fair treatment. This prompted the 2G service cancellation to be further postponed until June 4, 2023.
This study used literature analysis to review the termination of the 2G mobile network in Macau, and to examine the 2G spectrum reallocation in Hong Kong. This study found that Hong Kong terminated two unused mobile network services (CDMA and TDMA), while Macau is planning to scrap a GSM service which will affect about 150,000 users in Macau. Therefore, opposition to network terminations are greater in Macau than in Hong Kong. At the same time, the failure to provide adequate mobile services by two network operators in Macau led to public mistrust of the government. This study suggests that 1) the DSRT should not have used administrative means to force consumers into using a specific mobile system, and 2) the DSRT should have amended the penalties for mobile operators to closer reflect the current social situation.
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Proteção compartilhada e restauração de tráfego em redes ópticas de segmentação espectral flexível / Shared protection and traffic restoration in elastic optical networksNatália Santa Bárbara Capelari 05 May 2016 (has links)
A busca de sistemas de comunicação eficientes e econômicos é cada vez maior, principalmente com o aumento da demanda por tráfego e banda de transmissão. Conhecidas pela utilização eficiente de largura de banda, as redes ópticas de segmentação espectral flexível têm sido intensamente estudadas e são consideradas boas candidatas para a próxima geração de redes. Tais redes flexíveis utilizam formatos de modulação multinível e multiplexação multiportadora. Sistemas com alta capacidade de transmissão devem ser extremamente confiáveis, pois a falha em um dispositivo ou enlace da rede acarreta enorme perda de dados. Por isso, as técnicas de proteção e restauração do tráfego devem ser eficientes, de modo a garantir a sobrevivência da rede. Neste trabalho, foi desenvolvido um algoritmo capaz de lidar com cada requisição de conexão, encontrar um caminho óptico para transmissão e reservar outro caminho para recuperação do tráfego em caso de falha na rede. A seleção dos caminhos primário e de proteção utiliza a técnica smart-fit, que escolhe a solução com menor custo final, definido pela distância da rota percorrida somada ao custo do índice inicial da faixa espectral alocada, buscando equilibrar a escolha entre a posição no espectro e rota escolhida. Além disso, são definidos custos diferentes para slots de frequência livres e compartilhados, a fim de incentivar o compartilhamento espectral em caminhos de proteção. Dentre as técnicas de alocação espectral, a varredura com janela espectral varre o espectro em todos os enlaces da rota, slot por slot, em busca de uma faixa livre com tamanho suficiente para atender uma demanda. Neste trabalho, foi desenvolvida uma técnica chamada busca lógica, que lida simultaneamente com todos os enlaces da rota ao realizar operações lógicas com seus espectros. Em seguida, é realizada uma convolução entre a janela espectral, com tamanho da demanda, e o espectro resultante. A partir desse resultado, é possível saber as posições no espectro onde a demanda poderá ser alocada. Tal técnica, como será demonstrado, é mais veloz que a varredura com janela espectral. Para garantir a eficácia e confiabilidade do algoritmo, utilizando o software MATLAB, avaliou-se a probabilidade de bloqueio e probabilidade de bloqueio de banda, a fragmentação espectral média na rede, o grau de compartilhamento, a taxa de utilização espectral e a taxa de capacidade reservada. O algoritmo desenvolvido foi capaz de organizar o tráfego na rede de modo ordenado e pouco fragmentado, além de utilizar de maneira eficiente os recursos destinados à proteção. / The search for efficient and economical communication systems is increasing, especially with the increased demand for traffic and bandwidth transmission. The elastic optical networks, well known for their efficient using of bandwidth, have been thoroughly studied and are considered good candidates for the next generation networks. Such flexible networks use multilevel modulation formats and multicarrier multiplexing. Systems with high transmission capacity should be extremely reliable, as a failure in a device or link brings huge data loss. Therefore, traffic protection and restoration techniques should be efficient, to ensure network survivability. In this work, we propose an algorithm capable of managing each connection request, finding an optical path for transmission and a protection path to recover traffic in case of network failure. The selection of the primary and protection path uses the smart-fit technique, which chooses the solution with the lower final cost, defined by the route\'s distance plus the index\'s cost of the first slot of the allocated spectrum, in order to balance the choice between the position in the spectrum and the chosen route. In addition, different costs for free or shared frequency slots are defined, so as to encourage spectral sharing in protection paths. Among the spectrum allocation techniques, scanning with spectrum window scans the spectrum in all links of the route, slot by slot, searching for a free band large enough to meet the demand. In this work, we developed a new technique, called logical search, that simultaneously deals with all the links in the route, by performing logical operations with them. Then, a convolution is performed between a spectrum window, with the same size of the demand, and the resulting spectrum. From this result, it is possible to know all the positions in the spectrum where the demand may fit. This technique, as will be shown, is faster than the scan with spectrum window. To guarantee the efficiency and reliability of the algorithm, using the MATLAB software, we evaluated the blocking probability and bandwidth blocking probability, the average spectral fragmentation in the network, the shareability ratio, the spectral utilization ratio and the spare capacity ratio. The developed algorithm was able to organize the traffic in an orderly and less fragmented way, and use the protection resources efficiently.
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Compara??o de estrat?gias de acomoda??o espectral e desfragmenta??o em redes ?pticas el?sticas / Accommodation strategies comparison spectral and defragmentation in elastic optical networksMar?al, Juliano Silva 27 June 2016 (has links)
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Previous issue date: 2016-06-27 / Pontif?cia Universidade Cat?lica de Campinas ? PUC Campinas / In the current technological environment from the point of view of optical transmission, multiplexing technologies for wavelength division (Wavelength Oivision Multiplexing - WOM) working with fixed 50 GHz grid will not support the existing demand for the next 10 years. This scarcity occurs due to several reasons: channels with fixed width of 50 GHz, limitation of 80 optical channels per link, maximum transmission capacity of 100 Gb / s per channel. In search of viable forward solutions to this paradigm that presents technology proposal comes known as Optical Networks Elastic (Elastic Optical Network - EON), a technology that enables optical channels with bandwidths of 3,125, 6,250, 12,500, 25 and 50 GHz transmission capability of rates supported by the WOM yet rates of 200 Gb / s, 400 Gb / s and 1 Tb / s, and can be implemented on the same optical infrastructure WOM already existing thus corresponding to a highly cost less if compared to deployment of new networks. The efficiency of this proposed new technology is mainly in routing algorithms and spectral assignment (Routing and Spectrum Assignment - RSA) aimed at maximizing network availability of resources by reducing the likelihood of blocking. The use of RSAs on the EONS networks fragmentation results in the generation of reducing the availability of network resources. Within this scenario, the present work-studies the feasibility of defragmentation use based on the relocation of the link to submit further fragmentation indexo This paper studies the adoption of two indices: consecutiveness index and more FSUs index busy, both indexes allow the selection of the link to be defragmented. The results of this study were obtained from the development of version 5 of the simulator Elastic Optical Network Simulator (EONSim). To obtain the results, different transmission rates were evenly distributed for each traffic load between 45 and 100 Erlang (E), the First-Fit RSA (FF) was adopted for ali the simulations to reduce the defragmentation processing were performed from an R number of released connections (R = 10, R = 50 and R = 100). For the scenario using the consecutiveness index gain of up to 44 was measured to 55 E and average gain of 15 compared to results without defragmentation scenario for the use of higher index number of occupied FSUs, gain was observed 26 to 55 E and average gain of 10. From the results it can be concluded that the adoption of defragmentation strategies for eons networks are likely to be used since they have decreased blocking probability and increase the availability of network resources. / Na atual conjuntura tecnol?gica do ponto de vista de transmiss?es ?pticas, as tecnologias de multiplexa??o por divis?o de comprimento de onda (Wavelength Oivision Multiplexing - WOM) que trabalham com grade fixa de 50 GHz n?o ir?o comportar a demanda existente para os pr?ximos 10 anos. Esta escassez ocorre por v?rios motivos: canais com largura fixa de 50 GHz, limita??o de 80 canais ?pticos por enlace, capacidade m?xima de transmiss?o de 100 Gb/s por canal. Em busca de solu??es vi?veis frente a este paradigma que se apresenta, surge a proposta da tecnologia conhecida como Redes ?pticas El?sticas (Elastic Optical Network- EON), uma tecnologia que permite canais ?pticos com larguras de banda de 3.125, 6.250, 12.500, 25 e 50 GHz, capacidade de transmiss?o das taxas suportadas pela tecnologia WDM e ainda taxas de 200 Gb/s, 400 Gb/s e 1 Tb/s, e podem ser implantadas sobre a mesma infraestrutura ?ptica WDM j? existente correspondendo assim a um custo altamente inferior se comparado a implanta??o de novas redes. A efici?ncia desta nova proposta de tecnologia est? principalmente nos algoritmos de roteamento e atribui??o espectral (Routing and Spectrum Assignment - RSA) que visam a maximiza??o dos recursos de disponibilidade da rede atrav?s da diminui??o da probabilidade de bloqueio. O uso do RSA resulta na gera??o de fragmenta??o diminuindo a disponibilidade de recursos da rede. Dentro deste cen?rio, o presente trabalho estuda a viabilidade do uso de desfragmenta??o baseada na realoca??o sobre o enlace que apresentar maior ?ndice de fragmenta??o e analisa a ado??o de dois ?ndices: ?ndice de consecutividade e ?ndice de maior n?mero de FSUs ocupados, para a sele??o do enlace a ser desfragmentado. Os resultados deste estudo foram obtidos a partir do desenvolvimento da vers?o 5 do simulador Elastic Op tica I Network Simulator (EONSim). Para a obten??o dos resultados, diferentes taxas de transmiss?o foram distribu?das uniformemente para cada uma carga de tr?fego entre 45 e 100 erlang (E), o RSA First-Fit (FF) foi adotado para todas as simula??es, para diminuir o processamento as desfragmenta??es foram executadas a partir de um n?mero R de conex?es liberadas (R= 10, R= 50 e R= 100). Para o cen?rio utilizando o ?ndice de consecutividade, foi aferido ganho de at? 44 para 55 E e ganho m?dio de 15 quando comparado aos resultados do cen?rio sem desfragmenta??o, para o uso do ?ndice de maior n?mero de FSUs ocupados, foi observado ganho de 26 para 55 E com ganho m?dio de 10. A partir dos resultados obtidos ? poss?vel concluir que a ado??o de estrat?gias de desfragmenta??o para redes EONs s?o pass?veis de serem utilizadas pois apresentam diminui??o da probabilidade de bloqueio e aumento da disponibilidade dos recursos da rede
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Αλγόριθμοι δρομολόγησης και δέσμευσης φάσματος λαμβάνοντας υπόψη τις εξασθενήσεις φυσικού επιπέδου σε οπτικά δίκτυα ορθογώνιας πολυπλεξίας διαίρεσης συχνότηταςΣούμπλης, Πολυζώης 09 July 2013 (has links)
Τα οπτικά δίκτυα αποτελούν την αποδοτικότερη επιλογή όσον αφορά την εγκατάσταση ευρυζωνικών δικτύων κορμού, καθώς παρουσιάζουν μοναδικά χαρακτηριστικά μετάδοσης. Διαθέτουν τεράστιο εύρος ζώνης, υψηλή αξιοπιστία, ενώ επίσης έχουν μειωμένο κόστος μετάδοσης ανά bit πληροφορίας σε σχέση με τα υπόλοιπα ενσύρματα δίκτυα.
Τις τελευταίες δεκαετίες διατυπώθηκαν οι αρχές μίας τεχνολογίας μετάδοσης πολλαπλών φερουσών, γνωστής ως Ορθογώνια Πολυπλεξία Διαίρεσης Συχνότητας (Orthogonal Frequency Division Multiplexing - OFDM), η οποία στηρίζεται στην πολυπλεξία διαίρεσης συχνότητας, αλλά πετυχαίνει πολύ καλύτερη χρησιμοποίηση του διαθέσιμου εύρους ζώνης.
Πρόσφατα και στις οπτικές επικοινωνίες άρχισε να μετατοπίζεται το ενδιαφέρον στην Οπτική Ορθογώνια Πολυπλεξία Διαίρεσης Συχνότητας (O-OFDM), λόγω της προόδου στην κωδικοποίηση και στην ηλεκτρονική ψηφιακή επεξεργασία σήματος (DSP). Οι εξελίξεις αυτές μπορούν να αλλάξουν ριζικά τα οπτικά δίκτυα.
Μέσω της πολυπλεξίας υποφερουσών και της δέσμευση μεταβλητού φάσματος, που είναι χαρακτηριστικά της O-OFDM τεχνολογίας, ένα οπτικό μονοπάτι μπορεί να χρησιμοποιεί το απολύτως απαραίτητο φάσμα (αριθμό υποφερουσών) ανάλογα με το μεταδιδόμενο ρυθμό δεδομένων. Με τον τρόπο αυτό επιτυγχάνεται καλύτερη χρησιμοποίηση φάσματος αναιρόντας τον περιορισμό σταθερού πλέγματος των δικτύων πολυπλεξίας μήκους κύματος (WDM). Παράλληλα η αρχιτεκτονική αυτή υποστηρίζει τη δέσμευση χωρητικότητας μικρότερης ή μεγαλύτερης από αυτή ενός μήκους κύματος μέσω της δέσμευσης κατάλληλου αριθμού υποφερουσών από κατάλληλους transponders και μεταγωγείς WXCs.
Στην παρούσα διπλωματική εργασία αντιμετωπίζεται το πρόβλημα της σχεδίασης ευέλικτων OFDM οπτικών δικτύων, όπου οι αιτήσεις εξυπηρετούνται από κατάλληλους transponders όσον αφορά την επιλογή του χρησιμοποιούμενου φάσματος και του επίπεδου διαμόρφωσης. Με δεδομένη την τοπολογίας του δικτύου, τον πίνακα αιτήσεων και των χαρακτηριστικών των transponders, παρουσιάζονται οι μοντελοποιήσεις γραμμικού ακέραιου προγραμματισμού (Integer Linear Programming) για την επίλυση του προβλήματος σχεδίασης διαφανών (transparent) και ημι-διαφανών (translucent) οπτικών OFDM δικτύων λαμβάμνοντας υπόψη τους υπαρκτούς περιορισμούς φυσικού επιπέδου. Σχεδιάζεται λοιπόν, ένα πρόβλημα βελτιστοποίησης που λαμβάνει υπόψη του τόσο το εύρος ζώνης που χρησιμοποιείται όσο και τον αριθμό των transponders. Από τη στιγμή που το πρόβλημα της δρομολόγησης και δέσμευσης φάσματος (Routing and Spectrum Allocation RSA) είναι ΝP πλήρες (NP-complete), η λύση του προβλήματος γραμμικού ακέραιου προγραμματισμού (ILP) δεν είναι αποδοτική για μεγάλα στιγμιότυπα του προβλήματος. Για το λόγο αυτό, παρουσιάζονται ευριστικοί αλγόριθμοι (heuristic algorithms) για την επίλυση του προβλήματος σχεδίασης διαφανών και ημι-διαφανών οπτικών δικτύων. / We consider the planning problem of a spectrum flexible optical network where traffic is served by flexible transponders that can be tuned in both the spectrum and the modulation format that they utilize. We assume that physical layer impairments are incorporated in the definition of the feasible transmission configurations for the transponders, described by capacity-reach-spectrum-guardband tuples. Given the feasible configurations (tuples) of the transponders and the traffic matrix, we formulate the planning problem of a spectrum flexible optical network considering both the use or not of regenerators in the network. Demands are served for their requested rates by choosing the route, breaking the transmission in more than one connection if needed, placing regenerators if needed, and allocating spectrum to the connections. The connections are separated by appropriate spectrum guardbands so that physical layer interference is kept at acceptable levels. The objective is to serve the traffic and find a solution that is Pareto optimal with respect to the total amount of spectrum utilized and the number of transponders used. We start by presenting algorithms that are based on integer linear programming (ILP) formulations for planning both transparent (without regenerators) and translucent (with regenerators) networks and then we continue by presenting heuristic algorithms. Our heuristic algorithms utilize simulated annealing to tradeoff performance with running time. We use transmission tuples based on studies on OFDM-based networks in our simulation experiments. We initially examine the optimality performance of the heuristic algorithms in small scale experiments. Then we use the heuristic algorithms to study realistic network planning problems and evaluate the spectrum and transponder cost savings that can be obtained by an OFDM-based network as compared to a mixed line rate (MLR) fixed-grid WDM optical network.
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Heterogenní propojení mobilních zařízení v bezdrátových systémech 5. generace / Heterogeneous Connectivity of Mobile Devices in 5G Wireless SystemsMašek, Pavel January 2017 (has links)
Předkládaná disertační práce je zaměřena na "heterogenní propojení mobilních zařízení v bezdrátových systémech 5. generace". Navzdory nepochybnému pokroku v rámci navržených komunikačních řešení postrádají mobilní sítě nastupující generace dostatečnou šířku pásma a to hlavně kvůli neefektivnímu využívání rádiového spektra. Tato situace tedy v současné době představuje řadu otázek v oblasti výzkumu. Hlavním cílem této disertační práce je proto návrh nových komunikačních mechanismů pro komunikaci mezi zařízeními v bezprostřední blízkosti s asistencí mobilní sítě a dále pak návrh a implementace algoritmů pro dynamické přidělování frekvenčního spektra v nastupujících mobilních sítích 5G. Navrhnuté komunikační mechanismy a algoritmy jsou následně komplexně vyhodnoceny pomocí nově vyvinutých simulačních nástrojů (kalibrovaných s využitím 3GPP trénovacích dat) a zejména pak v experimentální mobilní síti LTE-A, která se nachází v prostorách Vysokého učení technického v Brně, Česká Republika. Získané praktické výsledky, které jsou podpořeny zcela novou matematickou analýzou ve speciálně navržených charakteristických scénářích, představují řešení pro vlastníka spektra v případě požadavků na jeho dynamické sdílení. Tato metoda tedy představuje možnost pro efektivnější využití spektra v rámci mobilních sítí 5G bez degradace kvality služeb (QoS) a kvality zážitků (QoE) pro koncové uživatele. Vědecký přínos dosažených výsledků dokazuje fakt, že některé z principů představených v této disertační práci byly zahrnuty do celosvětově uznávaného standardu (specifikace) 3GPP Release 12.
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