The high deployment and maintenance costs of last mile wireline networks (i.e., DSL and cable networks) have urged service providers to search for new cost-effective solutions to provide broadband connectivity. Broadband wireless access (BWA) networks, which offer a wide coverage area and high transmission rates in addition to their fast and low-cost deployment, have emerged as an alternative to last mile wireline networks. Therefore, BWA networks are expected to be deployed in areas with different terrain profiles (e.g., urban, suburban, rural) where wireless communication faces different channel impairments. This fact necessitates the adoption of various transmission technologies that combat the channel impairments of each profile. Implementation scenarios of BWA networks considered in this thesis are multicarrier-based direct transmission and single carrier-based cooperative transmission scenarios. The performance of these transmission technologies highly depends on how resources are allocated. In this thesis, we focus on the development of practical resource allocation schemes for the mentioned BWA networks implementation scenarios. In order to develop practical schemes, the imperfection of channel state information (CSI) and computational power limitations are among considered practical implementation issues. The design of efficient resource allocation schemes at the MAC layer heavily relies on the CSI reported from the PHY layer as a measure of the wireless channel condition. The channel estimation error and feedback delay renders the reported CSI erroneous. The inaccuracy in CSI propagates to higher layers, resulting in performance degradation. Although this effect is intuitive, a quantitative measure of this degradation is necessary for the design of practical resource allocation schemes. An approach to the evaluation of the ergodic mutual information that reflects this degradation is developed for single carrier, multicarrier, direct, and cooperative scenarios with inaccurate CSI. Given the CSI estimates and estimation error statistics, the presented evaluation of ergodic mutual information can be used in resource allocation and in assessing the severity of estimation error on performance degradation. A point-to-multipoint (PMP) network that employs orthogonal frequency division multiple access (OFDMA) is considered as one of the most common implementation scenarios of BWA networks. Replacing wireline networks requires not only providing the last mile connectivity to subscribers but also supporting their diverse services with stringent quality of service (QoS) requirements. Therefore, the resource allocation problem (i.e., subcarriers, rate and power allocation) is modeled as a network utility maximization (NUM) one that captures the characteristics of this implementation scenario. A dual decomposition-based resource allocation scheme that takes into consideration the diversity of service requirements and inaccuracy of the CSI estimation is developed. Numerical evaluations and simulations are conducted to validate our theoretical claims that the scheme maximizes resource utilization, coordinates with the call admission controller to guarantee QoS, and accounts for CSI inaccuracy. Cooperation has recently received great attention from the research community and industry because of its low cost and fast deployment in addition to the performance improvement it brings to BWA networks. In cooperative scenarios, subscribers cooperate to relay each other's signals. For this implementation scenario of BWA networks, a robust and constrained Kalman filter-based power allocation scheme is proposed to minimize power consumption and guarantee bit error probability (BEP) requirements. The proposed scheme is robust to CSI inaccuracy, responsive to changes in BEP requirements, and optimal in allocating resources. In summary, research results presented in this thesis contribute to the development of practical resource allocation schemes for BWA networks.

In recent years, the ever-increasing environmental friendliness concern has made energy efficiency in telecom networks as an important theme in their operations. Meanwhile, mission-critical (MC) services and systems (such as healthcare, police, and firefighting) have been acquiring special attention from telecom designers and operators. The currently deployed MC network technologies are indigent in terms of bandwidth capacity, and thus they are not able to support the emerging MC multimedia applications. Therefore in this thesis, we first explore the possibility of provisioning the MC services over the integration of fiber-wireless (FiWi) technologies, which has been considered as a promising candidate for the deployment of high-speed and mobile broadband access networks. We then investigate the energy efficiency problem in the FiWi integration, which consists of WiMAX in the wireless plane, and of Ethernet Passive Optical Network (EPON) - the most popular variant of the next-generation PON (NG-PON) technology, in the optical plane. In WiMAX, the energy saving protocol has been extensively investigated and standardized. Conversely, it has been recently studied in NG-PON, which currently consumes the least power among all the high-speed access networks. However, NG-PON has notably matured in the past few years and is envisioned to massively evolve in the near future. This trend will increase the power requirements of NG-PON and make it no longer coveted. Therefore we address the energy efficiency problem in NG-PON. For each of our contributions, we conduct extensive simulations to demonstrate the effectiveness and advantages of the proposed solutions.

WiMAX is one of the rising communications technology which enables last mile broadband mobile wireless Internet connectivity. IEEE Std 802.16-2009 is the last accepted standard which targets mobile and fixed wireless broadband access. The standard defines two types of stations which are base and mobile stations. A base station has a wired connection to backhaul network and gives broadband wireless service to mobile stations. IEEE 802.16j standard which is an amendment to IEEE 802.16, introduces Multihop Relaying for increasing coverage and throughput. Deployment of relay stations, where the backbone network does not exist, is a cost effective solution. Two modes of operations are defined for relay station: transparent mode and non-transparent mode. Relays in transparent mode, are deployed for improving signal quality, so that mobile stations can use relay link for increasing throughput. In non-transparent mode, relays can send management packets, so that mobile stations, which are not in the direct reach of a base station, can connect to network through relay stations. In domain specific networks main data traffic is caused by the communication between subscribers in same region. In this thesis shortcut routing scheme is proposed as sending packets to destination directly through relay station for data traffic between two subscribers with a common relay. With shortcut routing, network throughput is increased by preventing links at higher layer in topology from becoming bottleneck. Moreover, by traversing fewer hops, latency decreases. We also propose traffic aware path selection method, where a path will more.

IEEE 802.16 is a point to multipoint broadband wireless access standard, designed from ground up for fast and reliable mobile networking. Several location-related MAC layer fields specified in the standard indicate that WiMAX networks can be convenient backbones for future positioning systems. Information encapsulated in MAC headers is especially important for single base station positioning systems which require fewer network resources than multiple reference station location systems, but need more location-related input data. In this thesis, an algorithm for positioning mobile stations in a single base station network is presented to investigate location capability of WiMAX systems. The algorithm makes use of fingerprinting to create a training database and seeks to find locations of mobile stations by tracking them according to their signal parameters. Experimental results give an idea about how a single base station positioning system performs in the absence of sufficient location-related data, and suggest that better results can be obtained if MAC headers specified in IEEE 802.16 standard can be accessed.

Novel compact antenna designs for WiMAX (Worldwide interoperability for microwave access) operation in the mobile phone are presented in this thesis. In the first design, the antenna is integrated at one corner of system circuit board of the mobile phone and consists of two radiating portions; the monopole slot is formed by integrating the two portions. In the second design, two different antenna structures are used to achieve all WiMAX operating bands. Finally, in the third design, the chip antenna comprises a resonant monopole patch, a resonant shorter slot and a matching longer slot. The latter two slots are embedded within the monopole patch to achieve a compact integration. Detailed antenna designs and experimental results are presented and discussed.

On a market of free competition, when consumers select their telecommunication service provider, they will not only consider basic elements such as the installation fee, call rate, and telecommunication reliability but also whether the provider can furnish the desired customer service, which is especially important. For most consumers, an essential part of customer service is the payment service. Due to the fact that there is not much difference in the technology, communication facilities and the type of business provided by different companies in the telecommunication industry, billing system and related customer services accordingly become the key differential factor and play a indispensable role in the decision-making process of customers. Moreover, as far as the operation, management, and strategy are concerned, billing system is the key backup for telecommunication enterprises. Establishing a billing system meeting the requirement of an enterprise that can provide the desired customer services hence becomes a priority for large telecommunication companies wishing to gain the upper hand in competition. This research uses the software architecture concept to develop a set of description language for the WiMAX billing management system based on which the architecture-oriented WiMAX billing management system model, abbreviated as AOWBMSM, is formulated. AOWBMSM is an integral model of the WiMAX billing management system framework which adopts the structure behavior coalescence, abbreviated as SBC, approach. It can clearly and completely describe the WiMAX billing management system and hopefully can serve as a model with more reference value when enterprises are planning, analyzing, and designing their payment system.

WiMAX與3G是目前無線行動寬頻接取技術中，最有可能成為主流的兩種技術。3G進入市場的時間較早，優勢在於具備強大的移動性。但是與其配合的終端裝置大部分為無法執行太多任務的手機，因此在內容服務上並無法獲得良好的發展。另一方面，WiMAX以低成本、高傳輸速率、良好行動性為訴求，緊隨著WiFi的成功之後開始進入無線行動寬頻接取服務的市場。不過一般預期WiMAX早期的應用終端裝置以行動性不高的筆記型電腦為主，並逐漸往高行動性的手持裝置發展。本研究主要探討的主題在於，當WiMAX以新進者的形態進入3G已存在的無線行動寬頻市場時，這兩種相近的技術產生何種競爭與合作的關係。 本研究以產業資料及文獻回顧整合出的探討角度來探討WiMAX與3G可能的競合狀況。另外，本研究也採取專家意見法來獲得實務業界對WiMAX與3G競合狀況的看法，以補足僅以文獻與次級資料探討本研究主題的不足。本研究檢視與整理WiMAX與3G在技術上的表現後發現，WiMAX在技術上的表現在目前及未來的兩三年之間都優於3G的相關技術標準。而藉由系統產品的特性與網路外部性、標準競爭與數位匯流的角度來探討WiMAX與3G可能的市場表現特性與競爭合作關係後也發現，WiMAX相對於3G具有低成本的特性，但3G在安裝基礎、線路普及率、全球工作頻段的一致性上，則有WiMAX未能具備的絕對優勢。因此何者能成為市場上主流的無線行動寬頻接取技術，尚未能有明確的定論。 WiMAX與3G在一開始的關係是合作大於競爭，而隨著WiMAX進入市場的時間越長，兩者之間的關係也由合作慢慢轉為競爭。而主要影響WiMAX與3G競爭關係的關鍵變數有四個：政府對WiMAX發展的態度、快速建立消費者期望的能力及對終端裝置產品發展趨勢的掌握、無線行動寬頻服務需求的成長狀況。WiMAX與3G 何者能確實影響或掌握四項關鍵變數的變化，將能真正成為市場上無線行動寬頻接取技術的主流。 / Among all kinds of broadband wireless access technologies, WiMAX and 3G are the 2 most potential candidates to dominate the future broadband mobile date service marrket. On the one hand, 3G moves into the market earlier and has the advantage of high mobility and popular existed 2G, 2.5G subscribers as bases. However, the content service on 3G doesn’t get prospered due to the complemental terminal devices comprise mostly handheld phones which aren’t capable of performing complicated tasks. On the other hand, WiMAX tries to follow the success of WiFi, and positions as the low cost, high data rate, and metropolitan area mobile solution in the broadband mobile data service. The most possible complemental terminal devices for WiMAX in early stage are notebooks which don’t provide high mobility, and will gradually migrate to handsets with high mobility then. This study tried to figure out the competition and cooperation between WiMAX and 3G when WiMAX as a new comer move into the broadband mobile data service market with 3G already existed in it. This study discussed the possible competition and cooperation between WiMAX and 3G based on the industrial data and related literatures. Professions interviews were also included to supplement with the practical viewpoint of telecom operators. From the technical perspective, WiMAX has better performance and will lead 3G for next 2 to 3 years. From the perspective of systematic product, network externalities, standard competition, and digital convergence, WiMAX surpasses 3G in lower cost, and 3G is superior to WiMAX in larger installed base, potential subscribers and consistent international radio band. As a result, there is no clear conclusion can be made which of WiMAX and 3G can dominate the broadband mobie datea service market in the future. WiMAX will cooperate more than compete with 3G in telecom operators at its early movement into the market. As the time pass by, WiMAX will compete more than cooperate with 3G. The four critical variables to influence the competition between WiMAX and 3G are: the government attitude to WiMAX development, the ability to establish the consumers’ expectation, response to mobile terminal devices trend, and the growth of the wireless mobile broadband demand. Either WiMAX or 3G has the potential to be the mainstream in the wireless mobile broadband market provided that which can influence or respond to the four variables above better.

Στα πλαίσια αυτής της διπλωματικής εργασίας μελετήσαμε μεθόδους κωδικοποίησης με χρήση πινάκων ισοτιμίας μεγάλων διαστάσεων που έχουν χρησιμοποιηθεί και εφαρμοσθεί μέχρι τώρα σε προηγούμενες μελέτες. Επιλέξαμε τη σχεδίαση ενός αποκωδικοποιητή, που στηρίζεται στο WiMAX – 802.16e ΙΕΕΕ πρότυπο μετάδοσης και συγκεκριμένα με χρήση πομπού και δέκτη με περισσότερες από μία κεραίες. Παρουσιάζουμε, λοιπόν τη θεωρία που συσχετίζεται με το θέμα αυτό τόσο από την πλευρά της κωδικοποίησης όσο κι από την πλευρά της ασύρματης ΜΙΜΟ μετάδοσης και το πρότυπο WiMAX. Αναλύουμε κάθε τμήμα του συστήματός που προσομοιώνουμε και παραθέτουμε τα αποτελέσματα της προσομοίωσης. / -

We are very thirsty in terms of everything to fulfil our needs in a sophisticated way, and this leads me choose the so called master thesis titled “Multihop Concept in Cellular Systems”. This thesis introduces an approach towards the integration of relaying or multihop scheme in the next generation of cellular networks. In a multihop cellular architecture, the users send their data to the base station via relay station or with direct communication to the base station. These relay stations can either be the nomadic, fixed at specific location or users’ mobile station (i.e. mobile relay station). The main objective of this paper is to compare the difference between the relaying network architecture with different channel bandwidth as well as their performance gain. For this we integrate the relay station into conventional cellular networks using IEEE 802.16j (One of the standard introduced relay station concept in WiMAX) OFDMA (Orthogonal Frequency Division Multiple Access is a transmission technique that is based on many orthogonal subchannels (set of carriers) that transmits simultaneously). The results show that under certain conditions the throughput and coverage of the system has been increased with the introduction of the relay station in to cellular base station zone.

In recent years, the ever-increasing environmental friendliness concern has made energy efficiency in telecom networks as an important theme in their operations. Meanwhile, mission-critical (MC) services and systems (such as healthcare, police, and firefighting) have been acquiring special attention from telecom designers and operators. The currently deployed MC network technologies are indigent in terms of bandwidth capacity, and thus they are not able to support the emerging MC multimedia applications. Therefore in this thesis, we first explore the possibility of provisioning the MC services over the integration of fiber-wireless (FiWi) technologies, which has been considered as a promising candidate for the deployment of high-speed and mobile broadband access networks. We then investigate the energy efficiency problem in the FiWi integration, which consists of WiMAX in the wireless plane, and of Ethernet Passive Optical Network (EPON) - the most popular variant of the next-generation PON (NG-PON) technology, in the optical plane. In WiMAX, the energy saving protocol has been extensively investigated and standardized. Conversely, it has been recently studied in NG-PON, which currently consumes the least power among all the high-speed access networks. However, NG-PON has notably matured in the past few years and is envisioned to massively evolve in the near future. This trend will increase the power requirements of NG-PON and make it no longer coveted. Therefore we address the energy efficiency problem in NG-PON. For each of our contributions, we conduct extensive simulations to demonstrate the effectiveness and advantages of the proposed solutions.