Economically sustainable public security and emergency network exploiting a broadband communications satellite

The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with little or no terrestrial last-mile telecommunications infrastructure for delivery of satellite solutions, applications and services. As such, the research provides a case study of a Nigerian Public Safety Security Communications Pilot project deployed in regions of the African continent with inadequate terrestrial last mile infrastructure and thus requiring a robust regional Communications Satellite complemented with variants of terrestrial wireless technologies to bridge the digital hiatus as a short and medium term measure apart from other strategic needs. The research not only addresses the pivotal role of a secured integrated communications Public safety network for security agencies and emergency service organizations with its potential to foster efficient information symmetry amongst their operations including during emergency and crisis management in a timely manner but demonstrates a working model of how analogue spectrum meant for Push-to-Talk (PTT) services can be re-farmed and digitalized as a “dedicated” broadband-based public communications system. The network’s sustainability can be secured by using excess capacity for the strategic commercial telecommunication needs of the state and its citizens. Utilization of scarce spectrum has been deployed for Nigeria’s Cashless policy pilot project for financial and digital inclusion. This effectively drives the universal access goals, without exclusivity, in a continent, which still remains the least wired in the world

Performance measurements and analysis of the existing wireless communication technology in Iraq.

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityIraq may be considered as the largest wireless market in the Gulf region. A key driving factor in the market of wireless communication, it has seen enormous growth in the mobile phone market over the last five years leading to almost 24 million subscribers in 2011. Moreover, there are several technologies and services working in Iraq; three GSM Operators, three CDMA national operators and three CDMA provinces operators. The recent growth in the mobile phone market is based on the Global System for Mobile (GSM) communications and Code Division Multiple Access (CDMA) standards creating the next-generation wireless technologies in the Iraqi Wireless Communication market. One of the essential issues of this research is to investigate the performance of the decreased Quality Of Service (QoS) caused by interferences in the services on GSM/CDMA operators in Iraq. Many issues should be studied and taken into consideration, such as; does the Multi-Coalition Forces cause the interferences, jamming, higher rate of calls drop and false ringing; or are they caused by bad design and planning? Do we need to optimise our network due to the large number of users? All these factors are investigated and the measurements of most service providers and government agencies will be gathered. A detailed analysis was included from the providers with measurements of performance and the reasons for the deterioration of wireless services. The novel contributions of this thesis is the extensive radio measurement campaign over the three mobile an CDMA operator networks and the analysis and recommendations that were drawn to suggest the best approach to improve the QoS of Wireless communication technologies. Awareness of actual reasons behind the deterioration of services will be raised to the Iraqi Government, CMC and the wireless service providers

Concurrent Multi-Band Envelope Tracking Power Amplifiers for Emerging Wireless Communications

Emerging wireless communication is shifting toward data-centric broadband services, resulting in employment of sophisticated and spectrum efficient modulation and access techniques. This yields communication signals with large peak-to-average power ratios (PAPR) and stringent linearity requirements. For example, future wireless communication standard, such as long term evolution advanced (LTE-A) require adoption of carrier aggregation techniques to improve their effective modulation bandwidth. The carrier aggregation technique for LTE-A incorporates multiple carriers over a wide frequency range to create a wider bandwidth of up to 100MHz. This will require future power amplifiers (PAs) and transmitters to efficiently amplify concurrent multi-band signals with large PAPR, while maintaining good linearity. Different back-off efficiency enhancement techniques are available, such as envelope tracking (ET) and Doherty. ET has gained a lot of attention recently as it can be applied to both base station and mobile transmitters. Unfortunately, few publications have investigated concurrent multi-band amplification using ET PAs, mainly due to the limited bandwidth of the envelope amplifier. In this thesis, a novel approach to enable concurrent amplification of multi-band signals using a single ET PA will be presented. This thesis begins by studying the sources of nonlinearities in single-band and dual-band PAs. Based on the analysis, a design methodology is proposed to reduce the sources of memory effects in single-band and dual-band PAs from the circuit design stage and improve their linearizability. Using the proposed design methodology, a 45W GaN PA was designed. The PA was linearized using easy to implement, memoryless digital pre-distortion (DPD) with 8 and 28 coefficients when driven with single-band and dual-band signals, respectively. This analysis and design methodology will enable the design of PAs with reduced memory effects, which can be linearized using simple, power efficient linearization techniques, such as lookup table or memoryless polynomial DPD. Note that the power dissipation of the linearization engine becomes crucial as we move toward smaller base station cells, such as femto- and pico-cells, where complicated DPD models cannot be implemented due to their significant power overhead. This analysis is also very important when implementing a multi-band ET PA system, where the sources of memory effects in the PA itself are minimized through the proposed design methodology. Next, the principle of concurrent dual-band ET operation using the low frequency component (LFC) of the envelope of the dual-band signal is presented. The proposed dual-band ET PA modulates the drain voltage of the PA using the LFC of the envelope of the dual-band signal. This will enable concurrent dual-band operation of the ET PA without posing extra bandwidth requirements on the envelope amplifier. A detailed efficiency and linearity analysis of the dual-band ET PA is also presented. Furthermore, a new dual-band DPD model with supply dependency is proposed in this thesis, capable of capturing and compensating for the sources of distortion in the dual-band ET PA. To the best of our knowledge, concurrent dual-band operation of ET PAs using the LFC of the envelope of the dual-band signal is presented for the first time in the literature. The proposed dual-band ET operation is validated using the measurement results of two GaN ET PA prototypes. Lastly, the principle of concurrent dual-band ET operation is extended to multi-band signals using the LFC of the envelope of the multi-band signal. The proposed multi-band ET operation is validated using the measurement results of a tri-band ET PA. To the best of our knowledge, this is the first reported tri-band ET PA in literature. The tri-band ET PA is linearized using a new tri-band DPD model with supply dependency

Passive intermodulation tester characteristics

Abstract. Passive intermodulation (PIM) is a severe issue for base transceiver stations. It can cause issues to the receiver of the device or to nearby devices if power levels are high enough. In the past, there have been many studies on the PIM, mostly concerning on modelling and mitigation of PIM. In this thesis, 3rd and 5th order forward PIM levels are measured and analysed from base station filters to determine if they are good enough for receiving of low-level signals. Also, used PIM test setup is simulated with modified component parameters for finding output third order intercept point (OIP3) threshold values of each component for which the setup still provides accurate enough results. Also, noise level calculations and cost estimation of typical PIM test setup is presented. PIM products were measured with accurate test setups that had residual PIM levels clearly below measured levels. As PIM performance often varies with time all measurements were repeated several times. The best unit out of all 10 measured devices under test (DUTs) had 100 % pass rate and less than 2.5 dB standard deviation. Results were also more than 8.5 dB over the limit in average. All the results were calculated from all measurement samples of DUTs. There were 4–16 of measurements per DUT. The worst unit had 25% pass rate and PIM results that were below limit in average. PIM results suggest that high standard deviation is linked to failed results, usually. Two additional DUTs was tested for finding if the source was electro-thermal nonlinearity. The results suggest that it might have been the source, but due to low quantity of measurements, waterproof conclusion can’t be made. There are many limiting factors in testing of PIM. First of all, the test results must be clearly above noise floor in order to see the real PIM products. Also, the test setup must have its residual intermodulation at least 10 dB below the measured PIM of DUT. Then, the measured results are considered to be accurate enough. That’s why the components of the setup have to be low-PIM. For these reasons, test setup simulations were done with AWR simulation tool in order to find the threshold values on which the setup still provides reliable test results for each test setup components. It was found out that the combiner should have the highest OIP3 value, of at least 61.3 dBm when ≈ 40 dB notch filter was used before DUT at the measured 3rd order PIM frequency. Without notch, OIP3 should be at least 73.7 dBm. Therefore, notch filter lowered the need of OIP3 by 12.4 dB. Signal generators, power amplifiers and circulators of the setup were limited by their 1 dB compression point. As a conclusion, this thesis work was successful since the limitations of the setup were found by simulations and calculations. Also, testing and analyzing of PIM products was performed successfully with low residual levels. The theory, calculations and simulations presented in this thesis can be used in acquisition of PIM test setup components. Also, the simulation model can be modified for simulating the PIM impact of any components in the test setup.Passiivisen keskinäismodulaatiotesterin piirteet. Tiivistelmä. Passiivinen keskinäismodulaatio (PIM) on vakava häiriö tukiasemille. Kun signaalien teho on tarpeeksi suuri, voi PIM aiheuttaa suuria ongelmia laitteen vastaanottamiskykyyn tai muihin lähellä oleviin laitteisiin. PIM:n mallinnusta ja heikennystä on tutkittu paljon menneisyydessä. Tässä diplomityössä 3:n ja 5:n asteen suoraan etenevän (eng. forward) PIM:n tasoja mitataan ja analysoidaan tukiasemien suodattimista, jotta voidaan päättää onko ne hyviä pienitehoisten signaalien vastaanottamiseen. Lisäksi käytettyä PIM-testijärjestelmää simuloidaan muuntamalla testijärjestelmän komponenttien parametrejä siten, että löydettäisiin jokaisen komponentin kolmannen asteen leikkauspisteen (OIP3) raja-arvot, jolla testijärjestelmä toimii taaten tarpeeksi tarkkoja tuloksia. Tavanomaisen PIM-testijärjeslmän kohinatason laskuja ja kustannusarvio on myös esitetty. PIM-tuotokset mitattiin tarkoilla testijärjestelmillä, joiden residuaaliset PIM-tasot olivat selvästi alle tutkittavasta laitteesta (DUT) mitattavia tasoja. Parhaalla yksiköllä 10:stä mitatusta oli 100 %:n läpäisytaso sekä alle 2,5 dB:n keskihajonta. Lisäksi, tulokset olivat keskimäärin 8,5 dB parempia kuin läpäisyraja. Kaikki tulokset on laskettu DUT:en kaikista mittausnäytteestä, joita oli 4–16 per DUT. Huonoimalla yksikkö oli 25 %:n läpäisytaso ja sen tulokset olivat keskimäärin alle läpäisyrajan. PIM-tulokset viittaavat siihen, että suuri keskihajonta on yleensä yhteydessä huonoihin tuloksiin. Kaksi ylimääräistä yksikköä testattiin, jotta tiedettäisiin olisiko PIM:n lähteenä sähkö-terminen epälineaarisuus. Tulokset viittaavat, että se voisi olla PIM:n lähde, mutta pienestä testimäärästä johtuen vedenpitävää johtopäätöstä ei voida tehdä. PIM:n testauksessa on monia rajoittavia tekijöitä. Ensinnäkin, testitulosten pitää olla selvästi yli kohinatason, jotta ne erottuvat nähtäviksi. Myös testijärjestelmän residuaalisen keskinäismodulaatio pitää olla vähintään 10 dB:ä matalemmalla tasolla kuin testattavan yksikön PIM. Siten mitatut tulokset mielletään tarpeeksi tarkoiksi. Sen takia testijärjestelmän osien pitää olla pienitasoisia PIM-teholtaan. Näiden syiden takia, testijärjestelmän simulointeja tehtiin AWR-simulointityökalun avulla, jotta löydettäisiin raja-arvot mittajärjestelmän eri osille, millä mittajärjestelmä tuottaa luotettavia tuloksia. Selvitettiin, että kaikista osista yhdyssuodattimella (eng. combiner) pitäisi olla suurin kolmannen asteen leikkauspiste (OIP3), vähintään 61.3 dB noin 40 dB:n kaistanestosuodattimen, joka tulee ennen DUT:a mitattavalle PIM-taajuudelle, kanssa ja vähintään 73.7 dB ilman kaistanestosuodatinta. Täten suodatin laski OIP3:n tarvetta 12.4 dB. 1 dB kompressiopisteet rajoittivat OIP3-raja-arvoja signaaligeneraattoreilla, tehovahvistimilla ja sirkulaattoreilla. Kaikkiaan työ oli onnistunut, sillä testijärjestelmän rajoitukset löydettiin simulointien ja laskutoimitusten avulla. Lisäksi mittaukset ja PIM-tulosten analysointi tehtiin onnistuneesti pienillä residuaalisilla tasoilla. Tämän diplomityön teoriaa, laskutoimituksia ja simulaatioita voidaan käyttää PIM-testijärjestelmän komponenttien hankintaan. Lisäksi, simulaatiomallia voidaan muokata siten, että minkä tahansa komponentin vaikutusta PIM-häiriöihin voidaan simuloida sen avulla

Optimization of the methodology of configuration of mobile communication networks

The mobile communication network has been growing quickly, and the mobile network maintenance is becoming more complex, in performance, network coverage, energy, time consuming and expensive. The telecommunication service provider and mobile network telecommunication operator worries to what is the better methodology to optimizing a mobile network configuration and to improve the most efficient operation and functionality, to increase a superior performance in technical aspect (Create, and integrate new network planning in hardware and software level), economic aspect (cost reduction in maintenance) and environmental aspect (use of renewable energy through solar panels or wind power system). The work developed in this dissertation aims to propose an optimization of methodology of configuration of mobile communication network and build an automated configuration system in different technology (GSM, UMTS and LTE) to provide a good quality and improvement in its architecture to meet the requirement for a large number of services or application through distinct means transmission and using technology appropriate with a new generation of hardware to reach certain area in a Base Station Transmition (BTS) and a Radio Network Controller (RNC) that permit configure and integrated hardware and software issues in distinct networks technology (GSM, UMTS and LTE).A rede de comunicação móvel tem crescido rapidamente e ficando cada vez mais complexa, sendo cada vez mais complicado melhorar o desempenho, a cobertura, a eficiência energética e ao mesmo tempo aumentar o numero de utilizadores e serviços. O provedor de serviços de telecomunicações e a operadora de rede móvel têm de se preocupar em optimizar de forma a garantir a melhor configuração de rede móvel tendo em vista melhorar a operação e funcionalidade, a fim de esta ser mais eficiente, no seu desempenho. Relativamente aos aspectos técnicos (Criar novo planeamento e integrar a uma rede ao nível hardware e de software), aspecto econômico (redução de custo na manutenção) e aspecto ambiental (uso de energia renovável, quer através de painéis solares como de sistemas eólicos). O trabalho desenvolvido nesta dissertação visa propor uma otimização da metodologia de configuração das redes de comunicação móveis e construir um sistema de configuração automatizado em diferentes tecnologias (GSM, UMTS e LTE), para garantir os mais altos padrões de qualidade e atender a exigência de um grande número de serviços ou aplicações através de diferentes meios de transmissão e uso de tecnologia apropriada com uma nova geração de hardware para atingir determinada área em uma Estação de Transmissão de Base (BTS) e numa Rede de Controlador de Rádio (RNC) que permitem configurar e integrar diversos tipos de hardware e software em tecnologia de diferentes redes (GSM, UMTS e LTE)

Medida e análise de atividade espetral

Mestrado em Engenharia Electrónica e TelecomunicaçõesThe dissertation deals with measuring and analyzing spectrum occupancy of a GSM900 band, DCS1800 band and all UMTS bandwidth. A modelization for analog power and binary quantized power is given. In the case of analog power, histograms of the power distribution during one working day are presented. In the case of quantized power the two time statistics, the time period of opportunities distribution and the time between opportunities distribution are presented, described and modeled. The measurement setup is standing in line of sight with the base station. Also, in terms of maximum sensitivity the measurement setup is described and analyzed. Spectrum non occupancy in terms of total time for the GSM900 band and the DCS1800 band is given, for a working day.Nesta dissertação são feitas medidas e a análise de ocupação de espectro em uma banda de GSM900, uma banda de DCS1800 e toda a largura de banda do UMTS. É apresentada uma modelização para potência analógica e para a potência binária quantizada. No caso da potência analógica são apresentados histogramas da distribuição de potência ao longo de um dia útil. No caso da potência quantizada as duas estatísticas, distribuição do período de tempo de oportunidades e distribuição do tempo entre oportunidades, são apresentadas, descritas e modeladas. O setup de medida encontra-se em linha de vista com a estação base. O setup é descrito e analisado em termos de máxima sensibilidade. A desocupação de espectro em termos de tempo total para a banda de GSM900 e para a banda DCS1800 é fornecida, para um dia de útil

The effects of part commonality on product development lead time

Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, 2005.Includes bibliographical references (p. 131-132).Nortel Networks, a leading global supplier of telecommunications equipment, is engaged in an increasingly competitive global market place. Within this market, Nortel Networks is positioning itself as the leader of global network transformation. The vision of the new transformed network is one in which disparate network elements are converged onto single architectural platforms serving the Client, Wireless Access, Network Services, Multi-services Packet, VoIP, Multi-services Optical and Element Management aspects of the newly transformed network architecture. This paper focuses specifically on the hardware development process associated with the CDMA wireless access element referred to as a base transceiver station (BTS) in the transformed network. The effect of part commonality on product development lead times are investigated at four levels of integration: common part (ASIC), common assembly (circuit pack), common field replaceable unit (module) and finally the common platform (BTS). At increasing levels of integration, the use of common parts leads to longer product development lead times. This observation is examined using two methodologies. The first methodology utilizes the three lenses framework focusing primarily on the impacts of organizational structure on the product development process. An evaluation of the existing barriers preventing joint gains and acceptable compromises to be achieved amongst share holders in joint development programs is discussed. Methods by which to minimize the impact of organizational structure on common product development lead time are given and comparisons are made with alternate organizational models from within the telecommunications industry. The second methodology employed utilizes task(cont.) design structure matrices (DSM) to analyze the implication of part commonality on product development lead times for projects structured in accordance with the Nortel Networks Life Cycle Management model. Effects modeled include stochastic durations, probabilistic iterations, learning effects, resource constraints, parallel tasks and overlapping tasks. An evaluation of the results indicates an increased sensitivity to extended product development lead times associated with probabilistic iterations. This is shown to be particularly evident during the requirements definition phase in which multiple stakeholder requirements must be captured comprehensively. This sensitivity is amplified by the fact that product verification takes place in multiple labs each exercising the equipment in unique and un-accounted for configurations. Based on the above analysis, a framework to ascertain the optimum level of commonality to pursue on a given product is given.by Nicholas Svensson.S.M