The component that generates the frequency of the radio waves transmitted by a radar is generally built around a quartz crystal oscillator. When this component is exposed to mechanical vibrations, such as acceleration or rotation in different directions, phase noise occurs. That is due to the piezoelectric effect of quartz crystals, which eventually degrades the performance of a radar. High frequency noise are compensated for using mechanical dampers. However, the low frequency noise remains and requires a digital solution. To solve this, a theoretical compensation model for the quartz crystal has been designed. It was possible to measure the noise generated by the quartz crystal by utilising an accelerometer, perform simulations and calculations. With the help of these different tools, it was possible to theoretically calculate and reduce the phase noise by 30-40%. All the results that has been obtained are theoretical results and nothing has yet been implemented in any radar system.

I examensarbetet undersöks användningen av VR som komplement i projekteringsfasen. Arbetet syftar till att skapa en smidig inkörningsfas, testa tekniken på ett verkligt projekt samt att hitta ett koncept kring utrustning, mjukvaror och hårdvaror som är lämpligt för BSV Arkitekter & Ingenjörer samt liknande företag. Problemet som arbetet grundar sig i är att få antal företag använder VR eftersom branschen är konservativ men också för att tekniken är relativt ny. I arbetet har metoder som intervjuer, litteratursökning och tester använts. I resultatet finns personliga intervjuer, teoretisk data, tester av utrustning och test av VR på ett verkligt projekt. Teknikens tillämpning på ett verkligt projekt gjorde undersökningen unik och givande för företag som är intresserade av att testa tekniken. Nyckelord: Virtual Reality (VR), Projekteringsfas, Kommunikation, Byggbranschen

Zhang Jun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 82-92). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Multipath Fading Channels --- p.1 / Chapter 1.2 --- Diversity --- p.3 / Chapter 1.3 --- Outline of the Thesis --- p.6 / Chapter 2 --- Background and Related Work --- p.8 / Chapter 2.1 --- Cooperative Diversity --- p.8 / Chapter 2.1.1 --- User Cooperation --- p.9 / Chapter 2.1.2 --- Cooperative Diversity --- p.10 / Chapter 2.1.3 --- Coded Cooperation --- p.12 / Chapter 2.2 --- Information-Theoretic Studies --- p.13 / Chapter 2.3 --- Multihop Cellular Networks --- p.15 / Chapter 2.3.1 --- MCN: Multihop Cellular Network --- p.15 / Chapter 2.3.2 --- iCAR: Integrated Cellular and Ad Hoc Relaying Systems --- p.17 / Chapter 2.3.3 --- UCAN: Unified Cellular and Ad Hoc Network Architecture --- p.17 / Chapter 2.4 --- Wireless Ad Hoc Networks --- p.18 / Chapter 2.5 --- Space-Time Processing --- p.20 / Chapter 3 --- Single-Source Multiple-Relay Cooperation System --- p.23 / Chapter 3.1 --- System Model --- p.23 / Chapter 3.2 --- Fixed Decode-and-Forward Cooperation System --- p.26 / Chapter 3.2.1 --- BER for system with errors at the relay --- p.28 / Chapter 3.2.2 --- General BER formula for single-source nr-relay cooperation system --- p.30 / Chapter 3.2.3 --- Discussion of Interuser Channels --- p.31 / Chapter 3.3 --- Relay Selection Protocol --- p.33 / Chapter 3.3.1 --- Transmission Protocol --- p.34 / Chapter 3.3.2 --- BER Analysis for Relay Selection Protocol --- p.34 / Chapter 4 --- Multiple-Source Multiple-Relay Cooperation System --- p.40 / Chapter 4.1 --- Transmission Protocol --- p.41 / Chapter 4.2 --- Fixed Cooperative Coding System --- p.43 / Chapter 4.2.1 --- Performance Analysis --- p.43 / Chapter 4.2.2 --- Numerical Results and Discussion --- p.48 / Chapter 4.3 --- Adaptive Cooperative Coding --- p.49 / Chapter 4.3.1 --- Performance Analysis of Adaptive Cooperative Coding System --- p.50 / Chapter 4.3.2 --- Analysis of p2(2) --- p.52 / Chapter 4.3.3 --- Numerical Results and Discussion --- p.53 / Chapter 5 --- Cooperative Multihop Transmission --- p.56 / Chapter 5.1 --- System Model --- p.57 / Chapter 5.1.1 --- Conventional Multihop Transmission --- p.58 / Chapter 5.1.2 --- Cooperative Multihop Transmission --- p.59 / Chapter 5.2 --- Performance Evaluation --- p.59 / Chapter 5.2.1 --- Conventional Multihop Transmission --- p.60 / Chapter 5.2.2 --- Cooperative Multihop Transmission --- p.60 / Chapter 5.2.3 --- Numerical Results --- p.64 / Chapter 5.3 --- Discussion --- p.64 / Chapter 5.3.1 --- Cooperative Range --- p.64 / Chapter 5.3.2 --- Relay Node Distribution --- p.67 / Chapter 5.3.3 --- Power Allocation and Distance Distribution (2-hop Case) --- p.68 / Chapter 5.4 --- Cooperation in General Wireless Ad Hoc Networks --- p.70 / Chapter 5.4.1 --- Cooperation Using Linear Network Codes --- p.71 / Chapter 5.4.2 --- Single-Source Single-Destination Systems --- p.74 / Chapter 5.4.3 --- Multiple-Source Single-Destination Systems --- p.75 / Chapter 6 --- Conclusion --- p.80 / Bibliography --- p.82 / Chapter A --- Proof of Proposition 1-4 --- p.93 / Chapter A.1 --- Proof of Proposition 1 --- p.93 / Chapter A.2 --- Proof of Proposition 2 --- p.95 / Chapter A.3 --- Proof of Proposition 3 --- p.95 / Chapter A.4 --- Proof of Proposition 4 --- p.96

In the first part of this thesis, we focus on Drive-thru Internet systems where access points (AP) are placed on roadsides and vehicles passing through the coverage range of the APs can download data from them. The amount of data downloaded by an individual user is affected not only by the scheduling algorithms, but also by the user dynamics, i.e. the movement of the vehicles which impacts the amount of time the vehicle spends in the AP's coverage range, as well as the number of contending vehicles for the AP's resources. We have developed practical analytical models with tractable solutions to characterize the data communication performance of a vehicle in a Drive-thru Internet system. A distinctive aspect of our models is that they combined both vehicular traffic theory and wireless network/protocol properties to investigate the effects of various system parameters on a drive-thru vehicle's data communication performance. / In the second part of this thesis, we examine resource sharing in wireless sensor networks in terms of the node access to the wireless medium. We propose an energy-efficient TDMA-based MAC protocol that significantly reduces energy consumption in the network, while efficiently handling network traffic load variations and optimizing channel utilization through a timeslots stealing mechanism and timeslots reassignment procedure. We have analytically derived the average delay performance of our MAC protocol, with and without the timeslots stealing feature. Our delay model, validated via simulations, shows that the timeslots stealing feature can substantially improve the protocol throughput in situations with varying and asymmetric traffic patterns. Simulation results show that the timeslots reassignment procedure is efficient in handling the longer timescale changes in the traffic load, while the timeslots stealing mechanism is better in handling the shorter timescale changes in the traffic patterns. / In wireless networks, the efficient sharing of scarce wireless spectral resources is important in order to provide guaranteed Quality-of-Service (QoS) to the wireless users. The effectiveness of resource sharing schemes in wireless networks are often heavily influenced by different aspects of the system behavior, such as user mobility, traffic dynamics and practical realization constraints. In this thesis, using analytical modeling and empirical measurement techniques, we investigate the impact of these system behaviors on the performance of resource sharing in wireless networks. In particular, we investigate the dynamic sharing of an access point's bandwidth resources among moving vehicles in a vehicular network, the adaptive sharing of the medium access resources among nodes with different and varying traffic loads in a wireless sensor network, and the practical implementation of network resources sharing among users and applications with different QoS requirements in 3G wireless networks. / The third part of this thesis focuses on our empirical investigations into the performance of practical implementation of resource sharing schemes in 3G wireless networks. We have investigated the performance of multiple commercial 3G networks in Hong Kong, in terms of their ability to provide service guarantees to different traffic classes as well as the fairness of the radio-link scheduler in allocating the bandwidth resources to multiple data calls in a saturated network. We have also investigated the data throughput, latency, video and voice calls handling capacities of the 3G networks under saturated network conditions. Our findings point to the diverse nature of the network resources allocation mechanisms and the call admission control policies adopted by different operators. Our results also show that the 3G network operators seem to have extensively customized their network configurations in a cell-by-cell manner according to the individual site's local demographics, projected traffic demand and the target coverage area of the cell. As such, the cell capacity varies widely not only across different operators but also across different measurement sites of the same operator. / by Tan, Wee Lum. / Adviser: Wing Cheong Lau. / Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 129-138). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

First, we give the first formal study on stream control scheduling in wireless mesh networks with Multi-Input-Multi-Output (MIMO) antennas and study how much it can improve network capacity. We derive the upper bound of the optimal network capacity gain of stream control. We also propose an efficient stream control scheduling algorithm, GreedySC. Simulations show the network capacity of GreedySC is much larger than that of a previously proposed stream control scheduling algorithm, SCMA. / Second, we consider leveraging transmission power to improve the network capacity of wireless mesh networks. It is well-known that power control can improve network capacity significantly. However, recent works show conflicting results: network capacity may increase or decrease with higher transmission power under different scenarios. In this work, we give the first systematic study on this paradox. We prove that the the optimal network capacity is a non-decreasing function of higher transmission power. We also derive the upper bound of the optimal network capacity gain of power control. Finally, we give the reasons why network capacity may increase or decrease with higher transmission power in practice. Simulations verify our arguments. / The next generation wireless networks target at providing better quality of service for ubiquitous network access than nowaday wireless networks. Various technologies from the physical layer to the transport layer are proposed to realize this goal. A fundamental question is how to characterize the impact of a new technology on the performance of wireless networks, e.g., network capacity, backlog and delay. We propose to apply optimization theory for the network capacity characterization and apply stochastic network calculus for the backlog and delay characterization. However, the detailed characterization procedure depends on different problems. In this thesis, we first formally define network capacity, the (optimal) network capacity gain of a new technology, backlog and delay. Then we carry out systematic characterizations on the following three important issues in designing the next generation wireless networks. / Third, we take the first step to apply stochastic network calculus for the backlog and delay analysis of 802.11 wireless local networks. We prove the general stability condition of deriving stable backlog and delay for a wireless node. From this, we derive the specific stability condition of an 802.11 wireless node. Then we derive the stochastic service curve of an 802.11 node. Based on the service curve, we derive the backlog and delay bounds of the node. Simulations verify our analysis. / Wang, Yue. / Adviser: John C. S. Lui. / Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 109-117). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Hui, Ka Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 123-126). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction / Motivation --- p.1 / Chapter 2 --- Literature Review --- p.6 / Chapter 2.1 --- Introduction --- p.6 / Chapter 2.2 --- The Capacity-Finding Problem --- p.6 / Chapter 2.3 --- Interference Models --- p.8 / Chapter 2.4 --- Considering Interference in the Capacity-Finding Problem with Perfect Scheduling --- p.9 / Chapter 2.4.1 --- Conflict Graph --- p.10 / Chapter 2.4.2 --- Independent Set Constraints --- p.11 / Chapter 2.4.3 --- Row Constraints --- p.11 / Chapter 2.4.4 --- Clique Constraints --- p.12 / Chapter 2.4.5 --- Using the physical model --- p.13 / Chapter 2.5 --- Considering Interference in the Capacity-Finding Problem with Random Access --- p.15 / Chapter 2.6 --- Chapter Summary --- p.17 / Chapter 3 --- Partial Interference - Basic Idea --- p.18 / Chapter 3.1 --- Introduction --- p.18 / Chapter 3.2 --- Deficiencies in Previous Models --- p.18 / Chapter 3.2.1 --- Multiple Interferers --- p.19 / Chapter 3.2.2 --- Non-binary Behavior of Interference --- p.19 / Chapter 3.2.3 --- Impractical Perfect Scheduling --- p.21 / Chapter 3.3 --- Refining the Relationship between Interference and Throughput Degradation --- p.21 / Chapter 3.4 --- Capacity Gain by Exploiting Partial Interference . --- p.23 / Chapter 3.5 --- Chapter Summary --- p.28 / Chapter 4 --- Partial Interference in 802.11 --- p.29 / Chapter 4.1 --- Introduction --- p.29 / Chapter 4.2 --- The 802.11 Model --- p.29 / Chapter 4.2.1 --- Assumptions --- p.30 / Chapter 4.2.2 --- Transmission Probability Calculation --- p.31 / Chapter 4.2.3 --- Packet Corruption Probability Calculation --- p.34 / Chapter 4.2.4 --- Loading Calculation --- p.35 / Chapter 4.2.5 --- Summary --- p.36 / Chapter 4.3 --- Some Analytical Results --- p.37 / Chapter 4.4 --- A TDM A/CDMA Analogy --- p.40 / Chapter 4.5 --- Admissible (Stability) Region --- p.42 / Chapter 4.6 --- Chapter Summary --- p.44 / Chapter 5 --- Partial Interference in Slotted ALOHA --- p.45 / Chapter 5.1 --- Introduction --- p.45 / Chapter 5.2 --- The Finite-Link Slotted ALOHA Model --- p.46 / Chapter 5.2.1 --- Assumptions --- p.46 / Chapter 5.2.2 --- Stability of Slotted ALOHA --- p.46 / Chapter 5.3 --- Stability Region of 2-Link Slotted ALOHA under Partial Interference --- p.47 / Chapter 5.4 --- Some Illustrations --- p.50 / Chapter 5.5 --- Generalization to the M-Link Case --- p.53 / Chapter 5.6 --- Chapter Summary --- p.58 / Chapter 6 --- FRASA --- p.59 / Chapter 6.1 --- Introduction --- p.59 / Chapter 6.2 --- The FRASA Model --- p.60 / Chapter 6.3 --- Validation of the FRASA Model --- p.66 / Chapter 6.3.1 --- Simulation Results --- p.66 / Chapter 6.3.2 --- Comparison to Previous Bounds --- p.72 / Chapter 6.4 --- Convex Hull Bound --- p.75 / Chapter 6.5 --- p-Convexity --- p.80 / Chapter 6.6 --- Supporting Hyperplane Bound --- p.86 / Chapter 6.7 --- Extension to Partial Interference --- p.89 / Chapter 6.7.1 --- FRASA under Partial Interference --- p.90 / Chapter 6.7.2 --- Convex Hull Bound --- p.93 / Chapter 6.7.3 --- p-Convexity --- p.97 / Chapter 6.7.4 --- Supporting Hyperplane Bound --- p.101 / Chapter 6.8 --- Chapter Summary --- p.102 / Chapter 7 --- Conclusion and Future Works --- p.110 / Chapter 7.1 --- Conclusion --- p.110 / Chapter 7.2 --- Future Works --- p.111 / Chapter A --- Proof of (4.13) in Chapter 4 --- p.113 / Bibliography --- p.123

Massive MIMO (multiple-input multiple-output) is considered as an heir of the multi-user MIMO technology and it has recently gained lots of attention from both academia and industry. By equipping base stations (BSs) with hundreds of antennas, this new technology can provide very large multiplexing gains by serving many users on the same time-frequency resources and thereby bring significant improvements in spectral efficiency (SE) and energy efficiency (EE) over the current wireless networks. The transmit power, pilot training, and spatial transmission resources need to be allocated properly to the users to achieve the highest possible performance. This is called resource allocation and can be formulated as design utility optimization problems. If the resource allocation in Massive MIMO is optimized, the technology can handle the exponential growth in both wireless data traffic and number of wireless devices, which cannot be done by the current cellular network technology. In this thesis, we focus on two resource allocation aspects in Massive MIMO: The first part of the thesis studies if power control and advanced coordinated multipoint (CoMP) techniques are able to bring substantial gains to multi-cell Massive MIMO systems compared to the systems without using CoMP. More specifically, we consider a network topology with no cell boundary where the BSs can collaborate to serve the users in the considered coverage area. We focus on a downlink (DL) scenario in which each BS transmits different data signals to each user. This scenario does not require phase synchronization between BSs and therefore has the same backhaul requirements as conventional Massive MIMO systems, where each user is preassigned to only one BS. The scenario where all BSs are phase synchronized to send the same data is also included for comparison. We solve a total transmit power minimization problem in order to observe how much power Massive MIMO BSs consume to provide the requested quality of service (QoS) of each user. A max-min fairness optimization is also solved to provide every user with the same maximum QoS regardless of the propagation conditions. The second part of the thesis considers a joint pilot design and uplink (UL) power control problem in multi-cell Massive MIMO. The main motivation for this work is that the pilot assignment and pilot power allocation is momentous in Massive MIMO since the BSs are supposed to construct linear detection and precoding vectors from the channel estimates. Pilot contamination between pilot-sharing users leads to more interference during data transmission. The pilot design is more difficult if the pilot signals are reused frequently in space, as in Massive MIMO, which leads to greater pilot contamination effects. Related works have only studied either the pilot assignment or the pilot power control, but not the joint optimization. Furthermore, the pilot assignment is usually formulated as a combinatorial problem leading to prohibitive computational complexity. Therefore, in the second part of this thesis, a new pilot design is proposed to overcome such challenges by treating the pilot signals as continuous optimization variables. We use those pilot signals to solve different max-min fairness optimization problems with either ideal hardware or hardware impairments.

Thesis (M.S.)--State University of New York at Binghamton, Electrical Engineering Dept., 2006. / Includes bibliographical references.

Power is a valuable resource. It is invaluable when for mobile devices. Mobile devices, due to their mobility cannot get a continuous source of power and derive their power from a battery contained in them. The main consumer of power in the mobile is its transmitter. With a limited power capacity of the batteries, it is always desirable that the transmit power of the mobile be minimized. The aim of this thesis is to introduce a new architecture to minimize this problem. It is called as "Stretchable Architectures". The stretched architecture involves an intermediary between the Mobile Station and the Base Station to carry the call between them. This type of connection is called a Stretched connection. We explain the energy efficiency of a Stretched Connection when compared to a Direct connection between the Mobile Station and Base Station. We investigate the factors affecting a Stretched connection and propose different Stretchable Architectures, suitable for different applications. The "Stretched Architecture" is analyzed for the three 3G standards: Multi-carrier Direct Spread CDMA (CDMA2000), Wideband CDMA (WCDMA) and Time Division-CDMA (TD-CDMA). / Graduation date: 2002

Dynamic DC offset is one of the biggest problems preventing the implementation of single chip receivers. This thesis presents a 2.4GHz downconversion mixer designed to work with adaptive DC offset cancellation for a fully integrated direct conversion receiver. Offset can be removed by dynamically changing the PFET load bias in a Gilbert Cell type mixer. A dual-loop algorithm, which was developed in separate work, controls a current-steering DAC that dynamically changes the PFET load bias of the mixer. The mixer has a gain of 8dB, an IIP3 of l7dBm, and a noise figure of 15dB. In addition a CMOS RF Front-End incorporating the offset cancellation mixer is presented that meets the specifications for Bluetooth. / Graduation date: 2001