Power control for WCDMA

This project tries to introduce itself in the physical implementations that make possible the denominated third generation mobile technology. As well as to know the technology kind that makes possible, for example, a video-call in real time. During this project, the different phases passed from the election of WCDMA like the access method for UMTS will appear. Its coexistence with previous network GSM will be analyzed, where the compatibility between systems has been one of the most important aspects in the development of WCDMA, the involved standardization organisms in the process, as well as the different protocols that make the mobile communications within a network UTRAN possible. Special emphasis during the study of the great contribution that has offered WCDMA with respect to the control of power of the existing signals will be made. The future lines that are considered in the present, and other comment that already are in their last phase of development in the field of the mobile technology. UMTS through WCDMA can be summarized like a revolution of the air interface accompanied by a revolution in the network of their architecture

Performance Enhancement of DS-UWB Short Range Communication System Using Equalization Techniques

UWB is a major research area in the field of wireless communication. The IEEE 802.15.3a has been assigned the job of standardizing it. It is being considered as a breakthrough technology capable enough to revolutionize short range wireless communication. Ultra wideband communication as its name implies has large absolute bandwidth greater than 500 MHz and operating frequency band is 3.1 GHz- 10.6GHz. It is a rapidly growing technology that plays a very promising role in modern age wireless communication. It finds application in various sectors, for example in medical application to observe the status of patient using wireless health monitoring of life sustaining systems. In vehicular technology it can be used for obstacle avoidance and fast data transmission, and in military application as radar for detection behind walls and other blockages. Since it is based on short pulse carrier less transmission so hardware implementation becomes less complex and cheap. Thesis work has been done to study the BPSK modulation based DS-UWB communication system. Direct sequence spread spectrum (DSSS) technique along with UWB signal and two types of equalization techniques has been incorporated to mitigate the multipath fading effect associated with S-V indoor channel. Rake receiver has been used to utilize the energy of various delayed multipath components to improve the performance of the system. In short range communication process, indoor channel model or UWB channel model has been studied with different transmitter receiver separation, using some fundamental parameters of channel. Inter symbol interference (ISI) is a major problem in frequency selective fading channels, to overcome this problem, RAKE-MMSE equalizer and single carrier frequency domain equalizer (SC-FDE) have been incorporated. Thesis comprises of the system performance study and design done by using the above said equalization techniques for DS-UWB communications system

Cognitive MAC protocols for mobile Ad-Hoc networks

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The term of Cognitive Radio (CR) used to indicate that spectrum radio could be accessed dynamically and opportunistically by unlicensed users. In CR Networks, Interference between nodes, hidden terminal problem, and spectrum sensing errors are big issues to be widely discussed in the research field nowadays. To improve the performance of such kind of networks, this thesis proposes Cognitive Medium Access Control (MAC) protocols for Mobile Ad-Hoc Networks (MANETs). From the concept of CR, this thesis has been able to develop a cognitive MAC framework in which a cognitive process consisting of cognitive elements is considered, which can make efficient decisions to optimise the CR network. In this context, three different scenarios to maximize the secondary user's throughput have been proposed. We found that the throughput improvement depends on the transition probabilities. However, considering the past information state of the spectrum can dramatically increases the secondary user's throughput by up to 40%. Moreover, by increasing the number of channels, the throughput of the network can be improved about 25%. Furthermore, to study the impact of Physical (PHY) Layer errors on cognitive MAC layer in MANETs, in this thesis, a Sensing Error-Aware MAC protocols for MANETs has been proposed. The developed model has been able to improve the MAC layer performance under the challenge of sensing errors. In this context, the proposed model examined two sensing error probabilities: the false alarm probability and the missed detection probability. The simulation results have shown that both probabilities could be adapted to maintain the false alarm probability at certain values to achieve good results. Finally, in this thesis, a cooperative sensing scheme with interference mitigation for Cognitive Wireless Mesh Networks (CogMesh) has been proposed. Moreover, a prioritybased traffic scenario to analyze the problem of packet delay and a novel technique for dynamic channel allocation in CogMesh is presented. Considering each channel in the system as a sub-server, the average delay of the users' packets is reduced and the cooperative sensing scenario dramatically increases the network throughput 50% more as the number of arrival rate is increased

A General Framework for Analyzing, Characterizing, and Implementing Spectrally Modulated, Spectrally Encoded Signals

Fourth generation (4G) communications will support many capabilities while providing universal, high speed access. One potential enabler for these capabilities is software defined radio (SDR). When controlled by cognitive radio (CR) principles, the required waveform diversity is achieved via a synergistic union called CR-based SDR. Research is rapidly progressing in SDR hardware and software venues, but current CR-based SDR research lacks the theoretical foundation and analytic framework to permit efficient implementation. This limitation is addressed here by introducing a general framework for analyzing, characterizing, and implementing spectrally modulated, spectrally encoded (SMSE) signals within CR-based SDR architectures. Given orthogonal frequency division multiplexing (OFDM) is a 4G candidate signal, OFDM-based signals are collectively classified as SMSE since modulation and encoding are spectrally applied. The proposed framework provides analytic commonality and unification of SMSE signals. Applicability is first shown for candidate 4G signals, and resultant analytic expressions agree with published results. Implementability is then demonstrated in multiple coexistence scenarios via modeling and simulation to reinforce practical utility

Power control for WCDMA

This project tries to introduce itself in the physical implementations that make possible the denominated third generation mobile technology. As well as to know the technology kind that makes possible, for example, a video-call in real time. During this project, the different phases passed from the election of WCDMA like the access method for UMTS will appear. Its coexistence with previous network GSM will be analyzed, where the compatibility between systems has been one of the most important aspects in the development of WCDMA, the involved standardization organisms in the process, as well as the different protocols that make the mobile communications within a network UTRAN possible. Special emphasis during the study of the great contribution that has offered WCDMA with respect to the control of power of the existing signals will be made. The future lines that are considered in the present, and other comment that already are in their last phase of development in the field of the mobile technology. UMTS through WCDMA can be summarized like a revolution of the air interface accompanied by a revolution in the network of their architecture

Adaptive Resource Allocation Strategies for Dynamic Heterogeneous Traffic in Td-cdma/Tdd Systems

The purpose of this study was to investigate the co-channel interference present in TD-CDMA/TDD systems and TDMA/TDD systems and propose methods to avoid the co-channel interference. Time Slot Opposing algorithm which avoids co-channel interference in TD-CDMA/D-TDD system is reviewed as part of background study. The interference scenarios in TDMA/D-TDD systems are then studied and methods to avoid co-channel interference are proposed. The algorithms are then tested using real Internet data traffic to obtain a realistic analysis. Based on the background research, an extended Max {SIR} algorithm is proposed to avoid co-channel interference in TDMA/D-TDD systems. This algorithm is a centralized dynamic channel allocation algorithm that uses information from all the cells in the system to avoid co-channel interference and increase the signal power-to-interference power outage probability ratio. The proposed algorithm is then applied to a TDMA/D-TDD system that have subscribers grouped based on priority. As a last step of the research, traffic in TDMA/D-TDD systems is modeled using the ON-OFF traffic modeling and the Max {SIR} algorithm is applied. The results obtained using ON-OFF traffic modeling matched with the results obtained using analytical simulations.School of Electrical & Computer Engineerin

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression