TD-SCDMA Relay Networks

PhDWhen this research was started, TD-SCDMA (Time Division Synchronous Code Division Multiple Access) was still in the research/ development phase, but now, at the time of writing this thesis, it is in commercial use in 10 large cities in China including Beijing and Shang Hai. In all of these cities HSDPA is enabled. The roll-out of the commercial deployment is progressing fast with installations in another 28 cities being underway now. However, during the pre-commercial TD-SCDM trail in China, which started from year 2006, some interference problems have been noticed especially in the network planning and initialization phases. Interference is always an issue in any network and the goal of the work reported in this thesis is to improve network coverage and capacity in the presence of interference. Based on an analysis of TD-SCDMA issues and how network interference arises, this thesis proposes two enhancements to the network in addition to the standard N-frequency technique. These are (i) the introduction of the concentric circle cell concept and (ii) the addition of a relay network that makes use of other users at the cell boundary. This overall approach not only optimizes the resilience to interference but increases the network coverage without adding more Node Bs. Based on the cell planning parameters from the research, TD-SCDMA HSDPA services in dense urban area and non-HSDPA services in rural areas were simulated to investigate the network performance impact after introducing the relay network into a TD-SCDMA network. The results for HSDPA applications show significant improvement in the TDSCDMA relay network both for network capacity and network interference aspects compared to standard TD-SCDMA networks. The results for non- HSDPA service show that although the network capacity has not changed after adding in the relay network (due to the code limitation in TD-SCDMA), the TD-SCDMA relay network has better interference performance and greater coverage

Traffic agents for improving QoS in mixed infrastructure and ad hoc modes wireless LAN

As an important complement to infrastructured wireless networks, mobile ad hoc networks (MANET) are more flexible in providing wireless access services, but more difficult in meeting different quality of service (QoS) requirements for mobile customers. Both infrastructure and ad hoc network structures are supported in wireless local area networks (WLAN), which can offer high data-rate wireless multimedia services to the mobile stations (MSs) in a limited geographical area. For those out-of-coverage MSs, how to effectively connect them to the access point (AP) and provide QoS support is a challenging issue. By mixing the infrastructure and the ad hoc modes in WLAN, we propose in this paper a new coverage improvement scheme that can identify suitable idle MSs in good service zones as traffic agents (TAs) to relay traffic from those out-of-coverage MSs to the AP. The service coverage area of WLAN is then expanded. The QoS requirements (e.g., bandwidth) of those MSs are considered in the selection process of corresponding TAs. Mathematical analysis, verified by computer simulations, shows that the proposed TA scheme can effectively reduce blocking probability when traffic load is light

M-Business: Economy Driver or a Mess?

Reports about mobile wireless technology in the media may be confusing. While we know that the telecommunication industry is in distress, we also observe a phenomenal, indeed unprecedented explosion of the use of mobile wireless devices and services all over the globe. This paper presents a balanced introduction to wireless technology including devices, mobile operating systems, and communication protocols. It discusses standardization efforts, technology evolution paths, and several new and potentially disruptive technologies, some still in the research stage. The paper lists leading global wireless service providers in terms of the number of domestic subscribers and presents an analysis of the six U.S. national operators including their strengths and weaknesses. Only four of them are profitable now. Although the consumer market currently dictates technology evolution, several examples of successful business applications of wireless mobile technology are presented. Finally, the question presented in the title is addressed

Balancing Between ‘De Facto’ and ‘De Jure’ in Standard-setting Strategy by a Latecomer Country: The Case of ICT Industry in China

The main objective of this study is to gain insights into the complexities of the standard-setting process involving a latecomer country. Standards are identified into two categories: market (de facto) standards arising from market interactions and formal standards (de jure) arising from mandatory specifications by public authorities. The study focused on two research questions: (i) What are the different factors that influence the outcome (success or failure) of a proposed standard by a latecomer country? (ii) How does a latecomer country navigate between de facto standard and de jure standard? It analysed two cases (WAPI - a failure and TD-SCDMA - a success) to examine the extent of government support for a standard setting that needs to balance between the de facto standard and de jure standard. The study found that standard competition is a complicated interplay between technology, markets, politics and institutions. The experience of two cases suggest that a proposed standard should judiciously combine partly a ‘de jure standard’ which aims to protect national interests and achieve a national goal, and partly the ‘de facto standard’ to meet the technology trend, market demand, as well as the end users’ welfare. Keywords: Standardization, Latecomer country, Latecomer catch-up, De Facto standards, De June standards, ICT Industr

Joint optimization of transmission-order selection and channel allocation for bidirectional wireless links-part II: algorithms

This is the second in a two-part series of papers on transmission order (TO) optimization in the presence of channel allocation (CA), i.e., joint optimization of the TO selection and CA problem, for interfering bidirectional wireless links. Part I of this paper thoroughly analyzes the joint optimization problem from a game theoretic perspective for a general deterministic setting. Here in Part II, we present novel distributed and centralized CA-TO algorithms, together with their performance analysis, for Device-to-Device (D2D) communications underlaying cellular networks based on the findings in Part I of this paper. Here, TO is a novel dimension for optimization. In Part II, we propose and analyze novel two distributed and one centralized joint CA-TO algorithms. Our investigations show that: i) our algorithms contain many of the existing TO algorithms and CA algorithms as its special cases and can thus be considered as a general framework for the joint CA and TO optimization. The computer simulations for TDD-based D2D communications underlaying cellular network show that the proposed distributed and centralized joint CA-TO algorithms remarkably outperform the reference algorithms.IEEE Communications Societ

Wireless Signals and Male Fertility

Rapid advances in wireless technology have increased the number of users of mobile devices. As of 2011, the number of cell phone subscribers have reached 5.3 billion worldwide. Mobile devices have saturated our environment with radio frequency (RF) signals. This situation has created public concern over the effect of such signals on human health. This dissertation focuses on the correlation of RF signals emitted by cell phones with male infertility. A thorough discussion is provided on the effects of RF signals on the development of central nervous system (CNS) neoplasm, the design of these mobile devices, the range of the RF frequencies they emit, the power with which they operate, their specific absorption rate (SAR), the distance between the user and the device while in use, how and where the devices are used, the duration of usage, and the accumulated exposure associated with the use of multiple RF devices. The results of our reviews and experimental in vitro studies show a significant correlation between the usage of mobile phones and human semen parameters, with a decrease in motility and viability, and an increase in the reactive oxygen species (ROS) score. However, in daily usage, a cell phone kept in proximity to the groin is separated from the testes by multiple layers of tissue. To explore this effect, a computational model of scrotal tissues was designed. Our results show that during in vitro experimentation, an effect equivalent to real-life conditions can be obtained by placing the cell phone a few centimeters farther away from the semen sample. The results of our study can be used to calculate the equivalent distance between a radiation source and a semen sample, and to set up in vitro experiments that mimic real-life condition

Wireless Signals and Male Fertility

Rapid advances in wireless technology have increased the number of users of mobile devices. As of 2011, the number of cell phone subscribers have reached 5.3 billion worldwide. Mobile devices have saturated our environment with radio frequency (RF) signals. This situation has created public concern over the effect of such signals on human health. This dissertation focuses on the correlation of RF signals emitted by cell phones with male infertility. A thorough discussion is provided on the effects of RF signals on the development of central nervous system (CNS) neoplasm, the design of these mobile devices, the range of the RF frequencies they emit, the power with which they operate, their specific absorption rate (SAR), the distance between the user and the device while in use, how and where the devices are used, the duration of usage, and the accumulated exposure associated with the use of multiple RF devices. The results of our reviews and experimental in vitro studies show a significant correlation between the usage of mobile phones and human semen parameters, with a decrease in motility and viability, and an increase in the reactive oxygen species (ROS) score. However, in daily usage, a cell phone kept in proximity to the groin is separated from the testes by multiple layers of tissue. To explore this effect, a computational model of scrotal tissues was designed. Our results show that during in vitro experimentation, an effect equivalent to real-life conditions can be obtained by placing the cell phone a few centimeters farther away from the semen sample. The results of our study can be used to calculate the equivalent distance between a radiation source and a semen sample, and to set up in vitro experiments that mimic real-life condition

On Content-centric Wireless Delivery Networks

The flux of social media and the convenience of mobile connectivity has created a mobile data phenomenon that is expected to overwhelm the mobile cellular networks in the foreseeable future. Despite the advent of 4G/LTE, the growth rate of wireless data has far exceeded the capacity increase of the mobile networks. A fundamentally new design paradigm is required to tackle the ever-growing wireless data challenge. In this article, we investigate the problem of massive content delivery over wireless networks and present a systematic view on content-centric network design and its underlying challenges. Towards this end, we first review some of the recent advancements in Information Centric Networking (ICN) which provides the basis on how media contents can be labeled, distributed, and placed across the networks. We then formulate the content delivery task into a content rate maximization problem over a share wireless channel, which, contrasting the conventional wisdom that attempts to increase the bit-rate of a unicast system, maximizes the content delivery capability with a fixed amount of wireless resources. This conceptually simple change enables us to exploit the "content diversity" and the "network diversity" by leveraging the abundant computation sources (through application-layer encoding, pushing and caching, etc.) within the existing wireless networks. A network architecture that enables wireless network crowdsourcing for content delivery is then described, followed by an exemplary campus wireless network that encompasses the above concepts.Comment: 20 pages, 7 figures,accepted by IEEE Wireless Communications,Sept.201

Cooperative Transmission Protocols with High Spectral Efficiency and High Diversity Order Using Multiuser Detection and Network Coding

Cooperative transmission is an emerging communication technique that takes advantages of the broadcast nature of wireless channels. However, due to low spectral efficiency and the requirement of orthogonal channels, its potential for use in future wireless networks is limited. In this paper, by making use of multiuser detection (MUD) and network coding, cooperative transmission protocols with high spectral efficiency, diversity order, and coding gain are developed. Compared with the traditional cooperative transmission protocols with single-user detection, in which the diversity gain is only for one source user, the proposed MUD cooperative transmission protocols have the merits that the improvement of one user's link can also benefit the other users. In addition, using MUD at the relay provides an environment in which network coding can be employed. The coding gain and high diversity order can be obtained by fully utilizing the link between the relay and the destination. From the analysis and simulation results, it is seen that the proposed protocols achieve higher diversity gain, better asymptotic efficiency, and lower bit error rate, compared to traditional MUD and to existing cooperative transmission protocols.Comment: to appear, in the proceedings of IEEE International Conference on Communications, Glasgow, Scotland, 24-28 June 200