Performance Enhancement for Wireless Networks: Modulation, Clock Synchronization and Resource Management
| dc.contributor.author | Yang, Zhe | |
| dc.contributor.supervisor | Cai, Lin | |
| dc.date.accessioned | 2013-05-08T20:08:51Z | |
| dc.date.available | 2013-05-08T20:08:51Z | |
| dc.date.copyright | 2013 | en_US |
| dc.date.issued | 2013-05-08 | |
| dc.degree.department | Department of Electrical and Computer Engineering | |
| dc.degree.level | Doctor of Philosophy Ph.D. | en_US |
| dc.description.abstract | Wireless networks become more and more important in modern information systems as the last mile/meter solutions, thanks to the flexibility of mobile access to facilitate Internet access anytime, anywhere. Given the limited resources, e.g., spectrum and energy supplies, to meet the ever increasing demand for wireless data services, new approaches are beckoned to enhance the spectrum and energy efficiency. We investigate this problem from three important aspects, digital modulation, clock synchronization and concurrent transmission scheduling. The contributions of this dissertation are four-fold. First, we employ the cross-layer design to explore the spatial diversity and broadcast nature of wireless links and propose a novel network modulation scheme that can superpose the information bits of different priorities into one symbol. It offers a new dimension to improve the network throughput since we can flexibly configure the transmission according to the channels among transceivers. Moreover, it is compatible with the main-stream hardware and we just need a software upgrade to implement the idea. Second, we propose modulation schemes based on hexagonal tiling, which is known to be the most compact way of two-dimensional regular tiling. In order to fully utilize the advantage of hexagonal constellation, we employ the non-binary error controlcoding since the number of constellation points of hexagonal constellation is not necessarily to be an integer power-of-two. The feasibility of these new modulation schemes is verified by the prototype system based on the software defined radio platform USRP2 and GNU Radio. Third, to facilitate a wide range of wireless communications technologies and protocols, clock synchronization among several wireless devices is a fundamental requirement. We investigated this problem by tracing to the source of clock desynchronization, which is the clock skew. However, as shown by measurement results, the clock skew is not constant and related to the working temperature. We propose a novel clock skew estimation algorithm that can leverage the temperature information to accurately estimate the clock skew. Based on the estimation results, we propose a clock synchronization scheme that can directly remove the clock skew according to the working temperature. Fourth, the traditional time-sharing based scheduling schemes usually schedule one transmission within certain area. The emerging broadband wireless devices can dynamically adjust the transmitted data rate according to the received signal to interference and noise ratio (SINR). Allowing concurrent transmissions may be more efficient, while optimal scheduling problem for concurrent transmissions is an NP-hard problem. We propose simple yet effective heuristic algorithms that can significantly improve the system throughput with moderate computational complexity. | en_US |
| dc.description.proquestcode | 0544 | en_US |
| dc.description.proquestemail | yangzhe2007@gmail.com | en_US |
| dc.description.scholarlevel | Graduate | en_US |
| dc.identifier.bibliographicCitation | [1] Z. Yang, L. Cai, Y. Luo, and J. Pan, “Topology-aware modulation and error-correction coding for cooperative networks,” IEEE JSAC, vol. 30, no. 2, pp. 379-387, Feb. 2012. | en_US |
| dc.identifier.bibliographicCitation | [2] Z. Yang, L. Cai, Y. Liu, and J. Pan, “Environment-Aware Clock Skew Estimation and Synchronization for Wireless Sensor Networks,” IEEE Infocom, Orlando, FL, USA, March 2012. | en_US |
| dc.identifier.bibliographicCitation | [3] Z. Yang, Y. Luo, and L. Cai, “Network Modulation: A New Dimension to Enhance Wireless Network Performance," IEEE Infocom'11, Shanghai, China, May 2011. | en_US |
| dc.identifier.bibliographicCitation | [4] Z. Yang, L. Cai and W. Lu, "Practical Concurrent Transmission Scheduling Algorithms for Rate-adaptive Wireless Networks," IEEE Infocom'10, Mar. 2010, San Diego, CA, USA. | en_US |
| dc.identifier.bibliographicCitation | [5] Z. Yang, J. Pan and L. Cai, "Adaptive clock skew estimation with Interactive Multi Model Kalman filter for sensor networks," IEEE ICC'10, May 2010, Cape Town, South Africa. | en_US |
| dc.identifier.uri | http://hdl.handle.net/1828/4603 | |
| dc.language | English | eng |
| dc.language.iso | en | en_US |
| dc.rights.temp | Available to the World Wide Web | en_US |
| dc.subject | wireless network | en_US |
| dc.subject | network modulation | en_US |
| dc.subject | hexagon modulation | en_US |
| dc.subject | clock synchronization | en_US |
| dc.subject | clock skew | en_US |
| dc.subject | concurrent transmission | en_US |
| dc.subject | scheduling | en_US |
| dc.title | Performance Enhancement for Wireless Networks: Modulation, Clock Synchronization and Resource Management | en_US |
| dc.type | Thesis | en_US |