Dissertation > Excellent graduate degree dissertation topics show

Doppler Shift Effect on OFDMA in Mobile Wimax

Author: YueHan
Tutor: LiuWei
School: Huazhong University of Science and Technology
Course: Information and Communication Engineering
Keywords: Mobile WiMax OFDMA Doppler Shift pilot signals Frequency Bank Signal (FBS)
CLC: TN929.531
Type: Master's thesis
Year: 2009
Downloads: 17
Quote: 0
Read: Download Dissertation

Abstract


Wireless communication fast development and accessibility to an increasing number of users in the recent years have placed much demand on broadband wireless access (BWA) technology that has attracted much attention. As a BWA solution, Worldwide Interoperability for Microwave Access (WIMAX) is accepted by carriers of worldwide for broadband wireless service. It can be classified as fixed WIMAX (IEEE 802.16d version) using OFDM transmitting technique and mobile WIMAX (IEEE 802.16e version) using OFDMA transmitting technique. One of the main benefits of those transmitting techniques in wireless communication is that the receiver does not need to constantly adapt an equalizer as a single carrier system would. They also show much favorable properties such as high spectral efficiency, robustness to channel fading, immunity to impulse interference, capability of handling very strong echoes (multipath fading). But one of their main drawbacks is the sensitivity to frequency errors caused by the frequency differences between the local oscillators in the transmitter and the receiver.In mobile radio environment these frequency errors are due to the relative movement between transmitter and receiver. It is known as the Doppler frequency shifts phenomenon which causes a broadening of the signal spectrum.The main purpose of this thesis is to study the effect of Doppler Shift on OFDMA modulation technique conducting to orthogonality destruction which in its turn leads to ICI. The method of Frequency Bank Signal (FBS) based on Walsh functions is described in order to combat high Doppler Shift impairment suffered by mobile wireless communication system like Mobile WiMax. FBS is a hybrid of CDMA and OFDMA but without pilots signals (used for estimation) whose effect becomes negative in signal reception in a high Doppler shift environment.Simulations are conducted by using MATLAB codes to evaluate the different performances of BER between OFDMA with and without pilots in Rayleigh environment. The comparison study shows that OFDMA without pilots in presence of Doppler Shift gives better performance of BER compared to OFDMA with pilots in presence of high Doppler Shift.

Related Dissertations

  1. Research on Synchronizationalgorithm of WiMAX Physical Layer Based on IEEE802.16e,TN929.531
  2. The Design of the Synchronization Algorithms for IEEE 802.16m,TN929.5
  3. High-speed railway and tunnel wireless coverage solutions,TN929.5
  4. Spread spectrum communication system command synchronization of pseudo-code,TN914.42
  5. The Anti-Doppler Technology of LTE Downlink System in High-Speed Railway Scenario,U285
  6. IMT-A system in consideration of the space-time QoS class frequency domain resource allocation techniques,TN929.5
  7. The Improment of High Dynamic Carrier Capture Technology Based on Discrete Match Fourier Transform,V243.2
  8. Wimax Network Planning and Design Based on ASSET Simulation Platform,TN925
  9. Research on Adaptive Resource Allocation for OFDMA System Based on Intellight Optimization Algorithms,TN929.531
  10. Research on Multi-parameter Estimation Algorithms of Underwater Acoustic Channel Based on FRFT,TN929.3
  11. The Research and Pracice of Jiangxi Unicom GSM High-Speed Rail Coverage Solusion,TN929.532
  12. Performance Analysis of Multi-User Scheduling Schemes in MIMO Systems,TN919.3
  13. Comparison Peak-to-Average Power Ratio of Single Carrier FDMA and OFDMA,TN929.531
  14. Research on Resource Allocation Algorithm in OFDMA Systems,TN929.531
  15. The Research of Doppler Frequency Shift Compensation in OFDM Underwater Acoustic Communication System,TN929.3
  16. Load Balancing Technology for OFDMA Networks,TN929.531
  17. Research on Resource Allocation Algorithms Based on OFDMA Systems,TN929.531
  18. Research on Radio Resource Allocation in Cooperative OFDMA Systems,TN929.531
  19. PMF-FFT based Fast Acquisition Algorithm and Implementation,TN914.42
  20. Research on Correlation Technologies of Directional Broadband Data Link,TN919.2
  21. Doppler Searching Algorithm in the GPS System,P228.4

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Wireless communications > Mobile Communications > Cellular mobile communications systems (mobile phones, mobile phone handsets ) > Frequency division multiple access (FDMA) mobile communication
© 2012 www.DissertationTopic.Net  Mobile