| Beginning with a study on the performance of IEEE802.16-2004 based system in military specialized environment where jamming is prominence, this paper focuses on system performance enhancement in jamming environment via link adaptation. Two types of jamming are considered: multitone pilot jamming and partial-band jamming.
The results of computer simulation show that the system is vulnerable to jamming. Further, multitone pilot jamming degrades the system performance more severely than partial-band jamming, when jamming resource is of limited power. A robust characteristic is observed from the standard newly defined operation mode, ‘BPSK 1/2’, under most of the jamming scenarios.
Accordingly, a practical mean carrier-to-interference-noise ratio (CINR) based link adaptation algorithm is proposed with merit that it requires no change to the current protocol. In the assumed jamming scenario, the system with link adaptation and systems with fixed operation mode are tested and compared. The simulation results verify that the system operating in jamming environment achieves performance improvement from both throughput and service stability aspects by applying the proposed link adaptation algorithm. A parameter ‘imperfectness’ is introduced to evaluate the algorithm. Higher efficiency is found in system under partial-band jamming. An optimal value of α used for estimating the mean CINR is proposed to be around 0.3.
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| Juan Li received the B.S. degree in Automatic Control from Central South University, China, in 1995. In 2002 and 2006 she received the M.S degree and Licentiate degree in Communication Engineering from Helsinki University of Technology (HUT), Finland. She is currently a Ph.D student and working as a researcher in the Communications Laboratory, HUT. During the years 2002 and 2003, she worked also as a special teacher assistant in the Communications Laboratory. She has been involved in several research projects including System Technology for Future Wireless Telecommunications, OCDMA, Ad Hoc architecture and WiMAX. She is interested in mobile WiMAX network, cellular networks, and optical fiber network. In particular, she specializes in radio resource management, OFDM, and channel modeling.
Sven-Gustav Häggman received his master’s, licentiate and doctor’s degrees in Communications Engineering from Helsinki University of Technology in 1970, 1979, and 1991, respectively. He has been with the Communications Laboratory at HUT since 1970, until 1991 in various teaching and research positions, since 1991 as associate professor and since 1998 as professor in radio communications. His activities have included research in microwave terrestrial radio relay system planning and l.o.s.-channel measurement and modeling. Presently he is conducting research on mobile radio channel measurement and modeling, radio interface techniques, cellular radio network planning, and radio resource management methods. |