The Key Technology Research, Based On The Ieee 802.16e Ofdma Physical Layer

IEEE 802.16e wireless MAN (WMAN) is a standard for a broadband access technology. As a mainstream technology in IEEE 802.16 standard,OFDM(orthogonal frequency division multiplexing) and OFDMA(orthogonal frequency division multiple access) technology has been widely applied to the physical layer of WIMAX systems. Especially the latter, it is the basis to support mobility IEEE802.16e standard. So the study of OFDMA technology has important practical significance.This paper based on the IEEE 802.16e standard, describes the IEEE 802.16 protocol architecture, the key technologies of IEEE802.16e-based OFDMA systems, and the OFDMA physical layer specification. Introduced the detailed process of channel coding in IEEE 802.16e protocol, including randomization, coding, interleaving, modulation, etc., focusing on the description of the coding techniques such as Convolutional Code (CC), Convolutional Turbo Code (CTC), Low Density Parity check Code (LDPC),and the decoding techniques such as Viterbi decoding algorithm, the maximum a posteriori (MAP) decoding algorithm, BP decoding algorithm. Then describes the OFDMA channel estimation techniques such as least-squares difference (LS), linear minimum mean square error (LMMSE), low-level linear minimum mean square error (LR-LMMSE). And on this basis we build a physical layer simulation platform in Matlab environment, through a combination of theoretical and simulation we discussed the performance and complexity of OFDMA physical layer based on given parameters. Finally introduced how to reducing the peak to average power ratio (PAPR).