The IEEE802.15.4 Low Rate-Wireless Personal Area Network (LR-WLAN) is characterized by its low power consumption, low cost, and reliable data transfer. LR-WPAN can be used for security monitoring, by automatically setting various sensors which can be placed anywhere in the factory or home. This work implements baseband signal processing and circuit design for the 868/915MHz mode of the IEEE802.15.4 LR-WPAN. The development processes include algorithm design, system simulation, FPGA implementation and system measurements. The receiver algorithm includes packet detection, phase mapping, frequency offset estimation, energy detection, synchronization, despreading and differential decoding. All algorithms are completely described herein. The system simulation match the required specifications after running the algorithms. Additionally, algorithms are composed by the Verilog Hardware Description Language (VHDL) form. The process is designed according to the hardware to identify exactly each link . The simulations performed in this work include behavioral simulation and gate level simulation. Finally, the program is uploaded to the FPGA to verify results of the procedures is verified by Matlab, by determining the effects of transmission on the channel signal, including idle signals, initial phase, frequency offset and noise. The frequency offset arises when the oscillators of the transmitter and receiver do not match. The transmitter signal from the logic analyzer is then input to the FPGA. The signal sent from the logic analyzer is tested to determine whether it retains the original transmission signal homology. Finally, a LR-WPAN baseband circuit is successfully developed through by the above procedures.

Approved for public release; distribution is unlimited / OFDM systems have experienced increased attention in recent years and have found applications in a number of diverse areas including telephone-line based ADSL links, digital audio and video broadcasting systems, and wireless local area networks (WLAN). Orthogonal frequency-division multiplexing (OFDM) is a powerful technique for high data-rate transmission over fading channels. However, to deploy OFDM in a WLAN environment, precise frequency synchronization must be maintained and tricky frequency offsets must be handled. In this thesis, various techniques to improve the data throughput of OFDM WLAN are investigated. A simulation tool was developed in Matlab to evaluate the performance of the IEEE 802.11a physical layer. We proposed a rapid time and frequency synchronization algorithm using only the short training sequence of the IEEE 802.11a standard, thus reducing the training overhead to 50%. Particular attention was paid to channel coding, block interleaving and antenna diversity. Computer simulation showed that drastic improvement in error rate performance is achievable when these techniques are deployed. / Lieutenant, Hellenic Navy