Based On Chirp Ultra-wideband Communication Technology

Ultra-wideband (UWB) wirelss communication technology, which achieves ultra-bandwidth, high-speed data transmission within a short distance, has became the new favorite of short-range wireless communication. In 2007, the ultra-wideband communication technology based on chirp spectrum spread approved into IEEE 802.15.4a Physical Layer Standard has great potential for development of new wireless communication technology in the field of future's wireless communications. For its good performance for hiding, anti-multipath and narrowband interference capability, high transmission rate, large system capacity, penetration ability, low power consumption, system complexity, and so on, besides, it can re-use the spectrum to solve the spectrum congestion phenomenon.Chirp UWB communication technology attracted wide attention from researchers.Based on the basic theory of Chirp UWB communication technology, we study the modulation technology, timing synchronization schemes and the hardware realization of the structure, design and implement the key technology verification system of Chirp UWB wireless communications.we do lots of experiments on the verification platform to verify various characteristics of Chirp UWB technology, modulation schemes, and synchronization technology, and prove the feasibility of short-range Chirp UWB wireless communication. The study includes the following aspects:We introduce the features of short-range indoor wireless channel. The direct-sequence and frequency hopping spread spectrum technology are promising techniques to mitigate the multipath-fading, but the high speed PN generator in the two systems is hard to be implemented. This thesis studies the chirp spread spectrum technology to avoid such problems and comprehensively introduces the Chirp UWB technology including pulse compression technology, principles of chirp spread spectrum as well as the features of Chirp UWB system.The thesis has summarized the Chirp UWB communication system's modulation scheme and timing synchronization technique. Binary orthogonal keying (BOK) is the most common modulation method, chirp signal is used to indicate the modulated symbol, but the transmission rate is not high, the improved modulation scheme based on quaternary bi-orthogonal keying (QBOK) can provide double transmission rate than BOK. In direct modulation (DM) method, chirp signal is only used to spread the spectrum of modulated signal, high order modulation can be used in the DM scheme to enhance the transmission rate. As the complexity of hardware implementation circuit which is based on power spectrum estimation, the system solution adopts timing synchronization method which is based on feedback, joint channel and timing estimation. Finally, the thesis put forward four easy-implemented system solutions based on different modulation schemes.This paper designs the easy-implemented full-digital hardware implementation circuits for Chirp UWB systems using four modulation schemes including BOK, QBOK, DBPSK+DM as well as 16QAM+DM and then completes its FPGA implementations with Verilog hardware description language, which evaluate the time synchronization methods based on the feedback , joint channel and timing estimation respectively. Besides, the performance is tested in universal software radio hardware platform and the tested results match well with the theoretical analysis.The verification system is built to provide the hardware solutions of Chirp UWB wireless communications and verify the existing and future proposed key technology and algorithms. To evaluate the performance of Chirp UWB systems exploiting the above-mentioned four modulation schemes at different communication distances, the BER performance verification circuits of frame synchronization methods using barker codes are designed respectively to calculate the corresponding BER. At last, we compare the corresponding resource occupation ratio.