Synchronization Technique for OFDM-Based UWB System

Synchronization issue is inevitable in all wireless communication receiver systems and it plays the key role to the system performance. Synchronization technique includes timing synchronization and frequency synchronization. Timing synchronization is to detect valid packet and the accurate start position of fast Fourier transform (FFT) window from noise. Frequency synchronization is to correct the phase error caused by the mismatch of local oscillator (LO) between transmitter and receiver. Synchronization technique has been extensively studied for years. Although UWB system can leverage on successful experiences of orthogonal frequency division multiplexing (OFDM), it cannot use the traditional synchronization technology directly due to the distinct features. In IEEE 802.15.3a standard, the specified emission power spectral density is only -41 dBm/MHz, which is extremely small compared with other wireless systems. It indicates that timing synchronization for UWB system should be robust in high noise environment. In addition, to satisfy 528 Msps throughput, the UWB baseband receiver system should be designed in parallel architecture. The inherent high complexity, the requirements of high performance, high speed, low cost and low power consumption make the design of synchronization blocks for UWB quite a challenge work. This chapter will be divided into three parts: timing synchronization, coarse frequency synchronization and fine frequency synchronization. The traditional algorithms and innovative methods with low complexity and good performance will be introduced. Architecture design of each part is also provided.