Design and Implementation of Baseband Transceiver with Adaptive MIMO-OFDM Technology
Date Issued
2014
Date
2014
Author(s)
Cheng, Yi-Feng
Abstract
Based on the perspective of system design, this thesis proposed an integrated adaptive MIMO OFDM system. We dedicated to realize the whole baseband receiver with hardware language and yet to integrate the system on FPGA with Universal Software Radio Peripheral (USRP) to complete the system verification. In this thesis, we define the system specification based on IEEE 802.11n, and proposed the architecture of adaptive MIMO OFDM transceiver with hardware circuit design. The primary modules of the baseband circuit are composed of initial acquisition, tracking loop, channel estimation, data recovery, CSI feedback, and noise variance estimation. We exploited legacy short/long training field to implement initial acquisition including packet detection, coarse/fine symbol boundary detection, and coarse/fine frequency offset estimation. Also in this thesis we proposed an improved method of CSBD which can mitigate the false alertion from data symbols, and by normalized delayed correlation, the value of threshold will be easier to set. Tracking loop which we use pilots among data symbols to estimate is for residual CFO and SCO. To accelerate the speed and to lower computation, we came out an intuitive approach to derive the solution of SVD, yet the drawback of this approach is that it is not expandable for higher dimension of antennas. We implemented two MIMO detection methods including VBLAST and SVD transmission while the later is for the purpose of adaptive transmission. And we used high throughput long training field to estimate noise variance based on the concept of ren’s estimator. Other than hardware architecture, we have also proposed two methods of adaptive modulation. In the first method, the computation is relatively low compared to the previous work of our group. The second method achieves higher throughput while still meets the JAER (Just Acceptable Error Rate). The most important contribution of this thesis is to realize the whole adaptive MIMO OFDM system by integrating the hardware design on FPGA and Universal Software Radio Peripheral (USRP). Lastly, we proved that the system is feasible with real-time field trial and demodulation of the signal over the air instantly.
Subjects
Baseband transceiver design
Adaptive MIMO OFDM Technique
FPGA Verification
Software Defined Radio Platform
Real-time System
Type
thesis
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