Abstract
Orthogonal frequency division multiplexing (OFDM) is a very hotresearch topic in the recent years, and IEEE 802.11a is anOFDM-based wireless local area network (LAN) standard. In thisthesis, we adopt the physical layer specification in the IEEE802.11a standard. The channel considered is a multipath channelwith additive white Gaussian noise (AWGN), which is static duringa packet and is different for different packets. Baseband receiveralgorithms including channel estimation, detection, and decodingare the main focus of this work. In particular, we investigatealgorithms for combined detection and decoding. The obtainedsimulation results show that our combined algorithm performs wellin comparison with separate detection and decoding, and has hightolerance to delay spread.From the simulation results, we can see that the channelestimation method proposed in the thesis has good performance. Ifthe maximum delay spread is smaller than the guard interval, thenthe MSE is just the same as that of the case of no delay spread.On the other hand, we have shown by simulation that our receiverhas high tolerance to the delay spread. Even if the maximum delayspread is larger than the guard interval, the influence of delayspread to the MSE and PER is not very significant. When PER is0.1, the PER difference between the cases 50 to 300 ns is about 2dB. Although our channel estimator is only designed for thecondition that the maximum delay spread is smaller than the guardinterval, it still works well when the maximum delay spread islarger than the guard interval.On the other hand, for the combined detection and decodingalgorithms proposed in the thesis, the simulation results showthat SDDA have much better performance than HDDA. At PER =0.1, SDDA is better than HDDA by 3 dB for AWGN channel andSDDA3 is better than HDDA by 4 to 5 dB for AWGN + multipathchannel.