In this paper, we will discuss how to provide multiple-data-rate transmissions in a contemporary IEEE 802.11 infrastructure wireless network. According to the characteristics of modulation schemes, the highest data rate between a pair of mobile stations will be inversely proportional with the transmission distance. Therefore, a moving mobile station is requested to dynamically adjust its modulation scheme to achieve maximal network throughput as well as to keep the connection alive. In this paper, we propose a hybrid handshake protocol with a simple broadcasting protocol to help mobile stations to obtain the necessary location information. The critical fairness problem of multi-rate wireless networks is also discussed and solved in this paper.

We design a novel fuzzy controller to dynamically adjust the packet length to protect against the interference from microwave oven over the IEEE 802.11 FHSS (frequency hopping spread spectrum) wireless LAN card. The idea of adjusting the packet length under the noise environment from the measurement results about the effects of microwave ovens over the wireless LAN card is referred by Lee, Sheu, Chen, Yu and Huaung (see APCC/OECC'99, p.817-820, 1999). Simulation results show that the designed fuzzy controller can effectively improve the transmission performance in terms of network throughput.

The integrated technology of a novel prediction system with a high prediction accuracy for indoor wireless LAN is proposed. Different from conventional methods, the genetic algorithm and neural network are employed to compute the environmental parameters and enhance the prediction accuracy, respectively.

A study of the multichannel coherent CPFSK communication system employing Reed-Solomon codes is reported. The crosstalk between adjacent channels, the impact of the laser phase noise, and selection of the optimum code rate are investigated. By applying a suitable coding scheme, the laser linewidth can be greatly relaxed, and the receiver sensitivity will be remarkably improved. A 100 Mbit/s system is used to verify the coding benefit. The results show that the impact of the laser linewidth can be largely alleviated by applying a (255, 223) Reed-Solomon code. When the linewidth is fixed (/spl Delta//spl nu/T=2%), this code can improve the receiver sensitivity by more than 15 dB.

A detailed analysis of optical coherent phase diversity single-filtered and dual-filtered frequency-shift keying (FSK) receivers corrupted by shot and phase noise is presented. With delay and cross-product detection, the effect of various parameters, including bandwidths of filters, delay time, frequency deviation and noises, are investigated. The tolerance of phase noise is quite large, when small time delay in the demodulator and appropriately large frequency deviation is selected. It is also shown that there exists an optimal bandwidth for the first filter in the dual-filtered FSK receiver. For a total linewidth equal to half of the bit rate, the power penalty incurred (at BER=10/sup -9/) is 1.92 dB when the modulation index is 4, provided that an optimal filter bandwidth and a frequency deviation-delay product of 0.25 are used.>