| Summary: | 博士 === 淡江大學 === 電機工程學系博士班 === 101 === Quality improvement of communication systems by multiple-input multiple-output and relays in real environments are investigated. The channel statistics parameters of ultra wide band (UWB) and wireless local area network (WLAN) are computed by applying shooting and bouncing ray/image (SBR/Image) techniques. First, a comparison of multiple-input multiple-output (MIMO) WLAN communication characteristics for six different geometrical shapes is investigated. These six shapes include the straight shape corridor with rectangular cross section, the straight shape corridor with arched cross section, the curved shape corridor with rectangular cross section, the curved shape corridor with arched cross section, L-shape corridor, and T-shape corridor. The frequency responses and impulse responses of these corridors are computed by applying SBR/Image techniques. By using the frequency responses and impulse response of these multi-path channels, the channel capacity and statistic parameters for these six corridors could be obtained.
The second part, the genetic algorithm （GA）, particle swarm optimization （PSO）, asynchronous particle swarm optimization （APSO） and dynamic differential evolution （DDE） are used to optimizing the objective functions (criterion for measuring the effectiveness of the obtained optimized algorithm solution) and solved in indoor MIMO-WLAN communication system. The optimal locations of the transmitter antenna for channel capacity in indoor environment MIMO-WLAN wireless communication systems are evaluated in the whole indoor environment. The channel capacity is chosen as the objective function. Based on the SBR/Image performance, the channel capacity for any given location of the transmitter can be computed. The optimal transmitting antenna location for maximizing the channel capacity is searched by algorithms. Obtained simulation results illustrate the feasibility of using the integrated ray-tracing, and optimization methods to find the optimal transmitter locations in determining the optimized channel capacity of a wireless network. Numerical results show that the performance for increasing of channel capacity by optimization algorithm is quite good. The investigated results can help communication engineers improve their planning and design of indoor wireless communication.
The third part, an optimization procedure for the location of the transmitter antenna and relay transceiver in UWB wireless communication system is presented. The impulse responses of different transmitter antenna and transceiver locations are computed by SBR/Image techniques and inverse fast Fourier transform (IFFT). By using the impulse responses of these multi-path channels, the bit error rate (BER) performance for binary pulse amplitude modulation (BPAM) impulse radio UWB communication system are calculated. Based on the BER performance, the outage probability for any given transmitter antenna and relay location of the transceiver can be computed. The optimal transmitter antenna and relay antenna location for minimizing the outage probability is searched by GA, PSO, APSO and DDE. Numerical results have shown that our proposed method is effective to find the optimal location for transmitter antenna and relay antenna.
The fourth part, the dissertation focuses on the research of channel capacity of MIMO-WLAN system with co-channel interference (CCI) in indoor environment. The channel capacities are calculated based on the realistic environment. First, channel capacities of the MIMO-WLAN system without and with CCI are calculated for both single and multiple transmitting antennas of the CCI. Next, the channel capacities by using simple uniform linear array (ULA) and polarization diversity array (PDA) deployment are calculated. According to the results, for the case without CCI channel capacity of ULA is better than that of PDA in indoor wireless communication. However, the channel capacity for the PDA is better than that for of ULA when interference exists.
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