Boreal Aquatic Ecology

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Adaptive space-division multiple accesses (SDMA) are considered as an important and advanced option supported by the upcoming 4G-enabled technologies. These advanced antenna techniques are expected to have a significant impact on the capacity and service quality provided by wireless links and the efficient use of the available spectrum. These systems can be used to simultaneously access different subscriber stations in the same overlapping coverage area without interfering with each other. This is achieved by directing gain towards subscriber stations of interest while simultaneously placing nulls on interfering transmitters. Recently, researchers and developers have developed keen interests in OFDM-SDMA system because of its ability to provide spectrally efficient wireless services, similar to the CDMA system, but at low complexity/costs. SDMA helps to achieve high spectral efficiency, by multiplexing multiple users on the same time-frequency resources. OFDM on the other hand provides cheap, efficient high data rate services through parallel data transmission on the OFDM subcarriers. On the other hand, there are still challenges facing the design of efficient multi-user detection for OFDM-SDMA that allow effective separation of the multiplexed SDMA user data on each subcarrier, at acceptable symbol error rate (SER). So far, existing efforts in developing multi-user detection techniques for OFDM-SDMA applications have focused mainly on the SER performance enhancements. In our recent works, however, we proposed a capacity-aware multiple-input multiple-output - maximum ratio combining (MIMO-MRC) scheme that exhibits better system capacity and SER performance for the OFDM-SDMA application than the existing MIMO-MRC system. Therefore in this research work, we will investigate the capacity-aware version of other detection schemes such as MMSE and MLSE/MLD schemes. Direct enhancement in system capacity will be incorporated in the detection criterion of these schemes, to facilitate deployments over broadband wireless networks. Hardware prototypes of selected schemes will then be developed to serve as a platform for their introduction to interested industrial partners.