Boreal Aquatic Ecology

自适应空分多址(SDMA)被认为是即将到来的4G技术支持的一种重要的高级选项。这些先进的天线技术预计将对无线链路提供的容量和服务质量以及可用频谱的有效利用产生重大影响。这些系统可用于同时接入同一重叠覆盖区域中的不同用户站，而不会彼此干扰。这是通过将增益引导到感兴趣的用户站，同时在干扰发射机上放置零位来实现的。近年来，由于其能够提供类似于码分多址系统的频谱高效的无线业务，但其复杂度/成本较低，因此引起了研究人员和开发人员的浓厚兴趣。SDMA通过在相同的时频资源上多路复用多个用户来帮助实现高频谱效率。另一方面，通过在OFDM子载波上进行并行数据传输来提供廉价、高效的高数据速率服务。另一方面，仍然面临着设计用于ofdm-sdma的高效多用户检测的挑战，其允许以可接受的误码率(SER)在每个子载波上有效地分离复用的sdma用户数据。到目前为止，已有的开发用于ofdm-sdma应用的多用户检测技术的努力主要集中在误码率性能的增强上。然而，在我们最近的工作中，我们提出了一种容量感知的多输入多输出最大比合并(MIMO-MRC)方案，该方案比现有的MIMO-MRC系统具有更好的系统容量和误码率性能。因此，在这项研究工作中，我们将研究其他检测方案的容量感知版本，如MMSE和MLSE/MLD方案。系统容量的直接增强将被纳入这些方案的检测标准中，以促进在宽带无线网络上的部署。随后将开发选定计划的硬件原型，作为向感兴趣的行业合作伙伴介绍这些计划的平台。

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.