Smart RoF systems for spectrally efficient WLANs

如今，无处不在的通信依赖于两种服务的可用性：1）到网络网关的无线连接，以及2）将网关连接到因特网的有线（或光纤）骨干。通过将无线链路的RF处理通过光纤基础设施移回集中点，我们可以实现先进信号处理技术的承诺，以实现巨大的带宽、服务质量和鲁棒性。视频电话、会议和多媒体服务是从这种基础设施中受益的一些更明显的应用，但也可以想象其他更未来的应用。可穿戴计算设备可以无线地访问本地可用的高分辨率显示器，基于互联网的协作将享受对所有本地信息、设备、设施等的无缝访问。无线信道固有地带宽有限，并且我们必须转向复杂的调制格式、多个和智能天线系统以及利用丰富的多径返回。所有这些都需要复杂的信号处理，更重要的是，需要侧边信息和跨物理传播区域的接入点协调。只有光纤才能提供将射频信号传输到中央处理中心所需的带宽，因此本项目将无线和光纤通道结合起来，提供一种端到端的高性价比技术解决方案。我们的研究将研究无线和光纤通道结合对WiFi信号传输的影响，并提出新的缓解措施来补偿通道缺陷。我们将提出充分利用接入点与多个天线的干扰抑制，范围增强和有效的多路复用的协调例程。我们的努力将使网络在单位面积支持的用户数量和总吞吐量方面具有更大的容量。

Ubiquitous communications today relies on the availability of two services: 1) a wireless connection to a network gateway, and 2) a wired (or fibered) backbone connecting the gateway to the Internet. By moving the RF processing of wireless links back through the fibered infrastructure to a centralized point, we can achieve the promise of advanced signal processing techniques to achieve tremendous bandwidth, quality of service and robustness. Video telephony, conferencing and multimedia services are some more obvious applications to benefit from such an infrastructure, but other more futuristic applications can also be imagined. A wearable computing device could access locally available high resolution displays wirelessly, Internet based collaborations would enjoy seamless access to all local information, equipment, facilities, etc.The wireless channel is inherently bandwidth limited and we must turn to sophisticated modulation formats, multiple and intelligent antenna systems, and exploitation of rich multipath returns. All this requires complex signal processing, and, more importantly, side information and coordination of access points across the physical propagation area. Only optical fiber provides the necessary bandwidth to transport the RF signals to a central processing center, hence this project makes the wireless and optical channels play together to provide an end-to-end cost-effective technological solution.Our research will examine the effect of the combined wireless and optical channel on the transmission of WiFi signals and propose new mitigation efforts to compensate for channel imperfections. We will propose routines that exploit fully the coordination of access points with multiple antennas for interference suppression, range enhancement and efficient multiplexing. Our efforts will yield networks with greater capacity in the number of users supported per unit area, and also in total throughput.