SP: COLLABORATIVE RESEARCH: MAMA (Multiple Antennas Multiple Appliances) Wideband Wireless Networks: A Pervasive Technology for the Home and Workplace

两种截然不同的无线通信形式，一种已经建立并显示出惊人的增长，另一种才刚刚出现，有可能极大地影响家庭和工作场所无线通信的性质。一个是以802.11x/802.15为代表的日益高速的信息链路，最初应用于宽带互联网接入，但也转向视频和音频娱乐分发；另一个是传感器网络，可以提供安全、医疗监控和各种其他重要服务。不幸的是，这些用法在很大程度上是不相容的。高速率应用通常具有足够的电源以用于传输和处理目的。服务中断可能会令人恼火，但一般来说，它们不会威胁到健康或安全。另一方面，传感器网络涉及的消息通常很短且不频繁，但可能具有很高的重要性(考虑入侵或火灾警报，或儿童监视器)。此外，这类传感器(和不太重要的环境传感器)通常需要独立于永久电源的放置，因此需要节能操作。通常，这种不同的要求会建议将这些应用分离到不同的频段，但未经许可的频段的出现表明，设计师将无法选择如此舒适的隔离。因此，重要的是要考虑这些应用如何在相同的频率空间内共存。特别是，人们可能会推测，在我们在家庭和企业中发现的私人空间内，这种共存的潜力将得到增强-在这个空间中，无线电传输可能由单个实体有利地控制，并且系统内干扰占主导地位。这一提议的前提是存在解决方案，这些解决方案可以允许各种不同的应用程序在这样一个有限但受控的空间内高效共存。特别是，研究人员认为，以多天线和多设备(MAMA)为特征的协调使用代表了一种新型的网络，并提供了有效地互操作这些不同系统的重要机会。为了适应这种混合的比特率和能量要求，研究人员提出了一种综合方法，包括链路层、MAC层和跨层技术。在链路层，研究提出：-灵活的带宽调制格式和空间复用和分集。使用由应用程序设置的设备传输速率，设备的信令带宽相对于由干扰避免考虑或由能量限制确定的功率级别被优化。我们将论证这将导致以低信噪比(Low-SNR)为特征的超宽带(UWB)调制。-在几种模式中利用多个发射和接收天线：(1)在多输入多输出(MIMO)模式中，利用信道来提高比特率；(2)在分集模式中，空间分集提高功率效率；(3)在波束形成模式中，发射机天线将能量从其他设备和网络引导出去。与UWB信令一致，我们的研究将集中在MIMO系统的低信噪比机制上，由于链路层技术不能满足MAMA网络的所有复杂需求，研究人员提出了一种跨层方法，该方法考虑了网络的分布式、非协作性，以实现更有效地利用网络功率和带宽资源。跨层方法由两部分组成：-博弈论方法：基于依赖于发射功率和吞吐量的效用函数，用户调整其发射器和接收器以最大化其各自的效用。-“薄”MAC层协议：对于给定的物理层发射器和接收器，增量冗余混合ARQ提供非协作的速率适应和频谱资源共享。所提出的空间-频率-跨层的无线网络设计方法与传统的网络设计截然不同，在给定的带宽和功率下，数据速率最大化，通常忽略网内和网间的干扰。UWB、MIMO和跨层技术在MAMA网络中的并存跨越了一个多维的信号空间，这将产生一系列丰富的研究问题和网络体系结构。广泛的影响：这里提出的工作(如果成功)将使新的高速无线应用与家庭和工作场所新兴的传感器网络共存成为可能。虽然讨论的重点是家庭和工作环境，但应该理解的是，这些应用程序更广泛--到医院、工厂和一些机器人场景。MAMA网络也为学术机构的教育目标提供了一个令人兴奋的平台，包括本科生和研究生的活动。参与这一提议的研究机构包括普林斯顿大学、新泽西理工学院和罗格斯大学，以及无线通信系、贝尔实验室和朗讯。这项工作将在新泽西州无线电信中心(NJCWT)的赞助下进行。NJCWT是一个由新泽西州科学技术委员会发起和资助的跨机构研究和教育组织。

Two rather different forms of wireless communications, one already established and showing dramatic growth and the other only on the horizon, have the potential to impact dramatically the nature of wireless communications in the home and workplace. One is the increasingly high-speed information link typified by 802.11x/802.15, first applied to broadband internet access but moving toward video and audio entertainment distribution as well, and the other is the sensor network, which can offer security, medical monitoring, and a variety of other important services. Unfortunately these usages are largely incompatible. High-rate applications will generally have adequate power sources for both transmission and processing purposes. Service interruptions have the potential to be annoying, but they are not, in general, threatening to health or safety. Sensor networks, on the other hand, involve messages which are generally short and infrequent, but which may have a high level of importance (consider intrusion or fire alarms, or childmonitors). Moreover, such sensors (and less critical environmental sensors) often require placement that is independent of permanent power sources, and thus require energy efficient operation.Normally, such disparate requirements would suggest the separation of these applications into different frequency bands, but the emergence of unlicensed bands suggests that designers will not have the option of such comfortable isolation. It is therefore important to consider how such applications may coexist within the same frequency space. In particular, one may speculate that the potential for such coexistence would be enhanced within the private space that we find in homes and businesses - a volume in which radio transmission may be beneficially controlled by a single entity, and in which intra-system interference dominates. It is the premise of this proposal that solutions exist that can allow a wide variety of disparate applications to coexist efficiently within such a constrained, but controlled space. In particular, the researchers believe that coordinated usage characterized by multiple antennas and multiple appliances (MAMA) represents a new type of network, and offers significant opportunities to interwork such disparate systems efficiently.To accommodate this mixed set of bit-rate and energy requirements, the researchers propose a comprehensive approach that encompasses link layer, MAC layer and cross-layer techniques. At the link layer, the research proposes:-Flexible bandwidth modulation formats and spatial multiplexing and diversity. With the device transmission rate set by the application, the signaling bandwidth of a device is optimized versus a power level determined either by interference avoidance considerations or by energy constraints. We will argue that this leads to ultra-wideband (UWB) modulation characterized by low-signal-to-noise-ratio (low-SNR).-Multiple transmit and receive antennas to be utilized in several modes: (1) in multi-input multi-output (MIMO) mode, the channel is harnessed to increase bit-rate; (2) in diversity mode, spatial diversity enhances power efficiency; (3) in beamforming mode, transmitter antennas direct energy away from other devices and networks. Consistent with UWB signaling, our research will focus on the low-SNR regime for MIMO systems.Since link layer techniques cannot address all the complex requirements of MAMA networks, the researchers propose a cross-layer approach that takes into account the distributed, non-cooperative nature of the networks to achieve a more efficient use of the network power and bandwidth resources. The cross-layer approach consists of two components:-Game theoretic methods: based on utility functions that depend on transmitted power and throughput, usersadapt their transmitters and receivers to maximize their individual utilities.-"Thin" MAC layer protocols: for given physical layer transmitters and receivers, incremental redundancy hybrid ARQ provides non-collaborative rate adaptation and spectrum resource sharing.The proposed space-frequency-cross-layer approach to designing wireless networks is distinctly different from conventional network design where data rate is maximized for a given bandwidth and power, generally ignoring intra- and inter-network interference. The juxtaposition of UWB, MIMO and cross-layer techniques in MAMA networks spans a multidimensional signal space that will create a rich set of research problems and network architectures.Broader Impact: The work proposed here (if successful) will make possible the coexistence of new high-speedwireless applications with emerging sensor networks at home and in the workplace. Although the discussion focuses on the home and work environments, it should be understood that the applications are more widespread - to hospitals, factories, and some robotic scenarios. MAMA networks also provide an exciting platform for the educational goals of the academic institutions, including activities for both undergraduates and graduate students.The research institutions involved in this proposal are Princeton University, the New Jersey Institute of Technology, and Rutgers University, and The Wireless Communications Dept., Bell Labs, Lucent. The work will be done under the auspices of the N.J. Center for Wireless Telecommunications (NJCWT). The NJCWT is an inter-institutional research and educational organization sponsored and funded by the N.J. Commission on Science and Technology.